Adsorption and catalytic combustion exhaust gas treatment equipment

1) Technical principles

New type of adsorption -catalytic combustionIn the process of catalytic combustion, new types of activated carbon (mostly honeycomb shaped activated carbon or fiber carbon) are used to adsorb and concentrate low concentration organic waste gas. After the adsorption is close to saturation, hot air is introduced to heat the activated carbon, causing the organic waste gas to desorb and enter the catalytic combustion bed for flameless combustion purification treatment. The hot gas is circulated in the system or a secondary heat exchanger is added for heat recovery. This method concentrates low concentration organic waste gas into high concentration organic waste gas through activated carbon and purifies it through a combustion bed. This method absorbs the advantages of adsorption and catalytic combustion methods, overcomes the disadvantages of using them separately, and solves the problems of treating low concentration and high air volume organic waste gas. It is currently a mature and practical method for treating organic waste gas in China.

2) Equipment structure

Catalytic combustion method: It uses a catalyst as an intermediate to convert organic gases into harmless water and carbon dioxide gases at lower temperatures, namely:

The organic gas source in the drying chamber is sent to the purification device through the induced draft fan. Firstly, it passes through the dust removal flame arrester system, and then enters the heating chamber. Through the heating device, the gas reaches the combustion reaction temperature. Then, through the catalytic bed, the organic gas is decomposed into carbon dioxide and water, and enters the heat exchanger for heat exchange with low-temperature gas, raising the temperature of the incoming gas to the reaction temperature. If the reaction temperature cannot be reached, the heating system can compensate for heating through the automatic control system, allowing it to burn completely, saving energy. The effective removal rate of exhaust gas reaches over 97%, which meets the national emission standards.

This device consists of a main unit, induced draft fan, and electrical control cabinet. The purification device main unit consists of a heat exchanger, catalytic bed, electric heating element, explosion-proof device of flame arrester, etc. The flame arrester dust collector is located on the intake pipeline, and the explosion-proof device is located on the top of the main unit. The process flow diagram is as follows:

Direct discharge outlet: The exhaust gas source should have a direct discharge pipeline, controlled by valves, and if necessary, the exhaust gas should be directly discharged (such as during the maintenance of the purification device).

Flame arrester: composed of specially designed multi-layer metal mesh, it can prevent flames from passing through and filter out larger particles (pollutants) in the gas. It is one of the devices of this purification device.

Heat exchanger: Plate structure, its function is to use the heat released by catalytic reactions to heat the inlet exhaust gas, improve the utilization rate of heat energy, and reduce heating electricity.

Preheating chamber: The exhaust gas preheated by the burner heating exchanger is heated to increase the inlet temperature to achieve catalytic reaction conditions.

Thermistor: Stainless steel protective tube is used to measure the intake heating temperature and purification temperature.

Catalytic bed: composed of multiple layers of honeycomb catalysts, it is the core of this device.

Explosion proof device: It is a diaphragm pressure relief device. When the equipment operates abnormally, it can be promptly cracked to release pressure and prevent accidents from occurring.

Fan: Adopting a rear induced draft type, this device operates under negative pressure.

Valve: Control and regulate the flow rate of gas.

3) Technical features

a、 The device has advanced design principles, unique materials, stable performance, simple operation, reliability, and no secondary pollution. The equipment has a small footprint and is lightweight. The adsorption bed adopts a drawer type structure, which is easy to load and easy to replace.

b、 Adopting a new type of activated carbon adsorbent material - honey like activated carbon, which has advantages in thermodynamic properties, low resistance, high adsorption rate, etc. compared to granular (rod) form, it is suitable for high air volume use.

c、 The catalytic combustion chamber uses precious metal catalysts with ceramic honeycomb bodies, which have low resistance and can operate normally with a low-pressure fan. It not only consumes less power but also has low noise.

d、 The air volume of the catalytic combustion device is one tenth of the exhaust gas source air volume, and the heating power is maintained for about 1 hour, saving energy.

e、 The activated carbon bed that adsorbs organic waste gas can use the heat generated by catalytic combustion to desorb and regenerate the waste gas. The desorbed gas is then sent to the catalytic combustion chamber for purification without the need for additional energy, resulting in low operating costs and significant energy-saving effects.

f、 An automatic emergency fire sprinkler system is installed inside the activated carbon adsorption bed to ensure the safety of the system.

4) Scope of application

Applied to the treatment of organic waste gases with high air volume and low concentration, it can treat benzene, ketones, alcohols, ethers, alkanes and their mixed organic waste gases. It is mainly used for the purification and treatment of harmful waste gases generated in chemical, mechanical, electronic, electrical, painting, shoemaking, rubber, plastic, printing and various industrial production workshops.