Device for preparing LNG (Liquefied Natural Gas) and co-producing hydrogen from raw coke oven gas

Abstract

The utility model relates to a device for preparing LNG (Liquefied Natural Gas) from raw gas and co-producing hydrogen. The device comprises a pretreatment subunit, a conversion unit, a desulfurization and decarbonization unit, a methanation unit and a cryogenic separation unit which are connected in sequence, the pretreatment subunit comprises a cooler, tar capturing equipment, first compression equipment, first deamination equipment, first desulfurization equipment and detarring adsorption equipment which are connected in sequence; the conversion unit comprises second compression equipment, preheating equipment, a pre-conversion reactor, humidifying equipment and a conversion reactor which are connected in sequence; the desulfurization and decarbonization unit comprises second deamination equipment, second desulfurization equipment, an absorption tower, hydrogenation equipment and third desulfurization equipment which are connected in sequence; the cryogenic separation unit comprises drying equipment, heavy hydrocarbon removal equipment and a cold box which are connected in sequence. By adopting the device, the LNG product and the hydrogen can be obtained by treating the raw gas, and the yields of the LNG and the H2 can be adjusted at any time according to the fluctuation of the product price, so that the maximization of the product value is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of waste gas treatment, in particular to a device for preparing LNG from waste gas and co-producing hydrogen. Background Art

[0002] At present, due to the complex composition of raw coal gas and the relatively high content of methane, carbon monoxide and hydrogen, the processing process is difficult. If the effective components in the raw coal gas can be reasonably utilized, it will effectively alleviate the risk of severe shortage of LNG in winter and provide other chemical raw materials for downstream.

[0003] There are two main process routes for producing downstream products from waste gas:

[0004] 1) Hydrogen production from raw coal gas, that is, after the raw coal gas is pretreated, the hydrogen in the gas is recovered and reused through PSA;

[0005] 2) The process of producing hydrogen from waste gas and co-producing LNG, that is, firstly through pretreatment, compression purification, conversion hydrogenation, desulfurization and decarbonization, methanation, pressure swing adsorption, and cryogenic separation to obtain high-purity hydrogen and LNG products:

[0006] For example, CN214734512U provides a system for producing hydrogen from raw coal gas, which relates to the field of equipment for producing hydrogen from raw coal gas. The system for producing hydrogen from raw coal gas includes a gas compression device, a temperature-swinging adsorption device, and two or more concentration and purification mechanisms. The outlet end of the gas compression device is connected to the inlet end of the temperature-swinging adsorption device. The two or more concentration and purification mechanisms are connected in parallel and are all connected to the outlet end of the temperature-swinging adsorption device. The concentration and purification mechanism includes a concentration adsorption device, a deoxygenation device, and a purification adsorption device. The concentration adsorption device, the deoxygenation device, and the purification adsorption device are sequentially arranged in series along the flow direction of the raw coal gas. However, in the scheme, only the hydrogen in the raw coal gas is extracted, and the other components in the raw coal gas are wasted.

[0007] CN108609582A provides a process for producing hydrogen from raw coal gas. First, the raw raw coal gas is compressed, washed for desalination, pretreated, and subjected to sulfur-resistant wide temperature conversion in sequence. The converted gas obtained is sent to a pressure swing adsorption hydrogen concentration unit to obtain hydrogen-rich gas and desorption gas (fuel gas). The hydrogen-rich gas is then sent to a pressure swing adsorption hydrogen purification unit to obtain a hydrogen product with a purity greater than 99.9 vol% and a (CO+CO2) content less than 20 ppm. The desorption gas is sent to be mixed with the stripping acid gas sent from a coal tar hydrogenation device, and then sent to a wet desulfurization unit to remove H2S to obtain purified fuel gas. In this scheme, only the hydrogen in the raw coal gas is extracted for use, and other effective components are discharged as tail gas, wasting resources.

[0008] CN112897464A provides a process for producing hydrogen and LNG from raw coal gas with methanation. The process uses raw coal gas from pyrolysis of low-rank coal as raw material, and undergoes pretreatment, compression purification, conversion hydrogenation, desulfurization and decarbonization, methanation, pressure swing adsorption, and cryogenic separation to obtain high-purity hydrogen and LNG products. The process is complex, energy-intensive, and has poor product flexibility. At the same time, the loss of effective gas in the analyzed gas is large.

[0009] CN214243809U discloses a system for producing hydrogen from waste coal gas and co-producing LNG, which adopts a decoking unit, a primary pressurization, cooling and liquid separation unit, a secondary pressurization unit, a pretreatment unit, a tertiary pressurization unit, a deoxygenation conversion unit, a desulfurization unit, a decarbonization unit, a methane concentration unit, a hydrogen purification unit and an LNG production unit; the concentration process of this process produces desorption gas, which carries equivalent effective components, resulting in a waste of effective gas. At the same time, the product has no adjustment function and cannot meet the market fluctuations, resulting in insufficient product competitiveness.

[0010] In summary, the existing solutions for utilizing raw coal gas still have the defects of poor utilization efficiency of raw coal gas and poor product diversity. Utility Model Content

[0011] In view of the problems existing in the prior art, the purpose of the utility model is to provide a device for preparing LNG and co-producing hydrogen from raw coal gas, so as to solve the defects of poor raw coal gas utilization efficiency and poor product diversity in the existing schemes for utilizing raw coal gas.

[0012] To achieve this purpose, the utility model adopts the following technical solutions:

[0013] The utility model provides a device for preparing LNG from raw coal gas and co-producing hydrogen, the device for preparing LNG from raw coal gas and co-producing hydrogen comprises:

[0014] A pretreatment subunit, a conversion unit, a desulfurization and decarbonization unit, a methanation unit and a cryogenic separation unit connected in sequence;

[0015] The pretreatment subunit includes a cooler, a tar capture device, a first compression device, a first deamination device, a first desulfurization device and a detar adsorption device connected in sequence;

[0016] The conversion unit includes a second compression device, a preheating device, a pre-conversion reactor, a humidification device and a conversion reactor connected in sequence;

[0017] The desulfurization and decarbonization unit comprises a second deamination device, a second desulfurization device, an absorption tower, a hydrogenation device and a third desulfurization device connected in sequence;

[0018] The methanation unit comprises a methanation reactor in sequence;

[0019] The cryogenic separation unit comprises a drying device, a heavy hydrocarbon removal device and a cold box which are connected in sequence.

[0020] The utility model provides a device for preparing LNG and co-producing hydrogen from raw coal gas, which separates the products by passing the raw coal gas through a pretreatment unit, a conversion unit, a desulfurization and decarbonization unit, a methanation unit, and a cryogenic separation unit, thereby obtaining LNG products and hydrogen. The outputs of LNG and H2 can be adjusted at any time according to fluctuations in product prices, thereby maximizing the value of the products and providing an optimal route for the long-term development of the enterprise.

[0021] As a preferred technical solution of the utility model, the material outlet of the cooler is connected to the feed inlet of the tar capture equipment;

[0022] The discharge port of the tar catching device is connected to the feed port of the humidifying device;

[0023] The cooler is a transverse tube cooler; the tar capture equipment includes an electric tar capture equipment; and the humidification equipment includes a wet gas cabinet.

[0024] As a preferred technical solution of the utility model, the material outlet of the tar capture device in the pretreatment subunit is connected to the feed inlet of the first compression device;

[0025] The material outlet of the first compression device is connected to the feed inlet of the first deamination device;

[0026] The material outlet of the first deamination equipment is connected to the feed inlet of the first desulfurization equipment;

[0027] A spray device is provided on the top of the first deamination device;

[0028] The first deammoniation equipment is equipped with a circulation pump;

[0029] The first compression equipment includes a screw compressor; the first deamination equipment includes a cooling deamination tower; and the desulfurization equipment includes a wet desulfurization tower.

[0030] As a preferred technical solution of the utility model, the material outlet of the first desulfurization equipment is connected to the feed inlet of the detarring adsorption equipment;

[0031] The discharge port of the detarring adsorption device is connected to the feed port of the second compression device;

[0032] The material outlet of the second compression device is connected to the material inlet of the preheating device;

[0033] The material outlet of the preheating device is connected to the feed inlet of the pre-transformation reactor;

[0034] The detarring adsorption equipment comprises a TSA adsorption equipment;

[0035] The preheating device comprises an electric heater;

[0036] The pre-transformation reactor is equipped with a deoxygenated water supply device.

[0037] As a preferred technical solution of the utility model, an electric heating device is arranged between the shift reactor and the second deamination device;

[0038] The second deammoniation equipment is equipped with a circulation pump.

[0039] As a preferred technical solution of the utility model, the material outlet of the shift reactor is connected to the feed inlet of the second deamination equipment;

[0040] The discharge port of the second deamination equipment is connected to the feed port of the second desulfurization equipment;

[0041] The discharge port of the second desulfurization equipment is connected to the feed port of the absorption tower;

[0042] A heat exchange device is arranged between the absorption tower and the hydrogenation device.

[0043] As a preferred technical solution of the utility model, the hydrogenation equipment includes at least 2 stages of hydrogenation equipment;

[0044] The second desulfurization equipment includes at least two stages of desulfurization equipment.

[0045] As a preferred technical solution of the present utility model, a preheating heat exchange device is arranged between the material outlet of the third desulfurization equipment and the methanation reactor.

[0046] As a preferred technical solution of the utility model, the heat medium inlet of the preheating heat exchange equipment is connected to the material outlet of the methanation reactor.

[0047] As a preferred technical solution of the utility model, the heat medium outlet after heat exchange of the preheating heat exchange device is connected to the drying device;

[0048] The nitrogen outlet of the cold box is connected to the regeneration gas inlet of the heavy hydrocarbon removal equipment.

[0049] Compared with the existing technical solutions, the utility model has the following beneficial effects:

[0050] The device provided by the utility model realizes efficient utilization of raw coal gas by coupling various devices, can realize rapid separation of useful components in the raw coal gas, and improves the separation effect. At the same time, due to the specific selection and connection design of each device, various useful components in the raw coal gas can be fully utilized, such as LNG, hydrogen, nitrogen, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of a device for preparing LNG from raw coal gas and co-producing hydrogen, provided in an embodiment of the utility model.

[0052] In the figure: 1-cooler, 2-tar capture equipment, 3-first compression equipment, 4-first deamination equipment, 5-first desulfurization equipment, 6-detar adsorption equipment, 7-second compression equipment, 8-preheating equipment, 9-pre-conversion reactor, 10-humidification equipment, 11-conversion reactor, 12-electric heating equipment, 13-second deamination equipment, 14-second desulfurization equipment, 15-absorption tower, 16-hydrogenation equipment, 17-third desulfurization equipment, 18-methanation reactor, 19-drying equipment, 20-heavy hydrocarbon removal equipment, 21-cold box;

[0053] A-raw gas, B-desulfurized rich liquid, C-desulfurized and decarbonized rich liquid, D-hydrogen, E-LNG, F-negative nitrogen tail gas.

[0054] The utility model is further described in detail below. However, the following examples are only simple examples of the utility model and do not represent or limit the scope of protection of the utility model. The scope of protection of the utility model shall be subject to the claims. DETAILED DESCRIPTION

[0055] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0056] This embodiment provides a device for preparing LNG from raw coal gas and co-producing hydrogen. Figure 1 As shown, the device for preparing LNG from raw coal gas and co-producing hydrogen includes:

[0057] A pretreatment subunit, a conversion unit, a desulfurization and decarbonization unit, a methanation unit and a cryogenic separation unit connected in sequence;

[0058] The pretreatment subunit includes a cooler 1, a tar capture device 2, a first compression device 3, a first deammonification device 4, a first desulfurization device 5 and a detar adsorption device 6 connected in sequence;

[0059] The conversion unit comprises a second compression device 7, a preheating device 8, a pre-conversion reactor 9, a humidification device 10 and a conversion reactor 11 connected in sequence;

[0060] The desulfurization and decarbonization unit includes a second deamination device 13, a second desulfurization device 14, an absorption tower 15, a hydrogenation device 16 and a third desulfurization device 17 connected in sequence;

[0061] The methanation unit comprises a methanation reactor 18 in sequence;

[0062] The cryogenic separation unit comprises a drying device 19, a heavy hydrocarbon removal device 20 and a cold box 21 which are connected in sequence.

[0063] Wherein, the material outlet of the cooler 1 in the pretreatment subunit is connected to the feed inlet of the tar capture device 2;

[0064] The discharge port of the tar capture device 2 is connected to the feed port of the first compression device 3;

[0065] Specifically, the cooler 1 is a transverse tube cooler 1; the cooler 1 of the utility model can adopt other cooling equipment or heat exchange cooling equipment commonly used in the field to achieve the cooling function, ensuring that the raw coal gas A is cooled to 30-50°C.

[0066] Specifically, the tar capture device 2 includes an electric tar capture device 2 .

[0067] The tar capture device 2 in the utility model can also be replaced by a device with the same function to ensure that the tar content in the raw gas is reduced to 20 mg / Nm 3 Below and naphthalene down to 50mg / Nm 3 The following will do.

[0068] Specifically, the humidification device 10 includes a wet gas cabinet.

[0069] In the utility model, the raw coal gas after detarring is introduced into a wet gas cabinet for storage and supplemented with a certain humidity.

[0070] In the utility model, the raw gas A is pretreated by the pretreatment unit to obtain a relatively clean raw gas, specifically, the raw gas is cooled, tar is captured, pressurized once, roughly desulfurized and detarred.

[0071] Wherein, the material outlet of the tar capture device 2 in the pretreatment subunit is connected to the feed inlet of the first compression device 3;

[0072] The material outlet of the first compression device 3 is connected to the feed inlet of the first deamination device 4;

[0073] The material outlet of the first deamination equipment 4 is connected to the feed inlet of the first desulfurization equipment 5;

[0074] A spray device is provided on the top of the first deamination device 4;

[0075] The first deammoniation equipment 4 is equipped with a circulation pump;

[0076] The circulating pump provided in the first deammonification equipment 4 is used to circulate the deammonification liquid.

[0077] Specifically, the first compression device 3 includes a screw compressor; other compression devices may also be used as a substitute, as long as the gas can be compressed to 0.5-0.7 MPaG.

[0078] Specifically, the first deamination device 4 includes a cooling deamination tower; other devices with the same function may also be used as a replacement, such as a combined device formed by combining a cooling device and a deamination device, or other similar devices in the art, to ensure that the ammonia in the raw gas after deamination is reduced to 100 mg / Nm 3 The following will do.

[0079] Specifically, the first desulfurization equipment 5 includes a wet desulfurization tower; other desulfurization towers may also be used as a substitute, such as a dry desulfurization tower that can achieve the same effect, and other desulfurization equipment commonly used in the art, to ensure that the hydrogen sulfide in the raw gas obtained after desulfurization is reduced to 50 mg / Nm 3 The following will do.

[0080] In the present invention, the first desulfurization equipment 5 also produces a desulfurized rich liquid B, and the sulfur therein can be recovered and utilized through further processing, and the desulfurized liquid is then returned for reuse.

[0081] Wherein, the material outlet of the first desulfurization equipment 5 is connected to the feed inlet of the detarring adsorption equipment 6;

[0082] The discharge port of the detarring adsorption device 6 is connected to the feed port of the second compression device 7 .

[0083] In the present invention, the second compression device 7 can be a commonly used gas compression device in the art, and it is sufficient to ensure that the gas pressure can be increased to 3.0-4.0 MPaG.

[0084] Wherein, the material outlet of the second compression device 7 is connected to the feed inlet of the preheating device 8;

[0085] In the present invention, the preheating device 8 includes a transformable preheater or a heat exchange preheater to ensure that the temperature of the preheated gas can reach 200-210°C.

[0086] The material outlet of the preheating device 8 is connected to the feed inlet of the pre-transformation reactor 9 .

[0087] In the present invention, the pre-transformation reactor 9 is arranged to remove oxygen from the airflow. After being treated by the pre-transformation reactor 9, the oxygen in the airflow is reduced to below 50 ppm. At the same time, the temperature of the airflow after being treated by the pre-transformation reactor 9 is increased to about 320-330°C.

[0088] Wherein, the detarring adsorption device 6 comprises a TSA adsorption device.

[0089] In the utility model, the absorption medium in the TSA adsorption equipment removes carbon dioxide and hydrogen sulfide in the conversion gas, and the hydrogen sulfide is removed to 5mg / Nm 3 Below, carbon dioxide is removed to below 50ppm.

[0090] Wherein, the preheating device 8 includes an electric heater.

[0091] Wherein, the pre-transformation reactor 9 is equipped with a deoxygenated water supply device.

[0092] Among them, the humidification equipment 10 is a humidifier, and the humidification medium used in humidification is desalted water, which can be specifically selected as water or other commonly used desalting agents in the field. The humidifier mainly mixes the process gas with desalted water, which increases the water-gas ratio of the process gas and cools the process gas at the same time.

[0093] Wherein, an electric heating device 12 is provided between the shift reactor 11 and the second deammoniation device 13;

[0094] The second deammoniation equipment 13 is equipped with a circulation pump.

[0095] In the present invention, the shift reactor 11 includes at least two shift reactors, and the temperature of the material entering the first shift reactor is 180-190° C., thereby providing a basis for the first shift reaction and recovering excess heat energy.

[0096] In the utility model, a heat exchange device is arranged between the primary conversion reactor and the secondary conversion reactor to reduce the temperature of the air flow to 180-190°C to provide a basis for the secondary conversion reaction and to recover the excess heat energy.

[0097] The material outlet of the shift reactor 11 is connected to the feed inlet of the second deamination equipment 13 .

[0098] The discharge port of the second deamination equipment 13 is connected to the feed port of the second desulfurization equipment 14 .

[0099] In the present invention, the second deammonification equipment 13 is equipped with a circulation pump to realize the recycling of the deammonification liquid.

[0100] The discharge port of the second desulfurization equipment 14 is connected to the feed port of the absorption tower 15 .

[0101] In the present invention, the second desulfurization equipment 14 simultaneously produces a desulfurized rich liquid B, and after further processing, the sulfur therein can be recovered and utilized, and the desulfurized liquid is then returned for reuse.

[0102] Wherein, a heat exchange device is arranged between the absorption tower 15 and the hydrogenation device 16 .

[0103] In the present invention, the absorption tower 15 will simultaneously produce desulfurized and decarbonized rich liquid C, which can be regenerated and reused after further treatment.

[0104] In the present invention, a heat exchange device is arranged between the absorption tower 15 and the hydrogenation device 16 to heat the gas flow to 350-360° C., thus laying a foundation for the subsequent hydrogenation reaction performed by the hydrogenation device 16 .

[0105] The hydrogenation equipment 16 includes at least two stages of hydrogenation equipment 16 .

[0106] Wherein, the second desulfurization equipment 14 includes at least two stages of desulfurization equipment.

[0107] In the present invention, after being treated by the hydrogenation device 16 and the second desulfurization device 14, the concentration of hydrogen sulfide in the gas stream is reduced to 0.1 mg / Nm 3 The following meets the needs of subsequent methanogenesis.

[0108] Wherein, a preheating heat exchange device is arranged between the material outlet of the third desulfurization device 17 and the methanation reactor 18 .

[0109] Wherein, the heat medium inlet of the preheating heat exchange device is connected to the material outlet of the methanation reactor 18.

[0110] In the utility model, the methanogenic gas flow is preheated and then methanogenic, so CO and CO2 can be removed, and after the removal, CO+CO2 is less than 10ppm.

[0111] The outlet of the heat medium after heat exchange of the preheating heat exchange device is connected to the drying device 19 .

[0112] In the utility model, the preheating heat exchange equipment preheats the material by heat exchange.

[0113] In the present invention, the drying device 19 is arranged according to the three-tower process in the art, and water is removed to below 1 ppm by molecular sieve.

[0114] Furthermore, an electric heating device is provided between the methanation reactor 18 and the drying device 19 to ensure that the material entering the drying device 19 meets the drying operation requirements.

[0115] Furthermore, in the present invention, the heavy hydrocarbon removal unit is mainly used to remove the benzene component in the gas, and the removal reagent can be selected from commonly used removal reagents in the field. For example, carbon materials are selected for adsorption removal, such as porous adsorption materials such as activated carbon.

[0116] The nitrogen outlet of the cold box 21 is connected to the regeneration gas inlet of the heavy hydrocarbon removal equipment 20 .

[0117] In the utility model, hydrogen D, LNG (liquefied gas) E and negative nitrogen tail gas F are obtained after separation in a cold box.

[0118] Furthermore, the utility model provides a specific process of the device for preparing LNG and co-producing hydrogen from the above-mentioned raw coal gas, which is as follows:

[0119] 1. Pretreatment: The raw gas A first enters the cooler 1, which uses circulating cooling water to cool to 30-50°C, and then passes the cooled gas into the electric tar collector to reduce the tar to 20mg / Nm 3 Below, naphthalene is reduced to 50mg / Nm 3 Below, the pressure drops to 2.5-3.5 kPaG, and then the resulting gas is passed into a wet gas holder with a pressure of 3-4 kPaG.

[0120] The raw gas from the wet gas tank is compressed in one stage. In the first stage of compression, the gas is compressed to 0.5-0.7MPaG by a screw compressor. The outlet temperature of the screw compressor is 80-90℃. After that, it enters the cooling and deammonification tower and is cooled to 35-45℃ by circulating water. At the same time, water is sprayed on the top to remove ammonia to 100mg / Nm 3 The cooled raw gas enters the wet desulfurization tower, where the PDS desulfurization process is used to remove hydrogen sulfide to 50mg / Nm 3 Below, the desulfurization liquid regenerates sulfur as a byproduct, and the wet desulfurization unit removes ammonia to 50mg / Nm 3 The desulfurized raw gas enters the TSA unit to remove tar and naphthalene, and removes tar and naphthalene to 1mg / Nm 3 , gas shift unit after temperature swing adsorption.

[0121] 2. Conversion treatment: The pretreated raw coal gas is compressed in two stages and pressurized to 3.0-4.0MPaG, and then sent to the conversion preheater for preheating. After heat exchange to 200-210°C, it enters the pre-conversion reactor 9 to remove oxygen to below 50ppm. At the same time, the material temperature is raised to 320-330°C and deoxygenated water is added in a certain proportion. After heat exchange to 180-190°C, it enters the primary conversion reactor. The material outlet temperature of the primary conversion reactor is raised to 350-360°C. After heat exchange again, the temperature drops to 180-190°C and enters the secondary conversion reactor. The outlet temperature of the secondary conversion reactor is raised to 220°C. After heat exchange and cooling to 40°C, water is separated and then it enters the desulfurization and decarbonization unit. After two-stage conversion, the CO conversion rate is more than 99%.

[0122] 3. Desulfurization and decarbonization: The converted coal gas enters the second desulfurization process and uses the PDS desulfurization process to remove hydrogen sulfide to 25mg / Nm 3Next, the desulfurization liquid regenerates the by-product sulfur, and then the gas phase enters the secondary deamination tower for the second deamination, which is removed by the circulating liquid in the tower bottom, and fresh water is sprayed on the top to remove ammonia to 5mg / Nm 3 The gas material then enters the absorption tower 15 at 2.8-2.9 MPaG. The MEDA solution in the absorption tower 15 removes carbon dioxide and hydrogen sulfide from the conversion gas, and the hydrogen sulfide is removed to 5 mg / Nm 3 The carbon dioxide is removed to below 50ppm. The removed carbon-rich tail gas contains a small amount of hydrogen sulfide. Consider using the PDS desulfurization process to remove qualified hydrogen sulfide before discharge.

[0123] The purified gas is then heated to 350-360°C, and then two-stage hydrogenation is used to convert the organic sulfur into inorganic sulfur. Two-stage zinc oxide is then used for the third desulfurization to reduce the hydrogen sulfide concentration in the gas to 0.1 mg / Nm 3 The following meets the subsequent methanogenesis needs.

[0124] 4. Methanation: The purified coal gas is preheated to 180°C through heat exchange with the methanation outlet gas, and then enters the methanation reactor 18 to remove CO and CO2. After removal, CO+CO2 is less than 10ppm. The whole process can control the generation of methane by the reaction depth of the front-end transformation.

[0125] 5. Cryogenic separation: The purified gas of 2.5-2.6MPaG after methanation enters the drying unit. The drying adopts a three-tower process to remove water to less than 1ppm through molecular sieves. After that, the gas enters the heavy hydrocarbon removal unit to remove the remaining benzene in the gas to 5mg / Nm 3 Next, CO2 can be further removed to meet the cold box 21 index.

[0126] Cryogenic separation uses MRC mixed refrigerant refrigeration process, LNG production can reach 11.2 tons / hour, methane yield ≥99%. Hydrogen-rich gas can be purified to more than 90% according to actual usage indicators. The separated nitrogen-rich tail gas can be used as TSA and drying, de-heavy hydrocarbon regeneration gas, and the rest meets the emission standards and can be directly discharged.

[0127] It is stated that the utility model uses the above embodiments to illustrate the detailed structural features of the utility model, but the utility model is not limited to the above detailed structural features, that is, it does not mean that the utility model must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the utility model, equivalent replacement of the components selected by the utility model, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the utility model.

[0128] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

[0129] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.

[0130] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A device for preparing LNG from raw coal gas and co-producing hydrogen, characterized in that: The device for preparing LNG from raw coal gas and co-producing hydrogen comprises: A pretreatment subunit, a conversion unit, a desulfurization and decarbonization unit, a methanation unit and a cryogenic separation unit connected in sequence; The pretreatment subunit includes a cooler, a tar capture device, a first compression device, a first deamination device, a first desulfurization device and a detar adsorption device connected in sequence; The conversion unit comprises a second compression device, a preheating device, a pre-conversion reactor, a humidification device and a conversion reactor connected in sequence; The desulfurization and decarbonization unit comprises a second deamination device, a second desulfurization device, an absorption tower, a hydrogenation device and a third desulfurization device connected in sequence; The methanation unit comprises a methanation reactor in sequence; The cryogenic separation unit comprises a drying device, a heavy hydrocarbon removal device and a cold box which are connected in sequence.

2. The device for preparing LNG from raw coal gas and co-producing hydrogen as claimed in claim 1, characterized in that: The material outlet of the cooler is connected to the feed inlet of the tar catching equipment; The cooler is a transverse tube cooler; the tar capture equipment includes an electric tar capture equipment.

3. The device for preparing LNG and co-producing hydrogen from raw coal gas as claimed in claim 1 or 2, characterized in that: The material outlet of the tar catching device in the pretreatment subunit is connected to the feed inlet of the first compression device; The material outlet of the first compression device is connected to the feed inlet of the first deamination device; The material outlet of the first deamination equipment is connected to the feed inlet of the first desulfurization equipment; A spray device is provided on the top of the first deamination device; The first deammoniation equipment is equipped with a circulation pump; The first compression equipment includes a screw compressor; the first deamination equipment includes a cooling deamination tower; and the first desulfurization equipment includes a wet desulfurization tower.

4. The device for preparing LNG from raw coal gas and co-producing hydrogen as claimed in claim 3, characterized in that: The material outlet of the first desulfurization equipment is connected to the feed inlet of the detarring adsorption equipment; The discharge port of the detarring adsorption device is connected to the feed port of the second compression device; The material outlet of the second compression device is connected to the material inlet of the preheating device; The material outlet of the preheating device is connected to the feed inlet of the pre-transformation reactor; The detarring adsorption equipment includes a TSA adsorption equipment; The preheating device comprises an electric heater; The pre-transformation reactor is equipped with a deoxygenated water supply device.

5. The device for preparing LNG and co-producing hydrogen from raw coal gas as claimed in claim 1 or 4, characterized in that: An electric heating device is provided between the shift reactor and the second deamination device; The second deammoniation equipment is equipped with a circulation pump.

6. The device for preparing LNG from raw coal gas and co-producing hydrogen as claimed in claim 5, characterized in that: The material outlet of the shift reactor is connected to the feed inlet of the second deamination equipment; The discharge port of the second deamination equipment is connected to the feed port of the second desulfurization equipment; The discharge port of the second desulfurization equipment is connected to the feed port of the absorption tower; A heat exchange device is arranged between the absorption tower and the hydrogenation device.

7. The device for preparing LNG and co-producing hydrogen from raw coal gas as claimed in claim 1 or 6, characterized in that: The hydrogenation equipment comprises at least two stages of hydrogenation equipment; The second desulfurization equipment includes at least two stages of desulfurization equipment.

8. The device for preparing LNG and co-producing hydrogen from raw coal gas as claimed in claim 1 or 6, characterized in that: A preheating heat exchange device is arranged between the material outlet of the third desulfurization device and the methanation reactor.

9. The device for preparing LNG from raw coal gas and co-producing hydrogen as claimed in claim 8, characterized in that: The heat medium inlet of the preheating heat exchange device is connected to the material outlet of the methanation reactor.

10. The device for preparing LNG from raw coal gas and co-producing hydrogen as claimed in claim 8, characterized in that: The heat medium outlet after heat exchange of the preheating heat exchange device is connected to the drying device; The nitrogen outlet of the cold box is connected to the regeneration gas inlet of the heavy hydrocarbon removal equipment.

Images