A method for the comprehensive utilization of coal gasification ash and solid waste through a tiered and graded process.

Abstract

This invention relates to the field of comprehensive utilization technology of coal gasification ash residue, and discloses a method for the graded and comprehensive utilization of solid waste from coal gasification ash residue, comprising the following steps: separating the ash residue into coarse ash residue and fine ash residue; physically sorting the fine ash residue to obtain a fine ash filter cake with a carbon content of 5% to 70%, a first low-carbon ash residue with a carbon content ≤5%, and a carbon-rich ash residue with a carbon content ≥70%; using fine ash filter cake to form a second low-carbon ash residue using fine ash residue decarbonization technology; adding a binder to the carbon-rich ash residue and gasifying it to obtain a third low-carbon ash residue and... Coal gasification ash slag; high-alumina ash slag with Al2O3 ≥ 20% in low-carbon ash slag is used to prepare polyaluminum chloride, etc.; high-silica ash slag with SiO2 ≥ 40% is used to prepare water glass; low-silica alumina ash slag with SiO2 < 40% and Al2O3 < 20% is used with coal gangue or fly ash to prepare coal-based solid waste cementitious materials or coal-based solid waste filling materials. The ash slag utilization method is simple and has a high comprehensive utilization rate. It can not only dispose of coal gasification ash slag on a large scale and protect the ecological environment, but also make full use of the value of coal gasification ash slag.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of coal gasification ash residue, and in particular to a method for the graded and comprehensive utilization of solid waste from coal gasification ash residue. Background Technology

[0002] Coal gasification technology refers to the process by which coal interacts with a gasifying agent to undergo a series of chemical reactions, converting coal into syngas. Due to its advantages of maximizing resource utilization and minimizing pollutant emissions, it is a crucial sector of modern coal chemical technology. However, the coal gasification process generates a large amount of coal gasification ash. The massive discharge of ash not only occupies vast amounts of land but also causes soil and water pollution, severely impacting the environment. Therefore, the resource utilization of coal gasification ash is an urgent requirement for high-quality ecological and environmental development.

[0003] In the field of coal gasification technology, the fly ash obtained from the cyclone separator and the filter cake obtained from the washing system during the coal gasification process are often classified as fine slag, while the large-particle ash obtained from the slag discharge hopper during the coal gasification process are classified as coarse slag.

[0004] Currently, the applications of coal gasification ash residue both domestically and internationally mainly focus on the following aspects: ① Building materials: cementitious materials, aggregates, concrete, wall materials, and non-fired bricks, etc.; ② Soil and water remediation: soil improvement, use as adsorbent materials for water remediation, etc.; ③ Utilization of residual carbon: residual carbon properties, recycling and co-firing, residual carbon upgrading, etc.; ④ Preparation of high-value-added materials: rubber and plastic fillers, catalyst carriers, silicon-based materials, ceramic materials, etc. However, the amount of coal gasification ash residue generated remains high, while the comprehensive utilization rate of resources is low. This indicates that although some technologies and projects are attempting to improve the utilization rate of coal gasification ash residue, there is still significant room for improvement overall, which seriously restricts the development of the modern coal chemical industry. Summary of the Invention

[0005] This invention proposes a method for the comprehensive utilization of coal gasification ash solid waste through a tiered and graded approach to address the shortcomings of the prior art. This method improves the utilization value of coal gasification ash solid waste, reduces its environmental impact, enables large-scale disposal of coal gasification ash, protects the ecological environment, and fully utilizes the value of coal gasification ash.

[0006] The technical solution of this invention is: a method for the comprehensive utilization of coal gasification ash residue solid waste through a tiered and graded process, comprising:

[0007] S1: The coal gasification ash is divided into coarse ash and fine ash; the fine ash is the fly ash obtained by the cyclone separator and the filter cake obtained by the washing system during the coal gasification process, and the coarse ash is the large-particle ash obtained by the ash discharge lock hopper during the coal gasification process.

[0008] S2: The fine slag is physically sorted to obtain fine slag filter cake with a carbon content of 5% to 70%, first low carbon ash slag with a carbon content of ≤5%, and carbon-rich ash slag with a carbon content of ≥70%.

[0009] S3. The fine slag filter cake is decarbonized using fine slag decarburization technology to form a second low-carbon ash slag with a carbon content of ≤5%; the carbon-rich ash slag is mixed with a binder to form a carbon-rich slag, which is then re-gasified and reused using gasification technology to obtain a third low-carbon ash slag and coal gas with a carbon content of ≤5%.

[0010] S4. Use the high-alumina ash slag with Al2O3 ≥ 20% in the first, second, and third low-carbon ash slags to prepare polyaluminum chloride, alumina, or aluminum hydroxide; use the high-silicon ash slag with SiO2 ≥ 40% to prepare water glass, silicon carbide, or rubber filler; use the low-silicon aluminum ash slag with SiO2 < 40% and Al2O3 < 20% with coal gangue or fly ash to prepare coal-based solid waste cementitious materials or coal-based solid waste filling materials.

[0011] In at least one embodiment of the present invention, in step S2, the physical sorting method uses a spiral separator, a screening machine or a flotation machine to separate carbon ash from coal gasification ash residue.

[0012] In at least one embodiment of the present invention, in step S3, the fine slag decarbonization technology refers to preheating decarbonization technology or pyrometallurgical combustion decarbonization, which utilizes the residual carbon in the fine slag to undergo rapid oxidation reaction, so that the fine slag filter cake is transformed into a second low-carbon ash slag.

[0013] In at least one embodiment of the present invention, in step S3, the carbon-rich ash slag can also be combined with coal for reuse.

[0014] In at least one embodiment of the present invention, in step S4, the distinction between high-alumina ash slag, high-silica ash slag and low-silica-alumina ash slag is made by using an X-ray fluorescence spectrometer to test the Al2O3 and SiO2 content in the first low-carbon ash slag, the second low-carbon ash slag and the third low-carbon ash slag, thereby distinguishing the types of the first low-carbon ash slag, the second low-carbon ash slag and the third low-carbon ash slag.

[0015] In at least one embodiment of the present invention, in step S4, the coarse slag separated in step S1 is directly tested using an X-ray fluorescence spectrometer to determine the type of coarse slag among high-alumina ash slag, high-silica ash slag, and low-silica-alumina ash slag.

[0016] In at least one embodiment of the present invention, in step S4, the coal-based solid waste cementing material refers to a material made from byproducts of coal mining, processing, combustion and conversion processes that can bind other materials.

[0017] In at least one embodiment of the present invention, in step S4, the coal-based solid waste backfill material refers to a material with a certain strength prepared by mines to treat solid waste or to control surface subsidence and rock strata movement when mining coal resources under buildings, water bodies, or roads.

[0018] In at least one embodiment of the present invention, the fine slag is fly ash obtained from the cyclone separator and filter cake obtained from the washing system during the coal gasification process, and the coarse slag is large-particle ash obtained from the slag discharge hopper during the coal gasification process, which belongs to low-carbon ash.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The method for comprehensive utilization of coal gasification ash in a graded manner proposed in this invention can extract and recover a large amount of valuable elements such as silicon and aluminum contained in coal gasification ash, and convert them into chemical raw materials such as aluminum chloride, alumina, aluminum hydroxide, water glass, silicon carbide or rubber filler, as well as building materials such as coal-based solid waste cementitious materials or coal-based solid waste filling materials. The conversion of these high-value-added products improves resource utilization efficiency, reduces resource waste, promotes the development of circular economy, and realizes efficient utilization and recycling of resources.

[0021] 2. This invention can promote the reduction, resource utilization, high-value utilization and green disposal of coal gasification ash residue, innovate the industrial model of resource utilization and green and efficient backfilling disposal of coal gasification ash residue, and effectively support the coordinated efficiency improvement and green development of pollution reduction and carbon reduction in the coal chemical industry. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the process of differentiating and utilizing components according to the present invention. Detailed Implementation

[0023] The accompanying drawings in this invention are not strictly drawn to scale, and the specific dimensions and quantity of each structure can be determined according to actual needs. The drawings described in this invention are merely structural schematic diagrams.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "inner," "outer," "upper," "lower," "far," "near," "front," and "rear" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0026] Currently, the applications of coal gasification ash residue both domestically and internationally mainly focus on the following aspects: ① Building materials: cementitious materials, aggregates, concrete, wall materials, and non-fired bricks, etc.; ② Soil and water remediation: soil improvement, use as adsorbent materials for water remediation, etc.; ③ Utilization of residual carbon: residual carbon properties, recycling and co-firing, residual carbon upgrading, etc.; ④ Preparation of high-value-added materials: rubber and plastic fillers, catalyst carriers, silicon-based materials, ceramic materials, etc. The production of coal gasification ash residue remains consistently high, but the comprehensive utilization rate of resources is only 31.6%. This indicates that although some technologies and projects are attempting to improve the utilization rate of coal gasification ash residue, there is still significant room for improvement overall, severely restricting the development of the modern coal chemical industry.

[0027] This invention addresses the problems of low comprehensive utilization rate and difficulty in large-scale disposal of coal gasification ash residue. It proposes a graded and tiered comprehensive utilization method for coal gasification ash residue, which fully considers the physical characteristics (particle size), chemical composition (content of oxides such as aluminum and silicon, and carbon content) of the residue. This method achieves graded and tiered comprehensive utilization of the ash residue, improving its utilization value while reducing its environmental impact. It enables large-scale disposal of coal gasification ash residue, protects the ecological environment, and fully utilizes its value.

[0028] Combination Figure 1 As shown, a method for the comprehensive utilization of coal gasification ash solid waste through a tiered and graded process includes:

[0029] S1: Coal gasification ash is divided into coarse ash and fine ash; fine ash is the fly ash obtained from the cyclone separator and the filter cake obtained from the washing system during the coal gasification process, while coarse ash is the large-particle ash obtained from the ash discharge hopper during the coal gasification process; the definition and distinction between coarse ash and fine ash are based on the different ways they are obtained during the coal gasification process, which belongs to the basic knowledge of this discipline.

[0030] S2: The fine slag is physically sorted to obtain fine slag filter cake with a carbon content of 5% to 70%, first low carbon ash slag with a carbon content of ≤5%, and carbon-rich ash slag with a carbon content of ≥70%.

[0031] S3. The fine slag filter cake is decarbonized using fine slag decarburization technology to form a second low-carbon ash slag with a carbon content of ≤5%; the carbon-rich ash slag is mixed with a binder to form a carbon-rich slag, which is then re-gasified and reused using gasification technology to obtain a third low-carbon ash slag and coal gas with a carbon content of ≤5%.

[0032] S4. High-alumina ash slag with Al2O3 ≥ 20% from the first, second, and third low-carbon ash slags is used to prepare polyaluminum chloride, alumina, or aluminum hydroxide; high-silica ash slag with SiO2 ≥ 40% is used to prepare water glass, silicon carbide, or rubber fillers; low-silica alumina ash slag with SiO2 < 40% and Al2O3 < 20% is combined with coal gangue or fly ash to prepare coal-based solid waste cementitious materials or coal-based solid waste filling materials. This method for utilizing coal gasification ash slag is simple and has a high comprehensive utilization rate. It can not only dispose of coal gasification ash slag on a large scale and protect the ecological environment, but also fully utilize the value of coal gasification ash slag.

[0033] As an alternative embodiment, physical separation methods utilize physical separation equipment such as spiral separators, screening machines, or flotation machines to separate carbon and ash from coal gasification ash residue.

[0034] As an alternative embodiment, in step S3, the fine slag decarburization technology refers to preheating decarburization technology or pyrometallurgical combustion decarburization, which utilizes the residual carbon in the fine slag to undergo a rapid oxidation reaction, so that the fine slag filter cake is transformed into a second low-carbon ash slag.

[0035] As an alternative embodiment, in step S4, the carbon-rich slag is a gasification feedstock with high activity and large particle size formed by adding a binder to carbon-rich ash slag.

[0036] As an alternative embodiment, in step S3, the carbon-rich ash can also be combined with coal for reuse; adding a binder to the carbon-rich ash to form carbon-rich slag and gasifying it, and combining the carbon-rich ash with coal for reuse are two parallel solutions, and the specific choice can be made according to the actual needs of the plant.

[0037] As an alternative embodiment, in step S4, the distinction between high-alumina ash slag, high-silica ash slag, and low-silica-alumina ash slag is made by using an X-ray fluorescence spectrometer to test the Al2O3 and SiO2 content in the first, second, and third low-carbon ash slags, thereby distinguishing the types of the first, second, and third low-carbon ash slags.

[0038] As an alternative embodiment, in step S4, the coarse slag separated in step S1 is directly tested using an X-ray fluorescence spectrometer to determine the type of coarse slag among high-alumina slag, high-silica slag, and low-silica-alumina slag.

[0039] As an alternative embodiment, in step S4, the coal-based solid waste cementitious material refers to a composite solid material that can bind other materials to form a certain strength, similar to cement, and can be used to prepare building materials such as concrete and mortar.

[0040] As an alternative embodiment, in step S4, the coal-based solid waste backfill material refers to a material with a certain strength prepared by mines to treat solid waste or to control surface subsidence and rock strata movement when mining coal resources under buildings, water bodies, or roads.

[0041] Practical application examples of this invention:

[0042] 1. The plant emits 600,000 tons of coal gasification ash annually, including 400,000 tons of coarse ash and 200,000 tons of fine ash. The fine ash is further separated into 50,000 tons of carbon-rich ash, 50,000 tons of fine ash filter cake, and 100,000 tons of low-carbon ash by flotation.

[0043] 2. The fine slag filter cake was decarbonized using preheating decarbonization technology, achieving a carbon content of ≤5% in the decarbonized ash residue, and producing 40,000 tons of low-carbon ash residue.

[0044] 3. Adding a binder to 10,000 tons of carbon-rich ash slag forms carbon-rich slag, which, through gasification, produces 3,500 tons of low-carbon ash slag and 2,000 cubic meters of coal gas. The remaining 40,000 tons of carbon-rich ash slag are then blended with coal for reuse.

[0045] 4. 40,000 tons of fly ash, sodium carbonate, and water glass were added to the obtained 60,000 tons of low-carbon ash residue to prepare 100,000 tons of coal-based solid waste gel material.

[0046] 5. 480,000 tons of low-carbon ash slag with low aluminum and silicon content (SiO2 < 40%, Al2O3 < 20%) were mixed with 1.1 million tons of coal gangue, 32 tons of water, and 100,000 tons of coal-based solid waste gel material from a coal mine to obtain 2 million tons of coal-based solid waste backfill material. This material was then completely filled into the mining space generated by the mine, replacing 1.3 million tons of coal resources under the buildings and structures, controlling surface subsidence, and protecting the surface ecological environment.

[0047] The above embodiments are merely specific implementations of this invention patent, used to illustrate the technical solutions of this invention patent, and not to limit it. The protection scope of this invention patent is not limited thereto. Although this invention patent has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in this invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions implemented by this invention patent, and should all be covered within the protection scope of this invention.

Claims

1. A method for the comprehensive utilization of coal gasification ash residue solid waste through a tiered and graded process, characterized in that, Includes the following steps: S1: Separate coal gasification ash into coarse ash and fine ash; S2: The fine slag is physically sorted to obtain fine slag filter cake with a carbon content of 5% to 70%, first low carbon ash slag with a carbon content of <5%, and carbon-rich ash slag with a carbon content of >70%. S3. The fine slag filter cake is decarbonized using fine slag decarburization technology to form a second low-carbon ash slag with a carbon content of <5%; the carbon-rich ash slag is mixed with a binder to form a carbon-rich slag, which is then re-gasified and reused using gasification technology to obtain a third low-carbon ash slag and coal gas with a carbon content of <5%. S4. Use the high-alumina ash slag with Al2O3 ≥ 20% in the first, second, and third low-carbon ash slags to prepare polyaluminum chloride, alumina, or aluminum hydroxide; use the high-silicon ash slag with SiO2 ≥ 40% to prepare water glass, silicon carbide, or rubber filler; use the low-silicon aluminum ash slag with SiO2 < 40% and Al2O3 < 20% with coal gangue or fly ash to prepare coal-based solid waste cementitious materials or coal-based solid waste filling materials.

2. The method for the graded and comprehensive utilization of coal gasification ash and solid waste as described in claim 1, characterized in that, In step S2, the physical separation refers to the separation of the fine slag using a spiral separator, screening machine, or flotation machine.

3. The method for the graded and comprehensive utilization of coal gasification ash and solid waste as described in claim 1, characterized in that, In step S3, the fine slag decarburization technology refers to preheating decarburization technology or pyrometallurgical combustion decarburization, which utilizes the residual carbon in the fine slag to undergo a rapid oxidation reaction, so that the fine slag filter cake is transformed into a second low-carbon ash slag.

4. The method for the comprehensive utilization of coal gasification ash and solid waste through a tiered and graded process as described in claim 1, characterized in that... In step S3, the carbon-rich ash can also be mixed with coal for reuse.

5. The method for the comprehensive utilization of coal gasification ash and solid waste through a tiered and graded process as described in claim 1, characterized in that... In step S4, the distinction between high-alumina ash slag, high-silica ash slag, and low-silica-alumina ash slag is made by using an X-ray fluorescence spectrometer to test the Al2O3 and SiO2 content in the first, second, and third low-carbon ash slags, thereby distinguishing the types of the first, second, and third low-carbon ash slags.

6. The method for the graded and comprehensive utilization of coal gasification ash and solid waste as described in claim 1, characterized in that, In step S4, the coarse slag separated in step S1 is directly tested using an X-ray fluorescence spectrometer to determine the type of coarse slag among high-alumina ash slag, high-silica ash slag, and low-silica-alumina ash slag.

7. The method for the graded and comprehensive utilization of coal gasification ash and solid waste as described in claim 1, characterized in that, In step S4, the coal-based solid waste cementitious material is used to bind building aggregates to form solid buildings, and the coal-based solid waste filling material is used to fill mines to control surface subsidence and rock strata movement.

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