Hydrogenated product separation system

Abstract

The hydrogenation product separation system comprises a separation device, a steam stripping device and a fractionating tower which are sequentially connected along the reaction effluent direction, the separation device is used for treating the reaction effluent to obtain hot low-pressure oil and cold low-pressure oil; the steam stripping device comprises a first steam stripping tower and a second steam stripping tower, cold low-separation oil is input into an inlet of the first steam stripping tower, hot low-separation oil is input into an inlet of the second steam stripping tower, a top gas outlet of the second steam stripping tower is communicated to the first steam stripping tower, and a bottom oil outlet of the first steam stripping tower is communicated to a first feeding hole in the upper half part of the fractionating tower; a bottom oil outlet of the second stripping tower is communicated with a feeding heating furnace and then is connected to a second feeding hole in the lower half part of the fractionating tower; and the fractionating tower is used for carrying out light and heavy oil product cutting on materials input from the first feeding hole and the second feeding hole. The double stripping towers are arranged, the cold low-pressure oil and the hot low-pressure oil are subjected to stripping respectively, feeding is performed on different trays of the fractionating tower subsequently, repeated vaporization of part of oil products is avoided, and meanwhile, the load of a feeding heating furnace of the fractionating tower is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of oil product hydrocracking, in particular to a hydrogenation product separation system. Background Art

[0002] In the hydrocracking unit, after the oil product is mixed with hydrogen, it undergoes a series of heat exchanges and enters the reactor to react with the catalyst. The reaction effluent is usually treated with a hot high-fraction process, that is, the reaction product is sent to a hot high-pressure separator after heat exchange, and the oil product at the bottom of the hot high-pressure separator is depressurized and enters a hot low-pressure separator for further separation. The hot low-fraction oil at the bottom of the hot low-pressure separator is to be sent to the subsequent distillation part; the hot high-fraction gas at the top of the hot high-pressure separator contains oil and gas vaporized at high temperature and unreacted hydrogen, and contains by-products such as H2S and NH3 and other impurities. It is necessary to remove impurities through water injection, cooling and other operations, and then enrich the oil in it, and combine it with the hot low-fraction gas after cooling at the top of the hot low-pressure separator as cold low-fraction oil and send it to the subsequent distillation part (this part of the oil product still contains some H2S, which needs to be removed at the top of the stripping tower after stripping).

[0003] The traditional treatment method of the fractionation part of the oil hydrocracking unit is a double-tower stripping mode of a stripper + fractionator. The hot low-fraction oil and the cold low-fraction oil obtained by the stripper from the reaction effluent are used as the feed of the stripper at the same time. Low-pressure steam is introduced into the bottom of the stripper to strip the oil products to complete the separation of H2S, unstable naphtha and the bottom oil of the stripper: the light hydrocarbons with hydrogen sulfide are removed at the top of the stripper; the bottom oil of the stripper enters the main fractionator after heat exchange. After gas-liquid mass transfer separation, the top of the main fractionator produces stable light naphtha, and the bottom of the main fractionator produces hydrogenated tail oil.

[0004] However, in the fractionation process of this treatment method, the hot low fraction oil and the cold low fraction oil enter the stripping tower at the same time. The two oil products have different temperatures and components: the cold low fraction oil is lighter, and its main components are naphtha and diesel; the hot low fraction oil is heavier, and its main components are diesel and hydrogenated tail oil. After being stripped by the stripping tower, the bottom oil phase is sent to the fractionation tower as feed, and the fractionation tower feed heating furnace needs to provide heat for it to ensure smooth cutting of the fractionation tower. The heating process of the oil products will inevitably cause the light diesel in the fractionation tower feed oil to be vaporized twice, and the heating furnace load is high, and the energy consumption needs to be improved urgently. Utility Model Content

[0005] In view of the problem of repeated vaporization of oil products during the hydrocracking process, the purpose of the utility model is to provide a hydrogenation product separation system, which provides two stripping towers to strip the cold low-fraction oil and the hot low-fraction oil respectively, and then feed them to different trays of the distillation tower respectively, thereby avoiding repeated vaporization of some oil products and reducing the load of the distillation tower feed heating furnace.

[0006] In order to achieve the above object, the utility model provides

[0007] A hydrogenation product separation system, comprising

[0008] Separation device, stripping device and fractionation tower connected in sequence along the direction of reaction effluent;

[0009] The separation device processes the reaction effluent to obtain hot low-fraction oil and cold low-fraction oil;

[0010] The stripping device comprises a first stripping tower and a second stripping tower, the cold low fraction oil is input into the inlet of the first stripping tower, the hot low fraction oil is input into the inlet of the second stripping tower, the top gas outlet of the second stripping tower is connected to the first stripping tower, the bottom oil outlet of the first stripping tower is connected to the first feed inlet located in the upper half of the fractionation tower, and the bottom oil outlet of the second stripping tower is connected to the feed heating furnace and then connected to the second feed inlet located in the lower half of the fractionation tower;

[0011] The fractionation tower separates the materials input from the first feed inlet and the second feed inlet into light and heavy oil products.

[0012] In some technical schemes, a feed flash tank is connected in series on the connecting pipeline between the second stripping tower and the feed heating furnace, the liquid phase outlet at the bottom of the feed flash tank is connected to the feed heating furnace, and the gas phase outlet at the top of the feed flash tank is connected to the third feed port in the middle section of the distillation tower.

[0013] Some technical solutions further include a first heat exchange device,

[0014] The cold side of the first heat exchange device corresponds to the bottom oil outlet pipeline of the second stripping tower, and the hot side of the first heat exchange device corresponds to the feed pipeline of the reaction effluent.

[0015] In some technical solutions, the upper part of the distillation tower is connected to a naphtha output pipeline, the middle part is connected to a diesel output pipeline, and the lower part is connected to a hydrogenated oil output pipeline.

[0016] In some technical solutions, the separation device includes a hot high-separator, a cold low-separation oil separation pipeline connected to its gas phase outlet, and a hot low-separation oil separation pipeline connected to its liquid phase outlet;

[0017] The cold low oil separation pipeline is communicated with the first stripping tower; the hot low oil separation pipeline is communicated with the second stripping tower.

[0018] In some technical solutions, the separation device also includes a cold high separator and a cold low separator arranged on the cold low oil separation pipeline, the inlet of the cold high separator is connected to the gas phase outlet of the hot high separator, the liquid phase outlet of the cold high separator is connected to the cold low separator, and the liquid phase outlet of the cold low separator is connected to the first stripping tower; the gas phase outlets of the cold high separator and the cold low separator are connected to the subsequent processing section.

[0019] In some technical solutions, the separation device also includes a hot low separator arranged on the hot low oil separation pipeline, the inlet of the hot low separator is connected to the liquid phase outlet of the hot high separator, the gas phase outlet of the hot low separator is connected to the inlet of the cold low separator, and the liquid phase outlet of the hot low separator is connected to the second stripping tower.

[0020] Some technical solutions further include a second heat exchange device,

[0021] The cold side of the second heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator, and the hot side of the second heat exchange device corresponds to the feed pipeline of the reaction effluent.

[0022] Some technical solutions also include a third heat exchange device,

[0023] The hot side of the third heat exchange device corresponds to the gas phase outlet pipeline of the hot high separator, and the cold side of the third heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator or the bottom oil outlet pipeline of the second stripping tower.

[0024] In some technical solutions, the first stripping tower is provided with a tower top gas reflux pipeline, and the tower top gas reflux pipeline is sequentially connected to the tower top gas outlet of the first stripping tower, the first reflux tank and the tower top gas reflux port;

[0025] The fractionation tower is provided with a tower top oil reflux pipeline, and the tower top oil reflux pipeline is sequentially connected to the tower top oil outlet, the second reflux tank and the tower top oil reflux port of the fractionation tower.

[0026] The utility model adopts the above technical solution to have at least the following beneficial effects:

[0027] 1. The utility model provides a hydrogenation product separation system. By setting up a combination of two stripping towers + a single fractionation tower, oil products at different temperatures enter different stripping towers for stripping, and enter different trays of the fractionation tower after H2S is removed, thereby avoiding repeated vaporization of some oil products, greatly reducing the load of the feed heating furnace (reduced by about 25%), and thus reducing the energy consumption of the device;

[0028] 2. The utility model provides a hydrogenation product separation system, which flashes the bottom oil obtained after the hot low-fraction oil stripping through the feed flash tank arranged in front of the fractionation tower, and the flashed gas phase is directly used as the feed of the fractionation tower, and the oil phase is sent to the fractionation tower after being heated by the fractionation tower feed heating furnace. At this time, the feed heating furnace only heats the bottom oil of the flash tank, and the fractionation tower feed heating furnace will only gasify a small amount of diesel components, which further reduces the comprehensive energy consumption of the system, reduces the load of the feed heating furnace, and enables the fractionation tower to stably cut the oil products;

[0029] 3. The utility model provides a hydrogenation product separation system. Since the cold low-fraction oil is lighter, the main components are naphtha and diesel; the hot low-fraction oil is heavier, the main components are diesel and hydrogenation tail oil, the two oil products enter different stripping towers for stripping, and the gas-liquid mass transfer effect in each stripping tower is better than the stripping effect in a single stripping tower in traditional operation;

[0030] 4. The utility model provides a hydrogenation product separation system, which reduces the overall energy consumption of the system and further reduces the load of the feed heating furnace by utilizing the waste heat of the reaction effluent and / or the hot high-fraction gas to preheat the cold low-fraction oil and the bottom oil after the hot low-fraction oil stripping, so as to maintain a long-term stable operation of the system;

[0031] 5. The utility model provides a hydrogenation product separation system. Since the bottom oil of the first stripping tower contains naphtha, the abundant low-temperature heat in the tower can be used to vaporize the naphtha when entering the distillation tower, so as to achieve the purpose of comprehensive utilization of low-temperature heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 It is a structural schematic diagram of the hydrogenation product separation system described in an embodiment of the utility model.

[0034] The meanings of the symbols in the figure are as follows:

[0035] 11—hot high separator, 12—cold high separator, 13—cold low separator, 14—hot low separator;

[0036] 21—first stripping tower, 22—top gas reflux pipeline, 23—second stripping tower;

[0037] 31—feed flash tank, 32—feed heating furnace, 33—distillation tower, 34—tower top oil reflux pipeline. DETAILED DESCRIPTION

[0038] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0039] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0040] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0041] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0042] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0043] In one embodiment, if Figure 1, provides a hydrogenation product separation system, including a separation device, a stripping device and a fractionation tower 33 connected in sequence along the direction of the reaction effluent; the separation device processes the reaction effluent to obtain hot low-fraction oil and cold low-fraction oil; the stripping device includes a first stripping tower 21 and a second stripping tower 23, the cold low-fraction oil is input into the inlet of the first stripping tower 21, the hot low-fraction oil is input into the inlet of the second stripping tower 23, the top gas outlet of the second stripping tower 23 is connected to the first stripping tower 21, the bottom oil outlet of the first stripping tower 21 is connected to a first feed port located in the upper half of the fractionation tower 33, the bottom oil outlet of the second stripping tower 23 is connected to a feed heating furnace 32 and then connected to a second feed port located in the lower half of the fractionation tower 33; the fractionation tower 33 performs stable cutting of light and heavy oil products on the materials input into the first feed port and the second feed port.

[0044] The present application sets up a combination of two stripping towers + a single distillation tower, so that oil products at different temperatures enter different stripping towers for stripping, and enter different trays of the distillation tower 33 after H2S removal, thereby avoiding repeated vaporization of some oil products and greatly reducing the load of the feed heating furnace 32 (by about 25%), thereby reducing the energy consumption of the device.

[0045] In some preferred embodiments, a feed flash tank 31 is connected in series on the connecting pipeline between the second stripping tower 23 and the feed heating furnace 32, the liquid phase outlet at the bottom of the feed flash tank 31 is connected to the feed heating furnace 32, and the gas phase outlet at the top of the feed flash tank 31 is connected to the third feed port in the middle section of the distillation tower 33.

[0046] In this embodiment, the bottom oil obtained after hot low-fraction oil stripping is flashed again by the feed flash tank 31 arranged in front of the distillation tower, and the flashed gas phase is directly used as the distillation tower feed, and the oil phase is sent to the distillation tower 33 after being heated by the distillation tower feed heating furnace. At this time, the feed heating furnace 32 only heats the bottom oil of the flash tank, and the distillation tower feed heating furnace will only vaporize a small amount of diesel components, which further reduces the overall energy consumption of the system, reduces the load of the feed heating furnace 32, and enables the distillation tower 33 to stably cut the oil.

[0047] Preferably, the hydrogenation product separation system further comprises a first heat exchange device, the cold side of the first heat exchange device corresponds to the bottom oil outlet pipeline of the second stripping tower, and the hot side of the first heat exchange device corresponds to the feed pipeline of the reaction effluent. The residual energy of the reaction effluent is used to heat the bottom oil of the second stripping tower 23, reduce the load of the feed heating furnace 32, and reduce the energy consumption of the system.

[0048] In the above embodiment, the separation device includes a hot high oil separator 11, a cold low oil separation pipeline connected to its gas phase outlet, and a hot low oil separation pipeline connected to its liquid phase outlet; the cold low oil separation pipeline is connected to the first stripping tower 21; and the hot low oil separation pipeline is connected to the second stripping tower 23.

[0049] Specifically, the separation device also includes a cold high separator 12 and a cold low separator 13 arranged on the cold low oil separation pipeline, the inlet of the cold high separator 12 is connected to the gas phase outlet of the hot high separator 11, the liquid phase outlet of the cold high separator 12 is connected to the cold low separator 13, and the liquid phase outlet of the cold low separator 13 is connected to the first stripping tower 21; the gas phase outlets of the cold high separator 12 and the cold low separator 13 are connected to the subsequent processing section.

[0050] Specifically, the separation device also includes a hot low-oil separator 14 arranged on the hot low-oil separation pipeline, the inlet of the hot low-oil separator 14 is connected to the liquid phase outlet of the hot high-oil separator 11, the gas phase outlet of the hot low-oil separator 14 is connected to the inlet of the cold low-oil separator 13, and the liquid phase outlet of the hot low-oil separator 14 is connected to the second stripping tower 23.

[0051] In a preferred embodiment, the hydrogenation product separation system also includes a second heat exchange device, the cold side of the second heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator, and the hot side of the second heat exchange device corresponds to the feed pipeline of the reaction effluent.

[0052] In another preferred embodiment, the hydrogenation product separation system also includes a third heat exchange device, the hot side of the third heat exchange device corresponds to the gas phase outlet pipeline of the hot high separator, and the cold side of the third heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator or the bottom oil outlet pipeline of the second stripping tower 23.

[0053] In this preferred embodiment, by utilizing the waste heat of the reaction effluent and / or the hot high-fraction gas to preheat the cold low-fraction oil and the bottom oil after the hot low-fraction oil is stripped, the overall energy consumption of the system is reduced, and the load of the feed heating furnace 32 is further reduced, so that the system can maintain stable operation for a long period of time.

[0054] In the above embodiment, the first stripping tower 21 is provided with a top gas reflux pipeline 22, which is sequentially connected to the top gas outlet, the first reflux tank and the top gas reflux port of the first stripping tower 21; the distillation tower 33 is provided with a top oil reflux pipeline 34, which is sequentially connected to the top oil outlet, the second reflux tank and the top oil reflux port of the distillation tower 33.

[0055] In the above embodiment, the upper part of the fractionation tower 33 is connected to the naphtha output pipeline, the middle part is connected to the diesel output pipeline, and the lower part is connected to the hydrogenated oil output pipeline.

[0056] In order to achieve the purpose of reducing the load of the feed heating furnace of the fractionating tower, the utility model adds a stripping tower and a feed flash tank 31 on the premise of the original stripping tower + fractionating tower combined equipment. The first stripping tower 21 strips the cold low-fraction oil after being heated by the system heat exchange network, and the second stripping tower 23 directly strips the hot low-fraction oil. Then, after the bottom oil of the second stripping tower 23 is heat-exchanged and separated by gas-liquid phase in the newly added feed flash tank 31, the liquid phase (heavier oil products) enters the fractionating tower 33 after being heated by the feed heating furnace 32 of the fractionating tower 33, and the top gas of the second stripping tower 23 is sent to the first stripping tower 21. After the cold low-fraction oil and the top gas of the second stripping tower 23 are stripped and separated by the first stripping tower 21 as feed, the bottom oil of the first stripping tower 21 (lighter oil products) directly enters the upper part of the fractionating tower (above the side line extraction port) to avoid secondary gasification of light diesel oil.

[0057] In order to have a clearer understanding of the technical solution and technical effects of this application, the following process implementation principles are provided:

[0058] The reaction effluent is separated by a hot high-pressure separator, and the top hot high-fraction gas is cooled by heat recovery and a cooler and then enters a cold high-pressure separator to separate cold high-fraction oil and cold high-fraction gas; the bottom hot high-fraction oil is separated by a hot low-pressure separator to obtain hot low-fraction oil, which is then used as feed to the second stripping tower 23; the cooled hot low-fraction gas and cold high-fraction oil are mixed and then enter a cold low-pressure separator, and the top cold low-fraction gas is sent to the subsequent process section, and the cold low-fraction oil is used as feed to the first stripping tower 21;

[0059] The first stripping tower 21 is only used for stripping the cold low-fraction oil. The cold low-fraction oil has a relatively low temperature and contains H2S. After heat exchange with the hot material of the device, it enters the first stripping tower 21 as a feed. Low-pressure steam is introduced into the bottom of the tower to strip the cold low-fraction oil. Since the cold low-fraction oil still contains H2S, after gas-liquid mass transfer and separation of components with different volatilities are achieved in the first stripping tower 21, hydrogen sulfide is enriched at the top of the tower, and the top gas and the top distillate are sent to subsequent links for processing; and since the bottom oil of the first stripping tower 21 contains a large amount of diesel components, this part of the oil does not contain hydrogen sulfide, and can be directly fed into the upper part of the distillation tower as a feed for subsequent oil cutting without passing through the distillation tower feed heating furnace, thereby avoiding secondary gasification of light diesel, reducing the load of the distillation tower 33 feed heating furnace, and effectively reducing the energy consumption of the device;

[0060] The feed heating furnace of the fractionation tower 33 mainly heats the bottom of the second stripping tower to separate the heavy components through feed flash evaporation, and the diesel component in the bottom liquid of the second stripping tower heated by the heating furnace is vaporized to facilitate diesel separation in the fractionation tower 33;

[0061] The hot low fraction oil has a relatively high temperature and can be directly fed into the second stripping tower 23 as feed. After the hot low fraction oil is stripped by introducing low steam into the bottom of the tower, the separated second stripping tower top gas is fed into the first stripping tower 21 as feed; the second stripping tower bottom oil firstly extracts heat from the high heat part of the system (such as the reaction effluent), and after heat exchange and temperature increase, it first passes through the fractionation tower feed flash tank for gas-liquid phase separation, and the tank bottom liquid phase enters the fractionation tower 33 for subsequent cutting after being heated by the fractionation tower feed heating furnace, and the tank top gas phase crosses the fractionation tower feed heating furnace as feed and enters the fractionation tower 33. In this way, the fractionation tower feed heating furnace will only gasify a small amount of diesel components, thereby achieving the purpose of reducing gas consumption.

[0062] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the attached claims.

Claims

1. A hydrogenation product separation system, characterized in that: include Separation device, stripping device and fractionation tower connected in sequence along the direction of reaction effluent; The separation device processes the reaction effluent to obtain hot low-fraction oil and cold low-fraction oil; The stripping device comprises a first stripping tower and a second stripping tower, the cold low fraction oil is input into the inlet of the first stripping tower, the hot low fraction oil is input into the inlet of the second stripping tower, the top gas outlet of the second stripping tower is connected to the first stripping tower, the bottom oil outlet of the first stripping tower is connected to the first feed inlet located in the upper half of the fractionation tower, and the bottom oil outlet of the second stripping tower is connected to the feed heating furnace and then connected to the second feed inlet located in the lower half of the fractionation tower; The fractionation tower separates the materials input from the first feed inlet and the second feed inlet into light and heavy oil products.

2. The hydrogenation product separation system according to claim 1, characterized in that: A feed flash tank is connected in series on the connecting pipeline between the second stripping tower and the feed heating furnace, the liquid phase outlet at the bottom of the feed flash tank is connected to the feed heating furnace, and the gas phase outlet at the top of the feed flash tank is connected to the third feed port in the middle section of the distillation tower.

3. The hydrogenation product separation system according to claim 1 or 2, characterized in that: Also includes a first heat exchange device, The cold side of the first heat exchange device corresponds to the bottom oil outlet pipeline of the second stripping tower, and the hot side of the first heat exchange device corresponds to the feed pipeline of the reaction effluent.

4. The hydrogenation product separation system according to claim 2, characterized in that: The upper part of the fractionation tower is connected with a naphtha output pipeline, the middle part is connected with a diesel output pipeline, and the lower part is connected with a hydrogenated oil output pipeline.

5. The hydrogenation product separation system according to claim 1, characterized in that: The separation device comprises a hot high oil separator, a cold low oil separation pipeline connected to its gas phase outlet, and a hot low oil separation pipeline connected to its liquid phase outlet; The cold low oil separation pipeline is communicated with the first stripping tower; the hot low oil separation pipeline is communicated with the second stripping tower.

6. The hydrogenation product separation system according to claim 5, characterized in that: The separation device further comprises a cold high separator and a cold low separator arranged on the cold low oil separation pipeline, the inlet of the cold high separator is connected to the gas phase outlet of the hot high separator, the liquid phase outlet of the cold high separator is connected to the cold low separator, and the liquid phase outlet of the cold low separator is connected to the first stripping tower; The gas phase outlets of the cold high separator and the cold low separator are connected to the subsequent processing section.

7. The hydrogenation product separation system according to claim 6, characterized in that: The separation device also includes a hot low separator arranged on the hot low oil separation pipeline, the inlet of the hot low separator is connected to the liquid phase outlet of the hot high separator, the gas phase outlet of the hot low separator is connected to the inlet of the cold low separator, and the liquid phase outlet of the hot low separator is connected to the second stripping tower.

8. The hydrogenation product separation system according to claim 6, characterized in that: Also includes a second heat exchange device, The cold side of the second heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator, and the hot side of the second heat exchange device corresponds to the feed pipeline of the reaction effluent.

9. The hydrogenation product separation system according to claim 6, characterized in that: Also includes a third heat exchange device, The hot side of the third heat exchange device corresponds to the gas phase outlet pipeline of the hot high separator, and the cold side of the third heat exchange device corresponds to the liquid phase outlet pipeline of the cold low separator or the bottom oil outlet pipeline of the second stripping tower.

10. The hydrogenation product separation system according to claim 1, characterized in that: The first stripping tower is provided with a tower top gas reflux pipeline, and the tower top gas reflux pipeline is sequentially connected to the tower top gas outlet of the first stripping tower, the first reflux tank and the tower top gas reflux port; The fractionation tower is provided with a tower top oil reflux pipeline, and the tower top oil reflux pipeline is sequentially connected to the tower top oil outlet, the second reflux tank and the tower top oil reflux port of the fractionation tower.

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