Device and process for producing hydrogen and methane by coupling coal gasification with coal coking

Abstract

The present invention relates to the technical field of ammonia preparation devices, specifically a device for co-producing hydrogen and methane by coupling coal gasification and coal coking, which includes an exhaust gas purification tower. The exhaust gas purification tower is correspondingly arranged with an acetylene cracking furnace mixer, and a methanation catalytic reaction kettle, a liquefaction tank, and a gas mixing and preheating tank are successively arranged between the exhaust gas purification tower and the acetylene cracking furnace mixer. Moreover, the exhaust gas purification tower, the methanation catalytic reaction kettle, the liquefaction tank, the gas mixing and preheating tank, and the acetylene cracking furnace mixer are successively connected through pipelines. The beneficial effects are as follows: The device and process method for co-producing hydrogen and methane by coupling coal gasification and coal coking proposed by the present invention realize that the coke oven gas undergoes deammoniation, debenzolation, wet crude desulfurization, dry fine desulfurization, methanation, removal of carbon monoxide and high-carbon hydrocarbons, and finally cryogenic separation to produce liquid methane with a purity of more than 98%. At the same time, the by-products are clean H2 and N2 mixed gases for ammonia synthesis production.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia preparation devices, and specifically to a device and process method for co-producing hydrogen and methane by coupling coal gasification and coal coking. Background Art

[0002] Coke oven gas, due to its high combustible component content, belongs to high-calorific value gas, raw gas or crude gas. It refers to a combustible gas produced during the high-temperature dry distillation of a coking coal blend in a coke oven, along with the production of coke and tar products, and is a by-product of the coking industry.

[0003] In the prior art, coke oven gas is a mixture, and its yield and composition vary depending on the quality of the coking coal and the coking process conditions. Generally, 300 - 350 m3 (standard state) of coke oven gas can be produced per ton of dry coal. Its main components are hydrogen (55% - 60%) and methane (23% - 27%), and it also contains small amounts of carbon monoxide (5% - 8%), unsaturated hydrocarbons above C2 (2% - 4%), carbon dioxide (1.5% - 3%), oxygen (0.3% - 0.8%), and nitrogen (3% - 7%). Among them, hydrogen, methane, carbon monoxide, and unsaturated hydrocarbons above C2 are combustible components, while carbon dioxide, nitrogen, and oxygen are non-combustible components.

[0004] However, the by-products generated during the purification process of coke oven gas cannot be fully utilized, resulting in waste of resources. Moreover, after a large amount of these by-products leak out, environmental damage is caused. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and process method for co-producing hydrogen and methane by coupling coal gasification and coal coking, so as to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A device for co-producing hydrogen and methane by coupling coal gasification and coal coking, the device for co-producing hydrogen and methane by coupling coal gasification and coal coking includes:

[0007] An exhaust gas purification tower, which is correspondingly arranged with an acetylene cracking furnace mixer, and a methanation catalytic reaction kettle, a liquefaction tank, and a gas mixing and preheating tank are sequentially arranged between the exhaust gas purification tower and the acetylene cracking furnace mixer. The exhaust gas purification tower, the methanation catalytic reaction kettle, the liquefaction tank, the gas mixing and preheating tank, and the acetylene cracking furnace mixer are sequentially connected by pipelines. The acetylene cracking furnace mixer is connected to a catalytic reaction kettle by a pipeline, and the catalytic reaction kettle is connected to a hydrogenation reactor by a pipeline;

[0008] The space furnace is arranged side by side with the waste gas purification tower. The space furnace is connected to the spray purification tower through a pipeline. The spray purification tower is connected to the bag filter through a pipeline. The bag filter is connected to the water cooler through a pipeline. A desorption mechanism is arranged between the water cooler and the bag filter, and the desorption mechanism is connected to the PSA hydrogen extraction machine through a pipeline; and

[0009] The hydrogen delivery pipe is connected between the PSA hydrogen extraction machine and the acetylene cracking furnace mixer, and the PSA hydrogen extraction machine and the waste gas purification tower are connected through a desorbed gas delivery pipe.

[0010] Preferably, a waste gas injection pipe orifice is arranged on the surface of the waste gas purification tower.

[0011] Preferably, an ammonia discharge pipe orifice and a methane discharge pipe orifice are arranged on the surface of the hydrogenation reactor.

[0012] Preferably, the desorption mechanism includes an absorption tower and a desorption tower. The absorption tower is connected to the bag filter through a pipeline. The pipeline between the absorption tower and the bag filter is connected to the water cooler through a branch pipe. The desorption tower is connected to the PSA hydrogen extraction machine through a pipeline, and the absorption tower and the desorption tower are communicated through a throttling expansion pipe.

[0013] Preferably, electromagnetic valves are arranged on the pipe bodies of the hydrogen delivery pipe, the desorbed gas delivery pipe and the pipeline.

[0014] The process method for co-producing hydrogen and methane by coupling coal gasification with coal coking includes the following steps:

[0015] Purification and fine desulfurization of coke oven gas. The conventional purification of coke oven gas includes ammonia removal, benzene removal, and desulfurization. Wet desulfurization with a complex iron catalyst is used, and the clean coke oven gas is further subjected to dry fine desulfurization;

[0016] Under the temperature condition of 350°C - 450°C, the coke oven gas obtained by dry fine desulfurization undergoes a catalytic reaction under the action of a methanation catalyst to convert CO and CO2 in the coke oven gas into methane;

[0017] The coke oven gas is used to produce liquid methane by cryogenic separation. The obtained coke oven gas mixed with methane is dried and dehydrated, and then liquefied at -165°C to -162°C using a mixed refrigerant to produce liquid natural gas with a methane content of more than 98 wt.%, and the by-products are high-purity H2 and N2;

[0018] Partial oxidation and cracking, and compression of methane gas. Oxygen and the prepared liquid natural gas are mixed and preheated to 650 - 750°C, and then introduced into the acetylene cracking furnace mixer for mixing. At a temperature of 1300 - 1500°C, methane is partially oxidized and cracked to obtain a cracked gas containing acetylene;

[0019] Acetylene, formaldehyde and hydrogen are used to synthesize BDO through the alkyne-aldehyde method. Acetylene is separated from the cracked gas and purified as a raw material for synthesizing 1,4-butanediol (BDO). 1,4-butanediol (BDO) is prepared through a catalytic reaction, and the reaction is carried out in two steps. The first step: Using acetylene and formaldehyde as raw materials, 1,4-butynediol is generated under the action of a copper acetylide complex catalyst. The second step: 1,4-butynediol enters the hydrogenation reactor and undergoes hydrogenation with hydrogen under the action of a nickel-based catalyst to produce a crude 1,4-butanediol product.

[0020] Synthesis gas purification: The space furnace is used for coal gasification to produce synthesis gas. The produced synthesis gas is washed, purified, impurity-removed, and dust is removed, and the gas dust content is less than 1 mg / Nm 3 ;

[0021] The low-temperature methanol washing method is used to remove CO, ES, and COS in the shifted gas respectively. The qualified CO2 removed is used as the feed carrier gas for the gasifier. At the same time, the regenerated H2S is sent to the catalytic oxidation and recycling system. The low-temperature methanol wash is a physical absorption method. Under low temperature and high pressure, methanol absorbs CO, H2S, and COS in the absorption tower. The methanol solution that has absorbed CO2, H2S, and COS is called sulfur-rich methanol. After throttling and pressure reduction, a small amount of H2 and CO are also absorbed during the absorption process and are recovered after throttling and pressure reduction and flashing, releasing CO2. Then, CO2 and H2S are completely regenerated from the methanol solution in the hot state to obtain completely regenerated methanol. The cold energy required by the system comes from the ice machine and the throttling expansion of the high-pressure methanol solution that has absorbed CO2 and H2S, that is, the desorption of CO2 and each water cooler;

[0022] PSA hydrogen production: The gas desorbed after oxygen extraction is used as the heating fuel gas for the coke oven to ensure the coke oven temperature, and hydrogen is used to produce synthetic ammonia.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The device and process method for coupling coal gasification and coal coking to co-produce hydrogen and methane proposed by the present invention realize that the coke oven gas undergoes ammonia removal, benzene removal, wet rough desulfurization, dry fine desulfurization, methanation, removal of carbon monoxide and high-carbon hydrocarbons, and finally cryogenic separation to produce liquid methane with a purity of more than 98%. At the same time, the by-products are clean H2 and N2 mixed gas, which is used for synthetic ammonia production and the nylon industry. Hydrogen is used as a raw material for nylon chemical industry, and methane is used as a raw material for preparing acetylene by the partial oxidation method, which can be further used to produce 1,4-butanediol;

[0025] Using the space furnace gasification technology, after washing, purification, impurity removal, and dust removal, the gas dust content is less than 1 mg / Nm 3, low-temperature methanol washing, impurity removal, adsorption and desorption by PSA to obtain hydrogen with a purity of 99.9%. The remaining desorbed gas mainly consists of carbon monoxide and hydrogen. Hydrogen is used as a raw material for nylon chemical industry, and the desorbed gas is used as a raw material for coke oven recirculation heating. Among them, the carbon dioxide in the tail gas of low-temperature methanol washing is used as a pulverized coal carrier gas and transported to the gasifier to further improve the gasification efficiency;

[0026] The syngas produced by coal gasification is purified, impurity-removed and separated to obtain hydrogen and carbon monoxide. Hydrogen is used as a raw material gas for the nylon industry, and carbon monoxide is used as coke oven recirculation gas. The coke oven gas is impurity-removed and separated to obtain hydrogen and methane. Hydrogen is used as a raw material gas for the nylon industry, and methane is used as a raw material for the preparation of BDO by the acetylene aldehyde method. Through coupling, hydrogen and methane in the raw coal gas and coke oven gas are used for high-value utilization as downstream chemical raw materials, and carbon monoxide is used as fuel for coke oven heating. Brief Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of the present invention;

[0028] Figure 2 It is a process flow chart of the process method of the present invention.

[0029] In the figure: waste gas purification tower 1, methanation catalytic reaction kettle 2, liquefied tank 3, gas mixing and preheating tank 4, acetylene cracking furnace mixer 5, catalytic reaction kettle 6, hydrogenation reactor 7, waste gas injection pipe orifice 8, ammonia discharge pipe orifice 9, methane discharge pipe orifice 10, aerospace furnace 11, spray purification tower 12, bag filter 13, absorption tower 14, desorption tower 15, throttling expansion pipe 16, water cooler 17, PSA hydrogen extraction machine 18, hydrogen transmission pipe 19, desorbed gas transmission pipe 20. Detailed Embodiments

[0030] In order to clearly and completely describe the purpose, technical solution of the present invention and make the advantages more clear, the following further details the embodiments of the present invention with reference to the drawings. It should be understood that the specific embodiments described herein are some embodiments of the present invention, rather than all embodiments, and are only used to explain the embodiments of the present invention, not to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "middle", "upper", "lower", "left", "right", "inner", "outer", "top", "bottom", "side", "vertical", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "one", "first", "second", "third", "fourth", "fifth", "sixth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] For the purposes of simplicity and illustration, the principles of the embodiments are mainly described by reference to examples. In the following description, many specific details are set forth to provide a thorough understanding of the embodiments. However, it is obvious that for those of ordinary skill in the art, these embodiments may not be limited to these specific details in practice. In some instances, well-known methods and structures are not described in detail to avoid unnecessarily obscuring these embodiments. Additionally, all embodiments can be used in combination with each other.

[0034] Please refer to Figures 1 to 2 , the present invention provides a technical solution: a device for co-producing hydrogen and methane by coupling coal gasification and coal coking. The device for co-producing hydrogen and methane by coupling coal gasification and coal coking includes an exhaust gas purification tower 1, which is correspondingly arranged with an acetylene cracking furnace mixer 5. Between the exhaust gas purification tower 1 and the acetylene cracking furnace mixer 5, a methanation catalytic reaction kettle 2, a liquefaction tank 3, and a gas mixing and preheating tank 4 are sequentially arranged. The exhaust gas purification tower 1, the methanation catalytic reaction kettle 2, the liquefaction tank 3, the gas mixing and preheating tank 4, and the acetylene cracking furnace mixer 5 are sequentially connected by pipelines. The acetylene cracking furnace mixer 5 is connected with a catalytic reaction kettle 6 by a pipeline, the catalytic reaction kettle 6 is connected with a hydrogenation reactor 7 by a pipeline. An exhaust gas injection pipe orifice 8 is arranged on the surface of the exhaust gas purification tower 1, and an ammonia discharge pipe orifice 9 and a methane discharge pipe orifice 10 are arranged on the surface of the hydrogenation reactor 7;

[0035] The space furnace 11 and the waste gas purification tower 1 are arranged side by side. The space furnace 11 is connected to the spray purification tower 12 through a pipeline. The spray purification tower 12 is connected to the bag filter 13 through a pipeline. The bag filter 13 is connected to the water cooler 17 through a pipeline. And a desorption mechanism is arranged between the water cooler 17 and the bag filter 13. The desorption mechanism is connected to the PSA hydrogen production machine 18 through a pipeline; the desorption mechanism includes an absorption tower 14 and a desorption tower 15. The absorption tower 14 is connected to the bag filter 13 through a pipeline. The pipeline between the absorption tower 14 and the bag filter 13 is connected to the water cooler 17 through a branch pipe. And the desorption tower 15 is connected to the PSA hydrogen production machine 18 through a pipeline. The absorption tower 14 and the desorption tower 15 are communicated through a throttling expansion pipe 16;

[0036] The hydrogen delivery pipe 19 is connected between the PSA hydrogen production machine 18 and the acetylene cracking furnace mixer 5. The PSA hydrogen production machine 18 and the waste gas purification tower 1 are connected through a desorbed gas delivery pipe 20. Electromagnetic valves are arranged on the pipe bodies of the hydrogen delivery pipe 19, the desorbed gas delivery pipe 20 and the pipeline.

[0037] A process method for co-producing hydrogen and methane by coupling coal gasification and coal coking is characterized in that it includes the following steps:

[0038] Purification and fine desulfurization of coke oven gas. The conventional purification of coke oven gas includes ammonia removal, benzene removal, and desulfurization. Wet desulfurization with a complex iron catalyst, and then the clean coke oven gas is further subjected to dry fine desulfurization;

[0039] Under the temperature condition of 350°C - 450°C, the coke oven gas obtained by dry fine desulfurization undergoes a catalytic reaction under the action of a methanation catalyst to convert CO and CO2 in the coke oven gas into methane;

[0040] The coke oven gas is used to produce liquid methane by cryogenic separation. The obtained coke oven gas mixed with methane is dried and dehydrated, and then liquefied with a mixed refrigerant at -165°C to -162°C to produce liquid natural gas with a methane content of more than 98 wt.%, and the by-products are high-purity H2 and N2;

[0041] Partial oxidation and cracking, and compression of methane gas. Oxygen and the prepared liquid natural gas are mixed and preheated to 650 - 750°C, and then introduced into the acetylene cracking furnace mixer for mixing. At a temperature of 1300 - 1500°C, methane is partially oxidized and cracked to obtain cracked gas containing acetylene;

[0042] Acetylene, formaldehyde and hydrogen are used to synthesize BDO through the alkyne-aldehyde method. Acetylene is separated from the cracked gas and purified as a raw material for synthesizing 1,4-butanediol (BDO). 1,4-butanediol (BDO) is prepared through a catalytic reaction, and the reaction is carried out in two steps. The first step: Using acetylene and formaldehyde as raw materials, 1,4-butynediol is generated under the action of a copper acetylide complex catalyst. The second step: 1,4-butynediol enters the hydrogenation reactor and undergoes hydrogenation with hydrogen under the action of a nickel-based catalyst to produce a crude 1,4-butanediol product.

[0043] Synthesis gas purification: The space furnace is used for coal gasification to produce synthesis gas. The produced synthesis gas is washed, purified, desulfurized, and the dust is removed, and the gas dust content is less than 1 mg / Nm 3 ;

[0044] The low-temperature methanol washing method is used to remove CO, ES, and COS in the shifted gas respectively. The qualified CO2 removed is used as the feed carrier gas for the gasifier. At the same time, the regenerated H2S is sent to the catalytic oxidation and recycling system. The low-temperature methanol wash is a physical absorption method. Under low temperature and high pressure, methanol absorbs CO, H2S, and COS in the absorption tower. The methanol solution that has absorbed CO2, H2S, and COS is called sulfur-rich methanol. After throttling and pressure reduction, a small amount of H2 and CO are also absorbed during the absorption process and are recovered after throttling and pressure reduction and flashing, releasing CO2. Then, CO2 and H2S are completely regenerated from the methanol solution in the hot state to obtain completely regenerated methanol. The cold energy required by the system comes from the ice machine and the throttling expansion of the high-pressure methanol solution that has absorbed CO2 and H2S, that is, the desorption of CO2 and each water cooler;

[0045] PSA hydrogen production: The off-gas after oxygen extraction is used as the heating fuel gas for the coke oven to ensure the coke oven temperature, and hydrogen is used to produce synthetic ammonia.

[0046] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An apparatus for co-producing hydrogen and methane by coupling coal gasification and coal coking, characterized in that: The device for co-producing hydrogen and methane by coupling coal gasification and coal coking includes: An exhaust gas purification tower (1), which is arranged corresponding to an acetylene cracking furnace mixer (5). Between the exhaust gas purification tower (1) and the acetylene cracking furnace mixer (5), there are successively a methanation catalytic reaction kettle (2), a liquefaction tank (3), and a gas mixing and preheating tank (4). The exhaust gas purification tower (1), the methanation catalytic reaction kettle (2), the liquefaction tank (3), the gas mixing and preheating tank (4), and the acetylene cracking furnace mixer (5) are successively connected by pipelines. The acetylene cracking furnace mixer (5) is connected with a catalytic reaction kettle (6) through a pipeline, and the catalytic reaction kettle (6) is connected with a hydrogenation reactor (7) through a pipeline; A space furnace (11), which is arranged side by side with the exhaust gas purification tower (1). The space furnace (11) is connected with a spray purification tower (12) through a pipeline. The spray purification tower (12) is connected with a bag filter (13) through a pipeline. The bag filter (13) is connected with a water cooler (17) through a pipeline. And a desorption mechanism is arranged between the water cooler (17) and the bag filter (13). The desorption mechanism is connected with a PSA hydrogen extraction machine (18) through a pipeline; and A hydrogen delivery pipe (19), which is connected between the PSA hydrogen extraction machine (18) and the acetylene cracking furnace mixer (5). The PSA hydrogen extraction machine (18) and the exhaust gas purification tower (1) are connected by a desorbed gas delivery pipe (20).

2. The device for co-producing hydrogen and methane by coupling coal gasification and coal coking according to claim 1, characterized in that: An exhaust gas injection nozzle (8) is arranged on the surface of the exhaust gas purification tower (1).

3. The device for co-producing hydrogen and methane by coupling coal gasification and coal coking according to claim 1, characterized in that: An ammonia discharge nozzle (9) and a methane discharge nozzle (10) are arranged on the surface of the hydrogenation reactor (7).

4. The device for co-producing hydrogen and methane by coupling coal gasification and coal coking according to claim 1, wherein: The desorption mechanism includes an absorption tower (14) and a desorption tower (15). The absorption tower (14) is connected with the bag filter (13) through a pipeline. The pipeline between the absorption tower (14) and the bag filter (13) is connected with the water cooler (17) through a branch pipe. And the desorption tower (15) is connected with the PSA hydrogen extraction machine (18) through a pipeline. The absorption tower (14) and the desorption tower (15) are communicated through a throttling expansion pipe (16).

5. The device for co-producing hydrogen and methane by coupling coal gasification and coal coking according to claim 1, wherein: Electromagnetic valves are arranged on the pipe bodies of the hydrogen delivery pipe (19), the desorbed gas delivery pipe (20), and the pipelines.

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