WO1994026844A2

WO1994026844A2 - Method and apparatus for microwave separation of hydrocarbons or water from emulsions

Info

Publication number: WO1994026844A2
Application number: PCT/US1994/005351
Authority: WO
Inventors: Rodney D. Jones; John G. Gilstrap; George M. Harris; Leonard J. Groves; Peter Robicheau
Original assignee: Thermal Wave International, Inc.
Priority date: 1993-05-11
Filing date: 1994-05-11
Publication date: 1994-11-24
Also published as: WO1994026844A3; AU6787694A

Abstract

Method and apparatus for substantially atmospheric separation of hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids. Microwave energy is applied to the emulsion or dispersion via a waveguide (3, 6) that is pressurized above atmospheric pressure. The microwave energy may be split, automatically tuned, and converted to a substantially circular phase. The method and apparatus are particularly adapted for treating oilfield sludge located in outdoor pits (100).

Description

DESCRIPTION

METHOD AND APPARATUS FOR MICROWAVE SEPARATION OF HYDROCARBONS OR WATER FROM EMULSIONS

OR DISPERSIONS OF WATER, HYDROCARBONS, AND/OR SOLIDS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to an apparatus and method for atmospheric separation of hydrocarbons or water from emulsions or dispersions of hydrocarbons, water, and/or solids by applying microwaves to the emulsions or dispersions. An embodiment of the invention is adapted to economically recover hydrocarbons from emulsions and dispersions in the form of oilfield sludge accumulated in open pits. This sludge is an environmental hazard produced from "tank bottoms" in the oil and gas production industry.

2. Description of the Prior Art

Microwave energy has been used to separate emulsions and dispersions of hydrocarbons and water. For instance, U.S. Patent

No. 4,582,629 to Wolf discusses separation of hydrocarbon and water emulsions and dispersions by the application of microwave radiation in the range of from 1 millimeter to 30 centimeters.

U.S. Patent No. 4,853,507 to Samardzija discusses an apparatus for de-emulsification of liquids using microwave energy as radiated into an applicator section of characteristic frequency dimensions consisting of a wave guide section that has a taper applicator element of low dielectric constant material separating the wave guide section into a radiation input void end and a larger volume liquid-filled output end.

U.S. Patent No. 4,810,375 to Hudgins et al. discusses a microwave emulsion treater with oily water recycle for a water load.

U.S. Patent No. 4,855,695 to Samardzija discusses an automated microwave tuning system for de-emulsification systems. U.S. Patent No. 4,067,683 to Klaila discusses a method and apparatus for controlling fluency of high viscosity hydrocarbon fluids.

U.S. Patent No. 4,620,593 to Haagensen discusses a oil recovery system and method which includes a slotted radiating unit that is lowered into a well casing of limited cross section, and wherein microwave energy is fed downwardly thereto via a transmission line also installed in the casing.

All of the above patents are hereby incorporated by reference.

None of the above art is believed to focus on treatment of hydrocarbon, water, and solid emulsions in open pits.

SUMMARY OF THE INVENTION

In a broad aspect, this invention relates to apparatus and processes for substantially atmospheric separation of hydro¬ carbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids. Although the embodiments described herein relate primarily to hydrocarbon separation, it is to be under- stood that water separations may also be achieved using the apparatus and processes of the invention.

One embodiment of the invention includes a microwave generator for generating microwave energy during use, and a waveguide coupled to direct microwave energy from the generator to a microwave disperser during use, the waveguide being adapted to be pressurized above atmospheric pressure during use. This embodiment is preferably adapted to separate hydrocarbons or water from the emulsion or dispersion at substantially atmospheric pressure during use. In another embodiment, the apparatus of the invention may include an automatic tuner for tuning microwave energy in the waveguide during use. This automatic tuner may be adapted to minimize microwave energy reflected towards the generator during use, and to maximize microwave energy dispersed from the disperser during use.

Preferably the apparatus of the invention may include a fluid-filled microwave energy sink coupled to the waveguide to receive microwave energy reflected towards the generator from the waveguide during use. This fluid filled sink may be coupled to the automatic tuner and a temperature sensor, thereby allowing control of the automatic tuner as a function of the temperature in the sink.

Alternately, the apparatus of the invention may include a sensor to tune microwave energy as a function of signals received from the microwave sensor during use.

In another embodiment the invention may be used to treat emulsions or dispersions in an open pit. A pumping or transfer system may then remove liquids formed in the pit as a result of the microwave treatment. The rate of liquid removal or the amount of microwave energy applied may vary as a function of the temperature of the liquid removed. The microwave energy may be split into several portions to more evenly disperse the energy, thereby providing for more efficient application, as well as reducing operating temperature (and increasing operating lives) of equipment used.

In one embodiment the microwave energy is converted to circular phase prior to application of microwave energy to the emulsion or dispersion. Circular phase is believe to provide a more even and efficient application of microwave energy to sludge.

In another embodiment, liquid transferred from a pit may be settled and further treated in a second microwave applicator. This applicator may also have a pressurizable waveguide, but may include a vessel for treating these liquids. The vessel may include a reflector for more efficient application of microwave energy in the vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an apparatus of the invention.

Figure 2 shows a microwave splitter, disperser, etc. in a pit^'.

Figure 3 shows a vessel connected to a microwave disperser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the invention is shown in Figure 1. The system or apparatus in Figure 1 is connected to treat sludge in a pit 100. This sludge may typically include emulsions or dispersions of hydrocarbons, water, and/or solids. Typically this sludge is accumulated near hydrocarbon production facilities. For instance, in the past common practice in the oil industry was to fill pits with bottom solids and water ("BS&W") separated from adjacent oil and gas production facilities. This "BS&W" often forms a sludge which includes emulsions and dispersions of hydrocarbons, water and/or solids.

Figure 1 depicts an apparatus for atmospheric separation of hydrocarbons and/or water from an emulsion or dispersion of hydrocarbons, water, and/or solids in an open pit. This apparatus includes a generator 1 for generating microwave energy during use. In a preferred embodiment the generator 1 produces about 60 kilowatts ("kw") at 915 Megahertz. Preferably generator 1 is placed in a housing or trailer 200. In a preferred embodiment, the entire apparatus is transferrable from location to location, and thus generator 1 is preferably placed in a movable trailer.

In Figure 1 microwave energy is transmitted from generator 1, through barrier 4, and into waveguide 6. Barrier 4 is preferably substantially permeable to microwave energy but substantially impermeable to liquids and gas. Barrier 4 is provided to help prevent backflow of contaminants such as solids, liquid, and gas into generator 1. If these contaminants are volatile, barrier 4 serves as a safety shield to prevent explo¬ sions and/or fires in or about generator 1. Barrier 4 also serves to prevent the transfer of noxious or poisonous materials into trailer or housing 200.

Barrier 4 may be placed between two flange connections as shown in Figure 1. In a preferred embodiment, barrier 4 is fabricated of industrial virgin teflon approximately 1/4 to 3/8 of an inch thick. The teflon has a dielectric constant of about 2.3 which tends to capacitively load the electric portion of the electromagnetic field distribution in waveguide 6. A counter¬ acting inductive load is preferably built into the barrier 4 frame so as to appear transparent to the high power microwave signals.

Waveguide 6 is preferably adapted to be pressurized to above atmospheric pressure with a gas during use. Preferably this gas is an inert and/or noncombustible gas such as nitrogen. Preferably the gas is substantially free of water. An apparatus that includes a pressurizable waveguide 6 for atmospheric pressure conditions is unexpectedly necessary and beneficial for several reasons. It is operable in outdoor conditions, and is safer.

A pressurizable waveguide is operable in outdoor conditions because the gas on the inside of the waveguide 6 tends to main- tain the interior of the waveguide 6 in a substantially dry and clean condition. If the waveguide 6 is not pressurized, rain, condensation, and dirt tend to accumulate in the interior of the waveguide 6. As a result, microwave energy in the waveguide 6 becomes distorted by the dirt, and improperly directed by the moisture.

Filling the waveguide 6 with a noncombustible gas such as nitrogen helps make the waveguide safer by preventing an explo¬ sion or fire that might result if hydrocarbons (which are typically separated from the emulsion) migrated into the micro¬ wave-filled waveguide. This safety advantage is important in many applications since the microwave energy often significantly raises the temperature of the hydrocarbons being treated. For instance, the apparatus shown in Figure 1 has been found to raise hydrocarbon temperatures to about the boiling point of water. As a result, some of the hydrocarbons in pit 100 vaporize and mix with the surrounding air. If this mixture were to migrate into an unpressurized waveguide, then microwave arcing in the wave¬ guide could easily cause the hydrocarbons to explode. Pressuriz- ing the waveguide with noncombustible nitrogen provides two safety features: (1) it prevents hydrocarbons from entering the waveguide 6, and (2) it tends to lower the explosiveness of hydrocarbon-air mixtures by diluting the oxygen content of these mixtures.

The apparatus shown in Figure 1 is preferably adapted to separate hydrocarbons and/or water from an emulsion or dispersion by applying microwave energy towards or in the emulsion or dispersion at atmospheric pressure. As a result, although the waveguide 6 is pressurized, it need not be built to withstand higher pressures typically required for many applications (e.g. , downhole applications) . Thus substantial savings can be realized on the construction of the waveguide as compared to waveguides used in downhole applications (which must typically be able to withstand hundreds of pounds of pressure -- see, e.g., U.S. Patent No. 4,620,593 to Haagensen) . Even so, a waveguide 6 that is adapted to even maintain some pressure generally requires somewhat thicker and airtight walls than if it were not pressurizable. Thus waveguide 6 tends to be generally more expensive, heavy, and difficult to transport and piece together than ordinary waveguides not built for pressure conditions, but much less expensive, heavy, and difficult to transport than high pressure downhole waveguides.

Thus, in a preferred embodiment waveguide 6 is built for pressure conditions, but is still relatively light and inexpen- sive compared to downhole waveguides. Preferably waveguide 6 is adapted to be pressurized to pressures less than about 10 psig pressure, more preferably less than about 5 psig pressure, and more preferably still less than about 2 psig pressure.

Waveguide 6 may have a square, rectangular, or circular cross-section. In a preferred embodiment the waveguide 6 is made of rectangular aluminum.

In Figure 1 waveguide 6 may be connected to a pair of E- bends 8, which are 90 degree turns in the waveguide. The E-bends

8 are angled so that they reflect microwave energy from a horizontal path to a vertical path, or vice versa.

From E-bends 8 microwave energy may then be preferably guided through circulator 10, a 60 degree H-bend 14, and automatic tuner 16. The automatic tuner 16 may be manually controlled, or controlled via computer 66. Automatic tuner 16 is for tuning microwaves in the waveguide to vary the microwave energy dispersed during use. More specifically, automatic tuner 16 may be adapted to minimize microwave energy reflected towards the generator 1 during use, and to maximize microwave energy dispersed during use. In this manner more efficient application of microwaves is achieved.

One automatic tuner that may operate adequately is the Model B-20273-301 high power WR-975 Real Time Autotuner. This equip¬ ment is sold by RF Technologies Corporation in Lewiston, Maine. The circulator 10 may be connected to a fluid-filled micro¬ wave energy sink or "water load" 12 which is connected to absorb or receive microwaves reflected towards the generator 1. The energy sink 12 may be coupled to a temperature sensor 101 which is connected to send signals to the automatic tuner 16 and/or the computer 66. The signals from the temperature sensor 101 will vary depending on the temperature of the fluid in the energy sink 12, which is in turn dependent on the amount of microwave energy reflected to energy sink 12. The automatic tuner 16 may then be adapted to tune the microwave energy as a function of the temperature of the fluid in the energy sink. This response may be direct, or through control of computer 66.

Alternately, the apparatus in Figure 1 may include a micro- wave energy sensor 103 which measures the amount of microwave energy reflected in waveguide 6. The energy sensor 103 may be connected to the automatic tuner 16 so that the automatic tuner 16 varies (tunes) the microwave energy as a function of informa¬ tion received from the microwave energy sensor 103 during use.

Figure 1 shows automatic tuner 16 with movable pistons 18. These movable pistons move tuning barriers between different locations to tune the microwave energy.

From automatic tuner 16 the microwave energy may be directed through waveguide 6 to a wave splitter or "Magic Tee" 22. See Figures 1 and 2. As shown in Figure 1, the waveguide 6 may extend over the pit 100 so that microwave energy may be directed downwardly towards the sludge in pit 100. A catwalk 31 may provide access to the wave splitter 22 and other equipment that extend over the pit 100.

A second barrier 20 may preferably be placed between wave¬ guide 6 and wave splitter 22. This barrier 20 serves substan- tially the same purpose as barrier 4. Wave splitter 22 is connected to split the microwave energy transmitted through the waveguide 6 during use. Preferably the microwave energy is split into substantially equal portions. Splitting the microwave energy is beneficial because it may permit a broader, more even, and more efficient application of the microwave energy to the emulsion or dispersion, especially when such emulsion or dispersion is in the form of sludge in a pit. For instance, it has been discovered that generally more separation can be achieved per kw of microwave energy if two 30 kw microwave signals are applied to two separate areas in a sludge pit, instead of one 60 kw microwave signal applied to only one area of the pit. It is believed that one 60 kw signal is less efficient since it tends to excessively heat the sludge in a small location, thereby causing more ambient energy losses, and higher equipment failures rates.

An additional benefit of the wave splitter 22 is that multiple lower energy dispersers (e.g., dispersing about 30 kw) tend to wear slower than a single higher energy disperser (e.g., dispersing about 60 kw) , mainly because the lower energy dispersers tend to heat less during use (hydrocarbons and water in the sludge separate and heat during use - some of that heat, which is a function of the amount of microwave energy applied, tends to be transferred to the proximate dispersers) .

In addition to more efficient dispersion, wave splitter 22 also permits more economical application of microwave energy (measured in dollars per kw of microwave energy applied) . For example, less equipment and operating expenses (on a per kw basis) are required to generate a 60 kw signal, split it into two 30 kw signals, and apply it, as compared to independently generating and applying two 30 kw signals. These lower expenses are achieved because two 30 kw generators are more expensive to purchase, maintain, and operate than one 60 kw generator (on a per kw basis) . Furthermore, a one generator system only requires that one energy sink, automatic tuner, etc. be purchased, operated, and maintained, versus two of everything for a two generator system.

In short, wave splitter 22 permits the apparatus to overcome inefficiencies, but retain some of the benefits, of single generator systems. It has been found that preferred results may be obtained for sludge pits if wave splitters are employed such that each portion of microwave energy is less than about 50 kw, and more preferably 20-40 kw, and more preferably still 25-30 kw. In a preferred embodiment the wave splitter 22 was made by RF Technologies (Lewiston, Maine) .

Wave splitter 22 is preferably constructed to preferentially reflect and/or absorb microwave energy sent back from the dispersers 30. In a preferred embodiment, wave splitter 22 reflects as much energy as possible back to the dispersers 30, and is coupled to a H-plane energy sink 24 which absorbs energy that is not reflected back to the dispersers 30. H-plane energy sink 24 preferably extends upwardly from wave splitter 22. The H-plane energy sink 24 is preferably a liquid resistor type high power waveguide termination. Water containing ions is pumped through virgin teflon-contained water columns placed in a WR-975 waveguide section. Microwave signals incident on the termination are then dissipated in the water and converted to heat. The heated water is then pumped out of the sink and cooled in a conventional heat exchanger cooler.

From splitter 22, microwave energy may preferably travel through mode converters 26 which convert the microwave energy from a substantially rectangular waveform (i.e., rectangular "phase" or polarization) to a substantially circular waveform, or vice versa. In a preferred embodiment the microwave energy is generated, tuned, and transmitted in a substantially rectangular waveguide 6. This energy is then converted to a substantially circular form just prior to dispersal to the sludge. It is believed that substantially circular microwave energy provides a more even, and thus more efficient, distribu- • tion of microwave energy when applied to emulsions or dispersions.

From mode converters 26 the microwave energy may pass through flanges 29 and circular waveguide 28, which are in turn connected to dispersers 30. Dispersers 30 disperse microwave energy to the emulsion or dispersion during use. In Figure 2 the emulsions or dispersions are in a pit 100. These dispersers are preferably located in the emulsion or dispersion, although they may be also located proximate (e.g. above) the dispersion or emulsion. The dispersers 30 are preferably substantially permeable to microwave energy, and also substantially impermeable to fluids. Although two dispersers 30 are shown in Figure 2, it is to be understood that only one disperser may be used in certain applications, and that more than two dispersers may be used in other applications. Having more than one disperser, however, is preferred for reasons discussed above.

Preferably the wave splitter 22, the mode converters 26, the circular waveguide 28, and the dispersers 30 are filled with gas to a higher pressure than the waveguide 6 and associated equip¬ ment (e.g., automatic tuner 16, etc.). This higher pressure provides an additional safety factor to prevent hydrocarbons from migrating into waveguide 6. The higher pressure is usually possible without substantially more expensive equipment since off-the-shelf wave splitters 22, mode converters 26, circular waveguides 28, and dispersers 30 are usually built strong enough to withstand somewhat higher pressures. Preferably the higher pressure is less than about 20 psig, more preferably between 1 and 10 psig, more preferably still between 2 and 15 psig. In one embodiment the higher gas pressure was 10 psig.

Preferably dispersers 30 are made of a material that is substantially stable in the presence of water and hydrocarbons at pressure differentials of about 20 psi at 1000°F. It is also preferable that the dispersers 30 have a substantially non-stick, low friction surface comparable to that of teflon. The dispersers 30 shown in the figures are substantially cone-shaped, however it is to be understood that other shapes of dispersers may be used in some applications. The dispersers 30 may be solid or hollow. In a preferred embodiment the dispersers 30 were made of solid cones made of Dow Corning Pyroceram 9090.

The microwave energy may be dispersed from the dispersers 30 to the emulsion or dispersion during use. After being treated with this energy, the emulsion or dispersion tends to separate into liquid and solid layers, with the solids falling to the bottom and the liquids being further roughly separated into water and hydrocarbon phases. The microwave energy tends to cause the solids and liquids to become hot.

As shown in Figures 1 and 2, liquids may be transferred or pumped from the pit through conduit 32. At least a portion of conduit 32 is preferably substantially permeable to microwave energy. In a preferred embodiment a portion of conduit 32 may be made of teflon. At some point conduit 32 may be connected to conduit 35, which is preferably made of steel.

Liquids from pit 100 may be transferred through conduit 32, through solid separator or strainer 36 (see Figure 1) , and then through pump 38. Conduit 32 is preferably located such that its pit end is at or higher than the level of the dispersers 30. In this manner liquids sucked into conduit 32 tend to have a higher percentage of hydrocarbons (versus the more dense solids and water) than if conduit 32 was lower than the dispersers 30.

Pump 38 is preferably a progressive cavity pump. From pump

38 the liquids may be transferred through flow sensor 39 and into tank 61.

Preferably liquid temperatures are monitored at the base of each disperser 30, in conduit 32 and/or 35, and after pump 38.

The temperature may be monitored by, e.g., "type e" thermo- couplings, and transmitted to control computer 66. The flowrate through pump 38 may be varied as a function of the temperature of liquids in conduits 32 and/or 35, either directly or under the control of computer 66.

Since liquid temperature is dependent on the degree of microwave energy applied, varying the flowrate of liquids pumped from the pit as a function of liquid temperature in effect provides a rough method of varying flowrate as a function of the degree that the liquids have been treated. For instance, as the rate that liquids are removed from the pit 100 increases, the average temperature of these liquids correspondingly decreases because less microwave energy will have been applied to these liquids (assuming everything else remains substantially constant) . Since less microwave energy has been applied (per unit volume of liquid) , the liquids are less likely to have been fully treated to reduce the dispersion or emulsion.

The liquids from pump 38 are preferably pumped through a "down comer" into a settling tank 61. From settling tank 61 the lighter liquids are passed through conduit 42 to tank 44 where they are sold and/or recycled for further treatment.

If the first treatment is adequate, hydrocarbons in tank 44 may be sold through conduit 65 without further treatment. Often, however, further treatment is necessary to provide hydrocarbons in salable form.

To provide additional treatment, the bottoms from tank 44 may be recycled via conduit 63 and pump 62 into an applicator or vessel 60 (see Figures 1 and 3) . Preferably the bottoms in conduit 63 enter the top portion of applicator 60. In a preferred embodiment, conduit 63 may be split into four portions which enter the top portion of applicator 60 at 90 degree angles. In this manner liquids tend to fall more evenly over and around disperser 58. Once inside applicator 60, the bottoms from conduit 63 pass over or proximate to a disperser 58 which may in some applica¬ tions be substantially similar to dispersers 30. A level controller 102 may direct the release of liquid from the applicator 60 via conduit 108. Gas may be released from the applicator 60 via conduit 106 and pressure control valve 104.

Liquid flows through the applicator 60 until it reaches the underside of reflector 114. The liquid then preferably follows the path shown by arrows 110 in Figure 3 and emerges from the vessel via conduit 108. In this manner solids tend to settle from the liquids prior to these liquids following the path shown by arrows 110. The solids pass from the applicator 60 via conduits 114 or 118. Section 125 of the applicator 60 may preferably include an auger 126 to prevent and/or dislodge clogged solids.

Manhole 112 provides access to applicator 60 for cleaning and maintenance. Supports 152 provide support for applicator 60.

Flowrate through applicator 60 may be controlled as a function of the temperature of the fluid within applicator 60. Temperature sensors 120 and/or 122 may provide a signal to pump 62, either directly or under the control of computer 66, which directs pump 62 to increase flowrate as the temperature decreases below a predetermined level, or vice versa. As with pit 100, temperature in applicator 60 provides a rough estimate of the degree of treatment.

As shown in Figures 1 and 3, the treatment process in applicator 60 is powered by microwave generator 2 which may be substantially similar to generator 1 described above. Microwave energy may pass through pressure barrier or window 52, wave guide 3, E-bends 5, circulator 54, automatic tuner 132, barrier 134, mode converter 56, disperser 58, and into the liquids in applicator 60. All of this equipment may be substantially the same as the equivalent equipment described above, both in structure and in how it is controlled. Microwave energy may be reflected back and forth between disperser 58 and reflector 114, reflector 114 being constructed to enhance such reflection. The liquid level in applicator 60 is preferably maintained above disperser 58. Otherwise, disperser 58 tends to become too hot and fails. If reflected, microwave energy passes twice through the liquids, thus enhancing the efficiency of the application process.

Preferably the liquids in applicator 60 are exposed to about 20-60 kw of microwave energy. Liquids from applicator 60 may then flow via line 150 into settling tank 61 through downcomer 64 for further settling time.

Both microwave treating systems may be controlled by computer 66 . The computer 66 may monitor reflected microwave energy in the waveguides, and provide control of the automatic tuners to minimize it. The computer 66 may monitor and control flow rates of both treatment systems by communicating with, e.g., flow meter 39, pump 38, and pump 62. The computer 66 may also monitors liquid temperatures in the pit 100, coming out of pit 100, prior to entering applicator 60, after applicator 60, and in tanks 44 and 61. Computers which are programmable to control such process systems are available in the art.

EXPERIMENT

The system and process shown in Figures 1-3 were tested at a location proximate to a Navajo Company refinery in Artesia, New Mexico. Microwave energy was applied at steady state to a 10,000 barrel tank sludge pit containing BS&W sludge (i.e., an emulsion or dispersion of hydrocarbon, water, and solids) from oil production. This sludge was so viscous and full of solids that the pit had a solid crust which could be safely walked upon by a two hundred pound man at ambient temperatures of 60 °F. The emulsion in this pit was tested to be 20% hydrocarbon, 15% water, and 65% solids. Sixty kw (at 915 Megahertz) of microwave energy was applied to the pit through a system as shown in Figures 1-2. The wave splitter 22 divided the sixty kw of microwave energy into two portions of roughly thirty kw apiece. These portions were dispersed towards the pit 100 through dispersers 30, as shown in Figure 2, which were fully immersed into the sludge of the pit 100.

After one hour, a circle of black boiling liquid formed in the crust surrounding the dispersers 30. This circle was about 15-20 feet in diameter. The boiling liquid included hydro¬ carbons, water, and solids. It was pumped out of pit 100 at a rate of about 20 gpm at temperatures ranging from 180 to 205°F.

The liquid pumped from the pit 100 was tested and found to contain about 5 percent solids, 7.5 percent water, 67.5 percent hydrocarbons, and 20 percent of an emulsion of hydrocarbons, water, and solids. This liquid was pumped into a settling tank

61, as shown in Figure 1.

After eight hours of pumping liquid out of pit 100 at 20 gpm, settling tank 61 began to fill to a level wherein hydro¬ carbons could be skimmed into tank 44. Water from the bottom of tank 61 (and from the other equipment in the system) was periodically pumped to standard oilfield water treatment facilities. The liquid in tank 44 was tested and found to con¬ tain 16.3 percent solids, no measurable water, and 83.7 percent hydrocarbons.

No further treatment occurred until tank 44 accumulated 50 barrels of liquid. At this point, pump 62 transferred liquid from tank 44 via conduit 63 into applicator 60. The flow rate through applicator 60 was set at a rate of 30 gpm. Microwave energy was applied at a power setting of 60 kw. Liquid entered the applicator 60 at 160°F and left applicator 60 via line 108 at 215°F. Solids were periodically drawn from applicator 60 via lines 114 and 118. These solids were disposed in a temporary pit, and later removed to a permanent storage location. After five hours of recirculation between tank 61, tank 44, and applicator 60, liquid in tank 61 was at a temperature of 202°F, and liquid in tank 44 was at 195°F. Recirculation was found to be beneficial because repeated microwave application and relatively high liquid temperatures in tanks 44 and 61 helped to "break" any remaining emulsions or dispersions. At this point the liquid in tank 44 was tested. It was found to contain no measurable water, 0.5 percent solids, and 99.5 percent oil with an API gravity of 27.1.

As illustrated above, the apparatus and method of the inven¬ tion may provide an economical and efficient way of treating emulsions or dispersions such as oilfield sludge. First, the apparatus and method of the invention provided a system to transform a highly dense solid into a pumpable liquid. Second, the liquid was processed to substantially separate solids, water, and hydrocarbons. Third, in addition to producing salable crude oil, the apparatus and method of the invention provided a way to remove environmentally hazardous materials that may be stored in earthen pits. It is anticipated that this invention may be used to treat a wide variety of hazardous materials that are presently stored as such. Fourth, the apparatus and method of the invention is economical because it is transferrable from location to location, and is adapted to operate in outdoor conditions.

Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carry¬ ing out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein or in the steps or in the sequence of steps of the methods described herein without departing from the spirit and scope of the invention as described in the following claims.

Claims

CLAIMSt

1. An apparatus for substantially atmospheric separation of hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids during use, comprising:

a microwave generator for generating microwave energy during use;

a waveguide coupled to direct microwave energy from the generator to a microwave disperser during use, the waveguide being adapted to be pressurized above atmospheric pressure during use; and

wherein the apparatus is adapted to separate hydrocarbons or water from the emulsion or dispersion at substantially atmospheric pressure during use.

2. The apparatus of claim 1, further comprising a substantially microwave permeable and fluid impermeable barrier connected between the generator and the waveguide.

3. The apparatus of claim 1, further comprising a substantially microwave permeable and fluid impermeable barrier connected between the waveguide and the disperser.

4. The apparatus of claim 1, further comprising an automatic tuner for tuning microwave energy in the waveguide during use.

5. The apparatus of claim 4 wherein the automatic tuner is adapted to minimize microwave energy reflected towards the generator during use, and to maximize microwave energy dispersed from the disperser during use.

6. The apparatus of claim 1, further comprising a fluid-filled microwave energy sink coupled to the waveguide to receive microwave energy reflected towards the generator from the waveguide during use.

7. The apparatus of claim 1, further comprising a fluid-filled microwave energy sink coupled to the waveguide to receive microwave energy reflected towards the generator from the waveguide during use, an automatic tuner coupled to tune microwave energy in the waveguide during use, and a temperature sensor coupled to the microwave energy sink and the automatic tuner such that the automatic tuner is adapted to tune microwave energy as a function of the temperature of the fluid in the sink during use.

8. The apparatus of claim 1, further comprising a fluid-filled microwave energy sink coupled to the waveguide to receive microwave energy reflected towards the generator from the waveguide during use, an automatic tuner coupled to tune microwave energy in the waveguide during use, and a microwave sensor coupled to the microwave energy sink and the automatic tuner such that the automatic tuner is adapted to tune microwave energy as a function of signals received from the microwave sensor during use.

9. The apparatus of claim 1 wherein the apparatus is adapted to treat emulsions or dispersions in an open pit during use.

10. The apparatus of claim 9 wherein the waveguide is extended over the pit during use.

11. The apparatus of claim 9 wherein the apparatus is adapted such that the microwave disperser is immersed in the pit during use.

12. The apparatus of claim 9, further comprising a transfer system adapted to transfer liquid from the pit, the transfer system being connected to a conduit having a first end connected to the transfer system and a second end inserted into the pit during use, the second end of the conduit being located proximate the microwave disperser.

13. The apparatus of claim 12, further comprising a temperature sensor for measuring the temperature of the liquid being transferred during use, the temperature sensor being coupled to the transfer system, and the transfer system being adapted to vary the liquid transfer rate as a function of the temperature of the liquid being transferred from the pit during use.

14. The apparatus of claim 12, further comprising a temperature sensor for measuring the temperature of the liquid being transferred during use, the temperature sensor being coupled to the generator, and the generator being adapted to vary the level of microwave energy directed to the waveguide as a function of the temperature of the liquid being transferred from the pit during use.

15. The apparatus of claim 12 wherein the second end of the conduit is coupled so that it is at the same level or higher than the microwave disperser during use.

16. The apparatus of claim 1, further comprising a wave splitter, the wave splitter being coupled to split the microwave energy transmitted through the waveguide into more than one portion during use, the waveguide being adapted such that the portions are transmitted during use to more than one microwave disperser.

17. The apparatus of claim 9, further comprising a wave splitter, the wave splitter being coupled to split the microwave energy transmitted through the waveguide into more than one portion during use, the waveguide being adapted such that the portions are transmitted during use to more than one microwave disperser placed proximate or in the pit.

18. The apparatus of claim 17 wherein each portion of microwave energy is equal to or less than about 50,000 watts.

19. The apparatus of claim 1, further comprising a mode converter to convert rectangular phase microwave energy to circular phase microwave energy prior to application of microwave energy to the emulsion or dispersion.

20. The apparatus of claim 12, further comprising an applicator coupled to the transfer system, the applicator being adapted to apply microwave energy to liquid transferred from the pit during use.

21. The apparatus of claim 20 wherein the applicator comprises a applicator disperser coupled to an applicator waveguide, the applicator waveguide being coupled to direct microwave energy to the applicator disperser during use, the applicator waveguide being adapted to be pressurized above atmospheric pressure during use.

22. The apparatus of claim 21, wherein the applicator comprises a reflector connected in relationship to the applicator disperser such that the applicator is adapted to reflect microwave energy

^■ in a space between the applicator disperser and the reflector during use, the space being at least partially filled with the emulsion or dispersion during use such that the applicator disperser is substantially immersed in the emulsion or dispersion during use.

23. The apparatus of claim 21, further comprising an applicator automatic tuner for tuning microwave energy in the applicator waveguide during use.

24. The apparatus of claim 23 wherein the applicator automatic tuner is adapted to minimize microwave energy reflected in the applicator waveguide during use, and to maximize microwave energy dispersed from the applicator disperser during use.

25. The apparatus of claim 21, further comprising a fluid-filled microwave energy sink coupled to the applicator waveguide to receive microwave energy reflected in the applicator waveguide during use.

26. The apparatus of claim 21, further comprising an applicator fluid-filled microwave energy sink coupled to the applicator waveguide to receive microwave energy reflected in the applicator waveguide during use, an applicator automatic tuner coupled to tune microwave energy in the applicator waveguide during use, and a temperature sensor coupled to the applicator microwave energy sink and the applicator automatic tuner such that the applicator automatic tuner is adapted to tune microwave energy as a function of the temperature of the fluid in the applicator sink during use.

27. The apparatus of claim 20, further comprising a separator adapted to separate solids from liquids, the separator connected between the transfer system and the applicator.

28. The apparatus of claim 20, further comprising a temperature sensor connected to measure the temperature of the liquid in the applicator, the temperature sensor being coupled to the transfer system such that the transfer system is adapted to vary the liquid transfer rate during use as a function of the temperature of the liquid in the applicator.

29. The apparatus of claim 22 wherein the applicator includes a top portion and a bottom portion, and wherein the applicator disperser is coupled to apply microwave energy downwardly from a top portion of the applicator, and wherein the applicator further comprises a reflector connected to reflect microwave energy upwardly from a bottom portion of the applicator.

30. A vessel for application of microwave energy to separate hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids within the vessel during use, comprising: a microwave disperser connected to disperse microwave energy from a waveguide that is adapted to be pressurized above atmospheric pressure to the emulsion or dispersion during use, the disperser being substantially permeable to microwave energy; and

a reflector connected in relationship to the disperser so that microwave energy is reflected in a space between the disperser and the reflector during use, the space being at least partially filled with the emulsion or dispersion during use such that the disperser is substantially immersed in the emulsions or dispersion during use.

31. The vessel of claim 30 wherein the vessel includes a top portion and a bottom portion, the disperser being connected to apply microwave energy in a downwardly direction from the top portion during use, and the reflector connected to reflect microwave energy upwardly from the bottom portion during use.

32. The vessel of claim 31, further comprising a liquid-gas controller coupled to maintain a liquid-gas interface in the vessel which is above the reflector.

33. A process for substantially atmospheric separation of hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids, comprising the steps of:

directing microwave energy from a microwave generator to a disperser through a waveguide that is pressurized above atmospheric pressure with a gas; and

dispersing microwave energy to the emulsion or dispersion at or near atmospheric pressure.

34. The process of claim 33, further comprising the step of automatically tuning microwaves in the waveguide to vary the microwave energy dispersed from the disperser during use.

35. The process of claim 33, further comprising the step of automatically tuning microwaves in the waveguide to minimize microwave energy reflected towards the generator during use, and to maximize microwave energy dispersed from the disperser during use.

36. The process of claim 34, further comprising the step of receiving microwaves reflected towards the generator in a fluid- filled microwave energy sink.

37. The process of claim 36, further comprising the step of automatically tuning microwaves in the waveguide as function of the temperature of the fluid in the fluid-filled microwave energy sink.

38. The process of claim 33 wherein the microwave energy is dispersed towards emulsions or dispersions in an open pit.

39. The process of claim 38, further comprising the step of extending the waveguide over the pit prior to or while dispersing the microwave energy towards the emulsions or dispersions in the pit.

40. The process of claim 38, further comprising the step of immersing the microwave disperser in the pit prior to or while dispersing the microwave energy towards the emulsions or dispersions in the pit.

41. The process of claim 38, further comprising the step of transferring liquid that is proximate the microwave disperser from the pit.

42. The process of claim 38, further comprising the step of transferring liquid from the pit as a function of a temperature of liquid proximate the microwave disperser.

43. The process of claim 41, further comprising the step of varying the level of microwave energy dispersed as a function of the temperature of the liquid transferred from the pit.

44. The process of claim 41 wherein liquid that is at the same or a higher level than the microwave disperser is transferred.

45. The process of claim 33, further comprising the step of splitting the microwave energy transmitted through the waveguide into more than one portions, the portions then being transmitted to more than one microwave disperser placed proximate or in the pit.

46. The process of claim 45 wherein each portion of microwave energy is equal to or less than 50,000 watts.

47. The process of claim 33, further comprising the step of converting rectangular phase microwave energy to circular phase microwave energy prior to application of^' microwave energy to the emulsion or dispersion.

48. A process of applying microwave energy to separate hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids, comprising the steps of:

directing microwave energy from a microwave generator to a disperser;

reflecting microwave energy in a space between the disperser and a reflector during use, the space being located so that it is at least partially filled with the emulsion or dispersion during use.

49. The process of claim 48 wherein the microwave energy is dispersed from a high to a low portion in an upright vessel, and reflected from a low to a high portion in the vessel.

50. The process of claim 49, further comprising the step of maintaining a liquid level in the vessel higher than the disperser.

51. A process for separating hydrocarbons or water from an emulsion or dispersion of hydrocarbons, water, and/or solids, comprising the steps of:

directing microwave energy to a microwave disperser through a waveguide that is pressurized above atmospheric pressure; and

dispersing microwave energy at or near atmospheric pressure from the disperser towards an emulsion or dispersion in a first applicator;

transferring liquid from the first applicator to a second applicator; and

directing microwave energy towards the liquid in the second applicator.

52. The process of claim 51, further comprising the step of separating water from the liquid prior to the liquid being transferred to the second applicator.

53. The process of claim 51, further comprising the step of separating solids from the liquid prior to the liquid being transferred to the second applicator.

54. The process of claim 51, further comprising the step of varying the amount of liquid transferred from the first applicator as a function of the temperature of the liquid in the first applicator.

55. The process of claim 51, further comprising the step of reflecting microwave energy in a space between the disperser and a reflector, the space being located so that it is at least partially filled with the emulsion or dispersion.

56. The process of claim 55 wherein the microwave energy is dispersed from a high portion to a low portion in the first or second applicator, and wherein microwave energy is reflected from a low portion to a high portion in the first or second applicator.

57. The process of claim 56, further comprising the step of maintaining a liquid level in the first or second applicator which is above the reflector.

58. The process of claim 51 wherein the microwave energy that is directed towards the liquid in the second applicator is directed through a waveguide that is pressurized above atmospheric pressure.

59. A hydrocarbon which has been separated from an emulsion or dispersion of hydrocarbons, water, and/or solids according to the process of claim 33.

60. A hydrocarbon which has been separated from an emulsion or dispersion of hydrocarbons, water, and/or solids according to the process of claim 48.

61. A hydrocarbon which has been separated from an emulsion or dispersion of hydrocarbons, water, and/or solids according to the process of claim 51.