Treatment method of light hydrocarbon modification reaction product

Abstract

The invention relates to a treatment method of a light hydrocarbon modification reaction product. The method comprises the following steps: 1) compressing and separating a light hydrocarbon modification reaction product to obtain compressed gas and compressed hydrocarbon liquid; (2) the compressed gas is subjected to membrane separation after being decompressed and heated, and a permeable phase rich in hydrogen and methane and a non-permeable phase rich in propane gas are obtained; 3) carrying out absorption and desorption treatment on the impermeable phase and / or the compressed hydrocarbon liquid to obtain a propane-rich liquid; and 4) enriching and recovering propane in the propane-rich liquid. Light hydrocarbon modification, membrane separation and absorption and desorption technologies are coupled, through comprehensive pressure and temperature regulation measures, the composition of membrane separation inlet gas is adjusted, the dew point of the membrane separation inlet gas is improved, the partial pressure of heavy components in the membrane separation inlet gas is reduced, separation of a membrane separation impermeable phase is avoided, normal operation of a membrane separation assembly is guaranteed, and the membrane separation efficiency is improved. Furthermore, the propane loss is reduced, and the energy consumption is saved.

Description

Technical Field

[0001] The present invention relates to a method for treating the product of a light hydrocarbon reforming reaction. Background Art

[0002] Light hydrocarbon reforming is a technology that uses C4 and higher alkanes as raw materials to produce propane and aromatics. This technology can highly selectively convert the industrially abundant C4 and C5 alkanes and heavier C6 alkanes into propane and aromatics. Propane provides a cost - effective raw material for propane dehydrogenation units, and through further separation, aromatics can obtain organic raw materials such as benzene, toluene, and xylene. The sources of light hydrocarbons are very wide. For example, light oils, condensate oils, stabilized light hydrocarbons, naphthas, topped oils, and petroleum ethers by - produced from oil and gas fields and refineries mainly consist of C5 alkanes. At the same time, the production capacity of propane dehydrogenation units in China is huge, and it is necessary to further enrich the raw material sources to avoid large fluctuations in raw material prices. Through the light hydrocarbon reforming unit, a large amount of surplus light hydrocarbon resources are reformed into propane and aromatics, which not only improves the added value of light hydrocarbon raw materials but also solves the problem of raw material sources for propane dehydrogenation units, having good economic benefits.

[0003] CN 113307717B proposes a method for producing propane by hydro - light hydrocarbon conversion. This method obtains a relatively high single - pass stability of the catalyst, a relatively low dry gas yield, and a relatively high propane yield through a large - scale circulation of hydrogen - rich gas (the hydrogen - to - oil ratio of hydrogen - rich gas and reaction feed is 30 - 800). The examples of this method reveal the separation method of the reaction product. The hydrogen - rich gas and propane and heavier components are separated by an absorption - desorption method. After the hydrogen - rich gas further recovers propane in a re - absorption tower, it enters the hydrogen recovery unit to obtain recycled hydrogen. The absorbent of the absorption tower comes from the stabilized gasoline at the bottom of the stabilizer, and its components are C5 and heavier components in the reaction product.

[0004] CN 110951500B proposes a method for producing propane and gasoline from alkanes. This method uses one or more of C5 - C12 alkanes as raw materials and produces propane and high - octane gasoline blending components under non - hydrogen - containing conditions. The disclosed method reveals the separation of dry gas through an absorption - desorption tower, and then the separation of liquefied gas rich in propane and high - octane gasoline blending components in a stabilizer.

[0005] The prior art uses the absorption - desorption method to separate hydrogen - rich dry gas instead of the distillation method because hydrogen is a non - condensable gas with an extremely low boiling point. If the distillation method is used for separation, a cryogenic device has to be configured, resulting in huge investment. However, the absorption method for removing dry gas also has great disadvantages. First, due to the high hydrogen content, in order to obtain a relatively high propane recovery rate, a relatively large absorption ratio is required, leading to relatively high operating costs and energy consumption of the device. Second, a large amount of loss of absorbent, especially the high - value - added aromatics in it, in the tail gas results in relatively high material consumption of the device and a decline in benefits.

[0006] Therefore, the prior arts all have problems of low propane recovery rate, aromatics in the absorption tail gas, large absorbent loss, and high energy consumption. The present invention specifically solves the above problems. Summary of the Invention

[0007] The object of the present invention is to overcome the problems existing in the prior arts, such as low recovery rate of alkanes (such as propane), large absorbent loss, and high energy consumption, and to provide a method for treating the light hydrocarbon reforming reaction product, which has the advantages of high alkane recovery rate, small absorbent loss, and low energy consumption.

[0008] To achieve the above object, the first aspect of the present invention provides a method for treating the light hydrocarbon reforming reaction product, which comprises the following steps:

[0009] 1) The light hydrocarbon reforming reaction product is separated after compression to obtain compressed gas and compressed hydrocarbon liquid;

[0010] 2) The compressed gas is subjected to pressure reduction, heating, and then membrane separation to obtain a permeate phase rich in hydrogen and methane and a non-permeate phase rich in propane gas;

[0011] 3) The non-permeate phase and / or the compressed hydrocarbon liquid are subjected to absorption and desorption treatment to obtain a propane-rich liquid;

[0012] 4) The propane in the propane-rich liquid is enriched and recovered.

[0013] Through the above technical solution, the present invention has the following advantages:

[0014] The present invention couples the light hydrocarbon reforming, membrane separation, and absorption and desorption technologies. Through comprehensive pressure and temperature control measures, it adjusts the composition of the membrane separation inlet gas, increases the dew point of the membrane separation inlet gas, reduces the partial pressure of the heavier components in the membrane separation inlet gas, avoids the precipitation of the membrane separation non-permeate phase, ensures the normal operation of the membrane separation module, thereby reducing propane loss and saving energy consumption at the same time.

[0015] Description of the Drawings and Explanation of the Reference Numerals

[0016] Figure 1 It is a schematic diagram of the device and process of an embodiment of the present invention;

[0017] Figure 2 It is the process device and flow chart of Comparative Example 1.

[0018] In the figure, 1 is a light hydrocarbon reforming reactor; 2 is a compression unit; 3 is a membrane separation unit; 5 is an absorption tower; 6 is a desorption tower; 7 is a stabilizer; 8 is a depropanizer; 11 is a light hydrocarbon feedstock; 12 is a reaction product; 13 is compressed gas; 14 is compressed hydrocarbon liquid; 15 is methane hydrogen; 16 is propane-rich gas; 17 is absorption tail gas; 18 is absorption liquid; 19 is recycled material; 20 is desorption tower bottom liquid; 21 is desorption tower top gas; 22 is discharged heavy components; 23 is absorbent; 24 is stabilized light hydrocarbon; 25 is propane; 26 is liquefied petroleum gas.

[0019] The process is briefly described as follows: The light hydrocarbon feedstock 11 is converted into a reaction product 12 through the light hydrocarbon reforming reactor 1. The reaction product 12 and a part of the absorption tail gas from the top of the absorption tower are pressurized by the compression unit 2 to obtain compressed gas 13 and compressed hydrocarbon liquid 14. The compressed gas 13 is depressurized through a pressure reducing valve and heated through a heater, and then enters the membrane separation unit 3 to obtain methane hydrogen 15 and propane-rich gas 16. The propane-rich gas 16 is sent to the absorption tower 5, with the heavy components of the stabilizer as the absorbent, and absorption tail gas 17 is obtained from the top of the absorption tower. A part of the absorption tail gas 17 is recycled to the compression unit 2. The absorption tower bottom liquid 18 and the compressed condensate 14 are mixed and then sent to the desorption tower 6. The desorption tower top gas 21 is returned to the absorption tower, and the desorption tower bottom liquid is sent to the stabilizer 7. The stabilized light hydrocarbon 24 and crude aromatics 22 are obtained through separation by the stabilizer 7. The stabilized light hydrocarbon 24 is separated by the depropanizer 8 to obtain propane 25 and liquefied petroleum gas 26. A part of the crude aromatics 22 is returned to the absorption unit 5 as the absorbent 23. Specific embodiments

[0020] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0021] The present invention provides a method for treating a light hydrocarbon reforming reaction product, and the method includes the following steps:

[0022] 1) The light hydrocarbon reforming reaction product is compressed and then separated to obtain compressed gas and compressed hydrocarbon liquid;

[0023] 2) The compressed gas is depressurized, heated, and then subjected to membrane separation to obtain a permeate phase rich in hydrogen and methane and a non-permeate phase rich in propane gas;

[0024] 3) The non-permeate phase and / or the compressed hydrocarbon liquid are subjected to absorption and desorption treatment to obtain propane-rich liquid;

[0025] 4) Enrich and recover propane in the propane-rich liquid.

[0026] The present invention couples light hydrocarbon reforming, membrane separation, and absorption and desorption technologies. Through comprehensive pressure and temperature control measures, the composition of the feed gas for membrane separation is adjusted, the dew point of the feed gas for membrane separation is increased, and the partial pressure of heavier components in the feed gas for membrane separation is reduced, avoiding the precipitation of the non-permeate phase in membrane separation, ensuring the normal operation of the membrane separation module, thereby reducing propane loss and saving energy consumption at the same time.

[0027] According to a preferred embodiment of the present invention, the absorption and desorption treatment includes: first, performing absorption treatment to obtain absorption tail gas and absorption-rich liquid, and then performing desorption treatment on the absorption-rich liquid to obtain desorbed gas and propane-rich liquid.

[0028] According to a preferred embodiment of the present invention, a part of the absorption tail gas is returned to step 1) for compression. The recycle ratio (recycled absorption tail gas / total absorption tail gas at the top of the absorption tower) is adjusted elastically according to specific operating conditions.

[0029] According to a preferred embodiment of the present invention, the desorbed gas is returned to the absorption treatment.

[0030] According to a preferred embodiment of the present invention, the absorption treatment is carried out in an absorption tower, and the operating conditions of the absorption tower include: the operating pressure is 1.0 - 1.5 MPaG, and the temperature is adjusted elastically according to specific operating conditions.

[0031] According to a preferred embodiment of the present invention, the desorption treatment is carried out in a desorption tower, and the operating conditions of the desorption tower include: the operating pressure is 1.3 - 1.8 MPaG, and the temperature is adjusted elastically according to specific operating conditions.

[0032] According to a preferred embodiment of the present invention, the conditions for compression include: the pressure is 1.35 - 2.0 MPaG.

[0033] According to a preferred embodiment of the present invention, the conditions for compression include: the temperature is 35 - 45 °C.

[0034] According to a preferred embodiment of the present invention, the conditions for membrane separation include: the pressure is 1.15 - 1.8 MPaG.

[0035] According to a preferred embodiment of the present invention, the conditions for membrane separation include: the temperature is 50 - 80 °C.

[0036] According to a preferred embodiment of the present invention, the conditions for membrane separation include: the hydrogen recovery rate is not less than 90 v%, and the methane recovery rate is not more than 80 v%. The recovery rate is determined by the design of the membrane separation unit. For example, at the same hydrogen recovery rate, the polyimide membrane has a high selectivity for hydrogen, and the methane recovery rate is relatively low; the polysulfone membrane has a poor selectivity for hydrogen, and the methane recovery rate is relatively high. For the membrane separation unit, generally the hydrogen recovery rate is controlled, and the methane recovery rate cannot be controlled. By using the system method of the present invention, the overall methane recovery rate can be adjusted.

[0037] According to a preferred embodiment of the present invention, the enrichment and recovery include: first, stable separation is carried out to obtain a heavy component and a light component of propane-rich gas, and the light component is further separated into propane and liquefied gas.

[0038] According to a preferred embodiment of the present invention, the heavy component is recycled back to the absorption and desorption treatment as an absorbent. The recycle ratio (absorbent flow rate / total flow rate of the stable tower bottom liquid) is adjusted elastically according to specific working conditions.

[0039] According to a preferred embodiment of the present invention, the stable separation is carried out in a stable tower, and the operating conditions of the stable tower include: the operating pressure is 1.0 - 1.5 MPaG. The temperature is adjusted elastically according to specific working conditions.

[0040] According to a preferred embodiment of the present invention, the further separation of the light component into propane and liquefied gas is carried out in a depropanizer, and the operating conditions of the depropanizer include: the operating pressure is 1.45 - 1.60 MPaG. The temperature is adjusted elastically according to specific working conditions.

[0041] According to a preferred embodiment of the present invention, the light hydrocarbon reforming reaction product contains hydrogen, methane, ethane, propane, benzene, toluene, and xylene.

[0042] According to a preferred embodiment of the present invention, the hydrogen content in the light hydrocarbon reforming reaction product is not less than 40% by volume fraction.

[0043] According to a preferred embodiment of the present invention, the light hydrocarbon reforming reaction product is from the product after the reforming reaction of a light hydrocarbon raw material.

[0044] According to a preferred embodiment of the present invention, the light hydrocarbon raw material contains at least one of butane, pentane, and hexane.

[0045] According to a preferred embodiment of the present invention, the conditions for the reforming reaction include: the reaction temperature is 400 - 500 °C, and the reaction pressure is 0.01 - 0.1 MPaG.

[0046] According to a preferred embodiment of the present invention, the membrane separation uses at least one of a polyimide hollow fiber membrane, a cellulose acetate membrane, and a polysulfone hollow fiber membrane.

[0047] According to a preferred embodiment of the present invention, the compression includes: performing at least three - stage compression in sequence, and the pressure of the subsequent stage of compression is at least 0.4 MPaG higher than the pressure of the previous stage of compression.

[0048] The present invention will be described in detail below through examples.

[0049] Example 1

[0050] A light hydrocarbon feedstock of 29 tons per hour is provided, with its composition (by mass fraction) being 25% butane, 50% pentane, and 25% hexane. It is converted into a light hydrocarbon reforming reaction product in a light hydrocarbon reforming reactor at a reaction temperature of 450°C and a reaction pressure of 0.05 MPaG. The light hydrocarbon reforming reaction product contains (by volume fraction) 42% hydrogen, 18% methane, 9% ethane, 10% propane, 4% benzene, 8% toluene, 4% xylene, and 5% C4 and heavier alkanes. The gaseous reaction product is cooled to 40°C by water cooling and then sent to the inlet buffer tank of the compressor in the compression unit. After gas-liquid separation, the gas phase enters the inlet of the first stage of the compressor. After pressurization, the pressure is increased to 0.3 MPaG. The material at the outlet of the first stage of compression is cooled to 40°C by water cooling and then sent to the first stage gas-liquid separation tank. The gas phase is sent to the inlet of the second stage of the compressor. After pressurization, the pressure is increased to 0.7 MPaG. The material at the outlet of the second stage of compression is cooled to 40°C by water cooling and then sent to the second stage gas-liquid separation tank. The gas phase is mixed with the absorption tail gas with a flow rate of 2 tons per hour from the top of the absorption tower and then sent to the inlet of the third stage of the compressor. After pressurization, the pressure is increased to 1.5 MPaG. The material at the outlet of the third stage of compression is cooled to 40°C by water cooling and then sent to the outlet buffer tank. The compressed condensate from the inlet buffer tank of the compressor, the inter-stage gas-liquid separation tank, and the outlet buffer tank is collected and sent to the upper part of the desorption tower by a pump uniformly. The compressed gas from the outlet buffer tank is depressurized to 1.3 MPaG by a pressure reducing valve and then heated to 65°C with 100°C hot water and then sent to the membrane separation unit. Using a polyimide hollow fiber membrane module, the hydrogen recovery rate of the membrane separation unit is 90%, and the methane recovery rate is 70%. The membrane separation unit obtains about 3.1 tons per hour of methane hydrogen. The non-permeate phase is rich in propane gas with an average molecular weight of 31.06 and a dew point of 59.3°C. The operating temperature is higher than the dew point, and no condensate precipitates in the membrane separation module. The rich propane gas is mixed with the desorbed gas from the top of the desorption tower and then enters the absorption tower. The operating pressure of the absorption tower is 1.12 MPaG, the absorbent flow rate is 67 tons per hour, and the propane recovery rate at the bottom of the absorption tower is 90%. The top of the absorption tower is the absorption tail gas, and 2 tons per hour of the absorption tail gas is returned to the inlet of the third stage of the compressor, and the remaining about 4.3 tons per hour is discharged. The loss of aromatic hydrocarbons in it is 1.5% of the total aromatic hydrocarbons in the reaction product. The operating pressure of the desorption tower is 1.35 MPaG, the bottom temperature is 165°C, and it is heated with 1.1 MPaG steam. The bottom liquid of the desorption tower enters the stabilizer for separation. The operating pressure of the stabilizer is 1.10 MPaG, the bottom temperature is 226°C, and it is heated with 4.0 MPaG steam. The heavy components at the bottom of the stabilizer are divided into two streams, one goes to the absorption tower as the absorbent, and the rest is discharged. The energy consumption of the compression unit, the absorption and desorption unit, and the stabilizer in this example is 86.4 kg of standard oil per ton of reaction product. The consumption of circulating cooling water, electricity, and steam is shown in Table 1 in detail.

[0051] Example 2

[0052] Using the same raw materials and process flow as in Example 1, the flow rate of the absorption tail gas returned to the inlet of the third stage of the compressor at the top of the absorption tower is increased to 3.5 tons per hour. The operating temperature of the membrane separation unit is 65 °C, and about 3.3 tons per hour of methane hydrogen is obtained. The average molecular weight of the non-permeate phase propane-rich gas is 30.95, and the dew point is 57.9 °C. The operating temperature is higher than the dew point, and no condensate is deposited in the membrane separation module. The propane-rich gas and the desorbed gas from the top of the desorption tower are mixed and then enter the absorption tower. The operating pressure of the absorption tower is 1.12 MPaG, the absorbent flow rate is 76 tons per hour, and the propane recovery rate at the bottom of the absorption tower is 91%. The top of the absorption tower is the absorption tail gas, of which 3.5 tons per hour of the absorption tail gas is returned to the inlet of the third stage of the compressor, and the remaining about 4.1 tons per hour is discharged. The amount of aromatic hydrocarbons lost is 1.4% of the total aromatic hydrocarbons in the reaction products. The energy consumption of the compression unit, absorption and desorption unit, and stabilizer tower in this example is 93.7 kg of standard oil per ton of reaction products. The consumption of circulating cooling water, electricity, and steam is shown in Table 1 for details.

[0053] Example 3

[0054] Using the same raw materials and process flow as in Example 1, a polysulfone hollow fiber membrane module is used. The hydrogen recovery rate of the membrane separation module is 90%, and the methane recovery rate is 85%. The operating temperature of the membrane separation unit is 65 °C, and about 3.5 tons per hour of methane hydrogen is obtained. The average molecular weight of the non-permeate phase propane-rich gas is 32.36, and the dew point is 61.6 °C. The operating temperature is higher than the dew point, and no condensate is deposited in the membrane separation module. The propane-rich gas and the desorbed gas from the top of the desorption tower are mixed and then enter the absorption tower. The operating pressure of the absorption tower is 1.12 MPaG, the absorbent flow rate is 63 tons per hour, and the propane recovery rate at the bottom of the absorption tower is 89%. The top of the absorption tower is the absorption tail gas, of which 2 tons per hour of the absorption tail gas is returned to the inlet of the third stage of the compressor, and the remaining about 3.9 tons per hour is discharged. The amount of aromatic hydrocarbons lost is 1.4% of the total aromatic hydrocarbons in the reaction products. The energy consumption of the compression unit, absorption and desorption unit, and stabilizer tower in this example is 83.4 kg of standard oil per ton of reaction products. The consumption of circulating cooling water, electricity, and steam is shown in Table 1 for details.

[0055] Example 4

[0056] Using the same raw materials and process flow as in Example 1, the outlet temperature of the pre-heater before the membrane separation unit is adjusted to 49 °C, and the operating pressure of the membrane separation unit is 1.28 MPaG. The hydrogen recovery rate of the membrane separation module is 90%, and the methane recovery rate is 70%. The operating temperature of the membrane separation unit is 49 °C, and the dew point of the non-permeate phase propane-rich gas is 59.3 °C. Condensate is deposited in the membrane separation module, which easily causes damage to the membrane separation module and a decrease in the propane recovery rate.

[0057] Example 5

[0058] Using the same raw materials and process flow as in Example 3, no pressure relief valve is installed before the membrane separation unit, and the operating pressure of the membrane separation unit is 1.48 MPaG. A polysulfone hollow fiber membrane module is used. The hydrogen recovery rate of the membrane separation module is 90%, and the methane recovery rate is 85%. The operating temperature of the membrane separation unit is 65 °C. The average molecular weight of the non-permeate phase rich in propane gas is 32.26, and the dew point is 65.1 °C. Condensate is separated out from the membrane separation module and the propane recovery rate decreases.

[0059] Example 6

[0060] Using the same raw materials and process flow as in Example 3, but there is no absorption tail gas returning to the compression unit. A polysulfone hollow fiber membrane module is used. The hydrogen recovery rate of the membrane separation module is 90%, and the methane recovery rate is 85%. The operating temperature of the membrane separation unit is 65 °C. The dew point of the non-permeate phase rich in propane gas is 64.3 °C, which is very close to the operating temperature. If the heat preservation is poor or the ambient temperature drops significantly, it is easy for condensate to be separated out, the risk of damage to the membrane separation module is very high, and the propane recovery rate decreases.

[0061] Comparative Example 1

[0062] The process flow diagram is shown in Figure 2 . Using the same raw material conditions as described in Example 1, the same raw material stream is obtained under the same reaction conditions. The reaction product is cooled to 40 °C by water cooling and then sent to the compressor inlet buffer tank of the compression unit. After gas-liquid separation, the gas phase enters the first stage inlet of the compressor, and the pressure is increased to 1.20 MPaG after being pressurized step by step. Water cooling is provided between stages. After collecting the condensate from each stage, it is uniformly pumped to the upper part of the desorption tower. The compressed gas at the compressor outlet and the desorbed gas from the top of the desorption tower are mixed and then enter the absorption tower. The hydrogen volume content of the gas entering the absorption tower is 48.1%. The operating pressure of the absorption tower is 1.12 MPaG, the absorbent flow rate is 128 tons per hour, the liquid-gas molar ratio of the absorption tower is 1.47, and the propane recovery rate at the bottom of the absorption tower is 90%. The absorption tail gas at the top of the absorption tower has a flow rate of 8.1 tons per hour, and the loss of aromatic hydrocarbons in it is 4.2% of the total aromatic hydrocarbons in the reaction product. The operating pressure of the desorption tower is 1.35 MPaG, the bottom temperature is 200 °C, and it is heated by 2.8 MPaG steam. The propane-rich liquid at the bottom of the desorption tower enters the stabilizer for separation. The operating pressure of the stabilizer is 1.10 MPaG, the bottom temperature is 227 °C, and it is heated by 4.0 MPaG steam. The crude aromatic hydrocarbons at the bottom of the stabilizer are divided into two streams, and one stream goes to the absorption tower as the absorbent. The energy consumption of the compression unit, absorption-desorption unit, and stabilizer in this example is 131.4 kg of standard oil per ton of reaction product. The consumption of circulating cooling water, electricity, and steam is shown in Table 1 in detail.

[0063] Table 1

[0064]

[0065] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for treating the product of a light hydrocarbon reforming reaction, characterized in that, the method comprises the following steps: 1) The product of the light hydrocarbon reforming reaction is compressed and then separated to obtain compressed gas and compressed hydrocarbon liquid; 2) The compressed gas is depressurized, heated and then subjected to membrane separation to obtain a permeate phase rich in hydrogen and methane and a non-permeate phase rich in propane gas; 3) The non-permeate phase and / or the compressed hydrocarbon liquid are subjected to absorption and desorption treatment to obtain a propane-rich liquid; 4) The propane in the propane-rich liquid is enriched and recovered.

2. The treatment method according to claim 1, wherein, the absorption and desorption treatment includes: first performing absorption treatment to obtain absorption tail gas and absorption-rich liquid, and then the absorption-rich liquid is subjected to desorption treatment to obtain desorbed gas and propane-rich liquid; preferably, part of the absorption tail gas is returned to step 1) for compression; and / or the desorbed gas is returned to the absorption treatment; more preferably, the absorption treatment is carried out in an absorption tower, and the operating conditions of the absorption tower include: the operating pressure is 1.0 - 1.5 MPaG; and / or the desorption treatment is carried out in a desorption tower, and the operating conditions of the desorption tower include: the operating pressure is 1.3 - 1.8 MPaG.

3. The treatment method according to claim 1 or 2, wherein, the conditions for compression include: the pressure is 1.35 - 2.0 MPaG; and / or the temperature is 35 - 45 °C.

4. The treatment method according to any one of claims 1 - 3, wherein, the conditions for membrane separation include: the pressure is 1.15 - 1.8 MPaG; and / or the temperature is 50 - 80 °C; and / or the hydrogen recovery rate is not less than 90 v%, and the methane recovery rate is not more than 80 v%.

5. The treatment method according to any one of claims 1 - 4, wherein, the enrichment and recovery includes: first performing stable separation to obtain a heavy fraction and a light fraction rich in propane, and the light fraction is further separated into propane and liquefied gas; preferably, the heavy fraction is recycled back to the absorption and desorption treatment as an absorbent; more preferably, the stable separation is carried out in a stabilizer column, and the operating conditions of the stabilizer column include: the operating pressure is 1.0 - 1.5 MPaG; and / or the further separation of the light fraction into propane and liquefied gas is carried out in a depropanizer column, and the operating conditions of the depropanizer column include: the operating pressure is 1.45 - 1.60 MPaG.

6. The treatment method according to any one of claims 1 - 5, wherein, the product of the light hydrocarbon reforming reaction contains hydrogen, methane, ethane, propane, benzene, toluene and xylene, preferably, the hydrogen content in the product of the light hydrocarbon reforming reaction is not less than 40% by volume fraction.

7. The treatment method according to any one of claims 1 - 6, wherein, the product of the light hydrocarbon reforming reaction is from the product after the reforming reaction of a light hydrocarbon raw material, preferably, the light hydrocarbon raw material contains at least one of butane, pentane and hexane.

8. The treatment method according to claim 7, wherein, the conditions for the reforming reaction include: the reaction temperature is 400 - 500 °C, and the reaction pressure is 0.01 - 0.1 MPaG.

9. The treatment method according to any one of claims 1 - 8, wherein, The membrane separation uses at least one of polyimide hollow fiber membranes, cellulose acetate membranes, and polysulfone hollow fiber membranes.

10. According to the treatment method described in any one of claims 1-9, wherein, the compression includes: performing at least three stages of compression in sequence, and the pressure of the latter stage of compression is at least 0.4 MPaG higher than the pressure of the previous stage of compression.

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