Catalytic combustion technology as one of the VOCs waste gas treatment processes, because of its high purification rate, low combustion temperature (< 350 ° C), combustion without open flame, there will be no secondary pollutants such as NOx generation, safety, energy saving and environmental protection and other characteristics, in the environmental protection market application has a good development prospects. As the key technical link of catalytic combustion system, catalyst synthesis technology and application rules are particularly important.
1. Principle of catalytic combustion reaction
The principle of catalytic combustion reaction is that the organic waste gas is completely oxidized and decomposed under the action of the catalyst at a lower temperature to achieve the purpose of purifying the gas. Catalytic combustion is a typical gas-solid phase catalytic reaction, and its principle is that reactive oxygen species participate in deep oxidation.
In the catalytic combustion process, the function of the catalyst is to reduce the activation energy of the reaction, while the reactant molecules are enriched on the catalyst surface to increase the reaction rate. With the help of a catalyst, the organic waste gas can burn flameless at a lower ignition temperature and release a large amount of heat while oxidizing and decomposing into CO2 and H2O.
3. Role and influence of VOCs catalyst in catalytic combustion system
Usually, the self-combustion temperature of VOCs is high, and the activation energy of VOCs combustion can be reduced through the activation of the catalyst, so as to reduce the ignition temperature, reduce energy consumption and save costs.
In addition, the combustion temperature of the general (no catalyst exists) will be above 600 ° C, and such combustion will produce nitrogen oxides, which are often said to be NOx, which is also a pollutant to be strictly controlled. Catalytic combustion is combustion without an open flame, generally below 350 ° C, there will be no NOx generation, so it is safer and more environmentally friendly.
4. What is airspeed? What are the factors that affect airspeed
In the VOCs catalytic combustion system, the reaction space speed usually refers to the volume space speed (GHSV), reflecting the processing capacity of the catalyst: the reaction space speed refers to the amount of gas processed per unit time per unit volume of the catalyst under specified conditions, the unit is m³/(m³ catalyst •h), which can be simplified as h-1. For example, the product is marked with space speed 30000h-1: it means that each cubic catalyst can handle 30000m³ exhaust gas per hour. The air speed reflects the VOCs processing capability of the catalyst, so it is closely related to the performance of the catalyst.
5. The relationship between precious metal load and airspeed, is the higher the precious metal content the better?
The performance of precious metal catalyst is related to the content of precious metal, particle size and dispersion. Ideally, the precious metal is highly dispersed, and the precious metal is present on the carrier in very small particles (several nanometers) at this time, and the precious metal is utilized to the greatest extent, and the processing capacity of the catalyst is positively correlated with the precious metal content. However, when the content of precious metals is high to a certain extent, the metal particles are easy to gather and grow into larger particles, the contact surface of precious metals and VOCs decreases, and most of the precious metals are wrapped in the interior, at this time, increasing the content of precious metals is not conducive to the improvement of catalyst activity.
Post time: Aug-03-2023