System for recycling hydrogen and increasing yield of light dydrocarbon by membrane method

Abstract

The utility model discloses a system for increasing yield of light hydrocarbon by recovering hydrogen through a membrane method. The system comprises a heater, a membrane separator, a water cooler, a gas-gas heat exchanger, a condenser and a gas-liquid separator which are connected in sequence, a raw material gas pipeline is arranged at one end of the heater; a hydrogen product pipeline is arranged on the membrane separator; a light hydrocarbon product pipeline is arranged at one end of the gas-liquid separator. According to the application, the high-temperature-resistant membrane separator is used for recovering hydrogen on the permeation side, and meanwhile, a hydrocarbon dew point as high as possible is obtained on the non-permeation side, and when the hydrocarbon dew point is higher, the condensation recovery rate of downstream light hydrocarbon is higher; meanwhile, the high-efficiency recycling rate of hydrogen and light hydrocarbon is realized. In addition, the gas-gas heat exchanger arranged in the system can recycle cold energy, the load of the condenser and the use amount of the refrigerant are reduced, and therefore energy consumption is further reduced.

Description

Technical Field

[0001] This application relates to a membrane-based system for hydrogen recovery and light hydrocarbon production, belonging to the field of membrane separation technology. Background Technology

[0002] With the acceleration of global industrialization, the demand for hydrogen, as a clean energy source, is constantly increasing. Hydrogen is not only used in fuel cells and chemical synthesis, but also plays a crucial role in promoting energy transition and reducing carbon emissions. Meanwhile, light hydrocarbons, as important chemical raw materials, are widely used in the production of plastics, rubber, and synthetic fibers. In the production processes of petrochemical and refining industries, many processes such as catalytic reforming, hydrocracking, hydrorefining, and secondary processing such as catalytic cracking generate large amounts of tail gas rich in hydrogen and light hydrocarbons. If these resources are not effectively recycled and utilized, it will not only lead to resource waste but also have adverse environmental impacts.

[0003] Membrane separation technology, as an emerging separation technology, has been widely used in the field of gas separation in recent years. This technology has advantages such as low energy consumption, simple process, convenient operation, and low equipment investment. Its principle is to utilize the pressure difference of the gas on both sides of the membrane as the driving force, and based on the difference in the permeation rate of different gases in the mixed gas within the membrane, to achieve efficient separation of hydrogen from other gases, i.e., recovering hydrogen on the permeate side and recovering light hydrocarbons on the tail gas side. Therefore, this application provides a novel membrane-based hydrogen recovery and light hydrocarbon production enhancement system that increases the yield of light hydrocarbons while recovering hydrogen. Utility Model Content

[0004] This invention proposes a membrane-based hydrogen recovery and light hydrocarbon production enhancement system, which is precisely adapted to the entire process of petrochemical and refining production. It constructs an efficient recovery system for the hydrogen and light hydrocarbon resources abundant in process tail gas.

[0005] According to one aspect of this application, a membrane-based hydrogen recovery system for increasing the production of light hydrocarbons is provided, the system comprising a heater, a membrane separator, a water cooler, a gas-to-gas heat exchanger, a condenser, and a gas-liquid separator connected in sequence.

[0006] One end of the heater is equipped with a raw material gas pipeline;

[0007] The membrane separator is equipped with a hydrogen product pipeline;

[0008] One end of the gas-liquid separator is equipped with a light hydrocarbon product pipeline.

[0009] Optionally, the membrane separator is used to separate hydrogen from hydrocarbons in the feed gas.

[0010] Optionally, the system further includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline, and an exhaust gas pipeline;

[0011] The heater is connected to the membrane separator via a first pipeline, the membrane separator is connected to the water cooler via a second pipeline, the water cooler is connected to the gas-to-gas heat exchanger via a third pipeline, the gas-to-gas heat exchanger is connected to the condenser via a fourth pipeline, and the condenser is connected to the gas-liquid separator via a fifth pipeline.

[0012] The gas-to-gas heat exchanger is equipped with an exhaust gas pipeline.

[0013] Optionally, the system further includes a first permeation-side outlet, a first interception-side outlet, a first hot flow outlet, a first cold flow outlet, a first liquid phase outlet, and a first gas phase outlet;

[0014] The first permeate-side outlet is located at the connection between the membrane separator and the hydrogen product pipeline;

[0015] The first interception side outlet is located at the connection between the membrane separator and the second pipeline;

[0016] The first hot flow outlet is located at the connection between the gas-to-gas heat exchanger and the fifth pipeline;

[0017] The first cold flow outlet is located at the connection between the gas-to-gas heat exchanger and the exhaust gas pipeline.

[0018] The first liquid phase outlet is located at the connection between the gas-liquid separator and the light hydrocarbon product pipeline.

[0019] The first gas phase outlet is located at the connection between the gas-liquid separator and the sixth pipeline.

[0020] Optionally, the dew point temperature of the stream at the first retrieval outlet of the membrane separator is not lower than 80°C. The dew point temperature of the stream on the first retrieval side of the membrane separator is not lower than 80°C to achieve a higher light hydrocarbon recovery rate.

[0021] Optionally, the membrane separator has a temperature resistance of not less than 90°C. This temperature resistance ensures that the membrane separation process takes place in a gaseous environment.

[0022] The beneficial effects that this application can produce include:

[0023] This application utilizes a high-temperature resistant membrane separator to recover hydrogen on the permeate side while simultaneously achieving the highest possible hydrocarbon dew point on the non-permeate side. A higher hydrocarbon dew point results in a higher condensation recovery rate of downstream light hydrocarbons, thus achieving efficient recovery and utilization of both hydrogen and light hydrocarbons. Furthermore, the gas-to-gas heat exchanger in this system can recover cooling capacity, reduce the load on the condenser and the amount of refrigerant used, thereby further reducing energy consumption. Attached Figure Description

[0024] Figure 1This is a schematic diagram of a membrane-based hydrogen recovery and light hydrocarbon production system disclosed in an embodiment of this utility model.

[0025] In the diagram: 1. Heater; 2. Membrane separator; 201. First permeate side outlet; 202. First retrieval side outlet; 3. Water cooler; 4. Gas-gas heat exchanger; 401. First hot stream outlet; 402. First cold stream outlet; 5. Condenser; 6. Gas-liquid separator; 601. First liquid phase outlet; 602. First gas phase outlet; a. Feed gas pipeline; b. First pipeline; c. Hydrogen product pipeline; d. Second pipeline; e. Third pipeline; f. Fourth pipeline; g. Fifth pipeline; h. Light hydrocarbon product pipeline; i. Sixth pipeline; j. Emission gas pipeline. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Example 1

[0027] like Figure 1 The image shows a membrane-based hydrogen recovery and light hydrocarbon production enhancement system provided in this embodiment, including a heater 1, a membrane separator 2, a water cooler 3, a gas-to-gas heat exchanger 4, a condenser 5, and a gas-liquid separator 6. The membrane separator is used to separate hydrogen from hydrocarbons in the feed gas. The dew point temperature of the first retentate side of the membrane separator is not lower than 80°C to obtain a higher light hydrocarbon recovery rate. The membrane separator has a temperature resistance of not lower than 90°C to ensure that the membrane separation process is carried out in a gas phase environment.

[0028] The feed gas is connected to the heater 1 via feed gas pipeline a. After being heated to a suitable temperature, it is connected to the membrane separator 2 via the first pipeline b. The enriched hydrogen is connected to the hydrogen product pipeline c via the first permeate outlet 201 of the membrane separator 2. The non-permeate gas is connected to the gas-gas heat exchanger 4 via the second pipeline d, water cooler 3, and third pipeline e via the first interception outlet 202 of the membrane separator 1. After heat exchange, the non-permeate gas is connected to the gas-liquid separator 6 via the fourth pipeline f, condenser 5, and fifth pipeline g via the first hot stream outlet 401 of the gas-gas heat exchanger 4. The enriched light hydrocarbons are connected to the light hydrocarbon product pipeline h via the first liquid phase outlet 601 of the gas-liquid separator 6. The non-condensable vapors are connected to the gas-gas heat exchanger 4 via the sixth pipeline i via the first gas phase outlet 602 of the gas-liquid separator 6. After cold recovery, the non-condensable vapors are connected to the exhaust gas pipeline j via the first cold stream outlet 402 of the gas-gas heat exchanger 4.

[0029] Example 2

[0030] The specific process of the membrane-based hydrogen recovery and light hydrocarbon production enhancement system disclosed in this utility model is as follows:

[0031] The feed gas is refinery hydrogenation tail gas, with a volume of 65,000 Nm³. 3 The pressure is 3.55 MPaG per hour, and its composition is as follows:

[0032] Components <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[C2H4]]> <![CDATA[C3H6]]> <![CDATA[C 4+ ]]> Composition (vol%) 74.00 0.80 9.61 5.50 4.66 5.43

[0033] The feed gas is connected to the heater 1 via feed gas pipeline a. After being heated to 80°C, the feed gas enters the membrane separator 2 via the first pipeline b. The enriched hydrogen gas is connected to the hydrogen product pipeline c via the first permeate side outlet 201 of the membrane separator 2. After the membrane separation cutoff temperature rise, the 91°C non-permeate gas passes through the first retrieval side outlet 202 of the membrane separator 2, sequentially through the second pipeline d, the water cooler 3, and the third pipeline e, and exchanges heat with the gas-to-gas heat exchanger 4. The non-permeate gas then passes through the gas-to-gas heat exchanger 4 after heat exchange. The first hot stream outlet 401 passes sequentially through the fourth pipeline f, condenser 5, and fifth pipeline g to the gas-liquid separator 6. After separation by the gas-liquid separator 6, the enriched light hydrocarbons are connected to the light hydrocarbon product pipeline h through the first liquid phase outlet 601 of the gas-liquid separator 6 to collect the light hydrocarbon product. Meanwhile, the non-condensable vapors pass through the first gas phase outlet 602 of the gas-liquid separator 6 and enter the gas-gas heat exchanger 4 through the sixth pipeline i. After the non-condensable vapors undergo cooling recovery in the gas-gas heat exchanger 4, they are discharged through the first cold stream outlet 402 of the gas-gas heat exchanger 4 and the exhaust gas pipeline j.

[0034] The volume of hydrogen-rich product gas obtained after membrane separation is 50121 Nm³. 3 / h is composed of the following:

[0035] Components <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[C2H4]]> <![CDATA[C3H6]]> <![CDATA[C 4+ ]]> Composition (vol%) 94.68 0.50 2.90 1.45 0.33 0.14

[0036] The volume of liquid light hydrocarbon product gas obtained through the membrane separator and condensation process is 8406 Nm³. 3 / h is composed of the following:

[0037] Components <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[C2H4]]> <![CDATA[C3H6]]> <![CDATA[C 4+ ]]> Composition (vol%) 0.50 0.29 12.82 19.78 27.72 38.89

[0038] The amount of non-condensable exhaust gas obtained from the condensation process is 6472 Nm³. 3 / h is composed of the following:

[0039] Components <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[C2H4]]> <![CDATA[C3H6]]> <![CDATA[C 4+ ]]> Composition (vol%) 9.31 3.78 57.41 18.30 8.23 2.97

[0040] After membrane separation and condensation, 98.66% of hydrogen and 85.38% of light hydrocarbons (C2 and above components) can be recovered from the feed gas, resulting in significant economic benefits.

[0041] This application utilizes a high-temperature resistant membrane separator to recover hydrogen on the permeate side while simultaneously achieving the highest possible hydrocarbon dew point on the non-permeate side. A higher hydrocarbon dew point results in a higher condensation recovery rate of downstream light hydrocarbons, thus achieving efficient recovery and utilization of both hydrogen and light hydrocarbons. Furthermore, the gas-to-gas heat exchanger in this system can recover cooling capacity, reduce the load on the condenser and the amount of refrigerant used, thereby further reducing energy consumption.

[0042] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A membrane-based system for hydrogen recovery and light hydrocarbon production enhancement, characterized in that, The system includes a heater (1), a membrane separator (2), a water cooler (3), a gas-to-gas heat exchanger (4), a condenser (5), and a gas-liquid separator (6) connected in sequence. One end of the heater (1) is provided with a raw material gas pipeline (a); The membrane separator (2) is equipped with a hydrogen product pipeline (c); One end of the gas-liquid separator (6) is provided with a light hydrocarbon product pipeline (h).

2. The membrane-based hydrogen recovery and light hydrocarbon production system according to claim 1, characterized in that, The system also includes a first pipeline (b), a second pipeline (d), a third pipeline (e), a fourth pipeline (f), a fifth pipeline (g), a sixth pipeline (i), and an exhaust gas pipeline (j); The heater (1) is connected to the membrane separator (2) via a first pipeline (b), the membrane separator (2) is connected to the water cooler (3) via a second pipeline (d), the water cooler (3) is connected to the gas-to-gas heat exchanger (4) via a third pipeline (e), the gas-to-gas heat exchanger (4) is connected to the condenser (5) via a fourth pipeline (f), and the condenser (5) is connected to the gas-liquid separator (6) via a fifth pipeline (g). The gas-to-gas heat exchanger (4) is equipped with a gas discharge pipeline (j).

3. The membrane-based hydrogen recovery and light hydrocarbon production system according to claim 2, characterized in that, The system also includes a first permeation-side outlet (201), a first interception-side outlet (202), a first hot flow outlet (401), a first cold flow outlet (402), a first liquid phase outlet (601), and a first gas phase outlet (602). The first permeate-side outlet (201) is located at the connection between the membrane separator (2) and the hydrogen product pipeline (c); The first interception side outlet (202) is located at the connection between the membrane separator (2) and the second pipeline (d); The first hot flow outlet (401) is located at the connection between the gas-to-gas heat exchanger (4) and the fifth pipeline (f); The first cold flow outlet (402) is located at the connection between the gas-to-gas heat exchanger (4) and the exhaust gas pipeline (j); The first liquid phase outlet (601) is located at the connection between the gas-liquid separator (6) and the light hydrocarbon product pipeline (h); The first gas phase outlet (602) is located at the connection between the gas-liquid separator (6) and the sixth pipeline (i).

4. The membrane-based hydrogen recovery and light hydrocarbon production system according to claim 3, characterized in that, The dew point temperature of the first retrieval outlet (202) of the membrane separator (2) is not lower than 80°C.

5. The membrane-based hydrogen recovery and light hydrocarbon production system according to claim 1, characterized in that, The membrane separator (2) has a temperature resistance of not less than 90°C.

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