A method of absorption stabilization process

Abstract

The present disclosure relates to a method for absorption stabilization process, which comprises: cooling, pressurizing and separating an upstream product to obtain a gas-rich phase and a condensed oil phase; subjecting the gas-rich phase, a supplementary absorbent and the liquid phase product to absorption treatment under a pressure of 1.7-2.8 MPa (G) to obtain an absorption gas phase and an absorption oil phase; subjecting the absorption gas phase to refrigeration separation to obtain a hydrogen-rich dry gas and a condensed oil; mixing the condensed oil with the condensed oil phase and subjecting the mixture to desorption treatment under a pressure of 0.6-1.5 MPa (G) to obtain a desorption gas and a desorption oil phase; and subjecting the desorption oil phase to treatment by a stabilizing tower and a depropanizing tower in sequence 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 carry out 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] Absorption stabilization process is a product separation unit of light hydrocarbon conversion, catalytic cracking, delayed coking and hydrocracking device in the field of petroleum processing, which mainly consists of absorption tower, desorption tower and stabilization tower, and corresponding heat exchange equipment and auxiliary equipment such as pumps, and its main purpose is to separate rich gas and crude gasoline into dry gas (H2, C2 and C2 below), liquefied gas and gasoline whose vapor pressure meets product specifications by using absorption and rectification method.

[0003] In recent years, with the increasing pressure of comprehensive utilization of petroleum chemical products and energy saving and emission reduction of the device in China, it has become a widely and in-depth research direction to continuously optimize the process of absorption stabilization system, refine the operating conditions and propose technical improvement measures to improve the purity of dry gas C2 and below, increase the yield of liquefied gas and C3 components and reduce the energy consumption of the system, and some effects have been achieved.

[0004] At present, most of the process devices containing absorption stabilization system are running, the pressures of absorption tower and desorption tower are related to each other and basically close to each other, most of them are double tower process, and the optimization work of absorption stabilization process is also mostly carried out on this basis, and the problem is that product upgrading and energy saving and consumption reduction are always restricted to each other, and it is difficult to achieve both. SUMMARY

[0005] 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.

[0006] To achieve the above object, the present disclosure provides a method for absorption stabilization process, which comprises: cooling an upstream product and performing a first separation to obtain a gas phase product and a liquid phase product; compressing and cooling the gas phase product and performing a second separation to obtain a rich gas phase and a condensed oil phase; feeding the rich gas phase, a supplementary absorbent and the liquid phase product into an absorption tower for absorption treatment to obtain an absorption gas phase and an 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 by a freezing separation device to obtain a hydrogen-rich dry gas and a condensed oil; treating the hydrogen-rich dry gas by a purification unit to obtain a hydrogen product and a PSA desorption gas; mixing the condensed oil with the condensed oil phase and feeding the mixture into a desorption tower for desorption treatment to obtain a desorption gas and a desorption oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa(G); pressurizing the desorption gas to 1.7-2.8 MPa(G) and mixing the pressurized desorption gas with the gas phase product and the absorption oil phase for the second separation; treating the desorption oil phase by a stabilizing tower and a depropanizing tower in sequence to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0007] Optionally, the method further comprises feeding the liquid phase product and the supplementary absorbent into the upper part of the absorption tower and countercurrently contacting the rich gas phase fed into the bottom part of the absorption tower.

[0008] Optionally, the conditions of the absorption treatment comprise: a tower bottom temperature of 12-60℃, a tower top pressure of 2.0-2.7 MPa(G), and a theoretical plate number of the absorption tower of 5-30; and the conditions of the desorption treatment comprise: a tower bottom temperature of 100-140℃, a tower top pressure of 0.9-1.3 MPa(G), and a theoretical plate number of the desorption tower of 5-35.

[0009] Optionally, the ratio of the operating pressures of the absorption tower and the desorption tower is (1.1-3.1):1.

[0010] Optionally, the cold source used by the freezing separation device is chilled water; and the temperature of the freezing separation is 4-20℃.

[0011] Optionally, before the second separation, the gas phase obtained by sequentially treating the gas phase product by a rich gas compressor and a low-temperature hot water heat exchanger is mixed with the absorption oil phase and the pressurized desorption gas to obtain a mixed feed; and the mixed feed is cooled by a cooler.

[0012] Optionally, the method further comprises, after the desorption oil phase is treated by the stabilizing tower, obtaining a stabilizing tower top light component and a tower bottom C6+ component; 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 is introduced into the absorption tower as the supplementary absorbent; and the stabilizing tower top light component is introduced into the depropanizer for fractionation treatment, to obtain the propane product and the C4-C5 component product.

[0013] Optionally, after the desorption oil phase exchanges heat with the tower bottom C6+ component, the desorption oil phase enters the stabilizing tower.

[0014] Optionally, the operating conditions of the stabilizing tower include that 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 ℃; and the operating conditions of the depropanizer include that the tower top pressure is 1.2-1.6 MPa (G), the tower top temperature is 35-45 ℃, and the tower bottom temperature is 90-97 ℃.

[0015] Optionally, a first reboiler is arranged in the middle of the desorption tower, and a second reboiler is arranged at the bottom of the desorption tower; a third reboiler is arranged at the bottom of the depropanizer; and the method further comprises using the tower bottom C6+ component as the heat source of the first reboiler, the second reboiler, and the third reboiler.

[0016] By the above technical solution, the absorption tower is operated at a higher pressure, which can improve the absorption performance of the C3+ component, thereby reducing the amount of absorbent in circulation and reducing the energy consumption of the device; the desorption tower is operated at a lower pressure, which can improve the desorption performance of the C2+ component, thereby reducing the temperature during desorption treatment and further reducing the energy consumption of the system. In addition, the upstream product is subjected to the absorption and stabilization process under the differential pressure condition formed between the absorption treatment and the desorption treatment, which can ensure good separation effect, thereby ensuring the quality of the obtained product.

[0017] Other features and advantages of the present disclosure will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0019] Figure 1 is a schematic diagram of a system of an absorption and stabilization process according to the present disclosure.

[0020] Figure 2 is a schematic diagram of a system of an absorption and stabilization process according to the comparative example of the present disclosure.

[0021] Reference Signs List

[0022] 1 reaction product cooler; 2 reaction product separator; 3 rich gas compressor; 4 low temperature hot water heat exchanger; 5 feed cooler; 6 oil gas separator; 7 absorption column; 8 refrigeration separation device; 9 purification unit; 10 mid-stage cooler; 11 desorption column; 12 desorption gas booster; 13 first reboiler; 14 second reboiler; 15 stabilizer column; 16 stabilizer overhead oil gas condenser; 17 stabilizer reflux drum; 18 stabilizer column reboiler; 19 make-up absorbent cooler; 20 depropanizer; 21 depropanizer overhead oil gas condenser; 22 depropanizer reflux drum; 23 third reboiler; 24 hydrogen-rich dry gas compressor. DETAILED DESCRIPTION

[0023] The specific embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0024] In the present disclosure, the orientation words such as "upper" and "lower" are generally used to refer to the upper and lower of the device in the normal use state, for example, referring to the figure surface direction of Figure 1 , and "inner" and "outer" refer to relative to the device profile. In addition, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0025] As Figure 1As shown, the present disclosure provides a method for absorption stabilization process, which comprises: cooling the upstream product and then performing first separation to obtain a gas phase product and a liquid phase product; compressing and cooling the gas phase product and then performing second separation to obtain a rich gas phase and a condensed oil phase; introducing the rich gas phase, a supplementary absorbent and the liquid phase product into an absorption tower 7 for absorption treatment to obtain an absorption gas phase and an absorption oil phase; wherein the tower top pressure of the absorption treatment is 1.7-2.8 MPa(G); introducing the absorption gas phase into a refrigeration separation device 8 for refrigeration separation to obtain a hydrogen-rich dry gas and a condensed oil; introducing the hydrogen-rich dry gas into a PSA unit 9 for treatment, and then sending the obtained purified hydrogen into a hydrogen pipeline network and the obtained PSA desorption gas out; mixing the condensed oil with the condensed oil phase and then introducing the mixture into a desorption tower 11 for desorption treatment to obtain a desorption gas and a desorption oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa(G); mixing the desorption gas, which is pressurized to 1.7-2.8 MPa(G), with the gas phase product and the absorption oil phase for the second separation; and introducing the desorption oil phase into a stabilizing tower 15 and a depropanizing tower 20 in sequence for treatment to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0026] Through the above technical solution, the present disclosure can improve the absorption performance of components above C3 by operating the absorption tank at a higher pressure, thereby reducing the amount of absorbent in circulation 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, so as to reduce the temperature during desorption treatment, thereby reducing the energy consumption of the system. 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, thereby ensuring the quality of the obtained product.

[0027] 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.

[0028] In one embodiment, the present disclosure first cools the upstream product in a reaction product cooler 1 and then introduces it into a reaction product separator 2 for first separation. The reaction product cooler 1 and the reaction product separator 2 are conventional choices in the art, and the present application does not make special requirements, as long as the device can cool the upstream product and the device can separate gas and liquid.

[0029] In one embodiment, the obtained gas phase product is pressurized to 1.9-3.0 MPa(G) by a rich gas compressor 3, and then sent into a low-temperature hot water heat exchanger 4 for heat exchange, so that the temperature of the gas phase product is reduced to 75-95℃. The low-temperature hot water heat exchanger 4 uses the gas phase product as a heat source and water as a cold source.

[0030] In one embodiment, the gas phase exchanged by the low-temperature hot water exchanger 4 is mixed with the absorption oil phase and the desorbed gas pressurized by the desorbed gas booster 12 to obtain a mixed feed; and the mixed feed is further cooled to 12-50℃ by the feed cooler 5.

[0031] In the above embodiment, when the first separation is performed on the upstream product with a high temperature, more components in the upstream product will be mixed in the gas phase under high-temperature conditions. Therefore, the gas 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 disclosure increases the pressure in the gas phase product by the rich gas compressor 3 to improve the solubility of C3 components and components above C3 in the liquid phase product; and the temperature of the gas phase product is reduced by the low-temperature hot water exchanger 4, 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 desorbed 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 mixed feed on the feed cooler 5 and reduce the energy consumption of the entire system.

[0032] In one embodiment, the mixed feed cooled by the feed cooler 5 enters the oil-gas separator 6 for the second separation. In this embodiment, the mixed feed after a series of temperature reduction and pressure increase is subjected to the second separation, and more C3 components and components above C3 are dissolved in the oil phase, which can further ensure the quality of the dry gas in the rich gas phase.

[0033] In one embodiment, the method further comprises: introducing the liquid phase product separated by the reaction product separator 2 and the supplemental absorbent into the absorption tower 7 from the upper part of the absorption tower 7; introducing the rich gas phase separated by the oil-gas separator 6 into the absorption tower 7 from the bottom of the absorption tower 7; and realizing countercurrent contact between the liquid phase product, the supplemental 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 supplemental absorbent spraying device can be arranged at the upper part of the absorption tower 7, and a gas distributor can be arranged at the bottom of the absorption tower 7.

[0035] In the present disclosure, 1-4 middle section coolers 10 are arranged in the middle part of the absorption tower 7, preferably 2 middle section coolers 10 are arranged at 1 / 3 and 2 / 3 of the absorption tower 1, respectively, and the two middle section coolers 10 are arranged on the upper and lower floating tower plates.

[0036] In the present disclosure, a plurality of tower plates are arranged in the absorption tower 7 from top to bottom, and the number of tower plates in the absorption tower 7 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 7, the stability of the temperature in the absorption column 7 can be ensured by providing the mid-column cooler 10, and the residence time of countercurrent contact between the gas phase and the liquid phase can be prolonged and the absorption effect can be improved 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 effect of the absorption treatment.

[0038] The purification unit 9 used in the present disclosure is a conventional selection 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 treatment by the PSA unit can reach 99v% or more, which can satisfy the use conditions of most hydrogen-using devices.

[0039] In one embodiment, the refrigeration separation device 8 used in the present disclosure includes a hydrogen-rich dry gas refrigerator and an aromatic hydrocarbon recovery tank. When the hydrogen-rich dry gas enters the refrigeration separation device 8, the temperature is rapidly reduced by the hydrogen-rich dry gas refrigerator first, and the aromatic hydrocarbons carried out by the hydrogen-rich dry gas are condensed at low temperature, and the condensed aromatic hydrocarbons enter the aromatic hydrocarbon 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 11 uses top cold feeding, and the feeding temperature is 10-60°C, preferably 35-45°C; a first reboiler 13 is provided in the middle part of the desorption column 11, and a second reboiler 14 is provided at the bottom. The load of the first reboiler 13 is 10%-50% of the load of the second reboiler 14, 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 11 of 5-35.

[0042] Through the above embodiments, the cold feed of the desorption tower 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 7 to the operating pressure of the desorption tower 11 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 15, 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 7 as the supplementary absorbent; and the stabilizing tower top light component enters the depropanizer 20 for fractionation treatment, so as to obtain the propane product and the C4-C5 component product.

[0045] In the embodiment, at least part of the tower bottom C6+ component is heated by a stabilizing tower reboiler 18 and then returned to the stabilizing tower 15, so as to maintain the stability of the temperature of the stabilizing tower.

[0046] In the embodiment, the desorption oil phase exchanges heat with the tower bottom C6+ component and then enters the stabilizing tower 15 for treatment.

[0047] 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.

[0048] In the embodiment, the operating conditions of the stabilizing tower 15 include: the tower top pressure is 1.0-1.4 MPa (G), the tower top temperature is 35-45°C, and the tower bottom temperature is 180-250°C.

[0049] In the embodiment, the stabilizing tower top light component at the top of the stabilizing tower 15 is first cooled by a stabilizing tower top oil gas condenser 16 and then enters a stabilizing tower reflux tank 17 for reflux, part of the reflux product is circulated to the stabilizing tower 15, and the other part of the reflux product enters the depropanizer 20.

[0050] The operating conditions of the propane removal column 20 include: a column top pressure of 1.2–1.6 MPa(G), a column top temperature of 35–45°C, and a column bottom temperature of 90–97°C.

[0051] The bottom of the propane removal tower is equipped with a third reboiler 23.

[0052] The method further includes using the bottom C6+ component as a heat source for the first reboiler 13, the second reboiler 14, and the third reboiler 23, so that the bottom C6+ component can exchange heat with the interrupted material in the absorber, the bottom material in the absorber, and the bottom material in the propane removal tower. In this embodiment, to further utilize the temperature of each stage, the bottom C6+ component can first exchange heat with the desorbed oil phase, and then sequentially pass through the second reboiler 14, the third reboiler 23, and the first reboiler 13 for heat exchange.

[0053] In this process, the material from the top of the propane dehydrogenator is cooled by the oil-gas condenser 21 and then refluxed into the reflux tank 22. A portion of the reflux product is recycled back to the propane dehydrogenator 20, while the other portion of the reflux product exits the system as propane.

[0054] The system used in this disclosure also includes a cryogenic hot water system for recovering cryogenic heat from petrochemical plants. The recovered energy can be used for heat tracing of equipment and pipelines or for power generation.

[0055] In another embodiment, the propane remover 20 of this disclosure can be replaced with a butane remover. In this case, another portion of the reflux product is fed into the butane remover for processing to obtain C3-C4 and C5 component products. In this embodiment, the propane remover 20 and the butane remover can be flexibly replaced according to product requirements.

[0056] In one implementation, such as Figure 1 As shown, the absorption stabilization process includes the following methods:

[0057] After initial cooling in the reaction product cooler 1, the upstream product enters the reaction product separator 2 for the first separation, yielding a gaseous product and a liquid product. The obtained gaseous product is then pressurized to 1.9–3.0 MPa(G) by the rich gas compressor 3 and fed into the low-temperature hot water heat exchanger 4 for heat exchange, reducing the temperature of the gaseous product to 75–95°C. The low-temperature hot water heat exchanger 4 uses the gaseous product as the heat source and water as the cold source. The gaseous product heated by the low-temperature hot water heat exchanger 4 is mixed with the absorbed oil phase and the pressurized desorbed gas to obtain a mixed feed. The mixed feed is further cooled to 12–60°C by the feed cooler 5 and then undergoes a second separation, yielding a rich gas phase and a condensed oil phase.

[0058] The gas phase, the make-up absorbent and the liquid phase product are introduced into an absorption tower 7 for absorption treatment to obtain an absorption gas phase and an absorption oil phase; wherein the absorption treatment conditions include: the column bottom temperature is 12-60℃, the column top pressure is 1.7-2.8 MPa (G), and the theoretical plate number of the absorption tower is 5-30; the absorption gas phase is frozen to 4-20℃ by a freezing separation device 8 and then subjected to freezing separation to obtain a hydrogen-rich dry gas and a condensed oil; the hydrogen-rich dry gas is subjected to treatment by a purification unit 9, and the obtained hydrogen product 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 11 for desorption treatment to obtain a desorption gas and a desorption oil phase; wherein the desorption treatment conditions include: the column bottom temperature is 100-140℃, and the column top pressure is 0.6-1.5 MPa (G); the desorption gas is pressurized to 1.7-2.8 MPa (G) by a desorption gas booster 12 and then mixed with the gas phase product and the absorption oil phase for the second separation.

[0059] The desorption oil phase is subjected to treatment by a stabilizing tower 15 to obtain a stabilizing tower top light component and a column bottom C6+ component; the column bottom C6+ component is first heat-exchanged with the desorption oil phase and then heat-exchanged in sequence by a second reboiler 14, a third reboiler 23 and a first reboiler 13 to be 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 7 as a make-up absorbent; the stabilizing tower top light component is introduced into a depropanizer 20 for fractionation treatment to obtain the propane product and the C4-C5 component product; wherein the operating conditions of the stabilizing tower 15 include: the column top pressure is 1.0-1.4 MPa (G), the column top temperature is 35-45℃, and the column bottom temperature is 180-250℃; the operating conditions of the depropanizer 20 include: the column top pressure is 1.2-1.6 MPa (G), the column top temperature is 35-45℃, and the column bottom temperature is 90-97℃.

[0060] The method provided by the present application is further described below by specific examples, but the present application is not limited by the examples. The upstream product used in the examples is the product of a certain 800,000 tons / year oil refining device, and the specific properties are shown in Table 1.

[0061] Table 1 Properties of upstream product

[0062] Items (mol%) Column total feed composition [H2] 69.00 [C2] 1.40 1.40 [C2] 1.50 [C3] 1.50 [C4] 1.40 [C5] 1.00 [C6] 4.60 [C7] 7.10 [C8] 7.00 [00000C1] 9+ ]]> 5.50 Total 100

[0063] Example 1

[0064] The method for absorption and stabilization process by using the system of Figure 1 includes:

[0065] After the upstream product is preliminarily cooled in a reaction product cooler 1, it is subjected to a first separation in a reaction product separator 2 to obtain a gas phase product and a liquid phase product; the obtained gas phase product is pressurized to 2.6 MPa (G) by a gas enrichment compressor 3, and then is subjected to heat exchange in a low-temperature hot water heat exchanger 4 to reduce the temperature of the gas phase product to 83℃. In the low-temperature hot water heat exchanger 4, the gas phase product is used as a heat source and water is used as a cold source. The gas phase product subjected to heat exchange in the low-temperature hot water heat exchanger 4 is mixed with the absorption oil phase and the pressurized desorption gas to obtain a mixed feed; the mixed feed is further cooled to 40℃ by a feed cooler 5, and then is subjected to a second separation to obtain a gas enrichment phase and a condensed oil phase;

[0066] The gas enrichment phase, the supplementary absorption agent and the liquid phase product are subjected to absorption treatment in an absorption tower 7 to obtain an absorption gas phase and an absorption oil phase; the absorption treatment is carried out under the conditions of a tower bottom temperature of 48℃, a tower top pressure of 2.4 MPa (G) and a theoretical plate number of the absorption tower of 10. The absorption gas phase is subjected to separation after being frozen to 10℃ by a refrigeration separation device 8 to obtain a hydrogen-rich dry gas and a condensed oil. The hydrogen-rich dry gas is subjected to treatment by a purification unit 9, and the obtained hydrogen product (with a purity of 99.9 mol%) is sent to a hydrogen pipeline network, and the obtained PSA desorption gas is discharged. The condensed oil is mixed with the condensed oil phase, and then is subjected to desorption treatment in a desorption tower 11 to obtain a desorption gas and a desorption oil phase; the desorption treatment is carried out under the conditions of a tower bottom temperature of 120℃ and a tower top pressure of 1.05 MPa (G). The desorption gas is pressurized to 2.5 MPa (G) by a desorption gas pressurizing machine 12, and then is mixed with the gas phase product and the absorption oil phase to carry out the second separation;

[0067] The desorption oil phase is subjected to heat exchange with the tower bottom C6+ component of a stabilizing tower to 145℃, and then is subjected to treatment in the stabilizing tower 15 to obtain a stabilizing tower top light component and a tower bottom C6+ component. The tower bottom C6+ component is first subjected to heat exchange with the desorption oil phase, and then is subjected to heat exchange and temperature reduction to 40℃ in sequence by a second reboiler 14, a third reboiler 23 and a first reboiler 13 to be 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 used as a supplementary absorption agent to enter the absorption tower 7. The stabilizing tower top light component is subjected to fractionation treatment in the depropanizing tower 20 to obtain the propane product and the C4-C5 component product. The operating conditions of the stabilizing tower 15 include a tower top pressure of 1.2 MPa (G), a tower top temperature of 40℃ and a tower bottom temperature of 235℃. The operating conditions of the depropanizing tower 20 include a tower top pressure of 1.4 MPa (G), a tower top temperature of 40℃ and a tower bottom temperature of 93℃.

[0068] The product information and process parameters are shown in Table 2.

[0069] Comparative Example 1

[0070] The system of Figure 2 absorption stabilization process is carried out;

[0071] The method of the absorption stabilization process is the same as that in Embodiment 1, except that the operating pressure at the top of the absorption tower is 1.4 MPa (G), the operating pressure at the top of the desorption tower is 1.5 MPa (G), the desorption gas booster 12 is not provided, and the desorption gas at the top of the desorption tower is directly mixed with the reaction gas phase product and the saturated absorption oil at the bottom of the absorption tower to enter the compressed rich gas cooler. After the gas at the top of the absorption tower is separated by the refrigeration system at 10℃, the hydrogen-rich dry gas is obtained, pressurized to 2.35 MPa (G) by the hydrogen-rich dry gas compressor 24, sent to the PSA system to purify hydrogen, and then enters the hydrogen pipeline network.

[0072] The product information and process parameters are shown in Table 2.

[0073] Table 2 Product properties and process parameters

[0074]

[0075]

[0076] As shown in Table 1, according to the comparison of the data in Embodiment 1 and Comparative Example 1 of the present disclosure, the absorption stabilization process using the method of the present disclosure can reduce the content of C3 and above components in the hydrogen-rich dry gas by 438 kg / h, and increase the content of C2, C1 and hydrogen components by 35 kg / h in the example compared with the comparative example. Not only can the absorption stabilization process reduce the amount of absorption agent circulating use and the energy consumption of the device, but also can reduce the temperature during desorption treatment, thereby reducing the energy consumption of the system. In addition, the absorption stabilization process of the upstream product under the pressure difference formed between the absorption treatment and the desorption treatment can ensure good separation effect, 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 drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept 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 scope 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 combinations are not described again in the present disclosure.

[0079] In addition, any combination of various different embodiments of the present disclosure can also be made, 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 of an absorption stabilization process, characterized by, The method comprises: carrying out first separation on the upstream product after cooling to obtain gas phase product and liquid phase product; carrying out second separation on the gas phase product after compression and cooling to obtain rich gas phase and condensed oil phase; feeding the rich gas phase, supplementary absorbent and the liquid phase product into an absorption tower (7) to carry out absorption treatment to obtain absorption gas phase and absorption oil phase; wherein the overhead pressure of the absorption treatment is 1.7-2.8 MPa (G); carrying out refrigeration separation on the absorption gas phase through a refrigeration separation device (8) to obtain hydrogen-rich dry gas and condensed oil; feeding the hydrogen-rich dry gas into a purification unit (9) to obtain hydrogen product and PSA desorption gas; feeding the condensed oil and the condensed oil phase into a desorption tower (11) after mixing to carry out desorption treatment to obtain desorption gas and desorption oil phase; wherein the overhead pressure of the desorption treatment is 0.6-1.5 MPa (G); feeding the desorption gas into the second separation after being pressurized to 1.7-2.8 MPa (G) and being mixed with the gas phase product and the absorption oil phase; feeding the desorption oil phase into a stabilizing tower (15) and a depropanizing tower (20) in sequence to obtain propane product, C4-C5 component product and C6+ component product.

2. The method of claim 1, wherein, The method further comprises feeding the liquid phase product and the supplementary absorbent into the upper part of the absorption tower (7) and countercurrently contacting with the rich gas phase fed into the bottom part of the absorption tower (7).

3. The method of claim 1, wherein, The conditions of the absorption treatment comprise that the column bottom temperature is 12-60 ℃, the overhead pressure is 2.0-2.7 MPa (G), and the theoretical tray number of the absorption tower (7) is 5-30. The conditions of the desorption treatment comprise that the column bottom temperature is 100-140 ℃, the overhead pressure is 0.9-1.3 MPa (G), and the theoretical tray number of the desorption tower (11) is 5-35.

4. The method of claim 1, wherein, The ratio of the operating pressures of the absorption tower (7) and the desorption tower (11) is (1.8-3.1):

1.

5. The method of claim 1, wherein, The refrigeration source used by the refrigeration separation device (8) is refrigeration water; and the temperature of the refrigeration separation is 4-20 ℃.

6. The method of claim 1, wherein, The gas phase obtained after feeding the gas phase product into a rich gas compressor (3) and a low-temperature hot water heat exchanger (4) in sequence is mixed with the absorption oil phase and the desorption gas after being pressurized to obtain mixed feed; and the mixed feed is cooled through a feed cooler (5).

7. The method of claim 1, wherein, The method further comprises feeding the desorption oil phase into the stabilizing tower (15) to obtain stabilizing tower top light component and tower bottom C6+ component. The tower bottom C6+ component is at least divided into first C6+ component and second C6+ component. The first C6+ component is discharged as the C6+ component product; and the second C6+ component is fed into the absorption tower (7) as the supplementary absorbent. The stabilizing tower top light component is fed into the depropanizing tower (20) to carry out fractionation treatment to obtain the propane product and the C4-C5 component product.

8. The method of claim 7, wherein, The desorption oil phase is fed into the stabilizing tower (15) after being heat-exchanged with the tower bottom C6+ component.

9. The method of claim 7, wherein, The operating conditions of the stabilizing column (15) include: a column top pressure of 1.0-1.4 MPa (G), a column top temperature of 35-45 ℃, and a column bottom temperature of 180-250 ℃; The operating conditions of the depropanizer (20) include: a column top pressure of 1.2-1.6 MPa (G), a column top temperature of 35-45 ℃, and a column bottom temperature of 90-97 ℃.

10. The method of claim 7, wherein, The desorption column (11) is provided with a first reboiler (13) in the middle and a second reboiler (14) at the bottom; the depropanizer is provided with a third reboiler (23) at the bottom; The method further includes using the column bottom C6+ component as a heat source for the first reboiler (13), the second reboiler (14), and the third reboiler (23).

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