Working principle and product characteristics of catalytic combustion

Catalytic combustion is a method that uses catalysts to oxidize and decompose combustible substances in the exhaust gas that needs to be treated at a lower temperature. In the entire catalytic purification process, the role of the catalyst is to reduce the activation energy of chemical reactions, thereby making the reaction conditions more favorable for controllable purposes. With the help of catalysts, exhaust gas can be effectively ignited at lower temperatures, resulting in flameless combustion. Then, it is oxidized and decomposed into harmless carbon dioxide and water, releasing a large amount of heat energy. This can achieve the removal of harmful substances from exhaust gas and purify it.

This processing method requires less auxiliary fuel, has lower energy consumption, and requires a smaller volume for processing equipment and facilities. Easy to operate, safe, and highly efficient in purification, it is very suitable for applications in industries such as chemical, painting, insulation materials, and coating production. The treatment temperature of catalytic combustion is generally determined by the exhaust gas, and the treatment temperature varies depending on the exhaust gas. The temperature is generally around 250 ℃ -500 ℃. The normal process for handling involves three steps: adsorption, desorption, and combustion.

Simply put, it's all about utilizingactivated charcoalThe adsorption principle involves first allowing activated carbon to adsorb organic waste gas, and then allowing the activated carbon that has adsorbed the waste gas to desorb it through a high-temperature airflow. In this way, activated carbon can be repeatedly circulated for adsorption and desorption. The desorbed exhaust gas will be concentrated and then enter the catalytic combustion chamber for decomposition and release. After catalytic combustion treatment, a portion of the exhaust gas meets the standard and is discharged into the atmosphere, while the other portion is returned to the adsorption bed for activated carbon desorption. This can better provide heat for adsorption desorption catalysis and is energy-saving, environmentally friendly, and efficient.

Catalytic combustion equipmentprinciple

Catalytic combustion equipment, also known as combustion devices, is a type of equipment used to treat exhaust gases. The equipment mainly consists of heat exchange device, combustion chamber, catalytic reaction equipment, heat recovery system, and flue gas emission equipment. This device requires the use of catalysts in order to achieve flameless combustion of organic waste gas at lower ignition temperatures. Other working principles and processes can be divided into the following three types.

1. Preheating type

This is a relatively basic process technology, as catalysts have a main principle that when the temperature of organic waste gas is below 100 ℃ and the concentration is low, the heat is generally not self-sufficient. Therefore, it is necessary to heat it up in the preheating chamber before entering the reactor. The commonly used preheating methods are gas or electric heating, which can raise the temperature of the exhaust gas to the ignition temperature required for catalytic reaction, thereby achieving the purpose of combustion, oxidation and decomposition. The gas after combustion and oxidation exchanges heat with the untreated exhaust gas in the heat exchanger, thereby recovering some of the heat.

2. Self thermal equilibrium

The temperature of organic waste gas is relatively high and the content of organic matter is also relatively high. Under normal circumstances, it is only necessary to use an electric heater in the combustion chamber of the catalytic combustion equipment to start combustion, and then recover the heat generated by partially purified gas through an exchanger. The advantage of this is that it can maintain thermal balance under normal operation without the need for additional heat supplementation.

3. Adsorption

This method is mainly used to treat organic waste gases with high flow rate, low concentration, and low temperature. When catalytic combustion is used to treat this type of exhaust gas, a large amount of fuel is consumed. From the perspective of fuel conservation, adsorption can be used to adsorb the exhaust gas onto adsorbents, such as the well-known activated carbon. After adsorption, it is concentrated and then purged with hot air to desorb into a gas with a higher concentration before combustion and decomposition. This method does not require additional heat supply and can operate normally.

feature

1. Low ignition temperature, fast reaction speed, and energy-saving. In the process of catalyst combustion, the role of the catalyst is to reduce the activation energy of VOC and oxygen molecules, and change the reaction route. Compared with thermal combustion, catalytic combustion has the advantages of low ignition temperature and fast reaction rate. Refer to the comparison of catalyst combustion performance and thermal combustion performance. Catalyst combustion has a lower ignition temperature, saving the consumption of auxiliary energy, and in some cases does not require external heating.

2. High processing efficiency, minimal secondary pollutants, and greenhouse gas emissions. The efficiency of catalytic combustion purification of Voc is generally above 95%, and the products after decomposition and oxidation are mainly CO2 and H2O. Due to the lower combustion temperature of the catalyst, the generation of NOx is significantly reduced [3-5]. The proportion of CO2 emissions from auxiliary fuel consumption is relatively large, which reduces the consumption of auxiliary energy and significantly lowers the CO2 emissions of greenhouse gases.

3. Widely applicable. Catalytic combustion can treat almost all hydrocarbon organic waste gases and odorous gases, as well as VOCs that are widely applicable for treatment. For VOCs with low concentration, high flow rate, multiple components, and non recyclability, the most economical method for catalytic combustion is to use it.

4. High degree of automation and low energy consumption. And it is relatively easy to operate, with automatic alarm when encountering faults, low energy consumption, durable anti-corrosion, and longer service life of the equipment.

5. The operating cost is relatively low. If the concentration of organic waste gas reaches 1000mg/m3 or more, the heating chamber in the purification equipment does not require auxiliary heating, which can effectively save the production cost during heating.

scope

Catalytic combustion equipment is widely used in industries such as wire processing, machinery, motors, chemicals, equipment, automobiles, engines, plastics, electrical appliances, petroleum, chemical, printing and dyeing due to its advantages of simple structure, high purification efficiency, energy saving, and secondary pollution. Other industriesOrganic waste gas treatmentSuch as benzene, ethanol, ethyl acetate, triphenyl (benzene, toluene, xylene) and * * in the paint industry, isopropanol in the printing industry, ethyl acetate, toluene, dichloromethane in the electronics industry, and adsorption recovery of trichloroethane. In addition, it can also process hydrocarbons (aromatic hydrocarbons, alkanes, alkenes), oxygen-containing organic compounds (alcohols, ketones, organic acids, etc.), nitrogen-containing organic compounds, sulfur, halogens, phosphorus containing organic compounds, etc.