Casting heat pump drying system and using method thereof

Abstract

The invention discloses a curtain coating heat pump drying system and a using method thereof. The curtain coating heat pump drying system comprises a preheater, a condenser, a curtain coating conveying device, a heat source tower, a water pump, an evaporator, a compressor and a throttling valve. A cold side inlet of the preheater is a fresh air inlet; a cold side outlet of the preheater is connected with a cold side inlet of the condenser; a cold side outlet of the condenser is connected with an air inlet of the casting conveying device, and an air outlet of the casting conveying device is connected with a hot side inlet of the preheater; a hot side outlet of the preheater is connected with a bottom air inlet of the heat source tower; the top of the heat source tower is an air outlet; a hot side outlet of the condenser is connected with an inlet of the throttle valve; an outlet of the throttle valve is connected with a cold-side inlet of the evaporator; a cold-side outlet of the evaporator is connected with an inlet of the compressor; an outlet of the compressor is connected with a hot side inlet of the condenser; a hot side outlet of the evaporator is connected with an upper water inlet of the heat source tower; a water pump outlet is connected with an evaporator hot side inlet. The energy utilization efficiency of the curtain coating heat pump drying system is fully improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tape casting drying and energy saving, and relates to a tape casting heat pump drying system and a use method thereof. Background Art

[0002] Casting is widely used in tobacco production, papermaking, polymer material preparation and other industrial fields due to its stable process and continuous operation. The most important and energy-consuming part of the casting process is to evaporate the excess water in the slurry to the target moisture content to achieve the drying effect. At present, the drying casting mainly relies on the high-temperature airflow and the casting to carry out convection heat exchange to remove moisture to achieve the drying effect, and is supplemented by a heat pump system composed of a compressor, evaporator, condenser and expansion valve to save energy. However, the exhaust temperature of this heat pump drying system is high, and it is difficult to recover the sensible heat and latent heat of the air. Therefore, the energy consumption of the entire system is high and the energy saving effect is poor. Summary of the invention

[0003] In order to overcome the poor energy-saving effect and low energy efficiency of the existing heat pump system, the purpose of the present invention is to provide a cast film heat pump drying system and a method of using the same, which introduces a preheater and a heat source tower to recover the sensible heat and latent heat of the exhaust gas after drying the cast film, thereby fully improving the energy utilization efficiency of the cast film heat pump drying system and enhancing the energy-saving effect.

[0004] The purpose of the present invention is achieved through the following technical solutions: A cast film heat pump drying system, characterized in that it includes a preheater, a condenser, a cast film conveying device, a heat source tower, a water pump, an evaporator, a compressor and a throttle valve; the cold side inlet of the preheater is a fresh air inlet; the cold side outlet of the preheater is connected to the cold side inlet of the condenser; the cold side outlet of the condenser is connected to the air inlet of the cast film conveying device, and the air outlet of the cast film conveying device is connected to the hot side inlet of the preheater; the hot side outlet of the preheater is connected to the air inlet at the bottom of the heat source tower; the top of the heat source tower is an exhaust outlet; the hot side outlet of the condenser is connected to the throttle valve inlet; the throttle valve outlet is connected to the cold side inlet of the evaporator, and the cold side outlet of the evaporator is connected to the compressor inlet; the compressor outlet is connected to the hot side inlet of the condenser; the hot side outlet of the evaporator is connected to the upper water inlet of the heat source tower, and the bottom water outlet of the heat source tower is connected to the water pump inlet; the water pump outlet is connected to the hot side inlet of the evaporator.

[0005] Furthermore, the preheater, condenser, casting conveyor and heat source tower constitute an air flow module; the compressor, condenser, throttle valve and evaporator constitute a refrigerant circulation module; the heat source tower, water pump and evaporator constitute a circulating water module.

[0006] The air flow module includes a preheater, a condenser, a casting conveyor and a heat source tower; the cold side inlet of the preheater is a fresh air inlet; the cold side outlet of the preheater is connected to the cold side inlet of the condenser; the cold side outlet of the condenser is connected to the air inlet of the casting conveyor, and the air outlet of the casting conveyor is connected to the hot side inlet of the preheater; the hot side outlet of the preheater is connected to the air inlet at the bottom of the heat source tower; the top of the heat source tower is an exhaust outlet; The refrigerant circulation module includes a compressor, a condenser, a throttle valve and an evaporator; wherein the hot side outlet of the condenser is connected to the throttle valve inlet; the throttle valve outlet is connected to the cold side inlet of the evaporator, the cold side outlet of the evaporator is connected to the compressor inlet; the compressor outlet is connected to the hot side inlet of the condenser; The circulating water module includes a heat source tower, a water pump and an evaporator; the hot side outlet of the evaporator is connected to the upper water inlet of the heat source tower, the bottom water outlet of the heat source tower is connected to the water pump inlet; the water pump outlet is connected to the hot side inlet of the evaporator.

[0007] A method for using a cast film heat pump drying system includes working processes of air flow, refrigerant circulation, and circulating water, as follows: S1. Air flow: The temperature of fresh air increases after being introduced into the preheater for preheating. After heat exchange with the refrigerant in the condenser, it becomes high-temperature air. After entering the casting conveyor, the high-temperature air conducts convection heat exchange with the casting and takes away moisture. The wet air discharged from the casting conveyor passes through the preheater to preheat the fresh air. Then, the preheater exhaust air with reduced temperature is introduced into the heat source tower for heat exchange with the circulating water to release latent heat and sensible heat, and finally discharged from the heat source tower to the system; S2, refrigerant cycle: the refrigerant is compressed by the compressor and becomes high-temperature and high-pressure steam. The high-temperature and high-pressure steam exchanges heat with the air through the condenser and becomes a high-temperature and high-pressure saturated solution. The saturated solution then enters the throttle valve to cool down and reduce pressure to a steam state. The refrigerant steam enters the evaporator and exchanges heat with the high-temperature circulating water, and the temperature rises. The compressor is introduced to increase temperature and pressure to restart the cycle; S3, circulating water: The high-temperature circulating water releases heat to the low-temperature refrigerant steam in the evaporator and its temperature drops. The low-temperature circulating water is sprayed in the heat source tower and heated up by heat exchange with the exhaust air introduced from the preheater. The heated circulating water is pressurized by a water pump and enters the evaporator to restart the circulation.

[0008] The casting conveying device in the casting heat pump drying system includes but is not limited to an open casting conveyor belt, a belt casting conveyor box and other equipment used for casting drying; The expanded heat collection area of ​​the filler in the heat source tower in the above-mentioned cast film heat pump drying system must be greater than 126.3 times the area of ​​the evaporator, and the resistance drop of the filler in the heat source tower is not greater than 1.5kPa. In addition, the heat source tower needs to be placed in an environment where the circulating water freezing point temperature is above 0℃; The refrigerant used in the above-mentioned cast film heat pump drying system is R11, R124, R22, R134a, R407c, R410a, R32, etc.

[0009] The beneficial effects of the present invention are as follows: Compared with the prior art, the present invention, based on the energy-saving design of the traditional heat pump system, introduces a preheater and a heat source tower to recover the sensible heat and latent heat of the exhaust gas after drying the cast film, which fully improves the energy utilization efficiency of the cast film heat pump drying system, further enhances its energy-saving effect, and meets the goals of the national energy conservation, emission reduction and sustainable development strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram of the cast film heat pump drying system.

[0011] In the figure: 1 preheater, 2 condenser, 3 casting conveyor, 4 heat source tower, 5 water pump, 6 evaporator, 7 compressor, 8 throttle valve. DETAILED DESCRIPTION

[0012] Refer to the following Figure 1 Provide detailed explanation.

[0013] A film casting heat pump drying system comprises a preheater 1, a condenser 2, a film casting conveyor 3, a heat source tower 4, a water pump 5, an evaporator 6, a compressor 7 and a throttle valve 8; the preheater comprises a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet, the condenser comprises a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet, the film casting conveyor comprises an air inlet and an air outlet, and the heat source tower comprises a bottom air inlet, a top air outlet, an upper water inlet and a bottom water outlet.

[0014] The cold side inlet of the preheater is the fresh air inlet; the cold side outlet of the preheater is connected to the cold side inlet of the condenser; the cold side outlet of the condenser is connected to the air inlet of the cast conveyor device, and the air outlet of the cast conveyor device is connected to the hot side inlet of the preheater; the hot side outlet of the preheater is connected to the air inlet at the bottom of the heat source tower; the top of the heat source tower is the exhaust outlet; the hot side outlet of the condenser is connected to the throttle valve inlet; the throttle valve outlet is connected to the cold side inlet of the evaporator, and the cold side outlet of the evaporator is connected to the compressor inlet; the compressor outlet is connected to the hot side inlet of the condenser; the hot side outlet of the evaporator is connected to the water inlet on the upper part of the heat source tower, and the water outlet at the bottom of the heat source tower is connected to the water pump inlet; the water pump outlet is connected to the hot side inlet of the evaporator.

[0015] The preheater, condenser, casting conveyor and heat source tower constitute an air flow module; the compressor, condenser, throttle valve and evaporator constitute a refrigerant circulation module; the heat source tower, water pump and evaporator constitute a circulating water module.

[0016] The invention discloses a method for using a tape-casting heat pump drying system, which is divided into three working processes according to different working media and described respectively.

[0017] S1, air flow: fresh air is introduced into the preheater 1 and preheated, and the temperature rises. After heat exchange with the refrigerant in the condenser 2, it becomes high-temperature air. After entering the casting conveyor 3, the high-temperature air performs convection heat exchange with the casting and takes away moisture. The wet air discharged from the casting conveyor 3 passes through the preheater 1 to preheat the fresh air. Then, the preheater exhaust air with reduced temperature is introduced into the heat source tower 4 to exchange heat with the circulating water to release latent heat and sensible heat, and finally discharged from the system from the top of the heat source tower 4; S2, refrigerant cycle: the refrigerant is compressed by the compressor 7 and becomes high-temperature and high-pressure steam. The high-temperature and high-pressure steam passes through the condenser 2 and exchanges heat with the air to become a high-temperature and high-pressure saturated solution. The saturated solution then enters the throttle valve 8 to cool down and reduce pressure to a steam state. The refrigerant steam enters the evaporator 6 and exchanges heat with the high-temperature circulating water, where its temperature rises. The refrigerant is introduced into the compressor 7 to increase temperature and pressure and start the cycle again. S3, circulating water: The high-temperature circulating water releases heat to the low-temperature refrigerant steam in the evaporator 6 and its temperature decreases. The low-temperature circulating water is sprayed in the heat source tower 4 and is heated by heat exchange with the exhaust air introduced from the preheater 1. The heated circulating water is pressurized by the water pump 5 and enters the evaporator 6 to restart the circulation.

[0018] The expanded heat collection area of ​​the filler in the heat source tower in the above-mentioned cast film heat pump drying system must be greater than 126.3 times the area of ​​the evaporator, and the resistance drop of the filler in the heat source tower is not greater than 1.5kPa. In addition, the heat source tower needs to be placed in an environment where the circulating water freezing point temperature is above 0℃; The refrigerant in the above-mentioned cast film heat pump drying system can be R11, R124, R22, R134a, R407c, R410a, R32, etc.

[0019] The present invention introduces a preheater and a heat source tower to recover the sensible heat and latent heat of the exhaust gas after drying and casting, which fully improves the energy utilization efficiency of the casting heat pump drying system and further enhances its energy-saving effect.

Claims

1. A cast film heat pump drying system, characterized in that: The invention comprises a preheater (1), a condenser (2), a film casting conveyor (3), a heat source tower (4), a water pump (5), an evaporator (6), a compressor (7) and a throttle valve (8); the cold side inlet of the preheater (1) is a fresh air inlet, and the cold side outlet of the preheater is connected to the cold side inlet of the condenser (2); the cold side outlet of the condenser (2) is connected to the air inlet of the film casting conveyor (3), and the air outlet of the film casting conveyor (3) is connected to the hot side inlet of the preheater (1); the hot side outlet of the preheater (1) is connected to the bottom inlet of the heat source tower (4). The heat source tower (4) is connected to the air outlet; an exhaust outlet is provided at the top of the heat source tower; the hot side outlet of the condenser (2) is connected to the inlet of the throttle valve (8); the outlet of the throttle valve (8) is connected to the cold side inlet of the evaporator (6), and the cold side outlet of the evaporator (6) is connected to the inlet of the compressor (7); the outlet of the compressor (7) is connected to the hot side inlet of the condenser (2); the hot side outlet of the evaporator (6) is connected to the upper water inlet of the heat source tower (4), and the bottom water outlet of the heat source tower (4) is connected to the inlet of the water pump (5); the outlet of the water pump (5) is connected to the hot side inlet of the evaporator (6).

2. The cast film heat pump drying system according to claim 1, characterized in that: The preheater (1), the condenser (2), the casting conveyor (3) and the heat source tower (4) constitute an air flow module; the compressor (7), the condenser (2), the throttle valve (8) and the evaporator (6) constitute a refrigerant circulation module; and the heat source tower (4), the water pump (5) and the evaporator (6) constitute a circulating water module.

3. The cast film heat pump drying system according to claim 1, characterized in that: The casting conveyor device (3) is an open casting conveyor belt or a belt-type casting conveyor box.

4. The casting heat pump drying system according to claim 1, characterized in that: The expanded heat collection area of ​​the filler in the heat source tower (4) is greater than 126.3 times the area of ​​the evaporator (6), the resistance drop of the filler in the heat source tower (4) is not greater than 1.5 kPa, and the heat source tower (4) is placed in an environment with a circulating water freezing point temperature above 0°C.

5. A method for using a cast film heat pump drying system, characterized in that: The working process includes air flow, refrigerant circulation, and circulating water, as follows: S1. Air flow: The temperature of fresh air increases after being introduced into the preheater for preheating. After heat exchange with the refrigerant in the condenser, it becomes high-temperature air. After entering the casting conveyor, the high-temperature air conducts convection heat exchange with the casting and takes away moisture. The wet air discharged from the casting conveyor passes through the preheater to preheat the fresh air. Then, the preheater exhaust air with reduced temperature is introduced into the heat source tower for heat exchange with the circulating water to release latent heat and sensible heat, and finally discharged from the heat source tower to the system; S2, refrigerant cycle: the refrigerant is compressed by the compressor and becomes high-temperature and high-pressure steam. The high-temperature and high-pressure steam exchanges heat with the air through the condenser and becomes a high-temperature and high-pressure saturated solution. The saturated solution then enters the throttle valve to cool down and reduce pressure to a steam state. The refrigerant steam enters the evaporator and exchanges heat with the high-temperature circulating water, and the temperature rises. The compressor is introduced to increase temperature and pressure to restart the cycle; S3, circulating water: The high-temperature circulating water releases heat to the low-temperature refrigerant steam in the evaporator and its temperature drops. The low-temperature circulating water is sprayed in the heat source tower and heated up by heat exchange with the exhaust air introduced from the preheater. The heated circulating water is pressurized by a water pump and enters the evaporator to restart the circulation.

6. The casting heat pump drying system according to claim 5, characterized in that: The refrigerant uses any one of R11, R124, R22, R134a, R407c, R410a, and R32.

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