Integrated device for purifying hydrogen from refinery hydrogen-containing dry gas

Abstract

The utility model discloses an integrated device for purifying hydrogen from refinery hydrogen-containing dry gas. The integrated device comprises a raw material gas treatment unit, a temperature swing adsorption unit, a membrane separation treatment unit and a pressure swing adsorption unit which are connected in sequence. The membrane separation, pressure swing adsorption and temperature swing adsorption are combined by mainly adopting a coupling process technical scheme which takes a membrane separation technology as a main technology and takes temperature swing adsorption and pressure swing adsorption as an auxiliary technology, so that the membrane separation, pressure swing adsorption and temperature swing adsorption are combined, and the membrane separation, pressure swing adsorption and temperature swing adsorption device has the advantages of small investment, small occupied area, flexibility in operation and the like. And after the catalytic hydrogen-containing dry gas is purified, the hydrogen purity of the product is 99.5 V% or above, and the hydrogen recovery rate is not less than 85%.

Description

Technical Field

[0001] The utility model relates to a hydrogen purification device, in particular to an integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery. Background Art

[0002] Refinery hydrogenated dry gas originates from secondary crude oil processing, such as catalytic cracking and delayed coking. Hydrogenated dry gas from catalytic cracking of wax oil typically contains approximately 25% hydrogen, while hydrogenated dry gas from catalytic cracking of heavy oil or residual oil typically contains 40% to 60% hydrogen. Currently, catalytic hydrogenated dry gas is primarily burned as fuel, making it of low utility value. Therefore, recovering and purifying the hydrogen present in this gas is crucial for fully utilizing catalytic hydrogenated dry gas resources and developing hydrogenation processes, with significant economic and social benefits.

[0003] Currently, relatively mature and widely used hydrogen purification and recovery technologies include cryogenic separation, pressure swing adsorption, and membrane separation. Cryogenic separation utilizes the relative volatility differences among different components in the feed gas to separate and purify hydrogen. Cryogenic separation processes are costly, lack flexibility in handling different feed compositions, and sometimes require supplemental refrigeration. They are therefore suitable for purification processes with relatively low hydrogen contents and the need to recover and separate multiple products. Pressure swing adsorption technology can reduce operating costs and investment in hydrogen purification processes, improve the performance of pressure swing adsorption units, and enhance their technological content and competitiveness. This opens up new avenues for the separation and purification of hydrogen-containing gas sources and the comprehensive utilization of waste gases in my country's petrochemical industry, playing a positive role in improving the petrochemical industry's product mix, enhancing the comprehensive utilization of refinery mixed gases, and improving overall economic benefits. Regarding membrane separation, selecting an appropriate membrane separation process can replace various traditional separation and filtration methods, such as distillation and evaporation, vacuum filtration, concentration and extraction, and ion exchange. This addresses the challenges of high energy consumption, poor quality, low yield, and heavy pollution that currently plague the industrial production of certain products using traditional processes. Utility Model Content

[0004] The utility model provides an integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery, which is used for purifying and recovering hydrogen components in the hydrogen-containing dry gas in the refinery. The utility model mainly adopts a coupled process technology scheme based on membrane separation technology, supplemented by temperature swing adsorption oil removal and purification, and pressure swing adsorption. The catalytic hydrogen-containing dry gas is first pretreated by temperature swing adsorption to remove heavy hydrocarbon components; the raw gas after removal is sent to the membrane separation part; the separated permeate gas is further purified by pressure swing adsorption to achieve the target purity of the product hydrogen, and the product hydrogen is directly sent to the hydrogen pipeline network, and the tail gas is incorporated into the fuel gas system as fuel.

[0005] Specifically, an integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery includes a feed gas processing unit, a temperature swing adsorption unit, a membrane separation processing unit, and a pressure swing adsorption unit that are connected in sequence.

[0006] The feed gas processing unit consists of a feed gas compressor, a feed gas cooler, and a feed gas gas-liquid separator, all connected in sequence via pipelines. The feed gas compressor's inlet is connected to the refinery's hydrogen-containing dry gas supply unit. The feed gas gas-liquid separator's outlet is connected to the temperature swing adsorption unit.

[0007] The temperature swing adsorption unit comprises at least one temperature swing adsorption tower. The outlet of the feed gas-liquid separator is connected to the bottom of the temperature swing adsorption tower via a pipeline, allowing gas to enter the tower from the bottom. In one embodiment, the temperature swing adsorption unit comprises two or more temperature swing adsorption towers, connected by pipelines and valves. The valves are controlled to enable the two or more temperature swing adsorption towers to be connected in parallel. Thus, during the process, the valves can be controlled to switch between operation and regeneration standby. One temperature swing adsorption tower operates until saturation, while the remaining towers are regenerated or kept in standby.

[0008] The membrane separation treatment unit includes a gas-liquid separator, a coalescing separation filter, a feed heater, a primary membrane separation device, a secondary membrane separation device, and a cooler. The gas-liquid separator, coalescing separation filter, feed heater, primary membrane separation device, and secondary membrane separation device are connected in sequence. The gas outlets on the membrane permeate sides of the primary and secondary membrane separation devices are connected to the coolers, and the gas outlets of the coolers are connected to the pressure swing adsorption unit.

[0009] The non-permeable membrane side of the primary membrane separation unit is connected to the non-permeable membrane side of the secondary membrane separation unit. The non-permeable membrane side of the secondary membrane separation unit is connected to the top of the thermal swing adsorption tower via piping and a thermal swing adsorption regeneration heater. During the process, the gas from the non-permeable membrane side of the secondary membrane separation unit is used to regenerate and cool the thermal swing adsorption tower, and is ultimately incorporated into the plant's fuel gas network.

[0010] The pressure swing adsorption unit includes a hydrogen-rich gas compressor, a hydrogen-rich gas cooler, a hydrogen-rich gas buffer tank, and at least one pressure swing adsorption tower, all connected in sequence. The top outlet of each pressure swing adsorption tower is connected to the hydrogen buffer tank, while the bottom outlet is connected to the desorbed gas buffer tank. The top outlet of the desorbed gas buffer tank is connected to the desorbed gas compressor.

[0011] The number of the pressure swing adsorption towers is more than two, connected by pipes and valves, and the adsorption towers are connected in parallel by controlling the valves. The top gas outlets of all the pressure swing adsorption towers are connected to the hydrogen buffer tank, and the bottoms are connected to the desorption gas buffer tank.

[0012] There are two hydrogen buffer tanks, one for low-pressure downstream hydrogen buffer tank and one for high-pressure downstream hydrogen buffer tank. The gas outlets of the two hydrogen buffer tanks are also connected to the pressure swing adsorption tower, and the pressure swing adsorption tower is flushed with purified hydrogen.

[0013] Beneficial effects of the utility model:

[0014] This utility model primarily utilizes a coupled process technology solution based on membrane separation, supplemented by temperature swing adsorption and pressure swing adsorption. This combination of membrane separation, pressure swing adsorption, and temperature swing adsorption offers advantages such as low investment, minimal footprint, and flexible operation. The purified catalytic hydrogen-containing dry gas produces hydrogen with a purity exceeding 99.5% by volume, and a hydrogen recovery rate of at least 85%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of an integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery. DETAILED DESCRIPTION

[0016] The present invention will be further described below through the following specific implementations, but the content of the present invention is not limited thereto.

[0017] like Figure 1 As shown, the integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery comprises a feed gas processing unit, a temperature swing adsorption unit, a membrane separation processing unit and a pressure swing adsorption unit which are connected in sequence.

[0018] The feed gas processing unit consists of a feed gas compressor 2, a feed gas cooler 3, and a feed gas gas-liquid separator 4, all connected in sequence via pipelines. The air inlet of the feed gas compressor 2 is connected to the refinery's hydrogen-containing dry gas supply unit. The temperature swing adsorption unit comprises two parallel-connected temperature swing adsorption towers 5: a first temperature swing adsorption tower and a second temperature swing adsorption tower. These towers can be switched between operation and regeneration standby via control valves. One temperature swing adsorption tower operates until saturated, while the other regenerates. The outlet of the feed gas gas-liquid separator 4 is connected to the bottom of the temperature swing adsorption tower 5 via a pipeline, allowing gas to enter the temperature swing adsorption tower 5 from the bottom of the tower.

[0019] The membrane separation treatment unit includes a gas-liquid separator 6, a coalescing separation filter 7, a feed heater 8, a primary membrane separation device 9, a secondary membrane separation device 10, and a cooler 12. The gas-liquid separator 6, the coalescing separation filter 7, the feed heater 8, the primary membrane separation device 9, and the secondary membrane separation device 10 are connected in sequence, and the gas outlets on the permeation side of the primary membrane separation device 9 and the secondary membrane separation device 10 are respectively connected to the cooler 12. The hydrogen-rich gas from the permeation side of the primary membrane separation device 9 and the secondary membrane separation device 10 is cooled in the cooler 12, then enters the hydrogen-rich gas compressor 13 for compression and the hydrogen-rich gas cooler 14 for cooling, and is then buffered in the hydrogen-rich gas buffer tank 15.

[0020] The non-permeable membrane side of the primary membrane separation unit 9 is connected to the non-permeable membrane side of the secondary membrane separation unit 10. The non-permeable membrane side of the secondary membrane separation unit 10 is connected to the thermal swing adsorption tower 5 via piping and a thermal swing adsorption regeneration heater 11. During the process, the gas from the non-permeable membrane side of the secondary membrane separation unit 10 is used to regenerate and cool the thermal swing adsorption tower 5, and is ultimately incorporated into the plant's fuel gas network.

[0021] The pressure swing adsorption unit includes a hydrogen-rich gas compressor 13, a hydrogen-rich gas cooler 14, a hydrogen-rich gas buffer tank 15 and eight pressure swing adsorption towers 16 connected in sequence. The eight pressure swing adsorption towers 16 are connected by pipes and valves, and the adsorption towers are connected in parallel by controlling the valves. The top air outlets of the eight pressure swing adsorption towers 16 are all connected to the hydrogen buffer tank 17, and the bottoms are connected to the desorption gas buffer tank 18. The top air outlet of the desorption gas buffer tank 18 is connected to the desorption gas compressor 19. The hydrogen buffer tank 17 has two, one is a low-pressure hydrogen buffer tank, and the other is a high-pressure hydrogen buffer tank. The air outlets of the two hydrogen buffer tanks 17 are also connected to the pressure swing adsorption tower 16, and the pressure swing adsorption tower 16 is flushed with purified hydrogen.

[0022] In this embodiment, the purification of hydrogen from the hydrogen-containing dry gas in the refinery is divided into four process steps according to the process, namely compression, temperature swing adsorption, membrane separation, and pressure swing adsorption.

[0023] (1) Raw gas compression and pressure boosting

[0024] The catalytic hydrogen-containing dry gas is pressurized to 3.0 MPaG through the raw gas compressor 2, and then enters the raw gas cooler 3 and the raw gas gas-liquid separator 4 in sequence for condensation and liquid separation, and then enters the temperature swing adsorption tower 5 for oil removal and purification process.

[0025] (2) Temperature swing adsorption

[0026] The compressed and condensed catalytic hydrogen-containing dry gas directly enters the temperature swing adsorption oil removal purification process composed of two parallel temperature swing adsorption towers 5, and the obtained purified gas enters the membrane separation unit for the membrane separation process.

[0027] The two temperature swing adsorption towers 5 are switched between operation and regeneration standby via control valves. One temperature swing adsorption tower 5 operates until saturation, while the other regenerates. The catalytic hydrogen-containing dry gas is selectively adsorbed by the adsorbent, which selectively adsorbs hydrocarbons and impurities above C2 that are difficult to desorb. The adsorbent is then fed to the membrane separation system. The saturated adsorbent is then heated and purged using the non-permeate gas from the subsequent membrane separation process. The regenerated non-permeate gas is then discharged to the fuel gas network.

[0028] Temperature swing adsorption procedure: Step 1: adsorption; Step 2: reverse depressurization; Step 3: heating and desorption; Step 4: cooling; Step 5: pressurization.

[0029] Normal production conditions: temperature swing adsorption pressure 3.0MPaG, temperature swing adsorption temperature ≯30℃.

[0030] Regeneration conditions: pressure drops from 3.0 MPaG to 0.7 MPaG, regeneration temperature is above 140°C, time is 2 hours, cooling to room temperature, charging pressure from 0.7 MPaG to 3.0 MPaG.

[0031] The above steps complete the normal production and regeneration switching. The adsorption and regeneration processes of the two temperature-swing adsorption towers are all controlled by multiple program-controlled valves according to the designed program. During the entire adsorption and regeneration process, controlling the temperature of the regeneration gas is the key.

[0032] Specific steps:

[0033] 1) Adsorption: The 3.0 MPaG feed gas enters the first temperature swing adsorption tower in the adsorption process, enters from the lower inlet of the temperature swing adsorption tower, and passes through the adsorption zone from bottom to top. The adsorption temperature is ≤ 30°C. Under the selective adsorption action of the adsorbent, impurities such as oil, water, and heavy hydrocarbons in the hydrogen-containing dry gas are adsorbed. The purified gas after oil removal is discharged from the top of the tower and enters the next process.

[0034] 2) Reverse Depressurization: When the first temperature swing adsorption tower reaches a preset adsorption time and the adsorbent in the adsorption zone approaches saturation, the second temperature swing adsorption tower is switched to operation. The adsorption zone of the first temperature swing adsorption tower is reversely depressurized to atmospheric pressure to partially desorb the adsorbed impurities.

[0035] 3) Desorption by heating: When the pressure of the first temperature swing adsorption tower drops to normal pressure, the permeate gas separated from the membrane is heated by the regeneration heater and then enters directly from the top of the first temperature swing adsorption tower, heating the adsorbent in the tower from top to bottom, so that the temperature of the adsorbent increases. As the temperature increases, the heavy components adsorbed by the adsorbent are gradually desorbed and carried out of the first temperature swing adsorption tower by the non-permeate gas; finally, the outlet temperature of the first temperature swing adsorption tower is raised to above 140°C and maintained for about 2 hours to allow it to be regenerated completely; after regeneration, the non-permeate gas is discharged to the fuel gas pipeline network.

[0036] 4) Cooling: After completing the third step, the permeate gas separated from the membrane is directly blown to cool the adsorbent in the first temperature swing adsorption tower without being heated, and finally the adsorbent bed temperature of the first temperature swing adsorption tower is reduced to room temperature. After regeneration, the non-permeate gas is discharged to the fuel gas pipeline network.

[0037] 5) Pressurization: After the cooling process is completed, the first temperature swing adsorption tower can basically carry out the adsorption and oil removal work, but the pressure is low. Directly incorporating it into the system will cause large pressure fluctuations in the system. At this time, the purified gas after purification at the outlet of the second temperature swing adsorption tower is used to slowly pressurize the first temperature swing adsorption tower, and the pressure eventually rises to the normal working pressure (3.0MPaG), preparing for the next purification work.

[0038] The above completes a complete regeneration process, and the two temperature-swing adsorption towers perform adsorption and regeneration alternately to achieve the purpose of continuous operation.

[0039] (3) Membrane separation process

[0040] The membrane separation process is mainly divided into two parts: gas pretreatment and membrane separation.

[0041] 1) Gas pretreatment

[0042] The purified gas from the temperature swing adsorption unit first passes through the gas-liquid separator 6 to remove suspended solid-liquid particles and liquid oil droplets in the gas. It then enters the coalescing separation filter to remove particulate matter and residual oil. It is then heated to 50-55°C by the feed heater 8 and delivered to the primary membrane separation device 9. The purpose of pretreatment is to ensure the cleanliness of the gas entering the membrane, thereby ensuring the long-term stable operation of the membrane separation device.

[0043] In this embodiment, the coalescing separation filters 7 are connected in series in two groups to perform two-stage filtration on the purified gas. Of course, each group is provided with two coalescing separation filters 7 for alternate use to achieve the purpose of continuous operation.

[0044] 2) Membrane separation

[0045] After being purified by temperature swing adsorption (TSA), the raw catalytic hydrogen-containing dry gas meets membrane entry requirements and enters the primary membrane separation unit 9. Driven by the pressure differential, the hydrogen with the faster permeation rate is enriched on the permeation side due to the different permeation rates of the components. The hydrogen-rich gas, with a hydrogen concentration of ≥80% and a pressure of approximately 0.4 MPaG, is sent to the hydrogen-rich compressor 13 for pressure increase to 2.5 MPaG. It is then condensed to 35-40°C by the hydrogen-rich cooler 14 and sent to the hydrogen-rich buffer tank 15 for liquid separation. After liquid separation, it enters the pressure swing adsorption unit for hydrogen purification. The non-permeate gas separated by the primary membrane separation unit 9, at a pressure of approximately 2.9 MPaG, continues to enter the secondary membrane separation unit 10 for hydrogen recovery, thereby increasing the membrane separation hydrogen recovery rate to 85%. The hydrogen-rich gas separated by the secondary membrane separation unit 10, at a pressure of approximately 0.4 MPaG, is sent to the hydrogen-rich compressor 13 for pressure increase along with the hydrogen-rich gas from the primary membrane separation unit 9. The non-permeate gas separated by the secondary membrane separation device 10 has a pressure of about 2.9 MPaG and is used for regeneration and cooling of the temperature swing adsorption tower. It is finally reduced in pressure to 0.7 MPaG and incorporated into the fuel gas network within the plant.

[0046] (4) Pressure swing adsorption (PSA)

[0047] The PSA process includes hydrogen-rich gas compression, pressure swing adsorption (PSA) and desorption gas compression

[0048] 1) Hydrogen-rich gas compression

[0049] The hydrogen-rich gas recovered from the membrane separation unit is pressurized to 2.5 MPaG by the hydrogen-rich gas compressor 13 and cooled to 40° C. by the hydrogen-rich gas cooler 14 , and enters the hydrogen-rich gas buffer tank 15 for liquid separation. After liquid separation, it enters the pressure swing adsorption tower 16 .

[0050] 2) Pressure swing adsorption, mainly composed of adsorption and regeneration procedures

[0051] The hydrogen-rich gas after compression and pressure increase is cooled and separated, and then directly enters the pressure swing adsorption tower 16 for pressure swing adsorption purification to purify the hydrogen. The pressure swing adsorption (PSA) process adopts an 8-1-5 flushing process, that is, the device is composed of 8 pressure swing adsorption towers 16, one of which is always in the feed adsorption state, while one pressure swing adsorption tower 16 is in the continuous flushing stage, and the remaining 6 pressure swing adsorption towers 16 are in different stages of regeneration. The process consists of adsorption, five equalization pressure drops, forward placement, reverse placement, flushing, five equalization pressure increases, and final product pressure increase. The process is explained using a pressure swing adsorption tower as an example, as follows:

[0052] A. Adsorption process

[0053] The pressure of the hydrogen-rich gas from the hydrogen-rich gas compressor 13 is about 2.5 MPaG, and the temperature is 40-45°C. The hydrogen-rich gas first passes through the hydrogen-rich gas cooler 14 to reduce the temperature of the hydrogen-rich gas to below 40°C, and then enters the hydrogen-rich gas buffer tank 15 to separate the droplets. The dry gas comes out of the hydrogen-rich gas buffer tank 15 and enters the bottom of the pressure swing adsorption tower 16. The gas passes through the adsorption bed from bottom to top. The methane, nitrogen, CO, CO2 and a small amount of heavy hydrocarbons in the gas are adsorbed by the adsorbent in the tower. Hydrogen and other components are continuously discharged from the top of the pressure swing adsorption tower 6 to the product hydrogen buffer tank 17, and the pressure is reduced to 1.0 MPaG and sent out of the boundary.

[0054] When the front of the mass transfer zone of the adsorbed impurities (called the adsorption front) reaches a certain position in the reserved section of the bed outlet, the raw gas feed valve and the product gas outlet valve of the pressure swing adsorption tower 16 are closed, the adsorption is stopped, and the regeneration process begins.

[0055] B. The regeneration process of the adsorbent is as follows:

[0056] a. Pressure equalization and pressure reduction process

[0057] This is the process of transferring the higher-pressure hydrogen in the tower into other lower-pressure adsorption towers that have completed regeneration along the adsorption direction after the adsorption process is completed. This process is not only a pressure reduction process, but also a process of recovering hydrogen in the dead space of the bed. It includes a total of 5 consecutive equalization and pressure reduction processes to ensure the full recovery of hydrogen.

[0058] The pressure dropped from 2.5MPaG to 0.45MPaG, and the process is as follows: the first level dropped by 2.5MPaG→2.09MPaG; the second level dropped by 2.09MPaG→1.68MPaG; the third level dropped by 1.68MPaG→1.27MPaG; the fourth level dropped by 1.27MPaG→0.86MPaG; the fifth level dropped by 0.86MPaG→0.45MPaG.

[0059] b. Sequential release process

[0060] During this process, pure hydrogen is discharged from the upper portion of the pressure swing adsorption tower 16 into the hydrogen buffer tank 17 along the adsorption direction. This portion of hydrogen is buffered and used as flushing gas for the subsequent pressure swing adsorption tower 16. The hydrogen buffer tank 17 has two components: a low-pressure downstream hydrogen buffer tank and a high-pressure downstream hydrogen buffer tank.

[0061] During this process, the pressure drops from 0.45 MPaG to 0.18 MPaG, and the process is as follows: Sequential release 1: 0.45 MPaG → 0.31 MPaG; Sequential release 2: 0.31 MPaG → 0.18 MPaG. Sequential release 1 is high-pressure sequential release, and sequential release 2 is low-pressure sequential release.

[0062] c. Reverse process

[0063] After the forward discharge is completed and the adsorption front has reached the bed outlet, the pressure of the pressure swing adsorption tower 16 is reduced to near atmospheric pressure in the opposite direction of adsorption. At this time, the adsorbed impurities begin to be desorbed from the adsorbent in large quantities and enter the desorbed gas buffer tank 18 for buffering. The desorbed gas buffer tank 18 includes a reverse discharge buffer tank and a desorbed gas mixing tank. That is, the desorbed gas is buffered in two stages, namely, the reverse discharge buffer tank and the desorbed gas mixing tank. After the pressure is stabilized, it is directly sent to the desorbed gas compressor inlet 19.

[0064] During this process, the pressure is: 0.18MPaG→0.02MPaG.

[0065] d. Flushing process

[0066] In this process, the pressure swing adsorption tower 16 is flushed with hydrogen in the forward-discharging hydrogen buffer tank 17 in the opposite direction of adsorption, so that the impurities adsorbed by the adsorbent can be completely desorbed under the flushing conditions of hydrogen. The flushed gas is sent to the desorption gas buffer tank 18 for buffering and then sent to the inlet of the desorption gas compressor 19. Considering that the impurity content of the adsorbent is relatively high during regeneration flushing, a continuous flushing process is designed. After each adsorption tower is reversed, it is continuously flushed for one adsorption cycle (about 3.5 minutes) to make the desorption of the adsorbent more thorough, so as to ensure the high impurity content requirements of this device. The flushing process is divided into two stages. The first stage uses the gas in the low-pressure forward-discharging hydrogen buffer tank for flushing (P2), and the second stage uses the gas in the high-pressure forward-discharging hydrogen buffer tank for flushing (P1).

[0067] e. Voltage equalization and boosting process

[0068] After the adsorbent is flushed and regenerated, the pressure equalizing valves of each pressure swing adsorption tower 16 are opened sequentially, and the dead space gas from the other pressure swing adsorption towers is used to equalize the pressure of the pressure swing adsorption tower 16. During this process, the pressure of the pressure swing adsorption tower 16 gradually increases, and hydrogen and other components are recovered from these towers. The entire pressure equalization process consists of five consecutive pressure equalization steps (abbreviated as "equalization steps").

[0069] The equalization pressure increasing process: the pressure increases from 0.02MPaG to 2.5MPaG, and the process is as follows: the first equalization pressure increases by 0.02MPaG→0.45MPaG; the second equalization pressure increases by 0.45MPaG→0.86MPaG; the third equalization pressure increases by 0.86MPaG→1.27MPaG; the fourth equalization pressure increases by 1.27MPaG→1.68MPaG; the fifth equalization pressure increases by 1.68MPaG→2.09MPaG; and the final equalization pressure increases by 2.09MPaG→2.5MPaG.

[0070] f. Product gas pressure boosting process

[0071] After the five equalization and pressure-raising processes are completed, in order to enable the pressure swing adsorption tower 16 to smoothly switch to the next adsorption and ensure that the product purity does not fluctuate during this process, it is necessary to slowly and steadily use the product hydrogen through the pressure-boosting regulating valve to increase the pressure of the pressure swing adsorption tower 16 to the adsorption pressure index. After this, a complete cycle process is completed and the next adsorption cycle can be entered.

[0072] In this way, 8 adsorption towers perform the above adsorption and regeneration operations alternately, that is, there is always one adsorption tower in the adsorption state, one adsorption tower in the continuous flushing state, and the remaining 6 adsorption towers are in different stages of regeneration, so that continuous separation and purification of the gas can be achieved.

[0073] 3) Decompression of the inhaled gas

[0074] The desorbed gas from the pressure swing adsorption tower 16 needs to be pressurized to 0.7 MPaG by the desorbed gas compressor 19 and returned to the fuel gas pipeline network in the factory.

Claims

1. An integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery, characterized by: It includes a raw gas processing unit, a temperature swing adsorption unit, a membrane separation processing unit and a pressure swing adsorption unit connected in sequence; The raw gas processing unit includes a raw gas compressor, a raw gas cooler, and a raw gas gas-liquid separator connected in sequence through pipelines, the air inlet of the raw gas compressor is connected to the refinery's hydrogen-containing dry gas supply unit, and the air outlet of the raw gas gas-liquid separator is connected to the temperature swing adsorption unit; The temperature swing adsorption unit is at least one temperature swing adsorption tower, the gas outlet of the feed gas-liquid separator is connected to the bottom of the temperature swing adsorption tower through a pipeline, and the gas enters the temperature swing adsorption tower from the bottom of the tower; The temperature swing adsorption unit comprises two or more temperature swing adsorption towers, which are connected by pipes and valves, and the valves are controlled so that the two or more temperature swing adsorption towers are connected in parallel; The membrane separation treatment unit includes a gas-liquid separator, a coalescing separation filter, a feed heater, a primary membrane separation device, a secondary membrane separation device and a cooler. The gas-liquid separator, the coalescing separation filter, the feed heater, the primary membrane separation device and the secondary membrane separation device are connected in sequence. The gas outlets on the membrane permeation sides of the primary membrane separation device and the secondary membrane separation device are respectively connected to the cooler, and the gas outlet of the cooler is connected to the pressure swing adsorption unit.

2. The integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery according to claim 1, characterized in that: The non-permeable membrane side of the primary membrane separation device is connected to the non-permeable membrane side of the secondary membrane separation device, and the non-permeable membrane side of the secondary membrane separation device is connected to the top of the temperature swing adsorption tower through a pipeline and the temperature swing adsorption regeneration heater.

3. The integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery according to claim 1, characterized in that: The pressure swing adsorption unit includes a hydrogen-rich gas compressor, a hydrogen-rich gas cooler, a hydrogen-rich gas buffer tank and at least one pressure swing adsorption tower connected in sequence; the top gas outlets of the pressure swing adsorption towers are connected to the hydrogen buffer tank, and the bottoms are connected to the desorption gas buffer tank; the top gas outlet of the desorption gas buffer tank is connected to a desorption gas compressor.

4. The integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery according to claim 3, characterized in that: There are more than two pressure swing adsorption towers, which are connected by pipes and valves, and the adsorption towers are connected in parallel through the control of the valves; the top outlet of each pressure swing adsorption tower is connected to the hydrogen buffer tank, and the bottom is connected to the desorption gas buffer tank.

5. The integrated device for purifying hydrogen from hydrogen-containing dry gas in a refinery according to claim 3, characterized in that: There are two hydrogen buffer tanks, one is a low-pressure hydrogen buffer tank, and the other is a high-pressure hydrogen buffer tank. The gas outlets of the low-pressure hydrogen buffer tank and the high-pressure hydrogen buffer tank are also connected to the pressure swing adsorption tower.

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