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- Title
VOCs 燃烧催化剂耐硫性新进展.
- Authors
吴冬霞; 程行; 胡江亮; 侯建材; 常丽萍; 王建成; 鲍卫仁
- Abstract
Volatile organic compounds (VOCs) are important precursor of fine particulate matter (PM2.5 ) and O3 compound pollutants. VOCs pollution control has been listed as one of the important tasks in Chinese "13th Five Year Plan" environmental protection management. The "14th Five Year Plan" fuuther pointed out that it is necessary to strengthen the management of urban air quality, promote the collaborative control of PM2.5 and O3, and accelerate the comprehensive treatment of volatile organic compounds emissions. Among various VOCs treatment technologies, catalytic combustion is the most effective method for VOCs treatment because of its wide range in the treatment concentration and no secondary pollution. However, there are usually a certain amount of sulfur compounds in the organic waste gas from coal chemical industry, coking plants, petroleum refineries and other industrial sources in the practical application process, which can interact with the catalyst to cause sulfur poisoning of the catalyst. Therefore, it is of great significance to control mid design the catalyst and improve the sulfur tolerance of the catalyst for the treatment of VOCs. By analyzing the mechanism about the catalytic combustion of VOCs the important role of active oxygen in the process of catalytic combustion of VOCs was pointed out. The mechanism about sulfur poisoning of the catalyst was analyzed. The main causes about sulfur poisoning of the catalyst were given. According to the combustion mechanism and sulfur poisoning mechanism of the catalyst, four ways to improve the sulfur tolerance of the catalyst were summarized. Meanwhile, the characterization techniques of sulfur tolerance catalyst were given. On the basis of the global research status and technical level, the difficulties in the synthesis of sulfur tolerant catalysts and the future research focus were pointed out. There are three reaction mechanisms for the catalytic combustion of VOCs. The type of active oxygen is related to the reaction mechanism, and the type and concentration of active oxygen are closely related to the sulfur resistance of the catalyst. Therefore, it is of great significance to determine the catalytic reaction mechanism, analyze the type of active oxygen species and improve the oxygen reduction ability of the catalyst for the sulfur resistance of the catalyst. According to the sulfur poisoning mechanism of the catalyst, sulfides competed with VOCs to occupy the a adsorption active sites, the active sites arc reduced, and the catalyst is inactivated; sulfur compounds react with catalyst components to form sulfate, which blocks catalyst channels and covers catalyst active sites, resulting in sulfur poisoning of the catalyst. By introducing promoters, the acid and, alkalinity of the catalyst can be adjusted, and the weak acidity of the catalyst can weaken the adsorption of sulfide. By introducing promoters and adding sulfating supports, the interaction between active components and sulfide can he weakened, and the acidification of active components can he weakened. The coexistence of water and sulfide in the catalytic combustion system can prevent the deposition of sulfate radical on the catalyst surface. The wet sulfate catalyst containing a huge number of surface hydroxyl groups has higher surface acidity, thus promoting catalytic activity . The sulfur resistance of the catalyst can be improved by improving the oxidation-reduction performance of catalyst, inhibiting the adsorption of sulfide, weakening the interaction between sulfide and catalysts and controlling the composition of raw gas.
- Subjects
ORGANOSULFUR compounds; FIVE year plans; SULFUR compounds; AIR quality management; CATALYTIC activity; COKE (Coal product); EMISSION inventories; CATALYST poisoning
- Publication
Clean Coal Technology, 2022, Vol 28, Issue 2, p67
- ISSN
1006-6772
- Publication type
Article
- DOI
10.13226/j.issn.1006-6772.VOCs21070301