WO2020199145A1 - Vocs waste gas treatment system - Google Patents

Abstract

A VOCs waste gas treatment system, consisting of two subsystems which are respectively a circulation system and a discharge system: the circulation system comprising a waste gas source (1), an air supply circulation pipeline (23), an air return circulation pipeline (21), a circulation fan (3), a first flow division valve (41), a gas inlet device (6), an air quality detection device (71), and a central information processing control device (13), and the discharge system comprising a discharge pipeline (8), a VOCs waste gas processing device (5), and a gas exhaust device (9), wherein an inlet of the discharge pipeline (8) is connected to the air supply circulation pipeline (23) by means of the first flow division valve (41); the discharge pipeline (8) is provided with the gas exhaust device (9) and is connected to the VOCs waste gas processing device (5); and the central information processing control device (13) is electrically connected to the air quality detection device (71), the first flow division valve (41), and the VOCs waste gas processing device (5). The waste gas treatment system can reduce the air volume entering the VOCs waste gas processing device (5) and improve the concentration of the waste gas, thereby reducing the difficulty of treatment and reducing the discharge of the VOCs waste gas.

Description

A VOCs exhaust gas treatment system Technical field

The invention relates to the technical field of environmental protection treatment, in particular to a VOCs waste gas treatment method, in particular to a VOCs waste gas treatment system.

Background technique

In the production process of the printing industry, printing equipment such as printing presses, laminating machines, coating machines, and jet dyeing machines will produce a large amount of volatile organic gases such as ethanol, ethyl acetate, butyl acetate, propyl acetate, and toluene and xylene. The main processes of waste gas generation are inking, drying, and compounding. The organic solvents volatilized during the period are the main source of waste gas pollution. If these VOCs exhaust gas cannot be properly treated, it will seriously endanger human health and the environment. The methods widely used in the treatment of waste gas in the printing industry mainly include adsorption-regeneration method, absorption separation method and oxidation destruction method. However, in the prior art, since the adsorption method widely uses activated carbon as the adsorbent, when the adsorption reaches the saturation of VOCs, the activated carbon needs to be desorbed by hot air, steam or pressure swing. In the desorption process, a large amount of air volume needs to be processed, and the energy consumption is huge. Therefore, it is necessary to design a VOCs exhaust gas treatment system that requires less air volume and low energy consumption.

Summary of the invention

The technical problem to be solved by the present invention is to provide a VOCs waste gas treatment system, which needs to process less air volume and saves energy consumption.

In order to solve the above technical problems, the technical solution of the present invention is:

A VOCs exhaust gas treatment system is composed of two sub-systems respectively a circulation system and an external exhaust system, the circulation system is connected to the external exhaust system: the circulation system includes an exhaust gas source, a supply air circulation pipe, and a return air The circulation duct, the circulation fan, the first shunt valve, the air intake device, the air quality detection device and the central information processing control device, the circulation fan is arranged in the air supply circulation duct and the return air circulation duct, and the delivery The air circulation pipe and the return air circulation pipe are connected to the exhaust gas source, the air quality detection device is arranged in the circulation pipe far away from the exhaust gas source, and the external exhaust system includes an external exhaust pipe, VOCs exhaust gas treatment equipment and exhaust Device, the inlet of the outer discharge pipeline is connected to the circulation pipeline through the first shunt valve, the outer discharge pipeline is provided with an exhaust device and is connected to the VOCs exhaust gas treatment equipment, and the central information processing control The device is electrically connected to the air quality detection device, the first shunt valve and the VOCs exhaust gas treatment equipment.

Preferably, the VOCs waste gas treatment equipment is one or a combination of RTO combustion device, RCO combustion device, activated carbon adsorption device, condensation recovery device and plasma decomposition device.

When the VOCs waste gas source needs to use hot air for drying during the working process, the VOCS waste gas treatment equipment of this system preferably uses combustion devices such as RTO or RCO, and each section of the pipeline is a pipeline for thermal insulation treatment.

Preferably, the first diverter valve is a three-way valve whose inlet is connected to a return air circulation pipe, its first outlet is connected to the air intake device, and its second outlet is connected to the VOCs exhaust gas treatment equipment, which will enter the The exhaust gas volume percentage of the external exhaust system is controlled within the range of 5%-50%.

When the air quality detection device detects that the VOCs exhaust gas concentration does not reach an excessive level, the central information processing control device controls the first shunt valve so that the gas is in a state of complete internal circulation and does not enter the VOCs exhaust gas treatment equipment.

When the air quality detection device detects that the concentration of VOCs exhaust gas reaches a preset level, the central information processing control device controls the first shunt valve so that the gas enters the VOCs exhaust gas treatment equipment for treatment. After the treatment reaches the standard level, the exhaust gas is discharged Into the atmosphere; at this time, the gas in the circulation system decreases and the air pressure drops, the central information processing control device instructs the air intake device to add fresh air to the air circulation duct to dilute the VOCs exhaust gas.

Preferably, the circulation system further includes a second split valve and a waste heat recovery device, the inlet of the second split valve is connected to the air intake device, the first outlet is connected to the air quality detection device, and the second outlet is connected to the waste heat. The waste heat recovery device is provided with two inlets and two outlets. The first inlet of the waste heat recovery device is connected to the outlet of the exhaust gas treatment equipment, and the second inlet of the waste heat recovery device is connected to the second outlet of the second split valve. The first outlet of the recovery device is connected to the exhaust device, and the second outlet of the waste heat recovery device is connected to the air quality detection device.

After the RTO or RCO treatment equipment processes the gas that meets the standard, the temperature will reach 400°C to 1200°C. Before these gases are discharged into the atmosphere, they pass through the waste heat recovery device to exchange heat into the circulating gas in the circulation system for production, which has the effect of reducing waste, energy saving, and emission reduction.

Preferably, it further includes an air quality adjustment device and an explosion-proof device. One end of the air quality adjustment device is connected to the air quality detection device, and the other end is connected to the first outlet of the second shunt valve, and the explosion-proof device is arranged at On the pipeline between the first shunt valve and the VOCs exhaust gas treatment equipment.

During the operation of the entire system, the VOCS exhaust gas source continuously produces VOCS exhaust gas, the intake device continuously adds fresh air, and the diverter valve continuously diverts part of the exhaust gas to the VOCS treatment equipment for processing and discharges to the atmosphere. In the end, the VOCS exhaust gas concentration in the circulation pipeline will be dynamically stabilized within the set concentration range.

With the above technical solution, the VOCs exhaust gas treatment system is equipped with the first shunt valve, the air intake device and the air quality detection device, which are electrically connected to the central information processing control device. The central information processing control device adjusts the air intake device and the first shunt Valve, adjust and add fresh air to dilute the VOCs exhaust gas, so that the concentration of exhaust gas flowing through the VOCs exhaust gas treatment equipment can be increased, and the exhaust gas flow rate can be reduced, thereby reducing the energy consumption of the VOCs exhaust gas treatment equipment. In addition, the establishment of the waste heat recovery device allows the heat in the waste gas treatment process to be recovered and reused, achieving the effect of energy saving and environmental protection.

Description of the drawings

Fig. 1 is a schematic diagram of the overall structure of a VOCs exhaust gas treatment system of the present invention including a waste heat recovery device.

Figure 2 is a schematic diagram of the basic structure of a VOCs exhaust gas treatment system of the present invention.

In the figure, 1-VOCs exhaust gas source, 2-circulation pipeline, 3-circulation fan, 4-diversion valve, 5-exhaust gas treatment equipment, 6-intake device, 8-exhaust pipeline, 9-exhaust device, 10- Waste heat recovery device, 11-air quality control device, 12-explosion-proof device, 13-central information processing control device, 21-return air circulation pipe, 23-supply air circulation pipe, 41-first branch valve, 43-second branch Valve, 71- air quality detection device, 101- first inlet of waste heat recovery device, 103- second inlet of waste heat recovery device, 105- first outlet of waste heat recovery device, 107- second outlet of waste heat recovery device, 411 -The inlet of the first diverter valve, 413-the first outlet of the first diverter valve, 415-the second outlet of the first diverter valve, 431-the inlet of the second diverter valve, 433-the first outlet of the second diverter valve, 435-The second outlet of the second diverter valve.

detailed description

The specific embodiments of the present invention will be further described below in conjunction with the drawings. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

As shown in Figure 1 and Figure 2, the present invention provides a VOCs exhaust gas treatment system, which is composed of two subsystems, respectively, a circulation system and an efflux system. The circulation system is connected to the efflux system: the circulation The system includes an exhaust gas source 1, a supply air circulation pipe 23 and a return air circulation pipe 21 consisting of a circulating pipe 2, a circulating fan 3, a first split valve 41, an air intake device 6, an air quality detection device 71 and a central information processing control device 13 , The circulating fan 3 is arranged in the supply air circulation pipe 23 and the return air circulation pipe 21, the supply air circulation pipe 23 and the return air circulation pipe 21 are connected to the exhaust gas source 1, and the air quality detection device 71 is arranged in the circulation away from the exhaust gas source 1. The external exhaust system includes an external exhaust pipe 8, VOCs exhaust gas treatment equipment 5 and an exhaust device 9. The inlet of the external exhaust pipe 8 is connected to the air circulation pipe 23 through the first branch valve 41, and the external exhaust pipe 8 is provided with The exhaust device 9 is connected to the exhaust gas treatment equipment 5, and the central information processing control device 13 is electrically connected to the air quality detection device 71, the first shunt valve 41 and the exhaust gas treatment equipment 5.

The inlet 431 of the second split valve is connected to the air intake device 6, the first outlet 433 of the second split valve is connected to the air quality detection device 71, and the second outlet 435 of the second split valve is connected to the waste heat recovery device 10 and the waste heat recovery device 10. There are two inlets and two outlets. The first inlet 101 of the waste heat recovery device is connected to the outlet of the exhaust gas treatment equipment 5, the second inlet 103 of the waste heat recovery device is connected to the second outlet 435 of the second split valve, and the second outlet of the waste heat recovery device One outlet 105 is connected to the exhaust device 9, and the second outlet 107 of the waste heat recovery device is connected to the air quality detection device 71.

The exhaust device 9 is equipped with a temperature detection device. When the exhaust temperature reaches or exceeds the set temperature, the central information processing control device 13 adjusts the second split valve 43 to allow more circulating gas to enter the waste heat recovery device 10, thereby reducing the exhaust气温度。 Air temperature.

The air quality adjusting device 11 can be added to the air circulation pipe 23 of the circulation system, one end of which is connected to the air quality detecting device 71, the other end of which is connected to the first outlet 433 of the second shunt valve, and the explosion-proof device 12 is arranged in the first On the external discharge pipe 8 between the shunt valve 41 and the exhaust gas treatment equipment 5.

When the air quality detection device 71 detects that the VOCs exhaust gas concentration does not reach an excessive level, the central information processing control device 13 controls the first shunt valve 41 so that the gas is in an internal circulation state and does not enter the RCO exhaust gas treatment equipment 5.

When the air quality detection device 71 detects that the VOCs exhaust gas concentration reaches a preset level, the central information processing control device 13 controls the first shunt valve 41 to control the volume percentage of exhaust gas entering the external exhaust system within the range of 5%-50%. The gas enters the RTO or RCO waste gas treatment equipment 5 for treatment, and is discharged into the atmosphere, and the remaining 50%-95% of the waste gas flows into the waste gas source again through the circulation system. At the same time, the central information processing control device 13 controls the air intake device 6 to add fresh air to the internal circulation pipe to dilute the VOCs exhaust gas.

During the operation of the entire system, the VOCs exhaust gas source continuously produces VOCs exhaust gas, and the air intake device 6 continuously adds fresh air. Through the adjustment of the first diverter valve 41, part of the exhaust gas is continuously diverted to the VOCs treatment equipment for treatment, and finally discharged into the atmosphere. In the end, the VOCs exhaust gas concentration in the circulation pipeline will be dynamically stabilized within the set concentration range.

Take the gravure printing enterprise as an example, and further explain it in conjunction with Figure 1. Refer to the situation that the gravure printing company has one or more printing presses, laminating machines or coating machines, and each of the above equipment has one or more stations that generate VOCs exhaust gas, such a station is equivalent to 1 VOCs Waste gas source 1.

Wherein, each of the above-mentioned stations has a corresponding air inlet connecting the air supply circulation duct 23 and the exhaust air outlet of the return air circulation duct 21. In actual production, in order to increase the volatilization speed of organic solvents in printed products and reduce the solvent content of the final product, the industry now generally adopts measures to increase the inlet air temperature, that is, heating the inlet air. The air volume required for each station is about: 1000～5000m ³ /h. Each time the air passes, the VOCS exhaust gas concentration increases by about 50～2000mg/m ³ , and the heating power is about: 10KW～50KW. This is a typical large air volume. Low concentration, high energy consumption VOCs exhaust gas source.

Referring to Figure 1, the present invention connects the various stations of each of the above-mentioned equipment in series or parallel with air ducts to form a large VOCs exhaust gas source assembly, and then connect it to Figure 1 Shown in the system.

Among them, the VOCs waste gas treatment equipment may be a set of RTO or RCO waste gas treatment equipment 5, which burns the VOCs waste gas discharged to the outside. The heat generated by the combustion passes through the waste heat recovery device 10 and is used to heat the gas in the circulation system for normal production. Correspondingly, the circulating pipeline needs to be insulated.

If a fan is installed on the printing machine, laminating machine or coating machine, the number of circulating fans 3 in the circulation system can be increased or reduced, depending on the fan's ability to push the circulating gas.

After the RTO or RCO waste gas treatment equipment 5 processes up to the standard gas, the temperature will reach 400°C to 1200°C. Before being discharged into the atmosphere, these gases pass through the waste heat recovery device 10 to exchange heat into the circulating gas in the circulation system for production, which has the effect of reducing waste, energy saving, and emission reduction.

Among them, during the continuous operation of the system, through the first split valve 41 and the RTO or RCO exhaust gas treatment equipment 5, part of the VOCs exhaust gas in the system is continuously processed and discharged into the atmosphere, and the air intake device continuously supplements fresh air to the pipeline , Each station on each equipment continuously produces new VOCs exhaust gas, so as to maintain the VOCs exhaust gas concentration in the circulation system stable within the set range.

To ensure safety, an explosion-proof device 12 needs to be installed between the first shunt valve and the RTO or RCO waste gas treatment equipment 5. In order to coordinate the circulation fan, the first shunt valve 41, the second shunt valve 43, the RTO or RCO exhaust gas treatment equipment 5, the air intake device 6, and the joint action of the fan equipment, a central information processing control device 13 needs to be installed to achieve the system Runs efficiently and energy-savingly.

The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions and modifications to these embodiments still fall within the protection scope of the present invention.

Claims (6)

A VOCS exhaust gas treatment system is composed of two sub-systems respectively a circulation system and an external exhaust system. The circulation system is connected to the external exhaust system, and is characterized in that: the circulation system includes an exhaust gas source and an air supply circulation Pipes, return air circulation pipes, circulating fans, first split valves, air intake devices, air quality detection devices and central information processing and control devices, the circulating fans are arranged in the air supply circulation pipes and the return air circulation pipes , The air supply circulation pipe and the return air circulation pipe are connected to the exhaust gas source, the air quality detection device is arranged at the end of the circulating fan away from the exhaust gas source, the external exhaust system includes an external exhaust pipe, and VOCS exhaust gas Processing equipment and exhaust device, the inlet of the outer exhaust pipe is connected to the circulation pipe through the first shunt valve, and the outer exhaust pipe is provided with an exhaust device and is connected with the VOCS exhaust gas processing equipment, so The central information processing control device is electrically connected to the air quality detection device, the first shunt valve, the circulating fan, the exhaust device and the VOCS exhaust gas processing equipment. The VOCS exhaust gas treatment system according to claim 1, characterized in that: 50%-95% of the exhaust gas flowing out of the VOCS exhaust gas source flows into the exhaust gas source again through the circulation system; 5%-50% of the exhaust gas flowing out of the VOCS exhaust gas source, After being processed by the efflux system, it is discharged into the atmosphere. The VOCS exhaust gas treatment system according to claim 1, wherein the VOCS exhaust gas treatment equipment is one or a combination of an RTO combustion device, an RCO combustion device, an activated carbon adsorption device, a condensation recovery device, and a plasma decomposition device. The VOCS exhaust gas treatment system according to claim 3, characterized in that: when the VOCS exhaust gas source needs to use hot air to dry during the working process, the VOCS exhaust gas treatment equipment of the system preferably uses a combustion device such as RTO or RCO, and each The section pipeline is the pipeline for thermal insulation treatment. The VOCS exhaust gas treatment system according to claim 4, wherein the circulation system further comprises a second split valve and a waste heat recovery device, the inlet of the second split valve is connected to the intake device, and the first outlet of the second split valve is connected to the The second outlet of the air quality control device is connected to the waste heat recovery device, and the waste heat recovery device is provided with two inlets and two outlets. The first inlet of the waste heat recovery device is connected to the outlet of the exhaust gas treatment equipment, and the second outlet of the waste heat recovery device The two inlets are connected to the second outlet of the second shunt valve, the first outlet of the waste heat recovery device is connected to an exhaust device, and the second outlet of the waste heat recovery device is connected to an air quality control device. The VOCS exhaust gas treatment system according to claim 5, further comprising an air quality adjustment device and an explosion-proof device, one end of the air quality adjustment device is connected to the air quality detection device, and the other end is connected to the second The first outlet of the shunt valve, the explosion-proof device is arranged on the pipeline between the first shunt valve and the VOCS exhaust gas treatment equipment.

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