Method for absorbing and stabilizing process

Abstract

The invention relates to a method for absorbing and stabilizing a process, which comprises the following steps of: treating an upstream product by a multi-stage cooling, separating and boosting device in sequence to obtain a gas-rich phase and a condensed oil phase; carrying out absorption treatment on the rich gas phase, the supplementary absorbent and the liquid phase product under the condition of 1.7-2.8 MPa (G) to obtain an absorption gas phase and an absorption oil phase; freezing and separating the absorption gas phase to obtain hydrogen-rich dry gas and condensed oil; mixing the condensed oil and the condensed oil phase, and performing desorption treatment under the condition of 0.6-1.5 MPa (G) to obtain desorbed gas and a desorbed oil phase; and returning the desorbed gas to a multi-stage cooling, separating and boosting device, and treating the desorbed oil phase through a stabilizing tower and a depropanizing tower in sequence to obtain a propane product, a C4-C5 component product and a C6 + component product. According to the invention, the absorption stabilization process is carried out under the condition of differential pressure formed between the absorption treatment and the desorption treatment, so that the energy consumption of the system can be reduced while the quality of the product is ensured.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical industry, and in particular, to a method for an absorption stabilization process. Background Art

[0002] In recent years, with the increasing pressure on the comprehensive utilization of petrochemical products and energy conservation and emission reduction in domestic plants, optimizing the absorption stabilization process to achieve the purpose of improving the purity of dry gas components below C2, increasing the yield of liquefied gas and C3 components and reducing the energy consumption of system operation has become a direction of extensive and in-depth research. However, in most of the process units currently operating with absorption stabilization systems, the pressures of the absorption tower and the desorption tower are interrelated and basically close, and most of them are double-tower processes, and the optimization of the absorption stabilization process is also mostly carried out on this basis. The problem is that product quality improvement and energy conservation and consumption reduction always restrict each other, and it is difficult to achieve both. Summary of the invention

[0003] The purpose of the present disclosure is to provide a method for stabilizing an absorption process to solve the problem in the prior art that it is difficult to reduce system energy consumption while improving product quality.

[0004] In order to achieve the above-mentioned purpose, the present disclosure provides a method for an absorption stabilization process, which comprises: subjecting an upstream product to a cooling, separation and pressure-increasing device to treatment to obtain a gas phase product and a liquid phase product; mixing the gas phase product, the desorbed gas and the absorbed oil phase to obtain a pre-treated material; wherein the pressure of the pre-treated material is 1.9 to 3.0 MPa (G); the number of stages of the cooling, separation and pressure-increasing device is two or more; cooling the pre-treated material and performing oil-gas separation to obtain a rich gas phase and a condensed oil phase; allowing the rich gas phase, the liquid phase product and the supplementary absorbent to enter an absorption tower for absorption treatment to obtain an absorbed gas phase and the desorbed oil phase; 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 freeze separation by a freeze separation device to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is treated by a purification unit to obtain a hydrogen product and a PSA desorbed gas; the condensed oil is mixed with the condensed oil phase and then enters a desorption tower for desorption treatment to obtain the desorbed gas and desorbed oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa(G); the desorbed oil phase is sequentially treated by a stabilization tower and a depropanizer to obtain a propane product, a C4-C5 component product and a C6+ component product.

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

[0006] Optionally, the method further comprises allowing the liquid phase product and the supplemental absorbent to enter from the upper portion of the absorption tower and to countercurrently contact with the rich gas phase entering from the bottom of the absorption tower.

[0007] Optionally, the conditions for the absorption treatment include: the bottom temperature of the tower is 12 to 60°C, the top pressure of the tower is 2.0 to 2.7 MPa (G), and the theoretical number of plates of the absorption tower is 5 to 30; the conditions for the desorption treatment include: the bottom temperature of the tower is 100 to 140°C, the top pressure of the tower is 0.9 to 1.3 MPa (G), and the theoretical number of plates of the desorption tower is 5 to 35.

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

[0009] Optionally, the cold source used by the freezing separation device is chilled water; the temperature of the freezing separation is 4 to 20°C.

[0010] Optionally, the gaseous product obtained by the cooling, separation and pressurization device is mixed with the absorption oil after heat exchange in a low-temperature hot water heat exchanger to obtain the pretreated material; and the pretreated material is cooled in a feed cooler.

[0011] Optionally, the method also includes: subjecting the desorbed oil phase to treatment in a stabilization tower to obtain a light component at the top of the tower and a C6+ component at the bottom of the tower; separating the C6+ component at the bottom of the tower into at least a first C6+ component and a second C6+ component; discharging the first C6+ component as the C6+ component product; using the second C6+ component as a supplementary absorbent for an absorption tower; and allowing the light component at the top of the tower to enter the depropanizer for fractionation treatment to obtain the propane product and the C4-C5 component product.

[0012] Optionally, after the desorbed oil phase exchanges heat with the C6+ component at the bottom of the tower, it enters the stabilization tower; the operating conditions of the stabilization tower include: the top pressure is 1.0-1.4 MPa (G), the top temperature is 35-45°C, and the bottom temperature is 180-250°C; the operating conditions of the depropanizer include: the top pressure is 1.2-1.6 MPa (G), the top temperature is 35-45°C, and the bottom temperature is 90-97°C.

[0013] Optionally, a first reboiler is provided in the middle of the desorption tower and a second reboiler is provided at the bottom; a third reboiler is provided at the bottom of the depropanizer; the method also includes exchanging heat between the C6+ component at the bottom of the tower and the desorption oil, which serves as a heat source for the first reboiler, the second reboiler and the third reboiler.

[0014] Through the above technical scheme, 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 absorbent recycled and the energy consumption of the device; and can improve the desorption performance of components below C2 by operating the desorption tower at a lower pressure, thereby reducing the temperature during the desorption process and reducing the energy consumption of the system. In addition, the upstream product is subjected to an absorption stabilization process under the differential pressure conditions formed between the absorption process and the desorption process, which can ensure a good separation effect and thus ensure the quality of the obtained product.

[0015] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 Schematic diagram of a system for an absorption stabilization process disclosed herein.

[0018] Figure 2 Schematic diagram of a system of an absorption stabilization process according to a comparative example of the present disclosure.

[0019] Description of Reference Numerals

[0020] 1. primary cooler; 2. primary liquid separator; 3. primary compressor; 4. secondary cooler; 5. secondary liquid separator; 6. secondary compressor; 7. tertiary cooler; 8. tertiary liquid separator; 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 cooler; 17. desorption tower; 18. first reboiler; 19. second reboiler; 20. stabilization tower; 21. oil-gas condenser at the top of stabilization tower; 22. reflux tank of stabilization tower; 23. reboiler of stabilization tower; 24. supplementary absorbent cooler; 25. depropanizer; 26. oil-gas condenser at the top of depropanizer; 27. reflux tank of depropanizer; 28. third reboiler; 29. ​​hydrogen-rich dry gas compressor. DETAILED DESCRIPTION

[0021] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0022] In the present disclosure, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of a device in normal use. Figure 1 In the drawing direction, "inside" and "outside" refer to the outline of the device. In addition, the terms "first, second, third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first, second, third" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0023] like Figure 1 As shown, the present disclosure provides a method for an absorption stabilization process, which includes: subjecting an upstream product to a cooling, separation and pressure-increasing device to treatment to obtain a gas phase product and a liquid phase product; mixing the gas phase product, the desorbed gas and the absorbed oil phase to obtain a pre-treated material; wherein the pressure of the pre-treated material is 1.9 to 3.0 MPa (G); the number of stages of the cooling, separation and pressure-increasing device is two or more; cooling the pre-treated material to perform oil-gas separation to obtain a gas-rich phase and a condensed oil phase; allowing the gas-rich phase, the liquid phase product and the supplementary absorbent to enter an absorption tower 13 for absorption treatment to obtain an absorbed gas phase and the absorbed oil phase; wherein the absorption treatment The tower top pressure is 1.7-2.8 MPa (G); the absorption gas phase is subjected to freeze separation by a freeze separation device 14 to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is treated by a purification unit 15, and the obtained purified hydrogen is sent to a hydrogen pipeline network, and the obtained PSA desorbed gas is discharged; the condensed oil is mixed with the condensed oil phase and then enters a desorption tower 17 for desorption treatment to obtain the desorbed gas and desorbed oil phases; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa (G); the desorbed oil phase is sequentially treated by a stabilization tower 20 and a depropanizer 25 to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0024] Through the above technical scheme, 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 absorbent recycled and the energy consumption of the device. The desorption performance of components below C2 can be improved by operating the desorption tower at a lower pressure, thereby reducing the temperature during the desorption process and reducing the energy consumption of the system. In addition, the upstream product is subjected to an absorption stabilization process under the differential pressure conditions formed between the absorption process and the desorption process, which can ensure a good separation effect and thus ensure the quality of the obtained product.

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

[0026] In one embodiment, each stage of the cooling and separation device in the present disclosure 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 and separation device is first cooled by the cooler and then enters the separator for gas-liquid separation, and the obtained gas phase is pressurized by the compressor. Among them, the separator is a conventional choice in the field, and this application does not make special requirements. It only needs to ensure that the device can separate gas and liquid. For example, the separator of the present disclosure is a gas-liquid separation tower.

[0027] Among them, the number of stages of the cooling and separation device is preferably three, namely a first-stage cooling and separation boosting device, a second-stage cooling and separation boosting device and a third-stage cooling and separation boosting device.

[0028] In a specific embodiment, the present invention first allows the upstream product to enter a primary cooler 1 for preliminary cooling, and then enters a primary liquid separator 2 for separation to obtain a first gas phase and a first liquid phase, and the first gas phase is pressurized by a primary compressor 3; the pressurized first gas phase is cooled by a secondary cooler 4 and sent to a secondary liquid separator 5 for separation to obtain a second gas phase and a second liquid phase, and the second gas phase is pressurized by a secondary compressor 6; the pressurized second gas phase is mixed with the desorbed gas and sent to a tertiary cooler 7 for cooling, and then the cooled mixed material is sent to a tertiary liquid separator 8 for separation to obtain a third gas phase and a third liquid phase, and the third gas phase is pressurized to 1.9 to 3.0 MPa (G) by a tertiary compressor 9 and then heat exchanged by a low-temperature hot water heat exchanger 10; then the mixed material after heat exchange is mixed with the absorption oil phase to obtain a pretreated material, and the pretreated material is cooled to 12 to 60°C by a feed cooler 11.

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

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

[0031] Through the above-mentioned implementation, when the upstream product with a higher temperature is separated, the components in the upstream product will have more components mixed in the gas phase under high temperature conditions. Therefore, the gas phase product produced by 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 output of dry gas, the present invention increases the pressure of the gas phase product while reducing the temperature of the gas phase through a three-stage cooling separation device to increase the solubility of the C3 component and components above C3 in the liquid phase product; and, the temperature of the mixed gas phase is reduced by a low-temperature hot water heat exchanger 10, which can further increase the solubility of the C3 component and components above C3 in the liquid phase product. In addition, since the absorption oil phase and the desorbed gas are both produced at a relatively low temperature, the temperature of the mixed feed is also relatively low, which can reduce the load of the mixed feed through the feed cooler 11 and reduce the energy consumption of the entire system.

[0032] In one embodiment, the pre-treated material cooled by the feed cooler 11 enters the oil-gas separator 12 for oil-gas separation, wherein the oil-gas separator 12 used in the present disclosure is a conventional choice in the art, and this application does not make any special requirements. In this embodiment, after the pre-treated material undergoes a series of temperature reduction and pressure increase, 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 gas-rich phase.

[0033] In one embodiment, the method further includes allowing the liquid phase product and the supplementary absorbent to enter the absorption tower 13 from the upper part of the absorption tower 13; allowing the rich gas phase separated by the oil-gas separator 12 to enter the absorption tower 13 from the bottom of the absorption tower 13; under the action of gravity, the liquid phase product and the supplementary absorbent are in countercurrent contact with the rich gas phase.

[0034] In order to enhance the effect of countercurrent contact, a liquid product injection device and a supplementary absorbent injection device may be provided at the upper portion of the absorption tower 13 , and a gas distributor may be provided at the bottom of the absorption tower 13 .

[0035] Among them, the present disclosure sets 1 to 4 middle section coolers 16 in the middle of the absorption tower 13. Preferably, two middle section coolers 16 are set, and are respectively set at 1 / 3 and 2 / 3 of the absorption tower, with two tower plates floating up and down.

[0036] A plurality of trays are sequentially arranged in the absorption tower 13 from top to bottom. Specifically, the number of trays in the absorption tower 13 is 5 to 30, preferably 8 to 20.

[0037] In this embodiment, by countercurrent contact between the rich gas phase and the liquid phase product and the supplementary absorbent, a small amount of C3 components and components above C3 in the rich gas phase can be further reduced, thereby further improving the quality of the dry gas. In addition, the selective arrangement of an injection device and a gas distributor in the absorption tower 13 can further enhance the effect of countercurrent contact; the arrangement of the middle cooler 16 can ensure the stability of the temperature in the absorption tower 13; the arrangement of multiple plates can extend the countercurrent contact time between the gas phase and the liquid phase, thereby improving the absorption effect. In addition, through the above arrangement, the conditions for the absorption treatment can be maintained at a tower bottom temperature of 12 to 60°C, preferably 15 to 42°C; the tower top pressure is preferably 2.0 to 2.7 MPa (G), and more preferably 2.1 to 2.6 MPa (G). In this embodiment, the absorption treatment is carried out under the above conditions, which can avoid excessive absorption in the absorption treatment, thereby reducing the energy consumption of the device while ensuring the absorption treatment effect.

[0038] The purification unit 15 used in the present disclosure is a conventional choice in the art, and this application does not make special requirements. For example, the purification unit used in the present disclosure is a PSA unit. The purity of the hydrogen obtained after treatment by the PSA unit can reach more than 99v%, which can meet the use conditions of most hydrogen-using devices.

[0039] In one embodiment, the freezing separation device 14 used in the present disclosure includes a hydrogen-rich dry gas freezer and an aromatic hydrocarbon recovery tank. When the hydrogen-rich dry gas enters the freezing separation device 14, it first passes through the hydrogen-rich dry gas freezer to rapidly reduce the temperature, wherein the aromatic hydrocarbons brought 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 freezing separation temperature is 4 to 20°C, preferably 6 to 12°C. In this embodiment, the cold source used by the hydrogen-rich dry gas freezer can be a heat exchanger with chilled water as the cold source, or it can be an ammonia or propane, propylene, ethylene refrigerator, preferably a heat exchanger with chilled water as the cold source.

[0040] In one embodiment, the desorption tower 17 uses cold feed from the top of the tower, and the feed temperature is 10-60°C, preferably 35-45°C; a first reboiler 18 is arranged in the middle of the desorption tower 17, and a second reboiler 19 is arranged 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 for the desorption treatment include: the bottom temperature is 100-140°C, preferably 110-130°C; the top pressure is preferably 0.9-1.3 MPa(G), more preferably 1.05-1.2 MPa(G); the theoretical plate number of the desorption tower 17 is 5-35.

[0042] Through the above implementation, the cold feed of the desorption tower 17 can make the mixed material gradually cool down during the process of running from the bottom of the tower to the top of the tower, thereby preventing the components therein from being entrained by the desorption gas, thereby ensuring the quality of the liquefied gas and C6+ component products.

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

[0044] In one embodiment, the method further includes: subjecting the desorbed oil phase to treatment in a stabilization tower 20 to obtain a light component at the top of the stabilization tower and a C6+ component at the bottom of the tower; separating the C6+ component at the bottom of the tower into at least a first C6+ component and a second C6+ component; discharging the first C6+ component as the C6+ component product; allowing the second C6+ component to enter the absorption tower 13 as the supplementary absorbent; and allowing the light component at the top of the stabilization tower to enter the depropanizer 25 for fractionation treatment to obtain the propane product and the C4-C5 component product.

[0045] Wherein, a mid-section cooler 16 is arranged on the pipeline when the second C6+ component enters the absorption tower 13 as the supplementary absorbent, so as to ensure that the temperature of the supplementary absorbent drops to 4-20°C, preferably 6-12°C.

[0046] Wherein, at least part of the C6+ components at the bottom of the tower are sent to the stabilization tower reboiler 23 for heating and then returned to the stabilization tower 20 for treatment.

[0047] The desorbed oil phase exchanges heat with the C6+ component and then enters the stabilization tower 20 for treatment.

[0048] Among them, the C6+ component product, the bottom C6+ component, the first C6+ component and the second C6+ component are mainly composed of C6~C9 components; the top light component is mainly composed of C3~C5 components.

[0049] The operating conditions of the stabilization tower 20 include: a tower top pressure of 1.0-1.4 MPa (G), a tower top temperature of 35-45° C., and a tower bottom temperature of 180-250° C.

[0050] Among them, the light components at the top of the stabilization tower 20 are first cooled by the stabilization tower top oil and gas condenser 21 and then refluxed into the stabilization tower reflux tank 22, and a part of the reflux products are circulated to the stabilization tower 20, and another part of the reflux products enter the depropanizer 25.

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

[0052] Wherein, a third reboiler 28 is provided at the bottom of the depropanizer.

[0053] The method further includes, after the tower bottom C6+ component is heat exchanged with the desorbed oil phase, the heat source is used for 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 tower bottom C6+ component can be heat exchanged with the desorbed oil phase first, and then heat exchanged through the second reboiler 19, the third reboiler 28 and the first reboiler 18 in sequence.

[0054] The top material of the depropanizer is cooled by the depropanizer top oil gas condenser 26 and then refluxed into the depropanizer reflux tank 27. A part of the reflux product is circulated to the depropanizer 25, and another part of the reflux product is discharged from the system as a propane product.

[0055] The system used in the present disclosure also includes a low-temperature hot water system for recovering low-temperature heat in petrochemical equipment. The recovered energy can be used for heating equipment and pipelines or for power generation.

[0056] In another embodiment, the depropanizer 25 of the present disclosure can be replaced by a debutanizer, and another portion of the reflux product is processed in the debutanizer 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 product requirements.

[0057] In one embodiment, if Figure 1 As shown, the method of absorption stabilization process includes:

[0058] The upstream product is allowed to enter the primary cooler 1 for preliminary cooling, and then enters the primary liquid separator 2 for separation to obtain a first gas phase and a first liquid phase, and the first gas phase is pressurized by the primary compressor 3; the pressurized first gas phase is cooled by the secondary cooler 4 and sent to the secondary liquid separator 5 for separation to obtain a second gas phase and a second liquid phase, and the second gas phase is pressurized by the secondary compressor 6; the pressurized second gas phase is mixed with the desorbed gas and sent to the tertiary cooler 7 for cooling, and then the cooled mixed material is sent to the tertiary liquid separator 8 for separation to obtain a third gas phase and a third liquid phase, and the third gas phase is pressurized to 1.9-3.0 MPa (G) by the tertiary compressor 9 and then heat exchanged by the low-temperature hot water heat exchanger 10; then the mixed material after heat exchange is mixed with the absorption oil phase to obtain a pretreated material, and the pretreated material is cooled to 12-60°C by the feed cooler 11.

[0059] The pretreated material is fed into a feed cooler 11 for oil-gas separation to obtain a gas-rich phase and a condensed oil phase; the gas-rich phase, the supplementary absorbent and the liquid phase product are fed 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 bottom temperature of 12 to 60°C, a top pressure of 1.7 to 2.8 MPa (G), and a theoretical plate number of 5 to 30 in the absorption tower; the absorption gas phase is frozen to 4 to 20°C by a freezing separation device 14 and then frozen and separated , obtaining hydrogen-rich dry gas and condensed oil; subjecting the hydrogen-rich dry gas to treatment by a purification unit 15, and sending the obtained hydrogen product into a hydrogen pipeline network; subjecting the condensed oil to mixing with the condensed oil phase and entering a desorption tower 17 for desorption treatment, to obtain desorbed gas and desorbed oil phase; wherein the desorption treatment conditions include: a tower bottom temperature of 100 to 140°C, a tower top pressure of 0.6 to 1.5 MPa (G); and returning the desorbed gas to the first-stage cooling, separation and pressurization device, the second-stage cooling, separation and pressurization device, or the third-stage cooling, separation and pressurization device.

[0060] The desorbed oil phase is processed by the stabilization 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 heat exchanged with the desorbed oil phase, and then sequentially heat exchanged by the second reboiler 19, the third reboiler 28 and the first reboiler 18 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 entered into the absorption tower 13 as a supplementary absorbent; the light component at the top of the stabilization tower is The depropanizer 25 is fractionated to obtain the propane product, C4-C5 component product and C6+ component product; wherein the operating conditions of the stabilization tower 20 include: a tower top pressure of 1.0-1.4 MPa (G), a tower top temperature of 35-45°C, and a tower bottom temperature of 180-250°C; the operating conditions of the depropanizer 25 include: a tower top pressure of 1.2-1.6 MPa (G), a tower top temperature of 35-45°C, and a tower bottom temperature of 90-97°C.

[0061] The method provided by the present invention is further described below by means of specific examples, but the present invention is not limited thereby. The upstream product used in the examples is the product of a certain 800,000 tons / year oil refinery, and the specific properties are shown in Table 1.

[0062] Table 1 Properties of upstream products

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

[0064] Example 1

[0065] use Figure 1 The method for carrying out absorption stabilization process in the system includes:

[0066] The upstream reaction product is allowed to enter the primary cooler 1 for preliminary cooling, and then enter the primary liquid separator 2 for separation to obtain the first gas phase and the first liquid phase, and the first gas phase is pressurized by the primary compressor 3; the pressurized first gas phase is cooled by the secondary cooler 4 and sent to the secondary liquid separator 5 for separation to obtain the second gas phase and the second liquid phase, and the second gas phase is pressurized by the secondary compressor 6; the pressurized second gas phase is mixed with the desorbed gas and sent to the tertiary cooler 7 for cooling, and then the cooled mixed material is sent to the tertiary liquid separator 8 for separation to obtain the third gas phase and the third liquid phase, and the third gas phase is pressurized to 2.6MPa (G) by the tertiary compressor 9 and then heat exchanged by the low-temperature hot water heat exchanger 10; then the mixed material after heat exchange is mixed with the absorbed oil phase to obtain the pretreated material, and the pretreated material is cooled to 40°C by the feed cooler 11. The pretreated material enters the feed cooler 11 for oil-gas separation to obtain a rich gas phase and a condensed oil phase;

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

[0068] The desorbed oil phase is heat exchanged with the C6+ component at the bottom of the stabilization tower at 145°C and then enters the stabilization tower 20 for treatment 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 stabilization tower 20 is first heat exchanged with the desorbed oil phase, and then heat exchanged with the second reboiler 19, the third reboiler 28 and the first reboiler 18 in sequence to cool to 40°C, and then separated into a first C6+ component and a second C6+ component; the first C6+ component is discharged as a C6+ component product; the second C The C6+ component enters the absorption tower 13 as a supplementary absorbent; the light component at the top of the stabilization tower enters 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 stabilization tower 20 include: pressure of 1.2 MPa (G), tower top temperature of 40°C, tower bottom temperature of 235°C; the operating conditions of the depropanizer 25 include: pressure of 1.4 MPa (G), tower top temperature of 40°C, tower bottom temperature of 93°C.

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

[0070] Comparative Example 1

[0071] use Figure 2 The system is subjected to absorption stabilization process;

[0072] The method of absorption stabilization process is the same as that of Example 1, except that the top operating pressure of the absorption tower in this process is 1.4MPa(G), the top operating pressure of the desorption tower is 1.5MPa(G), and no three-stage cooling and separation device (i.e., three-stage cooler 7, three-stage liquid separator 8 and three-stage compressor 9) is set. The desorbed 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 and then fed into the compressed rich gas cooler. The top gas of the absorption tower is frozen to 10°C by the refrigeration system and separated to obtain hydrogen-rich dry gas, which is pressurized to 2.35MPa(G) by the hydrogen-rich dry gas compressor 29 and sent to the PSA system for hydrogen purification and then fed 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 of the present disclosure and Comparative Example 1, it can be seen that 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 in the embodiment by 438kg / h, and increase C2, C1 and hydrogen components by 35kg / h compared with the comparative example, which can not only reduce the amount of absorbent recycling and reduce the energy consumption of the device, but also reduce the temperature during the desorption process, thereby reducing the energy consumption of the system. In addition, the absorption stabilization process is carried out on the upstream product under the differential pressure conditions formed between the absorption process and the desorption process, which can ensure a good separation effect and thus ensure the quality of the obtained product.

[0077] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0079] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for absorbing a stabilization process, characterized in that: The method includes: The upstream product is processed by a cooling, separation and pressurizing device to obtain a gas phase product and a liquid phase product; the gas phase product, the desorbed gas and the absorbed oil phase are mixed to obtain a pre-treated material; wherein the pressure of the pre-treated material is 1.9 to 3.0 MPa (G); the number of stages of the cooling, separation and pressurizing device is two or more; The pretreated material is cooled and then subjected to oil-gas separation to obtain a gas-rich phase and a condensed oil phase; the gas-rich phase, the liquid phase product and the supplementary absorbent are introduced 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); the absorption gas phase is subjected to freezing separation by a freezing separation device (14) to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is subjected to treatment by a purification unit (15) to obtain a hydrogen product and a PSA desorbed gas; The condensed oil is mixed with the condensed oil phase and then enters a desorption tower (17) for desorption treatment to obtain the desorbed gas and desorbed oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa (G); the desorbed oil phase is sequentially processed through a stabilization tower (20) and a depropanizer (25) to obtain a propane product, a C4-C5 component product and a C6+ component product.

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

3. The method according to claim 1, characterized in that The method further comprises allowing the liquid phase product and the supplementary absorbent to enter from the upper part of the absorption tower (13) and to countercurrently 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 is 12 to 60°C, the top pressure is 2.0 to 2.7 MPa (G), and the theoretical plate number of the absorption tower (13) is 5 to 30; The desorption treatment conditions include: the tower bottom temperature is 100-140°C, the tower top pressure is 0.9-1.3 MPa (G), and the theoretical plate number of the desorption tower (17) is 5-35.

5. The method according to claim 1, characterized in that The ratio of the operating pressures of the absorption tower (13) and the desorption tower (17) is (1.1-3.1):

1.

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

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

8. The method according to claim 1, characterized in that The method further comprises subjecting the desorbed oil phase to treatment in a stabilization tower (20) to obtain a light component at the top of the tower and a C6+ component at the bottom of the tower; Separate the tower bottom C6+ component into at least a first C6+ component and a second C6+ component; Discharging the first C6+ component as the C6+ component product; Using the second C6+ component as a supplementary absorbent for the absorption tower (13); The light component at the top of the tower is fed into the depropanizer (25) for fractionation treatment to obtain the propane product and the C4-C5 component product.

9. The method according to claim 7, characterized in that: After the desorbed oil phase exchanges heat with the C6+ components at the bottom of the tower, it enters the stabilization tower (20); The operating conditions of the stabilization tower (20) include: a tower top pressure of 1.0 to 1.4 MPa (G), a tower top temperature of 35 to 45° C., and a tower bottom temperature of 180 to 250° C.; The operating conditions of the depropanizer (25) include: a tower top pressure of 1.2-1.6 MPa (G), a tower top temperature of 35-45° C., and a tower bottom temperature of 90-97° C.

10. The method according to claim 7, 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 depropanizer is provided with a third reboiler (28) at the bottom; The method further includes using the tower bottom C6+ component as a heat source for the first reboiler (18), the second reboiler (19) and the third reboiler (28) after heat exchange with the desorbed oil.

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