High-proportion hydrogen-doped production system for coal-fired thermal power plant

Abstract

The utility model relates to a high-proportion hydrogen-doped production system for a coal-fired thermal power plant. The high-proportion hydrogen-doped production system comprises a power station boiler (1); the gasification furnace (2) is used for producing first synthesis gas by using oxygen and coal, and the first synthesis gas at least comprises CO2, CO, H2S and H2; the conversion device (3) is used for converting CO in the first synthesis gas into CO2; the heat recovery device (4) is used for recovering heat and water vapor of the first synthesis gas; the desulfurization and decarbonization device (5) is used for separating the second synthesis gas to respectively obtain CO2, H2S and third synthesis gas; and the component blending device (6) is used for blending the proportion of hydrogen in the third synthesis gas and providing the third synthesis gas to the power station boiler (1). Part of coal is gasified into first synthesis gas, CO in the first synthesis gas is converted into CO2, the desulfurization and decarbonization device (5) collects CO2 and H2S respectively, the hydrogen is fed into the power station boiler (1) for combustion after the proportion of the hydrogen is adjusted to be proper, the hydrogen is subjected to high-proportion blending combustion, and the purpose of carbon reduction is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon reduction in thermal power plants, and particularly relates to a high-proportion hydrogen-doped production system for a coal-fired thermal power plant. BACKGROUND

[0002] Traditional coal-fired thermal power plants mainly use coal as fuel, and a large amount of CO2 and pollutants are generated in the combustion process, which has high carbon emission intensity and is difficult to meet the current low-carbon development demand.

[0003] In the prior art, attempts are made to reduce carbon emissions by hydrogen-doped combustion, but the source of hydrogen is limited, and the syngas resources in the coal chemical process are not fully utilized. In addition, the existing technology lacks synergy in heat recovery, sulfur and carbon separation, and hydrogen allocation of coal syngas, and the energy efficiency and carbon reduction performance of thermal power plants need to be improved. CONTENT OF THE UTILITY MODEL

[0004] The application provides a high-proportion hydrogen-doped production system for a coal-fired thermal power plant, comprising:

[0005] A power station boiler for burning coal to produce steam and provide power generation for a steam turbine;

[0006] A gasifier for producing first syngas from oxygen and coal, the first syngas containing at least CO2, CO, H2S and H2;

[0007] A shift device for converting all or part of CO in the first syngas into CO2;

[0008] A heat recovery device for recovering heat and water vapor of the first syngas to convert the first syngas into second syngas;

[0009] A desulfurization and decarbonization device for separating the second syngas obtained by heat recovery to obtain CO2, H2S and third syngas, respectively;

[0010] A component allocation device for adjusting the proportion of hydrogen in the third syngas and providing the third syngas to the power station boiler.

[0011] Further, the component allocation device is used to mix the third syngas with the second syngas to adjust the proportion of hydrogen in the third syngas.

[0012] Further, the component allocation device is used to mix the third syngas with the converted CO2 to adjust the proportion of hydrogen in the third syngas.

[0013] Further, the component allocation device is used to mix the third syngas with the separated H2S to adjust the proportion of hydrogen in the third syngas.

[0014] Further, the production system further comprises a pressure reducing device arranged between the component adjusting device and the power plant boiler, for reducing the pressure of the adjusted third synthesis gas.

[0015] Further, an air separation device is arranged for separating oxygen from air and providing the oxygen to the gasifier; and / or,

[0016] An electrolysis water device is arranged for electrolyzing water and providing the obtained oxygen to the gasifier.

[0017] Further, the coal combusted by the power plant boiler is coal one, and the coal utilized by the gasifier is coal two, and the proportion of the coal two is higher than 20% of the total weight of the coal one and the coal two.

[0018] Further, the low-pressure steam obtained by the gasifier when producing the first synthesis gas is provided to the power plant or a heat user; and / or, the high-pressure steam and the low-pressure steam obtained by the shift and heat recovery are provided to the power plant or the heat user.

[0019] Further, the gasifier is one of a fixed bed, a fluidized bed and an entrained flow bed.

[0020] Further, the superheated steam utilized by the gasifier is obtained from a steam turbine extraction of the power plant or a steam boiler.

[0021] The above technical scheme of the utility model has at least the following beneficial technical effects:

[0022] In the production system of the application, the gasifier gasifies part of the coal into the first synthesis gas, and then converts CO in the first synthesis gas into CO2 in advance, the CO2 and H2S are collected by the desulfurization and decarbonization device, and the component adjusting device is arranged to participate in adjusting the proportion of hydrogen in the third synthesis gas, and after the appropriate mass ratio is reached, the third synthesis gas is sent to the power plant boiler for combustion, so that the hydrogen can be mixed and combusted at a high proportion, and the purpose of carbon reduction can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is a structure diagram of a high-proportion hydrogen production system of a coal-fired thermal power plant in one embodiment of the application.

[0025] Among them, Figure 1 The correspondence between the reference signs in and the component names is as follows:

[0026] 1. Power plant boiler; 2. Gasifier; 3. Shift converter; 4. Heat recovery unit; 5. Desulfurization and decarbonization unit; 6. Component blending unit; 7. Coal mill; 8. Steam turbine; 9. Pressure reducing unit. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0028] Currently, existing technologies lack sufficient synergy in heat recovery, sulfur and carbon separation, and hydrogen distribution from coal syngas, resulting in room for improvement in the energy efficiency and carbon reduction of thermal power plants.

[0029] To solve the above problems, such as Figure 1 As shown, one embodiment of this application provides a high-proportion hydrogen blending production system for a coal-fired power plant, comprising:

[0030] The power plant boiler 1 can burn pulverized coal to convert water into high-temperature, high-pressure steam, which serves as the power source for the steam turbine 8 to generate electricity. Simultaneously, the power plant boiler 1 can also burn combustible gas to aid combustion or replace coal. The equipment in this system for preparing the combustible gas to be burned in the power plant boiler 1 includes:

[0031] Gasifier 2 uses oxygen and coal to produce a first syngas, which contains at least CO2, CO, H2S, and H2; preferably, steam may also be added to participate in the synthesis of the first syngas. The dry basis composition of the first syngas may be 65% CO, 28% H2, 7% CO2, and 0.5% H2S.

[0032] In the shift converter 3, some or all of the CO in the first syngas is converted into CO2, facilitating centralized carbon capture in the subsequent desulfurization and decarbonization unit 5. The heat and water vapor in the first syngas are recovered through the heat recovery unit 4. In the shift converter 3, the shift reaction is CO + H2O → CO2 + H2. Since this reaction is exothermic, high-pressure steam is produced as a byproduct, which is supplied to the power plant for its own use or to heat users. During the heat recovery process, low-pressure steam is produced as a byproduct. The heat recovery unit 4 is equipped with a heat exchanger through which water flows, with the temperature controlled between 20 and 50°C. The heated water forms low-pressure steam, which can be supplied to the power plant for its own use or to heat users. The water vapor in the first syngas is condensed and discharged after heat exchange, transforming the first syngas into a dry second syngas. At this point, the dry basis composition of the gas includes, but is not limited to, 56% H2, 43% CO2, and 0.5% H2S, with other gases present in smaller quantities.

[0033] The dried second syngas enters the desulfurization and decarbonization unit 5 for separation, where CO2 and H2S are separated and collected, and the remainder is the third syngas. The desulfurization and decarbonization unit 5 can employ physical absorption separation, adsorption separation, membrane separation, and chemical absorption separation. Preferably, it uses low-temperature methanol washing physical absorption separation or NHD physical absorption separation. CO2 is used to produce chemical products to achieve carbon capture, and H2S is used to produce sulfur. At this point, the third syngas contains H2 under high pressure, the pressure of which depends on the gasification pressure.

[0034] Although a higher hydrogen content is better for the calorific value of the third syngas in this application, under existing technology and equipment, to reduce the probability of explosion during combustion of the third syngas, the hydrogen content in the third syngas needs to be adjusted by the component blending device 6 before entering the power plant boiler 1. Preferably, the blended mixture contains only a small amount of combustible gas other than hydrogen; therefore, the mass percentage of hydrogen can be adjusted to 60%-99%. The blended third syngas (mixed gas) remains under high pressure. A pressure reducing device is provided between the component blending device 6 and the power plant boiler 1 to reduce the pressure of the blended third syngas. Before entering the power plant boiler 1, the pressure can be reduced to a suitable level for combustion.

[0035] In the production system of this application, the gasifier 2 gasifies part of the coal into first syngas, and then the CO in the first syngas is converted into CO2 in advance. The desulfurization and decarbonization device 5 collects CO2 and H2S respectively. CO2 and H2S participate in the blending device 6 to blend the proportion of hydrogen in the third syngas. After reaching an appropriate mass ratio, it is sent to the power plant boiler 1 for combustion, which can enable high-proportion hydrogen co-firing and achieve the purpose of carbon reduction.

[0036] In one embodiment, the component blending device 6 can adjust the proportion of hydrogen in the third synthesis gas in various ways, including:

[0037] Optionally, the third syngas is mixed with the second syngas in the component blending device 6 to adjust the proportion of hydrogen in the third syngas.

[0038] Optionally, the third syngas is mixed with the CO2 obtained from conversion and decarbonization in the component blending device 6 to adjust the proportion of hydrogen in the third syngas.

[0039] Optionally, the third syngas is mixed with the H2S obtained from desulfurization in the component blending device 6 to adjust the proportion of hydrogen in the third syngas.

[0040] In one embodiment, the production system provides oxygen to the gasifier 2 in two ways: by using an air separator to separate oxygen from the air; or by using a water electrolysis device to electrolyze water, and the oxygen obtained from the electrolysis is provided to the gasifier 2.

[0041] In one alternative technical solution, the coal burned in the power plant boiler 1 is raw coal type 1; the coal used in the gasifier 2 is raw coal type 2. To achieve better early carbon capture and reduction effects, the proportion of raw coal type 2 is higher than 20% of the total weight of raw coal type 1 and raw coal type 2, thereby allowing more hydrogen to participate in combustion or replace coal. Both raw coal type 1 and raw coal type 2 are pulverized into pulverized coal by the coal mill 7, and the pulverized coal entering the gasifier 2 is also dried.

[0042] In one embodiment, the low-pressure steam obtained when the gasifier 2 produces the first syngas is provided to the power plant for its own use or to heat users; the slag and black water produced by the gasifier 2 are treated by a slag discharge device and a black water treatment device.

[0043] Furthermore, the gasifier 2 is one of the following types: fixed bed, fluidized bed, and entrained flow bed.

[0044] Furthermore, the power plant's steam turbine 8 extracts steam or a steam boiler provides superheated steam to the gasifier 2.

[0045] In addition, the production system of this application also involves some necessary steam pipelines, temperature regulation devices, pressure regulation devices, switching valves, etc. The specific structure of these devices or components is not limited in this application.

[0046] In the description of this utility model, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this utility model, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this application and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this application should be included within the protection scope of this application. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A coal-fired thermal power plant high proportion hydrogen blending production system, characterized in that, The production system comprises: a power station boiler (1) for burning coal to produce steam and provide power generation for a steam turbine (8); a gasifier (2) for producing a first synthesis gas from oxygen and coal, the first synthesis gas comprising at least CO2, CO, H2S and H2; a shift device (3) for converting all or part of CO in the first synthesis gas into CO2; a heat recovery device (4) for recovering heat and water vapor from the first synthesis gas to convert the first synthesis gas into a second synthesis gas; a desulfurization and decarbonization device (5) for separating the second synthesis gas obtained by heat recovery to obtain CO2, H2S and a third synthesis gas; a component adjusting device (6) for adjusting the proportion of hydrogen in the third synthesis gas and providing the third synthesis gas to the power station boiler (1).

2. The production system according to claim 1, characterized in that, The component adjusting device (6) is used for mixing the third synthesis gas with the second synthesis gas to adjust the proportion of hydrogen in the third synthesis gas.

3. The production system of claim 1, wherein, The component adjusting device (6) is used for mixing the third synthesis gas with the CO2 obtained by conversion to adjust the proportion of hydrogen in the third synthesis gas.

4. The production system of claim 1, wherein, The component adjusting device (6) is used for mixing the third synthesis gas with the H2S obtained by separation to adjust the proportion of hydrogen in the third synthesis gas.

5. The production system of claim 1, wherein, The production system further comprises a pressure reduction device (9) arranged between the component adjusting device (6) and the power station boiler (1) for reducing the pressure of the adjusted third synthesis gas.

6. The production system of claim 1, wherein, an air separation device for separating oxygen from air and providing the oxygen to the gasifier (2); and / or an electrolytic water device for electrolyzing water and providing the obtained oxygen to the gasifier (2).

7. The production system of claim 1, wherein, The coal burned by the power station boiler (1) is raw coal one; the coal used by the gasifier (2) is raw coal two; the proportion of raw coal two is higher than 20% of the total weight of raw coal one and raw coal two.

8. The production system of claim 1, wherein, The low-pressure steam obtained when the gasifier (2) produces the first synthesis gas is provided to the power plant for self-use or heat users; and / or The high-pressure steam and low-pressure steam produced by the shift and heat recovery are provided to the power plant for self-use or heat users.

9. The production system of claim 1, wherein, The type of the gasifier (2) is one of a fixed bed, a fluidized bed and an entrained flow bed.

10. The production system of claim 1, wherein, The source of the superheated steam used by the gasifier (2) is steam extraction from the power plant steam turbine (8) or a steam boiler.

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