WO2012030236A2 - A multistep method of producing fuels, fuel precursors and chemicals from microalgae or lipid containing biomass and metal bases - Google Patents

Abstract

Methods for producing a fuel or fuel precursor and other products from lipid-containing biomass comprising heating an aqueous slurry comprising lipids containing biomass and water in a pressure vessel in the presence of a metal base to produce a solid phase comprising one or more precipitated metal soaps and an aqueous phase, seperating the solid phase from the aqueous phase, and heating the solid phase to the decomposition temperature of the one or more metal soaps.

Description

A MULTISTEP METHOD OF PRODUCING FUELS, FUEL PRECURSORS AND CHEMICALS FROM MICROALGAE OR LIPID CONTAINING BIOMASS AND

METAL BASES FIELD OF THE INVENTION

[0001] The present invention relates to a method of processing hydrothermally lipid containing biomass such as algal biomass in the presence of certain metal bases such that following the hydrolysis of lipids, the lipid acids form insoluble soaps, while nitrogenous and oxygenated materials remain dissolved in the aqueous phase, thus making it easier to separate and purify the different classes of chemicals and also significantly preventing cross-reactions between different classes of materials, thus obtaining better yields of each class of useful chemicals, particularly nitrogen heterocyclic materials and liquid fuel or liquid fuel precursors that are essentially free of nitrogenous contaminants. BACKGROUND TO THE INVENTION

[0002] Currently, virtually all transport fuels and most of the carbon-based products of the chemical industry come from oil. Recendy, it has become apparent that such oil supplies are limited, and a replacement source of such fuels and chemicals will be required. While various proposals have been made for electric-powered transport, it seems highly likely that a high demand for liquid fuels will continue into the immediate future. Further, there is a need to replace many of the materials dependent on oil, and in particular organic chemicals for making polymers. Accordingly, there is considerable need to find different sources for these materials.

[0003] While nitrogen introduces interesting properties to polymers, and a number of natural polymers such as proteins, enzymes and nucleic acids make use of nitrogen, the cost and difficulty of introducing such nitrogen has led to relatively little use being made of nitrogen containing synthetic polymers.

[0004] It has also become desirable to reduce the emissions of what are commonly called greenhouse gases into the atmosphere, many of which arise from burning fossil fuels. Since all the greenhouse gases emitted by burning fuels derived from biomass represent materials originally derived from the atmosphere and not of carbon that was removed from the biosphere through fossilization, there is a benefit in obtaining such fuels from biomass. [0005] Many sources of biomass, and in particular, microalgae, contain significant levels of nitrogen, and since emissions following the combustion of such materials may contain materials such as nitrogen oxides, which are also greenhouse gases as well as sources of general pollution such as smog, it is desirable to be able to remove such nitrogen containing material from fuels. [0006] On the other hand, many nitrogen-containing heterocyclic compounds are valuable for the chemical industry, being used as solvents and in the food and pharmaceutical industries, hence there is no reason to avoid nitrogen containing biomass, as long as the nitrogenous material can be separated from other material.

[0007] One means of obtaining fuel is through the processing of lipid-containing biomass. A high proportion of the lipid molecule consists of linear hydrocarbon suitable for fuel. Consequendy, considerable interest has been shown in using such molecules for diesel fuel, and indeed the first diesel motor ran on peanut oil. For various reasons, lipids not used as food are now frequently transesterified to make the methyl esters of the lipid acids, and this product is termed biodiesel.

[0008] However, most biomass is of cellulosic origin, and only has significant lipid

concentrations in seeds, nuts, etc. Much of this oil is. used for food purposes, and to avoid unpleasant residues, the oil is obtained by pressing, but when oil is obtained by this method, there are significant amounts of lipids remaining in the residues. An example includes the vast amounts of wastes from olive oil production, which is effectively unprocessable at present. Such wastes have considerable potential for fuel production and while they might provide only a minor contribution to the oil problem, nevertheless finding a use for the olive oil wastes could be regionally significant.

[0009] Microalgae are amongst the fastest growing plants on the planet, and have the rather unusual property (for plants) of storing energy in the form of lipids, and it is possible to raise the lipid levels of some micro-algae to in excess of 50 % by weight.

[0010] Notwithstanding that, utilization of microalgae for fuels has so far been limited. The usual approach has been to produce biodiesel by extracting the lipids and transesterifying them by methods well-established in the art, or by taking these lipids and hydrocracking them, or using other refining techniques well-established in the art to produce hydrocarbons suitable for use as liquid fuels.

[0011] Generally speaking, microalgae with high lipid content have only been produced through carefully controlled growing conditions, such as with bioreactors, but this seriously raises the unit cost of the microalgae. [0012] Wild algae, which are readily available in places such as sewage treatment facilities that are already built, are inherently cheaper but under the prevailing conditions of such operations, the algae devote energy towards reproduction rather than lipid accumulation, hence the raw material has much less hydrocarbon potential. [0013] In each case, there are problems in obtaining pure lipids. Extraction methods such as pressing are not usually available because microalgae are too soft. Solvent extractions do not work at all well if the algae is wet, which implies expensive drying is required and the cost of the final product will be highly dependent on obtaining high yields of lipids. For algae grown in sewage treatment facilities, the yield of lipids is relatively low. [0014] To date, successful development of a commercial process based on an economically viable method of producing biodiesel or other biofuels or fuel precursors from algae does not appear to have been achieved and there remains a need to provide such a process or to at least go some way towards providing such a process. It would therefore be advantageous to be able to produce biofuels from low value, high yielding biomass such as micro-algae growing in waste water, or the wastes from the production of lipids from other biomass sources, but for these to be a promising low value biomass source for such fuel and chemical production, an improved process is required, preferably one that will use components in addition to lipids.

[0015] Also, there is considerable interest in obtaining the precursors to polymers, etc., from biological sources, where proteins and cellulose could be used as a source of potential precursors. Accordingly, biomass containing levels of lipids too low to be of current interest, such as microalgae from sewage treatment plants and waste pressings from olive oil manufacture, might be of considerably more interest if both lipids and protein or cellulose could be processed to make useful materials.

[0016] One possible alternative process is hydrothermal liquefaction. The concept that biomass could be heated with water to near supercritical conditions to produce liquids is reasonably well- established in the art. Thus during the 1970s energy crises, the US Bureau of Mines produced a number of reports on the heating of lignocellulose in water, and found that oxygenated liquids that were considered to be suitable for refining to liquid fuels could be produced, and that the liquefaction process proceeded better in the presence of sodium carbonate, which was added to provide mild alkaline conditions. The hydrothermal processing of protein matter has been studied sufficiently well that a commercial plant has been built at Carthage, Missouri, although it is unclear to the general public whether the products it produced were optimal, or, for that matter, what they were. [0017] We have shown previously (WO/2010/030197) that besides being able to make some hydrocarbons, the protein fractions in microalgae also make useful chemicals that contain nitrogen when the microalgae are processed under hydro thermal conditions. However, the yields of such valuable low-boiling materials are variable, and mass balance considerations and product analysis indicates that the protein-derived chemicals then react with some of the unsaturated lipid-derived products to make higher molecular weight materials that have no immediate value, while attempts to prevent this by moderating the catalysts seem to produce unreacted lipid acids. The problem seems to be that desirable materials form quickly, but then proceed to further react to form materials that are at least to some extent less desirable, or alternatively reactions do not proceed far enough. [0018] The value of lipids for making fuel is that the lipid acids consist of long chain hydrocarbons bound to the carboxylic acid, and these hydrocarbon chains would make excellent diesel fuel. Accordingly, it would be desirable to decarboxylate these acids to give alkane chains, however while this appears to be possible, in practice it appears that the decarboxylated fragments condense further with nitrogenous materials that are too high boiling, and are likely to give polluting effluents, or be thought to give polluting effluents.

[0019] Such materials could possibly be hydrocracked before use for fuels. In practice, some of the nitrogenous materials such as indoles are only converted to hydrocarbons with extreme difficulty and with a considerable loss of yield of the non-nitrogenous hydrocarbon-bearing fraction, which greatly increases the unit cost of the resultant fuel. Accordingly, there would be a clear advantage if the potential hydrocarbons could be made separately from the nitrogen-bearing chemicals.

[0020] At the same time, a number of interesting nitrogen-containing heterocycles were prepared from microalgae by hydrothermal liquefaction, but it appears from the analysis of the products under certain conditions that these useful heterocyclic materials, while thermally stable, appear to react chemically with other useful materials produced from the biomass to produce materials with no obvious use. Thus besides reducing the yield of fuel, the yield of useful heterocyclic materials also declines and the mass of material with no immediate value, but which will incur costs in disposing of it, increases. Accordingly, it would be desirable to also prepare as many as possible of the various classes of materials separately.

[0021] To summarize, minimal progress has been made on producing bio fuels and heterocyclic chemicals from micro-algae, economically or energetically for at least some of the following reasons:

1. Micro-algae grow in low biomass concentrations, which are very difficult to convert efficiently to high concentrates of microalgae. 2. A significant problem with producing microalgae with a high lipid content is that special conditions are required, and these may vary between species. Accordingly, selected species have to be cultivated under carefully selected conditions, which imposes considerable cost, not the least because wild algae must be excluded, and wild algae are extremely adept at coloni2ing aqueous environments.

3. The extraction of lipids from wet microalgae is a difficult process from which to get good yields of lipids. The losses occur through the microalgae absorbing solvent, and from the tendency of the system to form emulsions/ sludge dispersions, from which it is difficult to recover all materials.

4. The drying of microalgae concentrate is expensive.

5. Hydro thermal liquefaction avoids the need to dry the microalgae and gives rise to a variety of useful products, but the mixtures are complicated and the products tend to react further amongst themselves, so that the end products are frequendy very viscous oils with high levels of nitrogen chemically bound in the form of aromatic rings {e.g. condensed pyrroles).

6. Such oils can be upgraded by hydrocracking only with difficulty, and with a sacrifice of yield.

7. Once further condensed, the initial heterocyclic materials are not recoverable, and the

condensed products do not have further uses, at least as yet.

[0022] Many of the above problems could be addressed if, when processing lipid rich biomass, the lipid fraction could be kept in a separate phase from the nitrogenous heterocycles, and various classes of heterocycles could be kept separately, as this would minimize the opportunity for the hydrocarbons to react with the nitrogenous material to make the materials that are difficult to use or further process. If this could be achieved, while the number of processing steps must increase, by stopping certain subsequent condensation reactions it may be possible to manufacture nitrogen-free fuels, while at the same time isolate useful chemicals from the aqueous phase. We have found that this is the case, and the alternative approach gives a useful addition to the range of processing options.

[0023] We now demonstrate that microalgae can be used to make a variety of useful materials by reacting them hydrothermally with a set of metal bases as defined below under a specific range of processing conditions, and some of the particular chemical materials that are made can be directly used both for chemicals and transport fuel. The organic residue is expected to be suitable for further refining and the inorganic residue is suitable either for recycling, or for other uses, for example, soil conditioning and fertilizer. In particular, our invention takes specific advantage of lipid content, and accordingly will be particularly relevant to material of biological origin that is rich in lipids, or contains lipids or fatty acid components that would otherwise be unusable. Accordingly, we believe that our invention will significantly enhance the variety of sustainable feedstocks of biological origin that will be required to replace those currently obtained from the non-renewable oil industry, or at least provide the public with a useful choice.

SUMMARY OF THE INVENTION

[0024] In a first aspect, the present invention relates to a method for producing a fuel or fuel precursor from lipid-containing biomass comprising:

(i) heating an aqueous slurry comprising lipid containing biomass and water in a pressure vessel at a temperature of about 200°C to about 350°C in the presence of a metal base to produce a solid phase comprising one or more precipitated metal soaps and an aqueous phase,

(ii) separating the solid phase from the aqueous phase, and

(iii) heating the solid phase to the decomposition temperature of the one or more metal soaps.

[0025] In a second aspect, the present invention relates to a method for producing a liquid fuel or liquid fuel precursor and useful chemicals from an algal biomass, the method comprising:

(i) heating the algal biomass in the presence of water and a metal base in a pressure vessel to temperatures greater than that required to hydrolyse the lipids but below that where degradation of the metal soap begins, such temperatures varying depending on the base as shown below, to produce a fluid and a solid residue,

(ii) separating the solid residue from the fluid,

(iii) further heating the fluid to temperatures of about 325 to about 500°C to convert the

dissolved material to useful chemicals, then substantially separating the organic fraction in the fluid from the water for the purpose of producing useful organic chemicals, and

(iv) recovering fuel or fuel precursors, essentially free of nitrogenous material, from the solid residue.

[0026] In a third aspect, the present invention relates to a method for producing a liquid fuel or liquid fuel precursor and useful chemicals from an algal biomass, the method comprising: (i) heating the algal biomass in the presence of water and a metal base from the group 2 metals in a pressure vessel to temperatures of about 250— 300°C, preferably to approximately 275°C, to produce a fluid and a solid residue,

(ii) separating the solid residue from the fluid,

(iii) separating a stream of nitrogen heterocycles that are rich in pyrazines from the fluid,

(iv) further heating the fluid to temperatures of about 325 and 500°C to convert the dissolved material to further useful chemicals, then substantially separating the organic fraction in the fluid from the water for the purpose of producing useful organic chemicals, and

(v) recovering fuel or fuel precursors, essentially free of nitrogenous material, from the solid residue.

[0027] In a fourth aspect, the present invention relates to a method for the separation and isolation of certain chemicals produced with the methods of the first, second and third aspects that can be then sold as sustainable replacements for materials currendy manufactured from the oil industry.

[0028] In a fifth aspect, the present invention relates to a method involving further pyrolysis, including hydrothermal pyrolysis, for the preparation of fuel components produced with the methods of the first, second and third aspects that can be separated into components by distillation that can then be sold directly to enhance the octane rating of petrol and as a high cetane rated diesel fuel.

[0029] In a sixth aspect, the present invention relates to a method for the use of the residue from the first, second, third, fourth and fifth aspects being useful as a feedstock for further refining to liquid fuels.

[0030] In a seventh aspect, the present invention relates to a method for recovering the inorganic catalyst, and either reusing it or making it available for alternative uses.

[0031] In an embodiment of this aspect, phosphate may be recovered in a form useful as a fertilizer, thus recovering phosphate from an effluent stream that would otherwise act as a pollutant.

[0032] In an eighth aspect, the present invention relates to use of ethyl benzene or styrene obtained from the mixture produced according to a method of the invention for manufacturing polystyrene of biological origin. [0033] In a ninth aspect, the present invention relates to use of dialkylated or polyalkylated pyrazines obtained from the mixture produced according to a method of the invention for manufacturing by oxidation pyrazine dicarboxylic acids or pyrazine poly carboxylic acids or anhydrides for the precursors of condensation polymers of biological origin. [0034] The following embodiments may relate to any of the above aspects.

[0035] In various embodiments the aqueous slurry is heated at about 200, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340 or 350°C and useful ranges may be selected between any of these values.

[0036] In various embodiments the solid phase is heated at about 300°C or more, about 300 to about 900°C, about 300 to about 600°C, about 400 to about 900°C, or about 400 to about 600°C.

[0037] In one embodiment the method further comprises separating one or more organic chemical products from the aqueous phase.

[0038] In another embodiment the method further comprises obtaining further chemical materials by separately heating the aqueous phase to temperatures of about 350°C and 500°C, optionally in the presence of a catalyst.

Feed materials

[0039] The preferred feed material for the purposes of this invention is an aqueous dispersion or slurry of a lipid containing organic material, such as a biomass, and a metal base. In various embodiments the lipid containing biomass comprises about 2, 10, 15, 20, 25, 30, 35, 40, 45 or 50% to about 90% dry weight equivalent of the slurry.

[0040] A preferred lipid containing biomass for the purposes of this invention is algae or microalgae but any of the following biomasses are contemplated, alone or in any combination.

[0041] A further preferred lipid containing biomass for the purposes of this invention is lipid containing plant material, such as but not limited to, plant oils, oil-containing seeds, non-pressed jatropha, palm-oil, olives, etc, and wastes resulting from the processing of such oil-containing material, such as olive oil pressing waste. Waste oils may also comprise the biomass, or be included with other biomass, such as waste cooking oils.

[0042] A further preferred lipid containing biomass for the purposes of this invention is any material rich in protein and lipids, including biomass of animal origin, such as fish and meat that may otherwise be unsuitable for food use for any reason, including any level of bacterial or fungal growth, and including meat, fish, and bird processing wastes.

[0043] A further preferred supplement for the purposes of this invention is any waste lipid source or source of fatty acids, such as, but not limited to, waste cooking oil, waste soap, waste tallow, or meat processing off-cuts that would otherwise be wasted.

Metal bases

[0044] The metal base is a material that reacts with acid to form a salt and materials that are only mildly acid or are neutral. Preferably an aqueous solution of such a salt will precipitate an insoluble stearate if the solution is mixed with a solution of sodium stearate. Useful metal bases are discussed in greater detail below. The amount of metal base used should preferably be sufficient to react with (or adsorb) all carboxylic acids formed, and hence will depend on the lipid content of the raw material. In practice, a small excess should be used, since the exact composition of the feedstock is unlikely to be known.

[0045] In one embodiment the metal base is an oxide or hydroxide. In another embodiment the metal base is a carbonate or a sulphide. In various embodiments the cation in the metal base is divalent, including but not restricted to magnesium, calcium, barium, strontium, zinc, cadmium, copper, nickel, cobalt, manganese, vanadyl, tin, lead and ferrous. In still other embodiments, the cation in the metal base is trivalent, including but not restricted to ferric, aluminium, chromic, scandium and rare earths. Temperature of reactions

[0046] The algal biomass may be heated to a temperature of about 200— 350°C and useful subranges may be selected within this range. The selected temperature should depend on the time employed, on the nature of the metal in the base, on the desired non-lipid products, and on the nature of possible side reactions. The upper temperature range must be below the temperature at which a pure sample of the corresponding metal stearate would commence decomposing in water, and preferably the upper temperature should be 50°C below this temperature. Some example decomposition temperatures for pure metal stearate (D. Rogers, 1 84, Thermochim Acta 77, 123) are (in degrees C) for various cations Ca 440, Mg 375, Zn 350, Pb 340, Sn and Fe, 300. We have shown that in water, the higher of these temperatures are unsuitable as water then appears to assist decomposition. The higher temperatures achieve the desired ends more quickly, but they also carry the risk of unnecessary further reaction, including decomposition reactions induced by solvents, while the alkalinity of the base may change the nature of the co-produced products. Most of the examples listed below have been selected on the basis of assisting the production of lipid-derived fuels, but our invention is also suitable for producing other materials that we have identified, and the optimum conditions for producing them may be different from those for producing fuels.

Heating time [0047] Preferably, the algal biomass may be held at the desired reaction temperature for a time period of less than about 180 minutes, more preferably for about 1 minute to about 60 minutes, even more preferably for about 5 minutes to about 40 minutes. The exact time chosen is dependent on the efficiency of the mixing and the shear in the system, and will vary dependent on the precise mechanical aspects of the equipment. Pressure

[0048] The pressure is that which is required to maintain appropriate phases of components in the pressure vessel and which may aid control of the reaction at preferred reaction temperature (s). It is of particular importance that sufficient water present to maintain the vapour pressure of water together with a good volume of liquid phase, otherwise unnecessary charring or pyrolysis may occur. pH

[0049] Because of the presence of bases, the pH of the reactions will be controlled by these bases.

Separation

[0050] The solid may be separated from the liquid produced by the reaction either by centrifugation, filtration or settling, and once so separated, the solid may be washed with solvent that may be used in other separation steps to remove adhering product. Alternatively, as the solid must be dried, the vapours from such a drying process may be condensed and optionally combined with other liquid phases.

[0051] In one embodiment, any substantially aqueous phase may be extracted with a solvent that is immiscible in water, then the solvent may be separated from the extract by distillation and used for further extraction.

[0052] Suitable extraction solvents that are immiscible in water include, but are not restricted to, methylene chloride, petroleum spirit, aromatic solvents such as toluene and xylene, ethyl acetate, ethers, etc. [0053] In a further embodiment, the solvent used to extract the aqueous phase may include solvent used to wash the solid, or used for any other washing process.

[0054] In a further embodiment, the pH of the substantially aqueous phase may be adjusted prior to extraction, such that the aqueous phase can be made alkaline to enhance the extraction of nitrogenous bases by an organic solvent, while the aqueous phase may subsequently be made acidic to enhance the extraction of water soluble organic acids. The extractions may also be carried out in the alternative order, i.e. the solution may be made acidic first. Extraction may be carried out by an organic solvent, or other solvent not soluble in water, or by an ion exchange material or any other selective adsorption process in which an acid or base form is substantially adsorbed in one form or desorbed in the other form, the isolation of selective materials being made by adsorbing them in either an acid or base form, and recovering the materials by desorbing them in the other, or by subsequent volatilisation.

[0055] In a further embodiment, the water-soluble materials may be adsorbed on charcoal, zeolite, silicalite, pumice, or any other porous material that can adsorb dissolved organic materials from water, with the adsorbed material subsequently recovered by distillation or solvent extraction.

[0056] In a further embodiment, the substantially organic phase of the liquid that is immiscible in water may be extracted with water or water that has been acidified to a desired pH to extract desired nitrogenous heterocycles from the organic phase, or made basic to extract carboxylic acids.

[0057] In a further embodiment, the reaction liquors may be flared off, taking the organic volatiles with them, but leaving the acids as salts, e.g. acetic acid produced in the presence of a calcium base will remain as calcium acetate, which, when the solids are pyrolysed, will make acetone.

Pyrolysis

[0058] The purpose of the pyrolysis is to convert metal soaps or metal carboxylate salts to the carbonate and either hydrocarbons or ketones. This may be carried out with or without a sweeping gas, which ideally would be an inert gas such as nitrogen, or under vacuum. If the objective is to use the pyrolysis for low molecular weight acids from the deamination of amino acids, then vacuum is generally unsuitable. Metal carboxylate salts are made by reacting the carboxylic acids with the metal bases defined below.

[0059] The pyrolysis of the solid soap is carried out at a temperature above the decomposition point, which, as noted above, varies between cations. We have favoured temperatures of about 400- 600°C, however our claims are for any temperature higher than the decomposition temperatures noted above. As the resultant solid is often a carbonate, and if it is desirable to reuse the material as a catalyst, it may be desirable to heat it to such a temperature that the partial pressure of carbon dioxide is significant. For calcium carbonate, this partial pressure is about 1 atmosphere at 900°C, hence the pyrolysis could proceed from 400— 900°C. Accordingly, in various embodiments the solid phase is heated at about 300°C or more, about 300 to about 900°C, about 300 to about 600°C, about 400 to about 900°C, or about 400 to about 600°C.

Optional processing steps

[0060] In various embodiments, the pressure vessel may be a batch reactor, a continuous or semicontinuous reactor, it may be stirred, fluid bed or fixed bed and may be horizontal or vertical. The metal bases may be admixed with the biomass source, precipitated onto them, or fed separately into the reactor.

[0061] Similarly, in various embodiments, the pyrolysis vessel may be a batch reactor, a continuous or semicontinuous reactor, it may be stirred, fluid bed or fixed bed and may be horizontal or vertical, and the heating may be by any means provided appropriate temperature control is maintained. At the end of pyrolysis, air may be passed through the resultant solid to burn off carbon, in order to recover the oxide to recycle it.

[0062] The pyrolysis vessel may also be a high-pressure vessel and the pyrolysis may be carried out under pressure, including under hydrothermal pressure.

[0063] If the aim is to reuse the metal base, then the final stage of the pyrolysis should be carried out at sufficient temperature in the presence of air to burn off any carbon.

DEFINITIONS

[0064] The term "algal biomass" as used in this specification means any composition comprising algae. The algal biomass may be partially de-watered, i.e. some of the water has been removed during the process used to harvest the algae, for example during aggregation,

centrifugation, micro-screening, filtration, drying or other unit operation The algal biomass may also comprise dried algae, to which water is added. It may also comprise additional biomass derived from other sources and may therefore implicidy comprise, without express statement of, "other contributing biomass" which may be biomass derived from other sources, such as for example biomass from land-based plant material. [0065] The term "lipid biomass" as used in this specification means any composition equivalent to that of biological origin that contains lipids, lipid acids, or corresponding molecules. Such biomass may have only residual lipids, such as the waste following olive oil production, or it may even be a waste product, such as used cooking oil, or a soap. The critical feature is that the material contains discernible amounts of molecules with the feature R-C0₂X, where X is any group or element.

[0066] The term "metal base" as used in this specification means molecules of the form M_n-X_m, where n and m are numbers to ensure that the rules of valence are followed, and where

(i) X is a group such that if M-X is reacted with an acid such that the pH < 3, we obtain the M salt and water, or some further species. Examples of suitable bases include, but are not limited to, oxides, hydroxides and carbonates, which in the latter case carbon dioxide is also produced. A further example of a material producing a different product is a sulphide, where hydrogen sulphide may be produced.

(ii) M is a metal such that it will form a salt with a mineral acid acting on the oxide and if such a pure salt is dissolved in water it will form a precipitate upon the addition of a solution of sodium stearate. Generally, a precipitate of the metal stearate results, but our claims are not dependent on the nature of the precipitate, and examples of suitable metals include, but are not limited to, group II elements such as magnesium, calcium, strontium barium, divalent elements such as lead, tin, copper, manganese, zinc, trivalent elements such as iron, aluminium, chromium, etc.

[0067] The term "liquid fuel" as used in this specification means a liquid that without further refining can be used direcdy, or in a blend, to provide energy.

[0068] The term "liquid fuel precursor" as used in this specification means a liquid that with further refining employing methods known to those practised in the art will provide a liquid fuel.

[0069] The term "oil" as used in this specification refers to any organic liquid recovered from a reaction, and the term does not imply anything about its composition.

[0070] The term "aqueous phase" as used in this specification refers to any phase that is substantially consisting of water, although it may have quite significant levels of organic material in it. [0071] The term "organic phase" as used in this specification refers to any phase that is substantially consisting of carbon-based materials and is separable from an aqueous phase, irrespective of other aspects of composition.

[0072] The term "soap" as used in this specification means the chemical product resulting from combining a lipid acid with a metal base, irrespective of whether it is soluble in water or has any surfactant properties.

[0073] The term "comprising" as used in this specification means "consisting at least in part of; that is to say when interpreting statements in this specification and claims which include "comprising", the features prefaced by this term in each statement all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in similar manner.

[0074] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

[0075] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. [0076] This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. [0077] - Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. DETAILED DESCRIPTION OF THE INVENTION

[0078] We commence by describing conceptually what we believe happens, although our invention does not depend on this interpretation. When biomass is heated in water, we consider that various chemical reactions occur sequentially as the temperature rises. One of the lower temperature reactions, particularly in the presence of metal bases, is the hydrolysis of lipids, and the resultant lipid acids form soaps with the bases if these are present. If the soap is insoluble in water, it forms a precipitate, and by taking it into a different phase, cross-reactions are prevented. Meanwhile, protein, nucleic acid, and starch remain in aqueous solution, either in their original form or as partially hydrolysed, while if any of these components rearrange thermally, the products will remain in solution.

[0079] This permits a three-way split of material. If this precipitate is removed from solution and pyrolysed, then only the lipid pyrolysis products are collected, and these hydrocarbons are substantially free of nitrogenous material. If the cooled aqueous solution is extracted, or if it is steam distilled or flared while cooling, a limited number of monomeric rearranged products containing nitrogen or oxygen may be obtained, essentially free of the remaining products that may be produced by hydro thermolysis of the protein and nucleic acids in the biomass. These final products can be obtained by further reacting the solution to supercritical, or near critical temperatures, preferably in the presence of some other catalyst.

[0080] This gives a significant advantage for processing at certain restricted temperatures. For example, algae can be heated anywhere of about 200°C and 350°C in the presence of calcium hydroxide and the insoluble soaps can be recovered and subsequently pyrolysed, without any particular effect on yield of pyrolysate, however at the lower temperatures the yield of nitrogen heterocycles is trivial, while at 350°C, most of the products formed from protein appear to be made. However, if the reaction is carried out in the 250— 300°C range for 30 minutes, most of the pyrazines that will form are made, and can be extracted free of most of the other classes of materials. Lower temperatures may give similar products if carried out longer, and similarly the selectivity may be maintained at higher temperatures if shorter times are employed.

[0081] At temperatures approaching 350°C, cellulose and other polysaccharides break down thermolytically, and at this point, most biomass components have been reduced to monomeric compounds, which in turn begin to fragment and to recondense. The advantage of turning a lipid acid into a soap is that provided the soap is kept below the pyrolysis temperature, it is inert to further reactions and cross-products do not form. Similarly, by operating at about 275 °C, the - nitrogenous materials do not react with the polysaccharide decomposition products, and the various components can be formed free of cross-reactions between the classes of intermediates.

[0082] At high temperatures and pressures in the presence of water, reductive fragmentation of amino acids and nucleic acids act as a source of ammonia and deaminated acids, which may react to form amides. While amides might be expected to hydrolyse under high temperatures with a considerable excess of water, we have found that some amides, such as acetamide, are so formed.

[0083] Carboxylic acids derived from protein after heating to near critical temperatures will be in the aqueous phase, but following acidification they may be extracted into organic phases, or adsorbed on porous materials such as charcoal, and very frequently acetic, propionic, isobutanoic, butanoic, 2- and 3-methyl butanoic, and valeric acids were extracted in our experiments. Such acids can be converted back to calcium salts by reacting the organic solutions with slaked lime. Soluble salts can also be recovered for pyrolysis by flaring off or evaporating off the water. The pyrolysis of salts of such acids form hydrocarbons or ketones, thus the pyrolysis of calcium acetate was the traditional way of making acetone prior to the supply of cheap propene from oil cracking. [0084] The first basic step in this invention is therefore to heat the microalgae, or other lipid- containing material, in the presence of a selected base and form an insoluble metal soap. The insoluble metal soap is then recovered by filtration and either pyrolysed or reacted hydrothermally to produce hydrocarbons suitable for fuel that are substantially free of nitrogenous material. The filtrate contains essentially all the nitrogenous material from the proteins and nucleic acids, either as monomeric products, or as soluble polymeric material, depending on the temperatures reached in the initial basic step. If the lipid-containing biomass is essentially cellulosic, then in order to solubilize the cellulose temperatures of about 350°C or greater are required, in which case the metal in the base should be restricted to calcium, strontium or barium.

[0085] The invention, therefore, defines conditions where these objectives are best met. If the temperatures in which the process is carried out are too hot, the metal soaps decompose and the fragments react with other nitrogenous material, thus decreasing the yield of both hydrocarbons and of useful nitrogen compounds. If the temperatures are too low, the various polymers do not hydrolyse and degrade sufficiently and the total yield of useful materials is too low, although, if the lipid acids are recovered, the remaining organic material may be further hydrothermally treated. [0086] The upper temperature range depends on the metal ion, but because the upper part of the range for metals such as calcium that have the higher range gives mixed organic fractions, the more useful range is similar for a number of oxides. [0087] There is an optimum temperature range that varies according to what we are trying to achieve. Our examples show that lipid hydrolysis and soap formation occurs easily at 200°C, however without further processing the yields of useful nitrogenated compounds from proteins are too low, while the yield of oxygenated materials from polysaccharides is negligible because the rate of hydrolysis of many polymers at this temperature, in the absence of catalysts, is very slow. On the other hand, such low temperatures offer the option of removing the soaps and further reacting the aqueous fraction with a different catalyst, thus permitting varying products from the protein. Thus when ferric ions were added to such a reaction, a number of pyrroles were formed, while pyrazines were not. [0088] It is important that there is sufficient metal base present to capture all the lipid acids. In this context it should be noted that most of these bases will also react with phosphate, which is present in all biomass, but particularly so in microalgae, hence the choice of metal must be made bearing this in mind. Accordingly, calcium is a particularly useful metal, as lime is usually readily available, and calcium phosphates are readily usable as fertilizer, while additional calcium carbonate is also useful.

[0089] In this context, magnesium is also useful, as the resultant phosphate can be converted to a magnesium ammonium phosphate, a useful fertilizer as it contains nitrogen, phosphate and magnesium.

[0090] It is also important that there is sufficient water present to inhibit charring. In subcritical conditions the amount of water required is that required to exert the saturated vapour pressure for that volume, and properly dissolve soluble material. The actual amount of water required will depend on the equipment design and also on the heating rate. Carbohydrates are probably the most prone to charring, and the first step in their reaction, depolymerization, seems to require relatively high temperatures (approximately 350°C for cellulose). However, if the monosaccharides fragment, the resultant fragments recombine in ways to make products much less prone to charring.

[0091] Following heating in step (i) of the process of the invention, the product stream may be cooled before the pressure is released. The resultant mixture may contain a fluid phase and a solid phase, the latter of which should be removed by filtering, centrifuging or settling. On the other hand, such methods of separating the solid phase from the liquid phase may also be carried out at higher temperatures and pressures, and our method merely requires this to be done, and our claims are independent of exactly how it is done. The solid may be washed with solvent to remove and recover materials from the fluid phase. [0092] At this point the liquid stream will contain substantially the nitrogenous and oxygenated organic materials, either dissolved in the water or, if cooled, as a separate phase. This liquid stream may optionally be extracted to obtain such materials, it may be steam distilled or alternatively it may be further treated hydro thermally to complete desired reactions. Our invention relates in part to the production of these separate streams, and while we illustrate by example methods of how to recover desired materials from the separate streams, our invention of how to produce these streams remains irrespective of how they are subsequently worked.

[0093] Steam distillation is a particularly attractive method if the solutions are only partially cooled. Thus steam distillation at atmospheric pressure or at pressures slightly higher leads to any aromatic hydrocarbons and the pyrazines to be distilled with the water, while lactams and higher boiling materials remain in the kettle.

[0094] We have found that the products of these reactions fall into several classes: nitrogen heterocycles such as pyrimidines, pyrroles and pyrazines, materials with oxygen and nitrogen such as lactams, oxygenated cyclic materials such Cyclopentenones, lactones and furaldehydes, phenols, carboxylic salts and aromatic hydrocarbons such as toluene. Finally there are numerous chemicals that are currently unidentified. These unidentified materials are generally of higher molecular weight, or they are present in only small amounts, although in some cases they are unidentified because a given eluant from the gas chromatograph comprised more than one chemical species.

[0095] If there is inadequate metal base, or inadequate mixing, or if the reaction proceeds too long or becomes too hot, there may also be linear hydrocarbons, such as pentadecene, resulting from the hydrothermal pyrolysis of soaps or the corresponding fatty acids.

[0096] Since all plant materials contain magnesium, complete separation of alkane/ alkenes from nitrogenous species is best achieved with temperatures below the pyrolysis of magnesium soaps, i.e. significantly below supercritical temperatures. [0097] As a consequence, there are several ways of proceeding. The filtrate may have certain materials such as pyrazines either in a separate layer or in aqueous solution, and if lactams are present in aqueous solution, they may permit aromatic materials such as toluene to partially enter the aqueous phase.

[0098] In one embodiment the residue of the filtration is washed with solvent that is insoluble in wafer, low boiling, and preferably moderately polar. One such suitable solvent is methylene chloride, however there are other solvents including but not limited to petroleum spirit, aromatic hydrocarbons such as toluene, diethyl ether and organic esters such as ethyl or amyl acetate. [0099] In a further embodiment, the solvent used for washing the residue, or for diluting the organic phase, or for extracting the aqueous phase, is toluene, xylene, or ethyl benzene previously made by the process, and partially recycled as an extracting fluid,

[0100] In a further embodiment, the pH of the aqueous phase is raised to approximately 12, so that amine salts are converted to amines, which are extractible into organic solvents. The various nitrogenous or oxygenated materials can then be recovered by distillation, or by other methods.

[0101] In a further embodiment, the initial aqueous phase can be made acid to pH <3, preferably <1, and well mixed so that the pyrazines and lactams are extracted into the aqueous phase, and carboxylic acids from the aqueous phase are extracted into the organic phase, and after separation, each phase undergoes further extraction and the extracts combined. If this is done, the carboxylic acids from amino acid de-amination are now in the organic phase, and can be recovered as calcium salts by treating the organic phase preferably with the metal bases, or more preferably with burnt lime or slaked lime.

[0102] The lactams and pyrazines may be recovered from an aqueous phase by methods well known to those practised in the art, such as re-extraction after neutralization, adsorption from the water onto a suitable substrate such as aluminium oxide or charcoal followed by distillation from the solid, ion exchange adsorption of the protonated species, etc.

[0103] A further isolation technique is steam distillation, which includes the option of flaring off water from hot pressurized solutions. We have found that at atmospheric pressure, the pyrazines steam distal whereas higher boiling materials such as lactams are less able to do so.

[0104] Adsorption is a useful means of concentrating certain products from dilute solution. Thus when acidified reaction solution was treated with activated carbon and the activated carbon was recovered by filtration, carboxylic acids were recovered as a more concentrated solution. When such solutions were treated with lime, the calcium salts were recovered and these could be pyrolysed,

[0105] The pyrolysis of the insoluble soaps and metal carboxylates leads to the production of volatile hydrocarbons and ketones, both of which may be used immediately as a diesel fuel without further refining. Also recovered from the pyrolyses are aromatic hydrocarbons, which are almost certainly not directly produced from corresponding soaps. While our claims are independent of this supposition, we believe the highly unsaturated lipid acids known to be present in microalgae fragment during pyrolysis and these fragments are the source of this aromatic material. The pyrolysis equipment requires only a heating chamber and a vapour condenser, although it is preferable that this be carried out in the absence of excess oxygen.

[0106] Similar products can also be prepared by reacting hydrothermally the metal soaps above the thermal decomposition point of that soap.

[0107] When the solids resulting from the addition of calcium bases to the organic fluid used to extract acids from the aqueous phase are pyrolysed, ketones usually result. Thus acetone results from acetic acid, diethyl ketone from propionic acid, dipropyl ketone from butyric acid (together with ethylene and propane) etc. Since the extract contains mixed acids, with a predominance of acetic acid, there will also be mixed ketones, with methyl ketones predominating. Such ketones are useful as industrial solvents, or they can be used as petrol additives.

OUTPUTS

The outputs of this invention include:

(i) Aromatic hydrocarbons, usually containing 7 or 8 carbon atoms, although condensed aromatic hydrocarbons are also produced in minor amounts. Specifically found are toluene, ethyl benzene and small amounts of xylenes, and occasionally significant amounts of naphthalene are produced. These hydrocarbons can be recovered by distillation from the organic phase, and apart from naphthalene are suitable for inclusion as high octane petrol, or as octane enhancers for other sources of petrol. They may be recycled as an extracting fluid, in which case, once a steady state is achieved, the production of these hydrocarbons is the same as if some other solvent was used. Ethyl benzene is also a precursor to styrene, hence a precursor to polystyrene. Styrene is also often a minor component of these reactions.

(ii) The ketones from the pyrolysis of low molecular weight acids can be fractionated by distillation, and acetone and methyl ethyl ketone are solvents of commerce. The other ketones may also be used as solvents, chemicals, or as petrol additives (after allowing for solvent attack on hosing, etc.).

(iii) Cyclopentanones, cyclopentenones and other ketones obtained by thermolysis of carbohydrates have uses similar to (ii). All such ketones may also be subjected to any of condensation, cracking, or hydrotreating to convert them to different fuels. They can also be used as solvents and intermediates for the synthesis of pharmaceuticals, insecticides and other biologically active chemicals, rubber chemicals, flavor and fragrance chemicals. (iv) Pyrimidines and pyrroles. These have general use in the chemical industry. Thus ben2pyrrole (indole) is used in the perfume industry and for pharmaceuticals.

(v) Pyrazines, substituted by varying numbers of methyl and ethyl groups. These are used currently as flavour enhancers, while the dimethyl pyrazine can be oxidized to the dicarboxylic acid, suitable as a component of specialist polyesters and polyamides. Of particular interest is that the nitrogen atoms permit special properties, particularly relating to interactions with water, thus very strong polymers have been made that have been claimed to be suitable for making films for reverse osmosis in desalination plants (Ger 1,941,022; 1970).

(vi) 2-pyrrolidinone and 2-piperidinone. These can be used to make nylon-4 and nylon-5

respectively, and hence would be useful for making fibres, etc from renewable sources.

(vii) N-alkylated lactams. These are of particular demand as high boiling polar solvents, although in principle they could also be used to make polyamides with reduced crystallinity.

(viii) Linear alkanes, alkenes, and higher-molecular weight ketones. These are made from the

pyrolysis of the soaps (although some may be made in the initial reactor) and can be used directly as diesel additives, or solely as a high cetane-rated diesel fuel.

DISCUSSION OF EXAMPLES

[0108] The initial step is to hydrolyse the lipids and collect the resultant fatty acids as an insoluble soap, which can then be separated from the liquids and then pyrolysed to make material suitable for use as fuels. Three conditions much be met for this to occur: the residue must be collected free of liquid, the soap must pyrolyse to give the desired components, and finally, the microalgae should not leave significant amounts of unreacted residue.

[0109] As was shown by the pyrolysis of a sample of calcium stearate, pyrolysis of such soaps gave long chain alkanes, alkenes, and alkanones consistent with this interpretation, which are highly suitable for direct inclusion in diesel fuels. In most of the examples below, the pyrolysate comprised alkanes, alkenes, aromatic hydrocarbons, or ketones that were essentially free of nitrogenous material, which shows that our goals were able to be met.

[0110] The occasional reaction contained a small amount of nitrogenous material such as indoles, and this is almost certainly due to adhesion of indole to the precipitate. In this context, indoles are tolerably soluble in hot water, but essentially insoluble in cold water, so the filtration should be carried out while the solution is hot, or at least warm. This is much easier to do on an industrial scale than in a laboratory, particularly when the effect was unexpected initially. The occasional reaction also resulted in the collection of lipid acids. This is a failure of the acids to react ^with the base, which implies that either insufficient base was present, or, as we believe, mixing was inadequate. These reactions were carried out in a shaken bomb, but heavier insoluble materials can sometimes cake and this would prevent access to some of the base. Accordingly, some form of stirring is required, or alternatively and preferably, the oxide/ hydroxide should have some solubility in water. For this reason, calcium hydroxide is a particularly desirable base.

[0111] Similarly, we have shown that in many examples that the aqueous phase contains recoverable heterocyclic compounds, substantially free of lipid acid derivatives. Accordingly, the clear separation has been achieved.

[0112] One pu2zling effect noted for calcium hydroxide was that the yields appear to become lower as the amounts of calcium oxide increase. This included the lipid fraction, thus at 250°C, the use of 1.86 g of calcium hydroxide resulted in a yield of 2.8 g pyrolysate, however if 9 g of calcium hydroxide was used, the yield or pyrolysate was approximately half of this. This may be a consequence of some additional reaction during pyrolysis, or, because the pyrolysis of large amounts of residue was carried out with smaller samples and the reported yields were corrected for comparison, poor mixing.

[0113] The overall yields varied significantly, but some of this variation is believed to be due to natural variation within the microalgae, and to experimental losses. On the other hand there was a clear variation with temperature of the extractives. At 200°C with calcium hydroxide a clear precipitate could be obtained that pyrolysed to give oil, but no volatile extractive could be obtained, presumably because the protein did not hydrolyse. On heating the filtrate to supercritical temperatures, however, a further 1.5 g of material was obtained. The reaction with 1.86 g of calcium hydroxide at 250°C gave a yield of pyrolysis oil of 2.77 g . [0114] When the reaction was carried out at 350°C with 9 g of lime and 18.6 g microalgae and the residues pyrolysed, a similar distribution of hydrocarbons but at a rather low yield was obtained. Rather puzzlingly, it was found that acids, including lipid acids, could be extracted from the aqueous phase, so the implication was that the lime at 350°C was being partially protected, possibly by coatings of calcium soaps. Rather surprisingly, the nitrogen heterocycles were also not formed in significant amounts.

[0115] Mixing dry microalgae with lime and pyrolysing the mixture also produced the expected hydrocarbon products, together with some pyrroles and some nitriles produced by the dehydration of amides from de-aminated aminoacids. Such long-chain nitriles can be converted to quaternary ammonium surfactants.

[0116] We have also shown that the fuels can be prepared from the residue by hydrothermal reactions. Thus when the microalgae was reacted with calcium hydroxide at 300°C, a solid residue and an aqueous solution was obtained, the aqueous solution containing a number of nitrogen heterocycles. However, when the solid residue was separated and further reacted hydro thermally at 400°C only hydrocarbons were formed in the oil.

[0117] The concept of precipitating the hydroxide worked well when precipitating aluminium hydroxide onto microalgae. One of the highest yields of oil was obtained, in part due to a relatively high yield of toluene, although this high yield may be in part due to a richer sample of starting material. While it may be that aluminium does not truly form a metal soap, our claim_' to using this is based on the products formed and not to strict adherence to the proposed mechanism.

[0118] Zinc oxide improved the filterability of the product and while very little reaction occurred at 200°C, reaction at 250°C gave yields of hydrocarbons (2.2 g) comparable to calcium hydroxide, and slightly better yields of oil following hydrothermal reaction (2.04 g). The hydrocarbon fraction was essentially free of nitrogenous material, and as a slight surprise, significant amounts of naphthalene were formed. It should be noted that with larger amounts of zinc oxide it was necessary to extract the residue to fully remove the oils which were adsorbed on the larger amount of residue. They could also be removed by slowly heating the residue prior to pyrolysis and collecting the distillate.

[0119] Copper oxide gave decreased yields of pyrolysate, nevertheless similar products were formed, which suggests that the reaction can- pproach reasonably closely to the pyrolysis temperature when that temperature is relatively low.

[0120] The use of magnesium oxide at 250°C with microalgae led to a similar set of products and again a large fraction of the organic material remained dissolved and not extractable. Clearly at 250°C, the separation into lipid derivatives occurs, however the full processing of the nitrogenous material does not proceed as completely. When the reaction was repeated, and the filtrate washed, the yield of eventual pyrolysate was significantly lower, and the product distribution altered. When processing natural materials there is always the possibility that the nature of the raw material was somewhat different, however some of the difference may arise through unprocessed algae being collected in the residue. [0121] However, with magnesium oxide the yield of oil at 330°C was very low, and at 300°C about midway of about 330°C and 250°C. Accordingly, there is a relatively narrow window of temperature that is useful, which is critical for this invention.

[0122] The use of ground chicken as a raw material showed the generality to other

proteinaceous sources. Again it was possible to isolate a hydrocarbon fraction essentially free of nitrogenous material, although the yield was not remarkable. This, of course, may have reflected the relative low fat content of the chicken, and it certainly reflects the high water content on animal body weight. Of some interest is the fact that the nitrogen heterocycles formed have higher levels of pyrroles than those formed from microalgae, a relative absence of pyrazines, and some slighdy different amines, presumably because the original protein is different.

EXAMPLES

Method

[0123] 300 mL of a slurry of microalgae (18.6 g estimated microalgae content, the microalgae having been collected, packaged and frozen) and catalyst in water was placed inside a stainless steel bomb, which was sealed, brought to temperature by placing it in the oven where it was left for the specified reaction time (30 minutes unless otherwise specified), then it was withdrawn and allowed to cool. The solids were then recovered either by filtration or by centrifugation. Through the course of this work, yields dropped over time, and it is likely that the samples initially used (and the last to be packaged) had settled somewhat, so the algal content may have varied. [0124] A sample of the solution was evaporated to determine the dissolved solids content.

These dissolved solids were subsequently ashed, and the difference between ash and total dissolved solids was taken as the non-volatile organic fraction. The bulk of the solution was then optionally subjected to extraction with lOOmL of CH₂C1₂, then the CH₂C1₂ was removed by evaporation to give the volatile oil components. (The yields were then corrected for the proportion of fluid previously removed.) The aqueous phase could then be further reacted at higher temperatures in the presence of catalyst, whereupon cooling this extraction with methylene chloride might be repeated. As a final optional extraction step, the solution was then acidified to pH 1 by addition of HNO, and extracted with 2 x 50 mL of CH₂C1₂ then made basic to pH 14 by the addition of NaOH and extracted with 2 x 50 mL of CH₂C1₂. [0125] Residues from the filtration, when pyrolysed, were placed in a round bottomed flask connected to a condenser and receiver, and heated progressively to approximately 600°C with a gas burner. The resultant oil was collected and analysed. [0126] Analysis of the extracts was carried out by gas chromatography/mass spectrometry on a Shimadzu GCMS QP2010 plus employing a RESTEK Rtx-5Sil MS 30M, 0.25mm ID film thickness 25um column. The injector temperature was 200°C, the split ratio was 10:1 and the interface temperature was 250°C. The oven temperature was programmed by being held at 50°C for 1 minute, then the temperature was increased at 5 °C/minute to 100°C, then 20°C/min to 300°C and held for 4 minutes. Run time 25 minutes in a linear velocity (30cm/ sec) mode. The mass spectra covered the 40-450 amu range, and product identification was carried out with assistance of the National Institute of Standards and Technology 2005 and 2005s compound database versions, and by examination of the spectra. Not all products could be identified, but many such unidentified compounds could be partially classified e.g. containing long chain hydrocarbon fragments. In some cases the inability to identify component arose because the GC resolution was incomplete, and the mass spectrum clearly arose from more than one component. In such cases, the material is not reported.

Example 1 Pyrolysis of calcium stearate. [0127] Calcium stearate was prepared by mixing a solution of calcium chloride with sodium stearate and decanting off the supernatent liquid. The pyrolysis of 2.8 g of this calcium stearate yielded 2.2 g of oil that comprised toluene (2.5%), nonene (4.5%), nonane (2.9%), decene (4.6%), decane (2.9%), undecene (4.2%), undecane (2.9%), dodecene (4%), dodecane (1.9%), tridecene (3.2%) tridecane (2.7%), pentadecene (2.5%), pentadecane (3.4%) dodecanoic acid (7.5%).

heptadecene (0.4%), heptadecane (0.9%), 2-heptadecanone (2.3%), hexadecanoic acid (11.5%), 2- nonadecanone (0.4%) and numerous unidentified materials. The products were essentially free of aromatic hydrocarbons.

Example 2 Calcium hydroxide at 200°C with separate streams

[0128] A slurry (300 mL) of 18 g of microalgae plus 6 g of calcium hydroxide was heated to 200°C for 30 minutes, then cooled and filtered to recover 11.38 g solid. This was pyrolysed to give 1.82 g of oil, which comprised: toluene (16.3%), ethyl benzene (2.2%), xylene (2.8%), styrene (5.6%), naphthalene (3.2%), nonene (0.9%), nonane (0.8%), decene (0.8%), undecene (0.74%), tridecene (1.1%), tridecane (1%), tetradecene (1.5%), tetradecane (1.1%), pentadecene (0.9%), pentadecane (1%), heptadecene (0.9%), heptadecane (2.5%), 2-heptadecanone (5.2%), phytol (1.9%), and numerous unidentified components.

[0129] To the filtrate, a solution of ferric sulphate (3 g) was added and following filtration 1.33 g of solids obtained. The subsequent filtrate was then heated for 30 minutes at 400°C, cooled, and 1.43 g of oil was obtained, which comprised: toluene (5.7%), xylene (9.9%), styrene (9.9%), pyrrole (9%), N-ethyl pyrrole (3.4%), tetramethyl pyrrole (2%), an N-alkykted 2-pyrrolidinone (4.1%) and numerous unidentified components.

[0130] When this solution was acidified to pH 1, 0.047 g of further material was extracted, which comprised: 2-methyl propanoic acid (6.8%), butanoic acid (19.6%), 3-methyl butanoic acid (4.5%), 2-methyl butanoic acid (9.7%), 4-methyl pentanoic acid (5.2%), cyclop entanone (0.2%), methyl pyrazine (0.8%), 2,3-dimethyl cyclopent-2-en-l-one (2.3%), N-ethyl-2-pyrrolidinone (8.3%), N-butyl-2-pyrrolidinone (4.3%), N-pentyl-2-pyrrolidinone (4.3%) and numerous unidentified components. [0131] On making this solution basic to pH 14, a further 0.09 g of material was obtained, which comprised: 2-methyl cyclopent-2-en-l-one (1.4%), 2,3-dimethyl cyclopent-2-en-l-one (1.9%), 3-methyl piperidine (8.6%), 1,3-dimethyl piperidine (2.7%), 2,6-dimethyl piperidine (2.1%), 3-methyl pyridine (0.8%), 2,5-dimethyl pyrazine (2.1%), trimethyl pyrazine (2%), N-methyl-2-pyrrolidinone (4%), N-ethyl-2-pyrrolidinone (9.2%), N-butyl-2-pyrrolidinone (3.9%), N-pentyl-2-pyrrolidinone (7.1%) and numerous unidentified components.

Example 2 Calcium hydroxide at 250°C

[0132] The filtration residue obtained after reacting a slurry of microalgae (18.6 g estimated dry weight) with Ca(OH), (1.86 g) at 250°C was pyrolysed to yield an oil (2.8 g) which comprised:

toluene (9.9%), ethyl benzene (2.9%), xylene (3.8%), styrene (4.6%), nonene (3.1%), nonane (2%), decene (1.9%), decane (1.5%), undecene (3.1%), undecane (2.1%), dodecene (2.9%), dodecane

(1.3%), tridecene (2.1%), tridecane (1.4%), tetradecene (2.3%), pentadecene (1.5%), heptadecene (0.9%), heptadecane (2%), 2-heptadecanone (2.8%), indole (2.3%), 3-methyl indole (2.2%), and numerous unidentified materials.

[0133] The aqueous solutions gave 0.51 g extractible oil, which comprised: dimethyl disulphide (3%), cyclopentanone (1.2%), methyl pyrazine (13.5%), 2-methyl cyclopent-2-en-l-one (4.5%), 2,5- dimethyl pyrazine (18.6%), 2-ethyl-3-methyl pyrazine (2.9%), trimethyl pyrazine (9.9%), 3-ethyl-2,5- dimethyl pyrazine (4.7%), trimethyl hydantoin (1.5%), 3,6-diisobutyl-2,5-piperazinedione (2.5%) and numerous unidentified components. After acidification to pH 1, 0.61 g of material was recovered, which contained butanoic acid (29%), 2-methyl butanoic acid (13.6%), 4-methyl pentanoic acid (7.2%), methyl pyrazine (7.4%), 2,5-dimethyl pyrazine (4.4%), and numerous unidentified components. After adjusting the pH to 14, 0.21 g of material was recovered, which comprised: 2- methyl pipefidine (=15%), methyl pyrazine (7.1%), 2,5-dimethyl pyrazine (6.9%), trimethyl pyrazine (3%), 2-piperidinone (2.1%) and numerous unidentified components.

Example 3 Calcium hydroxide at 250°C with separate streams

[0134] A slurry (300 mL) of 18 g of microalgae plus 9 g of calcium hydroxide was heated to 250°C for 30 minutes, then cooled and filtered to recover 12.38 g solid. Upon pyrolysis, 1.42 g oil comprised: toluene (21.7%), ethyl benzene (3.2%), xylene (3.3%), styrene (4.9%), naphthalene (2.8%) , nonene (1%), npnane (1.4%), tridecene (1.5%), tridecane (1.1%), tetradecene (1.5%), pentadecene (1.3%), pentadecane (1%), heptadecene (1%), heptadecane (1.1%), 2-heptadecanone (5.1%), 2-nonadecanone (1.2%) and numerous unidentified compounds. [0135] The aqueous solution (pH =9.5) was acidified to pH 1, and a sample run through a GCMS, and the volatile fraction contained acetic acid (25.4%), propanoic acid (6.5%), 2-methyl propanoic acid (7.6%), butanoic acid (18.5%), 3-mefhyl butanoic acid (4.3%), 2-methyl butanoic acid (6.9%), 2,5-dimethyl pyrazine (3.8%), trimethyl pyrazine (3.5%), and numerous unidentified components. [0136] Ferric sulphate (3 g) dissolved in water was added to the acidified filtrate, and the pH gradually made basic until all ferric salts had precipitated. The ferric salts were then filtered, and the remaining solution heated to 400°C for 30 minutes. After cooling the solution was extracted with dichlorome thane, then acidified to pH 1 and extracted with dichloromethane, then the solution was made basic to pH 14 and extracted with dichloromethane. The yields of oil from these three extractions following solvent removal were 1.67 g, 0.28 g and 0.03 g respectively.

[0137] The ferric precipitate was pyrolysed, but very little distillate (30 mg) was collected, although there was considerable smoke.

[0138] The first extract from the supercritical run comprised: N-methyl pyrrole (3.3%), N-ethyl pyrrole (1.7%), 2,3,4,5-tetramethyl pyrrole (1.1%), toluene (2.3%), xylene (3.9%), styrene (4.8%), N- ethyl 2-pyrrolidinone (3.4%), N-propyl 2-pyrrolidinone (4.1%), N-butyl 2-pyrrolidinone (5.1%), 3- methyl indole (3.6%), heptadecane (2.4%), 2-heptadecanone (1.4%) and numerous unidentified compounds.

[0139] The oil from the pH=l extract comprised 2-methyl propionic acid (5.3%),

cyclopentanone (0.9%), 3-methyl butanoic acid (5.6%), 2-methyl butanoic acid (7%), methyl pyrazine (0.7%), hexanoic acid (3.6%), 4-methyl pentanoic acid (9.3%), 2,5-dimethyl pyrazine (0.9%), 2,3-dimethyl cyclopent-2-en-l-one (0.8%), N-ethyl 2-pyrrolidinone (6%), N-propyl 2- pyrrolidinone (2.3%), N-butyl 2-pyrrolidinone (3.3%) and numerous unidentified compounds.

[0140] The major identified compound from the pH 14 extract was N-methyl piperidine.

Example 4. Calcium hydroxide at 275°C with separate streams [0141] A slurry (300 mL) of 18 g of microalgae plus 1.8 g of calcium hydroxide was heated to 275°C for 30 minutes, then cooled and filtered to recover 8.08 g solid. The solid was pyrolysed to give 1.90 g oil, which comprised: toluene (18.3%), ethyl benzene (3.1%), xylene (3.4%), naphthalene (1.5%), nonene (0.8%), undecene (1.2%), dodecene (1.3%), tridecene (1.8%), tridecane (1.6%), tetradecene (1.8%), tetradecane (1%), pentadecene (1.7%), pentadecane (1.5%), heptadecene (1.5%), heptadecane (3%), 2-heptadecanone (5.2%), and numerous unidentified compounds.

[0142] Extraction of the solution with methylene chloride, followed by the removal of the solvent provided 0.64 g of oil, which comprised: pyrimidine (2.7%), cyclopentanone (0.6%), 2- methyl cyclopent-2-en-l-one (1.9%), methyl pyrazine (9.8%), 2,5-dimethyl pyrazine (6.9%), ethyl pyrazine (7.1%), 2 -ethyl-3-methyl pyrazine (3.3%), trimethyl pyrazine (8%), 2-ethyl-3,6-dimethyl pyrazine (3.8%), tetramethyl pyrrole (0.5%), piperazinediones (14.6%), pyrrolopyrazine diones (5.6%) and numerous unidentified compounds.

[0143] The filtrate was then heated to for 30 minutes at 350°C in the presence of 0.6 g kaolin, cooled, extracted with methylene chloride to give 1.76 g of oil, which comprised: propanoic acid (2.8%), butanoic acid (3%), 3-methyl butanoic acid (6.7%), 4-methyl pentanoic acid (<9.5%), benzene propanoic acid (4.1%), xylene (1.1%), 2-methyl cyclopent-2-en-l-one (2.4%), 2,5-dimethyl pyrazine (4.8%), trimethyl pyrazine (2%), ethyl dimethyl pyrazine (3.5%), tetramethyl pyrrole (1.1%), N-methyl succinimide (3.9%), trimethyl hydantoin (4.1%), 2-piperidinone (6.3%), heptadecane (0.7%) and numerous unidentified compounds.

[0144] The aqueous fraction also contained in relative proportions xylene (0.7%), acetic acid (34.8%), butanoic acid (5.7%), benzene propanoic acid (3.8%), N-methyl 2-pyrrolidinone (3.9%), 2- pyrrolidinone (7.3%), 2-piperidinone (8.1%) and numerous unidentified compounds.

Example 5. Calcium hydroxide at 275°C with separate streams

[0145] A slurry (300 mL) of 18 g of microalgae plus 7.5 g of calcium hydroxide was heated to 275°C for 30 minutes, then cooled and filtered to recover 14.14 g solid. The solid was pyrolysed to give 2.12 g oil, which comprised: toluene (24.9%), ethyl benzene (5%), xylene (3.3%), styrene (4.8%), nonene (1.2%), nonane (2.8%), decene (1.6%), decane (1.4%), undecene (1.4%), undecane (1.4%), dodecene (1.9%), dodecane (2.8%), tridecene (3.2%), tridecane (2.4%), tetradecene (2.7%), tetradecane (1.4%), pentadecene (1.3%), pentadecane (1.4%), heptadecane (1.2%), 2-heptadecanone (2.3%), and numerous unidentified compounds. [0146] The nitrate was then heated to for 30 minutes at 350°C in the presence of 0.4 g of kaolin, cooled, extracted with methylene chloride to give 1.1 g of oil, which comprised: dimethyl disulphide (1.9%), toluene (1.1%), xylene (1.9%), styrene (6%), 2-methyl pyrazine (2%), 2,5-dimethyl pyrazine (2.6%), trimethyl pyrazine (4.3%), and numerous unidentified compounds.

The aqueous fraction also contained in relative proportions cyclopentanone (3.9%), acetic acid (17.1%), 2-methyl propionic acid (6.4%), butanoic acid (9%), 2-methyl cyclopent-2-en-l-one (2.5%), methyl pyrazine (3.2%), 2,5-dimethyl pyrazine (2%), trimethyl pyrazine (3.2%), and numerous unidentified compounds.

Example 5 Calcium hydroxide at 300°C

[0147] The filtration residue obtained after reacting 18.6 g microalgae with 1.86 g Ca(OH)₂ at 300°C were pyrolysed to yield an oil (3.23 g) which comprised toluene (9%), ethyl benzene (3.4%), xylene (3.8%), styrene (4.2%), nonene (3%), nonane (1.6%), decene (2.4%), decane (1.4%), undecene (3.1%), undecane (1.2%), dodecene (3.1%), dodecane (1.5%), tridecene (1.9%), tridecane (1.1%), tetradecene (2.2%), pentadecene (2.4%), heptadecene (1%), heptadecane (1.8%), heptadecanone (1.5%), indole (1.8%), 3-methyl indole (2.3%), hexadecanamide (1.2%) and numerous unidentified materials.

The extracts from the aqueous solution gave 0.44 g oil comprising: N-methyl pyrrole (5.1%), N- ethyl pyrrole (1.1%), dimethyl disulphide (1.5%), cyclopentanone (1.4%), methyl pyrazine (12%), 2- methyl cyclopent-2-en-l-one (2.4%), 2,5-dimethyl pyrazine (9.5%), ethyl pyrazine (6.9%), 2-ethyl-3- methyl pyrazine (4.2%), trimethyl pyrazine (9.5%), 2,3-dimethyl cyclopent-2-en-l-one (1.1%), 2- ethyl-3,6-dimethyl pyrazine (3.6%), 3,6-diisobutyl-2,5-piperazinedione (0.6%), condensed pyrazines (3.3%) and numerous unidentified components. After acidification to pH 1, 6.9 g of material was recovered, which contained 2-methyl propionic acid (6.4%), butanoic acid (19.8%), 3-methyl butanoic acid (7.7%), 2-methyl butanoic acid (10.0%), pentanoic acid (4.8%), 4-methyl pentanoic acid (15.9%), methyl pyrazine (3.2%), ethyl pyrazine (1.5%), trimethyl pyrazine (0.6%), 2- piperidinone (1.3%), and numerous unidentified components. After adjusting the pH to 14, 2.5 g of material was recovered, which comprised: 2- or 3-methyl piperidine (28.1%), methyl pyrazine (2.8%), 2,5-dimethyl pyrazine (4.6%), ttimethyl pyrazine (3.2%), 2-piperidinone (3.4%) and numerous unidentified components.

Example 6 Calcium hydroxide at 350°C

[0148] The filtration residue obtained after reacting a slurry of microalgae (18.6 g estimated dry weight) with Ca(OH)₂ (3.6 g) at 350°C was pyrolysed to yield an oil (2.0 g) which comprised toluene (13.5%), ethyl benzene (5.1%), xylene (4.3%), styrene (8.9%), nonane (2.8%), decene (3.8%), decane (2.7%), undecene (2.5%), undecane (1.5%), dodecane (1.4%), tridecene (1.9%), tridecane (1.3%), tetradecene (1.7%), tetradecane (1.2%), pentadecene (1.1%), pentadecane (1.9%), heptadecane (1.2%), heptadecanone (1.5%), pyrrole (1.1%), and numerous unidentified materials. [0149] The aqueous solution gave 0.47 g of extractible oil, comprising: N-methyl pyrrole (3.8%), dimethyl disulphide (4.3%), cyclopentanone (1.4%), methyl pyrazine (4.3%), 2-methyl cyclopent-2-en-l-one (2.4%), 2,5-dimethyl pyrazine (4.6%), ethyl pyrazine (1-8%), 2-ethyl-6-methyl pyrazine (3.7%), ttimethyl pyrazine (5.4%), 2,3-dimethyl cyclopent-2-en-l-one (2.2%), N-ethyl-2- pyrrolidinone (2.1%), 2-piperidinone (3.2%), N-butyl-2-pyrrolidinone (3.6%), condensed pyrazines (1.8%) and numerous unidentified components. After acidification to pH 1, 0.5 g of material was recovered, which contained butanoic acid (4.3%), 3-methyl butanoic acid and 2-methyl butanoic acid (9.6%), pentanoic acid (4.3%), 4-methyl pentanoic acid (10.9%), benzene propionic acid (8%), methyl pyrazine (4.3%), 2-pyrrolidinone (1.1%), 2-piperidinone (5.1%), and numerous unidentified components. After adjusting the pH to 14, 0.16 g of material was recovered, which comprised: nonane (1.6%), decane (3.1%), undecane (0.7%), N-methyl piperidine (22.7%), methyl pyrazine (2.8%), 2,5-dimethyl pyrazine (4%), ttimethyl pyrazine (2.5%) and numerous unidentified components.

Example 7 Hydt othermal eaction of a residue from filter

[0150] To 22.2 g of the algae residue resulting from filtering a run at 300°C with 10% calcium hydroxide was added a further 2.4 g of calcium hydroxide and this was dispersed in 250 g of water and heated to 400°C for 30 minutes. On cooling, extracting with methylene chloride, then evaporating the solvent, 7.01 g of oil was recovered. The aqueous solution was acidified and further extracted to give 0.45 g of extract. The components of the extracts were:

[0151] The oil comprised toluene (12.8%), ethyl benzene (13.3%), xylene (3%), nonane (1.8%), decane (1.8%), 2,3-dimethylcyclopent-2-en-l-one (1.8%), undecene (1.4%), undecane (3.2%), p-ethyl phenol (1.1%), dodecane (1.7%), tridecene (0.6%), tridecane (1.7%), tetradecene (0.6%), pentadecene (1.1%), pentadecane (3.3%), heptadecane (5.8%), eicosane (4.5%), hexadecanamide (1.1%).

[0152] The extract from the acidified aqueous solution comprised acetic acid (36.5%), propionic acid (7.6%), 2-methyl propionic acid (6.3%), butanoic acid (8.1%), 3-methyl butanoic acid (6.3%), 2-methyl butanoic acid (8.9%), hecxanoic acid (0.7%), heptadecane (0.7%), 3,6-diisobutyl- 2,5-piperazinedione (0.5%) and numerous unidentified components.

Example 8 Ferric oxide

[0153] When microalgae (18.6 g) were reacted with ferric oxide (1.86 g) at 250°C, however, and the resultant solids filtered, then pyrolysed, 3.29 g of oil was recovered, which comprised toluene (10.9%), ethyl benzene (3%), styrene (6.1%), decene (4.3%), decane (1.9%), undecene (4.4%), undecane (2.3%), dodecene (0.8%), dodecane (2.4%), tridecene (3.9%), tridecane (2.1%), tetradecene (2.2%), tetradecane (1.7%), pentadecene (2.6%), pentadecane (2.5%), heptadecene (0.7%), heptadecane (1.4%), pyrrole (1.5%), indole (1.8%), oleic acid (1.3%), and numerous unidentified materials. [0154] The aqueous solution gave 1.5 g of volatile materials, comprising 0.81 g neutral extract, 0.45 g at pH 1, and a further 0.25 g of extract when the solution was adjusted to pH 14.

[0155] The neutral solution comprised: xylene (0.61%), trimethyl benzene (3.9%), nonane (0.9%), undecane (1.6%), 2-methyl cyclopent-2-en-l-one (2.4%), methyl pyrazine (7.5%), 2,5- dimethyl pyrazine (14.8%), trimethyl pyrazine (7.7%), 2-ethyl-3,6-dimethyl pyrazine (3.6%), 2- piperidinone (0.9%), condensed piperazinediones (3.5%), condensed pyrazinediones (2.4%) and numerous unidentified compounds.

[0156] The acid solution comprised: 2-methyl propanoic acid (2.8%), butanoic acid (20.3%), 2- methyl butanoic aicd (9%), pentanoic acid (3.5%), 4-methyl pentanoic acid (9.8%),

benzenepropanoic acid (5.8%), oleic acid (1.2%), 2,5-dimethyl pyrazine (0.5%), 2-piperidinone (3.9%), nonane (0.2%), undecane (0.6%), pentadecene (0.8%), condensed piperazinediones (2%), condensed pyrazinediones (2.3%) and numerous unidentified compounds.

[0157] The basic solution comprised: methyl piperidines (16.7%), methyl pyrazine (2.7%), 2,5- dimethyl pyrazine (1.5%), xylene (1%), nonane (2%), trimethyl benzene (5.9%), decane (3.9%), undecane (1.3%) and numerous unidentified compounds. Example 9 Aluminium hydroxide

[0158] A sample of microalgae ( 18.6 g/300 mL) was treated with 1.86 g aluminium hydroxide, made by neutralizing a solution of alum with ammonia solution to make the pH equal to 8.4, and heated to 250°C. After cooling, the solids were filtered, and when these were pyrolysed, 4.05 g of oil were recovered, which comprised toluene (21.9%), ethyl benzene (4.3%), xylene (3.6%), styrene (7.6%), octene (3.7%), nonane (1%), decene (3.2%), decane (1.5%), undecene (3.1%), undecane (2.4%), dodecane (2.2%), tridecene (2%), tridecane (0.9%), tetradecene (1.3%), tetradecane (0.5%), pentadecene (1.8%), pentadecane (1.2%), heptadecene (0.4%), heptadecane (0.8%), pyrrole (3.2%), hexadecanamide (0.8%), and numerous unidentified materials. The aqueous solution gave 0.80 g of volatile materials, and approximately 9.7 g of polymeric organic material dissolved in the aqueous solution.

Example 10. Zinc oxide at 200°C

[0159] A sample of microalgae ( 18.6 g/300 mL) was treated with zinc oxide (3 g) and heated to 200°C. After cooling, the solids were filtered, to give 9.6 g residue. There was no visible oil separated. When the residues were pyrolysed, 0.23 g of oil were recovered, which comprised toluene (9.2%), ethyl benzene (2.3%), xylene (2.9%), styrene (5.2%), naphthalene (4.2%), nonane (0.7%), decene (0.7%), tridecene (0.7%), tetradecene (1%), pentadecene (2.3%), pentadecane (0.9%), heptadecene (1.5%), heptadecane (2.2%), tetramethyl hexadecen-3-ols (at least 2 isomers, at least 9%), 3-eicosyne (4%), oleic acid (4.9%), and numerous unidentified materials. [0160] The filtrate (pH 7.6) gave approximately 0.1 g oil, which comprised: approximately 2.4 % methyl and dimethyl pyrazine, approximately 18% of pyrrolopyrazine diones, 4.4% of a piperazinedione and several unidentified compounds.

[0161] The aqueous solution acidified to approximately pH 1 gave an extract that comprised: acetic acid (16%), propanoic acid (5.5%), 2-methyl propanoic acid (9.1%), butanoic acid (20.5%), 3- methyl butanoic acid (4.6%), 2-methyl butanoic acid (8%), 4-methyl pentanoic acid (4.2%), trimethylamine (3.1%), methyl pyrazine (2.1%), 2,5-dimethyl pyrazine (5.3%), 2-ethyl-6-methyl pyrazine (2.1%), trimethyl pyrazine (6.3%), 3-ethyl-2,5-dimethyl pyrazine (3.4%) and several unidentified compounds.

[0162] When the solution was made basic to pH 14, the extract comprised: pyrimidine (2.3%), 4,6-dimethyl pyrimidine (7.2%), methyl pyrazine (6.6%), 2,5-dimethyl pyrazine (6.3%), 2-ethyl-6- methyl pyrazine (2.9%), trimethyl pyrazine (12%), 3-ethyl-2,5-dimethyl pyrazine (3.2%), 2- piperidinone (4%) and several unidentified compounds. Example 11 Zinc Oxide at 250°C

[0163] A sample of microalgae ( 18.6 g/300 mL) was treated with zinc oxide (1.8 g) and heated to 250°C. After cooling, the solids were filtered, and when these were pyrolysed, 2.19 g of oil were recovered, which comprised toluene (9.7%), ethyl benzene (3.9%), xylene (3.8%), naphthalene (2.5%), nonene (2.7%), nonane (2.2%), decene (2.6%), decane (2%), undecene (2.3%), undecane

(2%), dodecane (1.7%), tridecene (1.5%), tridecane (1.3%), tetradecene (1.3%), tetradecane (0.8%), pentadecene (1.7%), pentadecane (1.8%), heptadecene (0.8%), heptadecane (1.4%), and numerous unidentified materials.

[0164] The filtrate was then extracted with methylene chloride, and when the methylene chloride was evaporated, 0.44 g oil was obtained, which comprised: pyrimidine (1.2%),

cyclopentanone (0.4%), 2-methyl cyclopent-2-en-l-one (2.8%), 2-methyl pyrazine (6.1%), 2,5- dimethyl pyrazine (5.8%), ethyl pyrazine (4.5%), 2-ethyl-3-methyl pyrazine (2.9%), trimethyl pyrazine (6.7%), 2-piperidinone (1.5%), 3-isobutylhexahydropyrrolo[l,2-a]pyrazine-l-4-dione (10.5%), 3- benzyl-6-isopropylpiperazine-2,5-dione (3.2%), hexahydro-3-(phenylmethyl)-pyrrolo[l,2-a]pyrazine- 1,4-dione (2.5%) and numerous unidentified materials.

[0165] The pH of the filtrate was then made equal to 1, and a further 0.78 g of material was extracted, which comprised: pyrimidine (3.1%), propanoic acid (11.8%), butanoic acid (26.2%), 3- methyl butanoic acid (4.5%), 2-methyl butanoic acid (14.1%), 2-methyl cyclopent-2-en-l -one (2%), ethyl pyrazine (1%) and numerous unidentified materials. [0166] The pH of the filtrate was then made equal to 1, and a further 0.29 g of material was extracted, which comprised: pyrimidine (14.1%), 2-methyl piperidine (11.6%), methyl pyrazine (12.9%), 2,5-dimethyl pyrazine (14.8%), trimethyl pyrazine (6%), and numerous unidentified materials.

Example 12 Zinc Oxide at 250°C [0167] A sample of microalgae ( 18.6 g/300 mL) was treated with zinc oxide (6 g) and heated to 250°C. After cooling, the solids were filtered, and when these were heated for 30 minutes at 350°C under pressure in the presence of 250 mL water, 1.67 g of oil were recovered, which comprised toluene (5.2%), xylene (4.8%), styrene (0.9%), nonene (0.7%), tridecene (1.3%), tetradecene (1.6%), pentadecane (1.6%), pentadecene (14.7%), heptadecene (1.9%), heptadecane (4.5%), tetramethyl hexadecenes (10.8%), and numerous unidentified materials. [0168] The filtrate was then extracted, to give 0.57 g of oil, which comprised pyrimidine (1%), methyl pyrazine (4.6%), 2,5-dimethyl pyrazine (5.1%), ethyl pyrazine (4%), 2-ethyl-3-methyl pyrazine (3.1%), trimethyl pyrazine (6.5%), 2,5-dimethyl-3-ethyl pyrazine (4.7%), trimethyl hydantoin (0.5%),

2- piperidinone (1.3%), 2-methylcyclopent-2-en-l-one (2.7%), 3-isobutylhexahydropyrrolo[l,2- a]pyrazine-l-4-dione (9.4%), 3-benzyl-6-isopropylpiperazine-2,5-dione (2.8%), and numerous unidentified compounds.

[0169] The extracted filtrate was then heated to 350°C for 30 mins in the presence of 0.5 g kaolin, and after cooling the solution had a pH of 3.8, and extraction with methylene chloride gave 1.15 g oil, which comprised: dimethyl disulphide (1.4%), toluene (1.1%), 2-methyl propanoic acid (2.8%), butanoic acid (18.5%), 3-methyl butanoic acid (5.3%), 2-methyl butanoic aicd (7.5%), 4- methyl pentanoic aicd (7.5%), cyclopentanone (0.4%), 2-methyl cyclopent-2-en-l-one (0.8%), 3,3- dimethyl cyclopent-2-en-l-one 0.8%), methyl pyrazine (1.1%), trimethyl pyrazine (0.5%), N-methyl succinknide (0.5%), trimethyl hydantoin (2.3%) and several unidentified compounds.

[0170] The extraction was not complete because the aqueous solution contained the following, in relative concentrations: acetic acid (28%), 2-methyl propanoic acid (5.3%), butanoic acid (20.5%),

3- methyl butanoic acid (2.6%), 2-methyl butanoic aicd (2.8%), benzene propanoic acid (4.6%), N- methyl succinimide (0.9%), trimethyl hydantoin (0.5%), 2-piperidinone (4.3%), and several unidentified compounds.

Example 13 Cupric oxide [0171] A sample of microalgae ( 18.6 g/300 mL) was treated with cupric oxide (1.86 g) and heated to 250°C. After cooling, the solids were filtered, and when these were pyrolysed, 1.57 g of oil were recovered, which comprised toluene (8%), ethyl benzene (2.8%), xylene (2.8%), styrene (3.8%), octene (2%), nonene (2.6%), nonane (1.1%), decene (2.4%), decane (1.4%), undecene (3.3%), undecane (1.8%), dodecene (4.9%), dodecane (1.2%), tridecene (2.7%), tridecane (1.1%), tetradecene (1.9%), pentadecene (2.6%), pentadecane (1.7%), heptadecane (1.4%), 2-heptadecanone (2.8%), 3-eicosyne (1.8%), oleic acid (1.4%), hexadecanamide (2.2%), p-cresol (3.8%), indole (1.8%), 3-methyl indole (1.6%), and numerous unidentified materials. The aqueous solution contained 3.6 g of polymeric organic material, gave 0.63 g of volatile materials.

[0172] A sample of microalgae ( 18.6 g/300 mL) was treated with cupric oxide (1.86 g) and heated to 300°C. After cooling, the solids were filtered, giving 8.55 g of solids and when these were pyrolysed, 1.37 g of oil were recovered, which comprised toluene (6.8%), ethyl benzene (1.5%), xylene (1.4%), styrene (2.9%), naphthalene (3.2%), tridecene (1.1%), tridecane (0.9%), tetradecene (1.1%), tetradecane (1.2%), pentadecene (3.5%), pentadecane (1.6%), heptadecene (2.2%), heptadecane (3.4%), and numerous unidentified materials. The aqueous solution contained 2.6 g of polymeric organic material, gave 0.93 g of volatile materials.

Example 14 Magnesium oxide at 250°C [0173] A sample of microalgae ( 18.6 g/300 mL) was treated with magnesium oxide (1.8 g) and heated to 250°C. After cooling, the solids were filtered, and when these were pyrolysed, 3.22 g of oil were recovered, which comprised toluene (6.9%), ethyl benzene (2.3%), xylene (2.4%), styrene (3.3%), nonene (2.2%), nonane (1.5%), decene (2.2%), decane (1.1%), undecene (2.3%), undecane (1.9%), dodecene (3.7%), dodecane (1.1%), tridecene (1.8%), tridecane (1.3%), tetradecene (2%), pentadecene (1.4%), heptadecane (1.1%), 2-heptadecanone (2.8%), oleic acid (3.8%), p-ethyl phenol (0.9%), pyrrole (2%), indole (1.9%), 3-methyl indole (1.6%), and numerous unidentified materials. The aqueous solution gave 0.82 g of volatile materials, and approximately 9.8 g of polymeric organic material dissolved in the aqueous solution.

[0174] A repeat of this reaction gave a yield of pyrolysed oil of 1.77 g, which comprised toluene (32.5%), ethyl benzene (3.2%), xylene (3.8%), styrene (6.7%), naphthalene (5.3%), nonene (1.4%), nonane (1.1%), dodecane (0.5%), tridecene (0.5%), tridecane (0.5%), tetradecene (0.6%), tetradecane (0.2%), pentadecene (0.7%), pentadecane (0.5%), heptadecane (1.1%), 2-heptadecanone (3.1%), and numerous unidentified materials.

[0175] The filtrate was then heated to 350°C for 30 minutes in the presence of 0.5 g of kaolin, and after cooling, the solution was extracted with methylene chloride, and this extract, following evaporation, gave 1.23 g of oil which comprised dimethyl disulfide (3.6%), toluene (2.2%), xylene (2.1%), styrene (5.8%), 2-methyl cyclopent-2-en-l-one (1%), pyrrole (5.1%), methyl pyrazine (1.8%), 2,5-dimethyl pyrazine (1.8%), trimethyl pyrazine (3.1%), N-ethyl 2-pyrrolidinone (1.6%), and numerous unidentified materials. [0176] The aqueous solution had unextracted material in the following ratios: acetic acid

(18.1%), piperidine (5.2%), butanoic acid (5.2%), N-methyl acetamide (4.2%), N-ethyl acetamide (4.3%), N-methyl succinimide (1%), N-methyl-2-pyrrolidinone (2.3%), 2-pyrrolidinone (2.2%), 2- piperidinone (8.9%) and numerous unidentified compounds.

Example 15 Magnesium oxide at 250°C [0177] A sample of microalgae ( 18.6 g/300 mL) was treated with magnesium oxide (3.72 g) and heated to 250°C. After cooling, the solids were filtered, and when these were pyrolysed, 2.97 g of oil were recovered, which comprised toluene (16.2%), ethyl benzene (3.8%), xylene (4.9%), naphthalene (5.1%), styrene (8.4%), nonene (2.3%), nonane (1.2%), decene (2.3%), decane (1.1%), undecene (1.4%), undecane (1.4%), dodecane (0.9%), tridecene (1.3%), tridecane (1%), tetradecene (1.8%), tetradecane (1%), pentadecene (1.1%), pentadecane (0.9%), heptadecane (1.1%), tetramethylhexadec-2-ene (4.3%), 2-heptadecanone (5.1%), 2-nonadecanone (1%), oleic acid (2.3%), 3-methyl indole (1.1%), and numerous unidentified materials. The aqueous solution contained approximately 8.9 g of polymeric organic material dissolved in the aqueous solution.

Example 17 Magnesium oxide at 300°C

[0178] A sample of microalgae ( 18.6 g/300 mL) was treated with magnesium oxide (13.5 g) and heated to 300°C. After cooling, the solids were filtered, and when these were pyrolysed, 1.5 g of oil were recovered, which comprised toluene (4.4%), ethyl benzene (2.6%), xylene (2.8%), substituted benzene (5.4%) decene (1.5%), undecene (1.7%), undecane (1.5%), dodecene ? (5%), dodecane (1.2%), tridecene (2%), tridecane (1.2%), tetradecene (2.5%), tetradecane (1.2%), pentadecene (2.2%), pentadecane (1.5%), heptadecane (2.8%), 2-heptadecanone (5.4%), 2- nonadecanone (1.1%), oleic acid (3.3%) and numerous unidentified materials.

Example 18 Magnesium oxide at 330°C

[0179] A sample of microalgae ( 18.6 g/300 mL) was treated with magnesium oxide (13.5 g) and heated to 330°C. After cooling, the solids were filtered, and when these were pyrolysed, 0.4 g of oil were recovered, which comprised toluene (2.2%), ethyl benzene (2.8%), xylene (3%), nonene (1.6%), nonane (1.5%), decene (2.5%), decane (1.5%), undecene (2.9%), undecane (1.6%), dodecene (5%), dodecane (1.8%), tridecene (3.2%), tridecane (2.3%), tetradecene (4.2%), tetradecane (1.8%), pentadecene (1.9%), pentadecane (1.8%), heptadecene (2.8%), heptadecane (2.4%), 2-heptadecanone (6.2%), 2-nonadecanone (2.1%), and numerous unidentified materials.

Example 19 Chicken wastes with calcium hydroxide [0180] 60 g of ground chicken together with 12 g of calcium hydroxide were heated to 250°C for 30 minutes, then cooled and filtered, giving 10 g of solid and 5.5 g oil.

[0181] The recovered oil comprised dimethyl disulphide (6.9%), xylene (0.9%), nonane (1.2%), decane (2.7%), undecane (1.8%), pyrrole (8.9%), piperidine (10.4%), N-methyl pyrrole (0.5%), N- ethyl pyrrole (6.5%), indole (2.7%), condensed piperazines (1.7%), 3,6-diisobutyl-2,5- piperazinedione (0.5%) and numerous unidentified components. [0182] The lOg of filtered solid were reacted with a further 1.4 g of calcium hydroxide in 300 mL of water at 400°C for 30 minutes, then cooled and filtered, giving 6.7 g of solids. 1.1 g of oil was recovered, which comprised toluene (3%), xylene (1.3%), styrene (2.2%), nonene (0.9%) decane (2%), undecene (0.9%), undecane (2%), tridecane (0,7%), tetradecene (1.2%), pentadecene (1.3%), pentadecane (1.2%), heptadecene (4.8%), heptadecane (2.6%), nonadecene (6.9%), 2-heptadecanone (6.8%), oleic acid (10.8%), 2-nonadecanone (3.3%) and numerous unidentified components.

[0183] The extracted filtrate from the reaction with chicke containing 11.8 g of dissolved solid in 300 mL water was reacted for 30 minues at 400°C, then cooled. The solution contained 4.2 g solid, and yielded 1.64 g oil. [0184] The recovered oil comprised dimethyl disulphide (3.3%), ethyl benzene (3.4%), xylene ' (4.1%), styrene 6.5%, decane (3.7%), undecane (1.8), 4-ethyl phenol (3.6%), 2-methyl-N-(2- methylbutylidene)-l-butanamine (2.5%), N-methyl 2-pyrrolidinone (3.4%), N-ethyl 2-pyrrolidinone (5.1%), N-butyl 2-pyrrolidinone (2.2%), N-ethyl pyrrole (2.5%), indole (0.5%), 3-methyl indole (1.9%) and numerous unidentified components. [0185] The remaining aqueous fraction contained the following volatiles (0.51 g): acetic acid (11.3%), 3-methyl piperidine (9%), pyrrolidine (4.1%), piperidine (6.9%), N-methyl acetamide (2.8%), N-ethyl acetamide (1.6%), %), 2-pyrrolidinone (4.5%), N-methyl 2-pyrrolidinone (12.1%), . N-ethyl 2-pyrrolidinone (6.8%), 2-piperidinone (3.8%), N-butyl 2-pyrrolidinone (2.5%), 4- hydroxybenzeneethanol (4%) and numerous unidentified components. Example 20 Pyrolysis of microalgae with 50% by weight lime

[0186] A sample of microalgae (3.33 g) intimately mixed with calcium hydroxide (1.67 g) was pyrolysed and 0.88 g g of pyrolysate was collected, with 3.04 g of residual solid collected (leaving 1.08 g unaccounted. This will include adventitious water from the microalgae which had been air- dried, but not dessicated.) The pyrolysate was analysed by GC-MS, and was found to contain: 3- methylbutyronitrile (2.8%), 4-methylvaleronitrile (3.6%), methyl isobutyl ketone (2.5%), toluene (13.6%), xylene (3.3%), styrene (4.6%), pyrrole (5.3%), 3-methylpyrrole (2.3%), indole (4.4%), 3- methylindole (2.7%), p-cresol (2%), p-ethylphenol (1.7%), nonene (1.6%), nonane (0.9%), decene (1.2%), undecene (1.8%), undecane (1.6%), dodecane (1.6%), tridecene (1.4%), tridecane (0.9%), tetradecene (1.9%), pentadecene (1%), pentadecane (1.3%), heptadecene (0.6%), heptadecane (1.2%), 2-heptadecanone (4.2%), oleic acid (1.3%) and numerous unidentified components. Example 21 Pytolysis of microalgae with 50% by weight MgO

[0187] A sample of microalgae (3.56 g) intimately mixed with magnesium oxide (1.67 g) was pyrolysed and 0.37 g of pyrolysate was collected. The pyrolysate was analysed by G CMS, and was found to contain: 4-methylvaleronitrile (3.8%), toluene (6.4%), ethylbenzene (2.6%), xylene (2.3%), styrene (6.5%), naphthalene (5.3%), pyrrole (8.1%), 3-methylindole (1.5%), decene (1.1%), decane (1.25%), undecene (1.4%), undecane (1.9%), dodecane (1.4%), tridecene (1.9%), tridecane (1.4%), tetradecene (1.2%), tetradecane (0.9%), pentadecene (1%), pentadecane (1.2%), heptadecene (1.1%), heptadecane (1.4%), 2-heptadecanone (4%), oleic acid (2.9%), 3-eicosyne (1.6%) and numerous unidentified components. Example 22 Salmon meat with calcium hydtoxide

[0188] A slurry of salmon meat (23.6 g) with Ca(OH), (10 g) was reacted at 275°C for 30 mins, then cooled and filtered to yield 24.1 g of residue. 2 g of this was pyrolysed to give 810 mg oil, which comprised: toluene (19.6%), ethyl benzene (3.3%), xylene (2.9%), nonene (1.7%), nonane (2.6%), decene (1.9%), decane (1.9%), undecene (2.1%), undecane (0.9%), dodecene (1.9%), dodecane (1.3%), tridecene (2.4%), tridecane (1.4%), tetradecene (2.7%), pentadecene (1.7%), pentadecane (1.6%), heptadecene (1.1%), 2-heptadecanone (3.1%), methyl oelate (4.8%) and numerous unidentified compounds.

Example 23 Olive pomace

[0189] A slurry of olive pomace (22.45 g) with Ca(OH)₂ (10 g) was reacted at 275°C for 30 mins, then cooled and filtered to yield 22.2 g of residue which, when pyrolysed, gave 2.11 g of oil, which comprised: toluene (12.3%), ethyl benzene (2%), xylene (2.9%), naphthalene (3.1%), nonene (1.1%), nonane (1.7%), decene (1%), decane (1%), undecene (1%), undecane (0.4%), dodecane (0.5%), tridecene (0.7%), tridecane (1.3%), tetradecene (1.6%), pentadecene (0.6%), pentadecane (0.5%), methyl 9-hexadecenoate (1.1%), methyl hexadecanoate (4%), methyl oleate (21%), oleic acid (5.1%) and numerous unidentified compounds.

INDUSTRIAL APPLICATION

[0190] The method of the invention may be used to produce:

(a) materials such as aromatic hydrocarbons, linear alkanes and alkenes, and lighdy oxygenated volatile hydrocarbons able to be used directly as additives to fuel,

(b) chemical products which. may act as feedstock for other chemicals,

(c) pyrazines that may be used direcdy as flavour enhancers, (d) polymethylated pyrazines that may be oxidized to make diacids suitable for biopolymers, particularly hydrophilic biopolymers.

(e) ethyl benzene, which would be a bioprecursor to styrene, or styrene itself, which permits a renewable sopurce of polystyrene, and related polymers such as an unsaturated polyester component, an ABS component, etc.

(f) lactams, which may be used as industrial solvents of high polarity.

[0191] The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention.

Claims

WHAT WE CLAIM IS:

1. A method for producing a fuel or fuel precursor from lipid-containing biomass comprising: heating an aqueous slurry comprising lipid containing biomass and water in a pressure vessel at a temperature of about 200°C to about 350°C in the presence of a metal base to produce a solid phase comprising one or more precipitated metal soaps and an aqueous phase, and separating the solid phase from the aqueous phase, and heating the solid phase to the decomposition temperature of the one or more metal soaps.

The method of claim 1 further comprising separating one or more organic chemical products from the aqueous phase.

The method of claim 1 further comprising heating the aqueous phase to temperatures of about 350°C to about 500°C, optionally in the presence of a catalyst.

The method of any one of claims 1 to 3 wherein the aqueous slurry is heated to about 240°C to about 300°C for the purpose of selectively preparing the pyrazines in the aqueous phase.

The method of any of one claims 1 to 4 wherein the solid phase is heated at about 300°C or more.

The method of any one of claims 1 to 4 wherein the solid phase is heated at about 400 to 900°C or more, or at about 400 to 600°C.

The method of any one of claims 1 to 6 wherein the aqueous solution following separation of the solid phase, either with or without extraction or separation of any additional organic component, is heated to near critical or supercritical temperatures, optionally in the presence of a catalyst to prepare further organic materials.

The method of any one of claims 1 to 6 wherein the aqueous solution following separation of the solid phase is steam distilled to separate pyrazines from lactams.

The method of any one of claims 1 to 8, wherein the aqueous phase or the mixture of the solid phase and the aqueous phase is subjected to a solvent extraction step to separate residual organic phase from the aqueous phase.

10. The method of any one of claims 1 to 8, wherein the aqueous phase or the mixture of the solid phase and the aqueous phase is subjected to a sequence of solvent/ aqueous extraction steps with sequential changes of pH to separate the classes of organic compounds.

11. The method of any one of claims 1 to 4, wherein the solids separated from the liquid are pyrolysed by heating at temperatures from 400°C to about 600°C for a period of about 1 minute to aboutlO hrs, preferably in the absence of oxygen, and the resultant liquids emitted are condensed and collected. ,

12. The method of any one of claims 1 to 4, wherein the solids separated from the liquid are treated hydrothermally at temperatures in excess of 300°C for a period of about 1 minute to aboutlO hrs, and on subsequent cooling, the organic liquids are separated or extracted from the aqueous solution.

13. The method of any one of claims 1 to 12 wherein components dissolved or dispersed in water are recovered by adsorbing them onto a solid, including but not limited to a clay, treated or otherwise, a zeolite, an ion-exchange resin, charcoal, aluminium oxide, etc, and recovering the components either by heating them, or through ion exchange.

14. The method of any one of claims 1 to 12 wherein organic components are extracted with solvents insoluble in water, including but not limited to methylene chloride, hydrocarbons, esters such as ethyl or amyl acetate, ethers, and the solvents are removed by distillation, or hydrocarbon mixtures prepared by a method of any one of claims 1 to 13.

15. The method of claims 11 or 12 wherein the pyrolysis product or hydrothermal product is distilled to separate hydrocarbons suitable for petrol from those suitable for diesel.

16. The method of claims 11 or 12 wherein the cations are either calcium or magnesium, and the final solid residue is used for agricultural or horticultural application.

17. The methods of any one of claims 1 to 16, wherein the pressure vessel is either batch or continuous, and may be stirred, fluid bed or fixed bed.

18. The method of claim 1 wherein the pyrolysis vessel may be batch or continuous, it may be ablative, fluid bed, stirred, or fixed bed.

19. The method of any one of claims 1 to 18, wherein the aqueous slurry is heated for about 1 minute to about 12 hours.

20. The method of any one of claims 1 to 18, wherein the aqueous slurry is heated for a time period of about 5 minutes to about 60 minutes.

21. The method of any one of claims 1 to 20, wherein the lipid containing biomass comprises about 2% to about 90% dry weight equivalent of the slurry.

22. The method of any one of claims 1 to 20, wherein the lipid containing biomass comprises about 10% to about 30% dry weight equivalent of the slurry.

23. The method of any one of claims 1 to 20, wherein the lipid containing biomass comprises about 5% to about 40% dry weight equivalent of the slurry.

24. The method of any one of claims 1 to 23 wherein the metal base is a material that reacts with acid to form a salt and materials that are only mildly acid or are neutral.

25. The method of any one of claims 1 to 24 wherein the metal base is an oxide or hydroxide.

26. The method of any one of claims 1 to 24 wherein the metal base is a Carbonate or a

sulphide.

27. The method of any one of claims 1 to 26 wherein the cation in the metal base is divalent, including but not restricted to magnesium, calcium, barium, strontium, zinc, cadmium, copper, nickel, cobalt, manganese, vanadyl, tin, lead and ferrous

28. The method of any one of claims 1 to 26 wherein the cation in the metal base is trivalent, including but not restricted to ferric, aluminium, chromic, scandium and rare earths.

29. The method of any one of claims 1 to 28 wherein the lipid containing biomass is algae or microalgae.

30. The method of any one of claims 1 to 28 wherein the lipid containing biomass is vegetable material either grown specifically for oil production or adventitious, including but not limited to plant oils such as olive, canola, jatropha, flax, soy, palm, coconut, or peanut oil, or wastes remaining after such oil pressing.

31. The method of any one of claims 1 to 28 wherein the lipid containing biomass is of animal origin, including meat, fish, and bird processing wastes.

32. The method of any one of claims 1 to 31 wherein the lipid containing biomass comprises waste lipid oils. The use of ethyl benzene or styrene obtained from the mixture produced according to the method of claim 1 for manufacturing polystyrene of biological origin.

The use of dialkylated or polyalkylated pyrazines obtained from the mixture produced according to the method of claim 1 for manufacturing by oxidation pyrazine dicarboxylic acids or pyrazine poly carboxylic acids or anhydrides for the precursors of condensation polymers of biological origin.