Isobutane dehydrogenation co-production of mtbe after-propane removal column process device
Patent Information
- Application Number
- CN202522166627.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-14
- Publication Date
- 2026-09-11
- Estimated Expiration
- 2035-10-14
AI Technical Summary
然而，这种传统方案存在诸多不足：一方面，前置脱丙烷塔需处理冷箱产出的全部液相产品，导致脱丙烷塔及配套的进出料换热器、塔顶冷凝器、回流罐、塔底再沸器、塔底冷却器等设备尺寸较大，一次性投资成本较高，同时相关输送泵、回流泵及换热设备的运行负荷也较大，造成整体能耗偏高；另一方面，冷箱液相产品所蕴含的冷量未能得到有效利用，浪费了能源
本实用新型所述的异丁烷脱氢联产MTBE后置脱丙烷塔工艺装置，具有以下优势：首先，采用后置脱丙烷塔方案，脱丙烷塔的进料为经过MTBE生产单元处理后的醚后碳四，而非冷箱产出的全部液相产品，使得脱丙烷塔的进料量大幅减少，相应地，脱丙烷塔及配套的进出料换热器、塔顶冷凝器、回流罐、塔底再沸器、塔底冷却器等设备的尺寸得以缩小，有效降低了一次性投资成本；同时，碳四输送相关设备、回流泵以及脱丙烷塔塔底再沸器、塔底冷却器、塔顶冷凝器等的运行负荷明显降低，大幅减少了整体能耗，提升了生产的经济性。其次，将冷箱液相产品作为催化蒸馏塔塔顶冷却器的冷源，充分利用了冷箱液相产品的冷量，不仅实现了能源的高效回收利用，还能更好地控制催化蒸馏塔塔顶物料的冷却效果，有利于维持催化蒸馏塔内部操作条件的稳定，减少物料在分离过程中的损失，保障MTBE产品的收率与质量。再者，考虑到脱丙烷塔对进料压力的要求高于MTBE生产单元对进料压力的要求，后置脱丙烷塔方案无需为满足脱丙烷塔的高压需求而维持冷箱产品输送泵的高出口压力，可适当降低冷箱产品输送泵的出口压力，既减少了输送泵的设备投资，又降低了输送过程中的能耗，进一步优化了整个工艺系统的运行效率。此外，整个工艺装置的设备布局与物料流程设计合理，对装置整体投资以及最终产品的种类和规格影响甚微，在保障生产稳定性与产品质量的前提下，实现了能耗、成本与效率的综合优化，具有良好的工业应用价值。
Smart Images
Figure CN224735774U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of chemical equipment technology, specifically relating to a process device for isobutane dehydrogenation and MTBE co-production with a post-propane dehydrogenation tower. Background Technology
[0002] In the production process of MTBE from isobutane dehydrogenation in the chemical industry, the traditional process often adopts a pre-propane dehydrogenation tower scheme. This involves first depropanizing the liquid product from the cold box of the isobutane dehydrogenation unit, and then feeding the processed mixed C4 into the MTBE production unit. However, this traditional scheme has several drawbacks: Firstly, the pre-propane dehydrogenation tower needs to process all the liquid product from the cold box, resulting in a large size for the dehydrogenation tower and its associated inlet and outlet heat exchangers, top condenser, reflux tank, bottom reboiler, and bottom cooler, leading to high initial investment costs. Simultaneously, the operating load of related transfer pumps, reflux pumps, and heat exchange equipment is also high, resulting in overall high energy consumption. Secondly, the cold energy contained in the liquid product from the cold box is not effectively utilized, wasting energy. Furthermore, the pre-propane dehydrogenation tower requires high feed pressure. To meet the pressure requirements of the pre-propane dehydrogenation tower, the cold box product transfer pump needs to maintain a high outlet pressure, further increasing equipment investment and operating energy consumption, which is detrimental to improving the economy and efficiency of the production process. Utility Model Content
[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a process device for the dehydrogenation of isobutane and the co-production of MTBE followed by a propane removal tower. This device can reduce the size and feed rate of the propane removal tower and related equipment, while reducing the load on related equipment to reduce energy consumption; it uses the liquid phase product of the cold box to cool the top cooler of the catalytic distillation tower, which helps to stabilize its operation and reduce material loss; it can also reduce the outlet pressure of the cold box product transfer pump, further reducing investment and energy consumption.
[0004] This utility model is achieved using the following technical solution: The aforementioned isobutane dehydrogenation and MTBE co-production MTBE post-propane removal tower process unit includes a mixed C4 feed buffer tank and a methanol buffer tank. The inlet of the mixed C4 feed buffer tank is connected to the cold box of the isobutane dehydrogenation unit via a pipeline. The outlets of the mixed C4 feed buffer tank and the methanol buffer tank are respectively connected to the inlet of the etherification reactor via pipelines. The outlet of the etherification reactor is connected sequentially to the feed inlet of the catalytic distillation tower via a discharge buffer tank. The bottom outlet of the catalytic distillation tower is connected to the MTBE tank area via a pipeline. The top outlet of the catalytic distillation tower is connected to the top reflux tank of the catalytic distillation tower via a pipeline. The liquid phase outlet of the top reflux tank of the catalytic distillation tower is split into two paths via pipelines, one of which connects to... One path connects to the top inlet of the catalytic distillation column, and the other path connects to the inlet of the C4 residue washing column. The bottom outlet of the C4 residue washing column is connected to the methanol recovery column via a pipeline. The top outlet of the C4 residue washing column is connected to the inlet of the propane removal column via a C4 residue collection tank. The bottom outlet of the propane removal column is split into two paths via a pipeline: one path connects to the bottom circulation inlet of the propane removal column, and the other path is transported to the downstream unit via a mixed C4 transfer pump. The top outlet of the propane removal column is connected to the reflux tank of the propane removal column via a pipeline. The liquid phase outlet of the reflux tank of the propane removal column is split into two paths via a pipeline: one path connects to the top inlet of the propane removal column, and the other path connects to the C3 component tank area.
[0005] The gas phase outlets of the catalytic distillation tower top reflux tank and the propane removal tower reflux tank are respectively connected to the fuel gas system via pipelines.
[0006] The cold box, the mixed C4 feed buffer tank, the methanol buffer tank, the discharge buffer tank, the catalytic distillation column top reflux tank, the C4 residue collection tank, and the propane removal column reflux tank are each equipped with a feed pump on their outlet pipelines.
[0007] A catalytic distillation column top cooler is installed on the pipeline between the cold box and the mixed C4 feed buffer tank. The top outlet of the catalytic distillation column is connected to the heat source inlet of the catalytic distillation column top cooler via a pipeline. A catalytic distillation column top air cooler is also installed on the pipeline between the top outlet of the catalytic distillation column and the catalytic distillation column top cooler. The heat source outlet of the catalytic distillation column top cooler is connected to the catalytic distillation column top reflux tank via a pipeline.
[0008] The pipeline between the feed pump on the outlet pipeline of the discharge buffer tank and the catalytic distillation tower is equipped with a catalytic distillation tower inlet and outlet heat exchanger. The bottom outlet of the catalytic distillation tower is connected to the heat source inlet of the catalytic distillation tower inlet and outlet heat exchanger via a pipeline. The heat source outlet of the catalytic distillation tower inlet and outlet heat exchanger is connected to the heat source inlet of the MTBE product cooler via a pipeline. The heat source outlet of the MTBE product cooler is connected to the MTBE tank area via a pipeline.
[0009] A depropane tower feed heat exchanger is installed on the pipeline between the feed pump on the outlet pipeline of the C4 residue collection tank and the feed inlet of the depropane tower. The pipeline between the bottom outlet of the depropane tower and the mixing C4 conveying pump is connected in sequence to the heat source inlet and heat source outlet of the depropane tower feed heat exchanger. A depropane tower bottom cooler is also installed on the pipeline between the heat source outlet of the depropane tower feed heat exchanger and the mixing C4 conveying pump.
[0010] A reboiler for the depropanizer is installed on the pipeline between the bottom outlet of the depropanizer and the bottom circulation inlet of the depropanizer.
[0011] The working principle of the isobutane dehydrogenation and MTBE co-production MTBE post-propane dehydrogenation tower process unit is as follows: The liquid product from the isobutane dehydrogenation unit's cold box first enters the catalytic distillation column's overhead cooler for heat exchange, fully utilizing the cold box's own cooling capacity. This liquid product then enters the mixed C4 feed buffer tank. The mixed C4 in the feed buffer tank and the methanol in the methanol buffer tank are separately pipelined to the etherification reactor. In the etherification reactor, isobutene in the mixed C4 reacts with methanol to produce MTBE. The reaction product first enters the discharge buffer tank, then is pressurized by a feed pump and enters the catalytic distillation column's feed-discharge heat exchanger for heat exchange with the bottom discharge of the catalytic distillation column. The heat-exchanged reaction product is then sent to the catalytic distillation column. Inside the catalytic distillation column, MTBE is separated from the etherified C4 components. The MTBE at the bottom of the column first undergoes heat exchange in the catalytic distillation column's feed-discharge heat exchanger, then enters the MTBE product cooler for cooling, and finally is sent to the MTBE tank area for storage. The C4 component after etherification at the top of the catalytic distillation column is first cooled by the air cooler at the top of the column, then further cooled by the cooler at the top of the column. It then enters the reflux tank at the top of the column for gas-liquid separation. The separated gas phase is sent to the fuel gas system via pipeline, while the liquid phase is split into two paths: one returns to the top of the catalytic distillation column as reflux, and the other is sent to the C4 residue washing tower. In the C4 residue washing tower, methanol is removed from the C4 component after etherification. The residue containing methanol at the bottom of the tower is sent to the methanol recovery tower. The C4 component after etherification at the top of the column enters the C4 residue collection tank, and after being pressurized by a feed pump, it enters the propane stripper inlet / outlet heat exchanger to exchange heat with the bottom discharge of the propane stripper, and then is sent to the propane stripper. Within the propane stripper, post-etherification C4 is separated from C3 and lighter components. The post-etherification C4 (mainly isobutane) at the bottom of the stripper is split into two streams: one stream enters the stripper reboiler for heating and then returns to the bottom of the stripper for circulation; the other stream undergoes heat exchange in the stripper feed and discharge heat exchangers before entering the stripper bottom cooler for cooling, and finally is pumped to downstream units via a mixed C4 transfer pump. The C3 and lighter components at the top of the stripper enter the stripper reflux tank for gas-liquid separation. The separated gas phase is sent to the fuel gas system, while the liquid phase is split into two streams: one returns to the top of the stripper as reflux, and the other is sent to the C3 component storage tank area.
[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: The isobutane dehydrogenation and MTBE co-production process unit with a post-propane dehydrogenation tower has the following advantages: First, by adopting a post-propane dehydrogenation tower scheme, the feed to the dehydrogenation tower is post-ether C4 processed by the MTBE production unit, rather than all liquid products produced by the cold box. This significantly reduces the feed volume to the dehydrogenation tower. Consequently, the size of the dehydrogenation tower and its supporting feed and discharge heat exchangers, top condenser, reflux tank, bottom reboiler, and bottom cooler can be reduced, effectively lowering the initial investment cost. At the same time, the operating load of C4 conveying equipment, reflux pumps, and the dehydrogenation tower bottom reboiler, bottom cooler, and top condenser is significantly reduced, greatly reducing overall energy consumption and improving production economy. Secondly, using the cold box liquid product as the cold source for the overhead cooler of the catalytic distillation column fully utilizes its cooling capacity. This not only achieves efficient energy recovery and utilization but also better controls the cooling effect of the overhead material in the catalytic distillation column, helping to maintain stable operating conditions within the column, reducing material losses during separation, and ensuring the yield and quality of MTBE products. Furthermore, considering that the propane removal column requires a higher feed pressure than the MTBE production unit, the post-propane removal column scheme does not require maintaining a high outlet pressure of the cold box product transfer pump to meet the high pressure requirements of the propane removal column. The outlet pressure of the cold box product transfer pump can be appropriately reduced, decreasing equipment investment in the transfer pump and lowering energy consumption during the transfer process, further optimizing the overall process system's operating efficiency. In addition, the equipment layout and material flow design of the entire process unit are reasonable, having minimal impact on the overall investment of the unit and the type and specifications of the final product. While ensuring production stability and product quality, it achieves comprehensive optimization of energy consumption, cost, and efficiency, demonstrating significant industrial application value. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of the isobutane dehydrogenation and MTBE co-production MTBE post-propane dehydrogenation tower process unit according to the present invention; In the diagram: 1. Mixed C4 feed buffer tank; 2. Methanol buffer tank; 3. Cold box; 4. Etherification reactor; 5. Discharge buffer tank; 6. Catalytic distillation column; 7. MTBE tank area; 8. Catalytic distillation column top reflux tank; 9. C4 residue washing column; 10. Methanol recovery column; 11. C4 residue collection tank; 12. Propane removal column; 13. Mixed C4 transfer pump; 14. Propane removal column reflux tank; 15. C3 component tank area; 16. Fuel gas system; 17. Feed pump; 18. Catalytic distillation column top cooler; 19. Catalytic distillation column top air cooler; 20. Catalytic distillation column feed and discharge heat exchanger; 21. MTBE product cooler; 22. Propane removal column feed and discharge heat exchanger; 23. Propane removal column bottom cooler; 24. Propane removal column reboiler. Detailed Implementation
[0014] To make the objectives and technical solutions of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings.
[0015] Example 1 like Figure 1 As shown, the isobutane dehydrogenation and MTBE co-production MTBE post-propane removal tower process unit includes a mixed C4 feed buffer tank 1 and a methanol buffer tank 2. The inlet of the mixed C4 feed buffer tank 1 is connected to the cold box 3 of the isobutane dehydrogenation unit via a pipeline. The outlets of the mixed C4 feed buffer tank 1 and the methanol buffer tank 2 are respectively connected to the inlet of the etherification reactor 4 via pipelines. The outlet of the etherification reactor 4 is connected to the feed inlet of the catalytic distillation tower 6 via a discharge buffer tank 5. The bottom outlet of the catalytic distillation tower 6 is connected to the MTBE tank area 7 via a pipeline. The top outlet of the catalytic distillation tower 6 is connected to the top reflux tank 8 of the catalytic distillation tower via a pipeline. The liquid phase outlet of the top reflux tank 8 of the catalytic distillation tower is split into two paths via pipelines, one of which is connected to the catalytic distillation tower 6. The top inlet of distillation column 6 is connected to the inlet of C4 residue washing column 9; the bottom outlet of C4 residue washing column 9 is connected to methanol recovery column 10 via pipeline; the top outlet of C4 residue washing column 9 is connected to the inlet of propane dehydrogenation column 12 via C4 residue collection tank 11; the bottom outlet of propane dehydrogenation column 12 is split into two via pipeline, one connected to the bottom circulation inlet of propane dehydrogenation column 12, and the other transported to downstream units via mixed C4 transfer pump 13; the top outlet of propane dehydrogenation column 12 is connected to propane dehydrogenation column reflux tank 14 via pipeline; the liquid phase outlet of propane dehydrogenation column reflux tank 14 is split into two via pipeline, one connected to the top inlet of propane dehydrogenation column 12, and the other connected to C3 component tank area 15.
[0016] The gas phase outlets of the catalytic distillation tower top reflux tank 8 and the propane removal tower reflux tank 14 are respectively connected to the fuel gas system 16 via pipelines.
[0017] The cold box 3, the mixed C4 feed buffer tank 1, the methanol buffer tank 2, the discharge buffer tank 5, the catalytic distillation column top reflux tank 8, the C4 residue collection tank 11, and the propane removal column reflux tank 14 are each equipped with a feed pump 17 on their outlet pipelines.
[0018] A catalytic distillation column top cooler 18 is installed on the pipeline between the cold box 3 and the mixed C4 feed buffer tank 1. The top outlet of the catalytic distillation column 6 is connected to the heat source inlet of the catalytic distillation column top cooler 18 via a pipeline. A catalytic distillation column top air cooler 19 is also installed on the pipeline between the top outlet of the catalytic distillation column 6 and the catalytic distillation column top cooler 18. The heat source outlet of the catalytic distillation column top cooler 18 is connected to the catalytic distillation column top reflux tank 8 via a pipeline.
[0019] A catalytic distillation tower inlet and outlet heat exchanger 20 is installed on the pipeline between the feed pump 17 on the outlet pipeline of the discharge buffer tank 5 and the catalytic distillation tower 6. The bottom outlet of the catalytic distillation tower 6 is connected to the heat source inlet of the catalytic distillation tower inlet and outlet heat exchanger 20 through a pipeline. The heat source outlet of the catalytic distillation tower inlet and outlet heat exchanger 20 is connected to the heat source inlet of the MTBE product cooler 21 through a pipeline. The heat source outlet of the MTBE product cooler 21 is connected to the MTBE tank area 7 through a pipeline.
[0020] A depropane tower feed heat exchanger 22 is installed on the pipeline between the feed pump 17 on the outlet pipeline of the C4 residue collection tank 11 and the feed inlet of the depropane tower 12. The pipeline between the bottom outlet of the depropane tower 12 and the mixing C4 conveying pump 13 is connected in sequence to the heat source inlet and heat source outlet of the depropane tower feed heat exchanger 22. A depropane tower bottom cooler 23 is also installed on the pipeline between the heat source outlet of the depropane tower feed heat exchanger 22 and the mixing C4 conveying pump 13.
[0021] A reboiler 24 for the depropanizer is installed on the pipeline between the bottom outlet of the depropanizer 12 and the bottom circulation inlet of the depropanizer 12.
[0022] The specific steps for doing this are as follows: During operation, the feed pumps 17 on the outlet pipelines of each piece of equipment are started first to ensure smooth material transport. The liquid product produced by the cold box 3 of the isobutane dehydrogenation unit first enters the top cooler 18 of the catalytic distillation column, which serves as a cold source to exchange heat with the material from the top of the catalytic distillation column 6. After fully utilizing its own cooling capacity, it is then sent to the mixed C4 feed buffer tank 1 for temporary storage via the feed pump 17. The mixed C4 in the mixed C4 feed buffer tank 1 is transported by the feed pump 17 and enters the etherification reactor 4 together with the methanol in the methanol buffer tank 2, which is also transported by the feed pump 17. In the etherification reactor 4, the isobutene in the mixed C4 reacts with the methanol to produce MTBE. After the reaction is completed, the product enters the discharge buffer tank 5 for temporary storage. Then, it is pressurized by the feed pump 17 at the outlet of the discharge buffer tank 5 and sent to the catalytic distillation column feed heat exchanger 20 to exchange heat with the MTBE product from the bottom of the catalytic distillation column 6. The reaction product, after being heated by the heat exchange, enters the feed inlet of the catalytic distillation column 6 through the pipeline. Inside the catalytic distillation column 6, the MTBE product and the post-ether C4 component are separated through the synergistic effect of distillation and catalytic reaction. The MTBE product at the bottom of the column first flows into the inlet / outlet heat exchanger 20 of the catalytic distillation column, where it exchanges heat with the aforementioned reaction products to cool down. Then it enters the MTBE product cooler 21 for further cooling to a suitable temperature, and finally is transported to the MTBE tank area 7 for storage via pipeline. The post-ether C4 component at the top of the catalytic distillation column 6 first enters the top air cooler 19 of the catalytic distillation column via pipeline. After being cooled by air, it enters the top cooler 18 of the catalytic distillation column, where it exchanges heat with the liquid product from the cold box 3 for further cooling. Then it enters the top reflux tank 8 of the catalytic distillation column for gas-liquid separation. The gas phase generated by the separation is sent to the fuel gas system 16 for recycling via pipeline, while the liquid phase is divided into two paths. One path returns to the top feed inlet of the catalytic distillation column 6 via pipeline as reflux to maintain the operating balance within the catalytic distillation column 6. The other path is sent to the C4 residue washing tower 9 via pipeline. In the C4 residue washing tower 9, the methanol remaining in the C4 component after etherification is removed by water washing. The water washing residue containing methanol at the bottom of the C4 residue washing tower 9 is transported to the methanol recovery tower 10 for methanol recovery through pipeline. The C4 component after etherification after methanol removal at the top of the C4 residue washing tower 9 enters the C4 residue collection tank 11 for temporary storage. Then, it is pressurized by the feed pump 17 at the outlet of the C4 residue collection tank 11 and sent to the propane removal tower inlet and outlet heat exchanger 22 to exchange heat with the material sent from the bottom of the propane removal tower 12. The C4 component after etherification after heat exchange and temperature rise enters the tower inlet of the propane removal tower 12 through pipeline.Inside the propane stripper 12, the separation of post-etherified C4 from C3 and lighter components is achieved through distillation. The post-etherified C4 (mainly composed of isobutane) at the bottom of the propane stripper 12 is divided into two streams. One stream enters the reboiler 24 of the propane stripper through a pipeline for heating. The heated material returns to the bottom of the propane stripper 12 to form a cycle, maintaining the temperature gradient within the propane stripper 12. The other stream enters the feed heat exchanger 22 of the propane stripper through a pipeline to exchange heat with the aforementioned post-etherified C4 components and cool down. It then enters the bottom cooler 23 of the propane stripper for further cooling to a suitable temperature. Finally, it is transported to downstream units by the mixed C4 transfer pump 13. The C3 and lighter components at the top of the propane dehydrogenator 12 are fed into the propane dehydrogenator reflux tank 14 via pipeline for gas-liquid separation. The gas phase produced by separation is sent to the fuel gas system 16 for recycling via pipeline, while the liquid phase is divided into two paths. One path is returned to the top feed port of the propane dehydrogenator 12 via pipeline as reflux to maintain the operating balance within the propane dehydrogenator 12. The other path is transported to the C3 component tank area 15 via pipeline for storage, thus completing the entire isobutane dehydrogenation and MTBE production process.
Claims
1. A process unit for isobutane dehydrogenation and MTBE co-production followed by propane removal tower, characterized in that, The system includes a mixed C4 feed buffer tank (1) and a methanol buffer tank (2). The inlet of the mixed C4 feed buffer tank (1) is connected to the cold box (3) of the isobutane dehydrogenation unit via a pipeline. The outlets of the mixed C4 feed buffer tank (1) and the methanol buffer tank (2) are respectively connected to the inlet of the etherification reactor (4) via pipelines. The outlet of the etherification reactor (4) is connected to the feed inlet of the catalytic distillation column (6) via a discharge buffer tank (5). The bottom outlet of the catalytic distillation column (6) is connected to the MTBE tank area (7) via a pipeline. The top outlet of the catalytic distillation column (6) is connected to the top reflux tank (8) of the catalytic distillation column via a pipeline. The liquid phase outlet of the top reflux tank (8) of the catalytic distillation column is split into two paths via pipelines, one of which is connected to the top feed inlet of the catalytic distillation column (6), and the other... One path is connected to the inlet of the C4 residual liquid washing tower (9); the bottom outlet of the C4 residual liquid washing tower (9) is connected to the methanol recovery tower (10) via a pipeline; the top outlet of the C4 residual liquid washing tower (9) is connected to the inlet of the propane removal tower (12) via the C4 residual liquid collection tank (11); the bottom outlet of the propane removal tower (12) is split into two paths via a pipeline, one path is connected to the bottom circulation inlet of the propane removal tower (12), and the other path is transported to the downstream unit via the mixed C4 transfer pump (13); the top outlet of the propane removal tower (12) is connected to the propane removal tower reflux tank (14) via a pipeline; the liquid phase outlet of the propane removal tower reflux tank (14) is split into two paths via a pipeline, one path is connected to the top inlet of the propane removal tower (12), and the other path is connected to the C3 component tank area (15).
2. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 1, characterized in that, The gas phase outlets of the catalytic distillation tower top reflux tank (8) and the propane removal tower reflux tank (14) are respectively connected to the fuel gas system (16) via pipelines.
3. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 1, characterized in that, Feed pumps (17) are respectively installed on the outlet pipelines of the cold box (3), the mixed C4 feed buffer tank (1), the methanol buffer tank (2), the discharge buffer tank (5), the catalytic distillation tower top reflux tank (8), the C4 residual liquid collection tank (11), and the propane dehydrogenation tower reflux tank (14).
4. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 1, characterized in that, A catalytic distillation tower top cooler (18) is installed on the pipeline between the cold box (3) and the mixed C4 feed buffer tank (1). The top outlet of the catalytic distillation tower (6) is connected to the heat source inlet of the catalytic distillation tower top cooler (18) through a pipeline. A catalytic distillation tower top air cooler (19) is also installed on the pipeline between the top outlet of the catalytic distillation tower (6) and the catalytic distillation tower top cooler (18). The heat source outlet of the catalytic distillation tower top cooler (18) is connected to the catalytic distillation tower top reflux tank (8) through a pipeline.
5. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 3, characterized in that, A catalytic distillation tower inlet and outlet heat exchanger (20) is installed on the pipeline between the feed pump (17) on the outlet pipeline of the discharge buffer tank (5) and the catalytic distillation tower (6). The bottom outlet of the catalytic distillation tower (6) is connected to the heat source inlet of the catalytic distillation tower inlet and outlet heat exchanger (20) through a pipeline. The heat source outlet of the catalytic distillation tower inlet and outlet heat exchanger (20) is connected to the heat source inlet of the MTBE product cooler (21) through a pipeline. The heat source outlet of the MTBE product cooler (21) is connected to the MTBE tank area (7) through a pipeline.
6. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 3, characterized in that, A depropane tower feed heat exchanger (22) is provided on the pipeline between the feed pump (17) on the outlet pipeline of the C4 residual liquid collection tank (11) and the feed inlet of the depropane tower (12). The pipeline between the bottom outlet of the depropane tower (12) and the mixing C4 conveying pump (13) is connected in sequence to the heat source inlet and heat source outlet of the depropane tower feed heat exchanger (22). A depropane tower bottom cooler (23) is also provided on the pipeline between the heat source outlet of the depropane tower feed heat exchanger (22) and the mixing C4 conveying pump (13).
7. The isobutane dehydrogenation and MTBE co-production post-propane dehydrogenation tower process unit according to claim 1, characterized in that, A reboiler (24) for the depropanizer is installed on the pipeline between the bottom outlet of the depropanizer (12) and the bottom circulation inlet of the depropanizer (12).