Aluminum veneer spraying line exhaust gas treatment method

Abstract

The present application belongs to the technical field of aluminum veneer processing, and particularly relates to a kind of aluminum veneer spraying line waste gas treatment method, comprising the following steps: normal temperature low concentration waste gas containing organic matter is removed 1-5um dust after passing through 4-stage filter box by each exhaust fan through valve or frequency converter control appropriate air volume, and then enters molecular sieve runner, when waste gas passes through molecular sieve bed layer installed in runner, low boiling point organic matter is fully adsorbed in micropore of molecular sieve, and standard large air volume clean gas is discharged into atmosphere through chimney; with the slow rotation of runner, when molecular sieve reaches the set adsorption amount, one of the partitions enters desorption area.The present application can burn and decompose organic waste gas into clean water and carbon dioxide high-temperature gas, and through automatic temperature adjusting device, high-temperature gas is sent to solidification furnace again as auxiliary heat energy to solidify products, so that the effect of energy saving is achieved.

Description

Technical Field

[0001] This invention relates to the field of aluminum panel processing technology, and in particular to a method for treating exhaust gas from an aluminum panel spraying line. Background Technology

[0002] Considering the durability of building products, most aluminum composite panels use fluorocarbon liquid paint. All of these paints require high-temperature baking and curing. Liquid paints contain more than 30% toxic and harmful organic solvents, mainly toluene, xylene, ketones, and esters, which produce organic solvent gases during baking.

[0003] Traditional baking processes, due to cost considerations and a lack of environmental awareness, produce organic gases that are directly emitted, resulting not only in environmental pollution but also in a waste of energy.

[0004] Therefore, we propose a waste gas treatment method for aluminum single-panel spraying lines to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for treating exhaust gas from aluminum single-panel spraying lines.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for treating exhaust gas from an aluminum single-panel coating line includes the following steps:

[0008] S1. Low-concentration exhaust gas containing organic matter at room temperature passes through each exhaust fan and is controlled by valves or frequency converters to remove 1-5μm dust. Then it enters the molecular sieve rotor. When the exhaust gas passes through the molecular sieve bed installed in the rotor, the low-boiling-point organic matter is fully adsorbed in the micropores of the molecular sieve. The qualified large-volume clean gas is discharged into the atmosphere through the chimney.

[0009] S2. As the rotor slowly rotates, when the molecular sieve reaches the set adsorption capacity, one of the zones enters the desorption zone. 180°C hot air is introduced through the desorption channel to desorb the organic matter adsorbed in the micropores of the molecular sieve. The desorbed gas containing organic matter and high temperature is sent to the regenerator oxidizer for high-temperature combustion and decomposition into non-toxic and harmless carbon dioxide and water, and further releases heat.

[0010] S3. The organic waste gas entering the regenerator first passes through the regenerator for preheating, and then enters the oxidation chamber for heating to 830°C, so that the VOCs in the waste gas are oxidized and decomposed into carbon dioxide and water. The oxidized high-heat gas then passes through another regenerator for heat storage treatment, and then the flue gas is discharged from the regenerator.

[0011] S4. When the heat released by the organic matter is sufficient to maintain the heat of the regenerator in the regenerator, the entire operating equipment reaches the optimal reactive operating state and does not require the consumption of natural gas. When the heat released by the organic matter is insufficient to maintain the heat of the regenerator in the regenerator, the matching burner starts and supplements the heat by burning natural gas to ensure that the treated gas meets the emission standards.

[0012] In the above-mentioned waste gas treatment method for aluminum single-panel spraying line, the gas enters the molecular sieve rotor for 25-fold concentration in step S1; the molecular sieve treatment efficiency is 90%, and after the above process, the total non-methane hydrocarbons in the exhaust gas are reduced to ≤50mg / m3 to meet the emission standards.

[0013] In the above-mentioned exhaust gas treatment method for aluminum single-panel spraying line, the dust content of the gas entering the rotor after passing through the 4-stage filter box in step S1 must be less than 100ppm, and the particle size must be less than 1um, which is smaller than the ventilation aperture of the molecular sieve, to ensure that these particles do not accumulate on the surface of the molecular sieve and play a role in stabilizing the concentration treatment effect.

[0014] In the above-mentioned method for treating exhaust gas from aluminum single-panel spraying lines, in step S2, as the amount of organic matter adsorbed by the molecular sieve in the rotor gradually increases, a portion of the high-temperature gas from the regenerator oxidizer is extracted to heat the fresh air. The molecular sieve entering the desorption zone is then desorbed at high temperature through the desorption gas duct. The organic matter is gradually desorbed into a gaseous state at 180°C and sent into the regenerator oxidizer along with the desorbed gas to be incinerated at high temperature together with the oven exhaust gas, decomposing into non-toxic and harmless carbon dioxide and water and releasing heat.

[0015] In the above-mentioned exhaust gas treatment method for aluminum single-panel spraying line, the air volume of the heated fresh air is 1 / 25 of the treatment air volume, and the fresh air temperature is heated to a set 180°C.

[0016] In the above-mentioned exhaust gas treatment method for aluminum single-panel spraying line, the process in step S3 is continuously cyclical and regenerated. Each heat storage chamber alternates between the input of exhaust gas and the output of treated gas, and the switching time can be adjusted according to the actual situation.

[0017] In the above-mentioned exhaust gas treatment method for aluminum single-panel spraying line, the regenerative oxidizer in step S2 includes a first regenerative chamber, a second regenerative chamber, a third regenerative chamber, a first combustion chamber, and a second combustion chamber. The specific steps for using the regenerative oxidizer include:

[0018] (1) The organic waste gas first enters the first heat storage chamber under the action of the blower, absorbs heat and then enters the first combustion chamber. The first heat storage chamber cools down due to heat release. The gas heated by combustion enters the second heat storage chamber, stores the heat in the ceramic heat storage body of the second heat storage chamber through heat exchange, and then is discharged.

[0019] (2) At the same time, the residual untreated organic waste gas in the third regenerator space is back-blown back to the first combustion chamber for incineration after purification. After a certain period of time, the airflow changes direction and enters the second combustion chamber from the second regenerator. After absorbing heat and heating up in the second regenerator, it is decomposed at high temperature in the furnace and finally discharged after heat exchange in the third regenerator.

[0020] (3) At the same time, the first heat storage chamber is in a backflushing state. After a period of time, the airflow changes direction again and continuously alternates and circulates to ensure that the combustion chamber temperature is above 800℃.

[0021] Compared with existing technologies, the advantages of this aluminum single-panel spraying line exhaust gas treatment method are:

[0022] This invention collects organic solvent gases (toluene, xylene, ketones, and esters) from paint and directly burns the collected low-concentration organic waste gas after heat storage. The combustion equipment heats the organic waste gas to the oxidation and decomposition temperature of organic matter, 800°C, causing the organic waste gas to burn and decompose into clean water and high-temperature carbon dioxide gas. The high-temperature gas is then sent back to the curing oven as auxiliary heat energy to cure the product through an automatic temperature regulation device, thereby achieving energy-saving effects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process structure of an aluminum single-panel spraying line exhaust gas treatment method proposed in this invention.

[0024] Figure 2 This is a structural diagram of the regenerator oxidizer in an aluminum single-panel spraying line exhaust gas treatment method proposed in this invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] Reference Figure 1-2 A method for treating exhaust gas from an aluminum single-panel coating line includes the following steps:

[0027] S1. Low-concentration exhaust gas containing organic matter at room temperature passes through each exhaust fan and is controlled by valves or frequency converters to remove 1-5μm dust. Then it enters the molecular sieve rotor. When the exhaust gas passes through the molecular sieve bed installed in the rotor, the low-boiling-point organic matter is fully adsorbed in the micropores of the molecular sieve. The qualified large-volume clean gas is discharged into the atmosphere through the chimney.

[0028] S2. As the rotor slowly rotates, when the molecular sieve reaches the set adsorption capacity, one of the zones enters the desorption zone. 180°C hot air is introduced through the desorption channel to desorb the organic matter adsorbed in the micropores of the molecular sieve. The desorbed gas containing organic matter and high temperature is sent to the regenerator oxidizer for high-temperature combustion and decomposition into non-toxic and harmless carbon dioxide and water, and further releases heat.

[0029] S3. The organic waste gas entering the regenerator first passes through the regenerator for preheating, and then enters the oxidation chamber for heating to 830°C, so that the VOCs in the waste gas are oxidized and decomposed into carbon dioxide and water. The oxidized high-heat gas then passes through another regenerator for heat storage treatment, and then the flue gas is discharged from the regenerator.

[0030] S4. When the heat released by the organic matter is sufficient to maintain the heat of the regenerator in the regenerator, the entire operating equipment reaches the optimal reactive operating state and does not require the consumption of natural gas. When the heat released by the organic matter is insufficient to maintain the heat of the regenerator in the regenerator, the matching burner starts and supplements the heat by burning natural gas to ensure that the treated gas meets the emission standards.

[0031] In step S1, the gas enters the molecular sieve rotor and is concentrated 25 times. The molecular sieve has a treatment efficiency of 90%. After the above process, the total non-methane hydrocarbons in the exhaust gas are reduced to ≤50mg / m3, meeting the emission standards. Specifically, in step S1, the dust content of the gas entering the rotor after passing through the 4-stage filtration box must be less than 100ppm, and the particle size must be less than 1um, which is smaller than the ventilation aperture of the molecular sieve. This ensures that these particles do not accumulate on the surface of the molecular sieve, thus stabilizing the concentration treatment effect. Specifically, the 4-stage filtration set in the rotor pretreatment includes a single-layer primary filter cotton, a primary filter G4, a medium-efficiency filter F7, and a high-efficiency filter F9. The pretreatment filter is mainly used to remove sticky substances and dust that are harmful to the rotor. The primary filter cotton and the primary filter are used to remove dust and sticky substances larger than 5um in the exhaust gas. The medium-efficiency filter is used to remove dust and sticky substances larger than 2um in the exhaust gas. The high-efficiency filter is used to remove dust and sticky substances larger than 1um in the exhaust gas. A differential pressure gauge is also installed. When a certain pressure is reached, the control system will issue a prompt message, and the filter material needs to be replaced in time.

[0032] In step S2, as the amount of organic matter adsorbed by the molecular sieve in the rotor gradually increases, a portion of the high-temperature gas from the regenerator oxidizer is extracted to heat the fresh air. The molecular sieve entering the desorption zone is then desorbed at high temperature through the desorption gas duct. Specifically, the volume of the heated fresh air is 1 / 25 of the processing air volume, and the fresh air temperature is heated to a set 180°C. The organic matter is gradually desorbed into a gaseous state at the high temperature of 180°C and sent into the regenerator oxidizer along with the desorbed gas to be incinerated at high temperature together with the oven exhaust gas, decomposing into non-toxic and harmless carbon dioxide and water and releasing heat.

[0033] In step S3, the process is continuously cyclical and regenerated. Each heat storage chamber alternates between the input of waste gas and the output of treated gas, and the switching time can be adjusted according to the actual situation.

[0034] Reference Figure 2 The regenerative oxidizer in step S2 includes a first regenerative chamber, a second regenerative chamber, a third regenerative chamber, a first combustion chamber, and a second combustion chamber. The specific steps for using the regenerative oxidizer include:

[0035] (1) The organic waste gas first enters the first heat storage chamber under the action of the blower, absorbs heat and then enters the first combustion chamber. The first heat storage chamber cools down due to heat release. The gas heated by combustion enters the second heat storage chamber, stores the heat in the ceramic heat storage body of the second heat storage chamber through heat exchange, and then is discharged.

[0036] (2) At the same time, the residual untreated organic waste gas in the third regenerator space is back-blown back to the first combustion chamber for incineration after purification. After a certain period of time, the airflow changes direction and enters the second combustion chamber from the second regenerator. After absorbing heat and heating up in the second regenerator, it is decomposed at high temperature in the furnace and finally discharged after heat exchange in the third regenerator.

[0037] (3) At the same time, the first heat storage chamber is in a backflushing state. After a period of time, the airflow changes direction again and continuously alternates and circulates to ensure that the combustion chamber temperature is above 800℃.

[0038] Specifically, the heating capacity of each combustion chamber is automatically adjusted by a PID controller based on the temperature feedback signal inside the furnace. In addition, the combustion system also has functions such as automatic pre-purge before ignition, flameout protection, over-temperature alarm, and automatic fuel supply cut-off when over-temperature occurs.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for treating exhaust gas from an aluminum single-panel coating line, characterized in that, Includes the following steps: S1. Low-concentration exhaust gas containing organic matter at room temperature passes through each exhaust fan and is controlled by valves or frequency converters to remove 1-5μm dust. Then it enters the molecular sieve rotor. When the exhaust gas passes through the molecular sieve bed installed in the rotor, the low-boiling-point organic matter is fully adsorbed in the micropores of the molecular sieve. The qualified large-volume clean gas is discharged into the atmosphere through the chimney. S2. As the rotor slowly rotates, when the molecular sieve reaches the set adsorption capacity, one section enters the desorption zone. Hot air at 180°C is introduced through the desorption channel to desorb the organic matter adsorbed in the micropores of the molecular sieve. The desorbed, high-concentration gas containing organic matter is sent to the regenerative oxidizer for high-temperature combustion and decomposition into non-toxic and harmless carbon dioxide and water, further releasing heat. The regenerative oxidizer in step S2 includes a first regenerative chamber, a second regenerative chamber, a third regenerative chamber, a first combustion chamber, and a second combustion chamber. The specific steps of using the regenerative oxidizer include: (1) The organic waste gas first enters the first heat storage chamber under the action of the blower, absorbs heat and then enters the first combustion chamber. The first heat storage chamber cools down due to heat release. The gas heated by combustion enters the second heat storage chamber, stores the heat in the ceramic heat storage body of the second heat storage chamber through heat exchange, and then is discharged. (2) At the same time, the residual untreated organic waste gas in the third regenerator space is back-blown back to the first combustion chamber for incineration after purification. After a certain period of time, the airflow changes direction and enters the second combustion chamber from the second regenerator. After absorbing heat and heating up in the second regenerator, it is decomposed at high temperature in the furnace and finally discharged after heat exchange in the third regenerator. (3) At the same time, the first heat storage chamber is in a backflushing state. After a period of time, the airflow changes direction again and continuously alternates and circulates to ensure that the combustion chamber temperature is above 800℃. S3. The organic waste gas entering the regenerator first passes through the regenerator for preheating, and then enters the oxidation chamber for heating to 830°C, so that the VOCs in the waste gas are oxidized and decomposed into carbon dioxide and water. The oxidized high-heat gas then passes through another regenerator for heat storage treatment, and then the flue gas is discharged from the regenerator. S4. When the heat released by the organic matter is sufficient to maintain the heat of the regenerator in the regenerator, the entire operating equipment reaches the optimal reactive operating state and does not require the consumption of natural gas. When the heat released by the organic matter is insufficient to maintain the heat of the regenerator in the regenerator, the matching burner starts and supplements the heat by burning natural gas to ensure that the treated gas meets the emission standards.

2. The method for treating exhaust gas from an aluminum single-panel spraying line according to claim 1, characterized in that, In step S1, the gas enters a molecular sieve rotor for 25-fold concentration; the molecular sieve treatment efficiency is 90%, and after treatment by the above method, the total non-methane hydrocarbons in the exhaust gas are reduced to ≤50mg / m3, meeting the emission standards.

3. The method for treating exhaust gas from an aluminum single-panel spraying line according to claim 2, characterized in that, In step S1, the dust content of the gas entering the rotor after passing through the 4-stage filtration box must be less than 100 ppm, and the particle size must be less than 1 μm, which is smaller than the ventilation aperture of the molecular sieve. This ensures that these particles do not accumulate on the surface of the molecular sieve, thus playing a role in stabilizing the concentration treatment effect.

4. The method for treating exhaust gas from an aluminum single-panel spraying line according to claim 1, characterized in that, In step S2, as the amount of organic matter adsorbed by the molecular sieve in the rotor gradually increases, a portion of the high-temperature gas from the regenerator oxidizer is extracted to heat the fresh air. The molecular sieve entering the desorption zone is then desorbed at high temperature through the desorption gas duct. The organic matter is gradually desorbed into a gaseous state at 180°C and sent into the regenerator oxidizer along with the desorbed gas to be incinerated at high temperature together with the oven exhaust gas, decomposing into non-toxic and harmless carbon dioxide and water and releasing heat.

5. The method for treating exhaust gas from an aluminum single-panel spraying line according to claim 4, characterized in that, The volume of the heated fresh air is 1 / 25 of the processing air volume, and the temperature of the fresh air is heated to a set 180°C.

6. The method for treating exhaust gas from an aluminum single-panel spraying line according to claim 5, characterized in that, The process described in step S3 is a continuous cycle of regeneration. Each heat storage chamber alternates between the input of waste gas and the output of treated gas, and the switching time is adjusted according to the actual situation.

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