Device for preparing liquefied natural gas through carbon neutralization

Abstract

The embodiment of the utility model provides a device for preparing liquefied natural gas through carbon neutralization. The device comprises a carbon dioxide storage tank, a carbon dioxide pump and a gasifier, wherein liquid carbon dioxide is stored in the carbon dioxide storage tank, the carbon dioxide storage tank is communicated with a gas inlet of the carbon dioxide pump, a gas outlet of the carbon dioxide pump is communicated with an inlet of the vaporizer through a pipeline, the vaporizing chamber converts the liquid carbon dioxide into gaseous carbon dioxide, and an outlet of the vaporizer is communicated with the liquefied natural gas fine desulfurization assembly. Carbon dioxide enters the liquefied natural gas fine desulfurization assembly from the gasification chamber to supplement carbon dioxide, so that the content of carbon dioxide in coal gas is increased, and the utilization rate of raw material gas is further increased.

Description

Technical Field

[0001] This application relates to the technical field of natural gas production, and particularly to a device for carbon-neutral production of liquefied natural gas. Background Art

[0002] Since the LNG device completed the feeding and commissioning test, it has been able to stably produce high-quality qualified liquefied natural gas (LNG) products.

[0003] In the process of natural gas production, due to the low carbon dioxide content in the raw material coke oven gas, the methanation device cannot consume all the raw material gases during the reaction. The device by-produces about 15000 Nm / h of nitrogen and hydrogen gas, which is directly used for boiler combustion power generation and cannot be effectively utilized, resulting in a large amount of resource waste and economic losses. Utility Model Content

[0004] The embodiments of this application provide a device for carbon-neutral production of liquefied natural gas to solve the problem that the carbon dioxide content in the current raw material coke oven gas is low and the methanation device cannot consume all the raw material gases during the reaction.

[0005] The embodiments of this application provide a device for carbon-neutral production of liquefied natural gas, including a carbon dioxide storage tank, a carbon dioxide pump and a vaporizer;

[0006] The carbon dioxide storage tank is communicated with the intake port of the carbon dioxide pump, the outlet of the carbon dioxide pump is communicated with the inlet of the vaporizer through a pipeline, and the outlet of the vaporizer is communicated with the liquefied natural gas fine desulfurization component.

[0007] In a feasible implementation manner, the device for carbon-neutral production of liquefied natural gas further includes a low-pressure steam pipeline and a condensate pipeline;

[0008] The low-pressure steam pipeline is communicated with the inlet of the heating pipeline of the vaporizer, the condensate pipeline is communicated with the inlet of the heating pipeline of the vaporizer, and the low-pressure steam in the low-pressure steam pipeline heats the vaporizer.

[0009] In a feasible implementation manner, there are multiple carbon dioxide storage tanks, and multiple carbon dioxide storage tanks are all communicated with the main pipeline, and the main pipeline is communicated with the intake port.

[0010] In a feasible implementation manner, the device for carbon-neutral production of liquefied natural gas further includes a plurality of control valves, and each carbon dioxide storage tank is provided with the control valve.

[0011] In a feasible implementation manner, the pipeline between the carbon dioxide storage tank and the vaporizer is provided with the control valve.

[0012] In a feasible implementation manner, the device for carbon-neutral production of liquefied natural gas further includes a flow regulating valve, and the flow regulating valve is arranged on the pipeline between the vaporizer and the liquefied natural gas fine desulfurization assembly.

[0013] The embodiment of the present application provides a device for carbon-neutral production of liquefied natural gas, including a carbon dioxide storage tank, a carbon dioxide pump and a vaporizer; wherein, liquid carbon dioxide is stored in the carbon dioxide storage tank, the carbon dioxide storage tank is communicated with the intake port of the carbon dioxide pump, the outlet of the carbon dioxide pump is communicated with the inlet of the vaporizer through a pipeline, the vaporization chamber converts liquid carbon dioxide into gaseous carbon dioxide, the outlet of the vaporizer is communicated with the liquefied natural gas fine desulfurization assembly, and carbon dioxide enters the liquefied natural gas fine desulfurization assembly from the vaporization chamber to supplement carbon dioxide, increase the content of carbon dioxide in the coal gas, and thus improve the utilization rate of the raw material gas. Description of the Drawings

[0014] The drawings described herein are used to provide a further understanding of the present utility model, and constitute a part of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present utility model.

[0015] In the drawings:

[0016] Figure 1 is a schematic diagram of the device for carbon-neutral production of liquefied natural gas provided by an embodiment of the present application;

[0017] Description of the Reference Numerals:

[0018] 100 - carbon dioxide storage tank; 200 - carbon dioxide pump; 300 - vaporizer; 400 - low-pressure steam pipeline; 500 - condensate pipeline; 600 - control valve; 700 - flow regulating valve. Detailed Embodiments

[0019] In order to enable those skilled in the art to better understand the technical solutions in the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0020] In the description of the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0021] In the present application, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0022] Since the LNG device has completed the commissioning test run, it can stably produce high-quality qualified liquefied natural gas (LNG) products.

[0023] During the natural gas production process, due to the low carbon dioxide content in the raw material coke oven gas, the methanation device cannot consume all the raw material gases during the reaction. The device by-produces about 15,000 Nm / h of nitrogen-hydrogen gas, which is directly used for boiler combustion power generation and cannot be effectively utilized, resulting in a large amount of resource waste and economic losses.

[0024] In order to solve the problem that the carbon dioxide content in the current raw material coke oven gas is low and the methanation device cannot consume all the raw material gases during the reaction, the embodiments of the present application provide a device for carbon-neutral production of liquefied natural gas. The following will detail the solution provided by the embodiments of the present application with reference to the accompanying drawings of the specification.

[0025] Figure 1 It is a schematic diagram of a device for carbon-neutral production of liquefied natural gas provided by an embodiment of the present application.

[0026] The embodiments of the present application provide a device for carbon-neutral production of liquefied natural gas, including a carbon dioxide storage tank 100, a carbon dioxide pump 200, and a vaporizer 300. Among them, the carbon dioxide storage tank 100 stores liquid carbon dioxide. The carbon dioxide storage tank 100 is communicated with the intake port of the carbon dioxide pump 200. The outlet of the carbon dioxide pump 200 is communicated with the inlet of the vaporizer 300 through a pipeline. The vaporization chamber converts the liquid carbon dioxide into gaseous carbon dioxide. The outlet of the vaporizer 300 is communicated with the liquefied natural gas fine desulfurization component. Carbon dioxide enters the liquefied natural gas fine desulfurization component from the vaporization chamber to supplement carbon dioxide, increase the carbon dioxide content in the gas, and thus improve the utilization rate of the raw material gas.

[0027] Specifically, by injecting carbon dioxide, the nitrogen gas by-produced by the device undergoes a methanation reaction and finally produces liquefied natural gas products, avoiding waste of resources and bringing good economic benefits. The consumption of carbon dioxide and hydrogen reaches 1650 Nm³ / h and 6663 Nm³ / h respectively, and the annual output of liquid natural gas can be increased by about 12400 t, achieving energy conservation, emission reduction and sustainable high-quality development of green and low-carbon.

[0028] Continue to refer to Figure 1 As shown, in some examples, the device for producing liquefied natural gas with carbon neutralization further includes a low-pressure steam pipeline 400 and a condensate pipeline 500. The low-pressure steam pipeline 400 is connected to the inlet of the heating pipeline of the vaporizer 300, and the condensate pipeline 500 is connected to the inlet of the heating pipeline of the vaporizer 300. The low-pressure steam in the low-pressure steam pipeline 400 heats the vaporizer 300, so that the liquid carbon dioxide in the carbon dioxide storage tank 100 is converted into gaseous carbon dioxide.

[0029] Continue to refer to Figure 1 As shown, in some examples, there are multiple carbon dioxide storage tanks 100 in the device, and the multiple carbon dioxide storage tanks 100 are all connected to the main pipeline, and the main pipeline is connected to the air inlet.

[0030] In some other examples, the device for producing liquefied natural gas with carbon neutralization further includes a plurality of control valves 600. Each carbon dioxide storage tank 100 is provided with a control valve 600, and the control valve 600 is used to control the amount of carbon dioxide flowing out of the carbon dioxide storage tank 100.

[0031] Similarly, a control valve 600 is provided on the pipeline between the carbon dioxide storage tank 100 and the vaporizer 300. By opening and closing the control valve 600, the flow rate of carbon dioxide flowing to the vaporizer 300 can be controlled.

[0032] Continue to refer to Figure 1 As shown, the device for producing liquefied natural gas with carbon neutralization further includes a flow regulating valve 700, and the flow regulating valve 700 is arranged on the pipeline between the vaporizer 300 and the liquefied natural gas fine desulfurization component.

[0033] Liquid carbon dioxide is transported to the site by a tank truck and unloaded into the carbon dioxide storage tank 100 through the unloading crane pipe N-33131. The liquid carbon dioxide is pressurized to 3.2 MPaG by the carbon dioxide pump 200 and then sent to the vaporizer 300 for gasification. The maximum carbon supplementation amount of the vaporizer 300 is 1650 Nm 3 / h. The gasified carbon dioxide is precisely controlled by the flow regulating valve 700 to supplement the flow rate into the liquefied natural gas production system, and by comparing with the flowmeter before the vaporizer 300, it is ensured that there is no deviation in the carbon supplementation amount. In addition, the pressure of carbon dioxide at the outlet of the vaporizer 300 is about 3.1 MPaG. After being reduced in pressure to about 2.8 MPaG by the flow regulating valve 700, it is supplemented into the liquefied natural gas production system before the medium-temperature desulfurization tower in the fine desulfurization section, and after passing through the hydrodesulfurization unit, it is sent to the methanation unit to participate in the methanation reaction.

[0034] In addition, in some examples, the device for carbon-neutral production of liquefied natural gas further includes a main board fin heat exchanger, a dehydrogenation tower, a dehydrogenation tower reflux drum, a dehydrogenation tower top condenser, a denitrification tower, a denitrification tower reflux drum, a denitrification tower top condenser, a denitrification tower reboiler, refrigerant flash drums (upper, middle, and lower), a refrigerant separation tank, and a subcooler connected in sequence. The purified raw material gas enters the cold box liquefaction heat exchanger and is cooled to a certain temperature by the refluxing mixed refrigerant and then exits the liquefaction heat exchanger and enters the bottom of the dehydrogenation rectification tower to participate in rectification.

[0035] In the dehydrogenation rectification tower, the rising gas contacts and transfers heat and mass with the flowing-down liquid on the structured packing. The hydrogen-rich tail gas is obtained at the top of the dehydrogenation rectification tower and enters the dehydrogenation tower condenser to exchange heat with liquid nitrogen. The liquid nitrogen evaporates and part of the hydrogen-rich tail gas is liquefied as the reflux liquid of the dehydrogenation rectification tower. After separation in the dehydrogenation tower reflux drum, the unliquefied part of the hydrogen-rich tail gas returns to the subcooler and the liquefaction heat exchanger, is reheated, and then exits the cold box to the user pipeline network; the methane-rich liquid is obtained at the bottom of the dehydrogenation tower and is sent to the middle of the denitrification rectification tower to participate in rectification. A condenser is provided at the top of the denitrification rectification tower, with throttled liquid nitrogen as the cold source; an evaporator is provided at the bottom of the denitrification rectification tower, using the gas-phase refrigerant after heat exchange and temperature reduction as the heat source to evaporate LNG as the rising gas. In the denitrification rectification tower, the rising gas and the reflux liquid transfer heat and mass on the surface of the structured packing. During the rising process of the gas, the nitrogen content gradually increases and the methane content gradually decreases. The nitrogen-rich tail gas is obtained at the top of the denitrification rectification tower and enters the condenser to exchange heat with liquid nitrogen. The liquid nitrogen evaporates and part of the nitrogen-rich tail gas is liquefied as the reflux liquid of the denitrification rectification tower. The uncondensed nitrogen-rich tail gas is led out and returns to the subcooler and the liquefaction heat exchanger, is reheated to room temperature, and then exits the cold box to the user pipeline network. LNG is obtained at the bottom of the denitrification rectification tower, sent to the liquefaction heat exchanger for subcooling, and after throttling and pressure reduction by the subsequent owner's throttle valve, it is sent out of the boundary area to the user LNG storage tank.

[0036] It is easy to understand that those skilled in the art can combine, split, and recombine the embodiments of the present application based on several embodiments provided in the present application to obtain other embodiments, and these embodiments do not exceed the protection scope of the present application.

[0037] In the above specific embodiments, the objectives, technical solutions, and beneficial effects of the embodiments of the present application have been further described in detail. It should be understood that the above are only specific embodiments of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A carbon-neutral liquefied natural gas production device, characterized in that: It comprises a carbon dioxide storage tank (100), a carbon dioxide pump (200) and a gasifier (300); The carbon dioxide storage tank (100) is connected to the air inlet of the carbon dioxide pump (200), the air outlet of the carbon dioxide pump (200) is connected to the inlet of the gasifier (300) through a pipeline, and the outlet of the gasifier (300) is connected to the liquefied natural gas fine desulfurization component.

2. The carbon-neutral liquefied natural gas production device according to claim 1, characterized in that: The carbon-neutral liquefied natural gas production device further includes a low-pressure steam pipeline (400) and a condensate pipeline (500); The low-pressure steam pipeline (400) is connected to the inlet of the heating pipeline of the vaporizer (300), and the condensate pipeline (500) is connected to the inlet of the heating pipeline of the vaporizer (300). The low-pressure steam in the low-pressure steam pipeline (400) heats the vaporizer (300).

3. The carbon-neutral liquefied natural gas production device according to claim 1, characterized in that: There are a plurality of carbon dioxide storage tanks (100), and each of the plurality of carbon dioxide storage tanks (100) is connected to a main pipeline, and the main pipeline is connected to the air inlet.

4. The carbon-neutral liquefied natural gas production device according to claim 3, characterized in that: The carbon-neutral liquefied natural gas production device further comprises a plurality of control valves (600), and each of the carbon dioxide storage tanks (100) is provided with the control valve (600).

5. The carbon-neutral liquefied natural gas production device according to claim 4, characterized in that: The pipeline between the carbon dioxide storage tank (100) and the gasifier (300) is provided with the control valve (600).

6. The carbon-neutral liquefied natural gas production device according to claim 1, characterized in that: The carbon-neutral liquefied natural gas production device further comprises a flow regulating valve (700), and the flow regulating valve (700) is arranged on the pipeline between the gasifier (300) and the liquefied natural gas fine desulfurization component.

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