1-butene refining device with coupled dividing wall column and heat pump rectification

Abstract

The utility model belongs to the technical field of refining devices for chemical raw materials, and particularly relates to a 1-butene refining device with coupled dividing wall column and heat pump rectification. The 1-butene refining process device with coupled dividing wall column and heat pump rectification comprises a dividing wall column, a 1 # condenser and a compressor, a partition plate is arranged in the dividing wall column and divides the internal space of the dividing wall column into four parts, namely a public rectifying section, a feeding section, a discharging section and a public stripping section, a liquid collecting tray is arranged at the public rectifying section, and a liquid outlet is formed in the liquid collecting tray. A liquid outlet of the liquid collecting tray is connected with one end of a distribution pipeline outside the dividing wall column, the other end of the distribution pipeline is connected with the feeding section and the discharging section, and a regulating valve is arranged on the distribution pipeline; a tower bottom discharge port of the dividing wall tower is connected with the 1 # heat exchanger, the 1 # heat exchanger is connected with the throttle valve, and the throttle valve is connected with the 1 # condenser. The 1-butene refining device with coupled dividing wall column and heat pump rectification, provided by the utility model, is compact in structure and low in investment.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical raw material refining devices, and in particular relates to a 1-butene refining device with a bulkhead tower and a heat pump distillation coupling. Background Art

[0002] At present, 1-butene (C 4 H 8 ) is an important chemical raw material, mainly used as a comonomer in the production of linear low-density polyethylene (LLDPE) and poly-1-butene plastics. In the petrochemical and coal chemical industries, mixed C 4 Resource increase, C 4 The separation method for producing 1-butene has become the mainstream. The main production process of 1-butene is: MTBE unit post-ether mixed C 4 The trace amount of butadiene is removed by hydrogenation, and finally separated by ultra-precision distillation, including a light tower and a heavy tower. The light tower removes low-boiling carbon three, isobutane and azeotropes with water from carbon four, and the bottom product is then removed by a heavy tower to remove high-boiling n-butane and 2-butene, and 1-butene is obtained at the top of the tower. Although the process is simple, it requires a large number of plates, a large reflux ratio, and high energy consumption.

[0003] As a fully thermally coupled distillation tower type, the general form of the bulkhead tower is that the pre-fractionation tower and the main tower are located in the same tower shell and connected by gas-liquid phase streams at the upper and lower ends of the middle partition. Only one condenser and one reboiler are needed to realize the multi-component distillation process, avoiding the back-mixing effect of the internal logistics of the tower in the conventional design. It has the advantages of high thermodynamic efficiency of the distillation process, compact structure, small footprint, and low investment. Integrating the heat of the condenser and the reboiler can further improve the energy-saving efficiency of the bulkhead tower. Coupling the bulkhead tower with heat pump distillation has become a new energy-saving technology. For example, patent CN106083514A uses this technology to improve the thermodynamic efficiency of the distillation process, reduce equipment investment and process energy consumption. The technology in this regard adopts the tower top vapor recompression type heat pump distillation technology, but this process is limited to the selection of materials and has large limitations. For low-boiling point gases such as hydrogen in the tower top material, the compression ratio of the compressor will be increased, and the heat transfer coefficient of the heat exchanger will be reduced, thereby affecting the thermodynamic efficiency of the heat pump distillation. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the above-mentioned defects existing in the prior art, and to provide a 1-butene refining device with a bulkhead tower and a heat pump distillation coupling, wherein a single bulkhead tower is used for separation, the tower top is a light component, the 1-butene product is produced from the side line, and the tower bottom is a heavy component. The heat pump technology is used to integrate the heat of the tower top and the tower bottom, and the vaporization latent heat of the tower bottom material is used to cool the gas phase material at the tower top. The vaporized material is pressurized and heated by a compressor and returned to the tower bottom, thereby realizing a high-efficiency separation process of high-purity butene-1 by heat pump distillation.

[0005] The device of 1-butene refining process with a bulkhead tower and heat pump distillation coupling comprises a bulkhead tower, a No. 1 condenser and a compressor. A vertical partition extending from the axis of the tower body is arranged inside the bulkhead tower, and the partition divides the internal space of the bulkhead tower into four parts: a common distillation section, a feed section, a discharge section and a common stripping section. A liquid collecting tray is arranged in the common distillation section, and the liquid outlet of the liquid collecting tray is connected to one end of a distribution pipeline outside the bulkhead tower, and the other end of the distribution pipeline is connected to the feed section and the discharge section, and a regulating valve is arranged on the distribution pipeline; the bottom discharge port of the bulkhead tower is connected to the No. 1 heat exchanger, the No. 1 heat exchanger is connected to a throttle valve, the throttle valve is connected to the No. 1 condenser, the No. 1 condenser is connected to the compressor, and the compressor is connected to the bottom of the bulkhead tower.

[0006] The tower top gas outlet of the next-door tower is connected to the 1# condenser, the 1# condenser is connected to the 2# condenser, the 2# condenser is connected to the reflux tank, the reflux tank is connected to the reflux pump, and the reflux pump is connected to the tower top of the next-door tower.

[0007] The 1# heat exchanger is connected with a raw material pipeline, which is connected with the feed section;

[0008] The discharge section is provided with a side line in the tower, and a 3# condenser is provided on the side line in the tower;

[0009] A bottom pump is arranged at the bottom of the tower next door, and a 2# heat exchanger is arranged at the outlet of the bottom pump;

[0010] A light C4 delivery pipeline rich in isobutane is arranged at the outlet of the reflux pump.

[0011] The device for 1-butene refining process with a coupling of a bulkhead tower and a heat pump distillation has the following specific working process: after the etherified C4 mixture of MTBE undergoes a selective hydrogenation reaction, a mixture whose main components are hydrogen, water, methanol, C3, 1-butene, isobutane, normal butane, trans-2-butene, and cis-2-butene is obtained, and after heat exchange in the No. 1 heat exchanger, the mixture enters the bulkhead tower for distillation.

[0012] The bulkhead tower is provided with a vertical partition extending along the axis of the tower body. The vertical partition divides the space inside the tower into four parts: the common distillation section on the upper part of the partition, the feed section on the left side of the partition, the discharge section on the right side of the partition, and the common stripping section on the lower part of the partition. The material enters the feed section on the left side of the partition for preliminary distillation. Light components such as C3 and isobutane are evaporated from the top of the tower and enter the reflux tank after passing through the 1# condenser and the 2# condenser. The non-condensable gas containing a small amount of light components such as C3 and hydrogen is sent out from the top of the reflux tank. The liquid material is then pumped out by the reflux pump, with one part entering the top of the tower as reflux and the other part as a light C4 rich in isobutane.

[0013] After passing through the common distillation section, the reflux liquid from the top of the bulkhead tower is collected in the liquid collecting tray on the partition. The collected liquid is extracted by gravity and distributed to both sides of the partition. The flow rate is controlled by the regulating valve on the distribution pipeline to change the distribution ratio. The liquid phases entering both sides of the partition are the reflux liquid in the middle section of the feed side and the reflux liquid in the middle section of the discharge side. The material in the middle section of the discharge side of the partition is obtained after gas-liquid mass transfer, and the product 1-butene is extracted from the side line in the tower. The liquid phases on both sides of the partition enter the common stripping section and finally enter the bottom of the bulkhead tower. After the gas phase from the bottom of the tower passes through the common stripping section, the rising gas phase is distributed and enters both sides of the partition due to the pressure drop determined by the cross-sectional area on both sides of the partition and the tower plate. The bulkhead tower can be a plate tower, a packed tower, or a plate-packed mixed tower.

[0014] The next-door tower adopts the flash evaporation and recompression heat pump technology of the tower bottom liquid. The materials at the bottom of the tower are heavy components such as n-butane, trans-2-butene and cis-2-butene, which are divided into two streams. One stream is pumped out through the bottom pump of the tower and sent out after cooling by the 2# heat exchanger. The other stream is cooled by the 1# heat exchanger, reduced pressure by the throttle valve, and enters the 1# condenser for vaporization. The 1# condenser adopts a high-efficiency heat exchanger (the heat exchange tube adopts a high-evaporation tube, and many holes are processed on the outer surface to form a grid-like fine groove, and a grid channel interconnected under the tube surface is formed, forming a three-dimensional outer concave hole structure on the outer surface of the heat exchange tube). The temperature is reduced to provide cooling for the 1# condenser. After the vaporized material enters the compressor for compression, the pressure and temperature increase, and then returns to the tower bottom to complete the heat pump distillation process.

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

[0016] The whole device of the utility model adopts a bulkhead tower to separate the mixture components containing 1-butene after the selective hydrogenation reaction, adopts heat pump technology to heat-integrate the tower top and the tower bottom, utilizes the vaporization latent heat of the tower bottom material to cool the gas phase material at the tower top, and utilizes a compressor to pressurize and heat the vaporized gas to enter the tower bottom. Under the condition of meeting the product index and yield requirements of 1-butene, not only the thermodynamic efficiency of the distillation process is greatly improved, but also the investment in production equipment and process energy consumption are significantly reduced, the consumption of steam is completely eliminated and the amount of circulating water is greatly reduced, and the working pressure of the bulkhead tower is small, the operation is simple, and the floor space is small, so the economic benefit of the device is improved and it is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to the utility model.

[0018] Figure 2 This is a schematic diagram of the structure of the high evaporation tube used in the 1# condenser, where a is a schematic diagram of the surface structure, b is a schematic diagram of the cross-section, and c is an enlarged view of the surface.

[0019] In the figure: 1. next-door tower; 2. 1# heat exchanger; 3. reflux tank; 4. throttle valve; 5. 1# condenser; 6. 2# condenser; 7. compressor; 8. light C4 delivery pipeline rich in isobutane; 9. reflux pump; 10. partition; 11. common distillation section; 12. feed section; 13. discharge section; 14. common stripping section; 15. liquid collecting tray; 16. distribution pipeline; 17. regulating valve; 18. side line in the tower; 19. 3# condenser; 20. bottom pump; 21. 2# heat exchanger; 22. raw material pipeline. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.

[0021] The specific structures in the next-door tower described in the present invention are all existing settings, especially the liquid collecting tray, which are all existing equipment. Their function is to collect liquid and distribute the liquid phase and gas phase. They belong to conventional settings and are not the improvement points of the present invention. Therefore, no more discussion on their internal structure will be made.

[0022] Example 1

[0023] like Figure 1As shown, the device of the 1-butene refining process with a bulkhead tower and a heat pump distillation coupling comprises a bulkhead tower 1, a 1# condenser 5, and a compressor 7. A vertical partition 10 extending from the axis of the tower body is arranged inside the bulkhead tower 1. The partition 10 divides the internal space of the bulkhead tower 1 into four parts: a common distillation section 11, a feed section 12, a discharge section 13, and a common stripping section 14. A liquid collecting tray 15 is arranged in the common distillation section 11. The liquid outlet of the liquid collecting tray 15 is connected to one end of a distribution pipeline 16 outside the bulkhead tower 1. The other end of the distribution pipeline 16 is connected to the feed section 12 and the discharge section 13. A regulating valve 17 is arranged on the distribution pipeline 16. The bottom discharge port of the bulkhead tower 1 is connected to the 1# heat exchanger 2, the 1# heat exchanger 2 is connected to the throttle valve 4, the throttle valve 4 is connected to the 1# condenser 5, the 1# condenser 5 is connected to the compressor 7, and the compressor 7 is connected to the bottom of the bulkhead tower 1.

[0024] The top gas outlet of the next-door tower 1 is connected to the 1# condenser 5, the 1# condenser 5 is connected to the 2# condenser 6, the 2# condenser 6 is connected to the reflux tank 3, the reflux tank 3 is connected to the reflux pump 9, and the reflux pump 9 is connected to the top of the next-door tower 1.

[0025] The 1# heat exchanger 2 is connected with a raw material pipeline 22, and the raw material pipeline 22 is connected with the feed section 12;

[0026] The discharge section 13 is provided with a tower side line 18, and the tower side line 18 is provided with a 3# condenser 19;

[0027] A bottom pump 20 is provided at the bottom of the next-door tower 1, and a 2# heat exchanger 21 is provided at the outlet of the bottom pump 20;

[0028] The outlet of the reflux pump 9 is provided with a light C4 delivery pipeline 8 rich in isobutane.

[0029] The device for 1-butene refining process with a coupling of a bulkhead tower and a heat pump distillation has the following specific working process: after the etherified C4 mixture of MTBE undergoes a selective hydrogenation reaction, a mixture whose main components are hydrogen, water, methanol, C3, 1-butene, isobutane, normal butane, trans-2-butene, and cis-2-butene is obtained, and after heat exchange in the 1# heat exchanger 2, the mixture enters the bulkhead tower for distillation.

[0030] The next-door tower 1 is provided with a vertical partition 10 extending along the axis of the tower body, and the vertical partition 10 divides the space in the tower into four parts: a common rectification section 11 on the upper part of the partition, a feed section 12 on the left side of the partition, a discharge section 13 on the right side of the partition, and a common stripping section 14 on the lower part of the partition. The material enters the feed section 12 on the left side of the partition 10 for preliminary rectification, and light components such as C3 and isobutane are evaporated from the top of the tower, and enter the reflux tank 3 after passing through the 1# condenser 5 and the 2# condenser 6. The non-condensable gas containing a small amount of light components such as C3 and hydrogen is sent out from the top of the reflux tank 3, and the liquid material is then pumped out by the reflux pump 9, a part of which enters the top of the tower as reflux, and the other part is sent out as a light C4 rich in isobutane.

[0031] The reflux liquid at the top of the tower 1 is collected in the liquid collecting tray 15 on the upper side of the partition 10 after passing through the common distillation section 11. The collected liquid is extracted by gravity and distributed to both sides of the partition. The flow rate is controlled by the regulating valve 17 on the distribution pipeline to change the distribution ratio. The liquid phases entering the two sides of the partition 10 are the reflux liquid in the middle section of the feed side and the reflux liquid in the middle section of the discharge side. The material in the middle section of the discharge side of the partition 10 is subjected to gas-liquid mass transfer to obtain the side line 18 product 1-butene in the tower and exit the device. The liquid phases on both sides of the partition 10 enter the common stripping section 14 and finally enter the bottom of the tower 1 of the tower. After the gas phase from the bottom of the tower passes through the common stripping section 14, due to the pressure drop determined by the cross-sectional area on both sides of the partition 10 and the tower plate, the rising gas phase is flow-distributed and enters both sides of the partition 10. The tower 1 can be a plate tower, a packed tower or a plate-packed mixed tower.

[0032] The next-door tower 1 adopts the flash recompression heat pump technology of the tower bottom liquid. The materials at the bottom of the tower are heavy components such as n-butane, trans-2-butene and cis-2-butene, which are divided into two streams. One stream is pumped out through the bottom pump and sent to the 2# heat exchanger 21 for cooling and then sent out. The other stream is cooled through the 1# heat exchanger 2, decompressed through the throttle valve 4, and enters the 1# condenser 5 for gasification. The 1# condenser 5 adopts a high-efficiency heat exchanger (the heat exchange tube adopts a high evaporation tube, such as Figure 2 As shown in the figure, many holes are processed on the outer surface to form grid-like fine grooves, and interconnected grid channels are formed under the tube surface, forming a three-dimensional outer concave hole structure on the outer surface of the heat exchange tube), and the temperature is reduced to provide cooling for the 1# condenser 5. After the vaporized material enters the compressor 7 for compression, the pressure and temperature are increased, and then it returns to the tower kettle to complete the heat pump distillation process.

[0033] The utility model adopts the coupling of heat pump and next-door tower, which is more suitable for the system with non-condensable gas components such as hydrogen and carbon three on the top of the next-door tower of this process, cooperates with the efficient heat exchange of No. 1 condenser, reduces the temperature difference of the heat exchanger, and improves the thermodynamic efficiency of the heat pump distillation process.

Claims

1. A 1-butene refining device with a dividing wall tower and a heat pump distillation coupling, characterized in that: The invention comprises a dividing wall tower (1), a No. 1 condenser (5), and a compressor (7). A vertical partition (10) extending along the axis of the tower body is arranged inside the dividing wall tower (1). The partition (10) divides the internal space of the dividing wall tower (1) into four parts: a common rectification section (11), a feed section (12), a discharge section (13), and a common stripping section (14). A liquid collecting tray (15) is arranged in the common rectification section (11). The liquid outlet of the liquid collecting tray (15) is connected to the liquid outlet of the dividing wall tower (1). One end of the distribution pipeline (16) is connected, the other end of the distribution pipeline (16) is connected to the feed section (12) and the discharge section (13), and a regulating valve (17) is arranged on the distribution pipeline (16); the bottom discharge port of the bulkhead tower (1) is connected to the 1# heat exchanger (2), the 1# heat exchanger (2) is connected to the throttle valve (4), the throttle valve (4) is connected to the 1# condenser (5), the 1# condenser (5) is connected to the compressor (7), and the compressor (7) is connected to the bottom of the bulkhead tower (1); The top gas outlet of the next-door tower (1) is connected to the No. 1 condenser (5), the No. 1 condenser (5) is connected to the No. 2 condenser (6), the No. 2 condenser (6) is connected to the reflux tank (3), the reflux tank (3) is connected to the reflux pump (9), and the reflux pump (9) is connected to the top of the next-door tower (1).

2. The 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to claim 1, characterized in that: The 1# heat exchanger (2) is connected to a raw material pipeline (22), and the raw material pipeline (22) is connected to the feed section (12).

3. The 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to claim 1, characterized in that: The discharge section (13) is provided with a tower side line (18), and a 3# condenser (19) is provided on the tower side line (18).

4. The 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to claim 1, characterized in that: A tower bottom pump (20) is arranged at the bottom of the next-door tower (1), and a No. 2 heat exchanger (21) is arranged at the outlet of the tower bottom pump (20).

5. The 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to claim 1, characterized in that: The outlet of the reflux pump (9) is provided with a light C4 delivery pipeline (8) rich in isobutane.

6. The 1-butene refining device with a dividing wall tower and a heat pump distillation coupling according to claim 1, characterized in that: The ratio of the cross-sectional areas on both sides of the partition is 0.5 to 2.

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