Pretreatment is the first step of the residual gas treatment system of ethylene oxide sterilization workshop, and it is also the premise for ensuring the efficient application of catalytic combustion technology. The main purpose of pretreatment is to remove impurities such as particulate matter, oil, and moisture in the exhaust gas to prevent these impurities from clogging the catalyst and affecting the catalytic effect and stability.
Particle removal: Large particles in the exhaust gas are removed through equipment such as bag dust collectors and cyclone dust collectors to ensure that the exhaust gas entering the catalytic reactor is clean.
Dehumidification and oil removal: Ethylene oxide exhaust gas may contain a certain amount of moisture and oil, which may condense into liquid at low temperatures and block the pores of the catalyst. Therefore, it is necessary to remove moisture and oil from the exhaust gas through condensation, filtration and other methods.
Temperature regulation: Catalytic combustion reactions usually take place within a certain temperature range, and too high or too low temperatures may affect the catalytic effect. Therefore, the exhaust gas also needs to be temperature regulated in the pretreatment stage to ensure that the temperature is appropriate when it enters the reactor.

Catalyst is the core of catalytic combustion technology, and its selection and design are directly related to the catalytic effect and stability. As the carrier of the catalyst, the design of the reactor is also crucial.
Catalyst selection:
Composition: The composition of the catalyst directly affects its catalytic activity, selectivity and stability. Common catalysts include precious metal catalysts (such as platinum, palladium, etc.) and non-precious metal catalysts (such as oxides of copper, manganese, cobalt, etc.). Precious metal catalysts are highly active but expensive; non-precious metal catalysts are less expensive but may be less active. Therefore, it is necessary to comprehensively consider factors such as exhaust gas composition, concentration and temperature to select a suitable catalyst.
Structure: The structure of the catalyst (such as particle size, shape, porosity, etc.) will also affect its catalytic effect. Generally speaking, catalysts with small particles and high porosity have a larger specific surface area, which is conducive to the full contact between exhaust gas and catalyst, thereby improving catalytic efficiency.
Stability: The stability of the catalyst is the key to its long-term application. It is necessary to select a catalyst with strong anti-poisoning ability, high temperature resistance and wear resistance to ensure its stability and reliability in long-term operation.
Reactor design:
Structure: The structure of the reactor should facilitate the full contact and mixing of exhaust gas and catalyst, while ensuring the uniform distribution of exhaust gas in the reactor. Common reactor structures include fixed bed reactor, fluidized bed reactor and trickle bed reactor.
Material: The material of the reactor should have good corrosion resistance and high temperature resistance to ensure its stability and safety in long-term operation.
Operating conditions: The operating conditions of the reactor (such as temperature, pressure, flow rate, etc.) should be optimized according to the characteristics of the catalyst and the composition of the exhaust gas to ensure the best catalytic effect and stability.
After the pretreated exhaust gas is mixed with an appropriate amount of air, it enters the reactor equipped with the catalyst. Under the action of the catalyst, organic pollutants such as ethylene oxide are rapidly oxidized and decomposed at a lower temperature and converted into carbon dioxide and water. This process is the core of catalytic combustion technology and the key to achieving exhaust gas purification.
Oxidation decomposition: Under the action of the catalyst, organic pollutants in the exhaust gas react with oxygen in the air to produce carbon dioxide and water. This reaction is usually carried out at a lower temperature, avoiding equipment damage and safety hazards that may be caused by high temperature operation.
Temperature control: The temperature of the catalytic combustion reaction has an important influence on the catalytic effect. Too high a temperature may cause the catalyst to deactivate or burn, while too low a temperature may affect the catalytic efficiency. Therefore, it is necessary to ensure that the temperature in the reactor is kept within an appropriate range through a temperature control system.
Space velocity and residence time: Space velocity (i.e., the flow rate of exhaust gas through the catalyst) and residence time (i.e., the residence time of exhaust gas in the reactor) are also important factors affecting the catalytic effect. Too high space velocity or too short residence time may lead to incomplete catalysis, while too low space velocity or too long residence time may increase energy consumption and cost. Therefore, it is necessary to reasonably set the space velocity and residence time according to the exhaust gas composition, concentration and characteristics of the catalyst.

Although the concentration of harmful substances in the tail gas after catalytic combustion has been significantly reduced, it still needs further treatment to ensure that the emission standards are met. This usually includes tail gas cooling, dust removal and possible deep purification steps.
Tail gas cooling: After the catalytic combustion reaction, the tail gas temperature is high. It is necessary to use cooling equipment to reduce the tail gas temperature to an appropriate level for subsequent treatment and emission.
Dust removal: Although most of the particulate matter has been removed in the pretreatment stage, new particulate matter may be generated during the catalytic combustion process. Therefore, it is necessary to use dust removal equipment to further remove particulate matter in the tail gas.
Deep purification: For some special occasions, it may be necessary to deeply purify the tail gas to remove possible trace harmful substances. This usually includes chemical absorption, adsorption, membrane separation and other technologies.