A comprehensive recycling process and system for adjusting multiple refinery gas gradients

Abstract

The present invention provides a process and system for adjusting the comprehensive recovery and utilization of multiple refinery gases. In the separation process of the present invention, the coupled processes of hydrogen and light hydrocarbon recovery of multiple refinery gases are relatively independent, so that the hydrogen and light hydrocarbon recovery processes can promote each other and operate independently of each other, solving the problem that the previous recovery process cannot flexibly adjust the operation and selectively recover light hydrocarbons according to the market value of the product because the light hydrocarbon and hydrogen recovery processes are embedded in each other's recovery process many times. Therefore, the process of the present invention can flexibly adjust the product types as the market price of the product fluctuates. The recovery process uses membrane separation technology and compression condensation technology to synchronously bidirectionally enrich the gradient of each logistics stream and recycle the tail gas, which not only greatly improves the separation efficiency and recovery rate, but also reduces the separation energy consumption. At the same time, according to the different hydrogen and light hydrocarbon compositions of the multiple refinery gases, they are classified so that they have better adaptability to the fluctuations in the composition of refinery gases.

Description

Technical Field

[0001] The invention relates to a gas separation and recovery technology, and in particular to a comprehensive recovery and utilization process and system for regulating the gradients of multiple refinery gases. Background Art

[0002] As the trend of crude oil becoming inferior and heavy becomes more and more obvious, and refineries are constantly developing towards large-scale, integrated, base-based and clean directions, in order to achieve the goal of "reducing costs, improving quality and increasing efficiency" for enterprises, how to efficiently utilize the high-value hydrogen and light hydrocarbon resources in refinery gas has become the focus of attention and research in the refining industry. At present, most refineries' refinery gas rich in hydrogen and light hydrocarbons is usually used as fuel gas, and hydrogen and light hydrocarbons are important raw materials in processes such as hydrogenation and liquefied gas production. From the perspective of chemical thermodynamics, the heat absorbed by the hydrogen component from room temperature to the ignition point of about 500℃ is more than 6 times that of the methane component, but the heat released during the combustion process is only about 1 / 3 of that of methane. Therefore, the use of refinery gas as fuel not only causes the waste of high-value raw materials, but also causes a lot of energy waste. It is of great significance to classify and recover the components in refinery gas for high-value utilization to reduce costs and increase efficiency for enterprises.

[0003] In the process of separation and recovery of refinery gas, the traditional separation, purification and recovery processes mainly include compression condensation, pressure swing adsorption, membrane separation and coupling methods of several technologies. Due to the wide variety of refinery gases, the content of hydrogen and light hydrocarbon components varies greatly, and the recovery value of each component is greatly affected by market raw material price fluctuations. The traditional recovery process cannot meet the actual needs of effectively recovering a variety of refinery gases with different component contents. In addition, the light hydrocarbon and hydrogen recovery processes in the traditional coupling process are often embedded in each other's recovery process many times. The hydrogen recovery and light hydrocarbon recovery operations are complex and have a great influence on each other. It is impossible to flexibly adjust the recovery of hydrogen or light hydrocarbons separately according to the market value of the product. Therefore, in the process of separation and recovery of various refinery gases, it is urgently necessary to develop a process that can perform gradient recovery and utilization of various refinery gases and can flexibly adjust the recovery process according to the market value of the product. Summary of the invention

[0004] The purpose of the present invention is to propose a process and system for adjusting the gradient comprehensive recycling of multiple refinery gases in response to the many problems existing in the above-mentioned refinery gas recovery. The coupled processes of hydrogen and light hydrocarbon recovery of multiple refinery gases in this separation process and system are relatively independent, so that the hydrogen and light hydrocarbon recovery processes can promote each other and can be produced independently of each other, so that the recycling process can be flexibly adjusted with the fluctuation of product market prices. At the same time, according to the different hydrogen and light hydrocarbon compositions of the various refinery gases, they are classified so that the process has better adaptability to the fluctuation of refinery gas composition. The recovery process uses membrane separation technology and compression condensation technology to synchronously utilize the bidirectional enrichment gradient and the tail gas recycling of each logistics stream, which not only greatly improves the separation efficiency and recovery rate, but also reduces the separation energy consumption.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a comprehensive recovery and utilization process for adjusting multiple refinery gas gradients, comprising the following steps:

[0006] First, according to the different contents of hydrogen and light hydrocarbons, multiple refinery gases are divided into two categories: hydrogen-rich refinery gas and hydrogen-poor refinery gas. The high-concentration hydrogen-rich gas f-1, medium-concentration hydrogen-rich gas f-2, and low-concentration hydrogen-rich gas f-3 in the hydrogen-rich refinery gas are pressurized by the first compressor, the second compressor, and the third compressor respectively, and then enter the first pretreatment unit, the second pretreatment unit, and the third pretreatment unit respectively to remove liquid mist, dust and H2S impurities, and then adjust the temperature to 40-100°C before entering the high-concentration The gas f-4 treated by the first pretreatment unit is divided into two streams, gas f-5 and gas f-6, by the high-concentration hydrogen-rich membrane separation component. The gas f-5 is a hydrogen product gas with a hydrogen content of more than 90%, which can be used as a raw material for diesel hydrogenation or enter the hydrogen pipeline network (hydrogen-rich pipeline network). The light hydrocarbon-enriched gas f-6 is mixed with the gas f-7 treated by the second pretreatment unit and enters the medium-concentration hydrogen-rich membrane separation component. In the component, the medium-concentration hydrogen-rich membrane separation component is divided into two gas streams f-8 and gas f-9. Gas f-8 is a hydrogen product gas with a hydrogen content of more than 90%, which is mixed with gas f-5 as a process raw material for diesel hydrogenation or enters the hydrogen pipeline network (hydrogen-rich pipeline network). The light hydrocarbon secondary enriched gas f-9 enters the low-concentration hydrogen-rich membrane separation component; the low-concentration hydrogen-rich gas f-3 is pressurized by the third compressor and mixed with the tail gas f-10 after the light hydrocarbons are recovered by the first compression and condensation unit of the hydrogen-poor refinery gas to enter the third pretreatment The pretreated gas f-11 enters the low-concentration hydrogen-rich membrane separation component, and is divided into two streams, gas f-12 and gas f-13, by the low-concentration hydrogen-rich membrane separation component. Gas f-12 is a high-concentration hydrogen-rich gas with a hydrogen content of more than 60%, and is returned to the high-concentration hydrogen-rich membrane separation component or the medium-concentration hydrogen-rich membrane separation component for recycling; gas f-13 is a hydrocarbon-rich gas produced as a by-product of the hydrogen separation unit and can be used directly as fuel gas, or further separated from C2+ light hydrocarbons and methane to further recover light hydrocarbons.

[0007] Then, the hydrocarbon-rich gas f-13 produced as a by-product of the hydrogen separation unit enters the light hydrocarbon separation unit, and is divided into two gases f-14 and gas f-15 through the hydrocarbon-rich membrane separation component. Gas f-14 is methane-rich gas used as fuel gas, and gas f-15 is C2+-rich gas that is passed through the second compression and condensation unit to recover light hydrocarbons. The tail gas f-16 of the second compression and condensation unit is returned to the inlet of the hydrocarbon-rich membrane separation component for recycling.

[0008] Furthermore, the H2 concentration of the hydrogen-rich refinery gas is >20 vol%, and the H2 concentration of the hydrogen-depleted refinery gas is ≤20 vol%.

[0009] Furthermore, the H2 concentration of the high-concentration hydrogen-rich gas f-1 is 70 to 90 vol%, the H2 concentration of the medium-concentration hydrogen-rich gas f-2 is 40 to 70 vol%, and the H2 concentration of the low-concentration hydrogen-rich gas f-3 is 20 to 40 vol%.

[0010] Furthermore, the gas f-5 is a hydrogen product gas with a hydrogen content of more than 90%, which can be used as a raw material for processes such as diesel hydrogenation or enter a hydrogen pipeline network (hydrogen-rich pipeline network). Unless otherwise specified, % in this article refers to volume percentage.

[0011] Furthermore, the gas f-8 is a hydrogen product gas with a hydrogen content of more than 90%, which is mixed with the gas f-5 as a raw material for processes such as diesel hydrogenation or enters a hydrogen pipeline network (hydrogen-rich pipeline network).

[0012] Furthermore, the gas f-13 is a hydrocarbon-rich gas produced as a by-product of the hydrogen separation unit and can be used directly as fuel gas, or further separated from C2+ light hydrocarbons and methane to further recover light hydrocarbons.

[0013] Furthermore, the hydrogen-rich gas f-12 of the low-concentration hydrogen-rich membrane separation component can be returned to the first compressor inlet or the second compressor inlet for recycling as needed.

[0014] Another object of the present invention is to disclose a refinery gas purification, separation and recovery coupling system, a pretreatment unit, a compression and condensation unit, a hydrogen separation unit and a light hydrocarbon separation unit; the pretreatment unit includes a first pretreatment unit, a second pretreatment unit and a third pretreatment unit; the compression and condensation unit includes a first compression and condensation unit and a second compression and condensation unit; the hydrogen separation unit includes a high-concentration hydrogen-rich membrane separation component, a medium-concentration hydrogen-rich membrane separation component and a low-concentration hydrogen-rich membrane separation component; the light hydrocarbon separation unit includes a hydrocarbon-rich membrane separation component;

[0015] The inlet of the first pretreatment unit is connected to the high-concentration hydrogen-rich gas pipeline, the outlet of the first pretreatment unit is connected to the inlet of the high-concentration hydrogen-rich membrane separation component, the retentate side outlet of the high-concentration hydrogen-rich membrane separation component is connected to the inlet of the medium-concentration hydrogen-rich membrane separation component; the permeate side outlet of the high-concentration hydrogen-rich membrane separation component is connected to the hydrogen product gas pipeline;

[0016] The inlet of the second pretreatment unit is connected to the medium-concentration hydrogen-rich gas pipeline, the outlet of the second pretreatment unit is connected to the inlet of the medium-concentration hydrogen-rich membrane separation component, the retentate side outlet of the medium-concentration hydrogen-rich membrane separation component is connected to the inlet of the low-concentration hydrogen-rich membrane separation component, and the permeate side outlet of the medium-concentration hydrogen-rich membrane separation component is connected to the hydrogen product gas pipeline;

[0017] The inlet of the third pretreatment unit is connected to the low-concentration hydrogen-rich gas pipeline, the outlet of the third pretreatment unit is connected to the inlet of the low-concentration hydrogen-rich membrane separation component, the retentate side outlet of the low-concentration hydrogen-rich membrane separation component is connected to the inlet of the hydrocarbon-rich membrane separation component, and the permeate side of the low-concentration hydrogen-rich membrane separation component is connected to the high-concentration hydrogen-rich gas f-1 or the medium-concentration hydrogen-rich gas f-2 pipeline.

[0018] The inlet of the first compression and condensing unit is connected to the hydrogen-lean gas pipeline, the gas outlet of the first compression and condensing unit is connected to the inlet of the third pretreatment unit, the liquid outlet of the first compression and condensing unit is connected to the liquid hydrocarbon pipeline, the gas outlet of the second compression and condensing unit is connected to the inlet of the hydrocarbon-rich membrane separation component, the liquid outlet of the second compression and condensing unit is connected to the liquid hydrocarbon pipeline, the permeate side outlet of the hydrocarbon-rich membrane separation component is connected to the inlet of the second compression and condensing unit, and the retentate side outlet of the hydrocarbon-rich membrane separation component is connected to the fuel gas pipeline.

[0019] Furthermore, the refinery gas purification, separation and recovery coupling system also includes a compressor unit; the compressor unit includes a first compressor, a second compressor and a third compressor; the first compressor inlet is connected to a high-concentration hydrogen-rich gas pipeline, and the first compressor outlet is connected to a first pretreatment unit inlet; the second compressor inlet is connected to a medium-concentration hydrogen-rich gas pipeline, and the second compressor outlet is connected to a second pretreatment unit inlet; the third compressor inlet is connected to a low-concentration hydrogen-rich gas pipeline, and the third compressor outlet is connected to a third pretreatment unit inlet, and the low-concentration hydrogen-rich membrane separation component permeate side outlet is connected to the first compressor inlet or the second compressor inlet. Compressor units can be selectively added according to the refinery gas pressure.

[0020] Furthermore, the pretreatment unit includes a precision filter and a heat exchanger, the precision filter outlet is connected to the heat exchanger cold source inlet, and the heat exchanger cold source outlet is connected to the membrane separation component.

[0021] Furthermore, the pretreatment unit also includes a liquid separator (gas) and a demister, the gas outlet of the liquid separator is connected to the demister inlet, and the demister outlet is connected to the precision filter inlet.

[0022] Furthermore, the membrane separation component used in the hydrogen separation unit of the present invention is a hollow fiber membrane component, a flat membrane component, a tubular membrane component or a rolled membrane component.

[0023] The process and system for adjusting the gradient of various refinery gases for comprehensive recovery and utilization of the present invention have the following advantages compared with the prior art:

[0024] The present invention provides a process and system for adjusting the gradient comprehensive recycling of multiple refinery gases. By classifying and cascading the multiple refinery gases, the refinery gas recovery is more in line with the actual working conditions of the enterprise, and the process can be better adapted to the fluctuation of the content of refinery gas components, and the recovery rate of hydrogen and hydrogen hydrocarbons can be improved by recycling the tail gas. The process can realize the comprehensive recycling of refinery gas and simultaneously produce diversified products of hydrogen, liquid light hydrocarbons and fuel gas, with a hydrogen recovery rate of more than 90%, a hydrogen product purity of more than 90 vol%, a liquid hydrocarbon product C2+ content of more than 85 vol%, and a gas calorific value of not less than 31.4 MJ / Nm 3 National natural gas calorific value standard.

[0025] At the same time, by coupling the hydrogen separation unit and the light hydrocarbon separation unit in a relatively independent cascade, the hydrogen and light hydrocarbon recovery operations have little impact on each other, and some types of products can be selectively produced. In order to maintain the stability of the calorific value of the gas network, when the cost of recovering light hydrocarbons is higher than the cost of supplementing natural gas, the light hydrocarbon recovery unit can be shut down, and the by-product light hydrocarbon gas of the hydrogen separation unit can be directly supplied to the gas network. Conversely, the light hydrocarbon recovery unit can be opened to recover C2+ light hydrocarbons, and the high / medium / low concentration hydrogen separation membrane components can be flexibly entered according to the different gas compositions of the enterprise's refinery. This process can flexibly adjust the process recovery operation according to the fluctuations in market product value and product composition, so as to achieve flexible adjustment of economical production by enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Flow chart of comprehensive recovery and utilization process for adjusting various refinery gas gradients

[0027] in

[0028] 11 first compressor, 12 second compressor, 13 third compressor; 21 first pretreatment unit, 22 second pretreatment unit, 23 third pretreatment unit; 31 first compression condensation unit, 32 second compression condensation unit; S-1 hydrogen separation unit; S-2 light hydrocarbon separation unit; 41 high-concentration hydrogen-rich membrane separation component, 42 medium-concentration hydrogen-rich membrane separation component, 43 low-concentration hydrogen-rich membrane separation component; 51 hydrocarbon-rich membrane separation component. DETAILED DESCRIPTION

[0029] A process and system for adjusting the comprehensive recycling of multiple refinery gas gradients is implemented based on a refinery gas purification, separation and recycling coupling system. The refinery gas purification, separation and recycling coupling system is as follows: Figure 1 shown.

[0030] It includes a compressor unit, a pretreatment unit, a compression condensation unit, a hydrogen separation unit and a light hydrocarbon separation unit; the compressor unit includes a first compressor 11, a second compressor 12 and a third compressor 13; the pretreatment unit includes a first pretreatment unit 21, a second pretreatment unit 22 and a third pretreatment unit 23; the compression condensation unit includes a first compression condensation unit 31 and a second compression condensation unit 32; the hydrogen separation unit includes a high-concentration hydrogen-rich membrane separation component 41, a medium-concentration hydrogen-rich membrane separation component 42 and a low-concentration hydrogen-rich membrane separation component 43; the light hydrocarbon separation unit includes a hydrocarbon-rich membrane separation component 51;

[0031] The inlet of the first compressor 11 is communicated with the high-concentration hydrogen-rich gas pipeline, the outlet of the first compressor 11 is communicated with the inlet of the first pretreatment unit 21, the outlet of the first pretreatment unit 21 is communicated with the inlet of the high-concentration hydrogen-rich membrane separation component 41, the retentate side outlet of the high-concentration hydrogen-rich membrane separation component 41 is communicated with the inlet of the medium-concentration hydrogen-rich membrane separation component 42; the permeate side outlet of the high-concentration hydrogen-rich membrane separation component 41 is communicated with the hydrogen product gas pipeline;

[0032] The inlet of the second compressor 12 is communicated with the medium-concentration hydrogen-rich gas pipeline, the outlet of the second compressor 12 is communicated with the inlet of the second pretreatment unit 22, the outlet of the second pretreatment unit 22 is communicated with the inlet of the medium-concentration hydrogen-rich membrane separation component 42, the retentate side outlet of the medium-concentration hydrogen-rich membrane separation component 42 is communicated with the inlet of the low-concentration hydrogen-rich membrane separation component 43, and the permeate side outlet of the medium-concentration hydrogen-rich membrane separation component 42 is communicated with the hydrogen product gas pipeline;

[0033] The inlet of the third compressor 13 is communicated with the low-concentration hydrogen-rich gas pipeline, the outlet of the third compressor 13 is communicated with the inlet of the third pretreatment unit 23, the outlet of the third pretreatment unit 23 is communicated with the inlet of the low-concentration hydrogen-rich membrane separation component 43, the retentate side outlet of the low-concentration hydrogen-rich membrane separation component 43 is communicated with the inlet of the hydrocarbon-rich membrane separation component 51, and the permeate side outlet of the low-concentration hydrogen-rich membrane separation component 43 is communicated with the inlet of the first compressor 11;

[0034] The inlet of the first compression and condensing unit 31 is connected to the hydrogen-depleted gas pipeline, the gas outlet of the first compression and condensing unit 31 is connected to the inlet of the third pretreatment unit 23, the liquid outlet of the first compression and condensing unit 31 is connected to the liquid hydrocarbon pipeline, the gas outlet of the second compression and condensing unit 32 is connected to the inlet of the hydrocarbon-rich membrane separation component 51, the liquid outlet of the second compression and condensing unit 32 is connected to the liquid hydrocarbon pipeline, the permeate side outlet of the hydrocarbon-rich membrane separation component 51 is connected to the inlet of the second compression and condensing unit 32, and the retentate side outlet of the hydrocarbon-rich membrane separation component 51 is connected to the fuel gas pipeline.

[0035] The pretreatment unit includes a liquid separator, a demister, a precision filter and a heat exchanger. The gas outlet of the liquid separator is connected to the demister inlet, and the demister outlet is connected to the precision filter inlet. The precision filter outlet is connected to the heat exchanger cold source inlet, and the heat exchanger cold source outlet is connected to the membrane separation component.

[0036] The membrane separation component used in the hydrogen separation unit of the present invention is a hollow fiber membrane component, a flat membrane component, a tubular membrane component or a rolled membrane component.

[0037] The present invention regulates the comprehensive recovery and utilization process and system of multiple refinery gases, and performs classified gradient coupling separation and recovery according to the different contents of hydrogen and light hydrocarbons in each stream of refinery gas. The operation of the coupling process is relatively independent, so that the hydrogen and light hydrocarbon recovery processes can promote each other and can be produced independently of each other. Therefore, the recovery and utilization process can be flexibly adjusted with the fluctuation of product market price and raw material composition, which solves the problem that the hydrogen and light hydrocarbon recovery processes in the traditional separation process are repeatedly embedded in each other's process, resulting in complex hydrogen recovery and light hydrocarbon recovery operations and large mutual influence, and cannot be flexibly adjusted according to the volatility of product market value and raw material composition to recover hydrogen or light hydrocarbons separately. The process uses membrane separation technology and compression condensation technology to synchronously bidirectionally enrich the gradient utilization and tail gas recycling of each stream, which not only greatly improves the separation efficiency and recovery rate, but also reduces the separation energy consumption. The process can produce hydrogen products with a concentration of more than 90vol% required for direct diesel hydrogenation and other processes, liquid light hydrocarbons with a C2+ concentration greater than 85vol% and a calorific value not less than 31.4MJ / Nm 3 Standard gas.

[0038] The technical solution of the present invention is described below by means of specific embodiments:

[0039] Embodiment 1:

[0040] This embodiment discloses a process and system for adjusting the gradient of various refinery gases for comprehensive recycling and utilization. The refinery gases used are diesel reformed low-fraction gas, hydroisomerization dry gas, gas cabinet gas and reforming dry gas. The specific parameters are detailed in Table 1.

[0041] Table 1 List of key components and operating parameters of key materials (dry basis)

[0042]

[0043] Specifically, the process for adjusting the gradient of multiple refinery gases for comprehensive recycling and utilization is as shown in Question 1, and includes the following steps: First, multiple refinery gases are classified according to the different contents of hydrogen and light hydrocarbons, diesel reformed low-fraction gas is high-concentration hydrogen-rich gas f-1, hydrogen isomerization dry gas is medium-concentration hydrogen-rich gas f-2, gas cabinet gas is low-concentration hydrogen-rich gas f-3, and reformed dry gas is hydrogen-poor gas. After the high-concentration hydrogen-rich gas f-1 is pressurized to 2.2MPaG by the first compressor 11, liquid mist, dust and H2S impurities are removed by the first pretreatment unit 21, and the gas f-4 after the temperature is adjusted to 75°C enters the high-concentration hydrogen-rich membrane separation component 41, and a product gas f-5 with a H2 concentration of 98.63vol% is obtained on one side of the membrane 41, and a gas f-6 with a light hydrocarbon concentration of 22.03vol% and a hydrogen concentration of 66.98vol% is obtained on the other side.

[0044] The medium-concentration hydrogen-rich gas f-2 is pressurized to 2.1 MPaG by the second compressor 12, and passes through the second pretreatment unit 22 to remove liquid mist, dust and H2S impurities. The gas f-7 after the temperature is adjusted to 75°C and the light hydrocarbon-enriched gas f-6 are mixed and enter the medium-concentration hydrogen-rich membrane separation component 42. A product gas f-8 with a H2 concentration of 97.7% is obtained on one side of the membrane of the medium-concentration hydrogen-rich membrane separation component 42, and a gas f-9 with a light hydrocarbon concentration of 46.61 vol% and a hydrogen concentration of 36.45 vol% is obtained on the other side.

[0045] The low-concentration hydrogen-rich gas f-3 is pressurized to 2.0 MPaG by the third compressor 13 and mixed with the tail gas f-10 after the hydrogen-poor gas is compressed and condensed by the compression and condensation unit 31 for preliminary recovery of light hydrocarbons, and enters the third pretreatment unit 23 to remove liquid mist, dust and H2S impurities, and the gas f-11 after the temperature is adjusted to 75°C is mixed with the gas f-9 and enters the low-concentration hydrogen-rich membrane separation component 43. On one side of the membrane of the low-concentration hydrogen-rich membrane separation component 43, a gas f-12 with a H2 concentration of 84.93 vol% is obtained and circulated back to the inlet of the first compressor 11, and on the other side, a gas f-13 with a C2+ light hydrocarbon concentration of 49.78 vol% and a hydrogen concentration of 9.09 vol% is obtained. The hydrocarbon-rich gas produced as a by-product of the hydrogen separation unit can be directly used as fuel gas, or further separated from C2+ light hydrocarbons and methane to further recover light hydrocarbons.

[0046] Subsequently, the hydrocarbon-rich gas f-13 produced as a byproduct of the hydrogen separation unit enters the light hydrocarbon separation unit and is separated into two streams, gas f-14 and gas f-15, by the hydrocarbon-rich membrane separation component 51. Gas f-14 is a methane-rich gas with a methane content of 31.28 vol% and is used as fuel gas. The calorific value of the gas entering the gas network is 36.79 MJ / Nm 3The gas f-15 rich in C2+ with a content of 64.89 vol% passes through the second compression and condensation unit 32 for light hydrocarbon recovery, and the tail gas with a C2+ content of 41.49% of the second compression and condensation unit 32 is returned to the inlet of the hydrocarbon-rich membrane separation component 51 for recycling.

[0047] After being pressurized by the first compressor 11 and processed by the first pretreatment unit 21, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.2 MPaG.

[0048] After being pressurized by the second compressor 12 and processed by the second pretreatment unit 22, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.1 MPaG.

[0049] After being pressurized by the third compressor 13 and processed by the third pretreatment unit 23, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.0 MPaG.

[0050] The temperature of the first compression condensation unit 31 is 25°C, 2.0 MPaG.

[0051] The temperature of the second compression condensing unit 32 is 5°C, 2.0 MPaG.

[0052] In this implementation case, the main utility consumption includes: the power consumption of the first compressor 11, the second compressor unit 12, and the third compressor unit 13, the power consumption of the first compression condensing unit 31 and the second compression condensing unit 32, and the consumption of 5°C chilled water. The total installed power is 582Kw, and the total cooling load is 713MJ / h. The hydrogen product concentration is 98.11vol%, the hydrogen recovery rate is 92%, the liquid light hydrocarbon product C2+ concentration is greater than 96vol%, and the light hydrocarbon recovery rate is 83%. 6889Nm 3 / h natural gas to maintain the calorific value of the gas network unchanged, when the natural gas price is 2.0 yuan / Nm 3 When the value of liquid hydrocarbons is greater than RMB 3,827 / t, it will be economically beneficial to open the light hydrocarbon recovery unit S-2 to recover C2+ components.

[0053] Embodiment 2:

[0054] The refinery gas treated by the separation and recovery process provided by the present invention is hydrocracking low-fraction gas, PSA reforming analysis gas, PX isomerization dry gas, and hydrocoking dry gas. The specific parameters are shown in Table 1.

[0055] Table 1 List of key components and operating parameters of key materials (dry basis)

[0056]

[0057] The process for adjusting the gradient of various refinery gases for comprehensive recycling and utilization is as shown in Question 1, and includes the following steps: First, multiple streams of refinery gases are classified according to the different contents of hydrogen and light hydrocarbons, and the low-fraction gas from hydrocracking is a high-concentration hydrogen-rich gas f-1, the PSA reforming analysis gas is a medium-concentration hydrogen-rich gas f-2, the PX isomerization dry gas is a low-concentration hydrogen-rich gas f-3, and the hydrogenation coking dry gas is a hydrogen-poor gas. After the high-concentration hydrogen-rich gas f-1 is pressurized to 2.2MPaG by the first compressor 11, the liquid mist, dust and H2S impurities are removed by the first pretreatment unit 21, and the gas f-4 after the temperature is adjusted to 75°C enters the high-concentration hydrogen-rich membrane separation component 41, and a product gas f-5 with a H2 concentration of 98.66vol% is obtained on one side of the membrane of the high-concentration hydrogen-rich membrane separation component 41, and a gas f-6 with a light hydrocarbon concentration of 32.20vol% and a hydrogen concentration of 61.53vol% is obtained on the other side.

[0058] The medium-concentration hydrogen-rich gas f-2 is pressurized to 2.1 MPaG by the second compressor 12, and passes through the second pretreatment unit 22 to remove liquid mist, dust and H2S impurities. The gas f-7 after the temperature is adjusted to 75°C and the light hydrocarbon-enriched gas f-6 are mixed and enter the medium-concentration hydrogen-rich membrane separation component 42. A product gas f-8 with a H2 concentration of 94.51% is obtained on one side of the membrane 42, and a gas f-9 with a light hydrocarbon concentration of 60.61 vol% and a hydrogen concentration of 31.41 vol% is obtained on the other side.

[0059] The low-concentration hydrogen-rich gas f-3 is pressurized to 2.0 MPaG by the third compressor 13 and mixed with the tail gas f-10 after the hydrogen-poor gas is compressed and condensed by the compression and condensation unit 31 for preliminary recovery of light hydrocarbons, and enters the third pretreatment unit 23 to remove liquid mist, dust and H2S impurities, and the gas f-11 after the temperature is adjusted to 75°C is mixed with the gas f-9 and enters the low-concentration hydrogen-rich membrane separation component 43. On one side of the membrane of the low-concentration hydrogen-rich membrane separation component 43, a high-concentration hydrogen-rich gas f-12 with a H2 concentration of 83.37 vol% is obtained and circulated back to the inlet of the first compressor 11, and on the other side, a gas f-13 with a C2+ light hydrocarbon concentration of 48.69 vol% and a hydrogen concentration of 11.13 vol% is obtained. The hydrocarbon-rich gas as a by-product of the hydrogen separation unit can be directly used as fuel gas, or further separated from C2+ light hydrocarbons and methane to further recover light hydrocarbons.

[0060] Subsequently, the hydrocarbon-rich gas f-13 produced as a byproduct of the hydrogen separation unit enters the light hydrocarbon separation unit and is separated into two streams f-14 and f-15 by the hydrocarbon-rich membrane separation component 51. f-14 is a methane-rich gas with a methane content of 59.54 vol% and is used as fuel gas. The calorific value of the gas entering the gas network is 36.38 MJ / Nm 3f-15 The gas rich in C2+ with a content of 42.05 vol% passes through the second compression and condensation unit 32 for light hydrocarbon recovery, and the tail gas with a C2+ content of 34.89% of the second compression and condensation unit 32 is returned to the inlet of the hydrocarbon-rich membrane separation component 51 for recycling.

[0061] After being pressurized by the first compressor 11 and processed by the first pretreatment unit 21, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.2 MPaG.

[0062] After being pressurized by the second compressor 12 and processed by the second pretreatment unit 22, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.1 MPaG.

[0063] After being pressurized by the third compressor 13 and processed by the third pretreatment unit 23, the particle size of the particles and liquid mist entering the membrane separation unit is less than 0.01 um, the temperature is 75° C., and the pressure is 2.0 MPaG.

[0064] The temperature of the first compression condensation unit 31 is 25°C, 2.0 MPaG.

[0065] The temperature of the second compression condensing unit 32 is -25°C, 2.0 MPaG.

[0066] In this implementation case, the main utility consumption includes: the power consumption of the first compressor 11, the second compressor unit 12, and the third compressor unit 13, the power consumption of the compression condensation unit 31 and the compression condensation unit 32, and the -25°C ammonia refrigerant consumption, the total installed power is 967Kw, and the total cooling load is 1550MJ / h. The hydrogen product concentration is 96.65vol%, the hydrogen recovery rate is 92%, the liquid light hydrocarbon product C2+ concentration is greater than 94vol%, the light hydrocarbon recovery rate is 92%, and 14410Nm 3 / h natural gas to maintain the calorific value of the gas network unchanged, when the natural gas price is 2.0 yuan / Nm 3 When the value of liquid hydrocarbons is greater than RMB 3,725 / t, it will be economically beneficial to start the light hydrocarbon recovery unit S-2 to recover C2+ components.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive recycling process for adjusting the gradient of multiple refinery gases, characterized in that: The following steps are involved: First, according to the different contents of hydrogen and light hydrocarbons, multiple refinery gases are divided into two categories: hydrogen-rich refinery gases and hydrogen-poor refinery gases. The high-concentration hydrogen-rich gas f-1, the medium-concentration hydrogen-rich gas f-2, and the low-concentration hydrogen-rich gas f-3 in the hydrogen-rich refinery gases are pressurized by the first compressor (11), the second compressor (12), and the third compressor (13), respectively, and then enter the first pretreatment unit (21), the second pretreatment unit (22), and the third pretreatment unit (23) to remove liquid mist, dust and H2S impurities, and then adjust the temperature to 40-100° C. before entering the high-concentration hydrogen-rich membrane separation component (41), the medium-concentration hydrogen-rich membrane separation component (42), and the low-concentration hydrogen-rich membrane separation component (43); The gas f-4 treated by the first pretreatment unit (21) is separated into two gases by a high-concentration hydrogen-enriched membrane separation component (41), and the two gases are hydrogen product gas f-5 and light hydrocarbon primary enriched gas f-6; the light hydrocarbon primary enriched gas f-6 is mixed with the gas f-7 treated by the second pretreatment unit (22) and enters the medium-concentration hydrogen-enriched membrane separation component (42), and is separated into two gases by the medium-concentration hydrogen-enriched membrane separation component (42), and the two gases are hydrogen product gas f-8 and light hydrocarbon secondary enriched gas f-9; the light hydrocarbon secondary enriched gas f-9 enters the low-concentration hydrogen-enriched membrane separation component The low-concentration hydrogen-rich gas f-3 is pressurized by the third compressor (13) and mixed with the tail gas f-10 after light hydrocarbons are recovered by the first compression and condensation unit (31) of the hydrogen-depleted refinery gas, and enters the third pretreatment unit (23). The gas f-11 pretreated by the third pretreatment unit enters the low-concentration hydrogen-rich membrane separation component (43), and is separated into two gases by the low-concentration hydrogen-rich membrane separation component (43), the two gases being the hydrogen-rich gas f-12 and the hydrocarbon-rich gas f-13. The hydrogen-rich gas f-12 is returned and mixed with the high-concentration hydrogen-rich gas f-1 or the medium-concentration hydrogen-rich gas f-2 for recycling. Then, the hydrocarbon-rich gas f-13 produced as a by-product of the hydrogen separation unit enters the light hydrocarbon separation unit and is separated into two gases through the hydrocarbon-rich membrane separation component (51). The two gases are respectively methane-rich gas f-14 and C2+-rich gas f-15. The methane-rich gas f-14 is used as fuel gas, and the C2+-rich gas f-15 is recovered from light hydrocarbons through the second compression and condensation unit (32). The tail gas f-16 of the second compression and condensation unit (32) is returned to the inlet of the hydrocarbon-rich membrane separation component (51) for recycling.

2. The process for comprehensive recovery and utilization of multiple refinery gas gradients according to claim 1, characterized in that: The H2 concentration of the hydrogen-rich refinery gas is > 20 vol%, and the H2 concentration of the hydrogen-depleted refinery gas is ≤ 20 vol%.

3. The process for comprehensive recovery and utilization of multiple refinery gas gradients according to claim 1 or 2, characterized in that: The H2 concentration of the high-concentration hydrogen-rich gas f-1 is 70-90 vol%, the H2 concentration of the medium-concentration hydrogen-rich gas f-2 is 40-70 vol%, and the H2 concentration of the low-concentration hydrogen-rich gas f-3 is 20-40 vol%.

4. The process for comprehensive recovery and utilization of multiple refinery gas gradients according to claim 1, characterized in that: The hydrogen product gas f-5 is a hydrogen product gas with a hydrogen content of more than 90%, which can be used as a raw material for diesel hydrogenation process or enter the hydrogen pipeline network; the hydrogen product gas f-8 is a hydrogen product gas with a hydrogen content of more than 90%, which is mixed with the hydrogen product gas f-5 as a raw material for diesel hydrogenation process or enters the hydrogen pipeline network; the hydrocarbon-rich gas f-13 is a hydrocarbon-rich gas produced as a by-product of the hydrogen separation unit and can be directly used as fuel gas, or further separated from C2+ light hydrocarbons and methane to further recover light hydrocarbons.

5. The process for comprehensive recovery and utilization of multiple refinery gas gradients according to claim 1, characterized in that: The hydrogen-rich gas f-12 of the low-concentration hydrogen-rich membrane separation component can be returned to the first compressor inlet or the second compressor inlet for recycling as needed.

6. A refinery gas purification, separation and recovery coupling system, characterized in that: It comprises a pretreatment unit, a compression condensation unit, a hydrogen separation unit and a light hydrocarbon separation unit; the pretreatment unit comprises a first pretreatment unit (21), a second pretreatment unit (22) and a third pretreatment unit (23); the compression condensation unit comprises a first compression condensation unit (31) and a second compression condensation unit (32); the hydrogen separation unit comprises a high-concentration hydrogen-rich membrane separation component (41), a medium-concentration hydrogen-rich membrane separation component (42) and a low-concentration hydrogen-rich membrane separation component (43); the light hydrocarbon separation unit comprises a hydrocarbon-rich membrane separation component (51); The inlet of the first pretreatment unit (21) is connected to a high-concentration hydrogen-rich gas pipeline, the outlet of the first pretreatment unit (21) is connected to an inlet of a high-concentration hydrogen-rich membrane separation component (41), the retentate side outlet of the high-concentration hydrogen-rich membrane separation component (41) is connected to an inlet of a medium-concentration hydrogen-rich membrane separation component (42); the permeate side outlet of the high-concentration hydrogen-rich membrane separation component (41) is connected to a hydrogen product gas pipeline; The inlet of the second pretreatment unit (22) is connected to the medium-concentration hydrogen-rich gas pipeline, the outlet of the second pretreatment unit (22) is connected to the inlet of the medium-concentration hydrogen-rich membrane separation component (42), the retentate side outlet of the medium-concentration hydrogen-rich membrane separation component (42) is connected to the inlet of the low-concentration hydrogen-rich membrane separation component (43), and the permeate side outlet of the medium-concentration hydrogen-rich membrane separation component (42) is connected to the hydrogen product gas pipeline; The inlet of the third pretreatment unit (23) is connected to the low-concentration hydrogen-rich gas pipeline, the outlet of the third pretreatment unit (23) is connected to the inlet of the low-concentration hydrogen-rich membrane separation component (43), the retentate side outlet of the low-concentration hydrogen-rich membrane separation component (43) is connected to the inlet of the hydrocarbon-rich membrane separation component (51), and the permeate side outlet of the low-concentration hydrogen-rich membrane separation component (43) is connected to the high-concentration hydrogen-rich gas f-1 pipeline or the medium-concentration hydrogen-rich gas f-2 pipeline; The inlet of the first compression and condensing unit (31) is connected to the hydrogen-poor gas pipeline, the gas outlet of the first compression and condensing unit (31) is connected to the inlet of the third pretreatment unit (23), the liquid outlet of the first compression and condensing unit (31) is connected to the liquid hydrocarbon pipeline, the gas outlet of the second compression and condensing unit (32) is connected to the inlet of the hydrocarbon-rich membrane separation component (51), the liquid outlet of the second compression and condensing unit (32) is connected to the liquid hydrocarbon pipeline, the permeate side outlet of the hydrocarbon-rich membrane separation component (51) is connected to the inlet of the second compression and condensing unit (32), and the retentate side outlet of the hydrocarbon-rich membrane separation component (51) is connected to the fuel gas pipeline; The pretreatment unit comprises a precision filter and a heat exchanger, wherein the precision filter outlet is connected to the heat exchanger cold source inlet, and the heat exchanger cold source outlet is connected to the membrane separation component; The membrane separation component used in the hydrogen separation unit is a hollow fiber membrane component, a flat membrane component, a tubular membrane component or a rolled membrane component.

7. The refinery gas purification, separation and recovery coupling system according to claim 6, characterized in that: It comprises a compressor unit; the compressor unit comprises a first compressor (11), a second compressor (12), and a third compressor (13); The inlet of the first compressor (11) is connected to a high-concentration hydrogen-rich gas pipeline, and the outlet of the first compressor (11) is connected to an inlet of a first pretreatment unit (21); the inlet of the second compressor (12) is connected to a medium-concentration hydrogen-rich gas pipeline, and the outlet of the second compressor (12) is connected to an inlet of a second pretreatment unit (22); the inlet of the third compressor (13) is connected to a low-concentration hydrogen-rich gas pipeline, and the outlet of the third compressor (13) is connected to an inlet of a third pretreatment unit (23); and the permeate side outlet of the low-concentration hydrogen-rich membrane separation component (43) is connected to an inlet pipeline of the first compressor (11) or an inlet pipeline of the second compressor (12).

8. The refinery gas purification, separation and recovery coupling system according to claim 6, characterized in that: The pretreatment unit also includes a liquid separator and a demister, wherein the gas outlet of the liquid separator is connected to the inlet of the demister, and the outlet of the demister is connected to the inlet of the precision filter.

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