Raw gas liquefaction separation device

Abstract

The crude gas liquefaction and separation device comprises a first-stage heat exchanger, a second-stage heat exchanger and a third-stage heat exchanger, a secondary heat exchanger; a third-stage heat exchanger; the fourth-stage heat exchanger is used for further cooling the feed gas and is connected with the third-stage heat exchanger through a pipeline; the separator is connected with the four-stage heat exchanger through a pipeline, a gas phase outlet of the separator is connected with a hydrogen-rich gas discharge pipe, a liquid phase outlet of the separator is connected with a liquid phase discharge pipe, the liquid phase discharge pipe is connected with a rectifying tower, the tower bottom of the rectifying tower is connected with a liquefied natural gas discharge pipe, and the liquefied natural gas discharge pipe is connected with a liquefied natural gas outlet pipe. And the tower top of the rectifying tower is connected with a nitrogen-rich gas discharge pipe. According to the raw coke oven gas liquefaction separation device, methanation gas produced by an upstream methanation device is used as a raw material, a refrigeration process of'mixed refrigerant and nitrogen circulation 'is adopted, an LNG product and byproducts of hydrogen-rich gas and nitrogen-rich gas are efficiently obtained from the raw material gas, pollution is reduced, and cost is saved.

Description

Technical Field

[0001] The present invention relates to the liquefaction and recycling of gas, and in particular to a crude gas liquefaction and separation device. Background Art

[0002] In industrial production facilities, raw coal gas undergoes methanation, resulting in a mixture of hydrogen, nitrogen, methane, ethane, carbon monoxide, and other gases. Methane can be separated into LNG products, while nitrogen and hydrogen are excellent feedstocks for ammonia synthesis. Therefore, a device is needed to liquefy raw coal gas and efficiently separate the LNG products, nitrogen, and hydrogen. Utility Model Content

[0003] The purpose of the utility model is to provide a raw gas liquefaction separation device.

[0004] The utility model of the raw gas liquefaction separation device comprises:

[0005] A primary heat exchanger used to cool the raw gas and reduce its temperature;

[0006] A secondary heat exchanger for further cooling the raw gas is connected to the primary heat exchanger via a pipeline;

[0007] A third-stage heat exchanger for further cooling the raw gas is connected to the second-stage heat exchanger via a pipeline;

[0008] A fourth-stage heat exchanger for further cooling the raw gas is connected to the third-stage heat exchanger via a pipeline;

[0009] A separator for separating the raw gas into hydrogen-rich gas and liquid phase is connected to the four-stage heat exchanger through a pipeline. The gas phase outlet of the separator is connected to the hydrogen-rich gas discharge pipe, the liquid phase outlet of the separator is connected to the liquid phase discharge pipe, the liquid phase discharge pipe is connected to a distillation tower, the bottom of the distillation tower is connected to the liquefied natural gas discharge pipe, and the top of the distillation tower is connected to the nitrogen-rich gas discharge pipe.

[0010] In the utility model of the raw gas liquefaction separation device, the hydrogen-rich gas discharge pipe passes through the four-stage heat exchanger, the three-stage heat exchanger, the two-stage heat exchanger and the one-stage heat exchanger in sequence, so that the gas in the hydrogen-rich gas discharge pipe is reheated and then leaves the boundary area.

[0011] The utility model relates to a raw gas liquefaction and separation device, in which a first throttle valve is provided on the liquid phase discharge pipe, and the liquid phase discharge pipe passes through a four-stage heat exchanger and a three-stage heat exchanger in sequence, so that the liquid in the liquid phase discharge pipe is throttled and depressurized by the first throttle valve, and then enters the distillation tower after being reheated by the four-stage heat exchanger and the three-stage heat exchanger.

[0012] In the utility model of the raw gas liquefaction separation device, the nitrogen-rich gas discharge pipe passes through the four-stage heat exchanger, the three-stage heat exchanger, the two-stage heat exchanger and the one-stage heat exchanger in sequence, so that the gas in the nitrogen-rich gas discharge pipe is reheated and then leaves the boundary area.

[0013] The raw gas liquefaction and separation device of the present invention further includes a nitrogen refrigeration device, which includes:

[0014] Compressors for compressing nitrogen;

[0015] The second throttle valve is used for throttling and reducing the pressure of nitrogen. The air outlet of the compressor is connected to the second throttle valve through the first pipeline. The first pipeline passes through the first stage heat exchanger, the second stage heat exchanger, the third stage heat exchanger, and the fourth stage heat exchanger in sequence from the compressor. The outlet of the second throttle valve is connected to the air inlet of the compressor through the second pipeline, so that the nitrogen circulates between the compressor and the second throttle valve. The second pipeline passes through the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger, and the first stage heat exchanger in sequence, so that the gas in the second pipeline is the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger, and the second stage heat exchanger. , the first-stage heat exchanger provides cooling capacity, the nitrogen refrigeration device also includes a third pipeline, one end of the third pipeline is connected to the first pipeline, and the connection point is located between the fourth-stage heat exchanger and the second throttle valve, the other end of the third pipeline is connected to the second pipeline, and the connection point is located between the second throttle valve and the fourth-stage heat exchanger, and a third throttle valve is provided on the third pipeline. The third pipeline passes through the heat exchanger at the top of the distillation tower, so that the gas in the third pipeline provides cooling capacity for the heat exchanger at the top of the distillation tower after throttling and then returns to the fourth-stage heat exchanger.

[0016] The raw gas liquefaction and separation device of the present invention further includes a mixed refrigerant refrigeration device, which includes:

[0017] A mixed refrigerant compressor for compressing a mixed refrigerant, wherein the liquid-phase refrigerant outlet of the mixed refrigerant compressor is connected to a fourth throttle valve through a fourth pipeline, the outlet of the fourth throttle valve is connected to the inlet of the mixed refrigerant compressor through a return pipeline, the fourth pipeline passes through a primary heat exchanger, the return pipeline passes through a primary heat exchanger, the gas-phase refrigerant outlet of the mixed refrigerant compressor is connected to a fifth throttle valve through a fifth pipeline, the outlet of the fifth throttle valve is connected to a sixth pipeline, the other end of the sixth pipeline is connected to the return pipeline, the fifth pipeline passes through a primary heat exchanger, a secondary heat exchanger, a bottom reboiler, and a tertiary heat exchanger in sequence, and the sixth pipeline passes through a tertiary heat exchanger and a secondary heat exchanger in sequence.

[0018] Compared with the existing technology, the beneficial effects of the present invention are: the raw coal gas liquefaction and separation device of the present invention uses the methanized gas produced by the upstream methanation device as raw material, adopts the "mixed refrigerant + nitrogen circulation" refrigeration process, and efficiently obtains LNG products from the raw gas, and produces hydrogen-rich gas and nitrogen-rich gas as by-products, thereby reducing pollution and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the raw coal gas liquefaction separation device of the present utility model. DETAILED DESCRIPTION

[0020] like Figure 1 As shown, the crude gas liquefaction separation device of the present invention comprises:

[0021] The primary heat exchanger E1 is used to cool the raw gas and reduce its temperature;

[0022] The secondary heat exchanger E2, used to further cool the raw gas, is connected to the primary heat exchanger through a pipeline;

[0023] The third-stage heat exchanger E3, used to further cool the raw gas, is connected to the second-stage heat exchanger through a pipeline;

[0024] The fourth-stage heat exchanger E4, used to further cool the raw gas, is connected to the third-stage heat exchanger through a pipeline;

[0025] The separator V1 used to separate the raw gas into hydrogen-rich gas and liquid phase is connected to the four-stage heat exchanger through a pipeline. The gas phase outlet of the separator is connected to the hydrogen-rich gas discharge pipe 21, and the liquid phase outlet of the separator is connected to the liquid phase discharge pipe 22. The liquid phase discharge pipe is connected to the distillation tower T1. The bottom of the distillation tower is connected to the liquefied natural gas discharge pipe 23, and the top of the distillation tower is connected to the nitrogen-rich gas discharge pipe 24.

[0026] In the raw gas liquefaction and separation device of the present invention, the hydrogen-rich gas discharge pipe 21 passes through the fourth-stage heat exchanger, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger in sequence, so that the gas in the hydrogen-rich gas discharge pipe 21 is reheated and then flows out of the boundary area.

[0027] In the raw gas liquefaction and separation device of the present invention, a first throttle valve V11 is provided on the liquid phase discharge pipe 22, and the liquid phase discharge pipe passes through a four-stage heat exchanger and a three-stage heat exchanger in sequence, so that the liquid in the liquid phase discharge pipe is throttled and depressurized by the first throttle valve, and then enters the distillation tower T1 after being reheated by the four-stage heat exchanger and the three-stage heat exchanger.

[0028] In the crude gas liquefaction and separation device of the present invention, the nitrogen-rich gas discharge pipe 24 passes through the fourth-stage heat exchanger, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger in sequence, so that the gas in the nitrogen-rich gas discharge pipe is reheated and then flows out of the boundary area.

[0029] The raw gas liquefaction and separation device of the present invention further includes a nitrogen refrigeration device, which includes:

[0030] Compressors for compressing nitrogen;

[0031] The second throttle valve V12 is used for throttling and reducing the pressure of nitrogen. The air outlet of the compressor is connected to the second throttle valve through the first pipeline 1. The first pipeline 1 passes through the first stage heat exchanger, the second stage heat exchanger, the third stage heat exchanger and the fourth stage heat exchanger in sequence from the compressor. The outlet of the second throttle valve V12 is connected to the air inlet of the compressor through the second pipeline 2, so that the nitrogen circulates between the compressor and the second throttle valve. The second pipeline 2 passes through the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger and the first stage heat exchanger in sequence, so that the gas in the second pipeline is the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger and the second stage heat exchanger. The nitrogen refrigeration device further comprises a third pipeline 3, one end of which is connected to the first pipeline at a point between the fourth-stage heat exchanger and the second throttle valve, and the other end of which is connected to the second pipeline at a point between the second throttle valve and the fourth-stage heat exchanger. A third throttle valve V13 is provided on the third pipeline. The third pipeline 3 passes through the heat exchanger E6 at the top of the distillation tower, so that the gas in the third pipeline, after throttling, provides cooling to the heat exchanger at the top of the distillation tower and then returns to the fourth-stage heat exchanger.

[0032] The raw gas liquefaction and separation device of the present invention further includes a mixed refrigerant refrigeration device, which includes:

[0033] A mixed refrigerant compressor for compressing a mixed refrigerant, the liquid-phase refrigerant outlet of the mixed refrigerant compressor is connected to the fourth throttle valve V14 through the fourth pipeline 4, the outlet of the fourth throttle valve is connected to the inlet of the mixed refrigerant compressor through the return pipeline 9, the fourth pipeline 4 passes through the first-stage heat exchanger, the return pipeline 9 passes through the first-stage heat exchanger, the gas-phase refrigerant outlet of the mixed refrigerant compressor is connected to the fifth throttle valve V15 through the fifth pipeline 5, the outlet of the fifth throttle valve is connected to the sixth pipeline 6, the other end of the sixth pipeline is connected to the return pipeline, the fifth pipeline 5 passes through the first-stage heat exchanger, the second-stage heat exchanger, the bottom reboiler E5, and the third-stage heat exchanger in sequence, and the sixth pipeline 6 passes through the third-stage heat exchanger and the second-stage heat exchanger in sequence.

[0034] Compared with the existing technology, the beneficial effects of the present invention are: the raw coal gas liquefaction and separation device of the present invention uses the methanized gas produced by the upstream methanation device as raw material, adopts the "mixed refrigerant + nitrogen circulation" refrigeration process, and efficiently obtains LNG products from the raw gas, and produces hydrogen-rich gas and nitrogen-rich gas as by-products, thereby reducing pollution and saving costs.

[0035] The utility model relates to a raw gas liquefaction and separation device which adopts a mixed refrigerant + nitrogen circulation refrigeration process, and its main equipment includes a heat exchanger, a distillation tower, a separator and related valves and pipelines.

[0036] In the raw gas liquefaction separation device of the present invention, the heat exchanger can be a plate-fin heat exchanger, a plate heat exchanger, a coiled-tube heat exchanger, a shell-and-tube heat exchanger, or a combination thereof.

[0037] The raw gas is a mixture of hydrogen, nitrogen, methane, ethane, carbon monoxide and other gases.

[0038] The distillation column can be a packed column, a plate column or a bubble cap column.

[0039] The refrigerant is any combination of methane, ethylene, propane, nitrogen, isopentane, etc.

[0040] The working process of the crude gas liquefaction separation device of the utility model is as follows:

[0041] The raw gas enters the primary heat exchanger E1, the secondary heat exchanger E2, the tertiary heat exchanger E3, and the quaternary heat exchanger E4 in sequence for cooling, and then enters the separator V1. The hydrogen-rich gas is discharged from the top of the separator, and passes through the quaternary heat exchanger E4, the tertiary heat exchanger E3, the secondary heat exchanger E2, and the primary heat exchanger E1 for reheating before exiting the boundary area. The liquid is discharged from the bottom of the tower, throttled and reduced in pressure by the first throttle valve V11, and then reheated by the quaternary heat exchanger E4 and the tertiary heat exchanger E3 before entering the distillation tower T1. After undergoing heat and mass transfer processes in the tower, the methane enriched at the bottom of the tower is further cooled by the tertiary heat exchanger E3 and output as LNG products. The nitrogen-rich gas at the top of the tower passes through the quaternary heat exchanger E4, the tertiary heat exchanger E3, the secondary heat exchanger E2, and the primary heat exchanger E1 for reheating before exiting the boundary area.

[0042] The nitrogen from the compressor enters the first-stage heat exchanger E1, the second-stage heat exchanger E2, the third-stage heat exchanger E3, and the fourth-stage heat exchanger E4 in sequence, where it is cooled and then split into two streams. One stream is throttled and enters the heat exchanger E6 at the top of the distillation tower T1, providing cooling capacity and then returns to the inlet of the fourth-stage heat exchanger E4. The other stream is throttled and merges with the returning nitrogen, and finally passes through the fourth-stage heat exchanger E4, the third-stage heat exchanger E3, the second-stage heat exchanger E2, and the first-stage heat exchanger E1 in sequence to be reheated and then returns to the compressor inlet.

[0043] The liquid-phase refrigerant from the mixed refrigerant compressor enters the primary heat exchanger E1 for cooling, and then passes through the throttle valve for cooling and pressure reduction. The gas-phase refrigerant from the mixed refrigerant compressor enters the primary heat exchanger E1, the secondary heat exchanger E2, the bottom reboiler E5, and the tertiary heat exchanger E3 for cooling, and then passes through the throttle valve for cooling and pressure reduction. It then enters the tertiary heat exchanger E3 and the secondary heat exchanger E2 in sequence, merges with the liquid-phase refrigerant, exchanges heat through the primary heat exchanger E1, and finally returns to the compressor inlet.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A crude gas liquefaction separation device, characterized in that: include: A primary heat exchanger used to cool the raw gas and reduce its temperature; A secondary heat exchanger for further cooling the raw gas is connected to the primary heat exchanger via a pipeline; A third-stage heat exchanger for further cooling the raw gas is connected to the second-stage heat exchanger via a pipeline; A fourth-stage heat exchanger for further cooling the raw gas is connected to the third-stage heat exchanger via a pipeline; A separator for separating the raw gas into hydrogen-rich gas and liquid phase is connected to the four-stage heat exchanger through a pipeline. The gas phase outlet of the separator is connected to the hydrogen-rich gas discharge pipe, the liquid phase outlet of the separator is connected to the liquid phase discharge pipe, the liquid phase discharge pipe is connected to a distillation tower, the bottom of the distillation tower is connected to the liquefied natural gas discharge pipe, and the top of the distillation tower is connected to the nitrogen-rich gas discharge pipe.

2. The crude gas liquefaction separation device according to claim 1, characterized in that: The hydrogen-rich gas discharge pipe passes through the fourth-stage heat exchanger, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger in sequence, so that the gas in the hydrogen-rich gas discharge pipe is reheated and then leaves the boundary area.

3. The crude gas liquefaction separation device according to claim 2, characterized in that: A first throttle valve is provided on the liquid phase discharge pipe, and the liquid phase discharge pipe passes through the fourth-stage heat exchanger and the third-stage heat exchanger in sequence, so that the liquid in the liquid phase discharge pipe is throttled and depressurized by the first throttle valve, and then enters the distillation tower after being reheated by the fourth-stage heat exchanger and the third-stage heat exchanger.

4. The crude gas liquefaction separation device according to claim 3, characterized in that: The nitrogen-rich gas discharge pipe passes through the fourth-stage heat exchanger, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger in sequence, so that the gas in the nitrogen-rich gas discharge pipe is reheated and then leaves the boundary area.

5. The crude gas liquefaction separation device according to claim 4, characterized in that: Also included is a nitrogen refrigeration device, the nitrogen refrigeration device comprising: Compressors for compressing nitrogen; The second throttle valve is used for throttling and reducing the pressure of nitrogen. The air outlet of the compressor is connected to the second throttle valve through the first pipeline. The first pipeline passes through the first stage heat exchanger, the second stage heat exchanger, the third stage heat exchanger, and the fourth stage heat exchanger in sequence from the compressor. The outlet of the second throttle valve is connected to the air inlet of the compressor through the second pipeline, so that the nitrogen circulates between the compressor and the second throttle valve. The second pipeline passes through the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger, and the first stage heat exchanger in sequence, so that the gas in the second pipeline is the fourth stage heat exchanger, the third stage heat exchanger, the second stage heat exchanger, and the second stage heat exchanger. , the first-stage heat exchanger provides cooling capacity, the nitrogen refrigeration device also includes a third pipeline, one end of the third pipeline is connected to the first pipeline, and the connection point is located between the fourth-stage heat exchanger and the second throttle valve, the other end of the third pipeline is connected to the second pipeline, and the connection point is located between the second throttle valve and the fourth-stage heat exchanger, and a third throttle valve is provided on the third pipeline. The third pipeline passes through the heat exchanger at the top of the distillation tower, so that the gas in the third pipeline provides cooling capacity for the heat exchanger at the top of the distillation tower after throttling and then returns to the fourth-stage heat exchanger.

6. The crude gas liquefaction separation device according to claim 5, characterized in that: Also included is a mixed refrigerant refrigeration device, the mixed refrigerant refrigeration device comprising: A mixed refrigerant compressor for compressing a mixed refrigerant, wherein the liquid-phase refrigerant outlet of the mixed refrigerant compressor is connected to a fourth throttle valve through a fourth pipeline, the outlet of the fourth throttle valve is connected to the inlet of the mixed refrigerant compressor through a return pipeline, the fourth pipeline passes through a primary heat exchanger, the return pipeline passes through a primary heat exchanger, the gas-phase refrigerant outlet of the mixed refrigerant compressor is connected to a fifth throttle valve through a fifth pipeline, the outlet of the fifth throttle valve is connected to a sixth pipeline, the other end of the sixth pipeline is connected to the return pipeline, the fifth pipeline passes through a primary heat exchanger, a secondary heat exchanger, a bottom reboiler, and a tertiary heat exchanger in sequence, and the sixth pipeline passes through a tertiary heat exchanger and a secondary heat exchanger in sequence.

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