Ether after carbon four 1-butene rectification zero steam energy-saving device and process

Abstract

This invention relates to the field of chemical separation technology, specifically to a zero-steam energy-saving device and process for the distillation of 1-butene in C4 after etherification. The zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification includes an upper column of a light-light separation tower, to which a C4 feedstock pipeline is connected. The upper column is connected to a lower column of the light-light separation tower via an intermediate pump. The lower column is connected to an upper column of a heavy-weight separation tower via a pipeline. The upper column is connected to the lower column of the heavy-weight separation tower via an intermediate pump. The upper column is connected to a reboiler of the light-light separation tower via a heat pump compressor. The upper column is connected to a reflux tank via the reboiler, and the reflux tank is connected to the upper column via a reflux pump. This invention increases the pressure of the gas phase at the top of the heavy-weight separation tower using a compressor, allowing the gas phase in the upper column to directly heat the light-light separation tower, reducing the steam consumption of the light-light separation tower to zero and improving the economic efficiency of the device.

Description

Technical Field

[0001] This invention relates to the field of chemical separation technology, specifically to a zero-steam energy-saving device and process for the distillation of 1-butene in C4 after etherification. Background Technology

[0002] 1-Butene (chemical formula C4H8) is a colorless, flammable unsaturated hydrocarbon with a double bond structure, produced at room temperature and normal pressure. It is an important basic chemical raw material. Industrially, it is mainly derived from petroleum refining and petrochemical processes, especially in high concentrations in mixed C4 fractions produced during catalytic cracking and steam pyrolysis.

[0003] The main industrial method for producing 1-butene is the mixed C4 fractionation process, which extracts 1-butene by separating the mixed C4 fractions produced by catalytic cracking or steam cracking. A common practice in mixed C4 fractionation is to convert or separate butadiene using techniques such as butadiene extraction and selective hydrogenation. Then, isobutane and isobutene are separated or converted through a combination and optimization of techniques such as distillation combined with isobutene n-formation (or etherification) or polyisobutene. Finally, 2-butene and n-butane, among other heavy components, are removed by extractive distillation or precision distillation to obtain the 1-butene product.

[0004] Chinese patent application CN112321382A, published on February 5, 2021, discloses an energy-saving process and apparatus for refining 1-butene with heat pump thermal integration. It employs a process of removing heavy components first and then light components, while simultaneously using heat pump distillation technology to reduce energy consumption. This invention already significantly reduces energy consumption compared to traditional processes, but further reductions are possible. Chinese patent application CN117362145A, published on January 9, 2024, discloses a highly efficient waste heat utilization energy-saving process and apparatus for refining 1-butene. While it also reduces energy consumption, it still requires steam as an external heat source, resulting in energy loss. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification. This device changes the limitation of heat pump distillation technology, which only allows one compressor to be used for one distillation column. In a dual-column distillation system for removing light and heavy components, one compressor can be used to achieve the goal of not requiring additional heat sources such as steam, which greatly reduces equipment investment.

[0006] Another objective of this invention is to provide a zero-steam energy-saving process for the distillation of 1-butene in C4 after etherification. By using a compressor to change the heat source level, the waste heat of the gas phase at the top of the column during the 1-butene recovery process is utilized, which has obvious energy-saving characteristics. By increasing the pressure of the gas phase at the top of the heavy removal column through the compressor, the gas phase of the upper column can directly heat the light removal column, reducing the steam consumption of the light removal column to zero and improving the economic efficiency of the equipment.

[0007] This invention is achieved using the following technical solution: The aforementioned zero-steam energy-saving device for the distillation of 1-butene in post-ether C4 includes an upper column of a light-light-removal tower, to which a post-ether C4 feed pipeline is connected. The upper column of the light-light-removal tower is connected to the lower column of the light-light-removal tower via an intermediate pump. The lower column of the light-light-removal tower is connected to the upper column of a heavy-removal tower via a pipeline. The upper column of the heavy-removal tower is connected to the lower column of the heavy-removal tower via an intermediate pump. The upper column of the heavy-removal tower is connected to the reboiler of the light-light-removal tower via a heat pump compressor. The upper column of the light-light-removal tower is connected to a reflux tank via the reboiler of the heavy-removal tower. The reflux tank is connected to the upper column of the light-light-removal tower via a reflux pump.

[0008] The reflux tank is connected to a non-condensable gas pipeline. The outlet of the reboiler of the heavy removal tower is connected to the lower tower of the heavy removal tower through a pipeline. The lower tower of the heavy removal tower is connected to the reboiler of the heavy removal tower through a pipeline. The lower tower of the light removal tower is connected to the upper tower of the light removal tower through a pipeline. A liquefied gas pipeline is connected to the pipeline between the reflux pump of the light removal tower and the upper tower of the light removal tower.

[0009] The lower tower of the light-light removal tower is connected to the inlet end of the reboiler of the light-light removal tower via a pipeline, and the outlet end of the reboiler of the light-light removal tower is connected to the lower tower of the light-light removal tower via a pipeline. The lower tower of the heavy-weight removal tower is connected to a heavy C4 product pipeline.

[0010] The reboiler of the light-weight removal tower is connected to the upper column of the heavy-weight removal tower through an auxiliary cooler. A throttling valve is provided between the auxiliary cooler and the upper column of the heavy-weight removal tower. A 1-butene product pipeline is connected to the pipeline between the auxiliary cooler and the throttling valve.

[0011] The process of the zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification includes the following steps: (1) The C4 mixture after etherification mainly includes n-butane, isobutane, trans-2-butene, 1-butene, isobutene, and cis-2-butene components. It enters the light phase removal tower for distillation. The gas phase at the top of the light phase removal tower enters the reboiler of the heavy phase removal tower to provide heat for the heavy phase removal tower. After further condensation, the non-condensable gas containing C2, C3, and isobutane enters the fuel gas pipeline. The liquid phase is pressurized by the reflux pump, and part of it is refluxed and part of it is extracted as liquefied gas product. (2) After the heavy component in the bottom of the light removal tower exchanges heat with the pressurized gas phase of the heavy removal tower, it returns to the bottom of the light removal tower to provide heat for the light removal tower; another part enters the heavy removal tower for distillation. (3) After being compressed by the compressor, the gas phase at the top of the heavy removal tower enters the reboiler of the light removal tower to provide heat for the light removal tower. After further condensation, part of it is collected as a product and part of it is refluxed back to the heavy removal tower after throttling and cooling. The bottom liquid of the heavy removal tower is collected as a heavy component rich in 2-butene and n-butane and sent to the alkylation unit.

[0012] The feed inlet of the light-light-removal tower is located at the bottom of the upper tower. The tower top pressure is 0.55 MPaG to 0.8 MPaG, preferably 0.65 MPaG to 0.75 MPaG. The tower top temperature is 40 to 60°C, preferably 55 to 58°C. The overall tower pressure drop is 100 kPa to 130 kPa, preferably 110 kPa to 120 kPa. The tower bottom temperature is 65 to 80°C, preferably 70 to 75°C. The tower top reflux ratio is 60 to 110.

[0013] The feed inlet of the deweight removal tower is located at the bottom of the upper tower. The top pressure of the tower is 0.2MPaG to 0.3MPaG, the top temperature of the tower is 25 to 35℃, the overall pressure drop of the tower is 120kPa to 140kPa, preferably 125kPa to 135Pa, the bottom temperature of the tower is 45 to 55℃, and the top reflux ratio is 10 to 20.

[0014] The compressor is located at the top of the de-weighting tower and has a compression ratio of 6 to 8.

[0015] The outlet pressure of the throttle valve is 0.01 MPa to 0.3 MPa greater than the top pressure of the deweight removal tower.

[0016] Add a compressor to the top of the existing heavy removal tower so that the gas phase at the top of the heavy removal tower can provide heat to the bottom of the light removal tower.

[0017] Lower the bottom temperature of the heavy removal tower to 45-50°C so that the gas phase at the top of the light removal tower can be used as a heat source to heat the heavy removal tower.

[0018] The compressor has a compression ratio of 6 to 8, and the compressed gas phase at the top of the tower can be used as a heat source to heat the light-duty tower.

[0019] Both the light-weight removal tower and the heavy-weight removal tower use structured packing, which is selected for its low pressure drop, strong mass transfer capacity, and ease of replacement. Both the light-weight removal tower and the heavy-weight removal tower are two separate towers.

[0020] Compared with the prior art, the beneficial effects of the present invention are: (1) The process described in this invention utilizes the technical means of changing the heat source level by a compressor to realize the utilization of the waste heat of the gas phase at the top of the tower during the 1-butene recovery process. It has obvious energy-saving characteristics. By increasing the gas phase pressure at the top of the heavy removal tower through the compressor, the gas phase at the top of the tower can directly supply heat to the light removal tower, reducing the steam consumption of the light removal tower to 0 and improving the economic efficiency of the device. (2) The process described in this invention utilizes the technical means of changing the gas phase pressure by a compressor to realize the utilization of the waste heat of the gas phase at the top of the tower during the 1-butene recovery process. It has obvious energy-saving characteristics. By reducing the pressure of the heavy removal tower by the compressor, the gas phase at the top of the light removal tower can directly supply heat to the heavy removal tower, reducing the steam consumption of the heavy removal tower to 0 and improving the economic efficiency of the device. (3) The technology described in this invention changes the limitation that a single compressor can only be used for one distillation column in heat pump distillation technology. In the dual-column distillation system for removing light and heavy components, a single compressor can be used to achieve the goal of not needing additional heat sources such as steam, which greatly reduces equipment investment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification according to the present invention; In the diagram: 1. Post-etherification C4 feedstock pipeline; 2. Upper section of the light component removal tower; 3. Reboiler of the heavy component removal tower; 4. Reflux tank; 5. Non-condensable gas pipeline; 6. Reflux pump of the light component removal tower; 7. Liquefied gas pipeline; 8. Intermediate pump of the light component removal tower; 9. Lower section of the light component removal tower; 10. Upper section of the heavy component removal tower; 11. Heat pump compressor; 12. Reboiler of the light component removal tower; 13. Auxiliary cooler; 14. 1-Butene product pipeline; 15. Throttling valve; 16. Intermediate pump of the heavy component removal tower; 17. Lower section of the heavy component removal tower; 18. Heavy C4 product pipeline. Detailed Implementation

[0022] To make the objectives and technical solutions of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1As shown, the zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification includes an upper column 2 for removing light components, a C4 feedstock pipeline 1 connected to the upper column 2, the upper column 2 for removing light components being connected to the lower column 9 for removing light components via an intermediate pump 8 for removing light components, the lower column 9 for removing light components being connected to the upper column 10 for removing heavy components via a pipeline, the upper column 10 for removing heavy components being connected to the lower column 17 for removing heavy components via an intermediate pump 16 for removing heavy components, the upper column 10 for removing heavy components being connected to the reboiler 12 for removing light components via a heat pump compressor 11, the upper column 2 for removing light components being connected to the reflux tank 4 via the reboiler 3 for removing heavy components, and the reflux tank 4 for removing light components being connected to the upper column 2 for removing light components via a reflux pump 6 for removing light components. A non-condensable gas pipeline 5 is connected to the reflux tank 4. The outlet of the reboiler 3 of the heavy removal tower is connected to the lower tower 17 of the heavy removal tower via a pipeline. The lower tower 17 of the heavy removal tower is connected to the reboiler 3 of the heavy removal tower via a pipeline. The lower tower 9 of the light removal tower is connected to the upper tower 2 of the light removal tower via a pipeline. A liquefied gas pipeline 7 is connected to the pipeline between the reflux pump 6 of the light removal tower and the upper tower 2 of the light removal tower. The lower tower 9 of the light removal tower is connected to the inlet end of the reboiler 12 of the light removal tower via a pipeline. The outlet end of the reboiler 12 of the light removal tower is connected to the lower tower 9 of the light removal tower via a pipeline. A heavy C4 product pipeline 18 is connected to the lower tower 17 of the heavy removal tower. The reboiler 12 of the light removal tower is connected to the upper tower 10 of the heavy removal tower via an auxiliary cooler 13. A throttling valve 15 is installed between the auxiliary cooler 13 and the upper tower 10 of the heavy removal tower. A 1-butene product pipeline 14 is connected to the pipeline between the auxiliary cooler 13 and the throttling valve 15.

[0024] The process for a zero-steam energy-saving distillation unit for 1-butene in C4 after etherification includes the following steps: (1) The C4 mixture after etherification enters the upper column 2 of the light removal column for distillation. The gas phase at the top of the light removal column enters the reboiler 3 of the heavy removal column to provide heat for the heavy removal column. After passing through the reflux tank 4, the non-condensable material containing isobutane enters the fuel gas pipeline. After the liquid phase is pressurized by the reflux pump, part of it is refluxed and part of it is extracted as liquefied gas product.

[0025] (2) The liquid in the bottom of the light removal tower is sent to the bottom of the light removal tower 9 via the intermediate pump 8. A portion of the heavy component in the bottom of the bottom of the light removal tower 9 enters the reboiler 12 of the light removal tower to exchange heat with the pressurized gas phase of the heavy removal tower, and then returns to the bottom of the bottom of the light removal tower 9 to provide heat for the light removal tower; another portion enters the top of the heavy removal tower 10 for distillation.

[0026] (3) The vapor phase at the top of the heavy removal tower is compressed by the heat pump compressor 11 and enters the reboiler 12 of the light removal tower to provide heat for the light removal tower. After being further condensed by the auxiliary cooler 13, part of it is collected as butene-1 product, and part of it is refluxed back to the heavy removal tower after being cooled by the throttling valve 15. The bottom liquid of the heavy removal tower is sent to the lower tower 9 of the light removal tower by the intermediate pump 16 of the heavy removal tower. The bottom liquid of the heavy removal tower is collected as a heavy C4 product rich in 2-butene and n-butane and sent to the alkylation unit.

[0027] According to the above process flow, the operating conditions of equipment such as the light-weight removal tower, heavy-weight removal tower, and compressor are as follows: Light-weight removal tower top pressure: 0.75 MPaG–0.80 MPaG; top temperature: 55–58℃; total tower pressure drop: 125 kPa–127 kPa; bottom temperature: 71–74℃; top reflux ratio: 64–110; Heavy-weight removal tower top pressure: 0.2 MPaG–0.3 MPaG; top temperature: 25–35℃; total tower pressure drop: 125 kPa–127 kPa; bottom temperature: 47–49℃; top reflux ratio: 15–17; compressor compression ratio: 6–8; throttle valve outlet pressure: 0.25 MPaG–0.30 MPaG.

[0028] Examples 1-5 1-Butene was recovered using the above-described apparatus and process. The process parameters for Examples 1-5 are shown in Table 1.

[0029] Table 1. Process parameters for Examples 1-5

[0030] In each embodiment, the feed rate of the post-etherified C4 mixture is 5.5 t / h, and the composition of the post-etherified C4 mixture feed is shown in Table 2 below: Table 2. Feed composition of post-etherified C4 mixture

[0031] The analytical data of the 1-butene product after separation by the method of the present invention are shown in Table 3 below: Table 3 1-Butene Product Analysis Data

[0032] The separated 1-butene product has high purity, and the purity and impurities of 1-butene meet the superior grade indicators of the corresponding industry standards.

[0033] Comparative Example 1 This comparative example uses a conventional process of first removing light and then heavy components, adopts the same mixed product composition and purity requirements as in Example 1, and has a total raw material volume of 5.5 t / h and a temperature of 38°C.

[0034] The conventional light component removal followed by heavy component removal process involves the etherified C4 mixture entering the top of the light component removal column. After distillation, light components such as C2, C3, and isobutane are removed. The top pressure of the light component removal column is 0.62 MPaG, the overall pressure drop is 132 kPa, the top temperature is 47.8℃, the bottom temperature is 67.0℃, and the reflux ratio is 21:1. Then, the mixture enters the heavy component removal column, where heavy components such as n-butane, cis-2-butene, and trans-2-butene are removed through distillation. The top pressure of the heavy component removal column is 0.4 MPaG, the overall pressure drop is 138 kPa, the top temperature is 43.8℃, the bottom temperature is 60.3℃, and the reflux ratio is 16.5. The final product is 1-butene with a purity of 99.3%. All equipment requiring heating is heated by steam, and all equipment requiring cooling is cooled by condensate.

[0035] Comparative Example 2 This comparative example uses a distillation method involving the removal of light components followed by the removal of heavy components, specifically a liquid flash heat pump distillation method with a de-heavy component tower, to recover 1-butene from a C4 mixture containing ether. The mixture composition and purity requirements are the same as in Example 1, with a total feed volume of 5.5 t / h and a temperature of 38 °C.

[0036] The reboiler liquid flash distillation heat pump distillation uses the reboiler liquid as the working fluid. A portion is collected as the product, and the remainder is used to provide additional cooling capacity. After being cooled by an auxiliary cooler, the liquid is throttled and depressurized. After depressurization, it enters a heat exchanger to absorb heat from the top gas and is converted into a gas phase. After being compressed and heated, it is used as a heat source for the reboiler.

[0037] The light component removal column had a top pressure of 0.62 MPaG, a total pressure drop of 132 kPa, a top temperature of 49.8℃, a bottom temperature of 67.5℃, and a reflux ratio of 75.7. The heavy component removal column had a top pressure of 0.4 MPaG, a total pressure drop of 138 kPa, a top temperature of 43.8℃, a bottom temperature of 60.4℃, and a reflux ratio of 14.6, ultimately yielding 1-butene with a purity of 99.3%. All equipment requiring heating was heated using steam, and all equipment requiring cooling was cooled using condensate.

[0038] Comparative Example 3 The distillation method described in Chinese Patent CN112321382A was used to recover 1-butene from a post-ether C4 mixture containing 1-butene. The mixture composition and purity requirements were the same as in Example 1, with a total feed volume of 5.5 t / h and a temperature of 38°C. The process parameters were simulated and calculated exactly according to the data disclosed in Example 2.

[0039] The pressure at the top of the light-weight removal tower is 0.65 MPaG, the temperature at the top of the tower is 48.8℃, the pressure at the bottom of the tower is 0.76 MPaG, the temperature at the bottom of the tower is 64.8℃, and the reflux ratio is 170.

[0040] The pressure at the top of the deweight removal tower is 0.60 MPaG, the temperature at the top of the tower is 55.5℃, the pressure at the bottom of the tower is 0.71 MPaG, the temperature at the bottom of the tower is 70.9℃, and the reflux ratio is 12.6.

[0041] Comparative Example 4 The distillation method in Chinese patent CN117362145A was used to recover 1-butene from the etherified C4 mixture containing 1-butene. The mixture composition and product purity requirements were the same as in Example 1. The total amount of raw material was 5.5 t / h, and the temperature was 38°C. According to the process flow of Example 1, the operating conditions of the light-weight removal tower, heavy-weight removal tower, compressor, and other equipment are as follows: Light-weight removal tower top pressure controlled at 0.62 MPaG, top temperature controlled at 48℃, total pressure drop 101 kPa, bottom temperature controlled at 66℃, and top reflux ratio 60; Heavy-weight removal tower upper tower top pressure controlled at 2.0 MPaG, top temperature controlled at 109℃, total pressure drop 52 kPa, bottom temperature controlled at 112℃, and top reflux ratio 56; Heavy-weight removal tower lower tower top pressure controlled at 0.45 MPaG, top temperature controlled at 49℃, total pressure drop 52 kPa, bottom temperature controlled at 60℃, and top reflux ratio 1; compressor discharge pressure is 2.2 MPaG. Throttling valve outlet pressure is 0.70 MPaG. Simulation calculations are performed based on the above data.

[0042] Examples 1 and Comparative Examples 1-4 were calculated based on a 1-butene yield of 99.0% and a purity of 99.3%. The simulations were performed using the chemical simulation software Aspen Plus, and the energy consumption was converted according to GB / T 50441-2016. The energy consumption of Examples 1 and Comparative Examples 1-4 was converted to standard oil for comparison, and the results are shown in Table 4.

[0043] Table 4. Comparison of energy consumption of the distillation methods in Example 1 and Comparative Examples 1-3

[0044] As can be seen from Table 4, from a thermodynamic perspective, the present invention has significant energy-saving characteristics when processing C4 mixtures containing n-butane, isobutane, trans-2-butene, 1-butene, isobutene, and cis-2-butene components, with energy consumption only 30-50% of that of other technologies.

Claims

1. A zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification, characterized in that, The light tower includes an upper tower (2), which is connected to a C4 feedstock pipeline (1) after etherification. The upper tower (2) is connected to the lower tower (9) via an intermediate pump (8). The lower tower (9) is connected to the upper tower (10) via a pipeline. The upper tower (10) is connected to the lower tower (17) via an intermediate pump (16). The upper tower (10) is connected to the reboiler (12) via a heat pump compressor (11). The upper tower (2) is connected to the reflux tank (4) via the reboiler (3). The reflux tank (4) is connected to the upper tower (2) via a reflux pump (6).

2. The zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification according to claim 1, characterized in that, The reflux tank (4) is connected to a non-condensable gas pipeline (5). The outlet of the heavy removal tower reboiler (3) is connected to the lower tower (17) of the heavy removal tower through a pipeline. The lower tower (17) of the heavy removal tower is connected to the reboiler (3) of the heavy removal tower through a pipeline. The lower tower (9) of the light removal tower is connected to the upper tower (2) of the light removal tower through a pipeline. A liquefied gas pipeline (7) is connected to the pipeline between the light removal tower reflux pump (6) and the upper tower (2) of the light removal tower.

3. The zero-steam energy-saving device for 1-butene distillation in C4 after etherification according to claim 1, characterized in that, The lower tower (9) of the light-light removal tower is connected to the inlet end of the reboiler (12) of the light-light removal tower through a pipeline, and the outlet end of the reboiler (12) of the light-light removal tower is connected to the lower tower (9) of the light-light removal tower through a pipeline. The lower tower (17) of the heavy-weight removal tower is connected to a heavy C4 product pipeline (18).

4. The zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification according to claim 1, characterized in that, The reboiler (12) of the light tower is connected to the upper tower (10) of the heavy tower through an auxiliary cooler (13). A throttle valve (15) is provided between the auxiliary cooler (13) and the upper tower (10) of the heavy tower. A 1-butene product pipeline (14) is connected to the pipeline between the auxiliary cooler (13) and the throttle valve (15).

5. A process employing the zero-steam energy-saving device for the distillation of 1-butene in C4 after etherification as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) The C4 mixture after etherification mainly includes n-butane, isobutane, trans-2-butene, 1-butene, isobutene, and cis-2-butene components. It enters the light phase removal tower for distillation. The gas phase at the top of the light phase removal tower enters the reboiler of the heavy phase removal tower to provide heat for the heavy phase removal tower. After further condensation, the non-condensable gas containing C2, C3, and isobutane enters the fuel gas pipeline. The liquid phase is pressurized by the reflux pump, and part of it is refluxed and part of it is extracted as liquefied gas product. (2) After the heavy component in the bottom of the light removal tower exchanges heat with the pressurized gas phase of the heavy removal tower, it returns to the bottom of the light removal tower to provide heat for the light removal tower; another part enters the heavy removal tower for distillation. (3) After being compressed by the compressor, the gas phase at the top of the heavy removal tower enters the reboiler of the light removal tower to provide heat for the light removal tower. After further condensation, part of it is collected as a product and part of it is refluxed back to the heavy removal tower after throttling and cooling. The bottom liquid of the heavy removal tower is collected as a heavy component rich in 2-butene and n-butane and sent to the alkylation unit.

6. The process according to claim 5, characterized in that, The feed inlet of the light-light-removal tower is located at the bottom of the upper tower. The pressure at the top of the tower is 0.55-0.8 MPaG, the temperature at the top of the tower is 40-60℃, the pressure drop across the entire tower is 100-130 kPa, the temperature at the bottom of the tower is 65-80℃, and the reflux ratio at the top of the tower is 60-110.

7. The process according to claim 5, characterized in that, The feed inlet of the deweight removal tower is located at the bottom of the upper tower. The pressure at the top of the tower is 0.2-0.3 MPaG, the temperature at the top of the tower is 25-35℃, the pressure drop across the entire tower is 120-140 kPa, the temperature at the bottom of the tower is 45-55℃, and the reflux ratio at the top of the tower is 10-20.

8. The process according to claim 5, characterized in that, The compressor is located at the top of the de-weighting tower and has a compression ratio of 6 to 8.

9. The process according to claim 5, characterized in that, The outlet pressure of the throttle valve is 0.01 to 0.3 MPa greater than the top pressure of the deweight removal tower.

Images