An oven exhaust waste heat recovery system

Abstract

The utility model provides a kind of oven waste gas waste heat recovery system, it solves the problem such as oven waste heat recovery, it includes the oven connected with induced draft fan, oven is equipped with exhaust fan, exhaust fan is connected with gas-gas heat exchanger by filter, gas-gas heat exchanger is connected with gas-water heat exchanger, and the cold side outlet of gas-gas heat exchanger is communicated with induced draft fan.The utility model has the advantages of high waste heat recovery rate, stable operation etc..

Description

Technical Field

[0001] This utility model belongs to the field of waste gas heat recovery technology, specifically relating to a waste heat recovery system for oven exhaust gas. Background Technology

[0002] In industries such as printing, coating, and textiles, drying ovens generate large amounts of high-temperature waste gas when used to dry materials. This waste gas contains significant amounts of organic solvents and heat; direct emission not only wastes energy but also pollutes the environment. Currently, common treatment methods include direct emission or simple adsorption treatment, but these methods suffer from energy waste and incomplete treatment.

[0003] To address the shortcomings of existing technologies, people have conducted long-term explorations and proposed various solutions. For example, Chinese patent literature discloses a waste heat recovery device for a coating machine oven [201920001185.6], which includes an oven exhaust duct, an exhaust fan, a heat exchanger duct, a heat exchanger, a waste heat outlet duct, an outlet horizontal pipe, a return air duct duct, and a return air duct. The exhaust fan is connected to the exhaust duct, and the high-temperature waste gas passes through the heat exchanger duct, absorbing heat from the waste gas to raise the temperature of the fresh air absorbed from the outside. The fresh air then enters the return air duct through the waste heat outlet duct, the outlet horizontal pipe, and the return air duct duct. The return air duct is connected to the coating machine oven, forming a waste heat recovery pipeline. In this invention, the high-temperature waste gas is blown into the heat exchanger by the exhaust fan, and the heat exchanger absorbs heat from the fresh air absorbed from the outside to raise its temperature before entering the return air duct. The above solution has solved the problem of waste heat recovery to some extent, but it still has many shortcomings, such as insufficient heat recovery and utilization rate and poor pollutant treatment effect. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a reasonably designed waste heat recovery system for oven exhaust gas with a high heat recovery and utilization rate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a waste heat recovery system for oven exhaust gas, comprising an oven connected to an induced draft fan, the oven being equipped with an exhaust fan, the exhaust fan being connected to a gas-to-gas heat exchanger via a filter, the gas-to-gas heat exchanger being connected to a gas-to-water heat exchanger, and the cold side outlet of the gas-to-gas heat exchanger being connected to the induced draft fan.

[0006] In the aforementioned oven exhaust heat recovery system, the filter includes an air inlet pipe with a spindle-shaped filter section. Inside the filter section, several filter screens arranged axially are installed. The filter screens are hemispherical, and a reversing component is provided between the filter screens and the filter section.

[0007] In the aforementioned oven exhaust heat recovery system, the reversing assembly includes reversing rods disposed on both sides of the filter screen. The reversing rods are rotatably connected to the filter section, and the reversing rods are drively connected to a reversing linkage rotatably mounted on the outside of the filter section. A reversing valve and a cleaning pipe connected to the reversing valve are connected to the outlet of the air inlet pipe.

[0008] In the aforementioned oven exhaust heat recovery system, the oven is equipped with several vertically arranged support frames, with placement cavities between adjacent support frames. The induced draft fan is connected to the lower end of the oven, and the exhaust fan is connected to the upper end of the oven.

[0009] In the aforementioned oven exhaust heat recovery system, the oven has an insulation layer, and a temperature sensor and a humidity sensor are installed inside the oven.

[0010] In the aforementioned oven exhaust heat recovery system, the gas-to-gas heat exchanger includes a heat exchange shell, a heat exchange plate installed inside the heat exchange shell, an exhaust gas channel built into the heat exchange plate, adjacent heat exchange plates are kept isolated and an air channel is left between them, an air channel is left between the heat exchange plate and the heat exchange shell, the heat exchange plate has heat exchange fins extending toward the air channel, and the air channel is connected to the induced draft fan through a return air duct.

[0011] In the aforementioned waste heat recovery system for oven exhaust gas, the gas-water heat exchanger includes a heat exchange tank. The heat exchange tank has built-in condenser tubes connected to an external water circuit. The condenser tubes are spirally coiled and have radially extending condenser fins. A liquid outlet is connected to the lower end of the heat exchange tank, and an inlet cylinder, an outlet pipe, and a pressure relief pipe are connected to the upper end of the heat exchange tank. The inlet cylinder extends to the bottom of the heat exchange tank to prevent short-circuiting with the outlet pipe.

[0012] In the aforementioned oven exhaust heat recovery system, the heat exchange tank is spherical, and the condenser tube is installed on the inner wall of the heat exchange tank.

[0013] In the aforementioned oven exhaust heat recovery system, the heat exchange tank has a built-in temperature sensor and a pressure sensor, and a level gauge is installed at the bottom of the heat exchange tank.

[0014] In the aforementioned oven exhaust heat recovery system, the gas-water heat exchanger is connected to the exhaust gas treatment system.

[0015] Compared with existing technologies, the advantages of this utility model are: the recovery system can realize the cascade recovery and utilization of waste heat from exhaust gas, and at the same time realize heat conduction through both gas and liquid media, thereby improving the heat recovery and utilization rate; the heat exchanger is equipped with a variety of sensing elements to realize multi-modal sensing of waste gas temperature, humidity and pressure, ensuring its recovery control and monitoring effect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the filter of this utility model; Figure 2This is a structural schematic diagram of the filter of this utility model from another perspective; Figure 3 This is a cross-sectional view of the filter structure of this utility model; Figure 4 This is a schematic diagram of the gas-to-gas heat exchanger of this utility model; Figure 5 This is a structural cross-sectional view of the gas-to-gas heat exchanger of this utility model; Figure 6 This is a cross-sectional view of the structure of the oven of this utility model; Figure 7 This is a schematic diagram of the structure of the gas-water heat exchanger of this utility model; Figure 8 This is a structural cross-sectional view of the gas-water heat exchanger of this utility model; Figure 9 This is a structural block diagram of the present invention; In the diagram, the components are: 1. Exhaust fan; 2. Filter; 21. Inlet pipe; 22. Filter section; 23. Filter screen; 24. Reversing rod; 25. Reversing connecting rod; 26. Reversing valve; 27. Cleaning pipe; 3. Oven; 31. Support frame; 32. Placement chamber; 4. Exhaust fan; 5. Gas-gas heat exchanger; 51. Heat exchange shell; 52. Heat exchange plate; 53. Air passage; 54. Exhaust gas passage; 55. Heat exchange fins; 56. Return air pipe; 6. Gas-water heat exchanger; 61. Heat exchange tank; 62. Condenser pipe; 63. Condenser fins; 64. Liquid outlet; 65. Inlet cylinder; 66. Pressure relief pipe; 67. Outlet pipe; and 7. Exhaust gas treatment system. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1-9 As shown, a waste heat recovery system for oven exhaust gas includes an oven 3 connected to an induced draft fan 1. The oven 3 is equipped with an exhaust fan 4, which is connected to a gas-to-gas heat exchanger 5 via a filter 2. The gas-to-gas heat exchanger 5 is connected to a gas-to-water heat exchanger 6, and the cold-side outlet of the gas-to-gas heat exchanger 5 is connected to the induced draft fan 1. This system maximizes the recovery of waste heat in the exhaust gas from the oven through two-stage heat exchange. The waste heat in the exhaust gas first passes through the gas-to-gas heat exchanger 5, recovering a portion of the heat and using it to preheat the fresh air entering the oven 3, significantly reducing the energy consumption of the oven 3. Then, the remaining heat passes through the gas-to-water heat exchanger 6, recovering the remaining heat and using it to heat industrial water or domestic hot water, maximizing the recovery of waste heat resources in the exhaust gas from the oven 3.

[0019] Specifically, the filter 2 includes an air inlet pipe 21, which has a spindle-shaped filter section 22. Several axially arranged filter screens 23 are installed inside the filter section 22. The filter screens 23 are hemispherical, increasing the effective filtration area and helping to guide airflow and reduce resistance. A reversing component is provided between the filter screens 23 and the filter section 22 to automatically change the airflow direction and initiate the cleaning process when the deposits on the filter screens 23 reach a certain level or when the system sets a cycle.

[0020] Specifically, the reversing assembly includes reversing rods 24 disposed on both sides of the filter screen 23. The reversing rods 24 are rotatably connected to the filter section 22, and are drively connected to a reversing connecting rod 25 rotatably mounted on the outside of the filter section 22. Through an external drive mechanism, such as a cylinder or motor, the reversing connecting rod 25 is driven to rotate, thereby causing the filter screen 23 or its support structure to deflect 180° to achieve reversal. A reversing valve 26 and a cleaning pipe 27 connected to the reversing valve 26 are connected to the outlet of the air inlet pipe 21. When the reversing assembly is activated, the reversing valve 26 switches synchronously, redirecting the airflow originally flowing to the oven 3 to the cleaning pipe 27. At the same time, the reverse airflow or pulse airflow generated by the pipeline steam or compressed air blows and cleans the filter screen 23, and the deposits are discharged from the system with the airflow through the cleaning pipe 27.

[0021] Furthermore, the oven 3 is equipped with several vertically arranged support frames 31 for placing the materials to be dried. The support frames 31 typically adopt a high-temperature resistant and breathable mesh structure. A placement cavity 32 is left between adjacent support frames 31. The induced draft fan 1 is connected to the lower end of the oven 3, and filtered and preheated fresh air enters from the bottom of the oven 3, which helps to form a uniform airflow from bottom to top, penetrating the material layer. The exhaust fan 4 is connected to the upper end of the oven 3, and the hot and humid exhaust gas is extracted from the top of the oven 3 for subsequent waste heat recovery.

[0022] Furthermore, oven 3 features a heat insulation layer composed of materials such as rock wool and aluminum silicate fiber, effectively reducing heat loss from the oven wall, improving thermal efficiency, and enhancing the working environment. Oven 3 is equipped with temperature and humidity sensors to monitor the internal operating conditions in real time, providing key parameters for temperature and humidity control, as well as optimizing the operation of the entire waste heat recovery system.

[0023] In addition, the air-to-air heat exchanger 5 includes a heat exchange shell 51, inside which heat exchange plates 52 are installed. Each heat exchange plate 52 has a built-in exhaust gas channel 54. Adjacent heat exchange plates 52 are isolated from each other, with an air channel 53 between them. High-temperature exhaust gas flows through the exhaust gas channel 54, releasing heat. An air channel 53 exists between the heat exchange plates 52 and the heat exchange shell 51. The heat exchange plates 52 have heat exchange fins 55 extending into the air channel 53, significantly increasing the contact area between the heat exchange plates 52 and the airflow within the air channel 53. Fresh air flows through the air channel 53, contacts the heat exchange fins 55, and absorbs the heat released by the exhaust gas in the exhaust gas channel 54, achieving preheating. The air channel 53 is connected to the induced draft fan 1 via a return air duct 56. The preheated fresh air is then sent into the oven 3 by the induced draft fan 1 through the return air duct 56.

[0024] Meanwhile, the gas-water heat exchanger 6 includes a heat exchange tank 61, with a built-in condenser tube 62 connected to an external water circuit. Cold water or water requiring heating flows through the condenser tube 62. The condenser tube 62 is spirally coiled and has radially extending condenser fins 63. The spiral coiling increases the tube length and turbulence effect, while the condenser fins 63 greatly expand the heat dissipation area outside the tube, jointly enhancing the heat exchange between gas and water. The lower end of the heat exchange tank 61 is connected to a liquid outlet 64, and the upper end of the heat exchange tank 61 is connected to an air inlet 65, an air outlet 67, and a pressure relief pipe 66. The cooled exhaust gas from the gas-gas heat exchanger 5 enters the heat exchange tank 61 through the air inlet 65, where it exchanges heat with the condenser tube 62, further cooling and releasing heat to heat the water inside the condenser tube 62. The pressure relief pipe 66 is used to maintain the system's safe pressure and can be connected to a safety valve or a vent pipe. The air inlet 65 extends to the bottom of the heat exchange tank to avoid short-circuiting with the air outlet 67.

[0025] As can be seen, the heat exchange tank 61 is spherical, which has good pressure resistance and high internal space utilization, which is conducive to the uniformity of airflow and water flow distribution. The condenser tube 62 is installed on the inner wall of the heat exchange tank 61, making full use of the internal space of the tank.

[0026] Clearly, the heat exchange tank 61 incorporates temperature and pressure sensors to monitor the exhaust gas temperature, water temperature, and internal pressure, ensuring a safe and controllable heat exchange process and providing feedback signals for the system's automatic control. A level gauge at the bottom of the heat exchange tank 61 monitors the amount of condensate buildup. When the level reaches a set height, the outlet 64 can be opened automatically or manually to drain the condensate, preventing excessive buildup from affecting heat exchange or causing corrosion.

[0027] Preferably, the gas-water heat exchanger 6 is connected to the exhaust gas treatment system 7. If the low-temperature exhaust gas after two-stage waste heat recovery still contains a small amount of volatile organic compounds, it can be further introduced into the exhaust gas treatment system 7 for exhaust gas treatment to achieve harmless emission.

[0028] In summary, the principle of this embodiment is as follows: the filter 2 efficiently purifies the intake air and uses the reversing component to achieve automatic back-blowing and dust removal of the filter screen 23; the hot and humid exhaust gas is drawn out from the top of the oven 3 by the exhaust fan 4; this heat is transferred to the fresh air introduced by the induced draft fan 1 through the heat exchange fins 55 extending to the air channel 53, realizing the preheating of the fresh air by the waste heat of the exhaust gas; then the cooled exhaust gas enters the gas-water heat exchanger 6, and performs deep heat exchange with the spirally coiled condenser tube 62 with condenser fins 63 in the heat exchange tank 61, further releasing heat to heat the tube water circuit, and finally realizing the cascade recovery of exhaust gas energy. The purification and filtration, the full-process monitoring of temperature / humidity / pressure / liquid level and the exhaust gas treatment system 7 together ensure the efficient, safe and environmentally friendly operation of the system.

[0029] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

[0030] Although this document frequently uses terms such as induced draft fan 1, filter 2, air inlet pipe 21, filter section 22, filter screen 23, reversing rod 24, reversing connecting rod 25, reversing valve 26, cleaning pipe 27, oven 3, support frame 31, placement chamber 32, exhaust fan 4, gas-to-gas heat exchanger 5, heat exchange shell 51, heat exchange plate 52, air passage 53, exhaust gas passage 54, heat exchange fins 55, return air pipe 56, gas-water heat exchanger 6, heat exchange tank 61, condenser tube 62, condenser fins 63, liquid outlet 64, air inlet cylinder 65, pressure relief pipe 66, exhaust pipe 67, and exhaust gas treatment system 7, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.

Claims

1. A waste heat recovery system for oven exhaust gas, comprising an oven (3) connected to an induced draft fan (1), wherein the oven (3) is equipped with an exhaust fan (4), characterized in that, The exhaust fan (4) is connected to a gas-to-gas heat exchanger (5) through a filter (2). The gas-to-gas heat exchanger (5) is connected to a gas-to-water heat exchanger (6). The cold side outlet of the gas-to-gas heat exchanger (5) is connected to the induced draft fan (1).

2. The waste heat recovery system for oven exhaust gas according to claim 1, characterized in that, The filter (2) includes an air inlet pipe (21), which has a spindle-shaped filter section (22). The filter section (22) is equipped with a plurality of filter screens (23) arranged along the axial direction. The filter screens (23) are hemispherical. A reversing component is provided between the filter screens (23) and the filter section (22).

3. The waste heat recovery system for oven exhaust gas according to claim 2, characterized in that, The reversing assembly includes reversing rods (24) disposed on both sides of the filter screen (23). The reversing rods (24) are rotatably connected to the filter section (22). The reversing rods (24) are drively connected to the reversing connecting rods (25) rotatably installed on the outside of the filter section (22). The outlet of the air inlet pipe (21) is connected to a reversing valve (26) and a cleaning pipe (27) communicating with the reversing valve (26).

4. The waste heat recovery system for oven exhaust gas according to claim 1, characterized in that, The oven (3) is provided with several vertically arranged support frames (31), and a placement cavity (32) is left between adjacent support frames (31). The induced draft fan (1) is connected to the lower end of the oven (3), and the exhaust fan (4) is connected to the upper end of the oven (3).

5. The waste heat recovery system for oven exhaust gas according to claim 4, characterized in that, The oven (3) has a heat insulation layer, and a temperature sensor and a humidity sensor are installed inside the oven (3).

6. The waste heat recovery system for oven exhaust gas according to claim 1, characterized in that, The gas-to-gas heat exchanger (5) includes a heat exchange shell (51), a heat exchange plate (52) is installed inside the heat exchange shell (51), the heat exchange plate (52) has a built-in exhaust gas channel (54), adjacent heat exchange plates (52) are kept isolated and an air channel (53) is left between them, an air channel (53) is left between the heat exchange plate (52) and the heat exchange shell (51), the heat exchange plate (52) has heat exchange fins (55) extending toward the air channel (53), and the air channel (53) is connected to the induced draft fan (1) through a return air pipe (56).

7. The waste heat recovery system for oven exhaust gas according to claim 6, characterized in that, The gas-water heat exchanger (6) includes a heat exchange tank (61), which has a built-in condenser tube (62) and is connected to an external water circuit. The condenser tube (62) is spirally coiled and has radially extending condenser fins (63). The lower end of the heat exchange tank (61) is connected to a liquid outlet (64), and the upper end of the heat exchange tank (61) is connected to an air inlet (65), an air outlet (67), and a pressure relief pipe (66).

8. The waste heat recovery system for oven exhaust gas according to claim 7, characterized in that, The heat exchange tank (61) is spherical, and the condenser tube (62) is installed on the inner wall of the heat exchange tank (61).

9. A waste heat recovery system for oven exhaust gas according to claim 7, characterized in that, The heat exchange tank (61) has a built-in temperature sensor and a pressure sensor, and a level gauge is provided at the bottom of the heat exchange tank (61).

10. A waste heat recovery system for oven exhaust gas according to claim 1, characterized in that, The gas-water heat exchanger (6) is connected to a tail gas treatment system (7).

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