CN111621340B

CN111621340B - High-efficiency catalytic gasification system and method for coal

Info

Publication number: CN111621340B
Application number: CN202010491124.XA
Authority: CN
Inventors: 李克忠; 武恒; 毛燕东; 芦涛; 刘雷
Original assignee: ENN Science and Technology Development Co Ltd
Current assignee: ENN Science and Technology Development Co Ltd
Priority date: 2020-06-02
Filing date: 2020-06-02
Publication date: 2022-01-28
Anticipated expiration: 2040-06-02
Also published as: CN111621340A

Abstract

The present disclosure relates to the technical field of coal gasification, and provides a high-efficiency catalytic gasification system and method for coal. It includes a mortar gasification unit, a catalytic gasification unit and a catalytic pyrolysis unit; the catalytic pyrolysis unit is used to feed the raw coal and the high-temperature crude gas generated by the catalytic gasification unit, and the raw coal and the high-temperature crude gas undergo pyrolysis and methanation. The reaction generates coal char, crude gas, tar and coal ash; the mortar gasification unit is used for feeding oxygen, water, the ash generated by the catalytic gasification unit and the coal ash generated by the catalytic pyrolysis unit, oxygen, water, furnace ash and The coal ash undergoes combustion reaction, coal gasification reaction and water gas shift reaction to generate high temperature wet gas and ash; Coal gasification reaction, water-gas shift reaction and methanation reaction of coal gas and coal char generate high-temperature crude gas and furnace ash; realize high carbon conversion rate and improve tar and methane yield.

Description

High-efficiency catalytic gasification system and method for coal

Technical Field

The disclosure relates to the technical field of coal gasification, in particular to a high-efficiency catalytic gasification system and method for coal.

Background

The realization of clean and efficient utilization of coal is a subject of continuous exploration in the energy technology industry. With the technological progress, coal gasification gradually becomes one of the main ways of high-efficiency and clean utilization of coal. The prior coal gasification technology mainly adopts two-stage furnace brown coal gasification, crushed coal pressure gasification, high-pressure fluidized bed gasification, coal water slurry entrained flow bed gasification and pulverized coal gasificationEntrained flow bed gasification and the like. The gasification temperature and pressure requirements of the coal water slurry entrained flow bed gasification and pulverized coal entrained flow bed gasification processes are relatively high, and synthesis gas (CO and H) is mainly produced₂) When the catalyst is used for synthesizing chemicals, the carbon conversion rate is high, but byproducts such as methane, tar and the like do not exist. The gasification temperature and pressure of the high-pressure fluidized bed gasification process are lower than those of the entrained flow gasification process, and although the coal gas product contains methane, the proportion is relatively low, and the carbon conversion rate is not high. The crushed coal pressure gasification process can produce tar and a certain content of methane products, but the raw materials are mainly lump coal, and the carbon conversion rate is lower than that of the entrained flow bed gasification process. The two-stage furnace lignite gasification process can produce more tar and coal gas with high methane content, but the carbon conversion rate is only 50-60%.

The gasification technology is restricted by raw materials, operation conditions and the like, can not simultaneously meet the technical requirements of high carbon conversion rate, high tar, high methane generation rate and the like, can not realize the development targets of staged conversion and cascade utilization of coal advocated at present, and influences the applicability and the economical efficiency of the gasification technology to a certain extent.

Disclosure of Invention

In order to solve the technical problems or at least partially solve the technical problems, the present disclosure provides a system and a method for high-efficiency catalytic gasification of coal, which achieve high carbon conversion rate and improve tar and methane yield.

The utility model provides a high-efficient catalytic gasification system of coal, including mortar gasification unit, catalytic gasification unit and catalytic pyrolysis unit; the catalytic pyrolysis unit is used for introducing raw material coal and high-temperature raw gas generated by the catalytic gasification unit, and the raw material coal and the high-temperature raw gas are subjected to pyrolysis reaction and methanation reaction to generate coal coke, raw gas, tar and coal ash; the mortar gasification unit is used for introducing oxygen, water, furnace dust generated by the catalytic gasification unit and coal ash generated by the catalytic pyrolysis unit, and the oxygen, the water, the furnace dust and the coal ash generate combustion reaction, coal gasification reaction and water gas shift reaction to generate high-temperature wet coal gas and ash slag; the catalytic gasification unit is used for introducing high-temperature wet coal gas generated by the mortar gasification unit and coal coke generated by the catalytic pyrolysis unit, and the high-temperature wet coal gas and the coal coke are subjected to coal gasification reaction, water gas shift reaction and methanation reaction to generate high-temperature raw coal gas and furnace dust; the reaction temperatures of the mortar gasification unit, the catalytic gasification unit and the catalytic pyrolysis unit are decreased gradually.

Optionally, the system further comprises a separation unit and a mortar preparation unit, wherein the separation unit is used for separating crude gas, tar and coal ash generated by the catalytic pyrolysis unit; the mortar preparation unit is used for preparing mortar from the coal ash separated by the separation unit and the furnace ash generated by the catalytic gasification unit, and the prepared mortar is introduced into the mortar gasification unit.

Optionally, the system further comprises a catalyst recovery unit, wherein the catalyst recovery unit is used for recovering the catalyst in the furnace ash generated by the catalytic gasification unit and the coal ash generated by the catalytic pyrolysis unit, and the furnace ash and the coal ash recovered by the catalyst are introduced into the mortar preparation unit.

Optionally, a gas-solid separation unit is arranged between the catalytic pyrolysis unit and the separation unit, an inlet of the gas-solid separation unit is connected with the catalytic pyrolysis unit, a gas outlet of the gas-solid separation unit is connected with the separation unit, and a dust outlet of the gas-solid separation unit is connected with the catalytic gasification unit.

Optionally, a waste heat boiler unit is arranged between the catalytic gasification unit and the catalytic pyrolysis unit, and the waste heat boiler unit is used for exchanging heat and cooling the high-temperature raw gas introduced into the catalytic pyrolysis unit by the catalytic gasification unit.

Alternatively, the reaction temperature of the mortar gasification unit is 850 to 1300 ℃.

Optionally, the reaction temperature of the catalytic gasification unit is 650 to 800 ℃.

Optionally, the reaction temperature of the catalytic pyrolysis unit is 400 to 600 ℃.

The invention also provides a high-efficiency catalytic gasification method of coal, which comprises the following steps:

step one, raw material coal and high-temperature crude gas generated by a catalytic gasification unit are introduced into a catalytic pyrolysis unit, the raw material coal and the high-temperature crude gas are subjected to a pyrolysis reaction to generate coal coke, crude gas, tar and coal ash, wherein the coal coke is introduced into the catalytic gasification unit, and the coal ash is introduced into a mortar gasification unit;

introducing oxygen and water into the mortar gasification unit, wherein the oxygen, the water, the furnace ash and the coal ash are subjected to combustion reaction, coal gasification reaction and water gas shift reaction to generate high-temperature wet coal gas and ash slag, and the high-temperature wet coal gas is introduced into the catalytic gasification unit;

and step three, performing coal gasification reaction, water gas shift reaction and methanation reaction on the high-temperature wet coal gas and the coal coke in the catalytic gasification unit to generate high-temperature raw coal gas and furnace ash, wherein the furnace ash is introduced into the mortar gasification unit in the step two, and the high-temperature raw coal gas is introduced into the catalytic pyrolysis unit in the step one.

The coal coke, the crude gas, the tar and the coal ash generated by the catalytic pyrolysis unit are firstly introduced into a gas-solid separation unit for gas-solid separation, and then introduced into a separation unit;

the separation unit separates carbon monoxide, hydrogen and methane in the crude gas generated by the catalytic pyrolysis unit to obtain a gas product, separates the generated tar to obtain a tar product, and separates coal ash to be introduced into the catalyst recovery unit;

the furnace ash generated by the catalytic gasification unit and the coal ash separated by the separation unit are firstly introduced into a catalyst recovery unit for catalyst recovery, and then introduced into a mortar preparation unit, and the prepared mortar is introduced into a mortar gasification unit;

the high-temperature crude gas generated by the catalytic gasification unit is firstly introduced into the waste heat boiler unit for heat exchange and temperature reduction, and then is introduced into the catalytic pyrolysis unit.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages: the mortar gasification unit is used as a gas supply and heat supply unit of the system and provides required steam, coal gas and heat for the whole system, wherein combustion reaction, coal gasification reaction and water gas shift reaction mainly occur; the catalytic gasification unit is a core unit of the system and is a main reaction unit for generating a gas product, and high-temperature wet gas generated by the mortar gasification unit and coal coke generated by the catalytic pyrolysis unit are used for generating gas, wherein the gas mainly generates a coal gasification reaction, a water gas shift reaction and a methanation reaction; the catalytic pyrolysis unit is an important component of the system, is a generation unit of a tar byproduct of the system, can regulate and control the quality and yield of tar through operation, and simultaneously improves the generation rate of methane, wherein the pyrolysis reaction and the methanation reaction mainly occur; the three reaction units of catalytic pyrolysis, catalytic gasification and mortar gasification are creatively and orderly combined by the arrangement of the three units, cold materials are in reverse contact with hot coal gas in different reaction units, reasonable control of coal low-temperature pyrolysis, coal coke medium-temperature gasification and mortar high-temperature combustion reaction is realized, control of different reaction temperatures is realized, effective matching of heat is realized, graded conversion and cascade utilization of coal are realized, generated products of each reaction are effectively utilized, carbon conversion rate is improved, and maximization of target product quantities such as tar and methane is guaranteed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic view of a high-efficiency catalytic gasification system for coal provided by an embodiment of the disclosure.

Wherein, 1, a mortar gasification unit; 2. a catalytic gasification unit; 3. a catalytic pyrolysis unit; 4. a separation unit; 5. a mortar preparation unit; 6. a catalyst recovery unit; 7. a gas-solid separation unit; 8. a waste heat boiler unit.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that the embodiments and features of the embodiments of the present disclosure may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced in other ways than those described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.

As shown in fig. 1, the present disclosure provides a high-efficiency catalytic coal gasification system, which includes a mortar gasification unit 1, a catalytic gasification unit 2, and a catalytic pyrolysis unit 3; the catalytic pyrolysis unit 3 is used for introducing raw material coal and the high-temperature raw gas generated by the catalytic gasification unit 2, and the raw material coal and the high-temperature raw gas are subjected to pyrolysis reaction and methanation reaction to generate coal coke, raw gas, tar and coal ash; the mortar gasification unit 1 is used for introducing oxygen, water, furnace ash generated by the catalytic gasification unit 2 and coal ash generated by the catalytic pyrolysis unit 3, and the oxygen, the water, the furnace ash and the coal ash generate combustion reaction, coal gasification reaction and water gas shift reaction to generate high-temperature wet coal gas and ash; the catalytic gasification unit 2 is used for introducing high-temperature wet coal gas generated by the mortar gasification unit 1 and coal char generated by the catalytic pyrolysis unit 3, and the high-temperature wet coal gas and the coal char generate coal gasification reaction, water gas shift reaction and methanation reaction to generate high-temperature raw coal gas and furnace dust; the reaction temperatures of the mortar gasification unit 1, the catalytic gasification unit 2 and the catalytic pyrolysis unit 3 are sequentially decreased progressively.

Compared with the prior art, the mortar gasification unit 1 is used as a gas supply and heat supply unit of the system, and provides required steam, coal gas and heat for the whole system, wherein combustion reaction, coal gasification reaction and water gas shift reaction mainly occur; the catalytic gasification unit 2 is a core unit of the system, is a main reaction unit for generating a gas product, and generates gas by using high-temperature wet gas generated by the mortar gasification unit 1 and coal tar generated by the catalytic pyrolysis unit 3, wherein the gas mainly generates a coal gasification reaction, a water gas shift reaction and a methanation reaction; the catalytic pyrolysis unit 3 is an important component of the system, is a generation unit of a tar byproduct of the system, can regulate and control the quality and yield of tar through operation, and can improve the generation rate of methane, wherein a pyrolysis reaction and a methanation reaction mainly occur; the three reaction units of catalytic pyrolysis, catalytic gasification and mortar gasification are creatively and orderly combined by the arrangement of the three units, cold materials are in reverse contact with hot coal gas in different reaction units, reasonable control of coal low-temperature pyrolysis, coal coke medium-temperature gasification and mortar high-temperature combustion reaction is realized, control of different reaction temperatures is realized, effective matching of heat is realized, graded conversion and cascade utilization of coal are realized, generated products of each reaction are effectively utilized, carbon conversion rate is improved, and maximization of target product quantities such as tar and methane is guaranteed.

Specifically, the 'reverse contact of cold materials and hot coal gas in different reaction units' is embodied in the following two aspects:

firstly, materials in all units in the system are in reverse contact, normal-temperature raw coal enters a low-temperature catalytic pyrolysis unit 3, generated coal coke is introduced into a medium-temperature catalytic gasification unit 2, and generated furnace ash is introduced into a high-temperature mortar gasification unit 1, so that the step conversion of the coal is realized, and the yield of byproducts and the carbon conversion rate are improved; high-temperature wet gas generated from the mortar gasification unit 1 sequentially passes through the medium-temperature catalytic gasification unit 2 and the low-temperature catalytic pyrolysis unit 3 and is correspondingly in reverse contact with coal coke and raw material coal, so that gradient utilization of heat is realized, and the heat efficiency of the system is improved;

secondly, in the single reaction unit, in reverse contact, such as the catalytic pyrolysis unit 3, normal-temperature raw material coal is introduced from the middle upper part and moves downwards, the generated coal coke is discharged from the lower part, high-temperature raw gas is introduced from the lower part and flows upwards to generate new raw gas to be discharged; for example, in the catalytic gasification unit 2, the coal coke is introduced from the middle upper part and moves downwards, the generated furnace ash is discharged from the lower part, the high-temperature wet coal gas is introduced from the lower part, and flows upwards to generate new high-temperature crude coal gas to be discharged; the cold and hot materials are in reverse contact in a single reaction unit, so that the carbon conversion efficiency and the thermal efficiency of the system are improved.

In some embodiments, as shown in fig. 1, the system further comprises a separation unit 4 and a mortar preparation unit 5, wherein the separation unit 4 is used for separating crude gas, tar and coal ash generated by the catalytic pyrolysis unit 3; the mortar preparation unit 5 is used for preparing mortar from the coal ash separated by the separation unit 4 and the furnace ash generated by the catalytic gasification unit 2, and the prepared mortar is introduced into the mortar gasification unit 1. The device also comprises a catalyst recovery unit 6, wherein the catalyst recovery unit 6 is used for recovering the catalyst in the furnace dust generated by the catalytic gasification unit 2 and the coal ash generated by the catalytic pyrolysis unit 3, and the furnace dust and the coal ash recovered by the catalyst are introduced into the mortar preparation unit 5.

The furnace ash produced in the catalytic gasification unit 2 and the coal ash separated in the separation unit 4 contain a certain amount of catalyst, water may be introduced into the catalyst recovery unit 6 to dissolve the catalyst in water, the catalyst recovery unit 6 may be provided with a solid-liquid separation device to separate and recover the catalyst solution, or a digestion solution may be introduced to recover the water-insoluble catalyst, and the slurry obtained by separation may be introduced into the slurry preparation unit 5 to further prepare slurry.

In some embodiments, as shown in fig. 1, a gas-solid separation unit 7 is disposed between the catalytic pyrolysis unit 3 and the separation unit 4, an inlet of the gas-solid separation unit 7 is connected to the catalytic pyrolysis unit 3, a gas outlet of the gas-solid separation unit 7 is connected to the separation unit 4, and a dust outlet of the gas-solid separation unit 7 is connected to the catalytic gasification unit 2. The catalytic pyrolysis unit 3 can generate a certain amount of fly ash through reaction, the fly ash discharged from an air outlet at the upper part of the catalytic pyrolysis unit 3 can be separated and recovered as far as possible by adopting the gas-solid separation unit 7, and then the fly ash is introduced into the catalytic gasification unit 2 for gasification reaction, so that the carbon conversion rate is fully improved.

In some embodiments, as shown in fig. 1, a waste heat boiler unit 8 is disposed between the catalytic gasification unit 2 and the catalytic pyrolysis unit 3, and the waste heat boiler unit 8 is used for performing heat exchange and temperature reduction on the high-temperature raw gas introduced into the catalytic pyrolysis unit 3 from the catalytic gasification unit 2. The catalytic pyrolysis unit 3 is mainly used for carrying out pyrolysis reaction and methanation reaction, the temperature requirement is not high, so that the waste heat boiler unit 8 is arranged for properly cooling high-temperature raw gas, and the high-grade heat of the raw gas is utilized to produce byproduct steam, so that the technical economy is improved.

In some embodiments, the reaction temperature of the mortar gasification unit 1 is 850 to 1300 ℃. The slurry gasification unit 1 is subjected to a combustion reaction to supply heat to the whole system, so that the reaction temperature is high.

In some embodiments, the reaction temperature of catalytic gasification unit 2 is 650 to 800 ℃. The temperature is suitable for the reaction of high-temperature wet coal gas and coal coke to generate coal gas.

In some embodiments, the reaction temperature of the catalytic pyrolysis unit 3 is 400 to 600 ℃. The temperature is suitable for the pyrolysis reaction and the methanation reaction of the raw material coal and the high-temperature raw gas.

The high-efficiency catalytic gasification method for coal, provided by the disclosure, comprises the following steps:

firstly, raw material coal and high-temperature crude gas generated by the catalytic gasification unit 2 are introduced into the catalytic pyrolysis unit 3, and the raw material coal and the high-temperature crude gas are subjected to pyrolysis reaction to generate coal coke, crude gas, tar and coal ash, wherein the coal coke is introduced into the catalytic gasification unit 2, and the coal ash is introduced into the mortar gasification unit 1;

secondly, introducing oxygen and water into the mortar gasification unit 1, wherein the oxygen, the water, the furnace ash and the coal ash are subjected to combustion reaction, coal gasification reaction and water gas shift reaction to generate high-temperature wet coal gas and ash, and the high-temperature wet coal gas is introduced into the catalytic gasification unit 2;

and step three, performing coal gasification reaction, water gas shift reaction and methanation reaction on the high-temperature wet coal gas and the coal coke in the catalytic gasification unit 2 to generate high-temperature raw coal gas and furnace ash, wherein the furnace ash is introduced into the mortar gasification unit 1 in the step two, and the high-temperature raw coal gas is introduced into the catalytic pyrolysis unit 3 in the step one.

In some embodiments, the coal coke, the crude gas, the tar and the coal ash generated by the catalytic pyrolysis unit 3 are firstly introduced into the gas-solid separation unit 7 for gas-solid separation, and then introduced into the separation unit 4;

the separation unit 4 separates carbon monoxide, hydrogen and methane in the crude gas generated by the catalytic pyrolysis unit 3 to be used as a gas product, separates the generated tar to be used as a tar product, and separates coal ash to be introduced into the catalyst recovery unit 6;

the furnace ash generated by the catalytic gasification unit 2 and the coal ash separated by the separation unit 4 are firstly fed into a catalyst recovery unit 6 for catalyst recovery, and then fed into a mortar preparation unit 5, and the prepared mortar is fed into a mortar gasification unit 1;

the high-temperature crude gas generated by the catalytic gasification unit 2 is firstly introduced into the waste heat boiler unit 8 for heat exchange and temperature reduction, and then is introduced into the catalytic pyrolysis unit 3.

The specific working process of one embodiment of the invention is as follows:

the mortar gasification unit 1 is used as a gas supply and heat supply unit of the system and provides required steam, coal gas and heat for the whole system. The slurry gasification unit 1 adopts a gasification furnace which can be selected from but not limited to a single-nozzle water-coal-slurry gasification furnace, a multi-nozzle water-gas gasification furnace, a water-coal-slurry boiler and the like, the slurry with certain carbon content sent by the slurry preparation unit 5 and oxygen are fully reacted in the gasification furnace to generate high-temperature wet gas, the high-temperature wet gas is introduced into the catalytic gasification unit 2 from a gas outlet of the gasification furnace, ash is discharged from a discharge outlet, the gasification reaction temperature is 850-1300 ℃, and the reaction pressure is 4.5-6.0 MPa. When the carbon content of the mortar is low and is not enough to maintain the reaction temperature, the carbon content of the furnace ash can be increased by regulating the catalytic gasification unit 2, and the raw material coal can also be directly added into the mortar preparation unit 5.

The main components of the high-temperature wet coal gas are carbon dioxide, superheated steam, hydrogen and carbon monoxide, the temperature is 850-1300 ℃, and the pressure is 4.5-5.5 MPa. The main chemical reactions of the mortar gasification unit 1 are:

and (3) combustion reaction: c + O₂→CO+CO₂

Coal gasification reaction: c + H₂O→CO+H₂

Water gas shift reaction: CO + H₂O→CO₂+H₂。

The catalytic gasification unit 2 is a core unit of the system and is a main reaction unit for producing gas products. The fly ash sent by the coal coke and gas-solid separation unit 7 sent by the catalytic pyrolysis unit 3 and the high-temperature wet gas sent by the mortar gasification unit 1 fully generate catalytic gasification reaction in the catalytic gasification unit 2, so that the high-efficiency conversion of carbon in the coal coke and the fly ash is realized, high-temperature crude gas and furnace ash are generated, the high-temperature crude gas is introduced into the catalytic pyrolysis unit 3 from the gas outlet of the gasification furnace, and the furnace ash is discharged to the catalyst recovery unit 6 from the discharge port. The catalytic gasification unit 2 adopts a gasification furnace which can be selected from but not limited to a high-pressure fluidized bed, the reaction temperature is 650-800 ℃, and the reaction pressure is 3.5-4.5 MPa.

The retention time of the catalytic gasification reaction can be adjusted according to the requirement of the mortar gasification unit 1, so as to control the carbon content of the furnace ash, generally controlling the carbon content to be 10-35%, and simultaneously discharging the catalyst out of the gasification furnace along with the furnace ash into the catalyst recovery unit 6.

The high-temperature raw gas mainly comprises hydrogen, carbon monoxide, methane, carbon dioxide, steam and the like, the temperature is 650-800 ℃, and the pressure is 3.5-4.0 MPa. The main chemical reactions of the catalytic gasification unit 2 are:

coal gasification reaction: c + H₂O→CO+H₂

Water gas shift reaction: CO + H₂O→CO₂+H₂

Methanation reaction: CO + H₂→CH₄+H₂O。

The catalytic pyrolysis unit 3 is an important component of the system, is a generation unit of tar byproducts of the system, can regulate and control the quality and yield of tar through operation, and can improve the methane generation rate at the same time. The high-temperature raw gas sent by the catalytic gasification unit 2 is controlled by a waste heat boiler unit 8 to be cooled and fully contacted with the catalyst-loaded raw coal, the raw coal can be bituminous coal, the particle size of the raw coal is less than 5mm, the raw coal is loaded with an alkali metal catalyst, and the moisture of the dried raw coal is controlled to be less than 10%. The raw material coal is pyrolyzed rapidly to generate crude gas and coal coke rich in tar. The catalytic pyrolysis unit 3 can be selected from, but not limited to, a high-pressure fluidized bed, a fixed bed, a transport bed and the like, the pyrolysis reaction temperature is 400 to 600 ℃, and the pyrolysis pressure is 3.0 to 4.0 MPa. The main chemical reactions of the catalytic pyrolysis unit are:

and (3) pyrolysis reaction: coal hydrogen-rich and steam-rich environment → volatile component + tar + coal tar

Methanation reaction: CO + H₂→CH₄+H₂O。

Because the catalytic pyrolysis unit 3 is internally provided with the coal coke bed material with a certain height and containing the catalyst, carbon monoxide and hydrogen in the raw gas generated by catalytic gasification at the low temperature of 400-600 ℃ and the high pressure of 3.0-4.0 MPa can further generate methanation reaction, and the methane content in the gas is further improved.

The waste heat boiler unit 8 is positioned between the catalytic gasification unit 2 and the catalytic pyrolysis unit 3, and is mainly used for timely regulating and controlling the temperature of the high-temperature raw gas according to the coal quality characteristics and the operating temperature of the catalytic pyrolysis unit 3, and simultaneously recovering the heat of the high-temperature raw gas to produce a medium-pressure superheated steam as a byproduct for use by a system or power generation. The waste heat boiler unit 8 can be selected from, but not limited to, a vertical fire tube boiler or a horizontal fire tube boiler, and can be selected according to the dust content in the raw gas.

The gas-solid separation unit 7 and the separation unit 4 are post-treatment units of the whole system, and are mainly used for carrying out gas-solid separation and cooling on the crude gas sent from the catalytic pyrolysis unit 3, and the fly ash separated firstly returns to the catalytic gasification unit 2 for reuse, so that the carbon conversion rate of the system is improved. The gas-solid separation unit 7 can be selected from, but not limited to, a cyclone separator, a metal filter, a ceramic filter and a cloth bag filter, and can also be used in combination of several of the above. The separation unit 4 is mainly used for realizing effective separation of gas, water, oil and dust, wherein the gas is used as a coal gas product, the oil is used as a tar product, and the water and the dust are mixed into coal ash and enter the catalyst recovery unit 6. The separation unit 4 is generally a combination of several devices or systems, mainly composed of a cooler, a water washing tower, a separation tank, and the like.

The catalyst recovery unit 6 is mainly used for recovering the catalyst in the furnace dust and the coal slime, and the common method comprises the steps of recovering the soluble part of the catalyst by washing, digesting and recovering the insoluble part of the catalyst, and producing a catalyst solution product after washing and digesting to realize recycling;

the mortar preparation unit 5 receives the mortar from the catalyst recovery unit 6, and uniformly mixes the mortar, water, and additives by a mill to prepare mortar as a main raw material of the mortar gasification unit 1. Depending on the operational requirements of the mortar gasification unit 1, a certain amount of raw coal may also be added during the pulping process, the mortar concentration being typically controlled between 15% and 50%.

[ examples ] A method for producing a compound

The system and the method for the high-efficiency catalytic gasification of the coal are used for comprehensively converting and utilizing the soft coal without continuous channels. The mortar gasification unit 1 adopts a single-nozzle entrained flow bed, the operation temperature is 950 ℃, the operation pressure is 5.0MPa, the mortar concentration is 35 percent, the carbon content is 40 percent, the generated high-temperature wet coal gas with 900 ℃ and 4.8MPa is sent to the catalytic gasification unit 2, the high-temperature wet coal gas with 550 ℃ and 500 ℃ fly ash sent by the coal coke and gas-solid separation unit 7 sent by the catalytic pyrolysis unit 3 are subjected to catalytic gasification reaction in a high-pressure fluidized bed, the catalytic gasification temperature is controlled between 700 ℃ and 750 ℃, the pressure is 4.0MPa, the discharged furnace ash (the carbon content is controlled between 38 percent and 40 percent) is sent to the catalyst recovery unit 6, the generated high-temperature crude coal gas with 700 ℃ is cooled to 620 ℃ by the waste heat boiler unit 8 and then sent to the catalytic pyrolysis unit 3, the non-continuous-channel pulverized coal (the grain diameter is not more than 5mm) loaded with 12 percent of ECC-K01 catalyst is subjected to pressurized quick catalytic pyrolysis, the pyrolysis temperature is 565 ℃, the pressure is 3.8MPa, and the generated crude coal gas passes through the gas-solid separation unit 7, The separation unit 4 processes the products and finally divides the products into various products to be sent out of the system; the cooling system separates and collects tar products and sends the tar products to a tar storage tank, and the coal ash is sent to a catalyst recovery unit 6; the catalyst recovery unit 6 carries out catalyst washing and digestion recovery on the furnace ash and the coal ash, wherein the washing condition is 80 ℃, the normal pressure and the retention time are 20min, the digestion condition is 180 ℃, the saturated steam pressure and the retention time are 120min, the addition amount of a digestion agent is 45% of the weight of the furnace ash and the coal ash, the generated ECC-K01 catalyst solution product with the concentration of 40% is recycled, the catalyst recovery rate is 96%, and the mortar is sent to a mortar preparation unit to prepare mortar with the concentration of 40%. By the system and the method, efficient, clean and economic conversion of the non-continuous ditch coal is realized, and specific data are shown in table 1.

Comparative example 1

A multi-layer fluidized bed gasification reaction device in the prior art is adopted, unjoined channel pulverized coal (the particle size of the pulverized coal is less than or equal to 5mm) loaded with 12% of ECC-K01 catalyst is selected, the gasification temperature is 700-750 ℃, the pressure is 4.0MPa, a coal gas product rich in tar and methane is produced, the generated ash is subjected to catalyst recovery, the recovery rate reaches 95%, a catalyst solution product is recycled, and the specific data is shown in Table 1.

Comparative example 2

The method adopts a traditional crushed coal pressurized gasification reaction device, selects 5mm to 50mm of non-connected channel lump coal (the grain diameter is too large to load a catalyst), controls the gasification temperature to 700 ℃ to 750 ℃ and the pressure to 4.0MPa, and produces a coal gas product, wherein the specific data is shown in Table 1.

Table 1: running specific data

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-efficiency catalytic gasification system for coal, characterized in that, comprising a slurry gasification unit (1), a catalytic gasification unit (2) and a catalytic pyrolysis unit (3);

The catalytic pyrolysis unit (3) is used for feeding the raw coal and the high-temperature crude gas generated by the catalytic gasification unit (2), and the raw coal and the high-temperature crude gas undergo a pyrolysis reaction and a methanation reaction to generate char and crude gas. Coal gas, tar and coal ash; the raw coal is fed from the upper part of the catalytic pyrolysis unit and moves downward, and the generated char is discharged from the lower part of the catalytic pyrolysis unit; the high-temperature crude gas is produced by The lower part of the catalytic pyrolysis unit is passed through, and new crude gas is generated by flowing upward;

The slurry gasification unit (1) is used for feeding oxygen, water, furnace ash generated by the catalytic gasification unit (2) and coal ash generated by the catalytic pyrolysis unit (3), oxygen, water, furnace Ash and coal ash undergo combustion reaction, coal gasification reaction and water gas shift reaction to generate high temperature wet gas and ash;

The catalytic gasification unit (2) is used to pass the high-temperature wet coal gas generated by the slurry gasification unit (1) and the coal char generated by the catalytic pyrolysis unit (3), and the high-temperature wet coal gas and the coal char generate coal gas Gasification reaction, water gas shift reaction and methanation reaction to generate high temperature crude gas and furnace ash;

The reaction temperatures of the mortar gasification unit (1), the catalytic gasification unit (2) and the catalytic pyrolysis unit (3) are successively decreased.

2 . The high-efficiency catalytic gasification system for coal according to claim 1 , further comprising a separation unit ( 4 ) and a mortar preparation unit ( 5 ), the separation unit ( 4 ) being used for the catalytic pyrolysis The crude gas, tar and coal ash generated by the unit (3) are separated; the mortar preparation unit (5) is used to separate the coal ash separated by the separation unit (4) and the coal ash generated by the catalytic gasification unit (2). The furnace ash is prepared as a mortar, and the prepared mortar is passed into the mortar gasification unit (1).

3. The high-efficiency catalytic gasification system for coal according to claim 2, characterized in that it further comprises a catalyst recovery unit (6), the catalyst recovery unit (6) being used to generate electricity from the catalytic gasification unit (2) The furnace ash and the catalyst in the coal ash generated by the catalytic pyrolysis unit (3) are recovered, and the furnace ash and coal ash recovered by the catalyst are passed into the mortar preparation unit (5).

The high-efficiency catalytic gasification system for coal according to claim 2, wherein a gas-solid separation unit (7) is arranged between the catalytic pyrolysis unit (3) and the separation unit (4), so The inlet of the gas-solid separation unit (7) is connected to the catalytic pyrolysis unit (3), the gas outlet of the gas-solid separation unit (7) is connected to the separation unit (4), and the gas-solid separation unit The dust outlet of (7) is connected to the catalytic gasification unit (2).

The high-efficiency catalytic gasification system for coal according to claim 1, wherein a waste heat boiler unit (8) is arranged between the catalytic gasification unit (2) and the catalytic pyrolysis unit (3), The waste heat boiler unit (8) is used for heat exchange and cooling of the high-temperature crude gas passed from the catalytic gasification unit (2) into the catalytic pyrolysis unit (3).

6 . The high-efficiency catalytic gasification system for coal according to claim 1 , wherein the reaction temperature of the slurry gasification unit ( 1 ) is 850 to 1300° C. 7 .

7 . The high-efficiency catalytic gasification system for coal according to claim 1 , wherein the reaction temperature of the catalytic gasification unit ( 2 ) is 650 to 800° C. 8 .

8 . The high-efficiency catalytic gasification system for coal according to claim 1 , wherein the reaction temperature of the catalytic pyrolysis unit ( 3 ) is 400 to 600° C. 9 .

9. A method for efficient catalytic gasification of coal, characterized in that, comprising the steps:

In step 1, the raw coal and the high-temperature crude gas generated by the catalytic gasification unit (2) are fed into the catalytic pyrolysis unit (3), and the raw coal and the high-temperature crude gas undergo a pyrolysis reaction to generate char, crude gas, tar and coal ash , wherein the char is passed into the catalytic gasification unit (2), and the coal ash is passed into the mortar gasification unit (1);

In step 2, oxygen and water are introduced into the mortar gasification unit (1), and oxygen, water, furnace ash and coal ash undergo combustion reaction, coal gasification reaction and water-gas shift reaction to generate high-temperature wet gas and ash, and high-temperature wet gas is introduced a catalytic gasification unit (2);

In step 3, the high temperature wet coal gas and char in the catalytic gasification unit (2) undergo coal gasification reaction, water gas shift reaction and methanation reaction to generate high temperature crude gas and furnace ash, wherein the furnace ash is passed into the ash slurry gasification in step 2 In the unit (1), the high-temperature crude gas is passed into the catalytic pyrolysis unit (3) in the first step.

10 . The high-efficiency catalytic gasification method according to claim 9 , wherein the char, crude gas, tar and coal ash generated by the catalytic pyrolysis unit (3) are first passed into the gas-solid separation unit (7) for gas-solid separation. 11 . Solid separation, and then pass into the separation unit (4);

The separation unit (4) separates carbon monoxide, hydrogen and methane in the crude gas generated by the catalytic pyrolysis unit (3) as a gas product, separates the generated tar as a tar product, and separates the coal ash into the catalyst recovery unit (6) ;

The furnace ash generated by the catalytic gasification unit (2) and the coal ash separated by the separation unit (4) are first passed into the catalyst recovery unit (6) for catalyst recovery, and then passed into the mortar preparation unit (5), and the prepared mortar is passed into the mortar gasification unit (1);

The high-temperature crude gas generated by the catalytic gasification unit (2) is first passed into the waste heat boiler unit (8) for heat exchange and cooling, and then passed into the catalytic pyrolysis unit (3).