Device for preparing liquefied natural gas (LNG), hydrogen and nitrogen from semi-coke tail gas
The semi-coke tail gas is separated into LNG and hydrogen nitrogen through a multi-stage cooling and separation device, which solves the problem of semi-coke tail gas separation, improves economic and environmental benefits, simplifies the process and reduces costs.
Patent Information
- Application Number
- CN202520287988.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-22
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-02-22
AI Technical Summary
Existing technologies are insufficient to efficiently, energy-savingly, and environmentally friendly separate and purify different components of semi-coke tail gas, and the utilization rate of semi-coke tail gas is low, resulting in insufficient economic and environmental benefits.
The device, which includes one to four stages of heat exchangers and distillation columns, separates the component gases in the semi-coke tail gas into LNG and hydrogen and nitrogen through a multi-stage cooling and separation process. The cooling capacity is provided by a mixed refrigerant and a nitrogen refrigeration unit, simplifying the process into a two-column distillation process.
It achieves efficient separation of semi-coke tail gas, obtains high-purity products, improves economic value, simplifies the process, reduces costs, and lowers the difficulty of operation.
Smart Images
Figure CN223939763U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to cryogenic separation of component gases, and in particular to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas. Background Technology
[0002] Semi-coke, also known as semi-coke, is a solid substance with a high fixed carbon content produced by medium-low temperature dry distillation. Coal tar and semi-coke tail gas are produced as byproducts during the production of semi-coke.
[0003] The main components of semi-coke tail gas are H2, CH4, CO and N2. Due to its high nitrogen content and many impurities, it has always been difficult to process and utilize, and most semi-coke tail gas is only used for combustion power generation.
[0004] How to efficiently, energy-savingly, and environmentally friendly separate and purify different components of semi-coke tail gas, and improve the quality of the produced products, so as to achieve a win-win situation of economic and environmental benefits, is an urgent problem to be solved. Utility Model Content
[0005] The purpose of this invention is to provide an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas.
[0006] The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas of this utility model includes:
[0007] A primary heat exchanger used to cool the raw gas and lower its temperature;
[0008] The secondary heat exchanger, used for further cooling of the raw gas, is connected to the primary heat exchanger via pipeline;
[0009] A tertiary heat exchanger for further cooling of the raw gas is connected to the secondary heat exchanger via pipeline.
[0010] The fourth-stage heat exchanger is used to further cool the raw gas and is connected to the third-stage heat exchanger via pipeline.
[0011] A primary distillation column is connected to a fourth-stage heat exchanger via pipelines. The bottom of the primary distillation column is connected to one end of a drain pipe for discharging liquid methane and ethane. The top of the primary distillation column is connected to a first top condenser via pipelines. The first top condenser is connected to a first top separator via pipelines. The liquid phase discharge pipe of the first top separator is connected to the primary distillation column. The gas phase discharge port of the first top separator is connected to a hydrogen discharge pipe.
[0012] The other end of the drain pipe is connected to the secondary distillation column. The bottom of the secondary distillation column is connected to the reboiler through a pipeline. The gas phase outlet of the reboiler is connected to the methane discharge pipe. The methane discharge pipe passes through a tertiary heat exchanger to cool the gas in the methane discharge pipe and obtain LNG.
[0013] The top of the secondary distillation column is connected to a second top condenser via a pipeline. The second top condenser is connected to a second top separator via a pipeline. The liquid phase discharge pipe of the second top separator is connected to the secondary distillation column, and the gas phase discharge port of the second top separator is connected to a nitrogen discharge pipe.
[0014] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the hydrogen exhaust pipe passes sequentially through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger, so that the gas in the hydrogen exhaust pipe is reheated before leaving the boundary area.
[0015] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the nitrogen discharge pipe passes sequentially through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger, so that the gas in the nitrogen discharge pipe is reheated before leaving the boundary area.
[0016] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the drain pipe passes through a four-stage heat exchanger and a three-stage heat exchanger in sequence, so that the liquid in the drain pipe is reheated before entering the two-stage distillation column.
[0017] This utility model discloses an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, which further includes a nitrogen refrigeration device. The nitrogen refrigeration device includes: a nitrogen inlet pipe; the nitrogen inlet pipe sequentially passes through a primary heat exchanger, a secondary heat exchanger, a tertiary heat exchanger, and a quaternary heat exchanger, and then connects to a nitrogen outlet pipe via a first branch pipe and a second branch pipe, respectively. The first branch pipe sequentially passes through a first throttling valve and a first top condenser; the second branch pipe sequentially passes through a second throttling valve and a second top condenser; the nitrogen outlet pipe sequentially passes through a quaternary heat exchanger, a tertiary heat exchanger, a secondary heat exchanger, and a primary heat exchanger, so that the throttled nitrogen provides cooling capacity to the first top condenser, the second top condenser, the quaternary heat exchanger, the tertiary heat exchanger, the secondary heat exchanger, and the primary heat exchanger.
[0018] This utility model discloses an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, which further includes a mixed refrigerant refrigeration device. The mixed refrigerant refrigeration device includes a mixed refrigerant liquid phase inlet pipe, a mixed refrigerant outlet pipe, and a mixed refrigerant gas phase inlet pipe. The mixed refrigerant liquid phase inlet pipe is connected to a third throttle valve, and the outlet of the third throttle valve is connected to the mixed refrigerant outlet pipe. The mixed refrigerant liquid phase inlet pipe passes through a primary heat exchanger, and the mixed refrigerant outlet pipe passes through a primary heat exchanger. The mixed refrigerant gas phase inlet pipe passes through a primary heat exchanger, a secondary heat exchanger, a reboiler, and a tertiary heat exchanger in sequence. The connecting pipe passes through a tertiary heat exchanger and a secondary heat exchanger in sequence.
[0019] The advantages of this utility model's device for producing LNG and hydrogen / nitrogen from semi-coke tail gas are: it can efficiently separate the various components of semi-coke tail gas to obtain corresponding high-purity products, thereby improving the economic value of semi-coke tail gas; it reduces the original three-tower distillation to two-tower distillation, simplifying the process and greatly saving construction costs; the reboiler and condenser are controlled independently, facilitating efficient product production and also greatly reducing the difficulty of operation. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the device for producing LNG and hydrogen / nitrogen from semi-coke tail gas according to this utility model. Detailed Implementation
[0021] like Figure 1 As shown, the apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas according to this utility model includes:
[0022] E1 is a primary heat exchanger used to cool the raw gas and lower its temperature.
[0023] The secondary heat exchanger E2, used for further cooling of the raw gas, is connected to the primary heat exchanger via a pipeline.
[0024] The third-stage heat exchanger E3, used for further cooling of the raw gas, is connected to the second-stage heat exchanger via pipeline.
[0025] The fourth-stage heat exchanger E4, used for further cooling of the raw gas, is connected to the third-stage heat exchanger via pipeline.
[0026] A primary distillation column T1 is connected to a fourth-stage heat exchanger via a pipeline. The bottom of the primary distillation column is connected to one end of a drain pipe G1 for discharging liquid methane and ethane. The top of the primary distillation column is connected to a first top condenser E6 via a pipeline. The first top condenser is connected to a first top separator V1 via a pipeline. The liquid phase discharge pipe of the first top separator is connected to the primary distillation column. The gas phase discharge port of the first top separator is connected to a hydrogen discharge pipe 7.
[0027] The other end of the drain pipe is connected to the secondary distillation column T2. The bottom of the secondary distillation column is connected to the reboiler E5 through a pipeline. The gas phase outlet of the reboiler is connected to the methane discharge pipe 9. The methane discharge pipe 9 passes through a tertiary heat exchanger to cool the gas in the methane discharge pipe and obtain LNG.
[0028] The top of the secondary distillation column is connected to the second top condenser E7 via a pipeline. The second top condenser is connected to the second top separator V2 via a pipeline. The liquid phase discharge pipe of the second top separator is connected to the secondary distillation column, and the gas phase discharge port of the second top separator is connected to the nitrogen discharge pipe 8.
[0029] The raw material gas is the purified semi-coke tail gas.
[0030] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the hydrogen discharge pipe 7 passes sequentially through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger, so that the gas in the hydrogen discharge pipe is reheated before leaving the boundary area.
[0031] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the nitrogen discharge pipe 8 passes sequentially through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger, so that the gas in the nitrogen discharge pipe is reheated before leaving the boundary area.
[0032] The present invention relates to an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, wherein the drain pipe G1 passes through a four-stage heat exchanger and a three-stage heat exchanger in sequence, so that the liquid in the drain pipe is reheated before entering the two-stage distillation column.
[0033] The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas of this utility model further includes a nitrogen refrigeration device, which comprises:
[0034] Nitrogen inlet pipe 4;
[0035] The nitrogen inlet pipe passes sequentially through the primary heat exchanger, the secondary heat exchanger, the tertiary heat exchanger, and the quaternary heat exchanger, and then connects to the nitrogen outlet pipe 6 through the first branch pipe 11 and the second branch pipe 12, respectively.
[0036] The first branch pipe passes sequentially through the first throttling valve 21 and the first tower top condenser;
[0037] The second branch pipe passes sequentially through the second throttle valve 22 and the second tower top condenser;
[0038] The nitrogen outlet pipe 6 passes through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger in sequence, so that the throttled nitrogen provides cooling capacity to the first and second overhead condensers, the fourth and third-stage heat exchangers, the second and first-stage heat exchangers.
[0039] This utility model discloses an apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, which further includes a mixed refrigerant refrigeration device. The mixed refrigerant refrigeration device includes a mixed refrigerant liquid phase inlet pipe 1, a mixed refrigerant outlet pipe 5, and a mixed refrigerant gas phase inlet pipe 2. The mixed refrigerant liquid phase inlet pipe 1 is connected to a third throttle valve 23, and the outlet of the third throttle valve is connected to the mixed refrigerant outlet pipe 5. The mixed refrigerant liquid phase inlet pipe 1 passes through a primary heat exchanger, and the mixed refrigerant outlet pipe 5 passes through a primary heat exchanger. The mixed refrigerant gas phase inlet pipe 2 is connected to a fourth throttle valve 24, and the outlet of the fourth throttle valve 24 is connected to a connecting pipe 33. The other end of the connecting pipe 33 is connected to the mixed refrigerant outlet pipe 5. The mixed refrigerant gas phase inlet pipe 2 passes sequentially through a primary heat exchanger, a secondary heat exchanger, a reboiler E5, and a tertiary heat exchanger. The connecting pipe 33 passes sequentially through a tertiary heat exchanger and a secondary heat exchanger.
[0040] The working process of the device for producing LNG and hydrogen / nitrogen from semi-coke tail gas according to this invention is as follows:
[0041] The purified semi-coke tail gas 3 flows through 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 before flowing through the first-stage distillation column T1. Liquid products with relatively high boiling points, such as methane and ethane, are discharged from the bottom. After being cooled by the first-stage overhead condenser E6, the liquid phase enters the first-stage overhead separator V1. The liquid phase is refluxed back to the first-stage distillation column T1. After being further cooled by the third-stage heat exchanger E3 and the fourth-stage heat exchanger E4, the liquid phase is sent to the second-stage distillation column T2. The gas phase flows 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 to obtain products mainly composed of hydrogen.
[0042] At the bottom of the secondary distillation column T2, fuel gas, mainly composed of methane, is separated by a reboiler. This fuel gas is cooled by the main tertiary heat exchanger E3 to obtain the product LNG. After being cooled by the second overhead condenser E7, the LNG enters the second overhead separator V2. The liquid phase flows back to the secondary distillation column T2, while the gas phase flows through the fourth heat exchanger E4, the third heat exchanger E3, the second heat exchanger E2, and the first heat exchanger E1 to obtain the product, mainly composed of nitrogen.
[0043] The cooling energy for the first overhead condenser E6 and the second overhead condenser E7 comes from nitrogen. The heat for the reboiler at the bottom of the second-stage distillation column T2 comes from the mixed refrigerant gas phase.
[0044] The cooling capacity of the entire device comes from the circulating cooling of a mixture of gaseous and liquid refrigerants and the circulating cooling of nitrogen.
[0045] The advantages of this utility model's device for producing LNG and hydrogen / nitrogen from semi-coke tail gas are: it can efficiently separate the various components of semi-coke tail gas to obtain corresponding high-purity products, thereby improving the economic value of semi-coke tail gas; it reduces the original three-tower distillation to two-tower distillation, simplifying the process and greatly saving construction costs; the reboiler and condenser are controlled independently, facilitating efficient product production and also greatly reducing the difficulty of operation.
[0046] The reboiler E5, the second top condenser E7, and the first top condenser E6 in the device for producing LNG and hydrogen / nitrogen from semi-coke tail gas of this invention each have an independently equipped system that can control the operating temperature of the relevant equipment through an independent system, so as to efficiently and stably produce the required products.
[0047] The device for producing LNG and hydrogen / nitrogen from semi-coke tail gas of this invention is not limited to processing semi-coke tail gas, but can also process petroleum tail gas, natural gas, etc.
[0048] Distillation columns can be packed columns, plate columns, or sieve plate columns.
[0049] The heat exchanger can be a plate-fin heat exchanger or a coiled tube heat exchanger.
[0050] Liquefied natural gas (LNG), whose main component is methane, is widely recognized as the cleanest fossil fuel on Earth.
[0051] LNG can be a mixture of methane, ethylene, ethane, etc.
[0052] In the preparation of hydrogen and nitrogen, the production ratio of hydrogen and nitrogen can be achieved by controlling the temperature of the primary distillation column T1 and the secondary distillation column T2.
[0053] In this invention, the apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas operates as follows: The purified semi-coke tail gas, after heat exchange, flows through a primary distillation column. Liquid products with high boiling points, such as methane and ethane, are discharged from the bottom. The top of the column is cooled by the overhead condenser and then enters the overhead separator. The gas phase, after heat exchange, yields a product primarily composed of hydrogen. The liquid phase is refluxed back to the primary distillation column, further cooled by heat exchange, and then sent to a secondary distillation column. After passing through the reboiler, a fuel gas primarily composed of methane is discharged. This fuel gas is a mixture of hydrogen, methane, ethane, etc. After cooling, this fuel gas yields LNG. The top discharge is cooled by the overhead condenser of the secondary distillation column and then enters the overhead separator. The liquid phase is refluxed back to the secondary distillation column, and the gas phase, after heat exchange, yields a product primarily composed of nitrogen.
[0054] The heat source for the reboiler of the secondary distillation column can be a refrigerant or a feed gas, and can be configured according to different requirements, all of which are within the protection scope of this utility model.
[0055] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. An apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas, characterized in that, include: A primary heat exchanger used to cool the raw gas and lower its temperature; The secondary heat exchanger, used for further cooling of the raw gas, is connected to the primary heat exchanger via pipeline; A tertiary heat exchanger for further cooling of the raw gas is connected to the secondary heat exchanger via pipeline. The fourth-stage heat exchanger is used to further cool the raw gas and is connected to the third-stage heat exchanger via pipeline. A primary distillation column is connected to a fourth-stage heat exchanger via pipelines. The bottom of the primary distillation column is connected to one end of a drain pipe for discharging liquid methane and ethane. The top of the primary distillation column is connected to a first top condenser via pipelines. The first top condenser is connected to a first top separator via pipelines. The liquid phase discharge pipe of the first top separator is connected to the primary distillation column. The gas phase discharge port of the first top separator is connected to a hydrogen discharge pipe. The other end of the drain pipe is connected to the secondary distillation column. The bottom of the secondary distillation column is connected to the reboiler through a pipeline. The gas phase outlet of the reboiler is connected to the methane discharge pipe. The methane discharge pipe passes through a tertiary heat exchanger to cool the gas in the methane discharge pipe and obtain LNG. The top of the secondary distillation column is connected to a second top condenser via a pipeline. The second top condenser is connected to a second top separator via a pipeline. The liquid phase discharge pipe of the second top separator is connected to the secondary distillation column, and the gas phase discharge port of the second top separator is connected to a nitrogen discharge pipe.
2. The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas as described in claim 1, characterized in that, The hydrogen exhaust pipe passes through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger in sequence, so that the gas in the hydrogen exhaust pipe can be reheated before leaving the boundary area.
3. The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas as described in claim 2, characterized in that, The nitrogen exhaust pipe passes through a four-stage heat exchanger, a three-stage heat exchanger, a two-stage heat exchanger, and a one-stage heat exchanger in sequence, so that the gas in the nitrogen exhaust pipe can be reheated before leaving the boundary area.
4. The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas as described in claim 3, characterized in that, The drain pipe passes through a four-stage heat exchanger and a three-stage heat exchanger in sequence, so that the liquid in the drain pipe is reheated before entering the two-stage distillation column.
5. The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas as described in claim 4, characterized in that, It also includes a nitrogen refrigeration device, which comprises: a nitrogen inlet pipe; the nitrogen inlet pipe passes sequentially through a primary heat exchanger, a secondary heat exchanger, a tertiary heat exchanger, and a quaternary heat exchanger, and then connects to a nitrogen outlet pipe through a first branch pipe and a second branch pipe, respectively; the first branch pipe passes sequentially through a first throttling valve and a first top condenser; the second branch pipe passes sequentially through a second throttling valve and a second top condenser; the nitrogen outlet pipe passes sequentially through a quaternary heat exchanger, a tertiary heat exchanger, a secondary heat exchanger, and a primary heat exchanger, so that the throttled nitrogen provides cooling capacity to the first top condenser, the second top condenser, the quaternary heat exchanger, the tertiary heat exchanger, the secondary heat exchanger, and the primary heat exchanger.
6. The apparatus for producing LNG and hydrogen / nitrogen from semi-coke tail gas as described in claim 5, characterized in that, It also includes a mixed refrigerant refrigeration device, which includes a mixed refrigerant liquid phase inlet pipe, a mixed refrigerant outlet pipe, and a mixed refrigerant gas phase inlet pipe. The mixed refrigerant liquid phase inlet pipe is connected to a third throttle valve, and the outlet of the third throttle valve is connected to the mixed refrigerant outlet pipe. The mixed refrigerant liquid phase inlet pipe passes through a primary heat exchanger, and the mixed refrigerant outlet pipe passes through a primary heat exchanger. The mixed refrigerant gas phase inlet pipe is connected to a fourth throttle valve, and the outlet of the fourth throttle valve is connected to a connecting pipeline. The other end of the connecting pipeline is connected to the mixed refrigerant outlet pipe. The mixed refrigerant gas phase inlet pipe passes sequentially through a primary heat exchanger, a secondary heat exchanger, a reboiler, and a tertiary heat exchanger. The connecting pipeline passes sequentially through a tertiary heat exchanger and a secondary heat exchanger.