Phase change self-circulation waste heat heat pump coupling rectification system

Abstract

The utility model provides a phase change self-circulation waste heat heat pump coupling rectification system. Belongs to the technical field of waste heat utilization and rectification systems. According to the technical key points, the system comprises an evaporator, the evaporator is connected with a compressor suction tank through a sixth pipeline, the top of the compressor suction tank is connected with a compressor through a seventh pipeline, the bottom of the compressor suction tank is connected with an eighth pipeline, the compressor is connected with a second reboiler through a ninth pipeline, and the second reboiler is connected with a third reboiler through a ninth pipeline. The second reboiler is connected with the bottom of the fractionating tower through a tenth pipeline and an eleventh pipeline, one side of the second reboiler is connected with a throttle valve through a twelfth pipeline, and a thirteenth pipeline is connected between the throttle valve and the evaporator; the utility model aims to provide a phase change self-circulation waste heat heat pump coupling rectification system. The system is used for solving the problems that when an existing system is used, low-temperature heat energy is greatly wasted, energy consumption and cost are too large, and the environment is greatly influenced.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization and distillation systems, in particular to a phase-change self-circulating waste heat heat pump coupled distillation system. Background Art

[0002] During the operation of the fractionation towers in each unit of the oil refinery, a tower top condensation system and a tower bottom reboiler system are usually set up. The gas phase material at the top of the tower is cooled by air cooling, circulating water or other media, and the tower bottom reboiler system is often heated by steam, heating furnace, etc. For example, the rich liquid from the upstream unit of the solvent regeneration unit enters the fractionation tower after pressure increase and heat exchange; the bottom reboiler is provided with heat by 0.35-1.0MPaG steam to control the bottom temperature of the fractionation tower at about 125℃; the top gas of the fractionation tower is about 110℃, and is condensed and cooled to 40℃ by the top air cooler and the top aftercooler before entering the top reflux tank.

[0003] During the operation of the distillation tower, not only the air-cooling electricity and circulating cooling water of the cold utility are consumed, but also the low-pressure steam of the hot utility is consumed at the bottom of the tower, so there is a large space for the recovery and utilization of waste heat. Utility Model Content

[0004] The purpose of the utility model is to provide a phase-change self-circulating waste heat heat pump coupled distillation system to solve the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A phase-change self-circulating waste heat heat pump coupled distillation system comprises a fractionation tower, a fractionation tower feed pipeline is arranged on one side of the fractionation tower, an air cooler is connected to the top of the fractionation tower through a tower top gas phase pipeline, the air cooler is connected to a water cooler through a first pipeline, the water cooler is connected to a reflux tank through a second pipeline, a non-condensable steam pipeline is connected to the tank top of the reflux tank, a reflux pump is connected to the bottom of the reflux tank through a third pipeline, the reflux pump is connected to the reflux pipeline and a tower top product pipeline, the other end of the reflux pipeline is connected to the top of the fractionation tower, and the bottom of the fractionation tower is connected to a first reboiler through a fourth pipeline and a fifth pipeline;

[0007] An evaporator is connected to the gas phase pipeline at the top of the tower, and the evaporator is connected to the compressor suction tank through the sixth pipeline. The top of the compressor suction tank is connected to the compressor through the seventh pipeline, and the bottom of the compressor suction tank is connected to the eighth pipeline. The compressor is connected to the second reboiler through the ninth pipeline, and the second reboiler is connected to the bottom of the distillation tower through the tenth pipeline and the eleventh pipeline. A throttle valve is connected to one side of the second reboiler through the twelfth pipeline, and a thirteenth pipeline is connected between the throttle valve and the evaporator.

[0008] As a further solution of the utility model: the heat source of the first reboiler is low-pressure steam, and the first reboiler is connected to a steam condensate pipeline.

[0009] Compared with the prior art, the beneficial effects of the utility model are:

[0010] The phase-change self-circulating waste heat heat pump coupled distillation system transfers low-grade heat to high-grade heat for utilization through the circulation of specific working fluids in the heat pump system. The distillation tower operates. The material gas at the top of the distillation tower needs to be condensed through a condenser. The gaseous material is condensed into liquid material. In this process, the cooling system takes away a large amount of latent heat of the material. The evaporator of the heat pump closed circulation system replaces the top condenser; this part of the latent heat is exchanged with the working fluid in the heat pump closed circulation system, and the working fluid evaporates in the evaporator, absorbs heat and vaporizes; the vaporized circulating working fluid is compressed by a compressor, and after the temperature and pressure are increased, it is supplied to reboiler 2 to heat the material at the bottom of the distillation tower; the heated circulating working fluid vapor condenses and releases heat in the condenser, and condenses into a liquid phase; the liquid phase The working fluid returns to the evaporator after passing through the throttle valve, and this cycle simultaneously completes the condensation of the material at the top of the distillation tower and the heating of the material at the bottom of the tower; the coupled distillation system directly recovers the latent heat of the gas-phase material at the top of the tower and acts on the bottom of the distillation tower. The top and the bottom of the distillation tower affect each other. This system is suitable for distillation systems with a relatively small temperature difference between the top and the bottom of the distillation tower; the phase-change self-circulating waste heat heat pump coupled distillation system uses a proprietary working fluid, which effectively avoids the problem that the complex components of the gas-phase material at the top of the distillation tower may affect the bottom of the distillation tower, and improves the recovery and utilization rate of the latent heat of the gas-phase material at the top of the distillation tower. This system is not only suitable for solvent regeneration and gas fractionation devices, but also for energy recovery of BDO, styrene, PTMEG and other devices.

[0011] The system has the following features:

[0012] 1. Compression cycle: Closed system, compression closed heat pump system adopts the compression cycle principle, through the process of compressing the working medium such as refrigerant, increasing its temperature and pressure to achieve heat transfer. This cycle process includes several key steps such as evaporation, compression, condensation and expansion to achieve the extraction and transfer of heat energy.

[0013] 2. Closed system: The compression closed heat pump is a closed system. The working fluid does not come into direct contact with the external environment during the circulation process, thus avoiding the pollution and loss of the working fluid. The working fluid in the system can be recycled, reducing energy consumption and costs, and reducing environmental impact.

[0014] 3. Efficient energy conversion: The compression closed heat pump system achieves efficient energy conversion through compression cycle. By compressing the working fluid, the system can absorb heat from the low-temperature heat source and then release heat in the high-temperature heat source demand, thereby realizing the conversion and transfer of thermal energy. Compared with other traditional heating methods, the compression closed heat pump has higher energy utilization efficiency and can significantly save energy consumption.

[0015] 4. Wide temperature range: The compression closed waste heat distillation system can be applied to different temperature ranges, including low temperature, medium temperature and high temperature environments. By adjusting the working fluid type and working parameters in the compression cycle, heat energy conversion that meets different temperature requirements can be achieved.

[0016] 5. Strong controllability: The compression closed heat pump system can achieve precise control of the system operation by adjusting the operating parameters of the compressor such as pressure, flow, heat exchanger design and control system, etc. This allows the system to be adjusted according to actual needs to meet different process or heating needs.

[0017] Taking a company's solvent regeneration unit as an example, the gas phase cooling capacity at the top of the tower is 5344kw, which is not recycled and the low pressure at the bottom of the tower is consumed. 0.35MPag The steam is 13.8t / h. After adding the phase change self-circulating waste heat heat pump coupled with the distillation system, 3645kw of cooling capacity at the top of the tower can be recovered, saving 68.2% of the cooling load at the top of the tower and reducing the steam consumption of the reboiler at the bottom of the tower by 7.6t / h, which has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described in detail below in conjunction with the embodiments in the accompanying drawings, but this does not constitute any limitation to the present invention.

[0019] Figure 1 It is a process flow diagram of a phase change self-circulating waste heat heat pump coupled with a distillation system.

[0020] In the figure: 1, distillation tower; 2, distillation tower feed pipeline; 3, tower top gas phase pipeline; 4, air cooler; 5, first pipeline; 6, water cooler; 7, second pipeline; 8, reflux tank; 9, non-condensing steam pipeline; 10, third pipeline; 11, reflux pump; 12, reflux pipeline; 13, tower top product pipeline; 14, fourth pipeline; 15, fifth pipeline; 16, first reboiler; 17, evaporator; 18, sixth pipeline; 19, compressor suction tank; 20, seventh pipeline; 21, compressor; 22, eighth pipeline; 23, ninth pipeline; 24, second reboiler; 25, tenth pipeline; 26, eleventh pipeline; 27, twelfth pipeline; 28, throttle valve; 29, thirteenth pipeline; 30, low-pressure steam; 31, steam condensate pipeline. DETAILED DESCRIPTION

[0021] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0022] See also Figure 1 A phase-change self-circulating waste heat heat pump coupled distillation system comprises a fractionation tower 1, a fractionation tower feed pipeline 2 is arranged on one side of the fractionation tower 1, and the top of the fractionation tower 1 is connected to an air cooler 4 through a tower top gas phase pipeline 3, which is used for preliminary cooling of the tower top gas. The air cooler 4 is connected to a water cooler 6 through a first pipeline 5, which is used for further cooling of the tower top gas. The water cooler 6 is connected to a reflux tank 8 through a second pipeline 7, and the tank top of the reflux tank 8 is connected to a non-condensing steam pipeline 9, and the bottom of the reflux tank 8 is connected to a reflux pump 11 through a third pipeline 10, which plays a pressurizing role. The reflux pump 11 is connected to a reflux pipeline 12 and a tower top product pipeline 13, and the other end of the reflux pipeline 12 is connected to the top of the fractionation tower 1, and the bottom of the fractionation tower 1 is connected to a first reboiler 16 through a fourth pipeline 14 and a fifth pipeline 15, which is used for heating the material. The gas phase pipeline 3 at the top of the tower is connected with an evaporator 17 for evaporating the circulating working medium. The evaporator 17 is connected to the compressor suction tank 19 through the sixth pipeline 18, and the top of the compressor suction tank 19 is connected to a compressor 21 through the seventh pipeline 20 for compressing the evaporated circulating working medium. The bottom of the compressor suction tank 19 is connected with an eighth pipeline 22, and the compressor 21 is connected to the second reboiler 24 through the ninth pipeline 23. The working medium after being heated and pressurized by the compressor 21 enters the newly added second reboiler 24 to condense and release heat, replacing all or part of the heat provided by the first reboiler 16 provided by steam. The second reboiler 24 is connected to the bottom of the fractionation tower 1 through the tenth pipeline 25 and the eleventh pipeline 26, and one side of the second reboiler 24 is connected to a throttle valve 28 through the twelfth pipeline 27, and the throttle valve 28 and the evaporator 17 are connected with a thirteenth pipeline 29.

[0023] Furthermore, the heat source of the first reboiler 16 is low-pressure steam 30 , and the first reboiler 16 is connected to a steam condensate pipeline 31 .

[0024] Process: rich amine liquid enters the fractionation tower 1 through the fractionation tower feed pipeline 2, the resolved acid gas is sent from the top of the fractionation tower 1 to the air cooler 4 through the tower top gas phase pipeline 2 3 for preliminary cooling, the preliminary cooled acid gas is sent to the water cooler 6 through the first pipeline 5 for further cooling, the cooled acid gas enters the reflux tank 8 through the second pipeline 7, the acid gas in the reflux tank 8 is sent to the acid gas pipeline network through the non-condensable steam pipeline 9; acid water is extracted from the bottom of the reflux tank 8, pressurized by the reflux pump 11 through the third pipeline 10, and returned to the upper part of the fractionation tower 1 through the reflux pipeline 12 for reflux; the material at the bottom of the fractionation tower 1 enters the first reboiler 16 through the fourth pipeline 14 for heating, and the heated material returns to the fractionation tower 1 through the fifth pipeline 15; the low-pressure steam 30 is used as the heat source of the first reboiler 16, and the condensed water after heat exchange is returned to the condensate pipeline network through the steam condensate pipeline 31; the acid gas at the top of the fractionation tower 1 is The gas phase pipeline 3 at the top of the tower enters the evaporator 17, and the latent heat in the cooling process is exchanged with the working fluid in the phase change self-circulation waste heat distillation. The working fluid evaporates and absorbs heat and gasifies in the evaporator 17; the vaporized working fluid enters the compressor suction tank 19 through the sixth pipeline 18, and the working fluid in the compressor suction tank 19 is sent to the compressor 21 through the seventh pipeline 20 at the top for compression; the working fluid heated and pressurized by the compressor 21 is sent to the newly added second reboiler 24 through the ninth pipeline 23 to condense and release heat, replacing part of the steam to provide heat for the first reboiler 16; the material at the bottom of the distillation tower 1 enters the newly added second reboiler 24 through the tenth pipeline 25 to remove heat, and the material after removing heat returns to the bottom of the distillation tower 1 through the eleventh pipeline 26; the condensed working fluid is sent to the throttle valve 28 through the twelfth pipeline 27, and the pressure is reduced by the throttle valve 28 and re-enters the evaporator 17 through the thirteenth pipeline 29 to complete the heat recovery cycle.

[0025] The above embodiments are preferred implementation modes of the present invention and are only used to facilitate the explanation of the present invention. They are not intended to limit the present invention in any form. Any person with ordinary knowledge in the relevant technical field, if they do not depart from the scope of the technical features of the present invention, can make equivalent embodiments by partial changes or modifications to the technical contents disclosed in the present invention, and they still fall within the scope of the technical features of the present invention without departing from the technical features of the present invention.

Claims

1. A phase-change self-circulating waste heat heat pump coupled distillation system, comprising a fractionation tower (1), a fractionation tower feed pipeline (2) being arranged on one side of the fractionation tower (1), an air cooler (4) being connected to the top of the fractionation tower (1) via a tower top gas phase pipeline (3), the air cooler (4) being connected to a water cooler (6) via a first pipeline (5), the water cooler (6) being connected to a reflux tank (8) via a second pipeline (7), the reflux tank (8) The top of the tank is connected to a non-condensable steam pipeline (9), the bottom of the reflux tank (8) is connected to a reflux pump (11) via a third pipeline (10), the reflux pump (11) is connected to a reflux pipeline (12) and a tower top product pipeline (13), the other end of the reflux pipeline (12) is connected to the top of the fractionation tower (1), and the bottom of the fractionation tower (1) is connected to a first reboiler (16) via a fourth pipeline (14) and a fifth pipeline (15); It is characterized in that The tower top gas phase pipeline (3) is connected to an evaporator (17), the evaporator (17) is connected to a compressor suction tank (19) via a sixth pipeline (18), the top of the compressor suction tank (19) is connected to a compressor (21) via a seventh pipeline (20), the bottom of the compressor suction tank (19) is connected to an eighth pipeline (22), the compressor (21) is connected to a second reboiler (24) via a ninth pipeline (23), the second reboiler (24) is connected to the bottom of the fractionation tower (1) via a tenth pipeline (25) and an eleventh pipeline (26), one side of the second reboiler (24) is connected to a throttle valve (28) via a twelfth pipeline (27), and a thirteenth pipeline (29) is connected between the throttle valve (28) and the evaporator (17).

2. A phase-change self-circulating waste heat heat pump coupled distillation system according to claim 1, characterized in that: The heat source of the first reboiler (16) is low-pressure steam (30), and the first reboiler (16) is connected to a steam condensate pipeline (31).

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