A chemical production dehydration system

Abstract

This invention discloses a dehydration system for chemical production, belonging to the field of chemical production technology. This system utilizes a benzene / ethylbenzene dual-tower co-transport process, where the non-condensable gas line from the first reflux tank and the bottom discharge line are combined and then sent to the light component tower in two separate streams. This effectively reduces the heating time of the light component tower and decreases steam consumption during material preheating. Furthermore, the feed material in the middle of the tower heats the distillate, further improving distillation efficiency. In the styrene production process, by adding a packed auxiliary dehydration tower, free water in crude benzene is further removed based on the azeotropic principle, reducing the dehydration load on the light component tower and improving the benzene dehydration effect. This effectively avoids abnormal accidents such as catalyst deactivation and tower temperature and pressure fluctuations caused by the introduction of free water, improving the operational stability of the unit and solving the technical problem of high energy consumption in the benzene / light component tower co-transport dehydration process in styrene refining. It is mainly applied to dehydration in chemical production.

Description

Technical Field

[0001] This invention belongs to the field of chemical production technology, and specifically relates to a chemical production dehydration system. Background Technology

[0002] With the rapid development of global industrialization, people are constantly pursuing high-quality products to meet the needs of high-standard production and life. In the chemical production process, a small amount of free water mixed in oil will cause a series of problems such as tower temperature and pressure fluctuations, catalyst deactivation, and poor product quality. Therefore, oil dehydration plays an indispensable role in the field of industrial production, and the research and development of new oil dehydration technologies has gradually entered the vision of scientific researchers.

[0003] In the styrene production process, the introduction of free water will lead to the deactivation of alkylation, transalkylation and dehydrogenation catalysts, causing fluctuations in tower temperature and pressure, and even triggering unit interlock shutdown, increasing the operating cost of the unit.

[0004] On the other hand, in the current styrene oil refining process, the removal of free water mixed in with the oil by the benzene tower / light component tower combined transport technology is not only energy-intensive but also time-consuming. Therefore, it is particularly important to design a high-efficiency, low-energy dehydration technology. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a dehydration system for chemical production to solve the technical problem of high energy consumption in the dehydration of benzene tower / light component tower in the styrene refining process.

[0006] The above-mentioned technical objective of this invention is achieved through the following technical solution: a chemical production dehydration system, comprising a benzene tower, a light component tower, and a benzene / toluene separation tower; wherein,

[0007] The ethylbenzene feed line is connected to the benzene tower, which is equipped with a first reboiler. The benzene tower is connected to a benzene tower gas phase discharge line, which is connected to a first waste heat boiler. The first waste heat boiler is connected to a first reflux tank through a first condensate discharge line.

[0008] The first reflux tank has a raw benzene discharge pipeline connected to its bottom to the reaction system. A first delivery pump and a first water content analyzer are arranged sequentially on the raw benzene discharge pipeline. The dried benzene in the first reflux tank is sent to the reaction system for application by the first delivery pump. The first reflux tank is connected to a first reflux pipeline to the benzene tower. A second delivery pump is arranged on the first reflux pipeline.

[0009] The first reflux tank is also connected to a non-condensable gas pipeline and a first discharge pipeline. The non-condensable gas pipeline and the first discharge pipeline intersect and mix, and then the mixture is sent to the light component tower through the mixing pipeline.

[0010] The fresh benzene feed line is connected to the light component tower, which is equipped with a second reboiler. The bottom discharge line of the light component tower is connected to the gas phase discharge line of the benzene tower. A third delivery pump, a first processor, and a second water content analyzer are arranged sequentially on the bottom discharge line.

[0011] The light component tower has a gas phase discharge pipeline connected to the top of the light component tower and a second waste heat boiler. The second waste heat boiler is connected to the second reflux tank through a second condensate discharge pipeline. The second reflux tank has a second reflux pipeline connected to the light component tower. A fourth delivery pump is installed on the second reflux pipeline.

[0012] The crude benzene recovery pipeline is connected to the benzene / toluene separation tower. The crude benzene recovery pipeline is used to connect to the by-products of styrene production. The benzene / toluene separation tower is equipped with a third reboiler. The top of the benzene / toluene separation tower is connected to the gas phase discharge pipeline of the benzene / toluene separation tower. The gas phase discharge pipeline of the benzene / toluene separation tower is connected to the third waste heat boiler. A third water content analyzer is installed on the gas phase discharge pipeline of the benzene / toluene separation tower. The third waste heat boiler is connected to the third reflux tank through the third condensate discharge pipeline. The third reflux tank is connected to the third reflux pipeline, which is connected to the benzene / toluene separation tower. A sixth transfer pump is installed on the third reflux pipeline.

[0013] Furthermore: a diversion line is connected to the third reflux line to the auxiliary dehydration tower. The packing of the auxiliary dehydration tower is Pall rings or stepped rings. The auxiliary dehydration tower is equipped with a fourth reboiler. The auxiliary dehydration tower is connected to the light component tower via an auxiliary dehydration tower discharge line. A fourth water content analyzer, a second processor, and a fifth water content analyzer are sequentially arranged on the auxiliary dehydration tower discharge line. The auxiliary dehydration tower is also connected to the benzene / toluene separation tower gas phase discharge line via a gas phase discharge line.

[0014] Furthermore, the mixing pipeline is divided into a first branch pipeline and a second branch pipeline at its end, wherein the first branch pipeline is connected to the middle part of the light component tower and the second branch pipeline is connected to the bottom of the light component tower.

[0015] Furthermore: the second reflux tank is connected to the first dewatering pipeline to the condensate recovery system, and a fifth delivery pump is arranged on the first dewatering pipeline;

[0016] The third return tank is connected to the second dewatering pipeline to the condensate recovery system, and a seventh delivery pump is installed on the second dewatering pipeline.

[0017] Furthermore, the first, second, and third waste heat boilers are connected to the shell side of the steam pipeline network, thereby realizing resource reuse.

[0018] Furthermore, the packing material of the auxiliary dehydration tower is a Pall ring or a stepped ring.

[0019] Compared with the prior art, the present invention has the following advantages: (i) by adopting the benzene / ethylbenzene dual-tower combined transport process, the non-condensable gas line of the first reflux tank and the bottom discharge line of the tank are combined and then sent to the light component tower in two streams, which effectively reduces the heating time of the light component tower and reduces the steam consumption during the material preheating process. On the other hand, the feed material in the middle of the tower heats up the distillate in the tower, which further improves the distillation efficiency.

[0020] (ii) In the styrene production process, by adding a packed auxiliary dehydration tower, the free water in the crude benzene is further removed based on the azeotropic principle, reducing the dehydration load of the light component tower, improving the benzene dehydration effect, effectively avoiding abnormal accidents such as catalyst deactivation and tower temperature and pressure fluctuations caused by the introduction of free water, and improving the stability of the unit operation. Attached Figure Description

[0021] Figure 1 This is a flowchart of the first embodiment of the present invention;

[0022] Figure 2 This is a flowchart of the second embodiment of the present invention;

[0023] Figure 3 This is the present invention. Figure 2 Enlarged view of part A. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] In the description of the invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the first embodiment of the present invention, as Figure 1 As shown, a chemical production dehydration system is characterized by comprising a benzene tower 1, a light component tower 16, and a benzene / toluene separation tower 28; wherein,

[0027] The ethylbenzene feed line is connected to the benzene tower 1. The benzene tower 1 is equipped with a first reboiler 2. The benzene tower 1 is connected to the benzene tower gas phase discharge line 3. The benzene tower gas phase discharge line 3 is connected to the first waste heat boiler 4. The first waste heat boiler 4 is connected to the first reflux tank 6 through the first condensate discharge line 5.

[0028] The first reflux tank 6 has a raw benzene discharge pipeline 7 connected to the bottom of the first reflux tank 6 to the reaction system. A first transfer pump 8 and a first water content analyzer 9 are arranged in sequence on the raw benzene discharge pipeline 7. The dried benzene in the first reflux tank 6 is sent to the reaction system for application through the first transfer pump 8. The first reflux tank 6 is connected to the first reflux pipeline 10 to the benzene tower 1. A second transfer pump 12 is arranged on the first reflux pipeline 10.

[0029] The first reflux tank 6 is also connected to a non-condensable gas pipeline 13 and a first discharge pipeline 14. After the non-condensable gas pipeline 13 and the first discharge pipeline 14 intersect and mix, they are sent to the light component tower 16 through the mixing pipeline 15.

[0030] The fresh benzene feed line is connected to the light component tower 16. The light component tower 16 is equipped with a second reboiler 17. The bottom discharge line 18 of the light component tower 16 is connected to the gas phase discharge line 3 of the benzene tower. The third delivery pump 19, the first processor 20 and the second water content analyzer 21 are arranged in sequence on the bottom discharge line 18.

[0031] The light component tower 16 is connected to the light component tower gas phase discharge pipeline 22 at the top of the tower and connected to the second waste heat boiler 23. The second waste heat boiler 23 is connected to the second reflux tank 25 through the second condensate discharge pipeline 24. The second reflux tank 25 is connected to the light component tower 16 through the second reflux pipeline 26. The fourth transfer pump 27 is arranged on the second reflux pipeline 26.

[0032] The crude benzene recovery pipeline is connected to the benzene / toluene separation tower 28. The benzene / toluene separation tower 28 is equipped with a third reboiler 29. The top of the benzene / toluene separation tower 28 is connected to the benzene / toluene separation tower gas phase discharge pipeline 30. The benzene / toluene separation tower gas phase discharge pipeline 30 is connected to the third waste heat boiler 31. The third water content analyzer 32 is installed on the benzene / toluene separation tower gas phase discharge pipeline 30. The third waste heat boiler 31 is connected to the third reflux tank 34 through the third condensate discharge pipeline 33. The third reflux tank 34 is connected to the third reflux pipeline 35, which is connected to the benzene / toluene separation tower 28. The sixth transfer pump 36 is installed on the third reflux pipeline 35.

[0033] By adopting the above technical solution, the implementation method of this application is as follows: Ethylbenzene feed pipeline enters from outside the boundary and feeds ethylbenzene into benzene tower 1. Benzene tower 1 is a packed tower. Benzene tower 1 is heated by a first reboiler 2. The first reboiler 2 adopts an indirect heat exchange method, using circulating steam from outside the boundary to heat the condensate in the first reboiler 2. The vapor discharge pipeline 3 of the benzene tower is sent to a first waste heat boiler 4. The condensate formed in the first waste heat boiler 4 after heat exchange enters a first reflux tank 6 through a first condensate discharge pipeline 5. The first reflux tank 6 buffers the condensate. The dried raw material in the first reflux tank 6 is transported by a first transfer pump. 8. The dried raw material is sent to the reaction system for application. At this time, the dried raw material is a dehydrated liquid raw material. During the process, the first water content analyzer 9 detects the water content of the dried raw material entering the reaction system. At the same time, the second transfer pump sends part of the liquid raw material back to the benzene tower 1 through the first reflux pipeline to maintain the liquid level in the benzene tower 1. The non-condensable gas in the first reflux tank 6 is sent to the light component tower 16 for distillation and dehydration through the non-condensable gas pipeline 13. During this process, the first discharge pipeline 14 at the bottom of the first reflux tank 6 is connected to the liquid material in the first reflux tank 6 and the non-condensable gas are mixed in the mixing pipeline 15 and then sent to the light component tower 16.

[0034] Meanwhile, the fresh benzene feed pipeline connects to the outside and feeds fresh benzene into the light component tower 16. The light component tower 16 is heated by the second reboiler 17. The light component tower 16 is a packed tower, and the packing is one of metal packing, ceramic packing, or plastic packing. The second reboiler 17 adopts an indirect heat exchange form, using circulating steam connected to the outside to heat the condensate in the second reboiler 17. After heating, the low carbon hydrocarbons of the fresh benzene vaporize and come into contact with the packing to form adsorption and reaction, thereby removing the low carbon hydrocarbons. The bottom discharge pipeline 18 sends the bottom material of the light component tower 16 to the benzene tower gas phase discharge pipeline 3 through the third transfer pump 19. During this process, the first processor 20 on the bottom discharge pipeline 18 processes the bottom material. The first processor and the second processor are packed towers used to dehydrate the raw materials. The second water content analyzer 21 detects the water content of the oil.

[0035] The gas phase at the top of the light component tower 16 is sent to the second waste heat boiler 23 through the light component tower gas phase discharge pipeline 22. After heat exchange in the second waste heat boiler 23, the gas phase material is sent to the second reflux tank 25 through the second condensate discharge pipeline 24. The second reflux tank 25 establishes a reflux relationship between the second reflux pipeline 26 and the second reflux tank 25 through the fourth transfer pump 27.

[0036] Crude benzene obtained from styrene distillation is sent to benzene / toluene separation tower 28 for refining via a crude benzene recovery pipeline. Benzene / toluene separation tower 28 is heated by a third reboiler 29. After refining in benzene / toluene separation tower 28, toluene is obtained and sent to the toluene product storage area. The gaseous material generated during the refining process enters the third waste heat boiler 31 through the benzene / toluene separation tower gaseous discharge pipeline 30. The third water content analyzer 32 detects the water content of the material in the benzene / toluene separation tower gaseous discharge pipeline 30 in real time. The liquid oil condensed by heat exchange in the third waste heat boiler 31 is sent to the third reflux tank 34 through the third condensate discharge pipeline 33. The third reflux tank 34 establishes a reflux relationship between the third reflux pipeline 35 and the benzene / toluene separation tower 28 through the sixth transfer pump 36.

[0037] In the second embodiment of the present invention, as Figure 2 As shown, a chemical production dehydration system is characterized by: a branch line 37 connected to a third reflux line 35 to an auxiliary dehydration tower 38; the auxiliary dehydration tower 38 is packed with Pall rings or stepped rings; a fourth reboiler 39 is configured in the auxiliary dehydration tower 38; an auxiliary dehydration tower discharge line 40 is connected to a light component tower 16; a fourth water content analyzer 41, a second processor 42, and a fifth water content analyzer 43 are sequentially arranged on the auxiliary dehydration tower discharge line 40; and an auxiliary dehydration tower gas phase discharge line 44 is also connected to a benzene / toluene separation tower gas phase discharge line 30.

[0038] By adopting the above technical solution: a diversion pipeline is connected to the third reflux pipeline 35 to the auxiliary dehydration tower, the auxiliary dehydration tower 38 is heated by the fourth reboiler 39, the auxiliary dehydration tower discharge pipeline 40 sends the material into the light component tower 16, the second processor 42 processes the material, the fourth water content analyzer 41 and the fifth water content analyzer 43 detect the water content at both ends of the second processor 42, and the auxiliary dehydration tower gas phase discharge pipeline 44 at the top of the auxiliary dehydration tower 38 sends the gas phase raw material to the benzene / toluene separation tower gas phase discharge pipeline 30.

[0039] In the third embodiment of the present invention, as Figure 2 As shown, a chemical production dehydration system is provided, wherein the mixing pipeline 15 is divided into a first branch pipeline 45 and a second branch pipeline 46 at its end, wherein the first branch pipeline 45 is connected to the middle part of the light component tower 16, and the second branch pipeline 46 is connected to the bottom of the light component tower 16.

[0040] By adopting the above technical solution: by sending the hot material in the first reflux tank 6 to the light component tower 16 in two streams, one of which is fed from the bottom of the tower, the temperature of the liquid in the bottom of the light component tower 16 is rapidly increased, effectively reducing the heating time of the light component tower and reducing steam consumption during the material preheating process.

[0041] Another stream of feed from the middle of the light component column 16 further heats the distillate in the column, improving the distillation efficiency.

[0042] In the fourth embodiment of the present invention, as Figures 1-3 As shown, the second return tank 25 is connected to the first dewatering pipeline 47 to the condensate recovery system, and a fifth transfer pump 48 is arranged on the first dewatering pipeline 47.

[0043] The third return tank 34 is connected to the second dewatering pipeline 49 to the condensate recovery system, and a seventh transfer pump 50 is arranged on the second dewatering pipeline 49.

[0044] By adopting the above technical solution, the low-boiling-point benzene / water mixture generated during the distillation process of the light component tower 16 is separated by sedimentation in the second reflux tank 25. The high-density water settles into the water collection bag at the bottom of the second reflux tank 25 and is sent to the condensate recovery system by the fifth transfer pump 48 to achieve the removal of free water from the fresh benzene.

[0045] During the distillation process in the benzene / toluene separation tower 28, a low-boiling-point benzene / water mixture is generated and separated by sedimentation in the third reflux tank 34. The high-density water settles in the water collection bag at the bottom of the third reflux tank 34 and is sent to the condensate recovery system by the seventh transfer pump 50 to remove free water from the fresh benzene.

[0046] In the fifth embodiment of the present invention, as Figures 1-2 As shown, the first waste heat boiler 4, the second waste heat boiler 23 and the third waste heat boiler 31 are connected to the shell side of the steam pipeline network, thereby realizing resource reuse.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A chemical production dehydration system, characterized in that, It includes a benzene tower (1), a light component tower (16), and a benzene / toluene separation tower (28); among which, The ethylbenzene feed line is connected to the benzene tower (1), the benzene tower (1) is equipped with a first reboiler (2), the benzene tower (1) is connected to the benzene tower gas phase discharge line (3), the benzene tower gas phase discharge line (3) is connected to the first waste heat boiler (4), the first waste heat boiler (4) is connected to the first reflux tank (6) through the first condensate discharge line (5); The bottom of the first reflux tank (6) is connected to the raw benzene discharge pipeline (7) to the reaction system. The first transfer pump (8) and the first water content analyzer (9) are arranged in sequence on the raw benzene discharge pipeline (7). The dried benzene in the first reflux tank (6) is sent to the reaction system for application through the first transfer pump (8). The first reflux tank (6) is connected to the first reflux pipeline (10) to the benzene tower (1). The second transfer pump (12) is arranged on the first reflux pipeline (10). The first reflux tank (6) is also connected to a non-condensable gas pipeline (13) and a first discharge pipeline (14). The non-condensable gas pipeline (13) and the first discharge pipeline (14) intersect and mix, and then are sent to the light component tower (16) through the mixing pipeline (15). The fresh benzene feed line is connected to the light component tower (16). The light component tower (16) is equipped with a second reboiler (17). The bottom discharge line (18) of the light component tower (16) is connected to the gas phase discharge line (3) of the benzene tower. The third delivery pump (19), the first processor (20) and the second water content analyzer (21) are arranged in sequence on the bottom discharge line (18). The top of the light component tower (16) is connected to the light component tower gas phase discharge pipeline (22) and the second waste heat boiler (23). The second waste heat boiler (23) is connected to the second reflux tank (25) through the second condensate discharge pipeline (24). The second reflux tank (25) is connected to the light component tower (16) via the second reflux pipeline (26). The fourth transfer pump (27) is arranged on the second reflux pipeline (26). The crude benzene recovery pipeline is connected to the benzene / toluene separation tower (28). The benzene / toluene separation tower (28) is equipped with a third reboiler (29). The top of the benzene / toluene separation tower (28) is connected to the benzene / toluene separation tower gas phase discharge pipeline (30). The benzene / toluene separation tower gas phase discharge pipeline (30) is connected to the third waste heat boiler (31). The benzene / toluene separation tower gas phase discharge pipeline (30) is equipped with a third water content analyzer (32). The third waste heat boiler (31) is connected to the third reflux tank (34) through the third condensate discharge pipeline (33). The third reflux tank (34) is connected to the third reflux pipeline (35) and connected to the benzene / toluene separation tower (28). The third reflux pipeline (35) is equipped with a sixth transfer pump (36). A diversion line (37) is connected to the third reflux line (35) to the auxiliary dehydration tower (38). The auxiliary dehydration tower (38) is equipped with a fourth reboiler (39). The auxiliary dehydration tower (38) is connected to the auxiliary dehydration tower discharge line (40) and connected to the light component tower (16). The fourth water content analyzer (41), the second processor (42) and the fifth water content analyzer (43) are arranged in sequence on the auxiliary dehydration tower discharge line (40). The auxiliary dehydration tower (38) is also connected to the auxiliary dehydration tower gas phase discharge line (44) and connected to the benzene / toluene separation tower gas phase discharge line (30).

2. The chemical production dehydration system according to claim 1, characterized in that: The mixing pipeline (15) is divided into a first branch pipeline (45) and a second branch pipeline (46) at its end. The first branch pipeline (45) is connected to the middle of the light component tower (16), and the second branch pipeline (46) is connected to the bottom of the light component tower (16).

3. The chemical production dehydration system according to claim 1, characterized in that: The second return tank (25) is connected to the first dewatering pipeline (47) to the condensate recovery system, and a fifth transfer pump (48) is arranged on the first dewatering pipeline (47). The third return tank (34) is connected to the second dewatering pipeline (49) to the condensate recovery system, and a seventh transfer pump (50) is arranged on the second dewatering pipeline (49).

4. A chemical production dehydration system according to claim 2, characterized in that: The first waste heat boiler (4), the second waste heat boiler (23) and the third waste heat boiler (31) are connected to the shell side of the steam pipeline network, thereby realizing resource reuse.

5. A chemical production dehydration system according to claim 1, characterized in that: The packing material of the auxiliary dehydration tower (38) is a Pall ring or a stepped ring.

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