CN219409635U - Recovery system for refinery dry gas - Google Patents

Abstract

The utility model provides a recovery system for refinery dry gas, which comprises a deethanizer, an ethane tower, a low-temperature washing tower and a pressure swing adsorption device, wherein the deethanizer is used for carrying out first rectification separation on the refinery dry gas so as to obtain first liquid and first gas; the ethane tower is used for carrying out secondary rectification separation on the first gas so as to obtain ethane and second gas; the low-temperature washing tower is used for washing the second gas at a low temperature to obtain second liquid and hydrogen-rich gas; the pressure swing adsorption device is used for purifying the hydrogen-rich gas to obtain a pure hydrogen product. According to the method, the refinery dry gas is subjected to repeated rectification separation, low-temperature washing and purification treatment, so that on one hand, the recovery rate and recovery purity of hydrogen recovered from the refinery dry gas are greatly improved; on the other hand, the method can separate and purify the effective components in the refinery dry gas, is used as chemical raw materials or products, and fully utilizes the effective components, thereby increasing the economic benefit of the refinery dry gas.

Description

Recovery system for refinery dry gas

Technical Field

The utility model relates to the technical field of low-temperature separation of refinery dry gas, in particular to a recovery system for the refinery dry gas.

Background

The refinery dry gas refers to non-condensed gas (also called distilled gas) generated and recovered in the refinery process, and the main components of the non-condensed gas are hydrogen, ethylene, propylene, methane, ethane, propane, butane and the like, and the refinery dry gas mainly comes from the secondary processing process of crude oil, such as heavy oil catalytic cracking, thermal cracking, delayed coking and the like. Although the light hydrocarbon and the hydrogen in the refinery dry gas have higher utilization value, the light hydrocarbon and the hydrogen are usually sent into a gas pipe network to be used as fuel gas, and some of the fuel gas is even put into a torch to be burnt, so that the great waste of resources is caused.

Along with continuous production of a refinery hydrogenation device, the demand of the refinery for hydrogen is increased increasingly, and if high-added-value hydrogen in refinery dry gas is recovered, the hydrogen product can fill the defects and shortage of refinery oil upgrading and structure optimizing processes. In addition, other effective components in the hydrogen-rich tail gas are utilized in quality division, so that considerable economic benefits can be brought to enterprises.

The hydrogen energy source is used as a novel energy source and has the advantages of high heat value, green, no pollution and the like. The traditional recovery method mainly adopts a pressure swing adsorption technology and a membrane separation technology. However, the recovery rate and purity of hydrogen in the conventional recovery method are low.

Disclosure of Invention

Based on this, it is necessary to provide a recovery system for refinery dry gas, aiming at the problem of low recovery rate and purity of hydrogen in the conventional recovery method.

The technical scheme is as follows:

in one aspect, a recovery system for refinery dry gas is provided, the recovery system comprises a deethanizer, an ethane tower, a low-temperature washing tower and a pressure swing adsorption device, wherein the deethanizer, the ethane tower, the low-temperature washing tower and the pressure swing adsorption device are correspondingly communicated in sequence; the deethanizer is used for carrying out primary rectification separation on refinery dry gas to obtain first liquid and first gas; the ethane tower is used for carrying out secondary rectification separation on the first gas so as to obtain ethane and second gas; the low-temperature washing tower is used for washing the second gas at a low temperature to obtain second liquid and hydrogen-rich gas; the pressure swing adsorption device is used for purifying the hydrogen-rich gas to obtain a pure hydrogen product.

When the recovery system for the refinery dry gas in the embodiment is used, firstly, the refinery dry gas is subjected to first rectification separation by utilizing the deethanizer so as to obtain first liquid and first gas; then, carrying out second rectification separation on the first gas by utilizing an ethane tower to obtain ethane and second gas; then, washing the second gas at a low temperature through a low-temperature washing tower to obtain second liquid and hydrogen-rich gas; and finally, purifying the hydrogen-rich gas by a pressure swing adsorption device to obtain a pure hydrogen product. Compared with the traditional recovery method, the recovery system of the application utilizes the difference of the boiling points of all the component gases in the refinery dry gas, and the recovery rate and the recovery purity of the hydrogen recovered from the refinery dry gas are greatly improved by carrying out rectification separation, low-temperature washing and purification treatment on the refinery dry gas for a plurality of times so as to gradually remove other components except the hydrogen in the refinery dry gas. In addition, the refinery dry gas is subjected to multiple rectification separation, low-temperature washing and purification treatment, so that the effective components in the refinery dry gas can be purified and utilized in a quality-dividing way, and the effective components are used as chemical raw materials or products and fully utilized, thereby increasing the economic benefit of the refinery dry gas.

The technical scheme is further described as follows:

in one embodiment, the recovery system further comprises a pressurizing part, a deacidification device and a dehydration device, wherein the pressurizing part, the deacidification device and the dehydration device are correspondingly communicated in sequence, the dehydration device is correspondingly communicated with the deethanizer, and the pressurizing part is used for pressurizing the refinery dry gas; the deacidification device is used for carrying out impurity removal treatment on the refinery dry gas so as to remove acidic impurities in the refinery dry gas; the dehydration device is used for carrying out dehydration treatment on the refinery dry gas so as to obtain purified dry gas.

In one embodiment, the recovery system further comprises a first heat exchange member, one end of the first heat exchange member is correspondingly communicated with the dehydration device, and the other end of the first heat exchange member is correspondingly communicated with the deethanizer.

In one embodiment, the first heat exchange member is provided with a first heat exchange channel for conveying a first heat exchange medium, the ethane tower is provided with a second heat exchange channel for conveying the first heat exchange medium, and the first heat exchange channel is correspondingly communicated with the second heat exchange channel.

In one embodiment, the recovery system further includes a liquefied petroleum gas tower, wherein the liquefied petroleum gas tower is correspondingly communicated with the deethanizer, and the liquefied petroleum gas tower is used for performing third rectification separation on the first liquid to obtain light oil and liquefied petroleum gas.

In one embodiment, the recovery system further comprises a second heat exchange member, a first separator and a first condensate pump, wherein the first separator is provided with a first air inlet end, a first air outlet end and a first liquid outlet end, one end of the second heat exchange member is correspondingly communicated with the deethanizer, the other end of the second heat exchange member is correspondingly communicated with the first air inlet end, the first air outlet end is correspondingly communicated with the ethane tower, the first liquid outlet end is correspondingly communicated with the first condensate pump, and the first condensate pump is correspondingly communicated with the deethanizer.

In one embodiment, the recovery system further comprises a third heat exchange member, a second separator and a second condensate pump, wherein the second separator is provided with a second air inlet end, a second air outlet end and a second liquid outlet end, one end of the third heat exchange member is correspondingly communicated with the ethane tower, the other end of the third heat exchange member is correspondingly communicated with the second air inlet end, the second air outlet end is correspondingly communicated with the low-temperature washing tower, the second liquid outlet end is correspondingly communicated with the second condensate pump, and the second condensate pump is correspondingly communicated with the ethane tower.

In one embodiment, the recovery system further includes a fourth heat exchange member, a fifth heat exchange member, a nitrogen circulation refrigeration device and a mixed circulation refrigeration device, one end of the fourth heat exchange member is correspondingly communicated with the second air outlet end, the other end of the fourth heat exchange member is correspondingly communicated with one end of the fifth heat exchange member, the other end of the fifth heat exchange member is correspondingly communicated with the low-temperature washing tower, the mixed circulation refrigeration device is correspondingly communicated with the second heat exchange member, the third heat exchange member and the fourth heat exchange member, and the nitrogen circulation refrigeration device is correspondingly communicated with the second heat exchange member, the third heat exchange member, the fourth heat exchange member and the fifth heat exchange member.

In one embodiment, the recovery system further comprises a methane column correspondingly communicated with the low-temperature scrubber, and the low-temperature scrubber is used for performing fourth rectification separation on the second liquid to obtain methane and fuel gas.

In one embodiment, the recovery system further comprises a cold box, and the ethane column and the cryogenic scrubber are both disposed within the cold box.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model.

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a recovery system for refinery dry gas according to an embodiment.

Reference numerals illustrate:

10. a recovery system; 101. a deethanizer; 102. an ethane column; 103. a low temperature scrubber; 104. a pressure swing adsorption apparatus; 105. a pressurizing member; 106. a deacidification device; 107. a dehydration device; 108. a first heat exchange member; 109. a liquefied petroleum gas column; 110. a second heat exchange member; 111. a first separator; 112. a first condensate pump; 113. a third heat exchange member; 114. a second separator; 115. a second condensate pump; 116. a fourth heat exchange member; 117. a fifth heat exchange member; 118. a nitrogen cycle refrigeration device; 119. a mixed cycle refrigeration device; 120. and (3) a methane tower.

Detailed Description

In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model. The present utility model may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the utility model, whereby the utility model is not limited to the specific embodiments disclosed below.

As shown in fig. 1, in one embodiment, there is provided a recovery system 10 for refinery dry gas, the recovery system 10 comprising a deethanizer 101, an ethane tower 102, a cryogenic scrubber 103 and a pressure swing adsorption unit 104, the deethanizer 101, ethane tower 102, cryogenic scrubber 103 and pressure swing adsorption unit 104 being in corresponding communication in sequence; the deethanizer 101 is configured to perform a first rectification separation on the refinery dry gas to obtain a first liquid and a first gas; the ethane tower 102 is used for carrying out second rectification separation on the first gas to obtain ethane and second gas; the low-temperature washing tower 103 is used for washing the second gas at a low temperature to obtain a second liquid and hydrogen-rich gas; pressure swing adsorption unit 104 is used to purify hydrogen-rich gas to obtain a pure hydrogen product.

In use of the recovery system 10 of the above embodiment, first, the first rectification separation is performed on the refinery dry gas by using the deethanizer 101 to obtain a first liquid and a first gas; then, the first gas is subjected to secondary rectification separation by utilizing the ethane tower 102 so as to obtain ethane and second gas; then, the second gas is subjected to low-temperature washing through a low-temperature washing tower 103 to obtain second liquid and hydrogen-rich gas; finally, the hydrogen-rich gas is purified by the pressure swing adsorption apparatus 104 to obtain a pure hydrogen product. Compared with the traditional recovery method, the recovery system 10 of the application utilizes the difference of the boiling points of all the component gases in the refinery dry gas, and performs repeated rectification separation, low-temperature washing and purification treatment on the refinery dry gas so as to gradually remove other components except hydrogen in the refinery dry gas, thereby greatly improving the recovery rate and recovery purity of the hydrogen recovered from the refinery dry gas. In addition, the refinery dry gas is subjected to multiple rectification separation, low-temperature washing and purification treatment, so that the effective components in the refinery dry gas can be purified and utilized in a quality-dividing way, and the effective components are used as chemical raw materials or products and fully utilized, thereby increasing the economic benefit of the refinery dry gas.

The first liquid refers to propylene and heavier components after condensing and liquefying, and the first gas refers to ethane and lighter components (e.g., ethylene and methane).

The second gas is the remaining gas after the ethane is separated from the first gas, and includes methane, hydrogen, carbon monoxide, nitrogen, and the like. The second liquid is formed by condensing and liquefying a gas other than hydrogen in the second gas.

In the present application, the recovery purity of ethane can be up to 95% or more, and the recovery rate of ethane can be up to 95% or more. The recovery purity of hydrogen in the hydrogen-rich gas in this application is about 80%. The recovery rate of the pure hydrogen product in the method can reach more than 98 percent, and the recovery purity of the pure hydrogen product can reach more than 99.9 percent.

In particular to this embodiment, the temperature in the deethanizer 101 tends to decrease from bottom to top, the temperature at the bottom of the deethanizer 101 is 84 ℃, the first liquid is at the bottom of the deethanizer 101, the temperature at the top of the deethanizer 101 is-33 ℃, and the first gas is at the top of the deethanizer 101. The temperature in the ethane column 102 tends to decrease from bottom to top, the temperature at the bottom of the ethane column 102 is 4 ℃, the ethane is at the bottom of the ethane column 102, the temperature at the top of the ethane column 102 is-118 ℃, and the second gas is at the top of the ethane column 102. The temperature in the low temperature scrubber 103 tends to decrease from bottom to top, the temperature at the bottom of the low temperature scrubber 103 is-175 ℃, the second liquid is at the bottom of the low temperature scrubber 103, the temperature at the top of the low temperature scrubber 103 is-180 ℃, and the hydrogen rich gas is at the top of the low temperature scrubber 103.

As shown in fig. 1, further, the recovery system 10 further includes a pressurizing element 105, a deacidification device 106 and a dehydration device 107, where the pressurizing element 105, the deacidification device 106 and the dehydration device 107 are correspondingly communicated in sequence, the dehydration device 107 is correspondingly communicated with the deethanizer 101, and the pressurizing element 105 is used for pressurizing refinery dry gas; the deacidification device 106 is used for carrying out impurity removal treatment on the refinery dry gas so as to remove acidic impurities in the refinery dry gas; the dehydration system is used for carrying out dehydration treatment on the refinery dry gas so as to obtain purified dry gas. In this manner, the pressurizing member 105 can pressurize the refinery dry gas so that the refinery dry gas can flow along the preset path, improving the reliability of the recovery system 10. In addition, the deacidification device 106 can remove carbon dioxide, hydrogen sulfide and other acidic impurities in the refinery dry gas, and the dehydration device 107 can remove water in the refinery dry gas, so that the purity of products such as hydrogen recovered by the recovery system 10 is improved.

It is contemplated that the booster 105 may be a booster pump, a compressor, or other booster structure. The deacidification device 106 may be a spray tower or a deacidification device capable of removing acid gases such as carbon monoxide and hydrogen sulfide. The dehydration means 107 may be a distillation column, a gas dehydration device, or an existing device for removing moisture from a gas.

As shown in fig. 1, the recovery system 10 optionally further includes a first heat exchange member 108, one end of the first heat exchange member 108 is correspondingly in communication with the dehydration device 107, and the other end of the first heat exchange member 108 is correspondingly in communication with the deethanizer 101. In this way, the first heat exchange member 108 can perform the first heat exchange on the purified dry gas, reduce the temperature of the purified gas to be slightly higher than the boiling point temperature of the first liquid, ensure that the deethanizer 101 can perform the first rectification separation on the purified dry gas to obtain the first liquid and the first gas, and improve the reliability of the recovery system 10

It should be noted that the first heat exchange member 108 may be a heat exchanger, a reboiler, or other heat exchange structure. In particular, in this embodiment, the first heat exchange member 108 is configured as a first reboiler capable of cooling the purge gas at 40 ℃ to 14 ℃.

As shown in fig. 1, optionally, the first heat exchange member 108 is provided with a first heat exchange channel for conveying the first heat exchange medium, and the ethane tower 102 is provided with a second heat exchange channel for conveying the first heat exchange medium, and the first heat exchange channel is correspondingly communicated with the second heat exchange channel. In this way, the first heat exchange medium after heat exchange with the purified gas in the first heat exchange member 108 can flow into the ethane tower 102, so that the first heat exchange medium can exchange heat with the second gas in the ethane tower 102, and further, the heat required by the ethane tower 102 can be derived from the heat exchange of the purified gas, an external heat source is not required, the comprehensive utilization of energy can be effectively realized, and the recovery cost of the recovery system 10 is reduced.

As shown in fig. 1, in one embodiment, the recovery system 10 further includes a liquefied petroleum gas tower 109, where the liquefied petroleum gas tower 109 is correspondingly in communication with the deethanizer 101, and the liquefied petroleum gas tower 109 is configured to perform a third rectifying separation on the first liquid to obtain light oil and liquefied petroleum gas. In this way, the liquefied petroleum gas tower 109 can separate the light oil in the first liquid from the liquefied petroleum gas, so that the light oil and the liquefied petroleum gas in the refinery dry gas are prevented from being wasted, and the economic benefit of the refinery dry gas is improved.

In particular, in the present embodiment, the temperature in the liquefied petroleum gas column 109 tends to decrease from bottom to top, the temperature at the bottom of the liquefied petroleum gas column 109 is 144 ℃, the light oil is located at the bottom of the liquefied petroleum gas column 109, the temperature at the top of the liquefied petroleum gas column 109 is 40 ℃ to 50 ℃, and the liquefied petroleum gas is located at the top of the liquefied petroleum gas column 109.

Referring to fig. 1, in one embodiment, the recovery system 10 further includes a second heat exchange member 110, a first separator 111, and a first condensate pump 112, where the first separator 111 is provided with a first air inlet end, a first air outlet end, and a first liquid outlet end, one end of the second heat exchange member 110 is correspondingly connected to the deethanizer 101, the other end of the second heat exchange member 110 is correspondingly connected to the first air inlet end, the first air outlet end is correspondingly connected to the ethane tower 102, the first liquid outlet end is correspondingly connected to the first condensate pump 112, and the first condensate pump 112 is correspondingly connected to the deethanizer 101. In this way, the second heat exchange member 110 can exchange heat with the first gas, and the first separator 111 can separate the first liquid in the first gas, so that the purity of the product such as hydrogen and ethane recovered by the recovery system 10 is improved. In addition, the separated first liquid can be conveyed back to the deethanizer 101 through the first condensate pump 112, thereby avoiding the waste of the first liquid and improving the recovery rate of the light oil recovered by the recovery system 10.

It should be noted that the second heat exchange member 110 may be a heat exchanger, a reboiler, or other heat exchange structures. The heat exchange temperature of the second heat exchange member 110 can be flexibly adjusted according to the actual use requirement, and only the first liquid in the first gas can be liquefied and separated. In particular in this embodiment, the second heat exchange member 110 is provided as a first heat exchanger capable of reducing the first gas from-33 ℃ to-65 ℃.

As shown in fig. 1, further, the recovery system 10 further includes a third heat exchange member 113, a second separator 114 and a second condensate pump 115, where the second separator 114 is provided with a second air inlet end, a second air outlet end and a second liquid outlet end, one end of the third heat exchange member 113 is correspondingly communicated with the ethane tower 102, the other end of the third heat exchange member 113 is correspondingly communicated with the second air inlet end, the second air outlet end is correspondingly communicated with the low-temperature washing tower 103, the second liquid outlet end is correspondingly communicated with the second condensate pump 115, and the second condensate pump 115 is correspondingly communicated with the ethane tower 102. In this way, the third heat exchange member 113 can exchange heat with the second gas, and the second separator 114 can separate the ethane from the second gas, so that the purity of the product such as hydrogen and ethane recovered by the recovery system 10 is improved. In addition, the separated ethane can be fed back to the ethane column 102 through the second condensate pump 115, avoiding the waste of ethane and improving the recovery rate of ethane recovered by the recovery system 10.

It should be noted that the third heat exchange member 113 may be a heat exchanger, a reboiler, or other heat exchange structures.

In other embodiments, the recovery system 10 further includes a second reboiler, one end of which is in communication with the third heat exchanger, and the other end of which is in communication with the second separator 114. In this way, the second reboiler can cool the first gas again, so that the ethane tower 102 can perform second rectification separation on the first gas, so as to obtain ethane and second gas, and reliability of the recovery system 10 is improved.

It should be noted that, the heat exchange temperature of the second heat exchange member 110 and the heat exchange temperature of the second reboiler may be flexibly adjusted according to the actual use requirement, and only the ethane in the second gas may be liquefied and separated. In particular to this embodiment, the second heat exchange member 110 is configured as a first heat exchanger capable of reducing the first gas from-74 ℃ to-94 ℃ and a second reboiler capable of reducing the first gas from-94 ℃ to-118 ℃.

As shown in fig. 1, optionally, the recovery system 10 further includes a fourth heat exchange member 116, a fifth heat exchange member 117, a nitrogen circulation refrigeration device 118 and a mixed circulation refrigeration device 119, where one end of the fourth heat exchange member 116 is correspondingly communicated with the second outlet end, the other end of the fourth heat exchange member 116 is correspondingly communicated with one end of the fifth heat exchange member 117, the other end of the fifth heat exchange member 117 is correspondingly communicated with the low-temperature scrubber 103, the mixed circulation refrigeration device 119 is correspondingly communicated with the second heat exchange member 110, the third heat exchange member 113 and the fourth heat exchange member 116, and the nitrogen circulation refrigeration device 118 is correspondingly communicated with the second heat exchange member 110, the third heat exchange member 113, the fourth heat exchange member 116 and the fifth heat exchange member 117. In this way, the fourth heat exchange member 116 and the fifth heat exchange member 117 can cooperate to reduce the temperature of the second gas to a temperature slightly higher than the boiling point temperature of the second liquid, so as to ensure that the low-temperature scrubber 103 can perform low-temperature scrubbing on the second gas to obtain the second liquid and the hydrogen-rich gas, thereby improving the reliability of the recovery system 10. In addition, the nitrogen cycle refrigeration unit 118 can reduce the temperature of the second gas to a lower range, thereby ensuring that the cryogenic scrubber 103 can deeply remove low boiling components such as carbon monoxide, methane, nitrogen and the like, and improving the purity of the hydrogen recovered by the recovery system 10.

It should be noted that, the fourth heat exchange element 116 and the fifth heat exchange element 117 may be heat exchangers, reboilers, subcoolers, or other heat exchange structures. In particular, in this embodiment, the fourth heat exchanging element 116 is provided with a third heat exchanger, the fifth heat exchanging element 117 is provided with a subcooler, the third heat exchanger can reduce the temperature of the second gas from-118 ℃ to-165 ℃, and the subcooler can reduce the temperature of the second gas from-165 ℃ to-171 ℃.

It should be noted that the refrigerant in the mixed circulation refrigeration device 119 may be a multicomponent mixture (such as methane, nitrogen, propane, ethylene, isopentane, etc.), and the components and compositions of the refrigerant may be flexible and changeable according to the composition of different refinery dry gases.

The tail gas of the pressure swing adsorption device 104 is mainly nitrogen, and may enter the nitrogen circulation refrigeration device 118 for cyclic utilization, and the deficient portion is replenished from the outside. The nitrogen cycle refrigeration unit 118 may reduce the temperature of the second gas by-180 ℃.

In one embodiment, as shown in FIG. 1, the recovery system 10 further includes a methane column 120, the methane column 120 being in corresponding communication with a cryogenic scrubber 103, the cryogenic scrubber 103 being configured to perform a fourth rectification separation of the second liquid to obtain methane and fuel gas. Thus, the methane tower 120 can separate methane from fuel gas in the second liquid, so that waste of methane and fuel gas in the refinery dry gas is avoided, and economic benefit of the refinery dry gas is improved.

In the embodiment, the recovery purity of methane can reach more than 93%, and the recovery rate of methane can reach more than 99%. The fuel gas can be used as device fuel gas or returned to a refinery fuel system for utilization after being subjected to rewarming sequentially through the cooler, the third heat exchanger, the second heat exchanger and the first heat exchanger.

In other embodiments, the hydrogen-rich gas in the low temperature scrubber 103 is re-warmed by the cooler, the third heat exchanger, the second heat exchanger, and the first heat exchanger in sequence and then delivered to the pressure swing adsorption apparatus 104. In this way, the pressure swing adsorption apparatus 104 is ensured to be able to extract high purity hydrogen.

In particular, in this embodiment, the temperature in the methane column 120 tends to decrease from bottom to top, the temperature at the bottom of the methane column 120 is-130 ℃, methane is at the bottom of the methane column 120, the temperature at the top of the methane column 120 is-172 ℃, and the fuel gas is at the top of the methane column 120.

Further, the second reboiler is provided with a third heat exchange channel for conveying the second heat exchange medium, and the methane tower 120 is provided with a fourth heat exchange channel for conveying the second heat exchange medium, and the third heat exchange channel is correspondingly communicated with the fourth heat exchange channel. In this way, the second heat exchange medium after heat exchange with the first gas in the second reboiler can flow into the methane tower 120 and exchange heat with the second liquid in the methane tower 120, so that the heat required by the methane tower 120 can be derived from the heat exchange of the first gas, an external heat source is not needed, the comprehensive utilization of energy can be effectively realized, and the recovery cost of the recovery system 10 is reduced.

Optionally, the recovery system 10 further comprises a cold box, in which the ethane column 102, the cryogenic scrubber 103 and the methane column 120 are disposed. Thus, the cold box can effectively ensure the cold insulation effect of the ethane tower 102, the low-temperature washing tower 103 and the methane tower 120, reduce the loss of cold energy and improve the reliability of the recovery system 10.

In other embodiments, the first separator 111, the second separator 114, and the methane column 120 may be disposed within a cold box. The reliability of the recovery system 10 is improved.

In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., these terms refer to the orientation or positional relationship based on the drawings, which are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In this application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either in direct contact or in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

It will be further understood that when interpreting the connection or positional relationship of elements, although not explicitly described, the connection and positional relationship are to be interpreted as including the range of errors that should be within an acceptable range of deviations from the particular values as determined by those skilled in the art. For example, "about," "approximately," or "substantially" may mean within one or more standard deviations, and is not limited herein.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.

Claims (10)

1. The recovery system for the refinery dry gas is characterized by comprising a deethanizer, an ethane tower, a low-temperature washing tower and a pressure swing adsorption device, wherein the deethanizer, the ethane tower, the low-temperature washing tower and the pressure swing adsorption device are correspondingly communicated in sequence; the deethanizer is used for carrying out primary rectification separation on refinery dry gas to obtain first liquid and first gas; the ethane tower is used for carrying out secondary rectification separation on the first gas so as to obtain ethane and second gas; the low-temperature washing tower is used for washing the second gas at a low temperature to obtain second liquid and hydrogen-rich gas; the pressure swing adsorption device is used for purifying the hydrogen-rich gas to obtain a pure hydrogen product.

2. The recovery system for refinery dry gas of claim 1, further comprising a pressurizing element, a deacidifying device and a dewatering device, wherein the pressurizing element, the deacidifying device and the dewatering device are correspondingly communicated in sequence, the dewatering device is correspondingly communicated with the deethanizer, and the pressurizing element is used for pressurizing the refinery dry gas; the deacidification device is used for carrying out impurity removal treatment on the refinery dry gas so as to remove acidic impurities in the refinery dry gas; the dehydration device is used for carrying out dehydration treatment on the refinery dry gas so as to obtain purified dry gas.

3. The recovery system for refinery dry gas of claim 2, further comprising a first heat exchange member having one end in communication with the dehydration device and another end in communication with the deethanizer.

4. A recovery system for refinery dry gas of claim 3, wherein said first heat exchange member is provided with a first heat exchange channel for transporting a first heat exchange medium, said ethane tower is provided with a second heat exchange channel for transporting said first heat exchange medium, said first heat exchange channel being in corresponding communication with said second heat exchange channel.

5. The recovery system for refinery dry gas of claim 1, further comprising a liquefied petroleum gas tower in corresponding communication with said deethanizer, said liquefied petroleum gas tower for performing a third rectifying separation of said first liquid to obtain light oil and liquefied petroleum gas.

6. The recovery system for refinery dry gas of claim 1, further comprising a second heat exchange member, a first separator and a first condensate pump, wherein the first separator is provided with a first air inlet end, a first air outlet end and a first liquid outlet end, one end of the second heat exchange member is correspondingly communicated with the deethanizer, the other end of the second heat exchange member is correspondingly communicated with the first air inlet end, the first air outlet end is correspondingly communicated with the ethane tower, the first liquid outlet end is correspondingly communicated with the first condensate pump, and the first condensate pump is correspondingly communicated with the deethanizer.

7. The recovery system for refinery dry gas of claim 6, further comprising a third heat exchange member, a second separator and a second condensate pump, wherein the second separator is provided with a second air inlet end, a second air outlet end and a second liquid outlet end, one end of the third heat exchange member is correspondingly communicated with the ethane tower, the other end of the third heat exchange member is correspondingly communicated with the second air inlet end, the second air outlet end is correspondingly communicated with the low-temperature washing tower, the second liquid outlet end is correspondingly communicated with the second condensate pump, and the second condensate pump is correspondingly communicated with the ethane tower.

8. The recovery system for refinery dry gas of claim 7, further comprising a fourth heat exchange member, a fifth heat exchange member, a nitrogen circulation refrigeration device and a mixed circulation refrigeration device, wherein one end of the fourth heat exchange member is correspondingly communicated with the second outlet end, the other end of the fourth heat exchange member is correspondingly communicated with one end of the fifth heat exchange member, the other end of the fifth heat exchange member is correspondingly communicated with the cryogenic washing tower, the mixed circulation refrigeration device is correspondingly communicated with the second heat exchange member, the third heat exchange member and the fourth heat exchange member, and the nitrogen circulation refrigeration device is correspondingly communicated with the second heat exchange member, the third heat exchange member, the fourth heat exchange member and the fifth heat exchange member.

9. The recovery system for refinery dry gas of any one of claims 1-8, further comprising a methane column in corresponding communication with the cryogenic scrubber for fourth rectification separation of the second liquid to obtain methane and fuel gas.

10. The recovery system for refinery dry gas of any one of claims 1-8, further comprising a cold box in which both the ethane column and the cryogenic scrubber are disposed.