Energy-saving heat exchange structure for textile printing and dyeing

Abstract

This invention relates to the field of textile printing and dyeing technology, specifically to an energy-saving heat exchange structure for textile printing and dyeing. It includes a heat exchange tank, an external heat exchange tube, a gas connection pipe, and a cold water heat exchange tube. The gas connection pipe connects the exhaust gas outlet of the external heat exchange tube to the lower part of the heat exchange tank. The heat exchange tank contains an inner heat exchange cylinder, and the outer shell of the inner heat exchange cylinder has a heat exchange jacket. After entering the heat exchange tank, the cold water heat exchange tube undergoes primary heat exchange through the heat exchange jacket before leaving the heat exchange tank and entering the external heat exchange tube for secondary heat exchange with the exhaust gas. The heat exchange tank also contains a gas stirring assembly. The exhaust gas is sprayed into the heat exchange tank through the gas stirring assembly to agitate the waste liquid. The exhaust gas enters the waste liquid for simultaneous gas washing. This achieves continuous recovery of waste heat from both the exhaust gas and the waste liquid, reducing the need for two separate heat exchange cycles and improving the utilization rate of the cold water heat exchange tube.

Description

Technical Field

[0001] This invention relates to the field of textile printing and dyeing technology, specifically to an energy-saving heat exchange structure for textile printing and dyeing. Background Technology

[0002] The textile dyeing and printing process typically involves dyeing, washing, drying, and setting, which generate a certain amount of high-temperature waste gas and wastewater. The waste gas not only carries a significant amount of heat but may also contain water vapor, particulate matter, and volatile pollutants; the wastewater similarly contains considerable residual heat and dye / chemical components. Directly discharging the waste gas and wastewater would not only waste thermal energy but also increase the load on subsequent waste gas purification and wastewater treatment.

[0003] Existing waste heat recovery devices in the dyeing and printing industry typically treat waste gas and wastewater separately through heat exchange. Specifically, a waste gas heat exchanger recovers heat from the waste gas, and a wastewater heat exchanger recovers heat from the wastewater. When the waste gas and wastewater heat exchange devices are independent, separate heat exchange pipelines, conveying equipment, and processing containers are required. This results in a large equipment footprint, complex piping connections, and the waste gas may still contain residual heat and pollutants after the initial heat exchange, necessitating additional gas scrubbing equipment for treatment. This leads to increased equipment investment and operating energy consumption.

[0004] In wastewater heat exchange processes, if wastewater relies primarily on its own gravity or conventional pipeline transport, problems such as short flow paths, uneven local flow velocities, and insufficient contact with heat exchange tubes can easily arise. While mechanical stirring mechanisms can improve wastewater flow, they increase power consumption, and prolonged contact with dyeing wastewater can lead to corrosion, scaling, and maintenance difficulties. Furthermore, some existing heat exchange devices struggle to adjust the flow velocity and residence time of wastewater within the heat exchange zone based on operating conditions such as temperature and flow rate, potentially resulting in insufficient heat exchange time or low treatment efficiency.

[0005] Therefore, there is a need for an energy-saving heat exchange structure for textile printing and dyeing that can recover the heat carried by waste gas and wastewater, while using the waste gas after heat exchange to perform jet agitation and scrubbing treatment on the wastewater, and can regulate the flow state of the wastewater in the heat exchange area, thereby improving the waste heat utilization rate and comprehensive treatment efficiency. Summary of the Invention

[0006] To address the above problems, this invention provides an energy-saving heat exchange structure for textile printing and dyeing.

[0007] The technical solution adopted by the present invention to solve its technical problem is: an energy-saving heat exchange structure for textile printing and dyeing, comprising a heat exchange tank, a waste gas heat exchange section and a wastewater heat exchange section, wherein the heat exchange tank is filled with wastewater and is equipped with a dosing box, characterized in that: the waste gas heat exchange section includes an external heat exchange pipe and a gas connecting pipe, the gas connecting pipe being connected between the waste gas outlet of the external heat exchange pipe and the lower part of the heat exchange tank; the wastewater heat exchange section includes a cold water heat exchange pipe; the heat exchange tank is equipped with a heat exchange inner cylinder, and a heat exchange jacket is provided inside the outer shell of the heat exchange inner cylinder; after the cold water heat exchange pipe enters the heat exchange tank, it undergoes primary heat exchange through the heat exchange jacket and then leaves the heat exchange tank, and then enters the external heat exchange pipe to undergo secondary heat exchange with the waste gas; The heat exchange tank is equipped with a gas stirring assembly located below the surface of the wastewater. The gas stirring assembly is connected to a gas connecting pipe. After secondary heat exchange, the waste gas is sprayed into the heat exchange tank through the gas stirring assembly to agitate the wastewater. The waste gas and wastewater exchange heat and are simultaneously washed.

[0008] As an optimization, the gas stirring assembly includes a booster pump, a connecting hose, and a gas nozzle. The booster pump is connected to a gas connecting pipe, and the connecting hose is connected between the gas nozzle and the gas connecting pipe. The connecting hose is equipped with a one-way valve. A swing motor is arranged on the lower inner side of the heat exchange tank. A connecting arm is installed on the output shaft of the swing motor, and the outer end of the connecting arm is connected to the gas nozzle.

[0009] As an optimization, the cold water heat exchange tube includes a first heat exchange section and a second heat exchange section. The first heat exchange section is located in the heat exchange jacket. A gas heat exchange cavity is opened inside the outer heat exchange tube. The second heat exchange section passes horizontally through the gas heat exchange cavity. The gas heat exchange cavity is equipped with an inlet pipe. Exhaust gas enters the gas heat exchange cavity through the inlet pipe and contacts the surface of the second heat exchange section for secondary heat exchange. Then it is discharged through the gas connection pipe. The lower part of the second heat exchange section is evenly equipped with several heat exchange fins. The bottom of the external heat exchange tube is inclined. The bottom of the external heat exchange tube is connected to a drain pipe. The drain pipe (16) is connected to the lowest point of the inclined bottom wall.

[0010] As an optimization, the outer wall of the heat exchange inner cylinder is provided with a liquid inlet and the inner wall is provided with a liquid outlet. Wastewater enters the heat exchange jacket through the liquid inlet and comes into contact with the cold water heat exchange tube for primary heat exchange. It then enters the heat exchange inner cylinder through the liquid outlet and is discharged. The liquid inlet and the liquid outlet are offset circumferentially around the axis of the heat exchange inner cylinder and are spaced apart along the axis. The flow direction of cold water in the first heat exchange section is opposite to the flow direction of wastewater in the heat exchange jacket. The opening of the liquid inlet is tilted towards the direction of the liquid outlet.

[0011] As an optimization, a stirring chamber is formed between the inner wall of the heat exchange tank and the outer wall of the inner heat exchange cylinder. A wastewater inlet pipe and a waste gas outlet pipe are provided at the top of the heat exchange tank. A wastewater outlet pipe is connected to the bottom of the inner heat exchange cylinder. The lower end of the wastewater outlet pipe extends out of the bottom of the heat exchange tank. The dosing box outlet, wastewater inlet pipe, and wastewater outlet pipe are all connected to the upper part of the stirring chamber. The outer end of the wastewater outlet pipe is connected to a sedimentation device.

[0012] As an optimization, the thickness of the heat exchange jacket is greater than the outer diameter of the cold water heat exchange tube, the opening height of the liquid inlet and the liquid outlet is the same as that of the heat exchange jacket, and the arc length of the liquid inlet is not less than 1 / 4 of the outer diameter of the heat exchange inner cylinder.

[0013] As an optimization, the liquid inlet penetrates the outer wall of the heat exchange inner cylinder and has an outer opening toward the stirring chamber and an inner opening toward the heat exchange jacket; the outer opening and the inner opening are offset in the circumferential direction around the axis of the heat exchange inner cylinder, so that the center line of the liquid inlet extends radially and circumferentially from the outer opening to the inner opening. The projection of the centerline of the liquid inlet onto a plane perpendicular to the axis of the heat exchange inner cylinder is arc-shaped.

[0014] As an optimization, the gas nozzle can swing between a first jet position and a second jet position; in the first jet position, the gas outlet direction of the gas nozzle has a circumferential component that is the same as the preset circumferential flow direction of the wastewater entering the inlet; in the second jet position, the gas outlet direction of the gas nozzle has a circumferential component that is opposite to the preset circumferential flow direction.

[0015] As an optimization, the exhaust gas outlet pipe is connected to a finned heat exchanger, and the clean water outlet of the sedimentation equipment is connected to a plate heat exchanger.

[0016] The beneficial effects of this plan are as follows: This application enables the cold water heat exchange tubes to pass sequentially through the heat exchange jacket and the outer heat exchange tubes inside the heat exchange tank. The first heat exchange section is used for primary heat exchange to absorb the heat carried by the wastewater, and the second heat exchange section is used for secondary heat exchange to absorb the heat carried by the exhaust gas. This achieves continuous recovery of waste heat from both the exhaust gas and the waste water, reducing the need for two separate independent heat exchange cycles and improving the utilization rate of the cold water heat exchange tubes.

[0017] After secondary heat exchange within the external heat exchange tubes, the exhaust gas is transported via a gas connection pipe to a gas agitation component located below the wastewater surface, where it is sprayed into the wastewater in the form of bubbles. As the exhaust gas rises, it drives the wastewater flow, reducing reliance on independent mechanical agitation mechanisms while ensuring sufficient contact between the exhaust gas and wastewater. This allows for further absorption of heat from the exhaust gas, raising the wastewater temperature and improving the primary heat exchange efficiency. Simultaneously, wastewater agitation and exhaust gas scrubbing are achieved.

[0018] A stirring chamber is formed between the inner wall of the heat exchange tank and the outer wall of the inner heat exchange cylinder. A heat exchange jacket is formed between the inner and outer walls of the inner heat exchange cylinder. Wastewater, after being agitated by jet injection, enters the heat exchange jacket through the inlet and flows along the jacket to the outlet. The inlet and outlet are staggered circumferentially and spaced apart axially, which prolongs the flow path of the wastewater within the heat exchange jacket. At the same time, by making the wastewater flow in the opposite direction to the cold water in the first heat exchange section, it is beneficial to maintain the heat exchange temperature difference and improve the wastewater waste heat recovery effect.

[0019] The outer and inner openings of the liquid inlet are offset along the circumference of the heat exchange inner cylinder, and the center line of the liquid inlet extends radially and circumferentially, with its projection being arc-shaped. This allows the wastewater to obtain a circumferential velocity component when entering the heat exchange jacket, which is beneficial for guiding the wastewater to flow circumferentially along the heat exchange inner cylinder, reducing the possibility of wastewater directly impacting local heat exchange tubes and the formation of flow dead zones within the heat exchange jacket, and improving the uniformity of contact between wastewater and cold water heat exchange tubes.

[0020] The gas nozzle can oscillate between a first and a second jetting position. When the gas outlet direction is the same as the preset circumferential flow direction of the wastewater, it can accelerate the wastewater into the heat exchange jacket, increasing the wastewater treatment flow rate. When the gas outlet direction is opposite to the preset circumferential flow direction, it can obstruct the circumferential flow of the wastewater, reducing the wastewater velocity and prolonging the residence time of the wastewater in the heat exchange jacket. Therefore, the treatment efficiency and heat exchange time can be adjusted according to the wastewater temperature and heat exchange requirements.

[0021] The heat exchange fins in the second heat exchange section increase the effective heat exchange area between the exhaust gas and the cold water heat exchange tubes, further improving the heat exchange effect. The external heat exchange tubes have an inclined bottom wall, and the drain pipe is located at the lowest point of the inclined bottom wall, which facilitates the discharge of liquid and deposited impurities formed by the condensation of exhaust gas, reducing the possibility of dirt accumulating inside the external heat exchange tubes and affecting the heat exchange efficiency. Attached Figure Description

[0022] Figure 1 This is an isometric view of the present invention.

[0023] Figure 2 This is a schematic diagram of the bottom axial side of the present invention.

[0024] Figure 3 This is a schematic diagram of the external heat exchanger tube of the present invention from the left.

[0025] Figure 4 For the present invention Figure 3 A schematic diagram of the AA cross-section structure.

[0026] Figure 5 This is a schematic front view of the heat exchange tank of the present invention.

[0027] Figure 6 For the present invention Figure 5 A schematic diagram of the BB cross-section structure.

[0028] Figure 7 For the present invention Figure 5 A schematic diagram of the CC cross-section structure.

[0029] Figure 8 This is a schematic diagram of the gas stirring assembly of the present invention from the axial side.

[0030] Figure 9 This is a schematic diagram showing the location and structure of the waste gas heat exchange section and the wastewater heat exchange section of the present invention.

[0031] Figure 10 This is a schematic diagram of the connection structure between the wastewater heat exchange section and the heat exchange inner cylinder of the present invention.

[0032] Figure 11 This is a diagram of the heat exchange system of the present invention.

[0033] The components are as follows: 1. Heat exchange tank; 2. External heat exchange tube; 3. Gas connection pipe; 4. Cold water heat exchange tube; 5. Heat exchange inner cylinder; 6. Heat exchange jacket; 7. Liquid inlet; 8. Liquid outlet; 9. Booster pump; 10. Connecting hose; 11. Gas nozzle; 12. One-way valve; 13. Swing motor; 14. Gas heat exchange chamber; 15. Heat exchange fins; 16. Sewage pipe; 17. Stirring chamber; 18. Wastewater inlet pipe; 19. Waste gas outlet pipe; 20. Wastewater outlet pipe; 21. Dosing box. Detailed Implementation

[0034] like Figures 1-10 As shown, this embodiment provides an energy-saving heat exchange structure for textile printing and dyeing, including a heat exchange tank 1, an external heat exchange pipe 2, a gas connection pipe 3, a cold water heat exchange pipe 4, a heat exchange inner cylinder 5, a gas stirring assembly, and a dosing box 21. The heat exchange tank 1 is used to contain printing and dyeing wastewater. The heat exchange inner cylinder 5 cooperates with the cold water heat exchange pipe 4 to perform primary heat exchange on the wastewater. The external heat exchange pipe 2 is used to perform secondary heat exchange on the cold water and absorb heat from the waste gas. The waste gas that has undergone secondary heat exchange continues to enter the heat exchange tank 1, where it completes jet stirring, gas washing, and further heat exchange between gas and liquid in the wastewater. This allows the waste gas treatment path, wastewater treatment path, and cold water heat absorption path to be interconnected in the same device.

[0035] The materials, specifications, power, models, and dimensions listed in this embodiment are for illustrating an feasible engineering configuration and do not constitute a limitation on the scope of protection. In actual manufacturing, the dimensions and equipment parameters can be adjusted proportionally according to the exhaust gas flow rate, wastewater treatment volume, medium temperature, acidity, alkalinity, and corrosivity. Alternatively, equivalent materials and equipment with the same temperature resistance, corrosion resistance, and heat transfer performance can be selected, which will not be elaborated further here.

[0036] like Figure 1 As shown, heat exchange tank 1 is a vertical cylindrical atmospheric pressure tank. Its cylinder, top cover, and bottom plate can be made of SUS304 stainless steel. For dyeing and printing wastewater with high chloride ion content or high acidity / alkalinity, SUS316L stainless steel can be used, or a carbon steel tank lined with PTFE and a glass flake anti-corrosion layer can be used. For medium-scale treatment, the tank wall thickness can be selected as 3-8mm. The top cover and cylinder can be detachably connected by flanges and bolts, with PTFE or fluororubber gaskets installed between the flanges. Continuous welding can be used in areas where frequent disassembly is not required, and the welds should be pickled, passivated, and inspected for airtightness. Support legs or a skirt can be installed at the bottom of heat exchange tank 1 to create installation space for the wastewater outlet pipe 20 and the drain valve.

[0037] like Figure 7 As shown, the heat exchange inner cylinder 5 is coaxially or substantially coaxially arranged with the heat exchange tank 1 and is fixed inside the heat exchange tank 1 by upper and lower support rings or radial support rods. A stirring chamber 17 is formed between the inner wall of the heat exchange tank 1 and the outer wall of the heat exchange inner cylinder 5. The heat exchange inner cylinder 5 consists of an outer cylinder wall and an inner cylinder wall, with a sealed annular heat exchange jacket 6 between the inner and outer cylinder walls. The heat exchange inner cylinder 5 is made of SUS316L stainless steel, and the inner and outer cylinder walls can be sealed by welding with annular end plates. The weld is continuously welded using argon arc welding to prevent unexpected short-flow between the wastewater in the heat exchange jacket 6 and the inner cavity of the heat exchange inner cylinder 5. The radial thickness of the heat exchange jacket 6 is greater than the outer diameter of the cold water heat exchange tube 4, and preferably a 5-20 mm flow gap is maintained between the outer wall of the cold water heat exchange tube 4 and the jacket wall to allow wastewater to pass through both sides of the heat exchange tube.

[0038] like Figure 1 and Figure 7 As shown, the top of the heat exchange tank 1 is equipped with a wastewater inlet pipe 18 and an exhaust gas outlet pipe 19. The outlet of the dosing box 21, the wastewater inlet pipe 18, and the exhaust gas outlet pipe 19 are all connected to the upper part of the stirring chamber 17. The wastewater inlet pipe 18 and the exhaust gas outlet pipe 19 can be connected to the top cover by flanges, quick-connect fittings, or welded sleeves, and corrosion-resistant valves are installed at the pipe openings. The exhaust gas outlet pipe 19 is kept connected to the subsequent induced draft or tail gas treatment pipeline to keep the heat exchange tank 1 under normal pressure or slightly negative pressure. The bottom of the heat exchange inner cylinder 5 is connected to the wastewater outlet pipe 20. The wastewater outlet pipe 20 is equipped with a welded sleeve and a sealing structure at the position where it passes through the bottom of the heat exchange tank 1, and its outer end is connected to the sedimentation equipment through a flange and a control valve.

[0039] like Figure 1 and Figure 7 As shown, the cold water heat exchanger tube 4 is a continuous heat exchange pipeline, including primary heat exchange located in the heat exchange jacket 6 and secondary heat exchange located in the outer heat exchanger tube 2. The cold water heat exchanger tube 4 can be made of SUS304 or SUS316L seamless steel pipe, with an outer diameter of 20-40mm and a wall thickness of 1.5-3mm. For applications with low corrosivity and high thermal conductivity requirements, copper alloy pipe with an external anti-corrosion coating can also be used. Welded sleeves, packing seals, or metal corrugated compensation structures are installed where the cold water heat exchanger tube 4 passes through the outer heat exchanger tube 2 and the shell of the heat exchange tank 1 to absorb thermal expansion and contraction and prevent gas or liquid leakage. Flanges or unions are installed at its exposed cold water inlet and outlet for easy connection to circulating water pumps, hot water storage tanks, or production hot water pipelines.

[0040] The first heat exchange section is arranged circumferentially within the heat exchange jacket 6 along the inner heat exchange cylinder 5. It can be made into a spiral coil, an arc coil, or a multi-pass serpentine tube, and is fixed to the inner cylinder wall at intervals by stainless steel pipe clamps. The second heat exchange section passes horizontally through the gas heat exchange chamber 14, allowing high-temperature waste gas to flow over its outer surface and transfer heat to the cold water inside the tube. The flow direction of the cold water in the first heat exchange section is opposite to the overall flow direction of the waste water in the heat exchange jacket 6, creating counter-current heat exchange between the hot and cold media to maintain the temperature difference along the flow path. Thus, the same cold water pipeline first absorbs heat from the waste water, and after its temperature is initially raised, it absorbs heat from the waste gas, further increasing the temperature of the heat exchange cold water. Moreover, the temperature of the waste water also increases after contacting the waste gas, enabling the series recovery of two types of waste heat. When it is necessary to control the outlet water temperature, a flow regulating valve or a variable frequency circulating pump can be installed at the cold water inlet.

[0041] like Figure 4 As shown, the external heat exchange tube 2 can be made into a cylindrical or rectangular shell, forming a closed gas heat exchange chamber 14 inside. One end of the gas heat exchange chamber 14 is provided with an inlet pipe that connects to the dyeing and printing dryer, setting machine, or main gas collection pipe, and the other end forms an exhaust gas outlet that connects to the gas connection pipe 3. The external heat exchange tube 2 is made of SUS304 or SUS316L stainless steel. The inlet pipe, exhaust gas outlet, and inspection port are connected by flanges, and the flange gaskets are made of expanded polytetrafluoroethylene or high-temperature resistant fluororubber. After the exhaust gas enters the gas heat exchange chamber 14, it flows around the second heat exchange section and the heat exchange fins 15. The sensible heat of the exhaust gas and part of the latent heat of condensation of water vapor are transferred to the cold water inside the tube.

[0042] like Figure 4As shown, several heat exchange fins 15 are spaced apart along the length of the tube at the bottom of the second heat exchange section. The heat exchange fins 15 can be made of 0.5-1.5mm thick SUS304 or SUS316L thin plates, with a fin spacing of 10-30mm, and are thermally connected to the outer wall of the second heat exchange section by brazing, expansion, or continuous welding; aluminum alloy fins with anti-corrosion treatment can also be used when the corrosion is low. The bottom wall of the external heat exchange tube 2 forms a slope of 3°-10° towards the drain pipe 16. The drain pipe 16 is located at the lowest point and can be made of DN25-DN50 stainless steel pipe. A ball valve or drain valve is installed downstream of it, so that the waste gas condensate, dust and adhering impurities can be discharged by gravity, reducing the possibility of deposits covering the heat exchange surface.

[0043] like Figure 1 and Figure 8 As shown, the exhaust gas outlet of the external heat exchanger 2, the gas connection pipe 3, the booster pump 9, the connecting hose 10, the one-way valve 12, and the gas nozzle 11 sequentially form a gas path for exhaust gas to pass through. The gas connection pipe 3 can be made of SUS316L stainless steel or a composite pipe lined with polytetrafluoroethylene, and is connected to the external heat exchanger 2 and the booster pump 9 by a flange. The connecting hose 10 is a polytetrafluoroethylene hose with a stainless steel braided outer layer, and the nominal diameter can be selected from DN15 to DN32 to allow the gas nozzle 11 to swing within a certain angle range. The one-way valve 12 is directed towards the gas nozzle 11 to prevent wastewater from flowing back along the connecting hose 10 when the machine is stopped; the one-way valve 12 can be an H12W type stainless steel internal thread check valve, a corrosion-resistant duckbill valve, or a low-opening pressure check valve with the same function.

[0044] The booster pump 9 is used to overcome the static pressure of wastewater, pipeline resistance, and nozzle resistance. For medium-sized plants, a 2RB series corrosion-resistant vortex pump or a corrosion-resistant gas booster pump with equivalent performance can be selected, with an example flow rate of 80-300 m³ / h and a pressure boost of 10-30 kPa, and the air supply is adjusted by a frequency converter; specific parameters are determined by calculation based on the liquid level and the total orifice area of ​​the nozzle. The gas nozzle 11 can be a SUS316L porous tube nozzle or a sintered aeration head, with a nozzle diameter of 2-6 mm. The gas nozzle 11 is located below the lowest working liquid level, preferably 100-300 mm below the lowest working liquid level, so that the waste gas forms dispersed bubbles and fully contacts the wastewater during the ascent, realizing jet agitation, gas washing, and gas-liquid heat exchange.

[0045] like Figure 1 and Figure 8As shown, the oscillating motor 13 drives the gas nozzle 11 to rotate or oscillate reciprocally via the connecting arm. To prevent the motor from being submerged in wastewater for extended periods, the oscillating motor 13 can be installed in a sealed motor compartment at the lower inner side of the heat exchange tank 1, or installed on the outer wall of the heat exchange tank 1 with the output shaft extending into the tank through a sealed bushing. A silicon carbide mechanical seal and a fluororubber auxiliary seal can be used between the output shaft and the tank wall, and the connecting arm and fasteners are made of SUS316L stainless steel. The oscillating motor 13 can be a 24V or 48V low-speed DC geared motor with IP68 protection rating, or a 60 series or 80 series servo geared motor. The example output speed is 1-10 r / min and the output torque is 5-30 N·m. Limit switches or angle sensors are installed at both ends of the motor to limit the first and second jet positions.

[0046] like Figure 6 As shown, the gas nozzle 11 can be positioned adjacent to the liquid inlet 7. In the first jet position, the nozzle's outlet direction has a circumferential component identical to the preset circumferential flow direction of the wastewater entering the liquid inlet 7. The bubble jet propels the wastewater, increasing the inlet velocity and treatment throughput. When the gas nozzle 11 rotates to the other direction, reaching the second jet position, the nozzle's outlet direction has a circumferential component opposite to the preset circumferential flow direction. The bubble jet impedes the circumferential flow, reducing the inlet velocity and prolonging the wastewater's residence time within the heat exchange jacket 6. The nozzle tilt angle, the booster pump 9 frequency, and the chilled water flow rate can be adjusted individually or linked together based on temperature signals. Figure 6 The image shows the first jet position.

[0047] like Figure 6 As shown, the liquid inlet 7 penetrates the outer wall of the heat exchange inner cylinder 5 and has an external opening toward the stirring chamber 17 and an internal opening toward the heat exchange jacket 6. The external and internal openings are circumferentially offset around the axis of the heat exchange inner cylinder 5, so that the centerline of the liquid inlet 7 extends radially and circumferentially from the external opening to the internal opening, and its projection on the plane perpendicular to the axis of the heat exchange inner cylinder 5 is arc-shaped. The liquid inlet 7 can be formed by welding an arc-shaped guide tube to the outer cylinder wall, or it can be formed by stamping, casting, or machining an arc-shaped guide plate; the inner wall of the flow channel is preferably polished smooth to reduce the adhesion of dye particles and fiber impurities.

[0048] like Figure 6As shown, the opening of the inlet 7 is inclined towards the outlet 8. The inlet 7 and outlet 8 are offset circumferentially and spaced apart along the axis of the inner heat exchange cylinder 5. The axial opening height of the inlet 7 and outlet 8 can be the same as the effective height of the heat exchange jacket 6. The arc length of the inlet 7 measured circumferentially along the outer cylinder wall is not less than one-quarter of the outer diameter of the inner heat exchange cylinder 5, so as to reduce the inlet resistance and disperse the wastewater into the jacket along the height direction. After passing through the arc-shaped inlet 7, the wastewater obtains a circumferential velocity component and flows along the heat exchange jacket 6 around the inner heat exchange cylinder 5 to the outlet 8. In conjunction with the reverse cold water flow in the first heat exchange section, the flow path can be extended, short-circuiting and dead zones can be reduced, and the contact uniformity between the wastewater and the outer wall of the cold water heat exchange tube 4 can be improved.

[0049] like Figure 7 As shown, the dosing box 21 can be made of PP-H, polyethylene, or SUS316L material, and its outlet is connected to the upper part of the stirring chamber 17 via a corrosion-resistant hose. The reagent can be added by gravity or by configuring a JXM or JX series diaphragm metering pump, with an example metering range of 0.1-10 L / h, for adding neutralizing agents, coagulants, or other treatment agents as needed for the process. Specific reagent selection will not be elaborated here. Because the exhaust gas bubbles continuously agitate the wastewater, the added reagent can disperse quickly within the stirring chamber 17.

[0050] The heat exchange tank 1 can also be equipped with a magnetic float level gauge or a submersible level sensor, and PT100 temperature sensors and flow meters can be installed at the exhaust gas inlet, exhaust gas outlet, wastewater inlet, wastewater outlet, and cold water inlet and outlet. The controller can be a small PLC, such as an S7-200 SMART equivalent controller, and the booster pump 9 and the swing motor 13 can be controlled by a frequency converter.

[0051] After being washed by wastewater in the stirring chamber 17, the exhaust gas is discharged from the exhaust gas outlet pipe 19 and can enter a stainless steel finned tube heat exchanger for further waste heat recovery; a condensate outlet is preferably provided at the bottom of the heat exchanger. The wastewater discharged through the heat exchange inner cylinder 5 and the wastewater outlet pipe 20 enters a sedimentation device to separate flocs, particulate matter, or other sediments; the purified water after sedimentation can enter a BR0.1, BR0.2 series, or equivalent detachable plate heat exchanger for further heat exchange with makeup water or process water. The plates of the plate heat exchanger are preferably made of SUS316L, and the gaskets can be made of EPDM or chemically resistant fluororubber. The specific heat exchange area of ​​the subsequent heat exchangers is determined based on the exhaust gas volume, purified water flow rate, and target outlet temperature.

[0052] like Figure 11The temperature of the wastewater is about 40-60℃, the temperature of the exhaust gas is about 120-200℃, and the temperature of the cold water is about 10-25℃. When the air temperature is high, the temperature of the cold water also increases. During operation, cold water flows within the cold water heat exchange tube 4, while wastewater enters the heat exchange jacket 6, where it comes into counter-current contact with the first heat exchange section, forming primary heat exchange. After primary heat exchange, the cold water reaches a temperature of 30-50℃. The wastewater then enters the inner cavity of the heat exchange inner cylinder 5 through the outlet 8 and exits through the wastewater outlet pipe 20. The cold water continues to rise into the outer heat exchange tube 2, where it contacts the second heat exchange section and heat exchange fins 15 to complete secondary heat exchange. At this point, the cold water temperature can reach 80-95℃. After heat exchange, the exhaust gas is injected below the wastewater surface through the gas nozzle 11 by the booster pump 9. As the bubbles rise, they transfer the remaining heat to the wastewater, further increasing its temperature. The wastewater absorbs or entrains some water-soluble pollutants and particulate matter from the exhaust gas, while simultaneously creating pneumatic agitation, further promoting the flow of wastewater inside the heat exchange tank 1. Figure 1 For example, the heat exchange cold water flows from bottom to top, and the exhaust gas flows from top to bottom into heat exchange tank 1, thus forming a synergistic heat transfer path of "primary heat exchange of wastewater to cold water - secondary heat exchange of exhaust gas to cold water - contact heat exchange and gas washing of exhaust gas to wastewater".

[0053] When the wastewater flow rate of the production line is large or the instantaneous treatment capacity needs to be increased, the gas nozzle 11 is switched to the first jet position, and the frequency of the booster pump 9 is appropriately increased to propel the wastewater into the heat exchange jacket 6. When the wastewater temperature is high, the cold water flow rate is low, or the degree of heat exchange per pass needs to be increased, the gas nozzle 11 is switched to the second jet position to slow down the wastewater flow with the reverse circumferential component, and the opening of the wastewater outlet valve is appropriately reduced to prolong the heat exchange residence time. This adjustment does not simply change the stirring intensity, but rather uses the coordination between the bubble jet direction and the arc-shaped liquid inlet channel to change the circumferential momentum of the wastewater.

[0054] How to use: Step S1: Pre-operation inspection. Confirm that the external heat exchanger tube 2, gas connection tube 3, cold water heat exchanger tube 4, heat exchange jacket 6, and all flanges are properly sealed; open the drain pipe 16 to discharge residual liquid for a short time, then close the drain valve; check the installation direction of the one-way valve 12 and the swing range of the gas nozzle 11; and confirm that the exhaust gas outlet pipe 19 and the sedimentation equipment are in usable condition.

[0055] Step S2: Establish cold water circulation. First, start the cold water circulation pump to allow cold water to flow through the first and second heat exchange sections in sequence, expelling air from the pipes. Adjust the circulation pump frequency or cold water valve according to the cold water inlet and outlet temperatures and the design flow rate. After confirming that there are no leaks in the cold water heat exchange pipe 4, introduce the high-temperature medium.

[0056] Step S3: Add wastewater and chemicals. Dyeing wastewater is introduced into the mixing chamber 17 through the wastewater inlet pipe 18, raising the liquid level above the gas nozzle 11 and reaching the predetermined working level. Based on the wastewater's pH, turbidity, or subsequent sedimentation requirements, appropriate treatment chemicals are added through the dosing box 21. The valve on the wastewater outlet pipe 20 is kept at an opening sufficient to maintain a stable liquid level.

[0057] Step S4: Perform primary heat exchange for wastewater. The wastewater in the stirring chamber 17 enters the heat exchange jacket 6 after obtaining the circumferential velocity component through the arc-shaped inlet 7, and flows along the jacket to the outlet 8, which is opposite to the overall flow direction of the cold water. The wastewater transfers heat to the cold water in the first heat exchange section, and then enters the inner cavity of the heat exchange inner cylinder 5, and is discharged into the sedimentation equipment through the wastewater outlet pipe 20, finally obtaining relatively clean crystal water.

[0058] Step S5: Perform waste gas heat exchange. High-temperature waste gas from the dyeing and finishing drying, setting, or gas collection pipeline is introduced into the gas heat exchange chamber 14 through the inlet pipe, so that the waste gas flows through the second heat exchange section and heat exchange fins 15; condensate and deposited impurities are collected along the inclined bottom wall and periodically discharged from the drain pipe 16.

[0059] Step S6: Perform jet agitation, gas washing, and further heat exchange. Start the booster pump 9. The exhaust gas enters the gas nozzle 11 through the gas connection pipe 3, the connecting hose 10, and the one-way valve 12, forming bubbles below the wastewater surface. The bubbles drive the wastewater circulation, allowing the exhaust gas to directly contact the wastewater for washing and heat exchange, further increasing the wastewater temperature. The treated exhaust gas is discharged from the exhaust gas outlet pipe 19 at the top of the heat exchange tank 1, resulting in relatively clean gas. The clean gas then enters the finned heat exchanger for further heat exchange.

[0060] Step S7: Adjust the processing status. When it is necessary to increase the processing throughput, control the swing motor 13 to position the gas nozzle 11 in the first jet position; when it is necessary to extend the heat exchange time, position the gas nozzle 11 in the second jet position. The controller can adjust the nozzle position, the frequency of the booster pump 9, the cold water flow rate, and the opening of the wastewater outlet valve in conjunction with the wastewater outlet temperature, the cold water outlet temperature, or the temperature difference between the two. The waste gas can continue to recover heat in the finned heat exchanger downstream of the waste gas outlet pipe 19, and the settled clear water can recover waste heat again in the plate heat exchanger.

[0061] Step S8: Shutdown and Cleaning. When shutting down, first cut off the high-temperature exhaust gas, then stop the booster pump 9, and maintain cold water circulation for a period of time to remove residual heat; subsequently, turn off the cold water circulation and empty the heat exchange tank 1 and heat exchange jacket 6. Depending on the amount of sediment, flush with clean water through the wastewater inlet pipe 18 or the inspection port. Open the drain pipe 16 and wastewater outlet pipe 20 to discharge the cleaning fluid, and check whether the inlet 7, outlet 8, heat exchange fins 15, and gas nozzle 11 are blocked.

[0062] This application utilizes the same cold water heat exchange tube 4 to sequentially construct the first heat exchange section on the wastewater side and the second heat exchange section on the waste gas side. The waste gas, after undergoing secondary heat exchange, continues to serve as the driving medium for wastewater jet agitation and scrubbing, thus creating a seamless connection between waste gas waste heat recovery, wastewater waste heat recovery, pneumatic agitation, and gas-liquid purification in the medium flow path. This combination allows for the reuse of residual heat and flow energy of the waste gas, with each component exhibiting a mutually reinforcing functional relationship.

[0063] Furthermore, the arc-shaped inlet 7 imparts a circumferential velocity component to the wastewater. The circumferentially and axially misaligned inlet 7 and outlet 8 extend the interlayer flow path, forming counter-current heat exchange with the wastewater in the first heat exchange section. Meanwhile, the oscillating gas nozzle 11 adjacent to the inlet 7 can selectively boost or impede this circumferential flow. Together, these structures achieve active regulation of the wastewater flow rate and heat exchange residence time, enabling the device to switch between higher throughput and more sufficient heat exchange, forming the effect of "arc-shaped flow guidance - counter-current heat exchange - bidirectional jet regulation".

[0064] The above-described specific embodiments are merely specific examples of the present invention. The patent protection scope of the present invention includes, but is not limited to, the product form and style of the above-described specific embodiments. Any energy-saving heat exchange structure for textile printing and dyeing that conforms to the claims of the present invention, and any appropriate changes or modifications made to it by a person skilled in the art, shall fall within the patent protection scope of the present invention.

Claims

1. An energy-saving heat exchange structure for textile printing and dyeing, comprising a heat exchange tank (1), a waste gas heat exchange section, and a wastewater heat exchange section, wherein the interior of the heat exchange tank (1) is filled with wastewater, and the heat exchange tank (1) is equipped with a dosing box (21), characterized in that: The waste gas heat exchange section includes an external heat exchange pipe (2) and a gas connection pipe (3). The gas connection pipe (3) is connected between the waste gas outlet of the external heat exchange pipe (2) and the lower part of the heat exchange tank (1). The waste water heat exchange section includes a cold water heat exchange pipe (4). The heat exchange tank (1) is equipped with a heat exchange inner cylinder (5). A heat exchange jacket (6) is opened in the outer shell of the heat exchange inner cylinder (5). After the cold water heat exchange pipe (4) enters the heat exchange tank, it undergoes primary heat exchange through the heat exchange jacket (6) and then leaves the heat exchange tank (1) before entering the external heat exchange pipe (2) to undergo secondary heat exchange with the waste gas. The heat exchange tank (1) is equipped with a gas stirring assembly located below the surface of the wastewater. The gas stirring assembly is connected to a gas connecting pipe (3). After secondary heat exchange, the waste gas is sprayed into the heat exchange tank (1) through the gas stirring assembly to stir the wastewater. The waste gas and wastewater exchange heat and are washed simultaneously.

2. The energy-saving heat exchange structure for textile printing and dyeing according to claim 1, characterized in that: The gas stirring assembly includes a booster pump (9), a connecting hose (10), and a gas nozzle (11). The booster pump (9) is connected to a gas connecting pipe (3). The connecting hose (10) is connected between the gas nozzle (11) and the gas connecting pipe (3). The connecting hose (10) is equipped with a one-way valve (12). A swing motor (13) is arranged on the lower inner side of the heat exchange tank (1). A connecting arm is installed on the output shaft of the swing motor (13), and the outer end of the connecting arm is connected to the gas nozzle (11).

3. The energy-saving heat exchange structure for textile printing and dyeing according to claim 2, characterized in that: The cold water heat exchange tube (4) includes a first heat exchange section and a second heat exchange section. The first heat exchange section is located in the heat exchange jacket (6). The outer heat exchange tube (2) has a gas heat exchange chamber (14) inside. The second heat exchange section passes horizontally through the gas heat exchange chamber (14). The gas heat exchange chamber (14) is equipped with an air inlet pipe. Waste gas enters the gas heat exchange chamber (14) through the air inlet pipe and contacts the surface of the second heat exchange section for secondary heat exchange. Then it is discharged through the gas connection pipe (3). The lower part of the second heat exchange section is evenly equipped with several heat exchange fins (15). The bottom of the external heat exchange tube (2) is inclined. The bottom of the external heat exchange tube (2) is connected to a drain pipe (16). The drain pipe (16) is connected to the lowest point of the inclined bottom wall.

4. The energy-saving heat exchange structure for textile printing and dyeing according to claim 3, characterized in that: The outer wall of the heat exchange inner cylinder (5) is provided with an inlet (7) and the inner wall is provided with an outlet (8). Wastewater enters the heat exchange jacket (6) through the inlet (7) and comes into contact with the cold water heat exchange tube (4) for primary heat exchange. It then enters the heat exchange inner cylinder (5) through the outlet (8) and is discharged. The liquid inlet (7) and the liquid outlet (8) are offset in the circumferential direction around the axis of the heat exchange inner cylinder (5) and are spaced apart along the axis. The flow direction of cold water in the first heat exchange section is opposite to the flow direction of waste water in the heat exchange jacket (6). The opening of the inlet (7) is tilted toward the outlet (8).

5. The energy-saving heat exchange structure for textile printing and dyeing according to claim 4, characterized in that: A stirring chamber (17) is formed between the inner wall of the heat exchange tank (1) and the outer wall of the heat exchange inner cylinder (5). A wastewater inlet pipe (18) and a waste gas outlet pipe (19) are arranged at the top of the heat exchange tank (1). A wastewater outlet pipe (20) is connected to the bottom of the heat exchange inner cylinder (5). The lower end of the wastewater outlet pipe (20) extends out of the bottom of the heat exchange tank (1). The outlet of the dosing box (21), the wastewater inlet pipe (18), and the wastewater outlet pipe (20) are all connected to the upper part of the stirring chamber (17). The outer end of the wastewater outlet pipe (20) is connected to a sedimentation device.

6. The energy-saving heat exchange structure for textile printing and dyeing according to claim 4, characterized in that: The thickness of the heat exchange jacket (6) is greater than the outer diameter of the cold water heat exchange tube (4). The opening height of the liquid inlet (7) and the liquid outlet (8) is the same as that of the heat exchange jacket (6). The opening arc length of the liquid inlet (7) is not less than 1 / 4 of the outer diameter of the heat exchange inner cylinder (5).

7. The energy-saving heat exchange structure for textile printing and dyeing according to claim 5, characterized in that: The liquid inlet (7) penetrates the outer wall of the heat exchange inner cylinder (5) and has an outer opening toward the stirring chamber (17) and an inner opening toward the heat exchange jacket (6); the outer opening and the inner opening are offset in the circumferential direction around the axis of the heat exchange inner cylinder (5), so that the center line of the liquid inlet (7) extends radially and circumferentially from the outer opening to the inner opening. The projection of the centerline of the liquid inlet (7) onto a plane perpendicular to the axis of the heat exchange inner cylinder (5) is arc-shaped.

8. The energy-saving heat exchange structure for textile printing and dyeing according to claim 4, characterized in that: The gas nozzle (11) is oscillating between a first jet position and a second jet position; in the first jet position, the gas outlet direction of the gas nozzle (11) has a circumferential component that is the same as the preset circumferential flow direction of the wastewater entering the inlet (7); in the second jet position, the gas outlet direction of the gas nozzle (11) has a circumferential component that is opposite to the preset circumferential flow direction.

9. The energy-saving heat exchange structure for textile printing and dyeing according to claim 5, characterized in that: The exhaust gas outlet pipe (19) is connected to a finned heat exchanger, and the clear water outlet of the sedimentation equipment is connected to a plate heat exchanger.

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