Energy-saving negative pressure crude benzene distillation device
Patent Information
- Application Number
- CN202620108465.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2036-01-27
AI Technical Summary
可见，负压粗苯蒸馏工艺综合能耗降低了，但粗苯蒸馏能耗在焦化煤气净化装置中的占比还是处于前列，且蒸馏过程中的油汽和水蒸汽中的热量没有得到有效、充分利用，还是存在热量浪费的问题，能源利用率还有待提高；其次，在热富油进入脱苯塔进行蒸馏前，需要先使用蒸汽提升其温度，蒸汽消耗量大，排出后其中余热得不到充分利用
[0012]本实用新型运行时，富油通入液液换热器，利用脱苯塔底部排出的贫油余热对富油进行加热，富油温度从27℃左右升至140℃左右，然后富油再通入气液换热器，利用高温蒸汽对富油进一步加热，富油温度从140℃左右升至170℃左右，然后从脱苯塔的中部通入其中，同时，从脱苯塔的下部通入过热蒸汽，富油和过热蒸汽逆向接触换热，形成油汽和水蒸汽的混合汽不断上升，先进入上气筒，再从出气孔喷出，向环管和竖管内通入冷却介质，部分混合汽冷凝下来，冷凝下来的油相先下落聚集，形成自动回流液，经弯管落入脱苯塔，在脱苯塔内加强气液接触与传质，其余的混合汽则从脱苯塔的顶部通入冷却器，冷凝下来的气液混合物进入气液分离器进行气液两相分离，分离出的不凝汽相进入真空机进行抽吸，送至洗苯前煤气系统，分离出的液相进入油水分离器，进行粗苯与水的分离，即可得到粗苯产品。在本实用新型中，脱苯塔中的上升油汽和水蒸汽会进入上气筒，然后与竖管内的冷却介质换热，部分上升油汽和水蒸汽被冷凝下来，冷凝后的油相在自身的重力下，经弯管通入脱苯塔，完成回流液的自回流，回流液的量可根据需要调节冷却冷凝效率，如调节冷却介质种类、流速、温度等实现冷却冷凝效率的调节，相比于传统强制回流的结构来说，可减少设备投入，降低投入成本和生产成本，同时，通入竖管和环管内的冷却介质吸收油汽和水蒸汽中的余热，冷却器内的冷却介质进一步吸收油汽和水蒸汽中的余热，形成热的介质，可用于焦化厂其他工序的使用，或是满足冬季热水的使用，或是用于冬季采暖，提高焦化厂自身能源利用率，降低气液生产成本，实现能源的合理化利用；其次，本实用新型利用排出的热贫油对富油进行预热，再利用高温蒸汽进一步提升富油温度，温度有所下降的蒸汽通入蒸汽锅炉进行温度的提升，在蒸汽蓄热器进行储存，再返回到气液换热器中重复利用，在蒸汽锅炉内只需较少的热量即可将蒸汽温度提升到要求，减少了蒸汽生产的能耗，同时还实现了蒸汽的闭环循环使用，总体上减少了蒸汽的消耗量，减少了蒸汽消耗量，能够充分利用蒸汽中的热量，提高能源的利用率。综上所述，本实用新型具有可回收余热，热量浪费少，能源利用率高的优点。
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Figure CN224893376U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of crude benzene distillation apparatus, specifically to an energy-saving negative pressure crude benzene distillation apparatus. Background Technology
[0002] In the coal chemical coking process, the raw coal gas produced by coal pyrolysis is cooled and washed to absorb the benzene series hydrocarbons it contains. After a benzene removal process, crude benzene is obtained. Crude benzene is not a single substance, but a complex mixture with a wide boiling point range. Its main components include benzene (about 70-75%, boiling point 80.1℃), toluene (about 12-15%, boiling point 110.6℃), xylene (about 2-4%, boiling point range 138-144℃), aromatics, and non-aromatic impurities. The purpose of distillation is to separate and purify the main components in crude benzene according to their different boiling points to obtain pure benzene, toluene, xylene, and light solvent oil that meet national standards.
[0003] Currently, common crude benzene distillation processes generally include atmospheric distillation and vacuum distillation. Atmospheric distillation is technically mature and stable in operation, but it requires a large amount of steam; approximately 1.5 tons of 400℃ superheated steam are needed to obtain 1 ton of crude benzene. Vacuum distillation typically operates at a pressure of -70 kPag to -40 kPag, requiring a small investment in vacuum equipment, but it significantly reduces superheated steam consumption, requiring approximately 0.75 to 0.8 tons of superheated steam to obtain 1 ton of crude benzene. It is evident that the overall energy consumption of vacuum crude benzene distillation is reduced, but its energy consumption still ranks among the highest in coking gas purification units. Furthermore, the heat in the oil vapor and water vapor during distillation is not effectively and fully utilized, resulting in heat waste and requiring further improvement in energy utilization efficiency. Secondly, before the hot rich oil enters the benzene removal tower for distillation, steam is needed to raise its temperature, resulting in high steam consumption and insufficient utilization of residual heat after discharge. Therefore, it is an objective need to develop an energy-saving negative pressure crude benzene distillation device that can recover waste heat, has less heat waste, and has a high energy utilization rate. Utility Model Content
[0004] The purpose of this invention is to provide an energy-saving negative pressure crude benzene distillation device that can recover waste heat, has less heat waste, and has a high energy utilization rate.
[0005] The purpose of this utility model is achieved as follows: it includes a benzene removal tower, a cooler, and a gas-liquid separator. The top of the benzene removal tower is connected to the cooler, and the bottom of the cooler is connected to the top of the gas-liquid separator. A vacuum machine is connected to the top of the gas-liquid separator, and an oil-water separator is connected to the bottom of the gas-liquid separator. A liquid-liquid heat exchanger is connected to the bottom of the benzene removal tower. The oil-rich outlet of the liquid-liquid heat exchanger is connected to the gas-liquid heat exchanger, and the oil-rich outlet of the gas-liquid heat exchanger is connected to the middle of the benzene removal tower. A steam boiler and a steam accumulator are connected sequentially to the steam outlet of the gas-liquid heat exchanger. The outlet of the steam accumulator is connected to the steam inlet of the gas-liquid heat exchanger. An annular plate is provided at the top of the benzene removal tower. An upper air cylinder with a sealed top end is concentrically arranged on the annular plate. Several air outlets are evenly distributed on the cylinder wall of the upper air cylinder. Several vertical pipes are evenly distributed circumferentially in the annular area between the upper air cylinder and the side wall of the benzene removal tower. Annular pipes are provided at both the upper and lower ends of the vertical pipes. The benzene removal towers above and below the annular plate are connected by a bend pipe.
[0006] Furthermore, a jacket is installed on the side wall of the benzene removal tower above the annular plate. Furthermore, a heat-conducting ring plate is installed on the vertical pipe.
[0007] Furthermore, an air outlet is provided on the air outlet, and the air outlet is tangentially connected to the side wall of the upper air cylinder.
[0008] Furthermore, the outlet of the oil-water separator is connected to a cold water preheater, and the outlet of the cold water preheater is connected to the inlet of the steam boiler.
[0009] Furthermore, the oil outlet of the oil-water separator is connected to a rich oil preheater, and the rich oil outlet of the rich oil preheater is connected to the rich oil inlet of the liquid-liquid heat exchanger.
[0010] Furthermore, the diameter of the air outlet gradually decreases from bottom to top.
[0011] Furthermore, the condensate outlet of the gas-liquid heat exchanger is connected to the water inlet of the steam boiler via a connecting pipe.
[0012] In operation, the rich oil is introduced into a liquid-liquid heat exchanger, where the waste heat from the lean oil discharged from the bottom of the benzene stripping tower is used to heat the rich oil, raising its temperature from approximately 27°C to approximately 140°C. The rich oil is then introduced into a gas-liquid heat exchanger, where high-temperature steam further heats it, raising its temperature from approximately 140°C to approximately 170°C. This steam is then introduced from the middle of the benzene stripping tower, while superheated steam is introduced from the bottom. The rich oil and superheated steam exchange heat in counter-current contact, forming a mixture of oil vapor and water vapor that rises continuously, first entering the upper gas cylinder and then exiting from the outlet. The gas is ejected from the orifice and a cooling medium is introduced into the ring pipe and the vertical pipe. Part of the mixed gas condenses down. The condensed oil phase falls and accumulates first, forming an automatic reflux liquid, which falls into the benzene stripping tower through the benzene stripping tower. In the benzene stripping tower, the gas-liquid contact and mass transfer are enhanced. The remaining mixed gas is introduced into the cooler from the top of the benzene stripping tower. The condensed gas-liquid mixture enters the gas-liquid separator for gas-liquid two-phase separation. The separated non-condensable gas phase is pumped into the vacuum machine and sent to the pre-benzene gas system. The separated liquid phase enters the oil-water separator for crude benzene and water separation, thus obtaining the crude benzene product. In this invention, the rising oil vapor and water vapor in the benzene removal tower enter the upper gas cylinder and exchange heat with the cooling medium in the vertical pipe. Some of the rising oil vapor and water vapor are condensed. The condensed oil phase, under its own gravity, flows through the bend into the benzene removal tower, completing the self-reflux of the reflux liquid. The amount of reflux liquid can be adjusted to regulate the cooling and condensation efficiency as needed, such as by adjusting the type, flow rate, and temperature of the cooling medium. Compared to the traditional forced reflux structure, this reduces equipment investment and lowers both investment and production costs. Simultaneously, the cooling medium flowing into the vertical and ring pipes absorbs the residual heat from the oil vapor and water vapor, and the cooling medium in the cooler further absorbs the residual heat, forming a hot medium that can be used in other processes of the coking plant. The use of this technology can either meet the demand for hot water in winter or be used for winter heating, improving the energy utilization rate of the coking plant itself, reducing the cost of gas-liquid production, and achieving rational energy utilization. Secondly, this invention utilizes the discharged hot lean oil to preheat the rich oil, and then uses high-temperature steam to further increase the temperature of the rich oil. The steam, which has cooled down, is then fed into a steam boiler to raise its temperature, stored in a steam accumulator, and then returned to the gas-liquid heat exchanger for reuse. Only a small amount of heat is needed in the steam boiler to raise the steam temperature to the required level, reducing the energy consumption of steam production. At the same time, it also realizes the closed-loop circulation of steam, reducing the overall steam consumption and making full use of the heat in the steam to improve energy utilization efficiency. In summary, this invention has the advantages of recovering waste heat, minimizing heat waste, and achieving high energy utilization efficiency. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1A magnified structural diagram of node A in the middle; In the diagram: 1-Benzene removal tower, 2-Cooler, 3-Gas-liquid separator, 4-Vacuum machine, 5-Oil-water separator, 6-Liquid-liquid heat exchanger, 7-Gas-liquid heat exchanger, 8-Steam boiler, 9-Steam accumulator, 10-Ring plate, 11-Upper air cylinder, 12-Vertical pipe, 13-Ring pipe, 14-Bend, 15-Jacket, 16-Heat-conducting ring plate, 17-Outlet pipe, 18-Cold water preheater, 19-Rich oil preheater, 20-Connecting pipe. Detailed Implementation
[0014] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.
[0015] like Figures 1-2 As shown, this utility model includes a benzene removal tower 1, a cooler 2, and a gas-liquid separator 3. The top of the benzene removal tower 1 is connected to the cooler 2, and the bottom of the cooler 2 is connected to the top of the gas-liquid separator 3. A vacuum machine 4 is connected to the top of the gas-liquid separator 3, and an oil-water separator 5 is connected to the bottom of the gas-liquid separator 3. A liquid-liquid heat exchanger 6 is connected to the bottom of the benzene removal tower 1. The oil-rich outlet of the liquid-liquid heat exchanger 6 is connected to a gas-liquid heat exchanger 7, and the oil-rich outlet of the gas-liquid heat exchanger 7 is connected to the middle of the benzene removal tower 1. A steam boiler 8 and a steam storage tank are sequentially connected to the steam outlet of the gas-liquid heat exchanger 7. The outlet of the heat exchanger 9 and the steam accumulator 9 are connected to the steam inlet of the gas-liquid heat exchanger 7. The top of the benzene removal tower 1 is provided with an annular plate 10. An upper air cylinder 11 with an upper end sealed is concentrically provided on the annular plate 10. Several air outlets are evenly distributed on the cylinder wall of the upper air cylinder 11. Several vertical pipes 12 are evenly distributed in the annular area between the upper air cylinder 11 and the side wall of the benzene removal tower 1. In actual implementation, multiple layers of vertical pipes 12 can be set, with adjacent layers arranged alternately. Both the upper and lower ends of the vertical pipes 12 are provided with annular pipes 13. The benzene removal tower 1 above and below the annular plate 10 are connected by a bend pipe 14.
[0016] In operation, the rich oil is introduced into the liquid-liquid heat exchanger 6, where the residual heat from the lean oil discharged from the bottom of the benzene removal tower 1 is used to heat the rich oil, raising its temperature from approximately 27°C to approximately 140°C. Then, the rich oil is introduced into the gas-liquid heat exchanger 7, where high-temperature steam further heats it, raising its temperature from approximately 140°C to approximately 170°C. This steam is then introduced into the middle of the benzene removal tower 1, while superheated steam is introduced from the bottom. The rich oil and superheated steam exchange heat in counter-current contact, forming a mixture of oil vapor and water vapor that rises continuously. This mixture first enters the upper gas cylinder 11 and then is sprayed out from the outlet. Cooling medium is introduced into the ring pipe 13 and the vertical pipe 12. Part of the mixed vapor condenses down. The condensed oil phase falls and accumulates first, forming an automatic reflux liquid, which falls into the benzene stripping tower 1 through the benzene stripping tower 1. In the benzene stripping tower 1, gas-liquid contact and mass transfer are enhanced. The remaining mixed vapor is introduced into the cooler 2 from the top of the benzene stripping tower 1. The condensed gas-liquid mixture enters the gas-liquid separator 3 for gas-liquid two-phase separation. The separated non-condensable vapor phase enters the vacuum pump 4 for suction and is sent to the pre-benzene gas system. The separated liquid phase enters the oil-water separator 5 for crude benzene and water separation, and crude benzene product can be obtained.
[0017] In this invention, the rising oil vapor and water vapor in the benzene removal tower 1 enter the upper gas cylinder 11 and exchange heat with the cooling medium in the vertical pipe 12. Some of the rising oil vapor and water vapor are condensed. The condensed oil phase, under its own gravity, flows into the benzene removal tower 1 through the bend pipe 14, completing the self-reflux of the reflux liquid. The amount of reflux liquid can be adjusted to improve the cooling and condensation efficiency as needed, such as by adjusting the type, flow rate, and temperature of the cooling medium. Compared with the traditional forced reflux structure, this reduces equipment investment and lowers investment and production costs. At the same time, the cooling medium flowing into the vertical pipe 12 and the ring pipe 13 absorbs the residual heat from the oil vapor and water vapor. The cooling medium in the cooler 2 further absorbs the residual heat from the oil vapor and water vapor, forming a hot medium that can be used in coking plants. The use of steam in other processes can either meet the demand for hot water in winter or be used for winter heating, thereby improving the energy utilization rate of the coking plant itself, reducing the cost of gas-liquid production, and realizing the rational use of energy. Secondly, this utility model uses the discharged hot lean oil to preheat the rich oil, and then uses high-temperature steam to further increase the temperature of the rich oil. The steam with a slightly lower temperature is fed into the steam boiler 8 to raise the temperature, stored in the steam accumulator 9, and then returned to the gas-liquid heat exchanger 7 for reuse. Only a small amount of heat is needed in the steam boiler 8 to raise the steam temperature to the required level, reducing the energy consumption of steam production. At the same time, it also realizes the closed-loop circulation of steam, reducing the overall steam consumption and making full use of the heat in the steam to improve the energy utilization rate.
[0018] A jacket 15 is installed on the side wall of the benzene removal tower 1 above the ring plate 10. During operation, a cooling medium is introduced into the jacket 15. The cooling medium absorbs the residual heat in the oil vapor and water vapor, and improves the condensation efficiency of the oil vapor and water vapor. The cooling medium can be circulating water or cold water. After absorbing heat, it can be used for other coking processes or domestic heating.
[0019] A heat-conducting ring plate 16 is provided on the vertical pipe 12. The heat-conducting ring plate 16 is made of a material with good thermal conductivity, which can increase the contact area between the vertical pipe 12 and oil vapor and water vapor, thereby increasing the heat exchange area and ultimately improving the condensation efficiency of oil vapor and water vapor.
[0020] An outlet pipe 17 is provided on the outlet hole. The outlet pipe 17 is tangentially connected to the side wall of the upper gas cylinder 11. Oil vapor and water vapor are tangentially ejected from the outlet pipe 17, which can form a vortex in the annular area between the upper gas cylinder 11 and the side wall of the benzene removal tower 1, thereby increasing the condensation efficiency of the oil vapor and improving the recovery efficiency of the waste heat in the oil vapor.
[0021] The outlet of the oil-water separator 5 is connected to a cold water preheater 18, and the outlet of the cold water preheater 18 is connected to the inlet of the steam boiler 8. The cold water preheater 18 is an existing heat exchange device. The water separated by the oil-water separator 5 contains a certain amount of heat. If this heat is allowed to dissipate, it will undoubtedly result in a waste of heat. This heat is used to preheat the cold water and raise its temperature. The heated cold water is used as makeup water for the steam boiler 8, which can reduce the energy consumption of heating the cold water, thereby achieving energy saving and improving the production efficiency of evaporation.
[0022] The oil outlet of the oil-water separator 5 is connected to the rich oil preheater 19. The rich oil outlet of the rich oil preheater 19 is connected to the rich oil inlet of the liquid-liquid heat exchanger 6. The rich oil preheater 19 is an existing heat exchange device. In this utility model, the waste heat in the crude benzene discharged from the oil-water separator 5 is used to preheat the rich oil. This can increase the temperature of the rich oil to a certain extent, fully recover and utilize the waste heat of the crude benzene, reduce the loss and waste of waste heat, and improve the preheating effect of the rich oil.
[0023] The diameter of the vent gradually decreases from bottom to top. Oil vapor and water vapor are ejected from the vent and exchange heat with the cooling medium in the vertical pipe 12 and the ring pipe 13. As they rise, the oil vapor and water vapor ejected from the upper vent have a shorter time to participate in heat exchange, resulting in a poorer condensation effect. Therefore, the diameter of the vent gradually decreases from bottom to top, allowing more oil vapor and water vapor to be ejected from the lower vent, thus improving the condensation efficiency.
[0024] The condensate outlet of the gas-liquid heat exchanger 7 is connected to the inlet of the steam boiler 8 through the connecting pipe 20. The high-temperature steam heats the oil in the gas-liquid heat exchanger 7, and its own temperature will drop and some condensate will condense. This condensate has a high temperature. Discharging it from the gas-liquid heat exchanger 7 can prevent water accumulation in the gas-liquid heat exchanger 7 from affecting the heat exchange efficiency, and can make full use of the heat in the high-temperature condensate. The high-temperature condensate only needs a small amount of heat to regenerate high-temperature steam in the steam boiler 8.
Claims
1. An energy-saving negative pressure crude benzene distillation apparatus, comprising a benzene removal tower (1), a cooler (2), and a gas-liquid separator (3), characterized in that: The top of the benzene removal tower (1) is connected to the cooler (2), and the bottom of the cooler (2) is connected to the top of the gas-liquid separator (3). The top of the gas-liquid separator (3) is connected to a vacuum machine (4), and the bottom of the gas-liquid separator (3) is connected to an oil-water separator (5). The bottom of the benzene removal tower (1) is connected to a liquid-liquid heat exchanger (6), and the oil-rich outlet of the liquid-liquid heat exchanger (6) is connected to a gas-liquid heat exchanger (7). The oil-rich outlet of the gas-liquid heat exchanger (7) is connected to the middle of the benzene removal tower (1). The steam outlet of the gas-liquid heat exchanger (7) is sequentially connected to a steam boiler (8) and a steam storage tank. The outlet of the heat exchanger (9) and the steam inlet of the gas-liquid heat exchanger (7) are connected. The top of the benzene removal tower (1) is provided with an annular plate (10). An upper air cylinder (11) with an upper end sealed is concentrically provided on the annular plate (10). Several air outlet holes are evenly distributed on the cylinder wall of the upper air cylinder (11). Several vertical pipes (12) are evenly distributed in the annular area between the upper air cylinder (11) and the side wall of the benzene removal tower (1). Annular pipes (13) are provided at both the upper and lower ends of the vertical pipes (12). The benzene removal towers (1) above and below the annular plate (10) are connected by a bend pipe (14).
2. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: A jacket (15) is provided on the side wall of the benzene removal tower (1) above the ring plate (10).
3. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: A heat-conducting ring plate (16) is provided on the vertical pipe (12).
4. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: An air outlet is provided with an air outlet pipe (17), which is tangentially connected to the side wall of the upper air cylinder (11).
5. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: The outlet of the oil-water separator (5) is connected to a cold water preheater (18), and the outlet of the cold water preheater (18) is connected to the inlet of the steam boiler (8).
6. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: The oil outlet of the oil-water separator (5) is connected to the rich oil preheater (19), and the rich oil outlet of the rich oil preheater (19) is connected to the rich oil inlet of the liquid-liquid heat exchanger (6).
7. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: The diameter of the air outlet gradually decreases from bottom to top.
8. The energy-saving negative pressure crude benzene distillation apparatus according to claim 1, characterized in that: The condensate outlet of the gas-liquid heat exchanger (7) is connected to the water inlet of the steam boiler (8) through a connecting pipe (20).