Heat energy utilization system of C3 and C4 mixed dehydrogenation device

Abstract

The utility model discloses a heat energy utilization system of a C3 and C4 mixed dehydrogenation device, and relates to the technical field of heat energy utilization. According to the utility model, heat generated by a heat pump compressor is respectively used as a heat source of materials extracted from the side lines of a propane tower reboiler and a C3 and C4 separation tower A, heat of an aromatic solvent pipe system is used as a heat source of the reboiler of the C3 and C4 separation tower A, and heat of materials at the bottom of a C3 and C4 separation tower B is used as a heat source to exchange heat with materials at the inlet of the C3 and C4 separation tower A; surplus heat of the dehydrogenation device is fully utilized, steam consumption is reduced, and the purpose of saving energy is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of heat energy utilization, in particular to a heat energy utilization system for a C3 / C4 mixed dehydrogenation device. Background Technique

[0002] The dehydrogenation of alkanes to olefins has always been a research hotspot in the petrochemical field. As important chemical raw materials, olefins are widely used in various fields such as plastics, rubber, and fine chemicals. At present, many sets of alkanes dehydrogenation to olefins devices have been built at home and abroad.

[0003] At present, the production capacity of propane dehydrogenation to propylene devices is in excess. To expand the downstream industrial chain, some enterprises choose to transform propane dehydrogenation devices into C3 / C4 mixed dehydrogenation devices. The C3 / C4 mixed products need to enter the C3 / C4 separation tower system and the propylene / propane separation tower system respectively for product separation. In this process, a reboiler needs to be set at the bottom of the tower to heat the materials. During the transformation, the traditional process cannot use the original depropanizer for the transformed C3 / C4 separation tower, and a new C3 / C4 separation tower needs to be installed, resulting in a large investment; and using steam as the heat source to heat the materials has a very high energy consumption. The heat sources at the outlet of the heat pump compressor and the aromatic solvent heat source generated by the dehydrogenation device itself are generally directly cooled due to relatively low temperatures, and the energy consumption is also very high. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a heat energy utilization system for a C3 / C4 mixed dehydrogenation device, which uses the heat generated by the heat pump compressor as the heat source for the propane tower reboiler and the material withdrawn from the A side line of the C3 / C4 separation tower respectively, the heat of the aromatic solvent pipeline system as the heat source for the reboiler of the C3 / C4 separation tower A, and the heat of the bottom material of the C3 / C4 separation tower B as the heat source to exchange heat with the inlet material of the C3 / C4 separation tower A, fully utilizes the surplus heat of the dehydrogenation device, reduces steam consumption, and achieves the purpose of energy saving.

[0005] The technical solution of the utility model is as follows:

[0006] The heat energy utilization system of the C3 and C4 mixed dehydrogenation unit includes a C3 and C4 separation column A, a C3 and C4 separation column B, and a propane column. The C3 and C4 separation column A is connected with a C3 and C4 mixture feed pipeline, a top material discharge pipeline A, and a reboiler A, and is connected to the C3 and C4 separation column B through a bottom material discharge pipeline A. The C3 and C4 separation column B is connected with a top material discharge pipeline B, a bottom material discharge pipeline B, and a reboiler B. The C3 and C4 separation column A and the C3 and C4 separation column B are respectively connected to a condenser I through the top material discharge pipeline A and the top material discharge pipeline B. The condenser I is connected to a reflux tank through a pipeline. The reflux tank is connected to the C3 and C4 separation column A and the C3 and C4 separation column B respectively through a reflux pipeline, and is connected to the propane column through a C3 material discharge pipeline. The propane column is connected with a top material discharge pipeline C, a bottom material discharge pipeline C, and a reboiler C. The top material discharge pipeline C is connected with a first-stage inlet tank. The first-stage inlet tank is connected to the inlet of the first stage of the heat pump compressor through a pipeline. The outlet of the first stage of the heat pump compressor is connected to the reboiler C through a heat source feed pipeline I. The reboiler C is connected to the reflux port of the propane column through a heat source discharge pipeline I. The C3 and C4 separation column A is connected with a reboiler D through a side draw pipeline and a side return pipeline. The outlet of the second stage of the heat pump compressor is connected to the reboiler D through a heat source feed pipeline II. The reboiler D is connected to a second-stage inlet tank through a heat source discharge pipeline II. The second-stage inlet tank is connected with a propylene product out-of-plant pipeline, and is connected to the inlet of the second stage of the heat pump compressor through a top material discharge pipeline D. The bottom material outlet is connected to the propane column through a reflux pipeline.

[0007] Preferably, a heat exchanger is connected to the C3 and C4 mixture feed pipeline. The bottom material discharge pipeline B of the column is connected to the heat source inlet of the heat exchanger. The heat source outlet of the heat exchanger is connected with a C4 product pipeline.

[0008] Preferably, an aromatic hydrocarbon solvent feed pipeline is connected to the heat source inlet of the reboiler A, and an aromatic hydrocarbon solvent discharge pipeline is connected to the heat source outlet.

[0009] Preferably, a condenser II is connected to the aromatic hydrocarbon solvent discharge pipeline.

[0010] Preferably, the aromatic hydrocarbon solvent discharge pipeline is connected to the product gas compression unit of the dehydrogenation unit.

[0011] Preferably, a steam feed pipeline is connected to the heat source inlet of the reboiler B, and a steam condensate discharge pipeline is connected to the heat source outlet.

[0012] Preferably, a pump is connected to the bottom material discharge pipeline A of the column.

[0013] Preferably, a pump is connected to the reflux pipeline between the reflux tank and the C3 and C4 separation column A and the C3 and C4 separation column B.

[0014] Preferably, pumps are respectively connected to the bottom material discharge pipeline C of the tower and the pipeline for the propylene product to go out of the boundary.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] In the project of transforming propane dehydrogenation technology into C3 / C4 mixed dehydrogenation, the C3 / C4 separation tower of the utility model is divided into two tower systems, namely tower A (reusing the original depropanizer tower) and tower B (newly added). The heat generated by the heat pump compressor is respectively used as the heat source for the reboiler of the propane tower and the heat source for the material extracted from the side line of tower A of the C3 / C4 separation tower. The heat of the aromatic hydrocarbon solvent pipeline system is used as the heat source for the reboiler of tower A of the C3 / C4 separation tower. The heat of the bottom material of tower B of the C3 / C4 separation tower is used as the heat source to exchange heat with the inlet material of tower A of the C3 / C4 separation tower. The above can make full use of the surplus heat of the dehydrogenation device, reduce steam consumption, and achieve the purpose of energy conservation. Taking a 660,000-ton / year C3 / C4 mixed dehydrogenation device as an example, by adopting the technology of the utility model, the consumption of low-pressure steam can be saved by about 47 t / h, the consumption of circulating water can be saved by about 2,400 t / h, and the economic benefit can be created about 70 million / year. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the heat energy utilization system of the C3 / C4 mixed dehydrogenation device in Embodiment 1 of the utility model.

[0018] Figure 2 It is a schematic structural diagram of the heat energy utilization system of the C3 / C4 mixed dehydrogenation device in Comparative Example 1 of the utility model.

[0019] In the figure, 1. C3 / C4 separation tower A; 101. C3 / C4 mixture feed pipeline; 102. overhead material discharge pipeline A; 103. reboiler A; 104. bottom material discharge pipeline A; 105. side line extraction pipeline; 106. side line return pipeline; 107. reboiler D; 2. C3 / C4 separation tower B; 201. overhead material discharge pipeline B; 202. bottom material discharge pipeline B; 203. reboiler B; 3. propane tower; 301. overhead material discharge pipeline C; 302. bottom material discharge pipeline C; 303. reboiler C; 4. first-stage inlet tank; 5. heat pump compressor; 601. heat source feed pipeline 1; 602. heat source discharge pipeline 1; 7. condenser 1; 8. reflux tank; 801. C3 material discharge pipeline; 901. heat source feed pipeline 2; 902. heat source discharge pipeline 2; 10. second-stage inlet tank; 1001. propylene product out-of-boundary pipeline; 1002. overhead material discharge pipeline D; 11. heat exchanger; 12. C4 product pipeline; 1301. aromatic hydrocarbon solvent feed pipeline; 1302. aromatic hydrocarbon solvent discharge pipeline; 14. condenser 2; 1501. steam feed pipeline; 1502. steam condensate discharge pipeline; 16. condenser 3; 17. pump. Detailed Embodiments

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present utility model, the technical solutions of the present utility model will be clearly and completely described below in conjunction with the embodiments of the present utility model.

[0021] Embodiment 1

[0022] As Figure 1 shown, the thermal energy utilization system of the C3 and C4 mixed dehydrogenation device in this embodiment includes a C3 and C4 separation tower A1, a C3 and C4 separation tower B2, and a propane tower 3. The C3 and C4 separation tower A1 is connected with a C3 and C4 mixture feed pipeline 101, a top material discharge pipeline A102, and a reboiler A103, and is connected to the C3 and C4 separation tower B2 through a bottom material discharge pipeline A104. A pump 17 is connected to the bottom material discharge pipeline A104; the C3 and C4 separation tower B2 is connected with a top material discharge pipeline B201, a bottom material discharge pipeline B202, and a reboiler B203. The C3 and C4 separation tower A1 and the C3 and C4 separation tower B2 are respectively connected to a first condenser 7 through the top material discharge pipeline A102 and the top material discharge pipeline B201. The first condenser 7 is connected to a reflux tank 8 through a pipeline. The reflux tank 8 is connected to the C3 and C4 separation tower A1 and the C3 and C4 separation tower B2 respectively through a reflux pipeline. A pump 17 is connected to the reflux pipeline and is connected to the propane tower 3 through a C3 material discharge pipeline 801; the propane tower 3 is connected with a top material discharge pipeline C301, a bottom material discharge pipeline C302, and a reboiler C303. A pump 17 is connected to the bottom material discharge pipeline C302. The top material discharge pipeline C301 is connected to a first-stage inlet tank 4. The first-stage inlet tank 4 is connected to the first-stage inlet of a heat pump compressor 5 through a pipeline. The first-stage outlet of the heat pump compressor 5 is connected to the reboiler C303 through a first heat source feed pipeline 601. The reboiler C303 is connected to the reflux port of the propane tower 3 through a first heat source discharge pipeline 602; the C3 and C4 separation tower A1 is connected with a reboiler D107 through a side draw pipeline 105 and a side return pipeline 106. The second-stage outlet of the heat pump compressor 5 is connected to the reboiler D107 through a second heat source feed pipeline 901. The reboiler D107 is connected to a second-stage inlet tank 10 through a second heat source discharge pipeline 902. A third condenser 16 is connected to the second heat source discharge pipeline 902. The second-stage inlet tank 10 is connected with a propylene product out-of-bound pipeline 1001. A pump 17 is connected to the propylene product out-of-bound pipeline 1001 and is connected to the second-stage inlet of the heat pump compressor 5 through a top material discharge pipeline D1002. The bottom material outlet is connected to the propane tower 3 through a reflux pipeline.

[0023] Working principle:

[0024] The C3 and C4 mixture transported from other units enters the C3 and C4 separation column A1. After separation, the bottom material of the column is pressurized by pump 17 and then transported to the C3 and C4 separation column B2 for further separation. The bottom material of the C3 and C4 separation column B2 is transported as a C4 product to the outside of the plant.

[0025] The top materials of the C3 and C4 separation column A1 and the C3 and C4 separation column B2 are condensed by condenser 7 and then transported to the reflux drum 8. The materials in the reflux drum 8 are divided into two parts. One part is pressurized by pump 17 and returned as reflux materials to the C3 and C4 separation column A1 and the C3 and C4 separation column B2; the other part is transported to the propane column 3 for propane and propylene separation.

[0026] The bottom material of the propane column 3 is propane product, which is pressurized by pump 17 and then transported to other units in the dehydrogenation unit. The top material of the propane column 3 is transported to the first-stage inlet drum 4 and then transported to the heat pump compressor 5 for pressurization. The first-stage outlet material of the heat pump compressor 5 enters the reboiler C303 of the propane column 3, exchanges heat with the reboiling material at the bottom of the propane column 3, and then returns to the propane column 3 as a reflux material.

[0027] The propylene product at the bottom of the second-stage inlet drum 10 is pressurized and then transported to the off-site tank area. The top material of the second-stage inlet drum 10 is pressurized by the heat pump compressor 5, enters the reboiler D107 of the C3 and C4 separation column A1, exchanges heat with the side-draw material (i.e., the C3 and C4 mixture) of the C3 and C4 separation column A1, and then enters the condenser 16 for cooling. The cooled material then enters the second-stage inlet drum 10.

[0028] Among them, in this embodiment, a heat exchanger 11 is connected to the C3 and C4 mixture feed pipeline 101. The bottom stream discharge pipeline B is connected to the heat source inlet of the heat exchanger 11, and the heat source outlet of the heat exchanger 11 is connected to the C4 product pipeline 12. The C3 and C4 mixture first enters the heat exchanger 11, exchanges heat with the C4 product transported to the heat exchanger 11, and after being heated, is then transported to the C3 and C4 separation column A1. The C4 product is cooled by the heat exchanger 11 and then transported to the outside of the plant.

[0029] At the same time, the heat source inlet of the reboiler A103 is connected to the aromatic solvent feed pipeline 1301, the heat source outlet is connected to the aromatic solvent discharge pipeline 1302, the aromatic solvent discharge pipeline 1302 is connected to the condenser 14, and the aromatic solvent discharge pipeline 1302 is connected to the product gas compression unit of the dehydrogenation unit; the heat source inlet of the reboiler B203 is connected to the steam feed pipeline 1501, and the heat source outlet is connected to the steam condensate discharge pipeline 1502. The aromatic solvent transported from other units in the dehydrogenation unit enters the reboiler A103, exchanges heat with the reboiling material at the bottom of the C3 and C4 separation column A1, enters the condenser 14 for cooling, and after being cooled, returns to the original unit for continued use.

[0030] Comparative Example 1

[0031] As shown Figure 2 in the figure, the thermal energy utilization system of the C3-C4 mixed dehydrogenation unit of Comparative Example 1 includes a C3-C4 separation column A1 and a propane column 3. The C3-C4 separation column A1 is connected with a C3-C4 mixture feed pipeline 101, a top material discharge pipeline A102, a bottom material discharge pipeline A104 and a reboiler A103; the C3-C4 separation column A1 is connected with a condenser 7 through the top material discharge pipeline A102, the condenser 7 is connected with a reflux drum 8 through a pipeline, the reflux drum 8 is connected with the C3-C4 separation column A1 through a reflux pipeline, a pump 17 is connected to the reflux pipeline, and is connected with the propane column 3 through a C3 material discharge pipeline 801; the condenser 7 is connected with a circulating water feed pipeline and a circulating water discharge pipeline; the heat source inlet of the reboiler A103 is connected with a steam feed pipeline 1501, and the heat source outlet is connected with a steam condensate discharge pipeline 1502. A heat exchanger 11 is connected to the C3-C4 mixture feed pipeline 101, the bottom material discharge pipeline A of the column is connected to the heat source inlet of the heat exchanger 11, and the heat source outlet of the heat exchanger 11 is connected with a C4 product pipeline 12.

[0032] The propane column 3 is connected with a top material discharge pipeline C301, a bottom material discharge pipeline C302 and a reboiler C303. A pump 17 is connected to the bottom material discharge pipeline C302. The top material discharge pipeline C301 is connected with a first-stage inlet tank 4. The first-stage inlet tank 4 is connected with the first-stage inlet of a heat pump compressor 5 through a pipeline. The first-stage outlet of the heat pump compressor 5 is connected with the reboiler C303 through a heat source feed pipeline 601. The reboiler C303 is connected with the reflux port of the propane column 3 through a heat source discharge pipeline 602; the second-stage outlet of the heat pump compressor 5 is connected with a second-stage inlet tank 10 through a heat source feed pipeline 901. A condenser 16 is connected to the heat source feed pipeline 901. The condenser 16 is connected with a circulating water feed pipeline and a circulating water discharge pipeline; the second-stage inlet tank 10 is connected with a propylene product out-of-plant pipeline 1001. A pump 17 is connected to the propylene product out-of-plant pipeline 1001, and is connected with the second-stage inlet of the heat pump compressor 5 through a top material discharge pipeline D1002. The bottom material outlet is connected with the propane column 3 through a reflux pipeline.

[0033] Working principle:

[0034] The C3-C4 mixture transported from other units first exchanges heat with the C4 product coming out from the bottom of the C3-C4 separation column A1, and then enters the C3-C4 separation column A1. After separation, the bottom material is used as the C4 product, exchanges heat with the C3-C4 mixture and is cooled, and then transported out of the plant. The top material of the C3-C4 separation column A1 is condensed by the condenser 7 and then transported to the reflux drum 8. The material in the reflux drum 8 is divided into two parts. One part is pressurized by the pump 17 and returned to the C3-C4 separation column A1 as the reflux material, and the other part is transported to the propane column 3 for propane-propylene separation.

[0035] The bottom material of the propane tower 3 is propane product, which is pressurized by the pump 17 and then transported to other units in the dehydrogenation unit. The top material of the propane tower 3 is transported to the first-stage inlet tank 4, and then to the heat pump compressor 5 for pressurization. The material at the first-stage outlet of the heat pump compressor 5 enters the reboiler C303 of the propane tower 3, exchanges heat with the reboiling material at the bottom of the propane tower 3, and then returns to the propane tower 3 as reflux material. Part of the propylene product at the bottom of the second-stage inlet tank 10 is pressurized and transported to the off-site tank area, and the other part returns to the propane tower 3; the material at the top of the second-stage inlet tank 10 is pressurized by the heat pump compressor 5 and then cooled by the condenser III 16 and returned to the second-stage inlet tank 10.

[0036] The steam and circulating water consumption of the heat energy utilization systems in Example 1 and Comparative Example 1 are shown in Table 1:

[0037] Table 1 Steam and circulating water consumption of the heat energy utilization systems in Example 1 and Comparative Example 1

[0038] Comparative Example 1 Example 1 Energy consumption savings Steam t / h 77 30 47 Circulating water t / h 9400 7000 2400

[0039] As can be seen from Table 1, in the heat energy utilization system of Example 1, the C3-C4 separation tower is divided into two tower systems, Tower A (reusing the original propane tower 3) and Tower B (newly added). The heat generated by the heat pump compressor 5 is used as the heat source for the reboiler of the propane tower 3 and the side-stream withdrawn material of Tower A1 of the C3-C4 separation tower respectively. The heat of the aromatic solvent pipeline system is used as the heat source for the reboiler of Tower A1 of the C3-C4 separation tower. The heat of the bottom material of Tower B2 of the C3-C4 separation tower is used as the heat source to exchange heat with the inlet material of Tower A1 of the C3-C4 separation tower. The above can make full use of the surplus heat of the dehydrogenation unit, reduce steam consumption, and achieve the purpose of energy saving.

Claims

1. A heat energy utilization system for a C3-C4 mixed dehydrogenation unit, characterized in that it includes a C3-C4 separation column A (1), a C3-C4 separation column B (2) and a propane column (3). The C3-C4 separation column A (1) is connected with a C3-C4 mixture feed pipeline (101), a top product discharge pipeline A (102) and a reboiler A (103), and is connected to the C3-C4 separation column B (2) through a bottom product discharge pipeline A (104). The C3-C4 separation column B (2) is connected with a top product discharge pipeline B (201), a bottom product discharge pipeline B (202) and a reboiler B (203). The C3-C4 separation column A (1) and the C3-C4 separation column B (2) are respectively connected to a first condenser (7) through the top product discharge pipeline A (102) and the top product discharge pipeline B (201). The first condenser (7) is connected to a reflux drum (8) through a pipeline. The reflux drum (8) is connected to the C3-C4 separation column A (1) and the C3-C4 separation column B (2) respectively through a reflux pipeline, and is connected to the propane column (3) through a C3 material discharge pipeline (801); The propane column (3) is connected with a top product discharge pipeline C (301), a bottom product discharge pipeline C and a reboiler C (303). The top product discharge pipeline C (301) is connected with a first-stage inlet tank (4). The first-stage inlet tank (4) is connected to the first-stage inlet of a heat pump compressor (5) through a pipeline. The first-stage outlet of the heat pump compressor (5) is connected to the reboiler C (303) through a first heat source feed pipeline (601). The reboiler C (303) is connected to the reflux port of the propane column (3) through a first heat source discharge pipeline (602); The C3-C4 separation column A (1) is connected with a reboiler D (107) through a side draw pipeline (105) and a side return pipeline (106). The second-stage outlet of the heat pump compressor (5) is connected to the reboiler D (107) through a second heat source feed pipeline (901). The reboiler D (107) is connected to a second-stage inlet tank (10) through a second heat source discharge pipeline (902). The second-stage inlet tank (10) is connected with a propylene product out-of-plant pipeline (1001), and is connected to the second-stage inlet of the heat pump compressor (5) through a top product discharge pipeline D (1002). The bottom product outlet is connected to the propane column (3) through a reflux pipeline.

2. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein, A heat exchanger (11) is connected to the C3-C4 mixture feed pipeline (101). The bottom product discharge pipeline of the column is connected to the heat source inlet of the heat exchanger (11). The heat source outlet of the heat exchanger (11) is connected with a C4 product pipeline (12).

3. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein The heat source inlet of the reboiler A (103) is connected with an aromatic solvent feed pipeline (1301), and the heat source outlet is connected with an aromatic solvent discharge pipeline (1302).

4. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 3, wherein, A second condenser (14) is connected to the aromatic solvent discharge pipeline (1302).

5. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 4, characterized in that, The aromatic solvent discharge pipeline (1302) is connected to the product gas compression unit of the dehydrogenation unit.

6. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein The heat source inlet of the reboiler B (203) is connected with a steam feed pipeline (1501), and the heat source outlet is connected with a steam condensate discharge pipeline (1502).

7. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein, A pump (17) is connected to the bottom material discharge pipeline A (104).

8. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein, A pump (17) is connected to the reflux pipeline between the reflux drum (8), the C3 / C4 separation column A (1) and the C3 / C4 separation column B (2).

9. The thermal energy utilization system of the C3 and C4 mixed dehydrogenation device according to claim 1, wherein, Pumps (17) are respectively connected to the bottom material discharge pipeline C and the propylene product outlet pipeline (1001).

Images