Coating RTO hot air waste heat recovery system

Abstract

The utility model relates to a waste gas waste heat recovery system, in particular to a coating RTO hot air waste heat recovery system which comprises RTO equipment and an RTO hot air heat exchanger connected with the RTO equipment, and the RTO hot air heat exchanger is respectively connected with a hot air pressurizing fan A and a mixing fan through pipelines. The mixed fan is connected with the fresh air mechanism and the heating mechanism through pipelines, the heating mechanism is connected with the multiple drying ovens in parallel through pipelines, one part of the drying ovens are connected with the RTO equipment through pipelines, and the other part of the drying ovens are connected with the hot air pressurizing fan A in series through pipelines. High-concentration waste gas exhausted by the drying oven is combusted to supply heat, low-concentration waste gas is recycled, secondary recycling of heat energy is achieved, energy consumption is reduced, and cost is saved.

Description

Technical Field

[0001] The utility model relates to an exhaust gas waste heat recovery system, in particular to an RTO coating hot air waste heat recovery system. Background Art

[0002] Currently, printing inks and glues used in the printing and coating industries contain large amounts of organic solvents. After coating is completed, the coating is generally placed in an oven, and then hot air is delivered to the oven by a blower for drying. During the drying process, the organic solvent is heated in the oven, generating a large amount of organic waste gas. Currently, there are three methods for treating organic waste gas: the first is direct discharge, which not only wastes a large amount of organic solvent but also generates a large amount of pollution; the second method is simple adsorption and recovery using activated carbon before discharge; and the third method is to discharge the organic waste gas after burning it through RTO. In order to meet environmental emission requirements, the latter two methods are often used to treat organic waste gas. The activated carbon adsorption method has a significant effect once the adsorption is saturated, and RTO is limited to waste gas treatment. The oven drying process during the coating and compounding of the materials consumes a lot of energy and is costly. Utility Model Content

[0003] The utility model aims to solve the above-mentioned defects and provides a hot air waste heat recovery system for coating RTO.

[0004] In order to overcome the defects existing in the background technology, the technical solution adopted by the present invention to solve its technical problems is: a coating RTO hot air waste heat recovery system, including an RTO device, an RTO hot air heat exchanger connected to the RTO device, the RTO hot air heat exchanger is connected to the hot air pressure fan A and the mixing fan through pipelines, the mixing fan is connected to the fresh air mechanism and the heating mechanism through pipelines, the heating mechanism is connected in parallel with multiple ovens through pipelines, some of the ovens are connected to the RTO equipment through pipelines, and another part of the ovens are connected in series with the hot air pressure fan A through pipelines.

[0005] A further improvement includes providing an RTO hot air valve in series on the pipeline between the RTO hot air heat exchanger and the mixing fan.

[0006] A further improvement includes providing a fresh air valve A in series on the pipeline between the fresh air mechanism and the mixing fan.

[0007] A further improvement includes providing a hot air pressurizing blower B in series on the pipeline between the RTO hot air heat exchanger and the RTO hot air valve.

[0008] A further improvement includes providing a temperature detection unit on the pipeline between the mixing fan and the heating mechanism.

[0009] A further improvement includes connecting the fresh air mechanism to the pipeline between the mixing fan and the heating mechanism through a secondary pipe, and a fresh air valve B is provided in series on the secondary pipe.

[0010] A further improvement includes providing an exhaust fan and an exhaust valve in series on the pipeline connecting the oven and the hot air pressure fan A.

[0011] A further improvement includes that the heating mechanism includes a steam heater and an auxiliary electric heater.

[0012] The beneficial effects of the utility model are as follows: the design realizes secondary recovery of heat energy by burning high-concentration exhaust gas discharged from the oven for heat supply and recycling low-concentration exhaust gas, thereby reducing energy consumption and saving costs; the auxiliary electric heater and steam heater are used for auxiliary heating when the production line is just started. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] Figure 1 It is the main view of the utility model;

[0015] In the figure, 1-hot air pressurizing fan A, 2-RTO equipment, 3-RTO hot air heat exchanger, 4-hot air pressurizing fan B, 5-RTO hot air valve, 6-fresh air valve A, 7-mixing fan, 8-fresh air valve B, 9-steam heater, 10-auxiliary electric heater, 11-temperature detection unit, 12-oven, 13-exhaust fan, 14-exhaust valve, 15-secondary pipe. DETAILED DESCRIPTION

[0016] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. The embodiments of the basic utility model and all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present utility model.

[0017] like Figure 1As shown, a coating RTO hot air waste heat recovery system includes an RTO device 2 and an RTO hot air heat exchanger 3 connected to the RTO device 2. The RTO hot air heat exchanger 3 is connected to the hot air pressure fan A1 and the mixing fan 7 through pipelines respectively. The mixing fan 7 is connected to the fresh air mechanism and the heating mechanism through pipelines respectively. The heating mechanism is connected in parallel with multiple ovens 12 through pipelines. A part of the ovens 12 is connected to the RTO device 2 through pipelines, and is used to discharge the exhaust air containing self-igniting solvent generated during the initial drying and coating into the combustion chamber in the RTO device 2 for combustion. The other part of the ovens 12 is connected in series with the hot air pressure fan A1 through pipelines, and then the exhaust air with temperature discharged after drying is recycled and reused, and the waste heat is reused to achieve secondary recovery of thermal energy, protect the environment and save costs.

[0018] An RTO hot air valve 5 is provided in series on the pipeline between the RTO hot air heat exchanger 3 and the mixing fan 7 , and the RTO hot air valve 5 is used to control the on-off of the pipeline.

[0019] A fresh air valve A6 is arranged in series on the pipeline between the fresh air mechanism and the mixing fan 7. The fresh air valve A6 is used to control whether the fresh air enters the mixing fan 7. The mixing fan 7 mixes the hot air with the fresh air, thereby cooling the hot air from 250°C to 180°C. The opening and closing of the fresh air valve A6 is adjusted to adjust the amount of fresh air entering, and then adjust the temperature.

[0020] A hot air pressure fan B4 is arranged in series on the pipeline between the RTO hot air heat exchanger 3 and the RTO hot air valve 5. The hot air pressure fan B4 is used to ensure that the hot air is smoothly input into the oven 12. In a further implementation method, the RTO hot air heat exchanger 3 can be arranged in parallel with multiple hot air pressure fans B4 to realize the synchronous operation of multiple oven 12 production lines and achieve batch drying of the coating.

[0021] A temperature detection unit 11 is provided on the pipeline between the mixing fan 7 and the heating mechanism. After the mixing fan 7 mixes the hot air with the fresh air, the temperature detection unit 11 can be used to detect the temperature of the mixed air and adjust the input amount of the external fresh air to ensure that the temperature of the hot air input to the oven reaches 180°C and is not too high or too low.

[0022] The fresh air mechanism is connected to the pipeline between the mixing fan 7 and the heating mechanism through a secondary pipe 15. A fresh air valve B8 is arranged in series on the secondary pipe 15. When the temperature detection unit 11 detects that the mixed air temperature of the hot air and the fresh air is still higher than 180 degrees, the fresh air can be reintroduced by controlling the opening and closing of the fresh air valve B8 to perform secondary cooling on the mixed air.

[0023] An exhaust fan 13 and an exhaust valve 14 are arranged in series on the pipeline connecting the oven 12 and the hot air pressure fan A1. The exhaust fan 13 is used to accelerate the discharge of heated exhaust air and re-introduce the exhaust air into the RTO hot air heat exchanger through the hot air pressure fan A1. The exhaust valve 14 can be used to open and close the pipeline.

[0024] The heating mechanism includes a steam heater 9 and an auxiliary electric heater 10. When the RTO equipment 2 is just started, there is no input of solvent waste air. At this time, the RTO equipment 2 needs to use natural gas for heating to generate hot air. The temperature of the hot air input to the oven 12 at the time of just starting cannot reach the required temperature. Therefore, the steam heater 9 and the auxiliary electric heater 10 are needed to assist in heating the hot air.

[0025] Working principle: The hot air pressure fan A1 sends external air into the RTO hot air heat exchanger 3. At this time, since there is no self-igniting solvent evaporation in the oven 12, the combustion chamber in the RTO equipment 2 needs to use natural gas for combustion. The RTO hot air heat exchanger 3 is installed at the smoke outlet of the RTO equipment 2 for heat exchange. The heat exchange is performed on the air flowing through. The generated hot air is output through the hot air pressure fan B4. The hot air is input into the oven 12 through the pipeline through the RTO hot air valve 5, the mixing fan 7, the steam heater 9, and the auxiliary electric heater 10. When the RTO equipment 2 is just started, the exhaust starting temperature cannot reach 180 degrees Celsius. Therefore, the steam heater 9 and the auxiliary electric heater 10 are needed to heat the hot air to 180 degrees to dry the coating in the oven 12.

[0026] Part of the oven 12 is used for preliminary drying of the coating. The exhaust air containing high concentration of self-igniting solvent generated during the coating drying is directly discharged into the combustion chamber of the RTO equipment 2. At this time, the natural gas supply to the RTO equipment can be cut off, and the self-igniting solvent is used for combustion. Due to the continuous and stable combustion of the RTO equipment, 800-degree flue gas is generated, which is output as 250-degree hot air through heat exchange in the RTO hot air heat exchanger 3. The hot air is output through the RTO hot air valve 5. At the same time, the fresh air valve A6 is opened to introduce external room temperature air through the fresh air system. The hot air and fresh air are then mixed by the mixing fan 7 and discharged into the oven 12, thereby reducing the 250-degree hot air mixed with the fresh air to 180 degrees and input into the oven 12. At this time, the steam heater 9 and the auxiliary electric heater 10 stop working. When the temperature probe detects that the mixed air output by the mixing fan 7 is still above 180 degrees, the temperature probe controls the opening of the fresh air valve B8 to mix the mixed air output by the mixing fan 7 with the fresh air again to reduce the temperature, thereby reaching the temperature requirement of 180 degrees.

[0027] The other part of the oven 12 can be used for subsequent drying of the coating. The low-concentration exhaust gas with a temperature of about 70 degrees is discharged from the oven 12. The exhaust gas is output through the exhaust fan 13 and re-discharged into the RTO hot air heat exchanger 3 through the hot air pressure fan A1, thereby performing heat circulation and reducing energy consumption.

[0028] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A coating RTO hot air waste heat recovery system, characterized by: The invention comprises an RTO device (2) and an RTO hot air heat exchanger (3) connected to the RTO device (2), wherein the RTO hot air heat exchanger (3) is connected to the hot air pressure fan A (1) and the mixing fan (7) through pipelines, respectively, the mixing fan (7) is connected to the fresh air mechanism and the heating mechanism through pipelines, the heating mechanism is connected to a plurality of ovens (12) in parallel through pipelines, a part of the ovens (12) is connected to the RTO device (2) through pipelines, and another part of the ovens (12) is connected to the hot air pressure fan A (1) in series through pipelines.

2. The RTO hot air waste heat recovery system for coating according to claim 1, characterized in that: An RTO hot air valve (5) is provided in series on the pipeline between the RTO hot air heat exchanger (3) and the mixing fan (7).

3. The RTO hot air waste heat recovery system for coating according to claim 2, characterized in that: A fresh air valve A (6) is provided in series on the pipeline between the fresh air mechanism and the mixing fan (7).

4. The RTO hot air waste heat recovery system for coating as claimed in claim 3, characterized in that: A hot air pressurizing blower B (4) is arranged in series on the pipeline between the RTO hot air heat exchanger (3) and the RTO hot air valve (5).

5. The RTO hot air waste heat recovery system according to any one of claims 1 to 4, characterized in that: A temperature detection unit (11) is provided on the pipeline between the mixing fan (7) and the heating mechanism.

6. The RTO hot air waste heat recovery system for coating according to claim 1, characterized in that: The fresh air mechanism is connected to the pipeline between the mixing fan (7) and the heating mechanism via a secondary pipe (15), and a fresh air valve B (8) is provided in series on the secondary pipe (15).

7. The RTO hot air waste heat recovery system for coating according to claim 1, characterized in that: An exhaust fan (13) and an exhaust valve (14) are arranged in series on the pipeline connecting the oven (12) and the hot air pressure fan A (1).

8. The RTO hot air waste heat recovery system for coating according to claim 1, characterized in that: The heating mechanism comprises a steam heater (9) and an auxiliary electric heater (10).

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