Coal catalytic gasification method and system

文档序号：1668038 发布日期：2019-12-31 浏览：27次中文

阅读说明：本技术 一种煤催化气化方法及系统 (Coal catalytic gasification method and system ) 是由李克忠祖静茹于 2019-08-30 设计创作，主要内容包括：本发明涉及一种煤催化气化方法及系统,方法包括：步骤一：将煤颗粒、水蒸气以及负载有催化剂的热活性半焦在流化床气化反应器中发生催化气化反应,生成富含甲烷的产品气及固体颗粒,固体颗粒包括活性半焦颗粒、飞灰、残碳颗粒和灰渣；步骤二：分离产品气及其携带的固体颗粒,得到活性半焦颗粒、残碳颗粒和灰渣；步骤三：在转化炉内热态下对活性半焦颗粒进行催化剂负载、活化,并将负载有催化剂的热活性半焦送入流化床气化反应器中参与催化气化反应。该方法解决了由于原煤物料的粒径分级带来的原料利用率低的问题,并有针对性将催化剂进行有效负载,提高了原煤物料及催化剂的利用效率。同时,提高气化工段的效率,使得技术的经济性得到有效提升。(The invention relates to a coal catalytic gasification method and a system, wherein the method comprises the following steps: the method comprises the following steps: carrying out catalytic gasification reaction on coal particles, steam and catalyst-loaded thermal active semicoke in a fluidized bed gasification reactor to generate product gas rich in methane and solid particles, wherein the solid particles comprise active semicoke particles, fly ash, carbon residue particles and ash; step two: separating the product gas and solid particles carried by the product gas to obtain active semicoke particles, carbon residue particles and ash; step three: and carrying out catalyst loading and activation on the active semicoke particles in a converter under a thermal state, and sending the thermal active semicoke loaded with the catalyst into a fluidized bed gasification reactor to participate in catalytic gasification reaction. The method solves the problem of low raw material utilization rate caused by particle size classification of raw coal materials, and carries out effective loading on the catalyst in a targeted manner, thereby improving the utilization efficiency of the raw coal materials and the catalyst. Meanwhile, the efficiency of the gasification section is improved, and the economical efficiency of the technology is effectively improved.)

1. A method of catalytic coal gasification, comprising:

the method comprises the following steps: carrying out catalytic gasification reaction on coal particles, steam and catalyst-loaded hot active semicoke in a fluidized bed gasification reactor to generate a product gas rich in methane and solid particles, wherein the solid particles comprise active semicoke particles, fly ash, carbon residue particles and ash residues;

step two: separating the product gas and solid particles carried by the product gas to obtain the active semicoke particles, carbon residue particles and ash;

step three: and carrying out catalyst loading and activation on the active semicoke particles in a converter under a thermal state, and feeding the catalyst-loaded thermal active semicoke into the fluidized bed gasification reactor to participate in the catalytic gasification reaction.

2. The catalytic coal gasification process of claim 1, wherein in the third step, air and steam are supplied into the converter as fluidizing gas to fluidize the solid particles in the converter and simultaneously burn the carbon residue particles in the solid particles.

3. The catalytic coal gasification process according to claim 1 or 2, wherein the active semicoke particles, carbon residue particles and ash obtained by separation in the second step are dry-mixed with a catalyst in a catalyst loading system to be uniform before the third step.

4. The catalytic coal gasification process of claim 1, wherein the temperature in the fluidized-bed gasification reactor is 600-800 ℃ and the pressure is 0.5-4 MPa.

5. The catalytic coal gasification method according to claim 1 or 4, wherein the mass ratio of the steam to the coal particles entering the fluidized bed gasification reactor is 0.6:1 to 1.5: 1.

6. The catalytic coal gasification process of claim 1, wherein the temperature in the reformer is 850-.

7. The catalytic coal gasification method according to claim 2, wherein the mass ratio of air and steam entering the reformer is 15:1 to 10:1,

and the mass ratio of the air entering the reformer to the coal entering the reactor is 1: 2-2: 1.

8. the catalytic coal gasification process of claim 1, wherein the particle size of the coal particles entering the fluidized bed gasification reactor is between 0.1mm and 1 mm;

wherein, when the mass of the coal particles with the particle size of less than 0.18mm accounts for less than 10 percent of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst added into the converter is 5 to 10 percent of the total mass of the coal particles thrown into the fluidized bed gasification reactor;

when the mass of the coal particles with the particle size of less than 0.18mm accounts for 10-30% of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst added into the converter is 10-15% of the total mass of the coal particles fed into the fluidized bed gasification reactor;

when the mass of the coal particles with the particle size of less than 0.18mm in the coal particles accounts for more than 30% of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst added into the converter is 15% -20% of the total mass of the coal particles fed into the fluidized bed gasification reactor.

9. A catalytic coal gasification system with which the catalytic coal gasification method of any one of claims 1 to 8 is performed, comprising:

the gasification device comprises a fluidized bed gasification reactor, a gas distributor is arranged in the fluidized bed gasification reactor and close to the bottom of the fluidized bed gasification reactor, a steam inlet, a coal particle inlet and a material returning port are arranged on the outer wall of the fluidized bed gasification reactor, the steam inlet is positioned below the gas distributor, the coal particle inlet and the material returning port are positioned above the gas distributor, and a material outlet is arranged at the top of the reactor;

the gas-solid separation equipment is provided with an inlet, a gas phase outlet and a solid phase outlet, and is communicated with the material outlet of the fluidized bed gasification reactor through the inlet;

the bottom of the converter is provided with a slag discharge port and a fluidizing gas inlet, the middle lower part of the converter is provided with a feed port, the middle part of the converter is provided with an overflow port, and the top of the converter is provided with a flue gas outlet.

10. The catalytic coal gasification system of claim 9, wherein a catalyst loading system is connected between the solid phase outlet of the gas-solid separation device and the feed inlet of the reformer.

Technical Field

The invention relates to the technical field of catalytic coal gasification, in particular to a catalytic coal gasification method and system.

Background

Currently, catalytic coal gasification is an advanced gasification method, coal is mixed with alkali metal and alkaline earth metal, and then gasification reaction occurs at about 700 ℃, and because of the addition of the catalyst, the gasification reaction can be accelerated, so that the coal can reach higher conversion efficiency at a lower temperature. The effective degree of catalyst loading directly determines the catalytic gasification effect of coal particles, the traditional catalytic gasification usually adopts a wet loading process to load the catalyst on the surface of the coal particles, and then the coal particles enter a gasification furnace to carry out a series of catalytic gasification reactions, and because most of the catalyst in the wet loading still keeps a state of physical combination with the coal, the catalytic effect of the catalyst cannot be effectively exerted, so that the utilization efficiency of the catalyst and the gasification efficiency of the coal are reduced.

Meanwhile, in a large gasification device, the distribution of coal particles used as reaction raw materials is wide, and the large coal particles have the problems of high surface catalyst loading rate and low loading rate in pore channels, so that the carbon conversion rate in the large coal particles is low, and a large amount of unreacted carbon is discharged out of the furnace along with ash. Small coal particles are not sufficiently retained in the reaction zone due to the low specific gravity and are carried out of the gasifier with the gasification product raw gas, thereby causing the loss of raw material carbon. Meanwhile, the distribution characteristics of coal particles and catalysts restrict the efficient and clean development of catalytic gasification.

Disclosure of Invention

In view of the above, the present invention provides a coal catalytic gasification method and system capable of improving utilization efficiency of raw coal materials and catalysts and greatly reducing catalytic gasification cost of raw coal, so as to solve the problems in the prior art.

According to a first aspect of the present invention, there is provided a catalytic coal gasification process comprising:

step two: separating the product gas and solid particles carried by the product gas to obtain the active semicoke particles, carbon residue particles and ash;

Preferably, in the third step, air and water vapor are supplied into the converter as fluidizing gas, so that the solid particles in the converter are fluidized and simultaneously the carbon residue particles in the solid particles are combusted.

Preferably, before the third step, the active semicoke particles, carbon residue particles and ash obtained by separation in the second step are mixed with the catalyst in a catalyst loading system by a dry method to be uniform.

Preferably, the temperature in the fluidized bed gasification reactor is 600-800 ℃, and the pressure is 0.5-4 MPa.

Preferably, the mass ratio of steam to coal particles entering the fluidized bed gasification reactor is 0.6: 1-1.5: 1.

Preferably, the temperature in the converter is 850-.

Preferably, the mass ratio of the air and the water vapor entering the reformer is 15: 1-10: 1,

and the mass ratio of the air entering the reformer to the coal entering the reactor is 1: 2-2: 1.

preferably, the particle size of the coal particles entering the fluidized bed gasification reactor is between 0.1mm and 1 mm;

According to a second aspect of the present invention, there is provided a catalytic coal gasification system with which the catalytic coal gasification method is performed, the catalytic coal gasification system comprising:

Preferably, a catalyst loading system is connected between the solid phase outlet of the gas-solid separation equipment and the feed inlet of the converter.

Has the advantages that:

the coal catalytic gasification method and the coal catalytic gasification system solve the problem of low raw material utilization rate caused by particle size grading of raw coal materials, and can effectively utilize raw coals with different particle sizes; meanwhile, the catalyst is loaded effectively in a targeted manner, so that the utilization efficiency of the raw coal material and the catalyst is improved. Moreover, the efficiency of the gasification section is improved by fully recycling energy and materials, so that the economical efficiency of the technology is effectively improved.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 shows a flow diagram of the steps of a method for catalytic gasification of coal according to an embodiment of the invention.

FIG. 2 shows a schematic diagram of a catalytic coal gasification system according to an embodiment of the invention.

In the figure: the device comprises a fluidized bed gasification reactor 1, a gas distributor 11, a steam inlet 12, a coal particle inlet 13, a material return port 14, a material outlet 15, a converter 2, a slag discharge port 21, a fluidized gas inlet 22, a feed inlet 23, an overflow port 24, a flue gas outlet 25, a feed system 3, a gas-solid separation device 4, an inlet 41, a gas phase outlet 42, a solid phase outlet 43, a catalyst loading system 5, a purification synthesis system 6 and a thermoelectric system 7.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

FIG. 2 shows a schematic diagram of a catalytic coal gasification system according to an embodiment of the invention. As shown in fig. 2, the present invention provides a catalytic coal gasification system comprising a fluidized bed gasification reactor, a gas-solid separation apparatus, and a reformer 2.

A gas distributor 11 is arranged in the fluidized bed gasification reactor close to the bottom, and a steam inlet 12, a coal particle inlet 13 and a material returning port 14 are arranged on the outer wall of the fluidized bed gasification reactor. The steam inlet 12 is located below the gas distributor 11, the coal particle inlet 13 and the material return port 14 are located above the gas distributor 11, and the top of the reactor is provided with a material outlet 15.

The gas-solid separation device is provided with an inlet 41, a gas phase outlet 42 and a solid phase outlet 43, and the gas-solid separation device is communicated with the material outlet 15 of the fluidized bed gasification reactor through the inlet 41.

The bottom of the converter 2 is provided with a slag discharge port 21 and a fluidized gas inlet 22, the middle lower part of the converter is provided with a feed port 23, the middle part of the converter is provided with an overflow port 24, and the top of the converter is provided with a flue gas outlet 25, the converter 2 is communicated with a solid phase outlet 43 of the gas-solid separation equipment through the feed port 23, and is communicated with a return port 14 of the fluidized bed gasification reactor through the overflow port 24.

Further, a catalyst loading system 5 is connected between the solid phase outlet 43 of the gas-solid separation device and the feed inlet 23 of the reformer 2.

Wherein, the coal particle inlet 13 of the fluidized bed gasification reactor is communicated with the feeding system 3, the feeding system 3 is used for providing coal particles used as reaction raw materials for the fluidized bed gasification reactor, the gas phase outlet 42 of the gas-solid separation equipment is communicated with the purification synthesis system 6, and the purification synthesis system 6 filters the gas from the gas-solid separation equipment and synthesizes methane gas. The flue gas outlet 25 of the reformer 2 is in communication with the thermoelectric system 7, and the thermoelectric system 7 generates electricity using the hot flue gas from the reformer 2.

FIG. 1 shows a flow diagram of the steps of a method for catalytic gasification of coal according to an embodiment of the invention. As shown in fig. 1, the present invention provides a catalytic coal gasification method, comprising:

in this step, the coal particles enter the fluidized bed gasification reactor from the coal particle inlet 13 of the fluidized bed gasification reactor. The coal particles and the catalyst-loaded thermally active semi-coke particles are pyrolyzed and gasified in the fluidized bed gasification reactor, and the coal particles and the catalyst-loaded thermally active semi-coke particles stay in the fluidized bed gasification reactor for different time periods due to different particle sizes and are converted into different solid particles, wherein the solid particles comprise the active semi-coke particles, fly ash, carbon residue particles and ash slag, and meanwhile, product gas rich in methane is generated.

Specifically, steam is introduced from a steam inlet 12 of the fluidized bed gasification reactor, small-particle raw coal in coal particles is pyrolyzed and gasified under the action of coarse coal and the steam in the fluidized bed gasification reaction, is converted into active semicoke, and quickly flows out of the fluidized bed gasification reactor. The part of active semicoke has the highest specific surface area in all materials in the invention, namely, has high adsorption capacity.

The method comprises the steps that large-particle raw coal in coal particles stays in a fluidized bed gasification reactor for a long time, pyrolysis, gasification and methanation reactions are carried out in the fluidized bed gasification reactor, a product gas rich in methane is generated, the product gas comprises water vapor, carbon monoxide, hydrogen and methane, residual carbon and ash slag are generated, and gases such as the carbon monoxide, the hydrogen and the methane in the product gas form raw coal gas. Specifically, under the action of the steam, the surface area of the large-particle raw coal is gradually increased, so that the capability of capturing the catalyst by the large-particle raw coal is gradually enhanced, the large-particle raw coal is captured and collected and then subjected to gasification and methanation reactions, the reactions of the large-particle raw coal surface gasification and methanation series are violent and strongly exothermic, and in the process, the endothermic reaction of the carbohydrate gasification and the exothermic reaction of the methanation in the fluidized bed gasification reactor can be well coupled in balance, so that the matching of heat and reaction in the fluidized bed gasification reactor is met. And after the consumption of the carbonaceous raw materials on the surface of the large-particle raw coal is finished, generating carbon residue particles, wherein the main component of the carbon residue particles is stubborn residue carbon, and meanwhile, because the retention time in the fluidized bed gasification reactor is long, the large-particle raw coal after gasification treatment, namely the ash component on the carbon residue, is gradually exposed, and active substances in the ash component on the carbon residue are combined with partial catalyst in the fluidized bed gasification reactor under the reducing atmosphere to form ash slag crystals with compact structures. The dense structure of the ash crystals makes the specific gravity of the ash crystals larger, so that the ash crystals formed by large-particle raw coal with the same volume have larger specific gravity than active semicoke generated by small-particle materials.

The catalyst-loaded thermally active semicoke is pyrolyzed and gasified under the action of water vapor and crude gas in a fluidized bed gasification reactor, and is converted into fly ash or ash. The particle size of the fly ash is smaller than that of other solid particles, such as carbon residue particles and semi-coke particles, so that the fly ash is not easy to stay in the fluidized bed gasification reactor and is easy to flow out of the fluidized bed gasification reactor.

Step two: separating the product gas and solid particles carried by the product gas to obtain the active semicoke particles, carbon residue particles and ash;

in the step, the gas-solid separation equipment pumps the product gas generated in the step I out of a material outlet 15 of the fluidized bed gasification reactor, and in the pumping-out process, solid particles are fluidized out of the material outlet 15 under the product gas and enter the gas-solid separation equipment. The gas-solid separation equipment is used for carrying out primary gas-solid separation on the product gas and solid particles carried by the product gas, wherein solid phase components including active semi-coke particles, carbon residue particles and ash are separated and enter the step three, separated gas phase components including carbon monoxide, hydrogen and fly ash enter the purification synthesis system 6, secondary gas-solid separation is carried out in the purification synthesis system 6, the fly ash is purified and collected, and the rest carbon monoxide and hydrogen components are discharged and collected by synthetic methane.

Step three: and carrying out catalyst loading and activation on the active semicoke particles in a thermal state in the converter 2, and feeding the catalyst-loaded hot active semicoke into the fluidized bed gasification reactor to participate in the catalytic gasification reaction.

In this step, fluidizing gas is introduced from the fluidizing gas inlet 22 of the converter 2 to fluidize the material in the converter 2. And the separated active semi-coke particles, residual carbon particles and ash slag enter the converter 2 from a feed inlet 23 of the converter 2, ash slag components in the ash slag components continuously compact in the circulating process and finally fall to the bottom of the converter for discharging, the active semi-coke particles and the residual carbon particles are loaded with a catalyst in a thermal environment, and the catalyst is activated in the thermal environment and is combined with the active semi-coke to generate the catalyst-loaded thermally active semi-coke particles. The specific gravity of the catalyst-loaded thermally active semi-coke particles is smaller than that of the catalyst-loaded carbon residue particles, so that the catalyst-loaded thermally active semi-coke particles and the catalyst-loaded carbon residue particles can be fluidized and separated in a layered manner. The catalyst-loaded thermal activity semicoke is fluidized to a fluidized bed gasification reactor to participate in catalytic gasification reaction, so that non-oxidation is realized more efficiently, the carbon utilization rate is high, the gas production rate is high, the catalyst enters the pores of the coke, the loading effect is good, and the catalytic effect is good. In addition, the residual carbon particles are enriched at the bottom of the reformer 2 to be combusted and released, so that a thermal state environment is provided for the reformer 2, and the generated heat can be recycled in the whole coal catalytic gasification system to provide a heat source for the whole system.

Since there is no oxygen in the fluidized bed gasification reactor, all of the catalyst is used to promote catalytic gasification and catalytic methanation reactions. In this embodiment, the gasifying agent in the fluidized bed gasification reactor only contains steam and no oxygen, so that the degree of gasification reaction is greatly improved, and the existence of oxygen components of combustible gas enables carbon monoxide and hydrogen generated by gasification to be subjected to methanation reaction under the action of a catalyst (oxygen in a conventional gasification furnace can preferentially react with the generated carbon monoxide and hydrogen), so that more methane products are generated, and the utilization efficiency of carbon is improved.

The coal catalytic gasification method solves the problem of low raw material utilization rate caused by particle size grading of raw coal materials, and can effectively utilize raw coal with different particle sizes; meanwhile, the catalyst is loaded effectively in a targeted manner, so that the utilization efficiency of the raw coal material and the catalyst is improved. Moreover, the efficiency of the gasification section is improved by fully recycling energy and materials, so that the economical efficiency of the technology is effectively improved.

In the third step, air and water vapor are supplied into the reformer 2 as fluidizing gas, so that the solid particles in the reformer 2 are fluidized while the carbon residue particles in the solid particles are combusted. Through providing air and vapor as fluidization gas in to converter 2, can make the material fluidization in converter 2 on the one hand, the high efficiency of the reaction of being convenient for goes on, on the other hand, can make the thermal activity semicoke granule that has the catalyst of load carry out fluidization layering separation with the carbon residue granule of load catalyst, make carbon residue granule burn at the lower floor, provide the heat for the active semicoke of upper strata load catalyst, the hot flue gas that the burning produced can be put to thermoelectric system 7 from the flue gas outlet 25 of converter 2 outward and generate electricity, thereby economic nature has been improved.

Further, before the third step, the active semicoke particles, carbon residue particles and ash residues obtained by separation in the second step are uniformly mixed with the catalyst in the catalyst loading system 5 by a dry method. Specifically, the particles, carbon residue particles and ash separated from the solid phase outlet 43 of the gas-solid separation device enter the catalyst loading system 5, and are dry-mixed with the catalyst in a dry state to form a mixed material, the active carbocoal particles and the carbon residue particles in the mixed material are dry-mixed with the catalyst respectively, and the mixed material enters the conversion furnace 2 from the feed inlet 23 of the conversion furnace 2. After entering the third step, the active semicoke particles are activated in a thermal state environment in the converter 2 to generate the catalyst-loaded thermal active semicoke. In the method, the catalyst can be selected from alkali metal, alkaline earth metal or a mixture of several alkali metals and alkaline earth metals, and is further preferably a catalyst with better migration capability at a certain temperature, such as potassium carbonate, sodium carbonate and the like.

The step provides a basis for activating the active semicoke loaded with the catalyst in the step three, so that various materials are fully mixed and contacted, the combination on the physical state is realized, and favorable conditions are created for the loading activation of the catalyst in the converter 2 in the step three.

Further, the temperature in the fluidized bed gasification reactor is 600-800 ℃, and the pressure is 0.5-4 MPa. Under the conditions of the temperature and the pressure, the full progress of the catalytic gasification reaction in the fluidized bed gasification reactor is facilitated.

Further, the mass ratio of the steam entering the fluidized bed gasification reactor to the coal particles is 0.6: 1-1.5: 1. Thus, sufficient steam can be provided for gasification reaction in the fluidized bed gasification reactor, and the heat of the reactor can not be excessively consumed.

Further, the temperature in the conversion furnace 2 is 850-1000 ℃, and the pressure is 0.5-4 MPa. Therefore, the thermally active semicoke loaded with the catalyst is convenient to overflow into the fluidized bed gasification reactor along with heat.

Further, the mass ratio of the air entering the reformer 2 to the steam is 15: 1-10: 1, and the mass ratio of the air entering the reformer 2 to the coal entering the reactor is 1: 2-2: 1. Therefore, on one hand, proper fluidization strength in the converter 2 is ensured, so that the material can be fully fluidized, and the separation of the active semicoke particles loaded with the catalyst and the residual carbon particles is facilitated; on the other hand, it is ensured that the residual carbon particles are burned off, while the catalyst-loaded thermally active semicoke particles are not or in small amounts burned or gasified.

Further, the particle size of the coal particles entering the fluidized bed gasification reactor is between 0.1mm and 1 mm. Wherein, when the mass of the coal particles with the particle size of less than 0.18mm accounts for less than 10% of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst is 5-10% of the total mass of the coal particles fed into the fluidized bed gasification reactor; when the mass of the coal particles with the particle size of less than 0.18mm accounts for 10-30% of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst accounts for 10-15% of the total mass of the coal particles fed into the fluidized bed gasification reactor; when the mass of the coal particles with the particle size of less than 0.18mm accounts for more than 30% of the total mass of the coal particles entering the fluidized bed gasification reactor, the mass of the catalyst accounts for 15% -20% of the total mass of the coal particles fed into the fluidized bed gasification reactor.

In this way, the particle size of the coal particles entering the fluidized-bed gasification reactor is defined in order to secure the fluidization effect of the materials in the reactor and the reformer 2. When the amount of small particles is large, the amount of the carried-out active semicoke which needs to be loaded with the catalyst is relatively large, so that the catalyst proportion is large.

The process for catalytic coal gasification according to the present application will be further described with reference to several specific embodiments.

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