RU2593995C1 - Method for off-grade fuel purification from asphaltenes and sulphur compounds and device for its implementation - Google Patents

Abstract

FIELD: fuel.

SUBSTANCE: invention relates to off-grade fuel purification from asphaltenes and sulphur compounds by mixing initial fuel fraction with extraction agent in the form of concentrated sulphuric acid followed by separation of the formed refined fraction by its treatment with neutralizing agent and water. Method distinctive aspect is that the initial fuel fraction is subjected to ozone oxidation prior to mixing, and fuel purification is single-flow in one cycle, where the extraction agent is used once in every cycle, and neutralising reagent is calcined soda, after treatment with water refined fraction is subjected to filtration and dehydration. Invention also relates to the device.

EFFECT: present invention provides a simple and efficient method and device for purification of dark, off-grade diesel and furnace fuel from undesirable impurities in one cycle of processing of initial fuel fraction and enables to obtain one whole flow of purified fuel, as well as to reduce the amount of used extraction agent - sulphuric acid, and to reduce the amount of hard-to-utilize residue (acid tar) formed upon extraction.

2 cl, 2 dwg

Description

This group of inventions relates to the field of oil refining and is intended for the purification of fuels from asphaltenes and sulfur compounds, in particular for the purification of high sulfur dark, substandard diesel and heating oils, and can be used in the oil refining industry.

The claimed group of inventions includes a method for cleaning substandard fuel from asphaltenes and sulfur compounds and a device for its implementation.

Substandard, contaminated with undesirable impurities diesel fuel and middle oil distillates, called dark furnace fuel, in large quantities contain unsaturated gum-forming hydrocarbons and other low-boiling coloring aromatic compounds. These unwanted contaminants lead to darkening of the fuel and, as a consequence, to the loss of its presentation.

The traditional industrial method of cleaning fuel from impurities is high-temperature hydrotreating with hydrogen-containing gas in the presence of platinum catalysts, which allows almost completely to remove sulfides, disulfides and mercaptans from liquid hydrocarbons (for example, SA Akhmetov “Technology for the deep processing of oil and gas”, Ufa: Gilem , 2002 .-- 672 p.).

However, since diesel fractions mainly contain thiophenes and benzo- and dibenzothiophenes, which are most difficult to remove during hydrotreating, the methods for catalytic hydrotreating of diesel fuel are not efficient enough. In addition, catalytic purification methods are quite difficult to implement in mini-refineries due to the high cost of the materials used (catalysts).

For the desulfurization of various types of motor fuels, including diesel fractions, the technology of extraction of sulfur-containing compounds from fuel into an ionic liquid is widely used. The process of cleaning motor fuels includes extraction of sulfur-containing compounds from fuel into an ionic liquid, partial oxidation of extracted sulfur-containing compounds by the action of a catalyst in an alcohol-alkaline solution or in an acidic aqueous solution, separation of the hydrocarbon fraction, and regeneration of the ionic liquid.

In this case, an ionic liquid is used, consisting of a cation selected from the group of alkylimidazolium, alkylpyridinium, polyalkylammonium, alkylpiperidinium, and an anion selected from the group of tetrafluoroborate, hexafluorophosphate, trifluoromethyl sulfonate (triflate), bis (trifluoromethyl sulfonyl acetate, nitrate, nitrate, nitrate. The catalyst contains one metal and / or metal oxide of the highest oxidation state, and the metal is selected from the group of transition metals, including molybdenum, vanadium, tungsten, manganese, chromium [for example, RU 2541315 C1, priority 10/18/2013].

The disadvantages of the methods for desulfurization of ionic liquids are high energy costs and inefficient electrolysis regeneration of ionic liquids associated with a constant change in the process parameters (current density, voltage and pH).

There is a method of treating motor fuel with an ozone-air mixture in order to improve their quality, according to which the ozone-air mixture is introduced into the fuel and then mixed, then the resulting mixture is moved through the mixing chamber, creating additional turbulent flows by passing current along part of the volume of the mixture flow. At the same time, ozone is used as a fuel oxidizer, which allows to improve the fractional composition of different types of fuels, including crude oil (increasing the number of lighter fractions without significantly losing the total mass of fuel), reduces the number of harmful sulfur-containing compounds and increases the octane number of fuel [RU 2158748 C1, Priority 10/20/1999].

The disadvantage of this method is the high foaming and the need for multiple processing of the fuel with an ozone-air mixture. Passing the electric current through the mixing chamber creates the danger of an explosion when deviations from the specified parameters.

The closest analogue of the proposed method of purification of fuel is a method for producing commercial diesel fuel from sour diesel fractions, based on the extraction of sulfur compounds from the fuel. A method of producing commercial diesel fuel from sour diesel fractions involves dividing the main stream of fuel fractions into three streams, followed by purification of each of them with an appropriate extractant and withdrawing the purified fraction from each of them to a neutralization unit to obtain commercial fuel from it. In this case, high-sulfur diesel fractions are used as fuel fractions, concentrated sulfuric acid is used as the extractant for the first stream, the extract phase from the first purification stream is used as the extractant, and the extract phase from the second purification stream is used for the third stream, moreover the extract phase from the third stream is washed with industrial water [RU 2514916 C1, priority 28.12.2012].

A disadvantage of the closest analogue is the low quality of diesel fuel purification associated with the repeated use of extract phases already used in previous cycles of purification as extractant. This leads to the production of several, different, deteriorating from cycle to cycle, degrees of purification: high, medium and low-purity, which is unacceptable in the conditions of strict standards to limit the content of sulfur compounds in motor fuels and is not economically feasible, since there is a need for additional cleaning of medium - and uncleaned fuel until presentation, as well as washing and neutralization of the resulting extractant residue.

Moreover, even when mixing all the cleaned fuel streams, fuel with low quality characteristics is obtained: total sulfur content 0.330% wt., Total nitrogen content 3.5 mg / kg, total aromatic hydrocarbons 8.37% wt. (line 5, table 1, p. 13 of the description of the closest analogue).

Also known are devices that are used for refining petroleum products.

A device for removing contaminants from petroleum products, containing a high pressure tank in communication with a source of contaminated oil and solvent, as well as with a source of reagent that increases flocculation. The tank contains an outlet for contamination in the lower part, a decanter for removing refined oil and solvent, an outlet associated with the inlet for gas circulation [RU 2140433 C1, priority 02/14/1995].

The disadvantage of this device is the insufficiently high quality of refining of petroleum products.

The closest technical solution to the claimed device is a device for producing commercial diesel fuel from sour diesel fractions [RU 2514916 C1, priority 28.12.2012]. The device contains three reactors for cleaning independent flows of fuel fractions, each reactor being an extraction reactor with an input for supplying the corresponding extractant and outputting the corresponding extract phase. In this case, the output of the extract phase from the first reactor is connected to the input of the extractant to the second reactor, the output of the extract phase from the second reactor is connected to the input of the extractant to the third reactor, and the output of the extract phase from the third reactor is connected to the washing unit of the extract phase, and the output of purified fuel fractions of all three streams it is connected to a block for their neutralization with the withdrawal of commercial fuel from it.

The disadvantages of the closest analogue are the low quality of fuel cleaning. Another drawback of the closest analogue is a three-line single-stage purification of fuel, leading to an imbalance in the rate of use of the extractant: the processing time of the first fuel stream is 30 minutes, the secondary extractant treatment of the medium-cleaned stream is about an hour, and the processing of a non-cleanable stream with a tertiary estragent takes several hours. As a result of the imbalance, the problem of accumulation of the secondary extractant arises and, as a result, the overall performance of the commercial diesel fuel production device decreases.

The objective of this group of inventions is to develop a simple and effective method and device for cleaning dark, substandard diesel and heating oil from unwanted impurities in one processing cycle of the initial fuel fraction, which allows to obtain a single stream of purified fuel, as well as reduce the amount of extractant used - sulfuric acid and reduce the amount of hard-to-utilize residue formed after extraction (acid tar).

The technical result, which this group of inventions aims to achieve, is to improve the quality of cleaning dark, substandard diesel and heating oil, improve its physico-chemical properties, giving it a presentation. The technical result also consists in simplifying the cleaning method by using only one stream of purified fuel.

The technical result is achieved by the fact that the method of purification of substandard fuel from asphaltenes and sulfur compounds by mixing the initial fuel fraction with an extractant, which is used as concentrated sulfuric acid, followed by separation of the resulting raffinate fraction, processing it with a neutralizing reagent and water, is characterized in that before by mixing the initial fuel fraction is subjected to ozone oxidation, and the fuel is cleaned in a single flow in one cycle, while the extractant is used once every cycle, while as a neutralizing agent using soda ash and after treatment with water raffinate fraction is subjected to filtration and dehydration.

The technical result is also achieved by the fact that a device for cleaning substandard fuel from asphaltenes and sulfur compounds, containing three reactors, is characterized in that it is equipped with a reservoir of the initial fuel fraction, an ozone generator, a cavitator, an extractant tank, a sludge collector, a waste collector, and a neutralizing tank reagent, a water tank, a centrifuge and a tank of finished purified fuel, while the reservoir of the initial fuel fraction is connected to the inlet of the fuel fraction cavitator a, the other input of which is connected to the ozone generator, and the output is connected to the input of the fuel fraction of the first extraction reactor, connected to the container for the extractant, and the extraction reactor is connected to the sludge collector by one output, and the output of the raffinate fraction of the second neutralization reactor, connected to a container for a neutralizing reagent, and the neutralization reactor is connected in one outlet to the waste collector, and the output of the raffinate fraction is connected to the inlet of the third water treatment reactor connected to the water tank, and the water treatment reactor is connected through a centrifuge to the tank of the finished purified fuel.

The invention is illustrated by figures 1 and 2. In FIG. 1 presents a schematic diagram of the inventive device in which the described method for cleaning substandard fuel from asphaltenes and sulfur compounds is carried out. In FIG. 2 presents a photograph of the claimed device.

The positions in figure 1 are indicated:

1 - reservoir of the original fuel fraction,

2 - ozone generator,

3 - cavitator,

4 - extraction reactor,

5 - capacity for extractant,

6 - sludge collector,

7 - waste collection,

8 - neutralization reactor,

9 - capacity for a neutralizing reagent,

10 - capacity for water,

11 - water treatment reactor,

12 - centrifuge,

13 - tank of finished purified fuel.

The arrows schematically show the movement of all flows in the inventive device for cleaning (fuel fraction, extractant, raffinate fraction, neutralizing reagent, etc.).

The inventive device for cleaning substandard fuel from asphaltenes and sulfur compounds contains three successively installed and operating reactors: a first extraction reactor 4, a second neutralization reactor 8, and a third water treatment reactor 11. The device is additionally equipped with a reservoir 1 of the initial fuel fraction, an ozone generator 2, a cavitator 3, a tank 5 for extractant, a sludge collector 6, a waste collector 7, a tank 9 for a neutralizing reagent, a tank 10 for water, a centrifuge 12 and a tank of finished purified fuel 13.

The reservoir 1 of the initial fuel fraction is connected to the input of the fuel fraction of the cavitator 3, the other input of which is connected to the ozone generator 2. Cavitator 3 has an output that connects to the input of the fuel fraction of the extraction reactor 4. Reactor 4 has two inputs, through one of which extractant from tank 5 is fed into it, and through the second, the fuel fraction from cavitator 3 is fed into it. Reactor 4 also has 2 an outlet, one of which is intended for the exit of waste from the reactor 4 to the sludge collector 6, and the second outlet, the reactor 4 is connected to the input of the raffinate fraction of the neutralization reactor 8. Through the second outlet, the raffinate fraction from the reactor 4 enters the reactor 8 for processing it with a neutralizing reagent. Reactor 8 has 2 inlets, one for supplying a neutralizing reagent into it from vessel 9, and the second for supplying a raffinate fraction from reactor 4 into it. Reactor 8 is connected to neutralization waste collector 7 in one outlet, and connected to the inlet of the third reactor with another outlet 11 water treatment. The reactor 11 has two inlets, one for supplying water from the tank 10 to it, and the second for supplying the raffinate fraction from the reactor 8. The reactor 11 is connected through a centrifuge 12 to the tank 13 of the finished purified fuel.

Cleaning substandard fuel using the claimed invention is as follows.

The estimated amount of fuel to be cleaned is supplied by the pump to the extraction reactor 4 through the cavitator 3, for which, for example, a vortex flow cavitator can be used. Ozone generated by the ozone generator 2, for example, a flare type ozone generator capable of operating in a start-stop mode, is introduced into the cavitator 3 by ejection. In the cavitator 3, the fuel flow swirls, the fuel particles are treated with ozone in the direction perpendicular to the flow movement, which increases the mixing speed of the fuel, increases the depth of oxidation of impurities by ozone and reduces the effect of destruction of the fuel particles by cavitation.

Then, concentrated sulfuric acid in an amount of 0.5-1.5% by weight of the fuel is fed into the extraction reactor 4 from the extractant tank 5 by a chemical pump. The same pump circulates for 40 minutes, sulfuric acid reacts with hydrogen sulfide, mercaptans, thiophenes, polycyclic sulfur- and nitrogen-containing impurities, converting them into water-soluble acid compounds and knocking out insoluble acid tar. After 30 minutes of settling, the settled acid tar layer is removed from the extraction reactor by a screw pump 4 into the sludge collector 6. The clarified fuel freed from asphaltenes (raffinate fraction) is fed by a chemical pump to the neutralization reactor 8, where it is also pumped from the tank 9 with a neutralizing reagent (calcined soda). For 40 minutes, the pump circulates the raffinate fraction and soda ash, as a result of which the remains of unreacted sulfuric acid, acid esters formed as a result of oxidation of alkenes by sulfuric acid, sulfonic acid and other hydrocarbon oxidation products enter into a neutralization reaction with soda ash with the formation of predominantly water-soluble corresponding salts; The pH of the medium is adjusted to 7. After 30 minutes of settling in the reactor 8, the separated lower water-salt layer is discharged into the waste collector 7, and the neutralized raffinate fraction from the neutralization reactor 8 is pumped to the water treatment reactor 11 by a chemical pump. The pump 11 supplies industrial water to the reactor 11 from the water tank 10 in an amount of 10% of the volume of purified fuel, then the pump emulsifies the water emulsion for 40 minutes, as a result of which the residual neutralization products that are not separated from the fuel in the neutralization reactor 8 are finally pass in the form of salts into the aqueous layer. Then, after 30 minutes of settling, the washed purified fuel is sent for filtration from insoluble salts and other mechanical impurities and dewatering from produced water in a centrifuge 12.

As a result of the implementation of the claimed group of inventions, a clarified purified commercial fuel with a high degree of purification enters the finished product warehouse 13 into the finished product warehouse: total sulfur content 0.135% mass., Total nitrogen content 1.8 mg / kg, total aromatic hydrocarbons content 3.75% mass . with a loss of not more than 10% of the total mass of cleaned fuel.

Claims (2)

1. The method of purification of substandard fuel from asphaltenes and sulfur compounds by mixing the initial fuel fraction with an extractant, which is used concentrated sulfuric acid, followed by separation of the resulting raffinate fraction, processing it with a neutralizing reagent and water, characterized in that before mixing the initial fuel fraction subjected to ozone oxidation, and the fuel is cleaned in a single flow in one cycle, while the extractant is used in each cycle once, while not The neutralizing reagent uses soda ash, and after treatment with water, the raffinate fraction is filtered and dehydrated. 2. A device for cleaning substandard fuel from asphaltenes and sulfur compounds, containing three reactors, characterized in that it is equipped with a reservoir of the initial fuel fraction, an ozone generator, a cavitator, an extractant tank, a sludge collector, a waste collector, a neutralizing reagent tank, and a water tank , a centrifuge and a tank of finished purified fuel, while the reservoir of the initial fuel fraction is connected to the input of the fuel fraction of the cavitator, the other input of which is connected to the ozone generator a, and the outlet is connected to the inlet of the fuel fraction of the first extraction reactor connected to the container for the extractant, the extraction reactor being connected at one outlet to the sludge collector and the other outlet to the inlet of the raffinate fraction of the second neutralization reactor connected to the neutralizing agent tank, the neutralization reactor connected to a waste collector in one outlet, and connected to the inlet of a third water treatment reactor connected to a water tank, with the outlet of the raffinate fraction purification is connected through a centrifuge to the tank of finished purified fuel.

Images