Method for absorbing and stabilizing process

Abstract

The present disclosure relates to a method of an absorption stabilization process, the method comprising: cooling, boosting and separating an upstream product 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 treating the desorption 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] The absorption and stabilization process is a product separation unit for light hydrocarbon conversion, catalytic cracking, delayed coking and hydrocracking units in the field of petroleum processing. The system is mainly composed of an absorption tower, a desorption tower and a stabilization tower and corresponding auxiliary equipment such as cold and heat exchange equipment and pumps. Its main purpose is to use absorption and distillation methods to separate rich gas and crude gasoline into dry gas (H2, C2 and below), liquefied gas and gasoline with vapor pressure that meets product specifications.

[0003] In recent years, with the increasing pressure on the comprehensive utilization of petrochemical products and energy conservation and emission reduction in domestic equipment, continuously optimizing the absorption stabilization system process, refining the operating conditions and proposing technical transformation measures to achieve the goal 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, and some practical results have been achieved.

[0004] At present, most of the process equipment containing absorption stabilization systems in operation have pressures of the absorption tower and the desorption tower that are interrelated and basically close. 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 that arises is that product quality improvement and energy conservation and consumption reduction always restrict each other, and it is difficult to have both. Summary of the invention

[0005] 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.

[0006] In order to achieve the above-mentioned purpose, the present disclosure provides a method for an absorption stabilization process, which comprises: cooling the 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; allowing the rich gas phase, the supplementary absorbent and the liquid phase product to enter 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 to 2.8 MPa (G); allowing the absorption gas phase to be frozen and separated by a freezing separation device to obtain a hydrogen-rich dry gas and a condensed oil phase. Oil; subjecting the hydrogen-rich dry gas to treatment by a purification unit to obtain a hydrogen product and a PSA desorbed gas; subjecting the condensed oil to mixing with the condensed oil phase and then entering a desorption tower for desorption treatment to obtain desorbed gas and desorbed oil phases; wherein the tower top pressure for desorption treatment is 0.6-1.5 MPa(G); pressurizing the desorbed gas to 1.7-2.8 MPa(G) and then mixing with the gas phase product and the absorbed oil phase for the second separation; subjecting the desorbed oil phase to treatment by a stabilization tower and a depropanizer in sequence to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0007] 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.

[0008] 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.

[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; the temperature of the freezing separation is 4 to 20°C.

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

[0012] 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 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 as the supplementary absorbent; allowing the light component at the top of the stabilization tower to enter the depropanizer for fractionation treatment to obtain the propane product and the C4-C5 component product.

[0013] Optionally, the desorbed oil phase enters the stabilization tower after heat exchange with the C6+ components at the bottom of the tower.

[0014] Optionally, the operating conditions of the stabilization tower include: a top pressure of 1.0 to 1.4 MPa (G), a top temperature of 35 to 45°C, and a bottom temperature of 180 to 250°C; the operating conditions of the depropanizer include: a top pressure of 1.2 to 1.6 MPa (G), a top temperature of 35 to 45°C, and a bottom temperature of 90 to 97°C.

[0015] 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 using the C6+ component at the bottom of the tower as a heat source for the first reboiler, the second reboiler and the third reboiler.

[0016] 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.

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

[0018] 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:

[0019] Figure 1 Schematic diagram of a system for an absorption stabilization process disclosed herein.

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

[0021] Description of Reference Numerals

[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 tower; 8 refrigeration separation device; 9 purification unit; 10 middle section cooler; 11 desorption tower; 12 desorption gas booster; 13 first reboiler; 14 second reboiler; 15 stabilization tower; 16 stabilization tower top oil-gas condenser; 17 stabilization tower reflux tank; 18 stabilization tower reboiler; 19 supplementary absorbent cooler; 20 depropanizer; 21 depropanizer top oil-gas condenser; 22 depropanizer reflux tank; 23 third reboiler; 24 hydrogen-rich dry gas compressor. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] like Figure 1As shown, the present disclosure provides a method for an absorption stabilization process, which includes: cooling the 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; allowing the rich gas phase, the supplementary absorbent and the liquid phase product to enter 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 to 2.8 MPa (G); subjecting the absorption gas phase to a freezing separation device 8 for freezing separation to obtain a hydrogen-rich dry gas and condensed oil; subjecting the hydrogen-rich dry gas to a PSA Unit 9 is used for treatment, and the purified hydrogen obtained 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 enters the desorption tower 11 for desorption treatment to obtain desorbed gas and desorbed oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa (G); the desorbed gas is pressurized to 1.7-2.8 MPa (G) and then mixed with the gas phase product and the absorbed oil phase for the second separation; the desorbed oil phase is processed in turn by the stabilization tower 15 and the depropanizer 20 to obtain a propane product, a C4-C5 component product and a C6+ component product.

[0026] Through the above technical scheme, 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 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, so as to reduce the temperature during the desorption process and thereby reduce 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 thereby ensure the quality of the obtained product.

[0027] 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.

[0028] In one embodiment, the present disclosure first allows the upstream product to enter the reaction product cooler 1 for preliminary cooling, and then enter the reaction product separator 2 for the first separation. Among them, the reaction product cooler 1 and the reaction product separator 2 are conventionally selected in the art, and this application does not make special requirements, and only requires a device that can cool the upstream product and a device that can separate gas and liquid.

[0029] In one embodiment, the obtained gas phase product is pressurized to 1.9-3.0 MPa (G) by the rich gas compressor 3, and then sent to the low temperature hot water heat exchanger 4 for heat exchange, so that the temperature of the gas phase product is reduced to 75-95° C. 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 heat exchanged by the low-temperature hot water heat 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° C. by a feed cooler 5.

[0031] Through the above-mentioned implementation, when the upstream product with a higher temperature is subjected to the first separation, 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 yield of dry gas, the present disclosure increases the pressure in the gas phase product through the rich gas compressor 3 to increase the solubility of the C3 component 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 heat exchanger 4, thereby further increasing 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 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 a second separation, wherein the oil-gas separator 6 used in the present disclosure is a conventional choice in the art, and the present application does not make any special requirements. In this embodiment, after the mixed feed after a series of temperature reduction and pressure increase is subjected to a second separation, 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 separated by the reaction product separator 2 and the supplementary absorbent to enter the absorption tower 7 from the upper part of the absorption tower 7; allowing the rich gas phase separated by the oil-gas separator 6 to enter the absorption tower 7 from the bottom of the absorption tower 7; 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 7 , and a gas distributor may be provided at the bottom of the absorption tower 7 .

[0035] Among them, the present disclosure sets 1 to 4 middle section coolers 10 in the middle of the absorption tower 7. Preferably, two middle section coolers 10 are set, and are respectively set at 1 / 3 and 2 / 3 of the absorption tower, with two fast tower plates floating up and down.

[0036] A plurality of trays are sequentially arranged in the absorption tower 7 from top to bottom. Specifically, the number of trays in the absorption tower 7 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 7 can further enhance the effect of countercurrent contact; the arrangement of the middle cooler 10 can ensure the stability of the temperature in the absorption tower 7; the arrangement of multiple plates can extend the residence time of the countercurrent contact 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 9 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 8 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 8, 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 11 uses cold feed from the top of the tower, and the feed temperature is 10-60°C, preferably 35-45°C; a first reboiler 13 is arranged in the middle of the desorption tower 11, and a second reboiler 14 is arranged 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 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 11 is 5-35.

[0042] Through the above implementation, the cold feed of the desorption tower can make the temperature of the mixed material gradually decrease 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 7 and the desorption tower 11 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 15 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 7 as the supplementary absorbent; and allowing the light component at the top of the stabilization tower to enter the depropanizer 20 for fractionation treatment to obtain the propane product and the C4-C5 component product.

[0045] At least part of the C6+ components at the bottom of the tower are heated in the stabilization tower reboiler 18 and then returned to the stabilization tower 15 to maintain the temperature stability of the stabilization tower.

[0046] The desorbed oil phase exchanges heat with the C6+ components at the bottom of the tower and then enters the stabilization tower 15 for treatment.

[0047] 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.

[0048] The operating conditions of the stabilization tower 15 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.

[0049] Among them, the light components at the top of the stabilization tower 15 are first cooled by the stabilization tower top oil and gas condenser 16 and then refluxed into the stabilization tower reflux tank 17, and a part of the reflux products are circulated to the stabilization tower 15, and another part of the reflux products enter the depropanizer 20.

[0050] The operating conditions of the depropanizer 20 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.

[0051] Wherein, a third reboiler 23 is provided at the bottom of the depropanizer.

[0052] The method further includes using the tower bottom C6+ component as a heat source for the first reboiler 13, the second reboiler 14 and the third reboiler 23, so that the tower bottom C6+ component can exchange heat with the absorption tower interruption material, the absorption tower bottom material and the depropanizer bottom material. In this embodiment, in order to further utilize the temperature of each section, the tower bottom C6+ component can firstly exchange heat with the desorption oil phase, and then sequentially pass through the second reboiler 14, the third reboiler 23 and the first reboiler 13 for heat exchange.

[0053] The top material of the depropanizer is cooled by the depropanizer top oil gas condenser 21 and then refluxed into the depropanizer reflux tank 22. A part of the reflux product is circulated to the depropanizer 20, and another part of the reflux product is discharged from the system as a propane product.

[0054] 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.

[0055] In another embodiment, the depropanizer 20 of the present disclosure can be replaced by a debutanizer, and in this case, 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 20 and the debutanizer can be flexibly replaced according to product requirements.

[0056] In one embodiment, if Figure 1 As shown, the method of absorption stabilization process includes:

[0057] The upstream product enters the reaction product cooler 1 for preliminary cooling, and then enters the reaction product separator 2 for the first separation to obtain a gas phase product and a liquid phase product; the obtained gas phase product is pressurized to 1.9-3.0 MPa (G) by the rich gas compressor 3, and then sent to the low-temperature hot water heat exchanger 4 for heat exchange to reduce the temperature of the gas phase product to 75-95°C. Among them, the low-temperature hot water heat exchanger 4 uses the gas phase product as a heat source and water as a cold source. The gas phase exchanged 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 subjected to a second separation to obtain a rich gas phase and a condensed oil phase;

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

[0059] The desorbed oil phase is processed by the stabilization tower 15 to obtain a light component at the top of the stabilization tower and a C6+ component at the bottom of the tower; the C6+ component at the bottom of the tower is first heat exchanged with the desorbed oil phase, and then sequentially heat exchanged through the second reboiler 14, the third reboiler 23 and the first reboiler 13 to be separated 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 7 as a supplementary absorbent; the top of the stabilization tower is The light component enters the depropanizer 20 for fractionation treatment to obtain the propane product and the C4-C5 component product; wherein, the operating conditions of the stabilization 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; the operating conditions of the depropanizer 20 include: the tower top pressure is 1.2-1.6 MPa (G), the tower top temperature is 35-45°C, and the tower bottom temperature is 90-97°C.

[0060] 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.

[0061] Table 1 Properties of upstream products

[0062] 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

[0063] Example 1

[0064] use Figure 1 The method for carrying out absorption stabilization process in the system includes:

[0065] The upstream product enters the reaction product cooler 1 for preliminary cooling, and then enters the reaction product separator 2 for the first separation to obtain a gas phase product and a liquid phase product; the obtained gas phase product is pressurized to 2.6MPa (G) by the rich gas compressor 3, and then sent to the low-temperature hot water heat exchanger 4 for heat exchange to reduce the temperature of the gas phase product to 83°C. Among them, the low-temperature hot water heat exchanger 4 uses the gas phase product as a heat source and water as a cold source. The gas phase exchanged 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 40°C by the feed cooler 5 for a second separation to obtain a rich gas phase and a condensed oil phase;

[0066] The rich gas phase, the supplementary absorbent and the liquid phase product are introduced into the absorption tower 7 for absorption treatment to obtain an absorption gas phase and an absorption oil phase; wherein the absorption treatment conditions include: the tower bottom temperature is 48°C, the tower top pressure is 2.4MPa(G), and the theoretical number of plates of the absorption tower is 10; the absorption gas phase is frozen to 10°C by the freezing separation device 8 and then separated to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is treated by the purification unit 9, and the obtained hydrogen product (pure The desorption process comprises the following steps: feeding the desorption gas into a hydrogen pipeline network with a concentration of 99.9 mol %), discharging the obtained PSA desorption gas; mixing the condensed oil with the condensed oil phase and then entering a desorption tower 11 for desorption treatment to obtain desorption gas and desorption oil phase; wherein the desorption treatment conditions include: a bottom temperature of 120° C. and a top pressure of 1.05 MPa(G); pressurizing the desorption gas to 2.5 MPa(G) by a desorption gas booster 12 and then mixing the desorption gas with the gas phase product and the absorption oil phase for the second separation;

[0067] The desorbed oil phase is heat exchanged with the C6+ component at the bottom of the stabilization tower to 145°C and then enters the stabilization tower 15 for treatment to obtain a light component at the top of the stabilization tower and a C6+ component at the bottom of the tower; the C6+ component at the bottom of the tower is first heat exchanged with the desorbed oil phase, and then successively passes through the second reboiler 14, the third reboiler 23 and the first reboiler 13 for heat exchange and cooling to 40°C, and is 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 The light components at the top of the stabilizing tower are fed into the depropanizer 20 for fractionation to obtain the propane product and the C4-C5 component product; wherein the operating conditions of the stabilizing tower 15 include: a top pressure of 1.2 MPa (G), a top temperature of 40°C, and a bottom temperature of 235°C; the operating conditions of the depropanizer 20 include: a top pressure of 1.4 MPa (G), a top temperature of 40°C, and a bottom temperature of 93°C.

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

[0069] Comparative Example 1

[0070] use Figure 2 The system is subjected to absorption stabilization process;

[0071] The method of the 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 the desorption gas booster 12 is not provided. 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 and 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 24 and sent to the PSA system for hydrogen purification and then fed into 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 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: Cooling the upstream product and performing a first separation to obtain a gas phase product and a liquid phase product; The gas phase product is compressed and cooled before a second separation is performed to obtain a gas-rich phase and a condensed oil phase; the gas-rich phase, the supplementary 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 tower top pressure for the absorption treatment is 1.7 to 2.8 MPa (G); The absorbed gas phase is subjected to freezing separation in a freezing separation device (8) to obtain hydrogen-rich dry gas and condensed oil; the hydrogen-rich dry gas is subjected to treatment in a purification unit (9) to obtain hydrogen product and PSA desorption gas; The condensed oil is mixed with the condensed oil phase and then enters a desorption tower (11) for desorption treatment to obtain desorbed gas and desorbed oil phase; wherein the tower top pressure of the desorption treatment is 0.6-1.5 MPa(G); the desorbed gas is pressurized to 1.7-2.8 MPa(G) and then mixed with the gas phase product and the absorbed oil phase for the second separation; the desorbed oil phase is sequentially processed through a stabilization tower (15) and a depropanizer (20) 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 method further comprises allowing the liquid phase product and the supplementary absorbent to enter from the upper part of the absorption tower (7) and to countercurrently contact with the rich gas phase entering from the bottom of the absorption tower (7).

3. The method according to claim 1, characterized in that: The absorption treatment conditions include: the tower bottom temperature is 12 to 60°C, the tower top pressure is 2.0 to 2.7 MPa (G), and the theoretical plate number of the absorption tower (7) 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 (11) is 5-35.

4. The method according to claim 1, characterized in that: The ratio of the operating pressures of the absorption tower (7) and the desorption tower (11) is (1.1-3.1):

1.

5. The method according to claim 1, characterized in that The cold source used by the freezing separation device (8) is chilled water; the temperature of the freezing separation is 4-20°C.

6. The method according to claim 1, characterized in that Before the second separation is performed, the gas phase obtained by sequentially treating the gas phase product with a rich gas compressor (3) and a low-temperature hot water heat exchanger (4) is mixed with the absorbed oil phase and the desorbed gas after pressurization to obtain a mixed feed; and the mixed feed is cooled by a feed cooler (5).

7. The method according to claim 1, characterized in that The method further comprises subjecting the desorbed oil phase to treatment in a stabilization tower (15) to obtain a light component at the top of the stabilization 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; allowing the second C6+ component to enter the absorption tower (7) as the supplementary absorbent; The light component at the top of the stabilizing tower is fed into the depropanizer (20) for fractionation treatment to obtain the propane product and the C4-C5 component product.

8. 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 (15).

9. The method according to claim 7, characterized in that: The operating conditions of the stabilization tower (15) 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 (20) 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 (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 tower 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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