New plate heat exchanger for high-temperature exhaust waste heat recovery of heat setting machine

Abstract

The utility model discloses a novel plate heat exchanger for high-temperature waste gas waste heat recovery of heat setting machine, including heat exchanger body, its inside is equipped with several heat exchange passageway. Heat exchange passageway is asymmetric structure, and there is trapezoidal spoiler in, and bottom is equipped with V type flow guide groove. Asymmetric passageway optimization flow field distribution, trapezoidal spoiler enhances turbulence intensity, and both synergies promote heat transfer efficiency, makes nusselt number to promote 20%, and heat recovery efficiency reaches 85%;Large passageway width and V type flow guide groove synergistic reduce particulate matter deposition, and deposition amount reduces 62%, and the pressure drop increase amplitude is only 1 / 4 of traditional design, and the cleaning period is prolonged to 3 months.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, specifically to a novel plate heat exchanger for recovering waste heat from high-temperature exhaust gas in a heat setting machine. Background Technology

[0002] The dyeing and printing industry is a crucial component of my country's textile industry, accounting for over 40% of the industry's total energy consumption. Among these, the heat setting process, a critical step in dyeing and printing production, accounts for 30-40% of energy consumption. The exhaust gas from heat setting machines typically ranges in temperature from 180 to 220°C, containing a significant amount of recoverable waste heat. Heat balance tests show that only 29% of the heat energy consumed during fabric processing and setting is lost, with approximately 10% being lost to the machine itself. The remaining large amount of heat energy (about 60%) is emitted into the atmosphere along with the high-temperature flue gas. However, due to technological limitations, the waste heat recovery rate from heat setting machines in domestic dyeing and printing enterprises is generally below 35%.

[0003] Industrial heat exchangers mainly include three types: tubular, plate, and heat pipe. Tubular heat exchangers have a simple structure but are prone to dust accumulation, difficult to clean, and experience significant efficiency degradation over long-term operation. Plate heat exchangers, while having high heat transfer efficiency, are extremely sensitive to grease and particulate matter in exhaust gases due to their narrow channel design, leading to significant clogging problems and an annual efficiency decline rate exceeding 15%, requiring frequent shutdowns for cleaning (cycle ≤1 month). Heat pipe heat exchangers offer excellent heat transfer performance, but have high manufacturing costs and are sensitive to pollutants, hindering large-scale adoption. The core of these problems lies in the deposition of grease and particulate matter from exhaust gases on the heat exchanger surface, causing existing heat exchangers to experience a general decrease in heat transfer efficiency of over 30% after 3-6 months of operation.

[0004] Therefore, developing a plate heat exchanger for high-temperature waste heat recovery from heat setting machines with high heat transfer efficiency, good anti-clogging performance, and low maintenance cost is of great practical significance. Utility Model Content

[0005] The purpose of this utility model is to overcome the above-mentioned problems in the prior art and provide a new type of plate heat exchanger for high-temperature exhaust gas waste heat recovery in heat setting machines. This heat exchanger has the advantages of high heat transfer efficiency, good anti-clogging performance, and low maintenance cost.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A novel plate heat exchanger for high-temperature exhaust heat recovery from heat setting machines includes a heat exchanger body. The heat exchanger body has several heat exchange channels inside, each with an asymmetrical channel structure. The upper width of the asymmetrical channel structure is 3-9 mm, and the lower width is 9-16 mm. Trapezoidal baffles are provided within each heat exchange channel, with a height of 1-6 mm, a spacing of 20-70 mm, and an inclination angle of 10-50°. A V-shaped guide groove is provided at the bottom of each heat exchange channel, with a depth of 1-5 mm and an opening angle of 40-80°. Further optimized, the upper width of the asymmetric channel structure is 6mm, and the lower width (length) is 12mm. The gradient flow field formed by the width difference between the upper and lower ends reduces the flow field cooperation angle from 45° in the traditional symmetric channel to 28°, improving the cooperation between the velocity field and the temperature gradient field by 38%. Simultaneously, gravity reduces grease deposition at the bottom of the channel, decreasing the low-velocity area ratio from 25% to 10%. The heat exchange channel is equipped with trapezoidal baffles, each 3mm high, spaced 50mm apart, and tilted at 30°. At a flow velocity of 2.5m / s, the Nusselt number (Nu) increases from 71.3 in the traditional structure to 85.6, achieving a 20% heat transfer enhancement effect. Simultaneously, it induces longitudinal vortex flow, enhancing boundary layer disturbance and increasing heat recovery efficiency to 85%. The bottom of the heat exchange channel is equipped with a V-shaped guide groove with a depth of 2mm and an opening angle of 60°. Simulation by discrete phase model shows that the wall deposition rate of 1-10μm particles can be reduced by 62%. After 90 days of operation, the amount of fouling deposited is only 5.0g / m², which is much lower than 18.0g / m² of the traditional structure. At the same time, it guides the directional flow of condensate film and reduces the thermal resistance of liquid film.

[0007] Further preferably, the trapezoidal turbulence-inducing vanes are periodically arranged within the heat exchange channel. This periodic arrangement at a fixed interval of 50mm creates a stable turbulence disturbance frequency (1.2Hz), preventing sudden pressure drop caused by localized flow field disturbances and keeping the heat transfer coefficient fluctuation within ±3%.

[0008] Furthermore, the V-shaped guide channel is set along the length of the heat exchange channel; this enables continuous descaling throughout the entire process, shortens the migration distance of particles to 1 / 3 of the channel width, avoids local accumulation that forms a "bridging" blockage, and reduces the risk of channel blockage by 75%.

[0009] Furthermore, the heat exchanger body is made of metallic material. The thermal conductivity of metallic material is ≥45W / (m・K), which improves the heat transfer efficiency by more than 50% compared with non-metallic materials, while meeting the long-term service requirements of high-temperature exhaust gas at 220℃, and the thermal deformation of the material is controlled within 0.15mm / m.

[0010] Furthermore, the metal material is stainless steel. 304 stainless steel has a flue gas corrosion resistance rate of ≤0.02mm / year, a hardness of HV200, and a 40% improvement in wear resistance, solving the problem of rust and perforation of traditional carbon steel materials within 3 months, and extending its service life to more than 5 years.

[0011] Furthermore, the heat exchanger body is equipped with an exhaust gas inlet and an exhaust gas outlet at both ends. A flange-type sealing connection is used, with a leakage rate ≤0.01m³ / h, ensuring a completely closed flow of high-temperature exhaust gas (180-220℃) and controlling heat loss to within 5%.

[0012] Furthermore, a speed control device is installed at the exhaust gas inlet to control the speed of the exhaust gas entering the heat exchange channel. This allows for stepless adjustment of the exhaust gas speed within the range of 1.0-4.0 m / s, matching different operating conditions of the heat setting machine (such as fabric type and machine speed changes), and ensuring that the heat recovery efficiency remains stable at over 80%.

[0013] Furthermore, the speed control device is a variable frequency fan. The variable frequency adjustment response time is ≤2s, and the energy saving rate reaches 30%. Compared with the traditional valve throttling method, it saves 12,000 kWh of electricity per year, while avoiding local eddy current wear caused by throttling.

[0014] Furthermore, the heat exchanger body is equipped with a pressure detection device to detect the pressure drop within the heat exchange channel. Real-time monitoring of channel pressure drop changes, with an accuracy of ±0.5%FS, can provide early warning of blockage risks up to 15 days in advance, preventing sudden shutdowns.

[0015] Furthermore, the pressure detection device is a differential pressure transmitter. It adopts a diaphragm sensor, which can withstand temperatures up to 250℃, has a measurement range of 0-500Pa, and a long-term stability error of ≤0.2% / year, thus solving the drift problem of traditional pressure gauges that are easily affected by high-temperature steam.

[0016] This utility model has the following beneficial effects: Significantly improved heat transfer performance: Through the optimized design of asymmetric channels and trapezoidal baffles, the Nusselt number is increased by 20%, and the heat recovery efficiency reaches 85%, close to the theoretical limit (90%), which can more fully recover the waste heat in the high-temperature exhaust gas of the heat setter.

[0017] Excellent anti-clogging performance: The large channel and V-shaped guide groove design effectively reduce particulate matter deposition, reducing the deposition amount by 62%, and the pressure drop increase is only 1 / 4 of that of the traditional design. The cleaning cycle is extended from 1 month to 3 months, reducing the number of downtime cleanings and increasing the continuous operation time of the equipment.

[0018] Reduced maintenance costs: Maintenance cycles are extended, maintenance frequency is reduced by 67%, and annual maintenance costs are estimated to be reduced by 62.5%, while also reducing production interruption losses caused by maintenance.

[0019] Significant economic and environmental benefits: In a pilot application at a printing and dyeing factory in Zhejiang, the system's steam consumption was significantly reduced by 18%, equivalent to an annual saving of 360,000 yuan in operating costs, and CO2 emissions were reduced by 200 tons per year, in line with the national dual-carbon strategy requirements.

[0020] High adaptability: Under low flow rate conditions (1.0 m / s), the new structure can still maintain a high CPC value (1.28), demonstrating excellent low load adaptability and is suitable for the variable operating conditions commonly encountered in industrial applications. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the heat exchanger of this utility model; Figure 2 This is a schematic diagram of the cross-section of the heat exchange channel of this utility model; Figure 3 This is a schematic diagram of the trapezoidal spoiler arrangement of this utility model; In the diagram: 1-Heat exchanger body, 2-Heat exchange channel, 3-Trapezoidal baffle, 4-V-shaped guide channel, 5-Exhaust gas inlet, 6-Exhaust gas outlet, 7-Variable frequency fan, 8-Differential pressure transmitter. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and relevant knowledge. Obviously, the described applications are only some embodiments of the present invention, and not all embodiments.

[0023] The present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Reference Figures 1-3 As shown, a novel plate heat exchanger for high-temperature exhaust heat recovery from a heat setting machine includes a heat exchanger body 1, which is made of stainless steel and has several heat exchange channels 2 inside.

[0025] Heat exchange channel 2 has an asymmetric channel structure with a width of 6 mm at the top and a width (length) of 12 mm at the bottom, which can effectively optimize the flow field distribution.

[0026] Trapezoidal baffles 3 are periodically arranged within the heat exchange channel. The height of each baffle 3 is 3 mm, the spacing is 50 mm, and the inclination angle is 30°. These parameters are determined through parametric scanning optimization, which enhances turbulence intensity and improves heat transfer efficiency. A V-shaped guide channel 4 is provided along the length of the bottom of the heat exchange channel. The depth of the V-shaped guide channel 4 is 2 mm, and the opening angle is 60°. This guide channel guides particulate matter to migrate towards the mainstream area, reducing deposition on the wall surface.

[0027] The heat exchanger body has an exhaust gas inlet and an exhaust gas outlet at both ends. A variable frequency fan 7 is installed at the exhaust gas inlet 5 as a speed control device to control the velocity of the exhaust gas entering the heat exchange channel, making it adjustable within the range of 1.0-4.0 m / s. A differential pressure transmitter 8 is installed on the heat exchanger body as a pressure detection device to detect the pressure drop within the heat exchange channel, with a range of 0-500 Pa and an accuracy of ±0.5%.

[0028] In actual operation, the high-temperature exhaust gas from the heat setting machine enters the heat exchange channel through exhaust gas inlet 5. Through the synergistic effect of the asymmetrical channel, trapezoidal baffles, V-shaped guide channels, and a large channel width (consistent with the upper width), efficient heat transfer and reduced blockage are achieved. The heat-exchanged exhaust gas is then discharged through exhaust gas outlet 6. The exhaust gas speed is adjusted by a variable frequency fan, and pressure drop changes are monitored by a differential pressure transmitter 8. Cleaning and maintenance are performed when the pressure drop reaches a set threshold or when the operating time reaches 90 days.

[0029] The novel plate heat exchanger of this invention exhibits significant advantages in heat transfer enhancement, anti-clogging performance, and long-term operational reliability, providing a more competitive solution for waste heat recovery in the dyeing and printing industry and possessing broad prospects for widespread application.

[0030] The asymmetric channel structure (6mm at the top, 12mm at the bottom) optimizes the flow field distribution, reduces the area of ​​the low-velocity zone, and utilizes gravity to assist in scale removal. The asymmetric channel structure reduces the flow field cooperation angle from 45° to 28°, significantly improving the synergy between the velocity field and the temperature gradient field, thereby enhancing heat transfer efficiency. Simultaneously, the proportion of the low-velocity zone is reduced from 25% to 10%, minimizing the adverse effects of dead zones on heat transfer. Furthermore, gravity helps reduce the deposition of grease and particulate matter at the bottom of the channel.

[0031] Trapezoidal baffles (3mm height, 50mm spacing, 30° inclination) induce periodic disturbances in the fluid boundary layer, enhancing turbulence intensity and improving heat transfer. Experimental results show that, under a flow velocity of 2.5m / s, the Nusselt number (Nu) of the novel plate heat exchanger equipped with these trapezoidal baffles is significantly increased from 71.3 in the traditional type to 85.6, a relative increase of 20%, and the heat recovery efficiency is improved to 85%, approaching the theoretical limit of 90%.

[0032] The V-shaped guide channel (2mm depth, 60° opening angle) guides particulate matter to migrate towards the mainstream area, reducing the tendency for wall deposition. Experimental data show that after 30, 60, and 90 days of operation, the fouling deposition of the new plate heat exchanger was 3.5 g / m², 4.2 g / m², and 5.0 g / m², respectively, which is far lower than the 8.2 g / m², 12.5 g / m², and 18.0 g / m² of the traditional plate heat exchanger, significantly reducing particulate matter deposition.

[0033] The specific implementation process is as follows: A V-shaped guide channel is designed at the bottom of the heat exchange channel, with a depth of 2mm and an opening angle of 60°. The trajectory of particulate matter is simulated using a discrete phase model to verify the guiding effect of the structure on the migration of particulate matter. The size parameters are determined after multiple experiments and adjustments.

[0034] In this invention, the asymmetric channel structure and the trapezoidal baffle work together: the asymmetric channel optimizes the overall flow field distribution, reduces the low-speed zone, and provides a favorable flow field environment for the trapezoidal baffle to play a better role; the trapezoidal baffle further enhances the turbulence intensity in this flow field environment, and the combined effect of the two significantly improves the heat transfer efficiency and greatly reduces the flow field cooperation angle.

[0035] The synergistic effect of the wide channel width and the V-shaped guide channel: The wide channel width provides ample space for the V-shaped guide channel to guide the migration of particles, reducing the congestion of particles in the channel; the V-shaped guide channel effectively guides particles to move towards the mainstream area, avoiding deposition on the channel wall. The combination of the two significantly reduces the amount of deposition and improves the anti-clogging performance. At the same time, the wide channel width inhibits the secondary suspension of particles, complementing the guiding effect of the V-shaped guide channel.

[0036] In this invention, the asymmetric channel, trapezoidal baffles, V-shaped guide grooves, and large channel width together form an organic whole, improving heat transfer efficiency while minimizing clogging. The asymmetric channel and trapezoidal baffles are mainly responsible for enhancing heat transfer, while the large channel width and V-shaped guide grooves are mainly responsible for preventing clogging. Their cooperation greatly improves the overall performance of the new plate heat exchanger, with the coefficient of performance (CPC) remaining stably between 1.28 and 1.34 in the flow velocity range of 1.0-4.0 m / s, far exceeding that of traditional plate heat exchangers.

[0037] This invention, through the synergistic design of an asymmetric channel (6mm at the top, 12mm at the bottom) and trapezoidal baffles (3mm in height, 50mm spacing, 30° inclination), increases the Nusselt number (Nu) from 71.3 in the traditional structure to 85.6 at a flow velocity of 2.5m / s, a relative increase of 20%; the heat recovery efficiency is improved to 85%, approaching the theoretical limit of 90%. The flow field coordination angle is reduced from 45° in the traditional structure to 28°, significantly improving the coordination between the velocity field and the temperature gradient field; simultaneously, the asymmetric channel reduces the area ratio of the low-velocity region (velocity <0.5m / s) (from 25% to 10%), reducing the adverse effects of flow dead zones on heat transfer and minimizing thermodynamic irreversibility. The combined design of the large channel and V-shaped guide trough (2mm depth, 60° opening angle) guides particulate matter migration towards the mainstream area and inhibits secondary suspension of particulate matter. This results in fouling deposits of only 3.5g / m², 4.2g / m², and 5.0g / m² after 30, 60, and 90 days of operation, respectively, significantly lower than the traditional structure's 8.2g / m², 12.5g / m², and 18.0g / m², representing a 62% reduction in deposit volume. After 100 hours of continuous operation, the pressure drop of the new structure increased from an initial 130Pa to 140Pa, an increase of only 7.7%, while the pressure drop of the traditional structure increased from 120Pa to 156Pa, an increase of 30%. Based on a deposit volume threshold of 5.0g / m², the maintenance cycle was extended from the traditional 30 days to 90 days, reducing maintenance frequency by 67% and annual maintenance costs by 62.5%.

[0038] Reference Figure 2 and Figure 3 The installation process of the trapezoidal spoiler is shown below; Installation process: Channel pre-processing → spoiler embedding → integrated fixing. Figure 2 Trapezoidal slots are milled into the left and right sidewalls of the heat exchange channel along the length of the channel. The cross-sectional shape of the slot matches the right trapezoid of the trapezoidal baffle. The depth of the slot is equal to the height of the baffle (3mm), ensuring that the top of the baffle is flush with the inner wall of the channel (or slightly protrudes to form turbulence) after it is embedded. The spacing of the slots is 50mm, and they are evenly distributed along the length of the channel.

[0039] The spoiler is embedded, and Figure 3 The trapezoidal spoilers 3 are inserted one by one. Figure 2 The trapezoidal slot of the channel: the right-angled side of the spoiler (the side with a height of 3mm) engages with the slot on the side wall of the channel to achieve initial positioning; the inclined side of the spoiler (at a 30° angle with the bottom surface of the channel) faces the inside of the channel to guide the airflow to form a vortex.

[0040] Integrated fixing, using laser welding, welding the contact edge of the baffle to the side wall of the channel: the welding width ≤ 0.5mm, to avoid excessive welding that may cause channel deformation; the welding strength must meet the following: under 220℃ high temperature and 2.5m / s airflow impact, the connection force between the baffle and the channel > 500N.

[0041] Structural adaptation: Upper end (6mm wide): High airflow velocity, with a 3mm high spoiler that occupies 50% (3 / 6) of the channel width, which can violently disturb high-speed airflow; Lower end (12mm wide): Low airflow velocity, with a 3mm high spoiler that occupies 25% (3 / 12) of the channel width, which avoids excessive blockage of the low-speed zone.

[0042] The coordination between height and flow field: the 3mm high baffle forms a semi-blockage at the upper end of the channel (6mm wide), forcing the high-speed airflow to split and form vortices; at the lower end of the channel (12mm wide), it forms local disturbances, activating the airflow in the low-speed zone (avoiding flow dead zones), and reducing the flow field coordination angle in the channel from 45° to 28°.

[0043] A 3mm high baffle creates a periodic obstruction within the channel: when high-temperature exhaust gas (220℃) flows through at a velocity of 2.5m / s, the baffle cuts the airflow, forming a longitudinal vortex (vortex diameter ≈ 3mm, matching the baffle height); the vortex scours the channel wall, disrupting the thermal boundary layer (thickness reduced from 0.8mm to 0.5mm), increasing the Nusselt number (Nu) from 71.3 to 85.6 (an increase of 20%).

[0044] Collaborative V-shaped guide channel for scale removal, with baffle plate height of 3mm, and Figure 2 The V-shaped guide channel (2mm depth, 60° opening angle) creates a turbulence-guide linkage: the turbulence plate throws particles (1-10μm) in the airflow to the bottom of the channel and falls into the V-shaped guide channel; the 3mm high turbulence plate does not block the opening of the guide channel (60° angle is large enough), ensuring that the particles slide smoothly into the channel, reducing the deposition rate from 18.0g / m² to 5.0g / m² (a reduction of 62%).

[0045] Example 1: A novel plate heat exchanger for high-temperature exhaust heat recovery from a heat setting machine includes a heat exchanger body. The heat exchanger body has several heat exchange channels inside, each with an asymmetrical channel structure. The upper end of the asymmetrical channel structure has a width of 6mm, and the lower end has a width of 12mm. Trapezoidal baffles are provided within each heat exchange channel. The height of the trapezoidal baffles is 3mm, the spacing is 50mm, and the inclination angle is 30°. A V-shaped guide groove is provided at the bottom of each heat exchange channel. The depth of the V-shaped guide groove is 2mm, and the opening angle is 60°.

[0046] Example 2 discloses a novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine. The heat exchanger body is made of 304 stainless steel and has several independent heat exchange channels arranged in parallel inside, forming a modular assembly structure. The exhaust gas inlet and outlet are sealed at both ends of the heat exchanger body via flanges, with a leakage rate controlled below 0.01 m³ / h, ensuring a completely closed-loop flow of the 180-220℃ high-temperature exhaust gas with a heat loss ≤5%.

[0047] Asymmetric channel structure: The heat exchange channel adopts an asymmetric variable cross-section design, narrower at the top and wider at the bottom, with the upper width precisely controlled at 6mm and the lower width at 12mm. This structure reduces the flow field coordination angle from 45° in traditional symmetric channels to 28°, improving the coordination between the velocity field and the temperature gradient field by 38%. At the same time, with the help of a gravity-assisted descaling mechanism, the area ratio of the low-velocity zone (velocity <0.5m / s) is reduced from 25% to 10%, minimizing the adverse effects of flow dead zones on heat transfer.

[0048] Trapezoidal baffle arrangement: Trapezoidal baffles are periodically fixed on the inner wall of the heat exchange channel. Through parametric scanning optimization (multiple sets of comparative experiments with heights of 1-5mm, spacing of 30-70mm, and inclination angles of 15°-45°), the optimal parameters were determined to be: height 3mm, spacing between adjacent baffles 50mm, and inclination angle of 30° to the bottom of the channel. Under a flow velocity of 2.5m / s, this structure can induce periodic disturbances in the fluid boundary layer, enhance turbulence intensity, and increase the Nusselt number (Nu) from 71.3 in the traditional structure to 85.6, a relative increase of 20%, thereby improving the heat recovery efficiency to 85%.

[0049] V-shaped flow channel design: A V-shaped flow channel is opened along the length of the central axis at the bottom of the heat exchange channel, with a channel depth of 2mm and an opening angle of 60°. This structure can guide 10-100μm particles (density 1500kg / m³) to migrate towards the mainstream area, reducing the wall deposition rate by 62%; at the same time, it guides the directional flow of the condensate film, reducing the liquid film thermal resistance. The experiment used a 0.1μm pore size detachable filter membrane weighing method to determine the deposition rate: after 90 days of operation, the deposition rate of the new structure was only 5.0g / m², far lower than the 18.0g / m² of the traditional structure.

[0050] Auxiliary function components: A variable frequency fan is installed at the exhaust gas inlet as a speed control device to achieve stepless adjustment within the range of 1.0-4.0m / s, matching different working conditions of the heat setting machine.

[0051] The heat exchanger body is equipped with a differential pressure transmitter, which uses a diaphragm sensor that can withstand temperatures up to 250℃ and has a long-term stability error of ≤0.2% / year. It can monitor the pressure drop changes in the channel in real time and provide early warning of blockage risk up to 15 days in advance.

[0052] III. Experimental Verification System and Results A small-scale experimental setup was constructed for performance verification. The system components include: An electrically heated exhaust gas generator (temperature control accuracy ±2℃) simulates high-temperature exhaust gas (composition: N2 75%, CO2 15%, H2O 10%). A K-type thermocouple (accuracy ±0.5℃) and a differential pressure transmitter are used to collect temperature and pressure drop data. The test section is equipped with a 200℃-resistant transparent observation window, and the flow field is visualized using PIV technology. Data acquisition is performed using LabVIEW 2023 (sampling frequency 100Hz), and the data is filtered using the moving average method (window width 10s). The Nu number uncertainty is <5%, and the pressure drop uncertainty is <3%.

[0053] The key experimental results are shown in Table 1: Table 1

[0054] Engineering application effect In a pilot application at a printing and dyeing factory in Zhejiang, this new type of plate heat exchanger demonstrated significant benefits: Steam consumption decreased from 1.2t / h to 0.98t / h, a reduction of 18%; annual operating costs decreased from 2 million yuan to 1.64 million yuan, saving 360,000 yuan; annual CO2 emissions were reduced by 2,200 tons, with an energy efficiency of 18% (higher than the 15% of mainstream systems in the market); the cleaning cycle was extended to 90 days, and annual downtime was reduced by 60%, indirectly improving production efficiency by about 8%.

[0055] In this embodiment, the asymmetric channel and the trapezoidal baffle work together: the asymmetric channel optimizes the flow field distribution and provides a stable turbulent environment for the baffle; the baffle enhances the boundary layer disturbance, and together they reduce the flow field cooperation angle by 38% and increase the Nu number by 20%.

[0056] The large channel and V-shaped guide groove work together: the channel provides space for the guide groove to discharge scale, and the guide groove guides the migration of particles to avoid blockage. The combination of the two reduces the amount of deposits by 62%, and the pressure drop increase is only 1 / 4 of that of the traditional structure.

[0057] Although some embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, and all such changes and alterations should fall within the scope of the present invention.

Claims

1. A novel plate heat exchanger for recovering waste heat from high-temperature exhaust gas of a heat setting machine, characterized in that, The device includes a heat exchanger body, which has several heat exchange channels inside. The heat exchange channels have an asymmetrical channel structure with an upper width of 3-9 mm and a lower width of 9-16 mm. Trapezoidal baffles are provided inside the heat exchange channels. The height of the trapezoidal baffles is 1-6 mm, the spacing is 20-70 mm, and the inclination angle is 10-50°. A V-shaped guide groove is provided at the bottom of the heat exchange channels. The depth of the V-shaped guide groove is 1-5 mm, and the opening angle is 40-80°.

2. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 1, characterized in that, The trapezoidal baffles are periodically arranged within the heat exchange channel.

3. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 1, characterized in that, The V-shaped guide groove is arranged along the length of the heat exchange channel.

4. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 1, characterized in that, The heat exchanger body is made of metal.

5. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 4, characterized in that, The metal material is stainless steel.

6. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 1, characterized in that, The heat exchanger body has an exhaust gas inlet and an exhaust gas outlet at both ends.

7. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 6, characterized in that, A speed control device is provided at the exhaust gas inlet to control the speed of the exhaust gas entering the heat exchange channel.

8. The novel plate heat exchanger for high-temperature exhaust heat recovery from a heat setting machine according to claim 7, characterized in that, The speed control device is a variable frequency fan.

9. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 1, characterized in that, The heat exchanger body is equipped with a pressure detection device for detecting the pressure drop in the heat exchange channel.

10. The novel plate heat exchanger for high-temperature exhaust gas waste heat recovery from a heat setting machine according to claim 9, characterized in that, The pressure detection device is a differential pressure transmitter.

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