Process and apparatus for co-production of low-carbon methanol and liquefied natural gas from coke oven gas and carbon dioxide

Abstract

The application relates to a coke oven gas and carbon dioxide preparation low-carbon methanol co-production and liquefied natural gas method and equipment, which comprises the following steps: sequentially performing temperature swing adsorption, desulfurization and decarburization on coke oven gas by using a temperature swing adsorption device, a desulfurization device and a decarburization device to obtain a first gas. The first gas is transported to a cryogenic separation device to obtain liquefied natural gas and a second gas. Industrial tail gas is captured by using a capture device to obtain carbon dioxide gas, and the captured carbon dioxide gas and the second gas are transported to a synthesis gas compression device to obtain a third gas. The third gas is transported to a green low-carbon methanol synthesis unit to obtain green low-carbon methanol. The application does not need to newly set up pure oxygen gas making and matched air separation devices to prepare synthesis gas to provide a carbon source, so as to meet the requirement of conventional green low-carbon methanol synthesis by reacting carbon monoxide and hydrogen, and only needs to recover carbon dioxide from tail gas to realize the production of green low-carbon methanol, so that the process is simple, and the overall economic benefit of the device is better.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coking industry, and in particular to a method and equipment for producing green low-carbon methanol and co-producing liquefied natural gas from coke oven gas and carbon dioxide. BACKGROUND

[0002] In the face of the global warming trend, it is increasingly urgent to gradually reduce the emission of greenhouse gas carbon dioxide in industry.

[0003] However, most of the existing processes for producing green low-carbon methanol from coke oven gas need to newly set up pure oxygen gasification and supporting air separation devices to prepare synthesis gas to provide carbon sources to meet the requirements of conventional synthesis of green low-carbon methanol by reaction of carbon monoxide and hydrogen, which is high in cost. SUMMARY

[0004] Therefore, the present application provides a method and equipment for producing green low-carbon methanol and co-producing liquefied natural gas from coke oven gas and carbon dioxide. The present application does not need to newly set up pure oxygen gasification and supporting air separation devices to prepare synthesis gas to provide carbon sources to meet the requirements of conventional synthesis of green low-carbon methanol by reaction of carbon monoxide and hydrogen, but only needs to recover carbon dioxide from tail gas to realize the production of green low-carbon methanol, thereby directly realizing the emission reduction of carbon dioxide.

[0005] According to an aspect of the present application, a method for producing green low-carbon methanol and co-producing liquefied natural gas from coke oven gas and industrial tail gas is provided, which comprises:

[0006] using a temperature swing adsorption device, a desulfurization device and a decarbonization device to sequentially perform temperature swing adsorption, desulfurization and decarbonization on the coke oven gas to obtain a first gas;

[0007] delivering the first gas to a cryogenic separation device to process the first gas by the cryogenic separation device to obtain the liquefied natural gas and a second gas;

[0008] using a trapping device to trap the industrial tail gas to obtain carbon dioxide gas, and delivering the trapped carbon dioxide gas and the second gas to a synthesis gas compression device to obtain a third gas;

[0009] delivering the third gas to a green low-carbon methanol synthesis unit to obtain the green low-carbon methanol.

[0010] In a possible implementation, the decarbonization device adopts MDEA method for decarbonization, and the decarbonization device generates carbon dioxide gas at the same time when obtaining the first gas;

[0011] The carbon dioxide generated by the decarburization device is transported to the synthesis gas compression device, and the carbon dioxide generated by the decarburization device, the carbon dioxide captured by the capture device, and the second gas are compressed by the synthesis gas compression device to obtain the third gas.

[0012] In a possible implementation, before the coke oven gas is transported to the temperature swing adsorption device, the method further includes:

[0013] The coke oven gas is collected and stored in a gas holder, and then transported to a first pressurization device. The coke oven gas pressurized by the first pressurization device is transported to the temperature swing adsorption device. The coke oven gas treated by the temperature swing adsorption device is pressurized by a second pressurization device. The coke oven gas pressurized by the second pressurization device is transported to the desulfurization device.

[0014] In a possible implementation, the green low-carbon methanol synthesis unit includes:

[0015] The third gas is transported to a green low-carbon methanol synthesis reactor. The green low-carbon methanol is obtained by the green low-carbon methanol synthesis reactor. The green low-carbon methanol is transported to a first rectifying column. The green low-carbon methanol is rectified by the first rectifying column to obtain the green low-carbon methanol.

[0016] In a possible implementation, before the green low-carbon methanol is transported to the first rectifying column, the method further includes:

[0017] The green low-carbon methanol is separated into a circulating gas, a fourth gas, and a liquid-phase green low-carbon methanol by a first phase separation device. The fourth gas separated by the first phase separation device is recovered as purge gas by a purge gas recovery device. The circulating gas and the purge gas are pressurized by a circulating compressor and then transported to the green low-carbon methanol synthesis reactor.

[0018] In a possible implementation, before the green low-carbon methanol is transported to the first rectifying column, the method further includes:

[0019] The liquid-phase green low-carbon methanol separated by the first phase separation device is transported to a second phase separation device for separation again. The liquid-phase green low-carbon methanol separated by the second phase separation device is transported to a second rectifying column. The liquid-phase green low-carbon methanol is sequentially transported through the second rectifying column and the first rectifying column to obtain the green low-carbon methanol.

[0020] According to another aspect of the present application, a green low-carbon methanol and liquefied natural gas co-production device is provided for co-producing green low-carbon methanol and liquefied natural gas by using coke oven gas and carbon dioxide, including:

[0021] The coke oven gas pretreatment module, the synthesis gas module and the green low-carbon methanol module;

[0022] The coke oven gas pretreatment module includes the temperature swing adsorption device, the desulfurization device and the decarburization device, the gas inlet of the temperature swing adsorption device is used for inputting the coke oven gas, the gas outlet of the temperature swing adsorption device is communicated with the gas inlet of the desulfurization device, so that the coke oven gas is transported to the desulfurization device after being treated by the temperature swing adsorption device, the desulfurization device is used for desulfurization treatment, the gas outlet of the desulfurization device is communicated with the gas inlet of the decarburization device, so that the coke oven gas is transported to the decarburization device after being desulfurized by the desulfurization device, and the decarburization device is used for decarburization treatment to obtain the first gas.

[0023] The synthesis gas module includes the cryogenic separation device, the trapping device and the synthesis gas compression device, the first gas outlet of the decarburization device is communicated with the feed inlet of the cryogenic separation device, so that the cryogenic separation device separates the first gas into the second gas and the liquefied natural gas, the gas outlet of the trapping device and the gas outlet of the cryogenic separation device are both communicated with the first gas inlet and the second gas inlet of the synthesis gas compression device, so that the second gas and the carbon dioxide gas trapped by the trapping device are transported to the synthesis gas compression device, and the synthesis gas compression device is used for synthesis compression of the second gas and the carbon dioxide gas.

[0024] The green low-carbon methanol module includes the green low-carbon methanol synthesis reactor, the feed inlet of the green low-carbon methanol synthesis reactor is communicated with the gas outlet of the synthesis gas compression device, so that the third gas is transported to the green low-carbon methanol synthesis reactor, and the green low-carbon methanol synthesis reactor is used for treating the third gas to generate green low-carbon methanol.

[0025] In a possible implementation, the decarburization device is communicated with the third gas inlet of the synthesis gas compression device, and is used for inputting the carbon dioxide gas discharged by the decarburization device into the synthesis compression device.

[0026] In a possible implementation, the coke oven gas pretreatment module further includes the gas tank, the first pressurizing device and the second pressurizing device.

[0027] The gas tank is used for collecting and storing the coke oven gas, the gas outlet of the gas tank is communicated with the gas inlet of the first pressurizing device, the gas outlet of the first pressurizing device is communicated with the gas inlet of the temperature swing adsorption device, the gas outlet of the temperature swing adsorption device is communicated with the gas inlet of the second pressurizing device, and the gas outlet of the second pressurizing device is communicated with the gas inlet of the desulfurization device.

[0028] In a possible implementation, the green low-carbon methanol module further comprises the first phase separation device, the circulating compressor, the purge gas recovery device, the second phase separation device, the first rectifying tower and the second rectifying tower.

[0029] The feed inlet of the green low-carbon methanol synthesis reactor is communicated with the discharge outlet of the synthesis gas compression device, the third gas is synthesized into the crude green low-carbon methanol, the discharge outlet of the green low-carbon methanol synthesis device is communicated with the first phase separation device, the first gas inlet of the circulating compressor is communicated with the gas phase outlet of the first phase separation device, the gas outlet of the purge gas is communicated with the second gas inlet of the circulating compressor, the gas outlet of the circulating compressor is communicated with the feed inlet of the green low-carbon methanol synthesis reactor, the liquid phase outlet of the first phase separation device is communicated with the second phase separation device, the liquid phase outlet of the second phase separation device is communicated with the second rectifying tower, the liquid phase outlet of the second rectifying tower is communicated with the first rectifying tower, and the first rectifying tower obtains the green low-carbon methanol.

[0030] The coke oven gas and carbon dioxide are used to produce low-carbon methanol and co-produced liquefied natural gas, the benzene, naphthalene and tar in the coke oven gas are separated by TSA (temperature swing adsorption), the sulfides in the coke oven gas are removed by desulfurization, the carbon dioxide in the coke oven gas is removed by decarburization, the first gas is obtained by TSA, desulfurization and decarburization, the liquefied natural gas and the second gas rich in hydrogen and carbon monoxide are extracted by cryogenic separation, and the hydrogen, methane and carbon monoxide in the coke oven gas are efficiently utilized in stages. The second gas and the carbon dioxide captured from the industrial tail gas are transported to a green low-carbon methanol synthesis unit as synthesis gas to prepare green low-carbon methanol, the carbon dioxide in the industrial tail gas is directly used as a synthesis raw material gas, the carbon dioxide emission is reduced, the carbon dioxide in the coke oven gas is recycled, and the carbon dioxide is used as a basic raw material for green low-carbon methanol synthesis. In the green low-carbon methanol synthesis unit, the synthesis reaction mainly uses carbon dioxide and hydrogen, and a small amount of carbon monoxide and hydrogen is used to prepare green low-carbon methanol. The present application does not need to newly set up a pure oxygen gas making device and a supporting air separation device to prepare synthesis gas to provide a carbon source to meet the requirement of conventional green low-carbon methanol synthesis using carbon monoxide and hydrogen, and only needs to recover carbon dioxide from the tail gas to realize the production of green low-carbon methanol, so that the process is simple and the overall economic benefit of the device is good.

[0031] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the drawings.

[0032] Figure 1A process flow diagram of a method for producing low-carbon methanol and co-producing liquefied natural gas from coke oven gas and carbon dioxide according to an embodiment of the present application is shown.

[0033] Figure 2 A process flow diagram of a device for producing green low-carbon methanol and co-producing liquefied natural gas according to an embodiment of the present application is shown.

[0034] Figure 3 A process flow diagram of a green low-carbon methanol synthesis unit according to an embodiment of the present application is shown.

[0035] Various exemplary embodiments, features, and aspects of the present application will be described in detail, with reference to the accompanying drawings. The same reference numbers in different drawings denote the same or similar elements throughout the drawings. Although various aspects of the embodiments are illustrated in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0036] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application or simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0037] In addition, the terms "first", "second", are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0038] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0039] In addition, in order to better illustrate the present application, a large number of specific details are given in the specific embodiments below. Those skilled in the art should understand that the present application can also be implemented without some specific details. In some examples, methods, means, elements and circuits that are well known to those skilled in the art are not described in detail, in order to highlight the main ideas of the present application.

[0040] Figure 1 A process flow diagram of a method for producing low-carbon methanol and co-producing liquefied natural gas from coke oven gas and carbon dioxide according to an embodiment of the present application is shown. As shown in FIG. 1, the method comprises the following steps:Figure 1 As shown, the method comprises: step S100, using a temperature swing adsorption device, a desulfurization device and a decarburization device to sequentially perform temperature swing adsorption, desulfurization and decarburization on the coke oven gas to obtain a first gas. Step S200, the first gas is transported to a cryogenic separation device to obtain liquefied natural gas and a second gas. Step S300, using a capture device to capture industrial tail gas to obtain carbon dioxide gas, and transporting the captured carbon dioxide gas and the second gas to a synthesis gas compression device to obtain a third gas. Step S400, the third gas is transported to a green low-carbon methanol synthesis unit to obtain green low-carbon methanol.

[0041] The coke oven gas and carbon dioxide to low-carbon methanol co-production liquefied natural gas method of the embodiment of the application, by TSA temperature swing adsorption on the coke oven gas, the benzene, naphthalene and tar in the coke oven gas are separated, then the coke oven gas is desulfurized to remove sulfides in the coke oven gas, and then the coke oven gas is decarburized to remove carbon dioxide in the coke oven gas. The coke oven gas is obtained by temperature swing adsorption, desulfurization and decarburization. The first gas is cryogenically separated to extract liquefied natural gas and a second gas rich in hydrogen and carbon monoxide. Compared with the traditional coke oven gas to methanol method, the application has the following advantages: efficient hierarchical utilization of hydrogen, methane and carbon monoxide in the coke oven gas is realized. The second gas and the carbon dioxide captured from the industrial tail gas by the capture device 220 are transported together as synthesis gas to the green low-carbon methanol synthesis unit to prepare green low-carbon methanol. The carbon dioxide in the industrial tail gas is used as a synthesis raw material gas, directly realizing carbon dioxide emission reduction, realizing resource utilization of carbon dioxide in the coke oven gas, and serving as a basic raw material for green low-carbon methanol synthesis. In the green low-carbon methanol synthesis unit, the synthesis reaction is mainly carbon dioxide and hydrogen reaction, and a small amount of carbon monoxide and hydrogen reaction is used to prepare green low-carbon methanol. The application does not need to newly set up a pure oxygen gas making device and a matching air separation device to prepare synthesis gas to provide a carbon source to meet the requirements of conventional carbon monoxide and hydrogen reaction synthesis of green low-carbon methanol. Only carbon dioxide needs to be recovered from the tail gas to realize the production of green low-carbon methanol, the process is simple, and the overall economic benefit of the device is good.

[0042] In a possible implementation, the decarburization device 160 adopts the MDEA method for decarburization, and the decarburization device 160 obtains the first gas while generating carbon dioxide gas. The carbon dioxide generated by the decarburization device 160 is transported to the synthesis gas compression device 230, and the carbon dioxide generated by the decarburization device 160, the carbon dioxide captured by the capture device 220, and the second gas are obtained by the synthesis gas compression device 230 to obtain the third gas. MDEA is also known as N-methyldiethanolamine, and the MDEA decarburization technology is to use MDEA aqueous solution to absorb carbon dioxide in the gas at high pressure and normal temperature, and the MDEA aqueous solution after absorbing carbon dioxide is heated and decompressed to release carbon dioxide, and the released carbon dioxide is transported to the synthesis gas compression device 230 and is used as a carbon source for green low-carbon methanol synthesis together with the carbon dioxide captured by the capture device 220.

[0043] In a possible implementation, before the coke oven gas is transported to the temperature swing adsorption device 130, the coke oven gas is collected and stored by using the gas tank 110, and then the stored coke oven gas is transported to the first pressurizing device 120, the coke oven gas pressurized by the first pressurizing device 120 is transported to the temperature swing adsorption device 130, the coke oven gas processed by the temperature swing adsorption device is pressurized by using the second pressurizing device 140, and the coke oven gas pressurized by the second pressurizing device 140 is transported to the desulfurization device 150. By arranging the first pressurizing device 120 and the second pressurizing device 140, the pressure required for the coke oven gas to reach the temperature swing adsorption and the MDEA decarburization is reached, and the reaction is more sufficient.

[0044] In a possible implementation, the green low-carbon methanol synthesis unit includes: the third gas is transported to the green low-carbon methanol synthesis reactor 310, the crude green low-carbon methanol is obtained by the green low-carbon methanol synthesis reactor 310, the crude green low-carbon methanol is transported to the first rectifying tower 361, the crude green low-carbon methanol is rectified by the first rectifying tower 361, and the green low-carbon methanol is obtained. The overall process is relatively simple, and the production cost is effectively reduced.

[0045] In a possible implementation, before being delivered to the first rectifying tower 361, the crude green low-carbon methanol further comprises: the crude green low-carbon methanol is subjected to gas-liquid separation by the first phase separation device 320, and the circulating gas, the fourth gas and the liquid-phase crude green low-carbon methanol are separated out; the fourth gas separated out by the first phase separation device 320 is obtained by the purge gas recovery device 330; and the circulating gas and the purge gas are pressurized by the circulating compressor 340 and then delivered to the green low-carbon methanol synthesis reactor 310. By arranging the first phase separation device 320, the purge gas recovery device 330 and the circulating compressor 340, the purge gas and the circulating gas can re-enter the green low-carbon methanol synthesis reactor 310 to participate in the reaction, thereby reducing the production cost. The fourth gas comprises the purge gas and the tail gas, and the purge gas recovery device 330 separates the purge gas and the tail gas; the tail gas without pollution can be directly discharged. The purge gas of the methanol synthesis is rich in hydrogen, and the purge gas recovery device 330 greatly improves the utilization value of the coke oven gas and promotes the emission reduction of carbon dioxide.

[0046] In a possible implementation, before being delivered to the first rectifying tower 361, the crude green low-carbon methanol further comprises: the liquid-phase crude green low-carbon methanol separated out by the first phase separation device 320 is delivered to the second phase separation device 350 to be separated again, the liquid-phase crude green low-carbon methanol separated out by the second phase separation device 350 is delivered to the second rectifying tower 362, and the liquid-phase crude green low-carbon methanol sequentially passes through the second rectifying tower 362 and the first rectifying tower 361 to obtain the green low-carbon methanol. By separating the tail gas in the liquid-phase crude green low-carbon methanol again before rectifying the liquid-phase crude green low-carbon methanol.

[0047] According to another aspect of the present application, as Figure 2As shown, a green low-carbon methanol co-production liquefied natural gas equipment is provided for producing low-carbon methanol co-production liquefied natural gas from coke oven gas and carbon dioxide according to the above method, which comprises a coke oven gas pretreatment module, a synthesis gas module and a green low-carbon methanol production module. The coke oven gas pretreatment module comprises a temperature swing adsorption device 130, a desulfurization device 150 and a decarbonization device 160. The gas inlet of the temperature swing adsorption device 130 is used to introduce coke oven gas. The gas outlet of the temperature swing adsorption device 130 is communicated with the gas inlet of the desulfurization device 150 to obtain a first gas. The gas outlet of the desulfurization device 150 is communicated with the gas inlet of the decarbonization device 160. The synthesis gas module comprises a cryogenic separation device 210, a trapping device 220 and a synthesis gas compression device 230. The gas outlet of the decarbonization device 160 is communicated with the feed inlet of the cryogenic separation device 210, and the first gas is separated into a second gas and liquefied natural gas. The gas outlet of the trapping device 220 and the gas outlet of the cryogenic separation device 210 are respectively communicated with the first gas inlet and the second gas inlet of the synthesis gas compression device 230. The first gas inlet and the second gas inlet of the synthesis gas compression device 230 are respectively used to introduce the second gas and the carbon dioxide trapped by the trapping device 220. The green low-carbon methanol production module comprises a green low-carbon methanol synthesis reactor 310. The feed inlet of the green low-carbon methanol synthesis reactor 310 is communicated with the gas outlet of the synthesis gas compression device 230 to obtain green low-carbon methanol.

[0048] The equipment of the embodiment of the present application realizes efficient hierarchical utilization of hydrogen, methane and carbon monoxide in coke oven gas by performing TSA temperature swing adsorption on the coke oven gas to separate benzene, naphthalene and tar in the coke oven gas, then performing desulfurization on the coke oven gas to remove sulfides in the coke oven gas, and then performing decarbonization on the coke oven gas to remove carbon dioxide in the coke oven gas. The coke oven gas is subjected to temperature swing adsorption, desulfurization and decarbonization to obtain a first gas. The first gas is subjected to cryogenic separation to extract liquefied natural gas and a second gas rich in hydrogen and carbon monoxide. The second gas and the carbon dioxide trapped from the industrial tail gas by the trapping device 220 are transported together as synthesis gas to a green low-carbon methanol synthesis unit to prepare green low-carbon methanol. The carbon dioxide in the industrial tail gas is used as a synthesis raw material gas, directly realizing carbon dioxide emission reduction, realizing resource utilization of carbon dioxide in the coke oven gas, and serving as a basic raw material for green low-carbon methanol synthesis. In the green low-carbon methanol synthesis unit, the synthesis reaction is mainly carbon dioxide and hydrogen reaction, and a small amount of carbon monoxide and hydrogen reaction is also used to prepare green low-carbon methanol. The present application does not need to newly set up a pure oxygen gas making device and a matching air separation device to prepare synthesis gas to provide a carbon source to meet the requirement of conventional green low-carbon methanol synthesis by carbon monoxide and hydrogen reaction. The production of green low-carbon methanol can be realized only by recovering carbon dioxide from the tail gas, the process is simple, the overall economic benefit of the device is good, efficient hierarchical utilization of hydrogen, methane and carbon monoxide in coke oven gas is realized, resource utilization of carbon dioxide in coke oven gas is realized, and the carbon dioxide serves as a basic raw material for green low-carbon methanol synthesis.

[0049] It should be noted that the cryogenic separation device 210 can be implemented by using the common technical means of those skilled in the art, and thus will not be described here.

[0050] In a possible implementation, the carbon discharge port of the decarburization device 160 is in communication with the third gas inlet of the synthesis gas compression device 230, for introducing the carbon dioxide obtained by the decarburization device 160. The synthesis gas compression device 230 synthesizes the second gas rich in hydrogen and carbon monoxide, the carbon dioxide obtained by the decarburization device 160, and the carbon dioxide obtained by the capture device 220 into synthesis gas, and delivers the synthesis gas to the green low-carbon methanol preparation module to prepare green low-carbon methanol.

[0051] In a possible implementation, the coke oven gas pretreatment module further includes a gas tank 110, a first pressurizing device 120, and a second pressurizing device 140. The gas tank 110 is used to collect and store the coke oven gas. The gas outlet of the gas tank 110 is in communication with the gas inlet of the first pressurizing device 120. The gas outlet of the first pressurizing device 120 is in communication with the gas inlet of the temperature swing adsorption device 130. The gas outlet of the temperature swing adsorption device 130 is in communication with the gas inlet of the second pressurizing device 140. The gas outlet of the second pressurizing device 140 is in communication with the gas inlet of the desulfurization device 150. The gas inlet of the gas tank 110 is used to introduce the coke oven gas. The coke oven gas sequentially passes through the first pressurizing device, the temperature swing adsorption device 130, the second pressurizing device, the desulfurization device 150, and the decarburization device 160 to obtain the first gas and the carbon dioxide gas. By sequentially connecting the first pressurizing device, the temperature swing adsorption device 130, the second pressurizing device, the desulfurization device 150, and the decarburization device 160, the coke oven gas is subjected to temperature swing adsorption, desulfurization, and decarburization to obtain the first gas and the carbon dioxide, and the overall structure is relatively simple, effectively reducing the production cost.

[0052] In a possible implementation, the green low-carbon methanol module comprises a green low-carbon methanol synthesis reactor 310, a first phase separation device 320, a circulation compressor 340, a purge gas recovery device 330, a second phase separation device 350, a second rectifying column 362, and a first rectifying column 361. The feed inlet of the green low-carbon methanol synthesis reactor 310 is in communication with the outlet of the syngas compression device 230, the third gas is synthesized into crude green low-carbon methanol, the outlet of the green low-carbon methanol synthesis device is in communication with the first phase separation device 320, the first gas inlet of the circulation compressor 340 and the gas inlet of the purge gas recovery device 330 are both in communication with the gas phase outlet of the first phase separation device 320, the gas outlet of the purge gas is in communication with the second gas inlet of the circulation compressor 340, the gas outlet of the circulation compressor 340 is in communication with the feed inlet of the green low-carbon methanol synthesis reactor 310, the liquid phase outlet of the first phase separation device 320 is in communication with the second phase separation device 350, the liquid phase outlet of the second phase separation device 350 is in communication with the second rectifying column 362, the liquid phase outlet of the second rectifying column 362 is in communication with the first rectifying column 361, and the first rectifying column 361 obtains green low-carbon methanol. By arranging the first phase separation device 320, the purge gas recovery device 330, and the circulation compressor 340, the purge gas and the circulation gas can re-enter the green low-carbon methanol synthesis reactor 310 to participate in the reaction, thereby reducing the production cost. The fourth gas comprises the purge gas and the tail gas, the purge gas recovery device 330 separates the purge gas and the tail gas, and the pollution-free tail gas can be directly discharged. The first rectifying column 361 obtains the green low-carbon methanol product in the gas phase and the water and byproducts in the liquid phase through phase separation.

[0053] Here, it needs to be explained that the first rectifying column 361 and the second rectifying column 362 are both provided with reflux devices, which further improve the precision of the prepared green low-carbon methanol.

[0054] The above has described the embodiments of the present application, and the above description is exemplary, is not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A method for producing low-carbon methanol and liquefied natural gas by co-producing coke oven gas and carbon dioxide, characterized in that: Used to convert coke oven gas and industrial tail gas into green, low-carbon methanol and liquefied natural gas, including: Using a temperature swing adsorption device, a desulfurization device, and a decarbonization device to sequentially perform temperature swing adsorption, desulfurization, and decarbonization on the coke oven gas to obtain a first gas; transporting the first gas to a cryogenic separation device, and processing the first gas in the cryogenic separation device to obtain the liquefied natural gas and the second gas; Using a capture device to capture the industrial tail gas to obtain carbon dioxide gas, and transporting the captured carbon dioxide gas and the second gas to a synthesis gas compression device to obtain a third gas; transporting the third gas to a green low-carbon methanol synthesis unit to obtain the green low-carbon methanol; Before the coke oven gas is transported to the temperature swing adsorption device, the method further comprises: Using a gas cabinet to collect and store the coke oven gas, then transporting the stored coke oven gas to a first pressurizing device, transporting the coke oven gas pressurized by the first pressurizing device to the temperature swing adsorption device, using a second pressurizing device to pressurize the coke oven gas adsorbed by the temperature swing adsorption device, and transporting the coke oven gas pressurized by the second pressurizing device to the desulfurization device; When the decarbonization device obtains the first gas, it also produces carbon dioxide gas; the carbon dioxide produced by the decarbonization device is transported to the synthesis gas compression device; The green low-carbon methanol synthesis unit comprises: the third gas is transported to a green low-carbon methanol synthesis reactor, crude green low-carbon methanol is obtained through the green low-carbon methanol synthesis reactor, the crude green low-carbon methanol is transported to a first distillation tower, and the first distillation tower distills the crude green low-carbon methanol to obtain the green low-carbon methanol; Before the crude green low-carbon methanol is transported to the first distillation tower, the process further includes: performing gas-liquid separation on the crude green low-carbon methanol by a first phase separation device to separate circulating gas, a fourth gas and liquid-phase crude green low-carbon methanol, and transporting the liquid-phase crude green low-carbon methanol separated by the first phase separation device to a second phase separation device for further separation; obtaining a purge gas from a purge gas recovery device by using the fourth gas separated by the first phase separation device, and pressurizing the circulating gas and the purge gas by a circulating compressor and then transporting them to the green low-carbon methanol synthesis reactor; The liquid phase crude green low-carbon methanol separated by the second phase separation device is transported to the second distillation tower; The first distillation tower and the second distillation tower are both provided with a reflux device to further improve the accuracy of the prepared green and low-carbon methanol.

2. The method according to claim 1, characterized in that The decarbonization device adopts MDEA method for decarbonization, and the carbon dioxide generated by the decarbonization device, the carbon dioxide captured by the capture device and the second gas are passed through the synthesis gas compression device to obtain the third gas.

3. A green low-carbon methanol co-production liquefied natural gas equipment, characterized by: The method for producing low-carbon methanol from coke oven gas and carbon dioxide and co-producing liquefied natural gas using the method according to any one of claims 1 to 2 comprises: Coke oven gas pretreatment module, synthesis gas module and green low-carbon methanol production module; The coke oven gas pretreatment module includes the temperature swing adsorption device, the desulfurization device and the decarbonization device. The air inlet of the temperature swing adsorption device is used to introduce the coke oven gas. The air outlet of the temperature swing adsorption device is connected to the air inlet of the desulfurization device, so that the coke oven gas is transported to the desulfurization device after being treated by the temperature swing adsorption device, and the desulfurization device performs desulfurization treatment. The air outlet of the desulfurization device is connected to the air inlet of the decarbonization device, so that the coke oven gas is transported to the decarbonization device after being desulfurized by the desulfurization device, and the decarbonization device performs decarbonization treatment to obtain the first gas. The synthesis gas module includes the cryogenic separation device, the capture device and the synthesis gas compression device. The first gas outlet of the decarbonization device is connected to the feed port of the cryogenic separation device, so that the cryogenic separation device separates the first gas into the second gas and the liquefied natural gas. The gas outlet of the capture device and the gas outlet of the cryogenic separation device are both connected to the first gas inlet and the second gas inlet of the synthesis gas compression device, so that the second gas and the carbon dioxide gas captured by the capture device are transported to the synthesis gas compression device, and the synthesis gas compression device synthesizes and compresses the second gas and the carbon dioxide gas. The green and low-carbon methanol module includes the green and low-carbon methanol synthesis reactor, and the feed port of the green and low-carbon methanol synthesis reactor is connected to the gas outlet of the synthesis gas compression device so that the third gas is transported to the green and low-carbon methanol synthesis reactor, and the third gas is processed by the green and low-carbon methanol synthesis reactor to generate green and low-carbon methanol.

4. The device according to claim 3, characterized in that The decarbonization device is connected to the third air inlet of the synthesis gas compression device, and is used to input the carbon dioxide gas discharged from the decarbonization device into the synthesis compression device.

5. The device according to claim 4, characterized in that The coke oven gas pretreatment module further includes the gas cabinet, the first pressurizing device and the second pressurizing device; The gas holder is used to collect and store the coke oven gas. The gas outlet of the gas holder is connected to the air inlet of the first pressurizing device, the gas outlet of the first pressurizing device is connected to the air inlet of the temperature-swing adsorption device, the gas outlet of the temperature-swing adsorption device is connected to the air inlet of the second pressurizing device, and the gas outlet of the second pressurizing device is connected to the air inlet of the desulfurization device.

6. The device according to claim 5, characterized in that The green low-carbon methanol production module further includes the first phase separation device, the circulating compressor, the purge gas recovery device, and the second phase separation device; The feed port of the green and low-carbon methanol synthesis reactor is connected to the discharge port of the synthesis gas compression device, and the third gas is synthesized into the crude green and low-carbon methanol. The discharge port of the green and low-carbon methanol synthesis device is connected to the first phase separation device, and the first air inlet of the circulation compressor and the air inlet of the relaxation gas recovery device are both connected to the gas phase outlet of the first phase separation device. The outlet of the relaxation gas is connected to the second air inlet of the circulation compressor, and the outlet of the circulation compressor is connected to the feed port of the green and low-carbon methanol synthesis reactor. The liquid phase outlet of the first phase separation device is connected to the second phase separation device, and the liquid phase outlet of the second phase separation device is connected to the second distillation tower. The liquid phase outlet of the second distillation tower is connected to the first distillation tower, and the first distillation tower obtains the green and low-carbon methanol.

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