BG109247A - Method for the conversion of coal into fuels - Google Patents

Abstract

The method is applied in the chemical and the petrochemical industries for the manufacture of synthesis gas, which is a raw material for chemical products and synthetic motor fuels. Synthesis gas is produced from high viscosity water-and-coal fuel at higher process efficiency. The method comprises preparation of the water-and-coal mixture and its gasification in two stages. The first one occurs in a vertical stream tubular heat exchanger of a gasification column, and the second one in a heated reactor with the production of synthesis gas and solid residues. There follows a stage of catalytic treatment of synthesis gas into motor fuels. The steam-gas-and-coal mixture in the heat exchanger is subjected to the effect of modulated high frequency fields from 1 to 50 MHz at modulation frequencies ranging from 1 to 200 kHz. In the reactor the steam-, gas- and coal mixture is subjected to the effect of plasma from single electrode high frequency discharges at temperatures ranging from 600 to 800 degrees C. The synthesis gas produced is subjected to electrochemical purification from sulphur and nitrogen compounds, purification from chemical impurities, is compressed and is subjected to conversion by means of polyfunctional catalyst containing iron, zinc and molybdenum oxides in combination with a carrier of aluminium, its oxides and aluminium phosphate. It is possible that the gasification process of the steam-gas-and-coal mixture in the reactor could be carried out in the presence of carbon steam, conversion catalysts applied over the heat insulation coating of the inner reactor walls.

Description

The invention relates to a method for thermal and thermochemical processing of coal in synthesis gas, applicable in the chemical and petrochemical industries for the production of synthesis gas - raw material for the production of various types of chemical products and synthetic motor fuels.

BACKGROUND OF THE INVENTION

A method of solid fuel processing is known, including the saturation of coal with hydrogen at high temperatures (above 400 ° C) and a pressure of 50 to 300 at, with subsequent separation of liquid and solid intermediates. Subsequently, the liquid products are subjected to hydrogenation enrichment with subsequent production of components of high-octane gasoline, diesel fuel, jet fuel and gas turbine fuel, phenols, nitrogen bases and other products [Chulkov VV, Motornme fuels: resources, quality, substitutes , M. 1998].

The disadvantage of this known method, as well as all known methods for the production of coal fuels by hydrogenation, is the need to use significant amounts of hydrogen. The volume of hydrogen required for this purpose exceeds, on average, three times the volume of the fuels obtained. This factor limits the widespread use of such productions.

A method is also known for the preparation of coal-based motor fuels by processing them to synthesis gas (a mixture of CO + H ₂ ) with subsequent processing into motor fuels [Setterfield Ch. pp.].

In this method, the mixture of hydrogen and carbon monoxide required for production is obtained by treating coal with water vapor and oxygen.

There is also a known method for the thermal processing of solid fuels. •; · · · · · · · · · · · · · · · · · · · · · · · ·. ·; ·· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

an arc in order to have the velocity vector of the mixture thus described being parallel to the axis of the arc. In this process, the average synthesis gas temperature is maintained at 1200 - 1700 ° C by adjusting the arc power. In this method, water vapor and oxygen are used as the oxidant in the ratio: water vapor 15-45% and oxygen 85 55% [FR2491490]. The use of oxygen as an oxidant results in the ballasting of carbon dioxide synthesis gas, which is a product of the carbon-oxygen interaction, and a special installation is also required to produce oxygen. All this leads to additional energy consumption, since it is necessary to purify the synthesis gas, and the production and storage of oxygen in the required volume leads to increased energy consumption.

Maintaining the temperature of the resulting synthesis gas at the expense of regulating the power of the arc is low efficient, unreliable and complicated, since the heat is released into the reactor both at the expense of burning the coal in oxygen and at the expense of energy. , which is separated from the electric arc and only one heat source is regulated - the electric arc.

These disadvantages significantly reduce the technical and economic indicators and complicate the process as a whole.

A method of converting coal into synthesis gas is known, comprising the preparation of coal in the form of a colloidal-dispersed combustion system with an average surface particle size of the dispersed phase not greater than 1 pm, gasification of the resulting single-stage combustion mixture in a reactor with vertically positioned tubes in which the said fuel mixture is fed, with the temperature of the coolant being fed into the coolant in 9 · 9 · 9 · 9 · 9 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ora is maintained in the range 400 1000 ° C and the temperature in the pipes is in the range 200 - 800 ° C [RU2190661]. The disadvantage of this method is its low energy efficiency in the synthesis gas production process, since:

- preparation of the colloidal-dispersed combustion system is accompanied by grinding not only the organic but also the mineral component of the coal to an average surface size of the particles of the dispersed phase not exceeding 1 pm, which significantly increases the energy consumption for grinding them ;

- the independent heating of the coolant supplied to the reactor tube in the annulus up to 1000 ° C in the presence of hot air, cooling the synthesis gas after the tube cooler, leads to excessive energy consumption for heating the dispersed combustion system;

- the use of a straight-line pipe cooler to cool the synthesis gas, instead of a counter-current, is also inefficient.

The recommended temperature range for gasification from 200 to 800 ° C does not ensure the efficient running of the process using low-reaction coals such as anthracite.

In addition, in the non-deterministic mass ratio of coal and water in the prepared dispersed-colloidal fuel system, it is not possible to determine the energy consumption for the synthesis gas.

There is also a known Plasma-Thermal Method for Coal-to-Gas Processing, which involves the preparation, heat treatment and gasification of coal by means of plasma in a plasma reactor, the gasification process being carried out in three stages, two of which take place in tube heat exchangers, and the third final step takes place directly in the volume of the plasma reactor simultaneously with the process of high temperature pyrolysis in the presence of a reagent. The preparation of the coal is done by dispersing them in methanol water, which is used in the preparation of coal. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · - - - - - - - - - - - - -. reactor space, and before the second gasification step, the coal slurry is heated to 900 - 1100 ° C in the synthesis gas stream discharged from the plasma reactor. Water vapor is used as a reagent for high temperature pyrolysis, which is injected into the reaction zone using plasma sources. The synthesis gas obtained in the plasma reactor is cooled and purified from impurities in a centrifugal-bubbler apparatus by means of atmospheric air and water, the atmospheric air subsequently being used with a portion of the synthesis gas in the combustion apparatus of the gasification column and the water supplied to a dispersing apparatus for preparing the coal slurry. [RU2047650].

The disadvantage of this method is the complexity of the technological process, which is carried out in three stages with preheating of the coal slurry to 200 - 300 ° C, with simultaneous combustion of part of the synthesis gas and using the synthesis gas extracted from the plasma reactor, heated up to 2200 - 2700 ° C. For the purposes of preheating and carrying out the first and second gasification steps in the temperature range 900 - 1100 ° C, it is sufficient to use the heat stored in the synthesis gas discharged from the plasma reactor.

In this method, too, the consumption of energy for the production of synthesis gas is increased, which is related to the introduction into the plasma reactor of a vapor-carbon suspension consisting of carbon monoxide, carbon dioxide, hydrogen, water vapor and unreacted carbon particles. Water vapor is used as a reagent in the plasma reactor, which results in additional ballasting of the gaseous products by gasification with the gas. water vapor and simple hydrocarbons that form temperatures of 2200 - 2700 ° C.

The scheme for the interaction of the plasma vapor jets with the jets of the gasifier mixture and the organization of the return of unreacted organic carbon particles to the reaction zone for their full conversion to gas are equally applicable to the solid mineral carbon particles, which do not react with the vapor phase, as a result of which they accumulate in the high temperature zone of the plasma reactor. Due to the high temperatures and long residence in the plasma reactor, the metal oxides that make up the mineral composition of the coal are melted down and the possibility of chemical interaction with carbon is created, resulting in metals, carbides and carbon oxides, which consumes a significant amount of energy, which generally reduces the calorific value of synthesis gas at the expense of saturation with carbon oxides.

Closest to the present invention is the method of producing synthesis gas from a water-coal suspension [RU2233312] comprising the preparation and gasification of a water-coal suspension, the gasification being carried out in two steps, the first of which is carried out in a vertical counter-flow tube heat exchanger of the gasification and the second in a ultra-high frequency (microwave reactor) heating reactor. In this method, the preparation of the coal slurry is carried out by dispersing the coal in the aqueous phase to a particle size of the solid phase from 10 to 30 pm with a mass concentration of the organic component of the coal in the coal slurry from 32% to 48%. In the first gasification step, the resulting coal slurry is directed to a heat exchanger of the gasification column at a pressure of 0.5 -10 MPa, where it is heated to a temperature of 500-700 ° C until a steam-coal slurry is formed. Further, this suspension is targeted at • 4 4 4 · 4 • 444

4 · · · · · · · · · · · · · 4 · · · · 4 · · 4 · · · 44 44

444444 4 • 444 ·· 44 4 44 ··· steam mill for crushing the solid phase particles to a finely dispersed state 1-3 pm. The steam-to-coal slurry, broken down to a predetermined size, is fed to a second stage of gasification, into a microwave reactor, where it is heated to a temperature of 700 - 1500 ° C until synthesis gas is obtained. The resulting synthesis gas is cooled in the heat exchanger of the gasification column with the help of the water-coal slurry entering the heat exchanger and purified from the ballast substances with water, which is used for the preparation of the water-coal slurry.

Unlike the method described in patent [RU2190661], the gasification process carried out here is carried out in two steps instead of three, which allows to simplify the synthesis gas production technology. In addition, the process of preparation of the coal slurry is carried out by fragmenting the initially deposited coal by dispersing it in the aqueous phase until separation of the associated organic and mineral particles of the coal (up to 10-30 μπι solid phase particles), which avoids the crushing of the hardest and most difficult to disperse mineral coal particles to a fine dispersion fraction of less than 1 μπι, which significantly reduces the energy consumption for the preparation of the water-coal slurry enzyme.

Moreover, the mass concentration of the organic part of the coal in the coal slurry is 32% - 48%, which provides low viscosity values of the coal slurry even at the size of the coal particles in the range of 10-30 pm, and as a result increases the efficiency of the synthesis gas production process.

In the first gasification step, the resulting coal-water slurry under pressure of 0.5 - 10 MPa is heated in a heat exchanger to a temperature of 500 700 ° C to form a steam-coal slurry. This is how · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · .

The gasification process is more intense than gasification at atmospheric pressure.

The use of a steam mill is not associated with additional energy consumption for crushing, as it uses energy accumulated in the superheated steam-coal suspension in the form of high pressure (0.5 - 10 MPa) and an elevated temperature of 500 - 700 ° C. It should be noted that mainly the porous particles of the coke residue of the organic constituent of coal are subjected to fragmentation, both in the case of particle collisions with each other and in the difference between the pressure inside the particles and the pressure in the working chamber of the coal. the mill. The particles contained in the mineral composition of the coal are further refined to a much lesser extent, since their porosity is practically absent.

The second stage of gasification takes place in a microwave reactor in which, under the influence of ultra-high-frequency electromagnetic radiation, the entire reaction mass of the steam-coal suspension is heated to temperatures of 700 - 1500 ° C. As a result of this, at the expense of the absorption of microwave energy, the gasification process of the steam-coal suspension is accompanied by the further dispersion of the solid particles, which leads to the intensification of the gasification process and to a fuller use of carbon.

The disadvantage of this method, which is a prototype, is that the process is carried out at such a high temperature range that, to an increase in energy consumption, reducing the economic efficiency of the process, partial melting of the mineral components of coal and the formation of soot.

Other disadvantages of the method are the low intensity of the synthesis gas production process and the technical complexity of introducing microwave radiation into the reactor via waveguides.

It is an object of the invention to provide a method for processing coal into fuels with a high efficiency of the process of producing synthesis gas from high-viscosity coal water.

SUMMARY OF THE INVENTION

This task is created by creating a method of processing coal into fuels, which involves the preparation of a water-coal mixture and its gasification in two stages. The first one flows into a vertical flow tube heat exchanger on a gasification column, and the second into a heated reactor to produce synthesis gas and solid residues. The next step of catalytic processing of synthesis gas in motor fuels, it is characteristic that the steam-coal mixture in the heat exchanger is exposed to modulated high-frequency fields in the frequency range from 1 MHz to 50 MHz at modulation frequencies in the range from 1 KHz to 200 KHz . In the reactor, the vapor-carbon mixture is exposed to plasma from single-electrode high-frequency discharges at a temperature of 600 - 800 ° C. The resulting synthesis gas is subjected to electrochemical purification from sulfur and nitrogen compounds, purification from chemical impurities, compressed and subjected to conversion using a polyfunctional catalyst containing iron oxides, zinc and molybdenum in combination with a carrier aluminum, their oxides and aluminum phosphate.

The gasification process of the gas-carbon mixture in the reactor may be carried out in the presence of catalysts for the steam conversion of carbon deposited on the thermal insulation coating of the inner walls of the reactor.

An advantage of the invention is that the method of processing coal into fuels has increased the efficiency of the process of producing synthesis gas from high-viscosity coal water.

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DESCRIPTION OF THE FIGURES Attached ..............

The invention is illustrated in more detail by an exemplary embodiment of an installation for carrying out the method of processing coal into fuels shown in the figure which is a diagram of that installation.

EXAMPLE IMPLEMENTATION AND ACTION OF THE INVENTION

The installation of the figure is one possible implementation for implementing the method. Unlike the prototype, the steam-coal mixture is fed by pump 1 into a vertical counter-flow tube heat exchanger 2 of the gasification column 3 and further processed by high-frequency electromagnetic fields. The supply of high-frequency energy to the coal-gas mixture is carried out by means of metal bars 4, which are completely covered with dielectric materials (for example, ceramics, quartz) 5. These metal bars 4 are connected to a high-frequency generator 6, providing in working mode the transmission of high-frequency power in vapor-carbon mixture at carrier frequency 1-50 MHz and modulation frequency 1- 200 KHz. Intensive absorption of high-frequency power from the steam-coal mixture takes place in the specified frequency range. In this way, the process of gasification of the hydrocarbon fuel is controlled by changing the temperature of the process, and the intensification of the mixing of the treated fuel by modulated high-frequency electromagnetic waves is also carried out.

The second step of the method involves the additional gasification process of the steam-coal mixture, which is fed through pipelines 7 into the reactor8, in which the inner walls are covered with a special material based on a refractory coating having not only low thermal conductivity and low heat capacity, but also catalytic properties of the reactor in the vapor conversion of carbon to synthesis gas. The use of such material, being a catalyst, allows the process of carbon gasification to be accelerated at relatively low temperatures (up to 400 ° C), which, under other conditions of equal conditions, increases the productivity of the installation for production of synthesis gas up to 1.5 - 2 times.

In addition, the reactor undergoes further treatment of the vapor-carbon mixture by a highly non-equilibrium plasma created by single-electrode high-frequency discharges generated by specially designed electrodes with the shape of a blade 9 inside the generator, regardless of the chemical composition of the vapor-carbon mixture and the thermal regime.

The supply of microwave energy to the above electrodes is carried out by high frequency generators 10. They operate at a frequency of 1-40 MHz and a modulation frequency of 0.5 - 50 KHz.

Cg

In the reactor, the vapor-carbon mixture is exposed to both plasma of single-electrode discharges and high-frequency electromagnetic fields, whereby fullerenes, fullerenes arise, increasing the amount of synthesis gas obtained from the treated mixture.

Features of the invention are:

- Utilization of high-frequency energy in the two stages of synthesis gas synthesis from a coal-gas mixture;

- Use of highly unbalanced single-electrode plasma

O high frequency discharge of the second stage of synthesis gas synthesis from a steam-coal mixture;

- Use of a coating on the inner walls of the reactor made of a refractory material having not only the chemical and mechanical resistance of the steam-coal mixture, but also the strong catalytic properties of the steam conversion of carbon;

- The conversion of synthesis gas to synthetic motor fuels takes place in the presence of a multifunctional catalyst containing oxides of iron, zinc and molybdenum, aluminum, its oxides and aluminum phosphate.

· · ···

11 ...

The implementation of the proposed method, compared to the prototype, there

a number of original technological methods and constructive solutions of technological processes, consisting of the following:

- Within the reaction gasification column (3), the synthesis gas production process is activated by means of modeled high-frequency fields, which allows the process temperature to be lowered to 500-800 ° C.

- Reactor 8 exerts an effect on the vapor-carbon mixture by plasma of single-electrode high-frequency discharges followed by the formation of fullerene-like compounds, which generally intensifies the gasification process of the treated mixture.

- The inner walls of the reactor 8 are lined with material having not only thermal insulation but also catalytic properties, which allows to increase the intensity of the synthesis gas production process from the steam-coal mixture and thus to shorten the processing time in the reactor.

The process of gasification of the steam-coal mixture is as follows:

The prepared charcoal mixture with particle sizes not exceeding 30 pm is supplied by pump 1 at a pressure of 0.1 - 3.0 MPa into a vertical counterflow tube heat exchanger 2 of the gasification column 3. In the gasification column 3, the coal mixture is heated to 200 - 400 ° C. to the formation of a coal-vapor suspension, which is treated by modulated high frequency fields. The microwave power is supplied by metal rods 4 coated with dielectric material 5. The metal rods are directly connected to the high-frequency generators 6, which operate on a carrier frequency of 1-50 MHz and a modulation frequency of 1 - 200 KHz.

4 * 4 ···

4

The gasification process, which takes place at the expense of the absorption of electromagnetic energy, begins in the middle of the reactor, and takes place most intensively in the upper part of the reactor at temperatures of 500 - 700 ° C.

The partially gasified vapor-carbon slurry is fed through the pipelines 7 into the reactor 8 through a static mixer 11, where, under the influence of high-frequency fields and plasma from single-electrode discharges, the vapor-carbon mixture is heated to a temperature of 500 - 800 ° C. The inner walls of the reactor 8 are lined with a heat-insulating coating on the outer surface, which has a layer of catalyst using

in the steam-to-carbon conversion.

The synthesis gas obtained in the reactor 8, together with the ballast substances, enters the interstitial space of the gasification column 3, where the water-coal mixture entering the tubular part of the heat exchanger is used as a cooler. After passing through the heat exchanger, the synthesis gas is fed into a device for cleaning 12, for example a centrifugal-bubbling apparatus in which, in direct contact with cooling water, the synthesis gas is cooled to ambient temperature and the ballast substances of the products of gasification (water vapor, ash particles of coal, hydrogen sulfide, carbon dioxide, etc.). The purified synthesis gas is pumped with a compressor and piped to consumers. The purified water is fed to the circulating water pipeline. The ash residues from the gasification are removed from the bottom of the gasification column and sent for further processing. The mass ratio between water and the organic part of the solid phase of the coal-carbon mixture is determined by the condition that the water content must exceed by 10-20% the amount of water required according to the stoichiometric equation of the reaction of gasification of carbon with water vapor and depends on the content of carbon in coal [RU2233312]. Massively • * * ·

13 ...

• · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Carbon Ratio in Coal within the limits of 0.96 - 0.6 the mass concentration of coal in the coal mixture is approximately 32 48%.

The resulting synthesis gas is directed for electrochemical and plasma-chemical treatment at approximately 600 ° C for maximum removal of sulfur and nitrogen compounds. The synthesis gas is then cooled, cleaned of chemical impurities, compressed and directed to a hydrocarbon synthesis reactor at 300 ° C and 3 MPa pressure. The synthesis of liquid hydrocarbons takes place in the presence of a multifunctional catalyst containing oxides of iron, zinc and molybdenum in combination with a carrier - aluminum, its oxides and aluminum phosphate. The total amount of synthetic fuels produced is 190 g / nm ³ synthesis gas at 90% conversion of carbon oxides.

Claims (2)

1. A method of processing coal into fuels involves the preparation of a water-coal mixture and its gasification in two steps, the first of which is in a vertical flow tube heat exchanger on a gasification column and the second in a heated reactor to produce synthesis gas and solid residues, as well as a step of catalytic processing of synthesis gas in motor fuels, characterized in that the steam-coal mixture in the heat exchanger is exposed to modulated high-frequency fields in the frequency range from 1 MHz to 50 MHz at frequencies of the modulation in the range from 1 KHz to 200 KHz, and in the reactor the vapor-carbon mixture is exposed to plasma from single-electrode high-frequency discharges at a temperature of 600 - 800 ° C, and the resulting synthesis gas is subjected to electrochemical purification from the sulfur and nitrogen compounds. , impurities, compressed and transformed with a polyfunctional catalyst containing oxides of iron, zinc and molybdenum in combination with a carrier - aluminum, its oxides and aluminum phosphate. 2. The method according to claim 1, characterized in that the gasification process of the gas-carbon mixture in the reactor is carried out in the presence of catalysts for the steam conversion of carbon deposited on the thermal insulation coating of the inner walls of the reactor.