A method of absorption stabilization process

Abstract

The present disclosure relates to a method for absorption stabilization process, which comprises: sequentially treating an upstream product in a multi-stage cooling separation pressure increasing device to obtain a gas-rich phase and a condensed oil phase; treating the gas-rich phase, a supplementary absorbent and the liquid phase product under a pressure of 1.7-2.8 MPa (G) to obtain an absorption gas phase and an absorption oil phase; performing frozen separation on the absorption gas phase to obtain a hydrogen-rich dry gas and a condensed oil; mixing the condensed oil with the condensed oil phase and performing desorption treatment under a pressure of 0.6-1.5 MPa (G) to obtain a desorption gas and a desorption oil phase; returning the desorption gas to the multi-stage cooling separation pressure increasing device, and sequentially treating the desorption oil phase in a stabilization tower and a depropanizer to obtain a propane product, a C4-C5 component product and a C6+ component product. The present disclosure forms a differential pressure condition between the absorption treatment and the desorption treatment to perform the absorption stabilization process, which can reduce the energy consumption of the system while ensuring the quality of the products.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of petroleum chemical industry, in particular, to a method of absorption stabilization process. BACKGROUND

[0002] In recent years, with the increasing comprehensive utilization of petroleum chemical products and the pressure of energy saving and emission reduction of the device, optimizing the absorption stabilization process to improve the purity of C2 components in dry gas, increase the yield of liquefied gas and C3 components, and reduce the energy consumption of the system has become a widely and deeply researched direction. However, at present, most of the process devices containing absorption stabilization system are in operation, the pressures of the absorption tower and the desorption tower are related to each other and basically close to each other, most of them are double-tower processes, and the optimization work of the absorption stabilization process is also mostly carried out on this basis. The problem is that product upgrading and energy saving and consumption reduction are always mutually restricted, and it is difficult to achieve both. SUMMARY

[0003] The purpose of the present disclosure is to provide a method of absorption stabilization process to solve the problem that it is difficult to improve product quality while reducing system energy consumption in the prior art.

[0004] In order to achieve the above-mentioned purpose, the present disclosure provides a method of absorption stabilization process, which comprises: treating the upstream product after cooling separation and pressure increasing device to obtain gas phase product and liquid phase product; mixing the gas phase product, desorption gas and absorption oil phase to obtain pretreated material; wherein the pressure of the pretreated material is 1.9-3.0 MPa(G); the number of stages of the cooling separation and pressure increasing device is two or more than two; cooling the pretreated material to obtain rich gas phase and condensed oil phase after oil-gas separation; the liquid phase product and the supplementing absorbent are introduced into the absorption tower for absorption treatment to obtain absorption gas phase and the absorption oil phase; wherein the tower top pressure of the absorption treatment is 1.7-2.8 MPa(G); the absorption gas phase is subjected to refrigeration separation by a refrigeration separation device to obtain rich hydrogen dry gas and condensed oil; the rich hydrogen dry gas is treated by a purification unit to obtain hydrogen product and PSA desorption gas; the condensed oil is mixed with the condensed oil phase and then introduced into the desorption tower for desorption treatment to obtain the desorption gas and desorption oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa(G); the desorption oil phase is sequentially treated by a stabilizing tower and a depropanizer to obtain propane product, C4-C5 component product and C6+ component product.

[0005] Optionally, the cooling separation pressure boosting device has three stages; each stage of the cooling separation pressure boosting device comprises a cooler, a separation tank and a compressor; the outlet of the cooler is communicated with the inlet of the separation tank; the gas phase outlet of the separation tank is communicated with the inlet of the compressor, so that the material entering the cooling separation device is cooled by the cooler first, then enters the separation tank for gas-liquid separation, and the obtained gas phase is pressurized by the compressor.

[0006] Optionally, the method further comprises making the liquid phase product and the make-up absorbent enter from the upper part of the absorption tower and contact with the rich gas phase entering from the bottom of the absorption tower in countercurrent.

[0007] Optionally, the conditions of the absorption treatment comprise that the column bottom temperature is 12-60℃, the column top pressure is 2.0-2.7MPa(G), and the theoretical plate number of the absorption tower is 5-30; the conditions of the desorption treatment comprise that the column bottom temperature is 100-140℃, the column top pressure is 0.9-1.3MPa(G), and the theoretical plate number of the desorption tower is 5-35.

[0008] Optionally, the ratio of the operating pressure of the absorption tower to the operating pressure of the desorption tower is (1.1-3.1):1.

[0009] Optionally, the cooling source used by the refrigeration separation device is refrigerated water; the temperature of the refrigeration separation is 4-20℃.

[0010] Optionally, the gas phase product obtained by the cooling separation pressure boosting device is heated by a low-temperature hot water heat exchanger, then mixed with the absorption oil phase to obtain the pretreated material; the pretreated material is cooled by a feed cooling device.

[0011] Optionally, the method further comprises making the desorption oil phase enter a stabilizing tower for treatment to obtain a column top light component and a column bottom C6+ component; making the column bottom C6+ component at least into a first C6+ component and a second C6+ component; making the first C6+ component as the C6+ component product; making the second C6+ component as the make-up absorbent of the absorption tower; and making the column top light component enter the depropanizer for fractionation treatment to obtain the propane product and the C4-C5 component product.

[0012] Optionally, the desorption oil phase is heated by the column bottom C6+ component, then enters the stabilizing tower; the operating conditions of the stabilizing tower comprise that the column top pressure is 1.0-1.4MPa(G), the column top temperature is 35-45℃, and the column bottom temperature is 180-250℃; the operating conditions of the depropanizer comprise that the column top pressure is 1.2-1.6MPa(G), the column top temperature is 35-45℃, and the column bottom temperature is 90-97℃.

[0013] Optionally, the desorption tower is provided with a first reboiler in the middle part and a second reboiler at the bottom; the depropanizer is provided with a third reboiler at the bottom; the method further comprises using the C6+ components at the bottom of the tower and the desorption oil phase as heat sources of the first reboiler, the second reboiler and the third reboiler after heat exchange.

[0014] By the above technical solution, the present disclosure can improve the absorption performance of components above C3 by operating the absorption tower at a higher pressure, thereby reducing the amount of circulating absorbent and the energy consumption of the device; the desorption tower is operated at a lower pressure, which can improve the desorption performance of components below C2, thereby reducing the temperature during desorption treatment, and further reducing the system energy consumption. In addition, the upstream product is subjected to the absorption stabilization process under the differential pressure condition formed between the absorption treatment and the desorption treatment, which can ensure good separation effect, and further ensure the quality of the obtained product.

[0015] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments section. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and together with the following specific embodiments, serve to explain the present disclosure but do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 is a schematic diagram of a system of an absorption stabilization process according to the present disclosure.

[0018] Figure 2 is a schematic diagram of a system of an absorption stabilization process according to the present disclosure.

[0019] BRIEF DESCRIPTION OF DRAWINGS

[0020] 1 primary cooler; 2 primary knock-out drum; 3 primary compressor; 4 secondary cooler; 5 secondary knock-out drum; 6 secondary compressor; 7 tertiary cooler; 8 tertiary knock-out drum; 9 tertiary compressor; 10 low-temperature hot water heat exchanger; 11 feed cooler; 12 oil-gas separator; 13 absorption tower; 14 refrigeration separation device; 15 purification unit; 16 middle section cooler; 17 desorption tower; 18 first reboiler; 19 second reboiler; 20 stabilization tower; 21 stabilization tower overhead oil-gas condenser; 22 stabilization tower reflux drum; 23 stabilization tower reboiler; 24 make-up absorbent cooler; 25 depropanizer; 26 depropanizer overhead oil-gas condenser; 27 depropanizer reflux drum; 28 third reboiler; 29 hydrogen-rich dry gas compressor. DETAILED DESCRIPTION

[0021] The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended for explanation and interpretation of the present disclosure and are not intended to limit the present disclosure.

[0022] In the present disclosure, the orientation words such as "upper" and "lower" used herein generally refer to the upper and lower of the device in the normal use state, for example, with reference to the figure surface direction of Figure 1 , and "inner" and "outer" refer to relative to the outline of the device. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood or implied to indicate or imply relative importance or implicitly indicate the number of technical features indicated. Therefore, the features defined as "first", "second", "third" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0023] As shown in Figure 1 , the present disclosure provides a method for absorbing stable process, which comprises: treating the upstream product through a cooling separation pressure increasing device to obtain a gas phase product and a liquid phase product; mixing the gas phase product, a desorption gas and an absorption oil phase to obtain a pretreated material; wherein the pressure of the pretreated material is 1.9-3.0 MPa (G); the number of stages of the cooling separation pressure increasing device is two or more than two; cooling the pretreated material to obtain a rich gas phase and a condensed oil phase after oil-gas separation; introducing the rich gas phase, the liquid phase product and a supplementary absorbent into an absorption tower 13 for absorption treatment to obtain an absorption gas phase and the absorption oil phase; wherein the tower top pressure of the absorption treatment is 1.7-2.8 MPa (G); freezing and separating the absorption gas phase through a freezing separation device 14 to obtain a rich hydrogen dry gas and a condensed oil; treating the rich hydrogen dry gas through a purification unit 15, and sending the obtained purified hydrogen gas into a hydrogen pipeline network and the obtained PSA desorption gas out; mixing the condensed oil with the condensed oil phase and then introducing them into a desorption tower 17 for desorption treatment to obtain the desorption gas and a desorption oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa (G); treating the desorption oil phase through a stabilizing tower 20 and a depropanizing tower 25 in sequence to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0024] By the technical scheme, the absorption tower is operated at a higher pressure, the absorption performance of components above C3 is improved, the absorption agent recycling amount is reduced, and the energy consumption of the device is reduced. The desorption tower is operated at a lower pressure, the desorption performance of components below C2 is improved, the temperature during desorption treatment is reduced, and the system energy consumption is reduced. In addition, the upstream product is subjected to the absorption stabilization process under the differential pressure condition formed between the absorption treatment and the desorption treatment, the separation effect is good, and the quality of the obtained product is ensured.

[0025] In the present disclosure, the upstream product refers to one or more of the products of a light hydrocarbon conversion device, a catalytic cracking device, a delayed coking device, and a hydrocracking device.

[0026] In one embodiment, each stage of the cooling separation device in the present disclosure comprises a cooler, a liquid separation tank, and a compressor; the outlet of the cooler is in communication with the inlet of the liquid separation tank; the gas phase outlet of the liquid separation tank is in communication with the inlet of the compressor, so that the material entering the cooling separation device is first cooled by the cooler and then enters the liquid separation tank for gas-liquid separation, and the obtained gas phase is pressurized by the compressor. The liquid separation tank is a conventional selection in the art, and the present application does not have special requirements, as long as it can ensure that the device can separate gas and liquid, for example, the liquid separation tank in the present disclosure is a gas-liquid separation tower.

[0027] Preferably, the number of stages of the cooling separation device is 3, which are a first-stage cooling separation pressurizing device, a second-stage cooling separation pressurizing device, and a third-stage cooling separation pressurizing device.

[0028] In a specific embodiment, the upstream product is first subjected to preliminary cooling in a first-stage cooler 1, then subjected to separation in a first-stage liquid separation tank 2 to obtain a first gas phase and a first liquid phase and pressurize the first gas phase by a first-stage compressor 3; the pressurized first-stage gas phase is cooled by a second-stage cooler 4 and then sent to a second-stage liquid separation tank 5 for separation to obtain a second gas phase and a second liquid phase and pressurize the second gas phase by a second-stage compressor 6; the pressurized second-stage gas phase is mixed with the desorption gas, then cooled by a third-stage cooler 7, and then the cooled mixture is sent to a third-stage liquid separation tank 8 for separation to obtain a third gas phase and a third liquid phase and pressurize the third gas phase by a third-stage compressor 9 to 1.9-3.0 MPa(G) and then heat-exchanged by a low-temperature hot water heat exchanger 10; then the heat-exchanged mixture is mixed with the absorption oil to obtain a pretreated material, and the pretreated material is cooled to 12-60°C by a feed cooling device 11.

[0029] The desorption gas is returned to the first-stage cooling separation pressurizing device, the second-stage cooling separation pressurizing device, or the third-stage cooling separation pressurizing device.

[0030] In a preferred embodiment, the gaseous phase product obtained by the cooling separation pressure boosting device is mixed with the absorption oil phase after heat exchange by the low-temperature hot water heat exchanger 10 to obtain the pretreated material; and the pretreated material is cooled by the feed cooler 11.

[0031] In the above-mentioned embodiments, when the upstream product with a high temperature is separated, more components in the upstream product will be mixed in the gaseous phase under high-temperature conditions. Therefore, the gaseous phase product generated by the separation contains not only H2, components below C2 and C2 components, but also C3 components and components above C3. In order to improve the quality and yield of dry gas, the present disclosure increases the pressure of the gaseous phase product while reducing the temperature of the gaseous phase by the three-stage cooling separation device to improve the solubility of C3 components and components above C3 in the liquid phase product; and the temperature of the mixed gaseous phase is further reduced by the low-temperature hot water heat exchanger 10, thereby further improving the solubility of C3 components and components above C3 in the liquid phase product. In addition, since the absorption oil phase and the desorption gas are generated at a relatively low temperature, the temperature of the mixed feed is also relatively low, which can reduce the load of the feed cooler 11 and the energy consumption of the entire system.

[0032] In an embodiment, the pretreated material cooled by the feed cooler 11 enters the oil-gas separator 12 for oil-gas separation. In this embodiment, more C3 components and components above C3 are dissolved in the oil phase after the pretreated material is cooled, pressurized and separated by a series of temperature reduction and pressure increase, which can further ensure the quality of dry gas in the rich gas phase.

[0033] In an embodiment, the method further comprises: introducing the liquid phase product and the supplementary absorbent into the absorption tower 13 from the upper part of the absorption tower 13; introducing the rich gas phase separated by the oil-gas separator 12 into the absorption tower 13 from the bottom of the absorption tower 13; and realizing countercurrent contact between the liquid phase product, the supplementary absorbent and the rich gas phase under the action of gravity.

[0034] In order to strengthen the effect of countercurrent contact, a liquid phase product spraying device and a supplementary absorbent spraying device can be arranged at the upper part of the absorption tower 13, and a gas distributor can be arranged at the bottom of the absorption tower 13.

[0035] In the present disclosure, 1-4 middle-stage coolers 16 are arranged in the middle part of the absorption tower 13, preferably, two middle-stage coolers 16 are arranged at the 1 / 3 and 2 / 3 positions of the absorption tower 13, and the two middle-stage coolers 16 are arranged on the upper and lower floating trays.

[0036] In the present disclosure, a plurality of trays are arranged in the absorption tower 13 from top to bottom, and the number of trays in the absorption tower 13 is 5-30, preferably 8-20.

[0037] In this embodiment, the small amount of C3 components and components higher than C3 in the rich gas phase can be further reduced by countercurrent contact of the rich gas phase with the liquid phase product and the make-up absorbent, and the quality of the dry gas can be further improved. Furthermore, the effect of countercurrent contact can be further enhanced by selectively providing a sparger and a gas distributor in the absorption column 13, the stability of the temperature in the absorption column 13 can be ensured by providing the mid-stage cooler 16, and the absorption effect can be improved by prolonging the time of countercurrent contact between the gas phase and the liquid phase by providing a plurality of trays. In addition, by the above-mentioned arrangement, the absorption treatment can be maintained under the conditions of a column bottom temperature of 12-60°C, preferably 15-42°C, and a column top pressure of preferably 2.0-2.7 MPa (G), further preferably 2.1-2.6 MPa (G). In this embodiment, the absorption treatment is performed under the above-mentioned conditions, and the over-absorption in the absorption treatment can be avoided, and the energy consumption of the device can be reduced while ensuring the absorption treatment effect.

[0038] The purification unit 15 used in the present disclosure is conventionally selected in the art, and no special requirement is made in the present application. For example, the purification unit used in the present disclosure is a PSA unit. The purity of hydrogen obtained after the PSA unit treatment can reach 99v% or more, which can satisfy the use conditions of most hydrogen-using devices.

[0039] In one embodiment, the refrigeration separation device 14 used in the present disclosure includes a hydrogen-rich dry gas refrigerator and an aromatic recovery tank. When the hydrogen-rich dry gas enters the refrigeration separation device 14, the temperature is rapidly reduced by the hydrogen-rich dry gas refrigerator first, and the aromatics carried out by the hydrogen-rich dry gas are condensed at low temperature, and the condensed aromatics enter the aromatic recovery tank to obtain condensed oil. The temperature of the refrigeration separation is 4-20°C, preferably 6-12°C. In this embodiment, the cold source for the hydrogen-rich dry gas refrigerator can be a heat exchanger with chilled water as the cold source, or an ammonia or propane, propylene, ethylene refrigerator, preferably a heat exchanger with chilled water as the cold source.

[0040] In one embodiment, the desorption column 17 uses top cold feeding, and the feeding temperature is 10-60°C, preferably 35-45°C; a first reboiler 18 is provided in the middle part of the desorption column 17, and a second reboiler 19 is provided at the bottom. The load of the first reboiler 18 is 10%-50% of the load of the second reboiler 19, preferably 30%.

[0041] In one embodiment, the conditions of the desorption treatment include a column bottom temperature of 100-140°C, preferably 110-130°C; a column top pressure of preferably 0.9-1.3 MPa (G), further preferably 1.05-1.2 MPa (G); and a theoretical tray number of the desorption column 17 of 5-35.

[0042] Through the above-mentioned embodiments, the cold feed of the desorption tower 17 can make the mixed material gradually reduce the temperature during the process of running from the bottom to the top of the tower, so as to avoid the components from being entrained by the desorption gas, and further ensure the quality of the liquefied gas and the C6+ component product.

[0043] In an embodiment, the ratio of the operating pressure of the absorption tower 13 to the operating pressure of the desorption tower 17 is (1.1-3.1):1, preferably (1.8-2.8):1, and further preferably (2-2.6):1. In this embodiment, through the pressure difference generated between the absorption treatment and the desorption treatment, almost all of the C3 components and the components above C3 can be absorbed by the oil phase during the absorption treatment, so as to further improve the quality of the dry gas; and a small amount of components below C2 and C2 components absorbed in the oil phase are separated from the oil phase during the desorption treatment, so as to further improve the quality of the liquefied gas and the C6+ component product.

[0044] In an embodiment, the method further comprises: after the desorption oil phase is treated by the stabilizing tower 20, a stabilizing tower top light component and a tower bottom C6+ component are obtained; the tower bottom C6+ component is at least divided into a first C6+ component and a second C6+ component; the first C6+ component is discharged as the C6+ component product; the second C6+ component enters the absorption tower 13 as the supplementary absorbent; and the stabilizing tower top light component enters the depropanizer 25 for fractionation treatment, so as to obtain the propane product and the C4-C5 component product.

[0045] In the embodiment, a middle section cooler 16 is arranged on the pipeline through which the second C6+ component enters the absorption tower 13 as the supplementary absorbent, so as to ensure that the temperature of the supplementary absorbent is reduced to 4-20℃, and preferably 6-12℃.

[0046] In the embodiment, at least part of the tower bottom C6+ component is heated by a stabilizing tower reboiler 23 and then returned to the stabilizing tower 20 for treatment.

[0047] In the embodiment, the desorption oil phase exchanges heat with the C6+ component and then enters the stabilizing tower 20 for treatment.

[0048] In the embodiment, the C6+ component product, the tower bottom C6+ component, the first C6+ component and the second C6+ component mainly consist of C6-C9 components; and the tower top light component mainly consists of C3-C5 components.

[0049] In the embodiment, the operating conditions of the stabilizing tower 20 include: the tower top pressure is 1.0-1.4 MPa (G), the tower top temperature is 35-45℃, and the tower bottom temperature is 180-250℃.

[0050] The stable column top light component at the top of the stable column 20 is first cooled by the stable column top oil gas condenser 21 and then enters the stable column reflux tank 22 for reflux, and a part of the reflux product is circulated to the stable column 20, and another part of the reflux product enters the depropanizer 25.

[0051] The operating conditions of the depropanizer 25 include that the column top pressure is 1.2-1.6 MPa (G), the column top temperature is 35-45°C, and the column bottom temperature is 90-97°C.

[0052] The depropanizer bottom is provided with a third reboiler 28.

[0053] The method further includes that the column bottom C6+ component is heat exchanged with the desorption oil phase, and then is used as a heat source of the first reboiler 18, the second reboiler 19 and the third reboiler 28. In this embodiment, in order to further utilize the temperature of each section, the column bottom C6+ component is first heat exchanged with the desorption oil phase, and then is sequentially heat exchanged through the second reboiler 19, the third reboiler 28 and the first reboiler 18.

[0054] The depropanizer top material is cooled by the depropanizer top oil gas condenser 26 and then enters the depropanizer reflux tank 27 for reflux, and a part of the reflux product is circulated to the depropanizer 25, and another part of the reflux product is taken out of the system as a propane product.

[0055] The system used in the present disclosure further includes a low-temperature hot water system for recovering low-temperature heat in a petrochemical device. The recovered energy can be used for device equipment and pipeline heat tracing or power generation, etc.

[0056] In another embodiment, the depropanizer 25 of the present disclosure can be replaced by a debutanizer, and at this time, another part of the reflux product enters the debutanizer for treatment to obtain C3-C4 component products and C5 component products. In this embodiment, the depropanizer 25 and the debutanizer can be flexibly replaced according to the demand of products.

[0057] In one embodiment, as shown in FIG. 1, the method of the absorption stabilization process includes: Figure 1

[0058] ​After the upstream product is cooled initially in a first cooler 1 and separated in a first separator 2 to obtain a first gas phase and a first liquid phase and the first gas phase is pressurized by a first compressor 3, the pressurized first gas phase is cooled in a second cooler 4 and sent to a second separator 5 to obtain a second gas phase and a second liquid phase and the second gas phase is pressurized by a second compressor 6; the pressurized second gas phase is mixed with the desorption gas and sent to a third cooler 7 for cooling, and then the cooled mixture is sent to a third separator 8 to obtain a third gas phase and a third liquid phase and the third gas phase is pressurized by a third compressor 9 to 1.9-3.0 MPa (G) and then exchanged in a low-temperature hot water exchanger 10; then the exchanged mixture is mixed with the absorption oil to obtain a pretreated material, and the pretreated material is cooled to 12-60℃ by a feed cooler 11.

[0059] The pretreated material is separated into a gas-rich phase and a condensed oil phase in the feed cooler 11; the gas-rich phase, the supplemental absorbent and the liquid phase product are subjected to absorption treatment in an absorption tower 13 to obtain an absorption gas phase and an absorption oil phase; the absorption treatment conditions include a tower bottom temperature of 12-60℃, a tower top pressure of 1.7-2.8 MPa (G), and a theoretical plate number of the absorption tower of 5-30; the absorption gas phase is frozen to 4-20℃ by a refrigeration separation device 14 and then subjected to refrigeration separation to obtain a hydrogen-rich dry gas and a condensed oil; the hydrogen-rich dry gas is treated by a purification unit 15, and the obtained hydrogen product is sent to a hydrogen pipeline network; the condensed oil is mixed with the condensed oil phase and then subjected to desorption treatment in a desorption tower 17 to obtain a desorption gas and a desorption oil phase; the desorption treatment conditions include a tower bottom temperature of 100-140℃ and a tower top pressure of 0.6-1.5 MPa (G); the desorption gas is returned to the upstream of the first cooling separation pressurization device or the second cooling separation pressurization device or the third cooling separation pressurization device.

[0060] The desorbed oil phase is treated in the stabilizing tower 20 to obtain overhead light components and C6+ components at the bottom; the C6+ components at the bottom are heat-exchanged with the desorbed oil phase, and then heat-exchanged in sequence with the second reboiler 19, the third reboiler 28 and the first reboiler 18 to be divided into first C6+ components and second C6+ components; the first C6+ components are discharged as C6+ component products; the second C6+ components are fed into the absorption tower 13 as supplementary absorbents; the overhead light components of the stabilizing tower are fed into the depropanizer 25 for fractionation treatment to obtain the propane product, C4-C5 component product and C6+ component product; wherein the operating conditions of the stabilizing tower 20 include: the overhead pressure is 1.0-1.4 MPa (G), the overhead temperature is 35-45℃, and the bottom temperature is 180-250℃; the operating conditions of the depropanizer 25 include: the overhead pressure is 1.2-1.6 MPa (G), the overhead temperature is 35-45℃, and the bottom temperature is 90-97℃.

[0061] The method provided by the present application is further described below through specific examples, but the present application is not limited by the examples. The upstream products used in the examples are products of a certain 800,000 tons / year oil refining device, and the specific properties are shown in Table 1.

[0062] Table 1 Properties of upstream products

[0063] Items (mol%) Column total feed composition [H2] 69.00 [C1] 1.40 [C2] 1.50 [C3] 1.50 [C4] 1.40 [C5] 1.00 [C6] 4.60 [C7] 7.10 [C8] 7.00 C 9+ ]]> 5.50 Total 100

[0064] Example 1

[0065] The system of Figure 1 The method of absorption and stabilization process using the system comprises:

[0066] The upstream reaction product is cooled in the first cooler 1, separated in the first liquid separator 2 to obtain a first gas phase and a first liquid phase, and the first gas phase is pressurized by the first compressor 3; the pressurized first gas phase is cooled in the second cooler 4 and separated in the second liquid separator 5 to obtain a second gas phase and a second liquid phase, and the second gas phase is pressurized by the second compressor 6; the pressurized second gas phase is mixed with the desorption gas, cooled in the third cooler 7, and then the cooled mixture is separated in the third liquid separator 8 to obtain a third gas phase and a third liquid phase, and the third gas phase is pressurized to 2.6 MPa (G) by the third compressor 9 and heat-exchanged in the low-temperature hot water heat exchanger 10; then the heat-exchanged mixture is mixed with the absorption oil phase to obtain pretreated material, and the pretreated material is cooled to 40℃ by the feed cooler 11. The pretreated material is separated into a gas-rich phase and a condensed oil phase in the feed cooler 11;

[0067] The gas phase, the make-up absorbent and the liquid phase product are introduced into an absorption tower 13 for absorption treatment to obtain an absorption gas phase and an absorption oil phase; wherein the absorption treatment conditions include: a tower bottom temperature of 48°C, a pressure of 2.4 MPa (G), and a theoretical plate number of the absorption tower of 10; the absorption gas phase is cooled to 10°C by a refrigeration separation device 14 and then separated to obtain a hydrogen-rich dry gas and a condensed oil; the hydrogen-rich dry gas is treated by a PSA unit, and the obtained hydrogen product (with a purity of 99.9 mol%) is sent into a hydrogen pipeline network, and the obtained PSA desorption gas is discharged; the condensed oil is mixed with the condensed oil phase and then introduced into a desorption tower 17 for desorption treatment to obtain a desorption gas and a desorption oil phase; wherein the desorption treatment conditions include: a tower bottom temperature of 120°C, and a tower top pressure of 1.05 MPa (G);

[0068] The desorption oil phase is heated to 145°C by the tower bottom C6+ component of a stabilizing tower bottom, and then introduced into a stabilizing tower 20 for treatment to obtain a tower top light component and a tower bottom C6+ component; the tower bottom C6+ component of the stabilizing tower bottom is first heated by the desorption oil phase, and then sequentially heated by the second reboiler 19, the third reboiler 28 and the first reboiler 18 to be cooled to 40°C, and then divided into a first C6+ component and a second C6+ component; the first C6+ component is discharged as a C6+ component product; the second C6+ component is introduced into the absorption tower 13 as a make-up absorbent; the stabilizing tower top light component is introduced into a depropanizer 25 for fractionation treatment to obtain the propane product, the C4-C5 component product and the C6+ component product; wherein the operating conditions of the stabilizing tower 20 include: a pressure of 1.2 MPa (G), a tower top temperature of 40°C and a tower bottom temperature of 235°C; and the operating conditions of the depropanizer 25 include: a pressure of 1.4 MPa (G), a tower top temperature of 40°C and a tower bottom temperature of 93°C.

[0069] The product information and process parameters are shown in Table 2.

[0070] Comparative Example 1

[0071] The absorption and stabilization process is carried out by using a system as shown in Figure 2

[0072] The absorption and stabilization process is the same as that in Example 1, except that the operating pressure at the tower top of the absorption tower is 1.4 MPa (G), the operating pressure at the tower top of the desorption tower is 1.5 MPa (G), the three-stage cooling separation device (i.e. the three-stage cooler 7, the three-stage separation tank 8 and the three-stage compressor 9) is not provided, and the desorption gas at the tower top of the desorption tower is directly mixed with the reaction gas phase product and the saturated absorption oil at the tower bottom of the absorption tower to enter the compressed gas cooler. After the absorption gas at the tower top is separated after being cooled to 10°C by the refrigeration system, the obtained hydrogen-rich dry gas is pressurized to 2.35 MPa (G) by a hydrogen-rich dry gas compressor 29, sent to the PSA system to purify hydrogen, and then introduced into the hydrogen pipeline network.​

[0073] The product information and process parameters are shown in Table 2.

[0074] Table 2 Product properties and process parameters

[0075]

[0076] As shown in Table 1, according to the comparison of the data in Example 1 and Comparative Example 1 of the present disclosure, it can be seen that, by using the absorption stabilization process of the present disclosure, the content of C3 and above components in the hydrogen-rich dry gas in the example is reduced by 438 kg / h, and the content of C2, C1 and hydrogen components is increased by 35 kg / h. Not only can the absorption agent recycling amount be reduced, and the energy consumption of the device can be reduced, but also the temperature during desorption treatment can be reduced, thereby reducing the system energy consumption. In addition, by making the upstream product undergo the absorption stabilization process under the differential pressure condition formed between the absorption treatment and the desorption treatment, the separation effect can be ensured to be good, thereby ensuring the quality of the obtained product.

[0077] The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept range of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection range of the present disclosure.

[0078] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combination manners are not described again in the present disclosure.

[0079] In addition, various different embodiments of the present disclosure can also be combined in any manner, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. A method for an absorption stabilization process, characterized in that, The method includes: The upstream product is processed by a cooling separation and pressurization device to obtain a gaseous product and a liquid product; the gaseous product, desorbed gas and absorbed oil phase are mixed to obtain a pretreated material; wherein the pressure of the pretreated material is 1.9~3.0 MPa(G); the cooling separation and pressurization device has two or more stages; After the pretreated material is cooled down, oil and gas separation is performed to obtain a rich gas phase and a condensed oil phase; the rich gas phase, the liquid phase product and the supplementary absorbent are fed into the absorption tower (13) for absorption treatment to obtain the absorption gas phase and the absorption oil phase; wherein, the pressure at the top of the absorption tower is 1.7~2.8MPa(G); the absorption gas phase is subjected to refrigeration separation by the refrigeration separation device (14) to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is processed by the purification unit (15) to obtain hydrogen products and PSA desorption gas; The condensed oil and the condensed oil phase are mixed and then fed into a desorption tower (17) for desorption treatment to obtain the desorbed gas and the desorbed oil phase; wherein, the pressure at the top of the desorption tower is 0.6~1.5MPa(G); the desorbed oil phase is then processed sequentially through a stabilization tower (20) and a propane removal tower (25) to obtain propane product, C4~C5 component product and C6+ component product.

2. The method according to claim 1, characterized in that, The cooling separation and pressurization device has three stages; Each stage of the cooling separation and pressurization device includes a cooler, a separator, and a compressor; the outlet of the cooler is connected to the inlet of the separator; the gas phase outlet of the separator is connected to the inlet of the compressor, so that the material entering the cooling separation and pressurization device is first cooled by the cooler and then enters the separator for gas-liquid separation, and the resulting gas phase is pressurized by the compressor.

3. The method according to claim 1, characterized in that, The method further includes allowing the liquid phase product and the supplemental absorbent to enter from the top of the absorption tower (13) and to come into countercurrent contact with the rich gas phase entering from the bottom of the absorption tower (13).

4. The method according to claim 1, characterized in that, The absorption treatment conditions include: the bottom temperature of the tower is 12~60℃, the top pressure of the tower is 2.0~2.7MPa(G), and the theoretical number of plates of the absorption tower (13) is 5~30; The conditions for the desorption treatment include: the bottom temperature of the column is 100~140℃, the pressure at the top of the column is 0.9~1.3MPa(G), and the theoretical number of plates of the desorption column (17) is 5~35.

5. The method according to claim 1, characterized in that, The ratio of the operating pressure of the absorption tower (13) to that of the desorption tower (17) is (1.8~3.1):

1.

6. The method according to claim 1, characterized in that, The cold source used in the freezing separation device (14) is chilled water; the freezing separation temperature is 4~20℃.

7. The method according to claim 1, characterized in that, The method further includes mixing the gaseous product obtained from the cooling separation and pressurization device with the absorbent oil phase after heat exchange in a low-temperature hot water heat exchanger (10) to obtain the pretreated material; and cooling the pretreated material by a feed cooler (11).

8. The method according to claim 1, characterized in that, The method also includes treating the desorbed oil phase through a stabilizing tower (20) to obtain a light component at the top of the tower and a C6+ component at the bottom of the tower; The C6+ component at the bottom of the tower is divided into at least a first C6+ component and a second C6+ component; The first C6+ component is discharged as the C6+ component product. The second C6+ component is used as a supplementary absorbent for the absorption tower (13); The light component at the top of the column is fed into the propane removal column (25) for fractionation to obtain the propane product and the C4~C5 component product.

9. The method according to claim 8, characterized in that, After heat exchange with the C6+ component at the bottom of the tower, the desorbed oil phase enters the stabilizer (20). The operating conditions of the stabilizer tower (20) include: a tower top pressure of 1.0~1.4MPa(G), a tower top temperature of 35~45℃, and a tower bottom temperature of 180~250℃; The operating conditions of the propane removal tower (25) include: a top pressure of 1.2~1.6 MPa(G), a top temperature of 35~45℃, and a bottom temperature of 90~97℃.

10. The method according to claim 8, characterized in that, The desorption tower (17) is provided with a first reboiler (18) in the middle and a second reboiler (19) at the bottom; the propane removal tower is provided with a third reboiler (28) at the bottom. The method further includes exchanging heat between the bottom C6+ component and the desorbed oil phase, and using it as a heat source for the first reboiler (18), the second reboiler (19) and the third reboiler (28).

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