Refrigeration and heating coupled system for recovering ethyl acetate

Abstract

The application discloses a refrigeration and heating coupled system for recovering ethyl acetate, and relates to the technical field of heat pump energy saving, and is used for recovering ethyl acetate in a preparation process of lycopene oil resin, and comprises a heat pump system (1), a refrigeration system (2), a solvent evaporator (5), a solvent condenser (6) and a heat exchanger (3). The heat pump system (1) is internally provided with a heat pump evaporator (101) and a heat pump condenser (102), and the refrigeration system is internally provided with a refrigeration evaporator (201) and a refrigeration condenser (202). Heat exchange is performed on the heat pump system and the refrigeration system, so that the energy saving and cost reduction effects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ethyl acetate recovery, in particular to a refrigeration and heating coupled system for ethyl acetate recovery. BACKGROUND

[0002] The production process of extracting oil resin from tomatoes is as follows: adding solvent ethyl acetate in tomato paste, extracting for a period of time at 50-60 DEG C, and then concentrating and crystallizing the extracted liquid, and then desolventizing, and further processing the desolventized crystalline to finally prepare lycopene oil resin. The desolventized solvent ethyl acetate is recycled for extracting tomato paste, thereby achieving the recycling of the solvent, saving energy and protecting the environment.

[0003] The main process of ethyl acetate recovery is to first heat it to realize vaporization, and then condense and liquefy the vaporized steam to realize high-purity recovery. At present, the heating and condensing processes in the ethyl acetate recovery process adopt a heating and refrigeration coupled system. Chinese patent document No. CN104534741A discloses a high-temperature heat pump and refrigeration machine heat efficient coupling energy saving system of distillation equipment, which is composed of a high-temperature water source heat pump, a water-cooled refrigeration machine, a coupled heat exchanger, an air energy heat exchanger, a waste heat recovery device and a circulating pump. The hot water flowing out of the condenser of the refrigeration machine and the low-temperature water flowing out of the evaporator of the high-temperature heat pump are independently subjected to high-efficiency heat coupling exchange through the same heat exchanger. In the heat coupling process, the high-temperature heat pump and the refrigeration machine are subjected to high-efficiency energy exchange complementation, and then are respectively returned to the condenser of the refrigeration machine and the evaporator of the high-temperature heat pump, respectively, to obtain the best grade heat source, and the energy efficiency ratio is significantly improved. However, based on the further improvement of the demand of enterprises for energy saving and environmental protection, the existing coupled system cannot meet the demand. SUMMARY

[0004] Therefore, the present application aims at the deficiencies of the prior art, and provides a refrigeration and heating coupled system for ethyl acetate recovery, which realizes energy saving and cost reduction by heat exchange between the heat pump system and the refrigeration system.

[0005] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0006] The refrigeration and heating coupled system for ethyl acetate recovery comprises a heat pump system, a refrigeration system, a solvent evaporator, a solvent condenser and a heat exchanger, the heat pump system is internally provided with a heat pump evaporator and a heat pump condenser, and the refrigeration system is internally provided with a refrigeration evaporator and a refrigeration condenser.

[0007] The returned hot water flowing out of the solvent evaporator enters the heat pump condenser, 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.

[0008] The returned cold water from the solvent condenser enters the refrigeration evaporator, and the cooled cold water continues to enter the solvent condenser.

[0009] Further, the heat pump system is a two-stage circulation heat pump system, a first-stage circulation comprising a heat pump evaporator, a heat pump compressor one and a heat pump throttling valve one, and a second-stage circulation comprising a heat pump condenser, a heat pump compressor two and a heat pump throttling valve two, the first-stage circulation and the second-stage circulation sharing a composite heat exchanger.

[0010] Further, the refrigeration system comprises a refrigeration evaporator, a refrigeration condenser, a refrigeration compressor and a refrigeration throttling valve.

[0011] Further, the high-temperature water flowing out of the refrigeration condenser is divided by a flow divider, a part of which enters the heat exchanger for heat exchange, and another part of which enters the air cooler for cooling, and then is mixed in the mixer and returned to the refrigeration condenser.

[0012] Further, the heat exchanger is a middle water tank comprising a water tank, the water tank being internally provided with a coil pipe, the water tank being communicated with the water inlet and the water outlet of the heat pump evaporator at two sides respectively, and the coil pipe being communicated with the water inlet and the water outlet of the refrigeration condenser at two ends respectively.

[0013] Further, the heat pump evaporator serves as the heat exchanger, the high-temperature water flowing out of the refrigeration condenser is divided by the flow divider, one part of which enters the heat exchanger for heat exchange, and another part of which is cooled by the air cooler, and then is mixed in the mixer and returned to the refrigeration condenser.

[0014] Further, the heat pump system is a one-stage circulation heat pump system, and the heat pump evaporator serves as the heat exchanger, wherein the heat pump system comprises the heat exchanger, a heat pump condenser, a heat pump compressor two and a heat pump throttling valve two, and the refrigeration system comprises a refrigeration evaporator, the heat exchanger, a refrigeration compressor and a refrigeration throttling valve.

[0015] Further, the refrigerant in the heat pump system sequentially passes through the heat pump throttling valve two, the heat exchanger, the heat pump compressor two and the heat pump condenser to form a circulation, the refrigerant in the refrigeration system sequentially passes through the refrigeration evaporator, the refrigeration compressor, the heat exchanger and the refrigeration throttling valve to form a circulation, and the air cooler is arranged between the heat exchanger and the refrigeration throttling valve.

[0016] The present application has the following beneficial effects:

[0017] 1. The application discloses a refrigeration and heating coupled system for recovering ethyl acetate, which fully utilizes the energy of the system, exchanges the heat of the heat pump system and the refrigeration system by adopting the heat exchange mode of the heat exchanger, so that the heat pump evaporator and the refrigeration condenser can obtain the optimal heat source, thereby keeping the heat pump system and the refrigeration system in the high energy efficiency state, and the system is used for recovering ethyl acetate solvent, does not need additional energy supply, does not produce energy waste, and is high in circulation, stability, energy saving and environmental protection.

[0018] 2. The application provides three modes of coupled systems, the heat pump system of the first mode is a two-stage circulating 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 are coupled and exchanged in the water tank, the whole system is high in stability and can be operated for a long time, and the purpose of energy saving and environmental protection is achieved.

[0019] 3. Based on the fact that the heat exchange coupling times of the first mode are more, the second mode is developed, the heat pump evaporator is directly used as the heat exchanger for intermediate heat exchange, that is, the heat exchanger is used as the evaporator of the heat pump system and the heat exchanger for heat exchange with the refrigeration system, and the water tank heat exchange mode is still adopted, the water tank is provided with a refrigeration condenser water inlet and a refrigeration condenser water outlet, and heat exchange is carried out 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, so that the efficiency can be improved and the use of equipment can be reduced.

[0020] When the temperature of the intermediate water tank in the mode is 30 DEG C, the pressure of the heat pump compressor one is increased to 6 bar, and the outlet pressure of the refrigeration compressor is reduced to 12 bar, so that the requirements of the solvent evaporation and condensation process can be met, the process is further simplified, the use of pumps is reduced, and the power consumption is greatly reduced.

[0021] 4. The third mode, the heat exchanger of the mode is used as the evaporator of the heat pump system and the condenser of the refrigeration system, and the water tank heat exchange is still adopted, and the stability is high, compared with the heat exchange system of the first mode, the whole process only adopts a two-stage heat pump system, the equipment and the process are further simplified, and the power consumption is further reduced. DETAILED DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a flow chart of the embodiment 1 of the application;

[0023] Figure 2 It is a specific embodiment schematic view of the embodiment 1;

[0024] Figure 3 It is an Aspen simulation flow chart of the embodiment 1;

[0025] Figure 4 It is a flow chart of the embodiment 2;

[0026] Figure 5 Aspen simulation flow chart for Example 2;

[0027] Figure 6 Structural schematic diagram of heat exchanger in Example 2;

[0028] Figure 7 Flow chart for Example 3;

[0029] Figure 8 Structural schematic diagram of heat exchanger in Example 3;

[0030] Figure 9 Aspen simulation flow chart for Example 3.

[0031] In the figure: 1-heat pump system, 101-heat pump evaporator, 102-heat pump condenser, 103-heat pump compressor one, 104-heat pump throttling valve one, 105-heat pump compressor two, 106-heat pump throttling valve two, 107-complex heat exchanger. 2-refrigeration system, 201-refrigeration evaporator, 202-refrigeration condenser, 203-refrigeration compressor, 204-refrigeration throttling valve, 3-heat exchanger, 301-water tank, 302-coil pipe, 4-hot water tank, 5-solvent evaporator, 6-solvent condenser, 7-splitter, 8-air cooler, 9-mixer, 10-cold water tank. DETAILED DESCRIPTION

[0032] The application will be further described below in combination with the drawings and examples. Example 1

[0033] The coupling system developed in the application is mainly used for the recovery process of ethyl acetate in the preparation process of lycopene oil resin, wherein the ethyl acetate recovery adopts the solvent evaporator 5 to vaporize the solvent, and then the vaporized steam enters the solvent condenser 6 to be condensed and liquefied to realize 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.

[0034] The refrigeration and heating coupling system for ethyl acetate recovery provided in the application, see Figure 1 and Figure 2 , comprises a heat pump system 1, a refrigeration system 2, a solvent evaporator 5, a solvent condenser 6 and a heat exchanger 3.

[0035] 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.

[0036] The returned 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 returned 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.

[0037] The low-temperature water from the heat pump evaporator 101 enters the heat exchanger 3, and the temperature of the water is raised after heat exchange in the heat exchanger 3, and the water is returned to the heat pump evaporator 101; the high-temperature water from the refrigeration condenser 202 is returned to the refrigeration condenser 202 after heat exchange in the heat exchanger 3.

[0038] The heat pump system 1 in the embodiment is a two-stage circulation heat pump system, a first-stage circulation including the heat pump evaporator 101, the heat pump compressor one 103 and the heat pump throttling valve one 104, a second-stage circulation including the heat pump condenser 102, the heat pump compressor two 105 and the heat pump throttling valve two 106, and the first-stage circulation and the second-stage circulation sharing the composite heat exchanger 107. The structure of the composite heat exchanger is shown in the figure, and the difference is that, in the embodiment, the left side is a second-stage circulation evaporator, and the right side is a first-stage circulation condenser, and heat exchange is realized in the water tank. The two-stage circulation shares one heat exchanger, which can reduce the circulation pressure ratio and improve the energy efficiency of the air source heat pump. The first-stage circulation adopts a medium-temperature refrigerant (type: R134), and the second-stage circulation adopts a high-temperature refrigerant (type: 142b). The high-temperature refrigerant is compressed by the heat pump compressor two 105 to increase the pressure, enters the heat pump condenser 102 to release heat, and makes the 67℃ return hot water flowing out of the solvent evaporator 5 to be raised to 73℃ to re-enter the solvent evaporator 5. The hot water can also be stored in the hot water tank 4 for recycling according to needs. Figure 8 The refrigeration system 2 includes the refrigeration evaporator 201, the refrigeration condenser 202, the refrigeration compressor 203 and the refrigeration throttling valve 204. The refrigeration evaporator 201 evaporates and absorbs heat, so that the -6℃ return cold water flowing out of the solvent condenser 6 is lowered to -3℃, can be stored in the cold water tank 10, and then continues to enter the solvent condenser 6 to realize the ethyl acetate recovery circulation.

[0039] The refrigeration system 2 includes the refrigeration evaporator 201, the refrigeration condenser 202, the refrigeration compressor 203 and the refrigeration throttling valve 204. The refrigeration evaporator 201 evaporates and absorbs heat, so that the -6℃ return cold water flowing out of the solvent condenser 6 is lowered to -3℃, can be stored in the cold water tank 10, and then continues to enter the solvent condenser 6 to realize the ethyl acetate recovery circulation.

[0040] 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 are heat-exchanged in the heat exchanger 3 and then returned to the heat pump evaporator 101 and the refrigeration condenser 202 respectively.

[0041] The specific structure of the heat exchanger 3 in the embodiment is a middle water tank, including a water tank 301 and a coil 302 built in the water tank 301. The 15℃ condensed water flowing out of the heat pump evaporator 101 enters the water tank 301, is raised to 25℃ by heat exchange with the water in the coil 302, and then returns to the heat pump evaporator 101 from the bottom of the water tank. Half of the 33℃ high-temperature water flowing out of the refrigeration condenser 202 is branched by a flow divider and enters the air cooler 8 to be lowered to 28℃, and the other half enters the inlet of the coil 302 in the water tank 301 to be lowered to 31℃ by heat exchange with the water in the water tank 301, and then flows out from the outlet of the coil 302. The water temperature is 30℃ after the two routes are mixed in the mixer 9 and then returned to the refrigeration condenser 202.

[0042] The present application raises the water temperature from 15°C to 25°C by arranging the heat exchanger 3 to return the water flowing out of the heat pump evaporator 101, and exchanges the water temperature from 33°C to 30°C to return the water flowing out of the refrigeration condenser 202 to the refrigeration condenser 202, so that the heat pump evaporator 101 and the refrigeration condenser 202 can both obtain the best heat source, so that the heat pump system and the refrigeration system are always in a high energy efficiency state, without additional energy supply, energy saving and environmental protection.

[0043] The running process of Example 1 is simulated by Aspen simulation, and the simulation results are shown in Figure 3 It is shown that the heat capacity is 130 kW, the refrigeration capacity is 115 kW, the heating power is 37 kW, and the refrigeration power is 28 kW by using the intermediate water tank heat exchange. Example 2

[0044] The intermediate water tank in Example 1 is actually a heat exchanger, the hot water (33°C) from the refrigeration system is exchanged with the cold water (15°C) from the heating system, the hot water returned to the refrigeration system is cooled to 30°C, and the cold water returned to the heating system is heated to 25°C. However, the heating system hopes that the temperature at the low temperature end is as high as possible, and the refrigeration cycle hopes that the temperature at the high temperature end is as low as possible. If the intermediate water tank is not in the heat exchange mode, but the hot water of the refrigeration system is directly supplied to the heating cycle, the efficiency can be improved. Therefore, referring to Figure 4 It is shown that the intermediate water tank is cancelled, and the heat pump evaporator 101 is directly used as the heat exchanger 3, which is used as the evaporator of the heat pump system and the heat exchanger with the refrigeration system. The specific simulation process is shown in Figure 5 : The high-temperature water of 28°C flowing out of the refrigeration condenser 202 is divided into two parts by the flow divider, one part enters the heat pump evaporator 101 and is exchanged to 26°C, and the other part is cooled to 20°C by the air cooler 8 and mixed to 25°C in the mixer 9 to return to the refrigeration condenser 202.

[0045] The structure diagram of the heat exchanger 3 in this embodiment is shown in Figure 6 , which includes a water tank 301, the left side of which is used as the evaporator of the heat pump system, the inside of which circulates the refrigerant of the heat pump system, and the water tank 301 is provided with a refrigeration condenser water inlet and a refrigeration condenser water outlet, so that the high-temperature water flowing out of the refrigeration condenser 202 can be exchanged into low-temperature water.

[0046] From the simulation data of Figure 5 It can be seen that, compared with Example 1, the intermediate water tank is removed, the heat pump evaporator 101 is used as the heat exchanger 3, the heating compressor power consumption is reduced from 37 kW to 33 kW, the refrigeration compressor power consumption is reduced from 28 kW to 23 kW, and the heat exchange capacity of the air cooler is reduced from -50 kW to -41 kW. Compared with the system with the intermediate water tank, the power consumption of the system without the intermediate water tank is reduced by 15%. Embodiment 3

[0047] The heat pump system 1 in Embodiment 3 is a one-stage cycle heat pump system, as shown in Figure 7 , wherein the heat pump evaporator 101 is a three-in-one hybrid heat exchanger as the heat exchanger 3, i.e. as the evaporator 101 of the heat pump system and as the condenser 202 of the refrigeration system, wherein the heat pump system comprises 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 throttling valve 106.

[0048] The refrigeration system 2 comprises a refrigeration evaporator 201, the heat exchanger 3 (refrigeration condenser 202), a refrigeration compressor 203 and a refrigeration throttling valve 204.

[0049] The specific structure of the heat exchanger 3 is shown in Figure 8 , which comprises a water tank 301, wherein the water temperature in the water tank 301 is 30-40℃, and the evaporator of the heat pump system and the condenser of the refrigeration system realize heat exchange in the water tank 301.

[0050] As can be seen from the simulation data in Figure 9 , the refrigeration condenser of the refrigeration system has a refrigerant temperature of 62-39℃ at the inlet and outlet, while the evaporator of the heating system has a temperature of 35℃, and if the pressure is properly adjusted, the two can form a temperature difference direct heat exchange, i.e. the two-stage heat pump of the present embodiment can achieve the purpose of refrigeration and heating.

[0051] Figure 9 In the present embodiment, the refrigerant pressure of the refrigeration cycle is not changed, so the refrigeration power is unchanged, but the heating compressor energy consumption can be reduced to 21kW, and a large amount of equipment is saved, and the power consumption is reduced by 26% compared with the intermediate water tank heat exchange.

[0052] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit the present application, and other modifications or equivalent replacements to the technical solutions of the present application made by those skilled in the art should be covered in the scope of the claims of the present application as long as they do not deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A refrigeration and heat coupling system for recovering ethyl acetate, characterized by: The heat pump system (1) is a two-stage circulation heat pump system, the first stage circulation comprises the heat pump evaporator (101), a heat pump compressor one (103) and a heat pump throttling valve one (104), the second stage circulation comprises the heat pump condenser (102), a heat pump compressor two (105) and a heat pump throttling valve two (106), and the first stage circulation and the second stage circulation share a composite heat exchanger (107); The refrigeration system (2) comprises a refrigeration evaporator (201), a refrigeration condenser (202), a refrigeration compressor (203) and a refrigeration throttling valve (204); The high-temperature water flowing out of the refrigeration condenser (202) is divided by a flow divider (7), part of the high-temperature water enters the heat exchanger (3) to exchange heat, and the other part of the high-temperature water enters an air cooler (8) to be cooled, and then is mixed in a mixer (9) and returned to the refrigeration condenser (202); The heat exchanger (3) is an intermediate water tank, comprising a water tank (301), and a coil pipe (302) arranged in the water tank (301), wherein the water tank (301) is connected with the water inlet and the water outlet of the heat pump evaporator (101) on two sides respectively, and the coil pipe (302) is connected with the water inlet and the water outlet of the refrigeration condenser (202) on two ends respectively. The heat pump system (1) is a two-stage circulation heat pump system, the first stage circulation comprises the heat pump evaporator (101), a heat pump compressor one (103) and a heat pump throttling valve one (104), the second stage circulation comprises the heat pump condenser (102), a heat pump compressor two (105) and a heat pump throttling valve two (106), and the first stage circulation and the second stage circulation share a composite heat exchanger (107); The refrigeration system (2) comprises a refrigeration evaporator (201), a refrigeration condenser (202), a refrigeration compressor (203) and a refrigeration throttling valve (204); The high-temperature water flowing out of the refrigeration condenser (202) is divided by a flow divider (7), part of the high-temperature water enters the heat exchanger (3) to exchange heat, and the other part of the high-temperature water enters an air cooler (8) to be cooled, and then is mixed in a mixer (9) and returned to the refrigeration condenser (202); 2. A refrigeration and heat recovery system for recovering ethyl acetate, characterized by: The heat exchanger (3) is an intermediate water tank, comprising a water tank (301), and a coil pipe (302) arranged in the water tank (301), wherein the water tank (301) is connected with the water inlet and the water outlet of the heat pump evaporator (101) on two sides respectively, and the coil pipe (302) is connected with the water inlet and the water outlet of the refrigeration condenser (202) on two ends respectively. ​ ​ The heat pump system (1) is a two-stage circulation heat pump system, a first-stage circulation including a heat pump evaporator (101), a heat pump compressor one (103) and a heat pump throttling valve one (104), a second-stage circulation including a heat pump condenser (102), a heat pump compressor two (105) and a heat pump throttling valve two (106), the first-stage circulation and the second-stage circulation sharing a composite heat exchanger (107); The refrigeration system (2) includes a refrigeration evaporator (201), a refrigeration condenser (202), a refrigeration compressor (203) and a refrigeration throttling valve (204); The heat pump evaporator (101) is used as a heat exchanger (3), high-temperature water flowing out of the refrigeration condenser (202) is divided by a flow divider (7) into one branch entering the heat exchanger (3) for heat exchange and another branch passing through an air cooler (8) for cooling, and then mixed in a mixer (9) and returned to the refrigeration condenser (202).

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