Flash condensate waste heat recycling system

Abstract

The utility model provides a flash condensate waste heat recycling system, and belongs to the technical field of waste heat recycling. The system comprises a steam flash tank, a node heat exchanger and a condensate collecting tank which are communicated in sequence, wherein the node heat exchanger is also communicated with a nitrogen drying tower. According to the system, by means of gas-liquid heat exchange with nitrogen, the temperature of flash evaporation condensate at 125-135 DEG C obtained through flash evaporation of a steam flash evaporation tank is reduced to 70-80 DEG C, and cavitation of an external hot water delivery pump and the risk of liquid impact when the condensate is mixed with condensate at the temperature lower than 100 DEG C are avoided; and meanwhile, desalted water is prevented from being used for cooling the flash evaporation condensate, so that the cost is saved. The waste heat of the flash evaporation condensate obtained through flash evaporation of the steam flash evaporation tank is utilized, the temperature of 20-30 DEG C of nitrogen is increased to 70-80 DEG C, the use amount of a steam heater is reduced, energy consumption is reduced, and the use amount of the steam heater is reduced by about 1 ton / hour. The cost recovery period of the system is about half a year, and economic benefits are good.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of waste heat recycling, and relates to a flash condensation liquid waste heat recycling system. BACKGROUND

[0002] The devolatilization drying system is a system for removing polymer solvent in the polycarbonate synthesis process, and has the advantages of low energy consumption, small pollution and low cost.

[0003] In the devolatilization drying system, high-temperature steam with a pressure of 1.0 Mpa enters the flash system to flash out steam with a pressure of 0.2 MPa, and the remaining flash condensation liquid still has a temperature of about 130 DEG C. If the part of the flash condensation liquid is directly sent out through the heat pump, the heat pump is prone to cavitation due to the excessively high temperature, thereby affecting the performance of the pump body. In addition, if the part of the flash condensation liquid is mixed with other low-temperature condensation liquid, liquid hammer is caused due to the large temperature difference, thereby causing safety problems.

[0004] To prevent the above safety problems, desalted water is usually added to the part of the flash condensation liquid to reduce the temperature to 100 DEG C, and then the part of the flash condensation liquid is transported to the condensation liquid pipe network for use as make-up water of other devices. However, such a treatment method causes the heat carried by the part of the flash condensation liquid to be wasted, thereby causing energy waste; and the use of the desalted water also increases the treatment cost. CONTENT OF THE UTILITY MODEL

[0005] The utility model aims at providing a flash condensation liquid waste heat recycling system to solve the problem of heat waste of the flash condensation liquid after the flash treatment.

[0006] To achieve the above object, the utility model adopts the following technical scheme:

[0007] In a first aspect, the application provides a flash condensation liquid waste heat recycling system, which comprises a steam flash tank, a wave node heat exchanger and a condensation liquid collecting tank connected in sequence.

[0008] Preferably, the wave node heat exchanger is connected with an inlet liquid pipeline and an outlet liquid pipeline, and the inlet liquid pipeline is connected with the steam flash tank, and the outlet liquid pipeline is connected with the condensation liquid collecting tank.

[0009] Preferably, a condensation liquid flow meter and an inlet liquid adjusting valve are arranged on the inlet liquid pipeline, and the inlet liquid adjusting valve is located between the condensation liquid flow meter and the wave node heat exchanger.

[0010] Preferably, an outlet liquid adjusting valve is arranged on the outlet liquid pipeline.

[0011] Preferably, a flow adjusting valve group is further arranged between the steam flash tank and the inlet liquid pipeline.

[0012] Preferably, the steam flash tank is also connected to a steam regulating valve group.

[0013] The utility model has the following beneficial effects:

[0014] (1) By the way of gas-liquid heat exchange with nitrogen, the flash condensate liquid of 125-135℃ flashed out by the steam flash tank is reduced to 70-80℃, avoiding the risk of cavitation of the hot water pump and liquid impact when mixed with the condensate liquid below 100℃; at the same time, the use of desalted water to cool the flash condensate liquid is avoided, saving cost.

[0015] (2) The waste heat of the flash condensate liquid flashed out by the steam flash tank is used to heat the nitrogen of 20-30℃ to 70-80℃, reducing the use amount of the steam heater, saving energy consumption, and the use amount of the steam heater is reduced by about 1 ton / hour.

[0016] (3) The cost recovery period of the system is about half a year, and the economic benefit is good. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure diagram of the flash condensate liquid waste heat recycling system provided by the embodiment of the application is shown in the figure;

[0018] Symbols represent:

[0019] 1-steam flash tank, 2-corrugated heat exchanger, 3-condensate collection tank, 4-nitrogen drying tower, 5-liquid inlet pipeline, 6-liquid outlet pipeline, 7-condensate flow meter, 8-liquid inlet regulating valve, 9-liquid outlet regulating valve, 10-flow adjusting valve group, 11-steam regulating valve group. DETAILED DESCRIPTION

[0020] The technical scheme of the utility model will be further explained and described through specific embodiments.

[0021] The embodiment of the application provides a flash condensate liquid waste heat recycling system, which comprises a steam flash tank 1, a corrugated heat exchanger 2 and a condensate collection tank 3 connected in sequence, and the corrugated heat exchanger 2 is also connected to a nitrogen drying tower 4, as shown in the figure. Figure 1

[0022] The steam flash tank 1 is a component for high-temperature steam flashing in a devolatilization drying system, which is connected to the corrugated heat exchanger 2 and a steam regulating valve group 11. High-temperature steam is used for flashing in the steam flash tank 1 by using its high-temperature heat, and the flash condensate liquid of 125-135℃ and steam are flashed out, wherein the steam is discharged under the regulation of the steam regulating valve group 11. The flash condensate liquid still has a large amount of heat, and in the embodiment of the application, the part of the flash condensate liquid is transported to the corrugated heat exchanger 2 to realize gas-liquid heat exchange. ​

[0023] The bellow heat exchanger 2 is a component for realizing gas-liquid heat exchange between the flash condensate and nitrogen. Specifically, the bellow heat exchanger 2 is connected with the liquid inlet pipeline 5 and the liquid outlet pipeline 6 respectively, and the liquid inlet pipeline 5 is connected with the steam flash tank 1, and the liquid outlet pipeline 6 is connected with the condensate collecting tank 3. Thus, the flash condensate flashed out from the steam flash tank 1 enters the bellow heat exchanger 2 through the liquid inlet pipeline 5. Meanwhile, the nitrogen dried by the nitrogen drying tower 4 of the adjacent floor and position is introduced into the bellow heat exchanger 2. In the bellow heat exchanger 2, the flash condensate at 125-135℃ exchanges heat with the nitrogen at 20-30℃, and the condensate at 70-80℃ and the nitrogen at 70-80℃ are obtained, realizing the secondary utilization of the flash condensate, recovering the energy, and improving the temperature of the nitrogen. In the embodiment of the present application, the flow rate of the flash condensate is 15m 3 / h, and the flow rate of the nitrogen is 50000m 3 / h.

[0024] The condensate after cooling enters the condensate collecting tank 3 through the liquid outlet pipeline 6 by using the height difference of the floor. Since the temperature of the condensate after heat exchange is reduced to 70-80℃, the cavitation of the hot water pump is avoided; meanwhile, when mixed with the condensate in the condensate collecting tank 3 at a temperature lower than 100℃, the pipeline vibration is not caused, and thus the risk of liquid impact is not caused, improving the safety. In addition, through the heat exchange with the nitrogen, the use of desalted water to cool the flash condensate is avoided, saving the cost.

[0025] The nitrogen heated to 70-80℃ is delivered to the steam heater by the nitrogen delivery fan, so as to be heated to about 135℃ by the steam heater and then directly used. Since the steam heater is used to heat the nitrogen from 70-80℃ to about 135℃, instead of heating the nitrogen from 20-30℃ to about 135℃, the use amount of the steam heater is greatly reduced, the energy consumption is saved, and the use amount of the steam heater is reduced by about 1 ton / h.

[0026] In order to control the flow rate and feeding time of the flash condensate entering the bellow heat exchanger 2, the condensate flow meter 7 and the liquid inlet adjusting valve 8 are arranged on the liquid inlet pipeline 5, and the liquid inlet adjusting valve 8 is located between the condensate flow meter 7 and the bellow heat exchanger 2. Similarly, in order to control the start and stop of the condensate after heat exchange in the bellow heat exchanger 2 flowing to the condensate collecting tank 3, the liquid outlet adjusting valve 9 is arranged on the liquid outlet pipeline 6. Further, in order to control the flow rate of the flash condensate flashed out from the steam flash tank 1 entering the liquid inlet pipeline 5, the flow rate adjusting valve group 10 is further arranged between the steam flash tank 1 and the liquid inlet pipeline 5.

[0027] The nitrogen drying tower 4 is a component for drying nitrogen, and the dried nitrogen is introduced into the bellow heat exchanger 2 to exchange heat with the flash condensate, improving the temperature of the nitrogen.

[0028] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A flash condensate liquid waste heat reuse system, characterized by, The device comprises a vapor flash tank (1), a wave node heat exchanger (2) and a condensate collecting tank (3) connected in sequence.

2. The flash condensation liquid waste heat recycling system according to claim 1, characterized in that, The wave node heat exchanger (2) is connected with an inlet liquid pipeline (5) and an outlet liquid pipeline (6) respectively, the inlet liquid pipeline (5) is connected with the vapor flash tank (1), and the outlet liquid pipeline (6) is connected with the condensate collecting tank (3).

3. The flash condenser liquid waste heat reuse system of claim 2, wherein, A condensate flow meter (7) and an inlet liquid regulating valve (8) are arranged on the inlet liquid pipeline (5), and the inlet liquid regulating valve (8) is located between the condensate flow meter (7) and the wave node heat exchanger (2).

4. The flash condenser liquid waste heat reuse system of claim 2, wherein, An outlet liquid regulating valve (9) is arranged on the outlet liquid pipeline (6).

5. The flash condenser liquid waste heat reuse system of claim 2, wherein, A flow adjusting valve group (10) is further arranged between the vapor flash tank (1) and the inlet liquid pipeline (5).

6. The flash condensation liquid waste heat reuse system of claim 1, wherein, The vapor flash tank (1) is further connected with a steam regulating valve group (11).

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