Low-temperature flue gas utilization system for painting workshop

Abstract

The application discloses a kind of painting workshop low-temperature flue gas utilization systems, including chimney, be in the passage control valve of chimney passage, control device, flue gas introduction device, shunt device, flow detection device, multiple units, with the multiple first control valves of control device signal connection and multiple water heat exchange devices, the inlet of flue gas introduction device is connected with the inlet end of chimney passage, water heat exchange device includes water supply pipeline, unit includes evaporator, gas-liquid separator, compressor, condenser, expansion valve and refrigerant, evaporator includes flue gas inlet and flue gas outlet, condenser includes inlet and outlet, shunt device includes the shunt inlet connected with the outlet of flue gas introduction device and multiple shunt outlets, a first control valve is arranged between each shunt outlet and flue gas inlet, flow detection device is connected between flue gas introduction device and shunt inlet, control device controls several openings in multiple first control valves according to the detection result of flow detection device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating exhaust gas utilization, in particular to a coating workshop low-temperature flue gas utilization system. BACKGROUND

[0002] Coating refers to covering a protective layer or a decorative layer on the surface of metal and non-metal, and is a basic technical means for product surface protection and decoration. Coating process can be simply summarized as: pretreatment → spraying → drying or curing. Pretreatment generally includes oil removal, rust removal and passivation (phosphating) process. According to different coating layers and corrosion resistance requirements, the treatment methods such as oil removal, rust removal and phosphating are selected according to the condition of the workpiece raw material. In the rust removal process of pretreatment, sand blasting, shot blasting or polishing process is also used as needed in different departments of different industries. The coating workshop exhaust gas mainly contains organic solvents in the coating and decomposition products during spraying and drying, which are collectively referred to as volatile organic compounds (VOCs), and the main components are benzene, toluene and xylene. These components are harmful to human health and living environment, and have a foul odor. If a person inhales low-concentration organic waste gas for a long time, it will cause chronic respiratory diseases such as cough, chest tightness, asthma and emphysema. The harmful exhaust gas discharged in coating is mainly concentrated in the paint spraying production line, and the paint spraying room, drying room and drying room are the main sources of exhaust gas. The gas discharged from the electrophoresis, intermediate coating and top coating drying room belongs to high-temperature and high-concentration exhaust gas, which is suitable for incineration treatment. At present, the commonly used coating exhaust gas treatment technology measures in the drying process are: regenerative thermal oxidation technology (RTO), regenerative catalytic combustion technology (RCO) and recovery type thermal incineration system (TNV). After the volatile organic compounds are treated by combustion and heat recovery, the low-temperature flue gas temperature is usually below 40℃, the flow is unstable, the heat is low, the quality is low, and the recovery and utilization are difficult. Many industrial and mining enterprises directly discharge it. The amount of low-temperature waste heat resources is huge, and the distribution is extensive. If not recycled and utilized, it will cause great waste. SUMMARY

[0003] The purpose of the present application is to provide a coating workshop low-temperature flue gas utilization system capable of effectively utilizing the low-temperature flue gas generated by the coating workshop after the volatile organic compounds are treated by combustion and heat recovery.

[0004] The application discloses a kind of painting workshop low-temperature flue gas utilization system, including chimney, be located in the passage control valve of the chimney passage, control device, flue gas introduction device, shunt device, with the flow detection device of the control device signal connection, multiple units, with the signal connection of the control device multiple first control valve and multiple water heat exchange device, the chimney is used to from its inlet end passage volatile organic compounds generated in painting workshop after combustion and heat recovery treatment low-temperature flue gas and flue gas is discharged from its outlet end, the passage control valve is used to control the communication or disconnection of the inlet end and outlet end of the chimney passage, the inlet of the flue gas introduction device is connected with the inlet end of the chimney passage to be used to introduce the low-temperature flue gas of the inlet end of the chimney, the water heat exchange device includes water supply pipeline for outputting water to be heated, the unit includes evaporator, gas-liquid separator connected with the evaporator, compressor with the gas outlet of the gas-liquid separator is connected, condenser connected with the compressor, expansion valve connected with the condenser, and refrigerant circulating flow in the evaporator, the gas-liquid separator, the compressor, the condenser and the expansion valve, the evaporator includes the evaporator side refrigerant inlet connected with the outlet of the expansion valve, the evaporator side refrigerant outlet for outputting heat-absorbed evaporated refrigerant and being connected with the inlet of the gas-liquid separator, flue gas inlet for passing into low-temperature flue gas to heat the refrigerant located in evaporator, and flue gas outlet for outputting low-temperature flue gas after heat dissipation, the condenser includes the condensation side refrigerant inlet connected with the outlet of the compressor, the condensation side refrigerant outlet for outputting heat-dissipated refrigerant and being connected with the inlet of the expansion valve, water inlet for passing into water to be heated exported by the water supply pipeline to heat the refrigerant located in condenser, and water outlet for outputting hot water after absorbing the heat of the refrigerant, the shunt device includes shunt inlet connected with the outlet of the flue gas introduction device, and multiple shunt outlets are respectively connected with the flue gas inlet of the evaporator of the multiple units one by one, each shunt outlet and flue gas inlet are equipped with one by opening or closing to control the communication or disconnection between shunt outlet and flue gas inlet the first control valve, the flow detection device is connected between the flue gas introduction device and the shunt inlet, the control device controls several of the multiple first control valves to open according to the detection result of the flow detection device.

[0005] In some embodiments, the water storage tank is further included, the water feeding pipe is connected between the water inlet of the condenser and the water storage tank, the water heat exchange device further comprises a water returning pipe connected between the water outlet of the condenser and the water storage tank for outputting hot water after absorbing heat of the refrigerant to the water storage tank, the water heat exchange device further comprises a water pump arranged on the water feeding pipe and a temperature detecting device arranged on the water returning pipe for detecting temperature of the hot water input to the water storage tank, the control device is signal connected with the temperature detecting device and the compressor, and the control device controls the rotating speed and / or compression ratio of the compressor according to the detection result of the temperature detecting device.

[0006] In some embodiments, the hot water input to the water storage tank is used for cleaning the workpiece to be coated.

[0007] In some embodiments, a low pressure controller arranged between the gas-liquid separator and the compressor and a high pressure controller arranged between the compressor and the condenser are further included, the low pressure controller and the high pressure controller respectively comprise a first pressure detector and a second pressure detector for detecting inlet pressure and outlet pressure of the compressor, the control device is signal connected with the first pressure detector and the second pressure detector, and the control device controls whether to cut off power of the compressor according to the detection result of the first pressure detector and the second pressure detector.

[0008] In some embodiments, the plurality of units is four units, the shunting device comprises a main pipe with a rectangular cross section and four branch pipes with a rectangular cross section in communication with the main pipe, the inlet of the main pipe is the shunting inlet, the outlets of the four branch pipes are the shunting outlets, the four branch pipes have the same cross sectional shape and are uniformly and centrally symmetrically distributed.

[0009] In some embodiments, the main pipe is a straight cylinder pipe, and the branch pipe comprises a first straight cylinder part connected with the main pipe and a second straight cylinder part with an axis at an obtuse angle with the axis of the first straight cylinder part.

[0010] In some embodiments, the flue gas outlet of the evaporator is connected with the outlet end of the chimney.

[0011] In some embodiments, the flue gas introduction device is an induced draft fan, and the low-temperature flue gas utilization system in the painting workshop further includes a confluence device for controlling the connection or disconnection of the pipeline. The confluence device includes a plurality of confluence inlets connected to the flue gas outlets of each of the evaporators and a confluence outlet connected to the outlet end of the chimney. The second control valve is located on the pipeline between the induced draft fan and the inlet end of the chimney, and the third control valve is located on the pipeline between the confluence outlet and the outlet end of the chimney.

[0012] Based on the low-temperature flue gas utilization system for painting workshops provided by this invention, by employing channel control valves, control devices, flue gas introduction devices, diversion devices, flow detection devices connected to the control devices, multiple units, multiple first control valves connected to the control devices, and multiple water heat exchange devices, a matching number of units can be selected according to the flow rate of the low-temperature flue gas generated in the painting workshop after combustion and heat recovery treatment of volatile organic compounds. The heat recovery of the low-temperature flue gas and the water supplied by the water heat exchange devices can be used for cleaning of painted workpieces, etc., to achieve effective utilization of low-temperature flue gas with large flow fluctuations and low temperature.

[0013] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0015] Figure 1 This is a schematic diagram of the principle of a low-temperature flue gas utilization system in a painting workshop according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure of a diversion device according to another embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0019] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0022] like Figure 1As shown, the low-temperature flue gas utilization system for the painting workshop in this embodiment includes a chimney 1, a channel control valve 11 located within the channel of the chimney 1, a control device, a flue gas inlet device 2, a diversion device 3, a flow detection device 71 connected to the control device, multiple units, multiple first control valves 61 connected to the control device, and multiple water heat exchangers. The low-temperature flue gas generated in the painting workshop, after combustion and heat recovery treatment, is typically below 40°C. This low-temperature flue gas enters from the inlet end of the chimney 1, and the outlet end of the chimney 1 is used to discharge the flue gas. The channel control valve 11 is used to control the connection or disconnection of the inlet and outlet ends of the channel of the chimney 1. The inlet of the flue gas inlet device 2 is connected to the inlet end of the channel of the chimney 1 to introduce the low-temperature flue gas from the inlet end of the chimney 1. The water heat exchangers include a water supply pipe for outputting water to be heated. The unit includes an evaporator 45, a gas-liquid separator 46 connected to the evaporator 45, a compressor 41 whose inlet is connected to the gas outlet of the gas-liquid separator 46, a condenser 43 connected to the compressor 41, an expansion valve 44 connected to the condenser 43, and refrigerant circulating within the evaporator 45, the gas-liquid separator 46, the compressor 41, the condenser 43, and the expansion valve 44. The evaporator 45 includes an evaporator-side refrigerant inlet connected to the outlet of the expansion valve 44, an evaporator-side refrigerant outlet for discharging the refrigerant after heat absorption and evaporation and connected to the inlet of the gas-liquid separator 46, a flue gas inlet for introducing low-temperature flue gas to dissipate heat to the refrigerant located within the evaporator 45, and a flue gas outlet for dissipating the dissipated low-temperature flue gas. The condenser 43 includes a condenser-side refrigerant inlet connected to the outlet of the compressor 41, a condenser-side refrigerant outlet for dissipating the dissipated refrigerant and connected to the inlet of the expansion valve 44, and a water supply pipe for introducing hot water to dissipate heat from the refrigerant located in the condenser 43. The system includes a heat-absorbing inlet and an outlet for hot water after absorbing the heat from the refrigerant. The diversion device 3 includes a diversion inlet connected to the outlet of the flue gas inlet device 2 and multiple diversion outlets connected to the flue gas inlets of the evaporators 45 of multiple units. Each diversion outlet and flue gas inlet is connected to a first control valve 61, which controls the connection or disconnection between the diversion outlet and the flue gas inlet by opening or closing. A flow detection device 71 is connected between the flue gas inlet device 2 and the diversion inlet. The control device controls several of the first control valves 61 to open based on the detection result of the flow detection device 71. Each unit has its appropriate power during normal operation. When using the unit to exchange heat with low-temperature flue gas, if the flow rate of the low-temperature flue gas is too high, the unit cannot effectively exchange heat with the low-temperature flue gas, resulting in low heat utilization efficiency. If the flow rate of the low-temperature flue gas is too low, the unit consumes a large amount of heat exchange energy, wasting energy and resulting in energy waste.Based on the detection results of the flow detection device, the control device opens an appropriate number of first control valves 61, thereby opening an appropriate number of units to exchange heat with the low-temperature flue gas. This allows for the effective utilization of the heat from the low-temperature flue gas while minimizing the waste of unit operating energy.

[0023] During operation, the low-temperature flue gas from the volatile organic compounds (VOCs) generated in the painting workshop, after combustion and heat recovery treatment, is introduced into chimney 1 from the inlet end. At this time, the channel control valve 11 is in the closed state, and the inlet and outlet ends of chimney 1 are not connected within the channel of chimney 1. The flue gas introduction device 2 introduces the low-temperature flue gas from the inlet end of chimney 1. After the flow detection device detects the flow rate of the low-temperature flue gas, it is discharged into the diversion device. The control device determines how many first control valves 61 to open based on the detection results of the flow detection device, thereby correspondingly starting several units for heat exchange. Low-temperature flue gas flows out from the several branch outlets corresponding to the opened first control valves. After passing through the first control valves, it enters the evaporator through the flue gas inlet of the corresponding unit's evaporator. Low-temperature, low-pressure liquid refrigerant is introduced into the evaporator's evaporator-side refrigerant inlet. The low-temperature, low-pressure liquid refrigerant exchanges heat with the low-temperature flue gas in the evaporator. After absorbing the heat from the low-temperature flue gas, the refrigerant becomes a low-temperature, low-pressure gas and is output from the evaporator-side refrigerant outlet. After passing through the gas-liquid separator, the gaseous refrigerant flows out from the gas outlet of the gas-liquid separator and enters the compressor. The compressor compresses the gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant and outputs it. The high-temperature, high-pressure gaseous refrigerant enters the condenser through the condenser-side refrigerant inlet and exchanges heat with the water to be heated entering the condenser through the water inlet. After dissipating heat, the high-temperature, high-pressure gaseous refrigerant becomes a medium-temperature, high-pressure liquid refrigerant and is output from the condenser-side refrigerant outlet. The heated hot water is output from the water outlet and utilized. The medium-temperature, high-pressure liquid refrigerant then enters the expansion valve, expands, and becomes a low-temperature, low-pressure liquid refrigerant, which is then output and enters the evaporator.

[0024] The low-temperature flue gas utilization system for the painting workshop in this embodiment employs a channel control valve 11, a control device, a flue gas inlet device 2, a diversion device 3, a flow detection device 71 connected to the control device, multiple units, multiple first control valves 61 connected to the control device, and multiple water heat exchangers. It can select a matching number of units based on the flow rate of the low-temperature flue gas generated in the painting workshop after combustion and heat recovery of volatile organic compounds. This allows for the recovery of heat from the low-temperature flue gas and the heating of water supplied by the water heat exchangers. The heated water can then be used for cleaning painted workpieces, achieving effective utilization of the low-temperature flue gas with large flow fluctuations and low temperature.

[0025] In some embodiments, such as Figure 1As shown, the low-temperature flue gas utilization system in the painting workshop also includes a water storage tank 50. A water supply pipe is connected between the inlet of the condenser 43 and the water storage tank 50. The water heat exchange device also includes a return water pipe connected between the outlet of the condenser 43 and the water storage tank 50 for outputting hot water after absorbing heat from the refrigerant to the water storage tank 50. The water heat exchange device also includes a water pump 51 installed on the water supply pipe and a temperature detection device 52 installed on the return water pipe. The temperature detection device 52 is used to detect the temperature of the hot water input to the water storage tank 50. The control device is signal-connected to the temperature detection device 52 and the compressor 41. The control device controls the speed and / or compression ratio of the compressor 41 according to the detection result of the temperature detection device 52. When the temperature detection device detects that the hot water temperature is low, the control device increases the speed and / or compression ratio of the compressor corresponding to the water heat exchange device to increase the hot water temperature. When the temperature detection device detects that the hot water temperature is high, the control device decreases the speed and / or compression ratio of the compressor corresponding to the water heat exchange device to decrease the hot water temperature. In some embodiments, hot water supplied to the water tank 50 is used to clean the workpiece to be coated.

[0026] In some embodiments, the low-temperature flue gas utilization system in the painting workshop further includes a low-pressure controller 47 located between the gas-liquid separator 46 and the compressor 41, and a high-pressure controller 42 located between the compressor 41 and the condenser 43. The low-pressure controller 47 and the high-pressure controller 42 each include a first pressure detector and a second pressure detector for detecting the inlet and outlet pressures of the compressor 41. The control device is connected to the first and second pressure detectors, and controls whether to cut off the power to the compressor 41 based on the detection results of the first and second pressure detectors. During compressor operation, due to refrigerant piping issues or the compressor itself, the outlet pressure may be too high or the suction pressure too low. Therefore, a low-pressure controller is arranged at the front end of the compressor, and a high-pressure controller is arranged at the rear end of the compressor, and they are linked together. When the outlet pressure exceeds a given value, the control device directly cuts off the compressor power to stop it; when the suction pressure is below a given value, the control device also cuts off the compressor power to stop it.

[0027] In some embodiments, such as Figure 1 and Figure 2As shown, the multiple units are divided into four units. The diversion device 3 includes a main pipe 31 with a rectangular cross-section and four branch pipes 32 with rectangular cross-sections connected to the main pipe 31. The inlet of the main pipe 31 is the diversion inlet, and the outlet of the four branch pipes 32 is the diversion outlet. The four branch pipes 32 have the same cross-sectional shape and are evenly and centrally symmetrically distributed. Based on the results of multiphysics simulation analysis, this embodiment adopts a spatially distributed rectangular pipe structure to divert low-temperature flue gas, which can effectively reduce the flow velocity of high-flow flue gas and ensure that the flow rate and velocity of flue gas in each branch pipe are basically equal.

[0028] In some embodiments, the main pipe 31 is a straight cylindrical pipe, and the branch pipe 32 includes a first straight cylindrical section connected to the main pipe 31 and a second straight cylindrical section whose axis forms an obtuse angle with the axis of the first straight cylindrical section. This arrangement helps to reduce the flow resistance of the low-temperature flue gas, making the utilization of the low-temperature flue gas more efficient.

[0029] In some embodiments, the maximum operating flow rate of the low-temperature flue gas utilization system in the painting workshop is Q. When the flow detection device detects a low-temperature flue gas flow rate of (0, Q / 4), one first control valve is opened, corresponding to the start of one unit. When the flow detection device detects a low-temperature flue gas flow rate of (Q / 2, 3Q / 4), two first control valves are opened, corresponding to the start of two units. When the flow detection device detects a low-temperature flue gas flow rate of (Q / 2, 3Q / 4), three first control valves are opened, corresponding to the start of three units. When the flow detection device detects a low-temperature flue gas flow rate of (3Q / 4, Q), four first control valves are opened, corresponding to the start of four units.

[0030] In some embodiments, such as Figure 1 As shown, the flue gas outlet of the evaporator 45 is connected to the outlet end of the chimney 1. The low-temperature flue gas, after being heated by the evaporator, continues to return to the outlet end of the chimney 1 for unified discharge and treatment, resulting in a more efficient emission arrangement.

[0031] In some embodiments, such as Figure 1As shown, the flue gas inlet device 2 is an induced draft fan. The low-temperature flue gas utilization system in the painting workshop also includes a confluence device and a second control valve 62 and a third control valve 63 for controlling the connection or disconnection of the pipelines. The confluence device includes multiple confluence inlets connected to the flue gas outlets of each evaporator 45 and a confluence outlet connected to the outlet end of the chimney 1. The second control valve 62 is located on the pipeline between the induced draft fan and the inlet end of the chimney 1, and the third control valve 63 is located on the pipeline between the confluence outlet and the outlet end of the chimney 1. The second control valve 62 controls whether the low-temperature flue gas enters the flue gas inlet device, and the third control valve 63 controls whether the low-temperature flue gas after heat exchange is discharged to the outlet end of the chimney 1. When the low-temperature flue gas utilization system in the painting workshop is not working, the second control valve 62 and the third control valve 63 are closed, and the channel control valve of the chimney 1 is opened, so that the chimney 1 can carry out normal low-temperature flue gas discharge.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A low-temperature flue gas utilization system for a painting workshop, characterized in that, The system includes a chimney, a channel control valve located within the chimney's channel, a control device, a flue gas inlet device, a diversion device, a flow detection device signal-connected to the control device, multiple generator units, multiple first control valves signal-connected to the control device, and multiple water heat exchangers. The chimney is used to introduce low-temperature flue gas from the painting workshop (after combustion and heat recovery of volatile organic compounds) at its inlet end and to discharge the flue gas at its outlet end. The channel control valve controls the connection or disconnection of the inlet and outlet ends of the chimney's channel. The inlet of the flue gas inlet device is connected to... The inlet end of the chimney passage is connected to introduce low-temperature flue gas into the chimney. The water heat exchanger includes a water supply pipe for outputting water to be heated. The unit includes an evaporator, a gas-liquid separator connected to the evaporator, a compressor whose inlet is connected to the gas outlet of the gas-liquid separator, a condenser connected to the compressor, an expansion valve connected to the condenser, and a refrigerant circulating within the evaporator, the gas-liquid separator, the compressor, the condenser, and the expansion valve. The evaporator includes an evaporator-side refrigeration unit connected to the outlet of the expansion valve. The system comprises: a refrigerant inlet, an evaporator-side refrigerant outlet connected to the inlet of the gas-liquid separator for discharging refrigerant after heat absorption and evaporation, a flue gas inlet for introducing low-temperature flue gas to dissipate heat to the refrigerant located in the evaporator, and a flue gas outlet for dissipating the dissipated low-temperature flue gas. The condenser includes a condenser-side refrigerant inlet connected to the outlet of the compressor, a condenser-side refrigerant outlet connected to the inlet of the expansion valve for dissipating the dissipated refrigerant, a water inlet for introducing water to be heated from the water supply pipe to absorb heat from the refrigerant located in the condenser, and a water outlet for dissipating hot water after absorbing heat from the refrigerant. The flow distribution device includes a flow distribution inlet connected to the outlet of the flue gas inlet device and multiple flow distribution outlets respectively connected to the flue gas inlets of the evaporators of the multiple units. Each flow distribution outlet and the flue gas inlet are provided with a first control valve that controls the connection or disconnection between the flow distribution outlet and the flue gas inlet by opening or closing. The flow detection device is connected between the flue gas inlet device and the flow distribution inlet. The control device controls several of the multiple first control valves to open according to the detection result of the flow detection device.

2. The low-temperature flue gas utilization system for painting workshops as described in claim 1, characterized in that, The device also includes a water storage tank. The water supply pipe is connected between the inlet of the condenser and the water storage tank. The water heat exchange device also includes a return water pipe connected between the outlet of the condenser and the water storage tank for outputting hot water that has absorbed the heat of the refrigerant to the water storage tank. The water heat exchange device also includes a water pump installed on the water supply pipe and a temperature detection device installed on the return water pipe. The temperature detection device is used to detect the temperature of the hot water input to the water storage tank. The control device is signal-connected to the temperature detection device and the compressor. The control device controls the speed and / or compression ratio of the compressor based on the detection result of the temperature detection device.

3. The low-temperature flue gas utilization system for painting workshops as described in claim 2, characterized in that, The hot water supplied to the water tank is used to clean the workpiece to be coated.

4. The low-temperature flue gas utilization system for painting workshops as described in claim 1, characterized in that, It also includes a low-pressure controller located between the gas-liquid separator and the compressor, and a high-pressure controller located between the compressor and the condenser. The low-pressure controller and the high-pressure controller each include a first pressure detector and a second pressure detector for detecting the intake pressure and exhaust pressure of the compressor. The control device is connected to the first pressure detector and the second pressure detector. The control device controls whether to cut off the power to the compressor based on the detection results of the first pressure detector and the second pressure detector.

5. The low-temperature flue gas utilization system for painting workshops as described in claim 1, characterized in that, The plurality of units are four units. The diversion device includes a main pipe with a rectangular cross-section and four branch pipes with rectangular cross-sections connected to the main pipe. The inlet of the main pipe is the diversion inlet, and the outlet of the four branch pipes is the diversion outlet. The four branch pipes have the same cross-sectional shape and are evenly and centrally symmetrically distributed.

6. The low-temperature flue gas utilization system for painting workshops as described in claim 5, characterized in that, The main pipeline is a straight cylindrical pipeline, and the branch pipeline includes a first straight cylindrical section connected to the main pipeline and a second straight cylindrical section whose axis forms an obtuse angle with the axis of the first straight cylindrical section.

7. The low-temperature flue gas utilization system for painting workshops as described in claim 1, characterized in that, The flue gas outlet of the evaporator is connected to the outlet end of the chimney.

8. The low-temperature flue gas utilization system for painting workshops as described in claim 7, characterized in that, The flue gas introduction device is an induced draft fan. The low-temperature flue gas utilization system in the painting workshop also includes a confluence device and a second control valve and a third control valve for controlling the connection or disconnection of the pipeline. The confluence device includes multiple confluence inlets connected to the flue gas outlets of each of the evaporators and a confluence outlet connected to the outlet end of the chimney. The second control valve is located on the pipeline between the induced draft fan and the inlet end of the chimney, and the third control valve is located on the pipeline between the confluence outlet and the outlet end of the chimney.

Images