Device for treating tail gas containing small amount of VOCS

Abstract

The utility model relates to a device for treating tail gas containing a small amount of VOCS. Comprising a tail gas pipeline containing a small amount of VOCS, the tail gas pipeline containing the small amount of VOCS is connected with an inlet of a separation filter through a first tee joint, and a gas phase outlet of the separation filter is connected with an exhaust funnel through a catalytic reactor; the third end of the first tee joint is connected with an air pipeline with a Roots blower; according to the arrangement, VOCS gas can be removed on the premise that auxiliary fuel is not added and open fire is not generated, so that the advantages that cost and energy consumption are reduced, equipment investment is reduced, the overall layout of a plant is not affected, and maximum utilization of land of the plant is achieved are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas treatment containing VOCS, in particular to a tail gas treatment device containing a small amount of VOCS. Background Art

[0002] At present, in the process of harmless treatment of VOCS waste gas, the production method of harmless treatment of VOCS waste gas mainly adopts the combustion method; the traditional combustion method mainly burns a large amount of VOCS waste gas, and the reaction temperature is greater than 800°C. Based on this, the requirements for equipment materials are relatively high, resulting in expensive equipment prices; further, due to the combustion of VOCS waste gas, the VOCS waste gas needs to have a high concentration, and auxiliary fuel is added to enter the combustion furnace for direct combustion; when the VOCS waste gas is at a low concentration, a large amount of auxiliary fuel is required, which has the defects of high cost and energy consumption. At the same time, there is an open flame in the oxidation reaction of the combustion method, and the fire protection distance with other devices is large, which affects the overall layout of the plant and the land cannot be maximized. Utility Model Content

[0003] The utility model aims to provide an exhaust gas treatment device containing a small amount of VOCS to solve the problems raised in the above background technology.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A tail gas treatment device containing a small amount of VOCS comprises a tail gas pipeline containing a small amount of VOCS, wherein the tail gas pipeline containing a small amount of VOCS is connected to the inlet of a separation filter through a first tee, and the gas phase outlet of the separation filter is connected to an exhaust pipe through a catalytic reactor; the third end of the first tee is connected to an air pipeline with a Roots blower.

[0006] The beneficial effects of the utility model are as follows: the utility model achieves the purpose of stabilizing the VOCS concentration by arranging the first three-way valve to mix the tail gas of the VOCS with the air, thereby laying a foundation for the subsequent continuous and stable treatment process; further, the physical removal of water and particulate matter can be achieved by arranging the separation filter, laying a foundation for the oxidation reaction of the VOCS using a catalytic reactor in the subsequent process; the above-mentioned arrangement can remove the VOCS gas without adding auxiliary fuel and without generating open flames, so as to reduce costs and energy consumption, reduce equipment investment, and not affect the overall layout of the plant area, thereby maximizing the utilization of the plant area land.

[0007] Preferably, a first bellows is provided between the air duct and the inlet of the Roots blower, and a second bellows is provided between the outlet of the Roots blower and the third end of the first tee.

[0008] Preferably, the catalytic reactor is a catalytic reactor using a palladium catalyst.

[0009] Preferably, the catalytic reactor is connected to the exhaust pipe via a first heat exchange channel of a heat exchanger.

[0010] Preferably, a second tee, a second regulating valve and a third tee are provided in sequence between the gas phase outlet of the separation filter and the catalytic reactor, the third end of the second tee is connected to the second heat exchange channel of the heat exchanger, and the outlet of the second heat exchange channel of the heat exchanger is connected to the third end of the third tee through electric heating.

[0011] Preferably, a first regulating valve is provided between the tail gas pipeline containing a small amount of VOCS and the first three-way connection.

[0012] Preferably, three catalyst reaction beds are arranged in the catalytic reactor, and temperature sensors are respectively arranged at corresponding positions of the three catalyst reaction beds.

[0013] According to the above scheme, a tail gas treatment device containing a small amount of VOCS is made. By adopting a catalytic oxidation process, under certain temperature conditions, a mixed gas containing a small amount of VOCS (methanol, carbon monoxide, alkanes, etc.) is passed through a catalytic oxidation reactor at a certain rate, organic matter and oxygen are enriched on the catalyst surface, and the reaction begins at low temperature. The organic matter is oxidized into non-toxic, odorless, and non-secondary pollution carbon dioxide and water. The utility model has the following advantages: 1. The utility model uses a palladium catalyst to provide an active reaction center, effectively reducing the initial reaction temperature of the medium to 300°C. The equipment uses ordinary carbon steel material to meet the requirements and significantly reduce the equipment cost. 2. The bed layer of the catalyst in the catalytic reactor is provided with three temperature detection points, and a control loop is formed with the start and stop of the Roots blower. Through the variable frequency regulation of the Roots blower, the VOCS content of the tail gas entering the catalytic reactor is stabilized, and the treatment of trace VOCS tail gas is achieved; the high-temperature gas after the catalytic oxidation reaction is recovered through the heat exchanger, and only the blower consumes electricity during normal operation, and the energy consumption is lower. 3. The oxidation reaction of the device has no open flames, and the fire protection distance with other devices is reduced, making the overall layout of the plant more reasonable and effectively improving the land utilization rate. 4. The inlet and outlet pipes of the Roots blower are equipped with bellows. When the gas flows through the pipe, due to the special structure of the bellows compensator, pressure waves will be generated inside the pipe. These pressure waves will further cause the elastic deformation of the bellows compensator. These elastic deformations effectively absorb the vibration of the transmission equipment and reduce the impact on nearby stationary equipment and pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model.

[0015] In the figure: 1. Roots blower; 2. separation filter; 3. catalytic reactor; 4. electric heating; 5. heat exchanger; 6. exhaust pipe; 7. first regulating valve; 8. second regulating valve; 9. first tee; 10. exhaust pipe containing a small amount of VOCS; 11. air pipe; 12. second tee; 13. third tee; 14. temperature sensor; 15. first bellows; 16. second bellows. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0017] Reference Figure 1 As shown, the utility model provides an exhaust gas treatment device containing a small amount of VOCS, including an exhaust gas pipeline 10 containing a small amount of VOCS, wherein the exhaust gas pipeline 10 containing a small amount of VOCS is connected to the inlet of the separation filter 2 through a first tee 9, and the gas phase outlet of the separation filter 2 is connected to the exhaust pipe 6 through a catalytic reactor 3; the third end of the first tee 9 is connected to an air duct 11 with a Roots blower 1. It should be noted that the exhaust gas containing a small amount of VOCS described in the utility model refers to a concentration of 200ppm to 1%; the utility model abandons the form of using combustion method to treat VOCS exhaust gas in traditional technology, and adopts a catalytic oxidation process. Under certain temperature conditions, a mixed gas containing a small amount of VOCS (methanol, carbon monoxide, alkanes, etc.) is passed through a catalytic oxidation reactor at a certain rate, and organic matter and oxygen are enriched on the catalyst surface. The reaction starts at a low temperature, and the organic matter is oxidized into non-toxic, odorless, and non-secondary pollution carbon dioxide and water, so as to achieve the purpose of removing VOCS from the exhaust gas containing a small amount of VOCS; specifically For example, by setting up the Roots blower 1, the air and the exhaust gas containing a small amount of VOCS can be mixed to achieve the purpose of stabilizing the VOCS concentration, laying a foundation for the subsequent continuous and stable treatment process. Furthermore, by setting up the separation filter 2, the physical removal of water and particulate matter can be achieved, laying a foundation for the use of the catalytic reactor 3 to oxidize VOCS in the subsequent process; the above-mentioned setting can remove VOCS gas without adding auxiliary fuel and without generating open flames, so as to reduce costs and energy consumption, reduce equipment investment, and not affect the overall layout of the plant, thereby maximizing the use of plant land.

[0018] Furthermore, a first bellows 15 is provided between the air duct 11 and the inlet of the Roots blower 1, and a second bellows 16 is provided between the outlet of the Roots blower 1 and the third end of the first tee 9. The utility model can achieve that when the gas flows through the pipeline, due to the particularity of the structure of the bellows compensator, pressure waves are generated inside the pipeline, and these pressure waves further cause elastic deformation of the bellows compensator. These elastic deformations effectively absorb the vibration of the transmission equipment, reduce the impact on nearby stationary equipment and pipelines, and achieve long-term stable operation of the equipment by providing the first bellows 15 and the second bellows 16.

[0019] Furthermore, the catalytic reactor 3 is a catalytic reactor using a palladium catalyst. The utility model preferably uses a catalytic reactor using a palladium catalyst, which provides an active reaction center with a palladium catalyst, effectively reducing the initial reaction temperature of the medium to 300°C. The equipment uses ordinary carbon steel material to meet the requirements and significantly reduce the equipment cost. At the same time, the oxidation reaction has no open flames, and the fire protection distance with other devices is reduced, making the overall layout of the plant more reasonable and effectively improving the land utilization rate.

[0020] Furthermore, the catalytic reactor 3 is connected to the exhaust pipe 6 through the first heat exchange channel of the heat exchanger 5. A second three-way 12, a second regulating valve 8 and a third three-way 13 are provided between the gas phase outlet of the separation filter 2 and the catalytic reactor 3 in sequence, the third end of the second three-way 12 is connected to the second heat exchange channel of the heat exchanger 5, and the outlet of the second heat exchange channel of the heat exchanger 5 is connected to the third end of the third three-way 13 through the electric heater 4. The above arrangement can realize the utilization of the waste heat after the oxidation reaction in the catalytic reactor 3.

[0021] Furthermore, a first regulating valve 7 is provided between the tail gas pipeline 10 containing a small amount of VOCS and the first three-way valve 9 .

[0022] Furthermore, three catalyst reaction beds are provided in the catalytic reactor 3, and temperature sensors 14 are respectively provided at corresponding positions of the three catalyst reaction beds. The catalyst bed of the catalytic reactor is provided with three temperature detection points, and forms a control loop with the start and stop of the Roots blower. Through the variable frequency regulation of the Roots blower, the VOCS content of the tail gas entering the catalytic reactor is stabilized, so as to achieve the treatment of trace VOCS tail gas.

[0023] The working principle of the utility model includes the following steps: Step 1: The Roots blower 1 pressurizes the air and mixes it with the tail gas containing a small amount of VOCS. The Roots blower 1 pressurizes the air to 2000pa and mixes it with the tail gas containing a small amount of VOCS; the Roots blower 1 is frequency-controlled, and the VOCS concentration is stable after mixing. Step 2: The mixed gas of part of the air and tail gas in step 1 is connected to the exhaust pipe 6 through the separation filter 2, the third end of the second three-way 12, the second regulating valve 8, the third three-way 13, the catalytic reactor 3, and the first heat exchange channel of the heat exchanger 5 in sequence; the separation filter 2 removes physical impurities such as water and particulate matter in the filter, and the removal rate reaches 80%. Step 3: The mixed gas of air and tail gas in step 2 enters the catalytic reactor 3, and the hydrocarbons, methanol, carbon monoxide in the mixed gas and the oxygen in the air undergo oxidation reaction in the catalyst bed and are converted into non-toxic, odorless, and non-secondary pollution carbon dioxide and water. The normal operating temperature of the catalytic reactor 3 is 400-535°C. According to the actual measured temperatures at temperature detection points 1, 2 and 3, the Roots blower is automatically adjusted through PLC control analysis. After the oxidation reaction of the catalyst bed occurs, the removal rate of non-methane total hydrocarbons is ≥97%, and the non-methane total hydrocarbons are ≤20mg / m 3 , hydrogen and carbon monoxide emission concentration: ≤1mg / m 3 ; No nitrogen oxide and sulfide emissions, VOCs ≤ 0.4t / a. Step 4: The air and exhaust gas mixture in step 2 passes through the catalytic reactor 3 and enters the first heat exchange channel of the heat exchanger; the catalytic reaction in the catalytic reactor is an exothermic reaction, and the gas at the first inlet of the heat exchanger serves as the heat measurement fluid. Step 5: Another part of the air and exhaust gas mixture in step 1 is connected to the third end of the third tee 13 through the second end of the second tee 12, the second heat exchange channel of the heat exchanger, and the electric heater 4 in sequence; the mixed gas in the second heat exchange channel of the heat exchanger serves as the cold side fluid, exchanges heat with the heat measurement fluid in step 4, and performs heat recovery during normal operation, which can reduce the power consumption of the electric heater 4 by more than 90%.

[0024] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A tail gas treatment device containing a small amount of VOCS, comprising a tail gas pipeline (10) containing a small amount of VOCS, characterized in that: The tail gas pipeline (10) containing a small amount of VOCS is connected to the inlet of the separation filter (2) through the first three-way connection (9), and the gas phase outlet of the separation filter (2) is connected to the exhaust pipe (6) through the catalytic reactor (3); The third end of the first three-way connection (9) is connected to an air duct (11) having a Roots blower (1).

2. The tail gas treatment device containing a small amount of VOCS according to claim 1, characterized in that: A first bellows (15) is provided between the air duct (11) and the inlet of the Roots blower (1), and a second bellows (16) is provided between the outlet of the Roots blower (1) and the third end of the first tee (9).

3. The tail gas treatment device containing a small amount of VOCS according to claim 1, characterized in that: The catalytic reactor (3) is a catalytic reactor using a palladium catalyst.

4. The tail gas treatment device containing a small amount of VOCS according to claim 1, characterized in that: The catalytic reactor (3) and the exhaust pipe (6) are connected via a first heat exchange channel of a heat exchanger (5).

5. The tail gas treatment device containing a small amount of VOCS according to claim 4, characterized in that: A second tee (12), a second regulating valve (8) and a third tee (13) are provided in sequence between the gas phase outlet of the separation filter (2) and the catalytic reactor (3); the third end of the second tee (12) is connected to the second heat exchange channel of the heat exchanger (5); and the outlet of the second heat exchange channel of the heat exchanger (5) is connected to the third end of the third tee (13) via an electric heater (4).

6. The tail gas treatment device containing a small amount of VOCS according to claim 1, characterized in that: A first regulating valve (7) is provided between the tail gas pipeline (10) containing a small amount of VOCS and the first three-way valve (9).

7. The tail gas treatment device containing a small amount of VOCS according to claim 1 or 3, characterized in that: Three catalyst reaction beds are arranged in the catalytic reactor (3), and temperature sensors (14) are respectively arranged at corresponding positions of the three catalyst reaction beds.

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