Refrigerating and heating coupling system for ethyl acetate recovery

Abstract

The invention discloses a refrigerating and heating coupling system for ethyl acetate recovery, which relates to the technical field of heat pump energy conservation, is used for recovering ethyl acetate in the preparation process of lycopene oleoresin, and comprises a heat pump system (1), a refrigerating system (2), a solvent evaporator (5), a solvent condenser (6) and a heat exchanger (3), and a refrigeration evaporator (201) and a refrigeration condenser (202) are arranged in the refrigeration system. And the heat pump system and the refrigerating system are subjected to heat exchange, so that the effects of saving energy and reducing cost are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of ethyl acetate recovery, in particular to a refrigeration and heating coupling system for ethyl acetate recovery. Background Art

[0002] The production process of extracting oleoresin from tomatoes is as follows: adding solvent ethyl acetate to tomato paste, extracting at 50-60°C for a period of time, concentrating and crystallizing the extract, and then desolventizing. The crystals after desolventizing are further treated to finally prepare lycopene oleoresin. The solvent ethyl acetate after desolventizing must be recovered and then used to extract tomato paste, thus realizing the recycling of solvents and saving energy and protecting the environment.

[0003] The main process of ethyl acetate recovery is to heat it first to achieve vaporization, and then condense and liquefy the vaporized steam to achieve high-purity recovery. At present, the heating and condensing process in the ethyl acetate recovery process adopts a heating and cooling coupling system. China Patent Document Publication No. CN104534741A discloses a high-temperature heat pump and refrigerator heat efficient coupling energy-saving system for distillation equipment, which consists of a high-temperature water source heat pump, a water-cooled refrigerator, a coupling heat exchanger, an air energy heat exchanger, a waste heat recovery device, and a circulating pump. The hot water flowing out of the refrigerator condenser and the low-temperature water flowing out of the high-temperature heat pump evaporator are independently exchanged through the same heat exchanger for efficient heat coupling. During the heat coupling process, the high-temperature heat pump and the refrigerator exchange energy efficiently and complement each other, and then return to the condenser of the refrigerator and the evaporator of the high-temperature heat pump respectively, each of which obtains the best quality heat source, and the energy efficiency ratio is significantly improved. However, based on the further improvement of the current demand of enterprises for energy conservation and environmental protection, the existing coupling system can no longer meet the demand. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a refrigeration and heating coupling system for ethyl acetate recovery in view of the deficiencies in the prior art, which achieves energy saving and cost reduction by exchanging heat between the heat pump system and the refrigeration system therein.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A refrigeration and heating coupling system for ethyl acetate recovery comprises a heat pump system, a refrigeration system, a solvent evaporator, a solvent condenser and a heat exchanger, wherein the heat pump system is provided with a heat pump evaporator and a heat pump condenser, and the refrigeration system is provided with a refrigeration evaporator and a refrigeration condenser; The returned hot water flowing out of the solvent evaporator enters the heat pump condenser, and the heated hot water enters the solvent evaporator. The low-temperature water flowing out of the heat pump evaporator enters the heat exchanger, and the heated water after heat exchange in the heat exchanger returns to the heat pump evaporator. The return cold water flowing out of the solvent condenser enters the refrigeration evaporator, and the cooled cold water continues to enter the solvent condenser. The high-temperature water flowing out of the refrigeration condenser returns to the refrigeration condenser after heat exchange in the heat exchanger.

[0006] Furthermore, the heat pump system is a two-stage cycle heat pump system, the primary cycle includes a heat pump evaporator, a heat pump compressor 1 and a heat pump throttle valve 1, the secondary cycle includes a heat pump condenser, a heat pump compressor 2 and a heat pump throttle valve 2, and the primary cycle and the secondary cycle share a composite heat exchanger.

[0007] Furthermore, the refrigeration system includes a refrigeration evaporator, a refrigeration condenser, a refrigeration compressor and a refrigeration throttle valve.

[0008] Furthermore, the high-temperature water flowing out of the refrigeration condenser is split by the splitter, one part enters the heat exchanger for heat exchange, the other part enters the air cooler for cooling, and then flows into the mixer and returns to the refrigeration condenser.

[0009] Furthermore, the heat exchanger is an intermediate water tank, including a water tank with a built-in coil. Both sides of the water tank are respectively connected to the water inlet and outlet of the heat pump evaporator, and both ends of the coil are respectively connected to the water inlet and outlet of the refrigeration condenser.

[0010] Furthermore, the heat pump evaporator acts as a heat exchanger, and the high-temperature water flowing out of the refrigeration condenser is split through a splitter, one path enters the heat exchanger for heat exchange, and the other path is cooled by an air cooler, and then mixed in a mixer and returned to the refrigeration condenser.

[0011] Furthermore, the heat pump system is a primary circulation heat pump system, and the heat pump evaporator serves as a heat exchanger, wherein the heat pump system includes a heat exchanger, a heat pump condenser, a second heat pump compressor and a second heat pump throttle valve; the refrigeration system includes a refrigeration evaporator, a heat exchanger, a refrigeration compressor and a refrigeration throttle valve.

[0012] Furthermore, the refrigerant in the heat pump system circulates through the second heat pump throttle valve, the heat exchanger, the second heat pump compressor and the heat pump condenser in sequence; the refrigerant in the refrigeration system circulates through the refrigeration evaporator, the refrigeration compressor, the heat exchanger and the refrigeration throttle valve in sequence, and an air cooler is arranged between the heat exchanger and the refrigeration throttle valve.

[0013] The beneficial effects of the present invention are: 1. The present invention discloses a refrigeration and heating coupling system for ethyl acetate recovery, which makes full use of the energy of the system and exchanges the heat of the heat pump system and the refrigeration system by means of intermediate heat exchange of a heat exchanger, so that both the heat pump evaporator and the refrigeration condenser can obtain the best heat source, thereby making the heat pump system and the refrigeration system always in a high energy efficiency state. It is used for ethyl acetate solvent recovery, does not require additional energy supply, does not generate energy waste, and the entire system cycle is stable and energy-saving and environmentally friendly.

[0014] 2. The present invention provides three modes of coupling systems. The first mode heat pump system is a two-stage circulation heat pump system. The cold water generated by the heat pump evaporator of the heat pump system and the hot water generated by the refrigeration condenser of the refrigeration system realize heat energy coupling exchange in the water tank. The whole system has strong stability and can operate for a long time, achieving the purpose of energy saving and environmental protection.

[0015] 3. Based on the fact that the first mode has a large number of heat exchange coupling times, a second mode was developed, in which the heat pump evaporator is directly used as an intermediate heat exchanger, that is, the heat exchanger serves as the evaporator of the heat pump system on the one hand, and also as a heat exchanger for heat exchange with the refrigeration system. The water tank heat exchange mode is still adopted, and the water tank is equipped with a refrigeration condenser water inlet and outlet to exchange heat with the heat pump system evaporator. Compared with the first mode, the hot water of the refrigeration system is directly supplied to the heat pump system, which can improve efficiency and reduce the use of equipment.

[0016] When this mode is used, when the temperature of the intermediate water tank is 30°C, the pressure entering the heat pump compressor 1 is increased to 6 bar, and the outlet pressure of the refrigeration compressor is reduced to 12 bar, which can meet the requirements of the solvent evaporation and condensation process. This mode further simplifies the process, reduces the use of pumps, and greatly reduces power consumption.

[0017] 4. The third mode: the heat exchanger in this mode serves as both the evaporator of the heat pump system and the condenser of the refrigeration system. It also uses a water tank for heat exchange, which has high stability. Compared with the heat exchange system in the first mode, the entire process only uses a two-stage heat pump system, the equipment and process are further simplified, and the power consumption is further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a specific implementation of Example 1; Figure 3 Aspen simulation flow chart of Example 1; Figure 4 is a flow chart of Example 2; Figure 5 Aspen simulation flow chart of Example 2; Figure 6 is a schematic structural diagram of the heat exchanger in Example 2; Figure 7 is a flow chart of Example 3; Figure 8 is a schematic diagram of the structure of the heat exchanger in Example 3; Fig. 9 This is the Aspen simulation flow chart of Example 3.

[0019] In the figure: 1-heat pump system, 101-heat pump evaporator, 102-heat pump condenser, 103-heat pump compressor 1, 104-heat pump throttle valve 1, 105 heat pump compressor 2, 106 heat pump throttle valve 2, 107 composite heat exchanger. 2-refrigeration system, 201-cold evaporator, 202-refrigeration condenser, 203-refrigeration compressor, 204-refrigeration throttle valve, 3-heat exchanger, 301-water tank, 302-coil, 4-hot water tank, 5-solvent evaporator, 6-solvent condenser, 7 splitter, 8-air cooler, 9-mixer, 10-cold water tank. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. Example 1

[0021] The coupling system developed in the present application is mainly used for the recovery process of ethyl acetate in the preparation process of lycopene oleoresin, wherein the recovery of ethyl acetate adopts a solvent evaporator 5 to vaporize the solvent, and then the vaporized steam enters the solvent condenser 6 for condensation and liquefaction to achieve high-purity recovery, wherein the hot water and cold water required by the solvent evaporator 5 and the solvent condenser 6 are provided by the refrigeration and heating coupling system.

[0022] The refrigeration and heating coupling system for ethyl acetate recovery provided in this application is shown in Figure 1 and Figure 2 , including a heat pump system 1, a refrigeration system 2, a solvent evaporator 5, a solvent condenser 6 and a heat exchanger 3.

[0023] The heat pump system 1 is provided with a heat pump evaporator 101 and a heat pump condenser 102 , and the refrigeration system 2 is provided with a refrigeration evaporator 201 and a refrigeration condenser 202 .

[0024] The return hot water flowing out of the solvent evaporator 5 enters the heat pump condenser 102, and the heated hot water enters the solvent evaporator 5. The return cold water flowing out of the solvent condenser 6 enters the refrigeration evaporator 201, and the cooled cold water continues to enter the solvent condenser 6.

[0025] The low-temperature water flowing out of the heat pump evaporator 101 enters the heat exchanger 3, and the heated water after heat exchange in the heat exchanger 3 returns to the heat pump evaporator 101; the high-temperature water flowing out of the refrigeration condenser 202 returns to the refrigeration condenser 202 after heat exchange in the heat exchanger 3.

[0026] The heat pump system 1 in this embodiment is a two-stage circulation heat pump system. The primary circulation includes a heat pump evaporator 101, a heat pump compressor 1 103 and a heat pump throttle valve 1 104, and the secondary circulation includes a heat pump condenser 102, a heat pump compressor 2 105 and a heat pump throttle valve 2 106. The primary circulation and the secondary circulation share a composite heat exchanger 107. The structure of the composite heat exchanger is shown in Figure 8As shown, the difference is that in this embodiment, the left side is a secondary circulation evaporator, and the right side is a primary circulation condenser, and heat exchange is realized in the water tank. The two-stage circulation shares a heat exchanger, which can reduce the circulation pressure ratio and improve the energy efficiency of the air source heat pump. The primary circulation adopts medium-temperature refrigerant (type: R134), and the secondary circulation adopts high-temperature refrigerant (type: 142b). The high-temperature refrigerant is compressed and pressurized by the heat pump compressor 105, enters the heat pump condenser 102 to release heat, so that the 67°C return hot water flowing out of the solvent evaporator 5 is heated to 73°C and enters the solvent evaporator 5 again. The hot water can also be stored in the hot water tank 4 for circulation as needed.

[0027] The refrigeration system 2 includes a refrigeration evaporator 201, a refrigeration condenser 202, a refrigeration compressor 203 and a refrigeration throttle valve 204, wherein the refrigeration refrigerant evaporates and absorbs heat in the refrigeration evaporator 201, so that the -6°C return cold water refluxed from the solvent condenser 6 is cooled to -3°C, can be stored in the cold water tank 10, and then continue to enter the solvent condenser 6 to realize the ethyl acetate recovery cycle.

[0028] At the same time, the condensed water flowing out of the heat pump evaporator 101 of the heat pump system 1 and the high-temperature water flowing out of the refrigeration condenser 202 of the refrigeration system 2 undergo heat exchange in the heat exchanger 3 and then return to the heat pump evaporator 101 and the refrigeration condenser 202 respectively.

[0029] The specific structure of the heat exchanger 3 in this embodiment is an intermediate water tank, including a water tank 301, and the water tank 301 has a built-in coil 302, wherein the 15°C condensed water flowing out of the heat pump evaporator 101 enters the water tank 301, and after heat exchange with the water in the coil 302, the temperature is increased to 25°C and then returns to the heat pump evaporator 101 from the bottom of the water tank, while half of the 33°C high-temperature water flowing out of the refrigeration condenser 202 is diverted by the diverter 7 and enters the air cooler 8 to be cooled to 28°C, and the other half enters the inlet of the coil 302 in the water tank 301, exchanges heat with the water in the water tank 301 and is cooled to 31°C, and then flows out from the outlet of the coil 302. After the two paths are merged into the mixer 9, the water temperature is 30°C and returns to the refrigeration condenser 202.

[0030] The present application arranges a heat exchanger 3 to raise the temperature of the water flowing out of the heat pump evaporator 101 from 15°C to 25°C and returns, and to exchange the temperature of the water flowing out of the refrigeration condenser 202 from 33°C to 30°C and returns to the refrigeration condenser 202. The heat exchanger 3 enables both the heat pump evaporator 101 and the refrigeration condenser 202 to obtain the best heat source, so that the heat pump system and the refrigeration system are always in a high-efficiency state, without the need for additional energy supply, and energy-saving and environmentally friendly.

[0031] The operation process of Example 1 was simulated by Aspen simulation, and the simulation results are shown in Figure 3As shown, an intermediate water tank is used for heat exchange, with a heating capacity of 130 kW, a cooling capacity of 115 kW, a heating power of 37 kW, and a cooling power of 28 kW. Example 2

[0032] The intermediate water tank in Example 1 is actually a heat exchanger. The hot water (33°C) from the refrigeration system exchanges heat with the cold water (15°C) from the heating system. The hot water returning to the refrigeration system is cooled to 30°C, and the cold water returning to the heating system is heated to 25°C. However, the heating system wants the temperature at its low temperature end to be as high as possible, while the refrigeration cycle wants the temperature at its high temperature end to be as low as possible. If the intermediate water tank is not in the heat exchange operation mode, but the hot water from the refrigeration system is directly supplied to the heating cycle, the efficiency can be improved. Therefore, see Figure 4 As shown, the intermediate water tank is removed, and the heat pump evaporator 101 is directly used as the heat exchanger 3, which serves as the evaporator of the heat pump system and also as the heat exchanger for heat exchange with the refrigeration system. For the specific simulation process flow, see Figure 5 : The high-temperature water of 28°C flowing out of the refrigeration condenser 202 is split by the splitter 7, half of which enters the heat pump evaporator 101 and is heat-exchanged to 26°C. The other part is cooled to 20°C by the air cooler 8, mixed to 25°C in the mixer 9 and returns to the refrigeration condenser 202.

[0033] The structural diagram of the heat exchanger 3 in this embodiment is shown in FIG. Figure 6 , including a water tank 301, the left side of which serves as an evaporator of the heat pump system, and the heat pump system refrigerant circulates inside. The water tank 301 is provided with a refrigeration condenser water inlet and outlet, which can heat the high-temperature water flowing out of the refrigeration condenser 202 into low-temperature water.

[0034] from Figure 5 It can be seen from the simulation data that Example 2 subtracts the intermediate water tank compared to Example 1, and the heat pump evaporator 101 is used as the heat exchanger 3. The energy consumption of the heating compressor is reduced from 37kW to 33kW, the energy consumption of the refrigeration compressor is reduced from 28kW to 23kW, and the heat exchange capacity of the air cooler is reduced from -50kW to -41kW. Compared with the system with the intermediate water tank, the system after eliminating the intermediate water tank consumes 15% less power. Example 3

[0035] The heat pump system 1 in Example 3 is a primary circulation heat pump system, see Figure 7 As shown, the heat pump evaporator 101 serves as the heat exchanger 3, that is, as the evaporator 101 of the heat pump system, and also as the condenser 202 of the refrigeration system, a three-in-one hybrid heat exchanger, wherein the heat pump system includes the heat exchanger 3 (heat pump evaporator 101 / refrigeration condenser 202), the heat pump condenser 102, the heat pump compressor 105 and the heat pump throttle valve 106.

[0036] The refrigeration system 2 includes a refrigeration evaporator 201 , a heat exchanger 3 (refrigeration condenser 202 ), a refrigeration compressor 203 and a refrigeration throttle valve 204 .

[0037] The specific structure of the heat exchanger 3 is shown in Figure 8 The water tank 301 is included. The water temperature in the water tank 301 is 30-40° C. The evaporator of the heat pump system and the condenser of the refrigeration system realize heat exchange in the water tank 301 .

[0038] from Fig. 9 It can be seen from the simulation data that the refrigerant temperature at the inlet and outlet of the refrigeration condenser of the refrigeration system is 62~39℃, while the evaporator temperature of the heating system is 35℃. If the pressure is adjusted appropriately, the two can form a temperature difference and directly exchange heat, that is, the two-stage heat pump of this embodiment can achieve the purpose of cooling and heating.

[0039] Fig. 9 The refrigerant pressure of the refrigeration cycle is not changed, so the refrigeration power remains unchanged, but the energy consumption of the heating compressor can be reduced to 21kW. At the same time, a large amount of equipment is saved. Compared with the heat exchange of the intermediate water tank, the power consumption is reduced by 26%.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A refrigeration and heating coupling system for ethyl acetate recovery, characterized in that: The invention comprises a heat pump system (1), a refrigeration system (2), a solvent evaporator (5), a solvent condenser (6) and a heat exchanger (3), wherein the heat pump system (1) is provided with a heat pump evaporator (101) and a heat pump condenser (102), and the refrigeration system is provided with a refrigeration evaporator (201) and a refrigeration condenser (202); The returned hot water flowing out of the solvent evaporator (5) enters the heat pump condenser (102), the heated hot water enters the solvent evaporator (5), the low-temperature water flowing out of the heat pump evaporator (101) enters the heat exchanger (3), and the heated water after heat exchange in the heat exchanger (3) returns to the heat pump evaporator (101); The return cold water flowing out of the solvent condenser (6) enters the refrigeration evaporator (201), and the cooled cold water continues to enter the solvent condenser (6). The high-temperature water flowing out of the refrigeration condenser (202) returns to the refrigeration condenser (202) after heat exchange in the heat exchanger (3).

2. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The heat pump system (1) is a two-stage circulation heat pump system, wherein the first-stage circulation comprises a heat pump evaporator (101), a heat pump compressor 1 (103) and a heat pump throttle valve 1 (104), and the second-stage circulation comprises a heat pump condenser (102), a heat pump compressor 2 (105) and a heat pump throttle valve 2 (106), and the first-stage circulation and the second-stage circulation share a composite heat exchanger (107).

3. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The refrigeration system (2) comprises a refrigeration evaporator (201), a refrigeration condenser (202), a refrigeration compressor (203) and a refrigeration throttle valve (204).

4. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The high-temperature water flowing out of the refrigeration condenser (202) is split by the splitter (7), with one part entering the heat exchanger (3) for heat exchange, and the other part entering the air cooler (8) for temperature reduction, and then entering the mixer (9) and returning to the refrigeration condenser (202).

5. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The heat exchanger (3) is an intermediate water tank, comprising a water tank (301). The water tank (301) has a built-in coil (302). Both sides of the water tank (301) are respectively connected to the water inlet and the water outlet of the heat pump evaporator (101), and both ends of the coil (302) are respectively connected to the water inlet and the water outlet of the refrigeration condenser (202).

6. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The heat pump evaporator (101) serves as a heat exchanger (3). The high-temperature water flowing out of the refrigeration condenser (202) is split by a splitter (7), one path entering the heat exchanger (3) for heat exchange, and the other path passing through an air cooler (8) for cooling. The water is then mixed in a mixer (9) and returned to the refrigeration condenser (202).

7. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 1, characterized in that: The heat pump system (1) is a primary circulation heat pump system, wherein the heat pump evaporator (101) serves as a heat exchanger (3), wherein the heat pump system comprises a heat exchanger (3), a heat pump condenser (102), a second heat pump compressor (105) and a second heat pump throttle valve (106); and the refrigeration system (2) comprises a refrigeration evaporator (201), a heat exchanger (3), a refrigeration compressor (203) and a refrigeration throttle valve (204).

8. The refrigeration and heating coupling system for ethyl acetate recovery according to claim 7, characterized in that: The refrigerant in the heat pump system (1) is circulated through the second heat pump throttle valve (106), the heat exchanger (3), the second heat pump compressor (105) and the heat pump condenser (102) in sequence; the refrigerant in the refrigeration system (2) is circulated through the refrigeration evaporator (201), the refrigeration compressor (203), the heat exchanger (3) and the refrigeration throttle valve (204) in sequence, and an air cooler (8) is arranged between the heat exchanger (3) and the refrigeration throttle valve (204).

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