Organic solvent recovery equipment

Abstract

The invention discloses organic solvent recovery equipment, which belongs to the technical field of organic solvent recovery, and comprises an organic solvent gas phase separation system, which comprises a heater and an evaporation chamber, the inlet end of the heater is communicated with a liquid inlet pipe, and the outlet end of the heater is communicated with the evaporation chamber; the condensation recovery system comprises a condenser and a storage tank, the inlet end of the condenser is communicated with the evaporation chamber, and the outlet end of the condenser is communicated with the storage tank; the heat pump system comprises a heat pump circulating compressor and a heat balance heat exchanger, the heat pump circulating compressor conveys a refrigerant into the heater to exchange heat with the organic solvent in the heater, the refrigerant enters the heat balance heat exchanger, and the heat balance heat exchanger is communicated with a pressure reducing valve; and the vacuum pump is communicated with the storage tank. According to the recycling equipment, the heat pump system is adopted, in the circulating process of the refrigerant in the system, the heat release-heat absorption process is conducted through pressure change and circulation, an external heat source and an external cold source do not need to be provided, the operation cost is reduced, and the recycling efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of organic solvent recovery, in particular to an organic solvent recovery device. Background Art

[0002] Organic solvents are a large class of organic compounds that are widely used in life and production. Organic solvents can dissolve some compounds that are insoluble in water, so they are usually used in industrial production. Most organic solvents are flammable, corrosive, volatile and biotoxic, and are classified as a type of hazardous waste. At present, there are more than 3,000 kinds of organic solvents in normal use, which are widely used in the fields of chemical industry, medicine, printing, textile, etc. Commonly used substances such as benzene, toluene, chloroalkanes, etc. are all strong carcinogens.

[0003] In industrial production, especially in chemical production, various organic solvents are used and mixed in production wastewater. Such wastewater is harmful to the environment, difficult to treat, and has high treatment costs. Recycling organic solvents in wastewater is one of the important ways to solve urban waste particles, protect and improve the environment, achieve sustainable development, and establish a resource-saving society. Therefore, recycling and recycling various organic solvent wastewaters generated in the production process of enterprises can improve the comprehensive utilization level of hazardous wastes and bring good social and environmental benefits.

[0004] The equipment currently used for organic solvent recovery is various distillation towers. Such equipment uses steam and electricity as the heat source of the equipment and circulating cooling water as the cold source of the equipment. Such equipment generally has the characteristics of large equipment investment and high operating energy consumption. Especially when used to treat wastewater with low organic solvent content and large content fluctuations, the equipment has poor operating stability and low recovery rate. Summary of the invention

[0005] In order to solve the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide an organic solvent recovery device, the device structure is greatly simplified, and the equipment cost is reduced. The device adopts a heat pump system. During the circulation of the refrigerant in the system, the pressure changes and the heat release-endothermic process is circulated. There is no need to provide an external heat source or cold source, which reduces the operating cost and improves the recovery efficiency of the organic solvent.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] Provided is an organic solvent recovery device, comprising:

[0008] An organic solvent gas phase separation system comprises a heater and an evaporation chamber, wherein the inlet end of the heater is connected to a liquid inlet pipe, and the outlet end is connected to the evaporation chamber, and the organic solvent enters the evaporation chamber after being heated in the heater;

[0009] A condensation recovery system, comprising a condenser and a storage tank, wherein the inlet end of the condenser is connected to the evaporation chamber, and the outlet end is connected to the storage tank;

[0010] A heat pump system, comprising a heat pump circulation compressor and a heat balance heat exchanger, wherein the heat pump circulation compressor delivers a refrigerant to a heater to perform heat exchange with an organic solvent in the heater, and the refrigerant enters the heat balance heat exchanger, which is connected to a pressure reducing valve, and the refrigerant flows from the pressure reducing valve into an evaporation chamber and a condenser to cool the solvent in the evaporation chamber and the condenser, and then the liquid is stored in the storage tank;

[0011] A vacuum pump is connected to the storage tank and is used to provide a vacuum environment for the organic solvent gas phase separation system and the condensation recovery system.

[0012] Furthermore, the heater and the evaporation chamber are both provided with an organic solvent recovery chamber and a refrigerant circulation chamber.

[0013] Furthermore, the evaporation chamber includes a sprayer, which is connected to the organic solvent recovery chamber of the heater. The organic solvent is sprayed out from the sprayer and evaporates after heat exchange with the refrigerant.

[0014] Furthermore, the evaporation chamber also includes a precooler located above the sprayer, the inlet end of the precooler is connected to the pressure reducing valve, and the outlet end is connected to the heat pump circulation compressor; the refrigerant circulation cavity is located in the precooler.

[0015] Furthermore, the precooler is fitted with the body wall of the evaporator, and the precooler is provided with a flow opening which passes through from top to bottom, and the cavity structure outside the flow opening forms a refrigerant flow cavity.

[0016] Furthermore, the evaporation chamber is located below the sprayer and is a liquid storage chamber.

[0017] Furthermore, it also includes a circulation pump, wherein the inlet end of the circulation pump is connected to the evaporation chamber, and the outlet end of the circulation pump is connected to the liquid inlet pipe and the liquid discharge pipe respectively.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The organic solvent recovery equipment of the present invention adopts a heat pump system. During the circulation of the refrigerant in the system, the refrigerant undergoes a heat release-absorption process through pressure changes. The refrigerant absorbs the phase change heat of the gaseous organic solvent and serves as a heat source for the evaporation of the organic solvent without providing an external heat source. At the same time, the refrigerant is decompressed by a pressure reducing valve, and the refrigerant absorbs heat through phase change, serving as a cold source for the condensation of the organic solvent without providing an external cold source. The equipment structure is simplified and the energy consumption is low.

[0020] 2. The organic solvent recovery equipment exemplified in the present invention has a simple evaporation chamber structure, a low system pressure drop, a high vacuum degree in the evaporation chamber, and a small pressure difference at each position in the evaporation chamber, which can effectively improve the separation efficiency of the organic solvent;

[0021] 3. In the organic solvent recovery equipment of the present invention, a low-temperature refrigerant is passed through the precooler, and the temperature of the organic solvent gas is continuously reduced during the process of passing through the precooler, so that the purity of the gaseous organic solvent is continuously improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 is a cross-sectional view of the evaporation chamber;

[0025] Figure 3 For the schematic diagram.

[0026] In the figure: 1-liquid inlet pipe, 2-heater, 3-evaporation chamber, 4-vacuum pump, 5-circulation pump, 6-liquid discharge pipe, 7-condenser, 8-storage tank, 9-heat balance heat exchanger, 10-pressure reducing valve, 11-heat pump circulation compressor, 31-sprinkler, 32-precooler, 33-liquid storage chamber, 34-circulation port. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] like Figure 1 As shown, this embodiment provides an organic solvent recovery device, including an organic solvent gas phase separation system, a condensation recovery system and a heat pump system. The organic solvent forms gas or water vapor in the organic solvent gas phase separation system and is recovered in the condensation recovery system; the refrigerant circulates in the heat pump system as a heat source and a cold source for recovering the organic solvent.

[0030] Specifically, the organic solvent gas phase separation system includes a heater 2 and an evaporation chamber 3, wherein the heater 2 and the evaporation chamber 3 are both provided with an organic solvent recovery chamber and a refrigerant circulation chamber, one end of the organic solvent recovery chamber of the heater 2 is connected to the liquid inlet pipe 1, and the other end is connected to the evaporation chamber 3, the organic solvent flows into the heater 2 from the liquid inlet pipe 1, and evaporates in the evaporation chamber 3 to form gas or water vapor.

[0031] The organic solvent gas phase separation system also includes a vacuum pump 4, which is connected to a storage tank 8 to provide a high vacuum environment for the heater 2 and the organic solvent recovery chamber in the evaporation chamber 3. The evaporation chamber 3 has a simple structure, a low system pressure drop, a high vacuum degree in the evaporation chamber 3, and a small pressure difference at each position in the evaporation chamber 3, which can effectively improve the separation efficiency of the organic solvent.

[0032] The condensation recovery system includes a condenser 7 and a storage tank 8. The condenser 7 is provided with an organic solvent recovery chamber and a refrigerant circulation chamber, and the inlet end of the organic solvent recovery chamber is connected to the upper end of the evaporation chamber 3, and the outlet end is connected to the storage tank 8. The evaporated organic solvent gas or water vapor is condensed in the condenser 7 to form a liquid that flows into the storage tank 8.

[0033] The condenser 7 and storage tank 8 of the condensation recovery system are provided with a high vacuum environment by the vacuum pump 4. The condenser 7 recovers system heat in the process of cooling and condensing the organic solvent, and exchanges the heat with the refrigerant. In the next refrigerant cycle, this part of the heat is used for the heating process of the organic solvent wastewater through the heater 2 of the gas phase separation system. The storage tank 8 temporarily stores the recovered liquid organic solvent and transports it to the outside of the equipment at an appropriate time.

[0034] The heat pump system includes a heat pump circulation compressor 11, which transports the refrigerant to the refrigerant circulation cavity of the heater 2, and flows out from the heater 2 to the heat balance heat exchanger 9. The heat balance heat exchanger 9 is connected to a pressure reducing valve 10, and the outlet ends of the pressure reducing valve 10 are respectively connected to the refrigerant circulation cavities of the evaporation chamber 3 and the condenser 7. The refrigerant flows through the evaporation chamber 3 and the condenser 7 and then flows into the heat pump circulation compressor 11.

[0035] In this embodiment, Figure 2As shown, the evaporation chamber 3 includes a sprayer 31, which is connected to the outlet end of the organic solvent recovery chamber of the heater 2; a precooler 32 is provided above the sprayer 31, the inlet end of the precooler 32 is connected to the outlet end of the pressure reducing valve 10, and the outlet end is connected to the inlet end of the heat pump circulation compressor 11; a liquid storage chamber 33 is provided below the sprayer 31. The precooler 32 is provided with a flow port 34 that runs through from top to bottom, and the gas or water vapor formed by evaporation flows upward through the flow port 34. The precooler 32 is filled with a low-temperature refrigerant, and the organic solvent gas is continuously cooled during the process of passing through the precooler 32, so that the purity of the gaseous organic solvent is continuously improved.

[0036] The heater 2, heat balance heat exchanger 9, condenser 7, etc. are all existing technologies and will not be described in detail here.

[0037] Working principle:

[0038] like Figure 3 As shown, the heat pump system is filled with refrigerant, and the refrigerant is circulated in the heat pump system under the drive of the heat pump circulation compressor 11. At the outlet of the heat pump circulation compressor 11, the refrigerant is a high-temperature, high-pressure gas. The high-temperature, high-pressure gas flows through the heater 2 of the organic solvent gas phase separation system through the pipeline, and releases heat to the organic solvent-containing wastewater flowing through the heater 2, thereby increasing the temperature of the wastewater; the refrigerant after releasing heat changes into a low-temperature, high-pressure liquid, and the low-temperature, high-pressure liquid flows through the heat balance heat exchanger 9 through the pipeline, and exchanges heat with the external environment of the equipment according to the heat balance requirements of the heat pump system; the refrigerant after heat balance flows through the pressure reducing valve 10 through the pipeline, and the refrigerant pressure is reduced to become a low-temperature, low-pressure liquid; the refrigerant after decompression flows through the condenser 7 and the precooler 32 of the evaporation chamber 3 through the pipeline, respectively, and absorbs heat and cools the gas phase organic solvent flowing through the condenser 7 and the precooler 32; the refrigerant after absorbing heat changes into a low-temperature, low-pressure gas, and the low-temperature, low-pressure gas flows to the inlet of the heat pump system compressor through the pipeline. After the refrigerant is compressed in the compressor, its volume decreases, and its pressure and temperature rise. The high-temperature, high-pressure gas refrigerant is discharged through the compressor outlet, completing a heat-cooling cycle.

[0039] A high vacuum environment is provided by a vacuum pump 4 in the heater 2 and the evaporation chamber 3 of the organic solvent gas phase separation system. The wastewater containing organic solvents enters the heater 2 of the organic solvent gas phase separation system, and is heated after heat exchange with the refrigerant; the heated organic solvent wastewater enters the sprayer 31 of the evaporation chamber 3 and is sprayed into the evaporation chamber 3. For low-boiling point organic solvents, most of the organic solvents are volatilized into gases during the spraying into the liquid storage chamber 33. After being cooled by the precooler 32, they enter the condenser 7 of the condensation recovery system; the organic solvent gas is cooled after heat exchange with the refrigerant in the condenser 7, and the cooled organic solvent changes phase into liquid and flows into the storage tank 8; the wastewater sprayed into the evaporation chamber 3 falls into the liquid storage chamber 33, and there is still a small amount of organic solvent that has not volatilized into gas phase in the wastewater. This part of the wastewater is sent to the heater 2 again by the circulating pump 5 for heating and temperature rise, and multiple volatilizations are performed, which can greatly improve the recovery rate of the organic solvent; after multiple circulations, the organic solvent concentration in the liquid storage chamber 33 is reduced to the set value, and the wastewater is transported to the outside of the equipment through the circulating pump 5. For high-boiling-point organic solvents, during the process of being sprayed into the liquid storage chamber 33, most of the water evaporates into water vapor, and after being cooled by the precooler 32, it enters the condenser 7 of the condensation recovery system; the water vapor exchanges heat with the refrigerant in the condenser 7 to cool down, and the cooled water vapor changes into liquid and flows into the storage tank 8; the organic solvent entering the liquid storage chamber 33 still has a small amount of water that has not volatilized into the gas phase, and this part of the organic solvent is then heated and heated by the heater 2, and volatilized multiple times, which can greatly improve the purity of the organic solvent; after the purity of the organic solvent in the liquid storage chamber 33 reaches the set value, it is transported to the outside of the equipment through the circulation pump 5.

[0040] Taking toluene low-boiling point organic solvent wastewater as an example, first start the vacuum pump 4 to pump the organic solvent gas phase separation system and the condensation recovery system into a high vacuum state; the toluene wastewater enters the heater 2 through the liquid inlet pipe 1 at normal temperature and pressure, and is heated by the high-temperature and high-pressure refrigerant in the heater 2; then enters the sprayer 31 of the evaporation chamber 3 and is sprayed into the evaporation chamber 3. Since the evaporation chamber 3 is in a high vacuum state, most of the toluene in the toluene wastewater evaporates into gas during the spraying process, and at the same time, a small amount of wastewater also evaporates into gas; the mixed gas flows upward through the precooler 32, and in the process of flowing, it exchanges heat with the precooler 32 and then cools down. The water vapor in the mixed gas condenses into liquid and falls back into the liquid storage chamber 33. During this process, the cooling process is continuously carried out. Therefore, the water vapor continues to fall back and the purity of toluene in the gas continues to increase. The purified toluene gas enters the condenser 7. After heat exchange with the low-temperature refrigerant in the condenser 7, the toluene gas is cooled and liquefied. At the same time, the heat is exchanged to the refrigerant as heat energy for the evaporation of the next cycle of toluene wastewater. The liquefied toluene enters the storage tank 8. There is still unvolatile toluene in the wastewater entering the liquid storage chamber 33. This part of the wastewater is transported to the heater 2 through the circulating pump 5 and the heating-volatilization process is carried out again.

[0041] Taking NMP high-boiling point organic solvent wastewater as an example, first start the vacuum pump 4 to pump the organic solvent gas phase separation system and the condensation recovery system into a high vacuum state; the NMP wastewater enters the heater 2 through the liquid inlet pipe 1 at room temperature and pressure, and is heated by the high-temperature and high-pressure refrigerant in the heater 2; then enters the sprayer 31 of the evaporation chamber 3 and is sprayed into the evaporation chamber 3. Since the evaporation chamber 3 is in a high vacuum state, most of the water in the NMP wastewater evaporates into water vapor during the spraying process, and a small amount of NMP also evaporates into gas; the mixed gas flows upward through the precooler 32, and during the flow process, it exchanges heat with the precooler 32 and then drops to a low temperature. The NMP in the mixed gas is condensed into liquid and falls back into the liquid storage chamber 33. During this process, the cooling process continues, so the NMP continues to fall back and the purity of the water vapor in the gas continues to increase; the purified water vapor enters the condenser 7, and after heat exchange with the low-temperature refrigerant in the condenser 7, the water vapor is cooled and liquefied, and at the same time, the heat is exchanged to the refrigerant as heat energy for evaporation of NMP wastewater in the next cycle; the liquefied water vapor enters the storage tank 8; there is still unevaporated wastewater in the NMP entering the liquid storage chamber 33, and this part of the NMP is transported to the heater 2 through the circulating pump 5 to undergo the heating-volatilization process again.

[0042] Compared with the existing organic solvent recovery equipment, the organic solvent recovery equipment illustrated in the present embodiment does not require a heat source and a cold source to be provided outside the equipment; the heat required for the evaporation of the organic solvent comes from the phase change heat release when the gaseous organic solvent is condensed into a liquid state in the condenser 7 after separation, and is recovered and transferred through the refrigerant of the heat pump system; the cold required for the condensation of the organic solvent comes from the phase change heat absorption when the liquid organic solvent evaporates into a gaseous state during the evaporation of the organic solvent wastewater, and is recovered and transferred through the refrigerant of the heat pump system; since no external heat source and cold source are required, the operating cost of the equipment is much lower than that of the existing distillation tower organic solvent recovery equipment; in addition, the equipment structure is greatly simplified, so the equipment cost is lower than that of the existing solvent recovery equipment; and, since the internal structure is simplified, the internal vacuum degree of the gas phase separation system is high, which improves the recovery efficiency of the organic solvent, thereby further reducing the equipment cost and the operating cost.

[0043] Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An organic solvent recovery device, characterized in that: include: An organic solvent gas phase separation system comprises a heater (2) and an evaporation chamber (3), wherein the inlet end of the heater (2) is connected to a liquid inlet pipe (1), and the outlet end is connected to the evaporation chamber (3); the organic solvent enters the evaporation chamber (3) after being heated in the heater (2); A condensation recovery system, comprising a condenser (7) and a storage tank (8), wherein the inlet end of the condenser (7) is connected to the evaporation chamber (3), and the outlet end is connected to the storage tank (8); A heat pump system, comprising a heat pump circulation compressor (11) and a heat balance heat exchanger (9), wherein the heat pump circulation compressor (11) transports a refrigerant to a heater (2) to perform heat exchange with an organic solvent in the heater (2), and the refrigerant enters the heat balance heat exchanger (9), and the heat balance heat exchanger (9) is connected to a pressure reducing valve (10), and the refrigerant flows from the pressure reducing valve (10) into an evaporation chamber (3) and a condenser (7), thereby cooling the solvent in the evaporation chamber (3) and the condenser (7), and then the liquid is stored in the storage tank (8); A vacuum pump (4) is connected to the storage tank (8) and is used to provide a vacuum environment for the organic solvent gas phase separation system and the condensation recovery system.

2. An organic solvent recovery device according to claim 1, characterized in that: The heater (2) and the evaporation chamber (3) are both provided with an organic solvent recovery chamber and a refrigerant circulation chamber.

3. An organic solvent recovery device according to claim 2, characterized in that: The evaporation chamber (3) comprises a sprayer (31), the sprayer (31) being in communication with the organic solvent recovery chamber of the heater (2); the organic solvent is sprayed out of the sprayer (31) and evaporates after heat exchange with the refrigerant.

4. An organic solvent recovery device according to claim 3, characterized in that: The evaporation chamber (3) further comprises a precooler (32) located above the sprayer (31); the inlet end of the precooler (32) is connected to the pressure reducing valve (10), and the outlet end is connected to the heat pump circulation compressor (11); the refrigerant circulation cavity is located in the precooler (32).

5. An organic solvent recovery device according to claim 4, characterized in that: The precooler (32) is fitted with the body wall of the evaporator, and the precooler (32) is provided with a flow opening (34) penetrating from top to bottom, and the cavity structure outside the flow opening (34) forms a refrigerant flow cavity.

6. The organic solvent recovery equipment according to claim 3, characterized in that: The evaporation chamber (3) is located below the sprayer (31) and is a liquid storage chamber (33).

7. The organic solvent recovery device according to claim 1, characterized in that: It also comprises a circulation pump (5), the inlet end of the circulation pump (5) is connected to the evaporation chamber (3), and the outlet end is respectively connected to the liquid inlet pipe (1) and the liquid discharge pipe (6).

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