Development And Performance Study Of Catalyst For Catalytic Oxidation Of Aromatic Solvent Oil At Low Temperature

Volatile organic compounds（VOCs）pose a great threat to natural environment and human health,and it is urgent to strengthen the prevention and control of VOCs pollution comprehensively.Catalytic combustion technology is an economically efficient VOC treatment technology,the key of which is to achieve low-temperature flameless combustion of VOCs through catalysts.Aromatic volatile organic compounds have characteristics such as being difficult to biodegrade,carcinogenic,teratogenic,mutagenic,and long-term accumulation,making them a current research hotspot.Based on this,two catalysts were designed according to the synergistic effect of the acidity and redox properties of the catalysts,using two different aromatic solvent oils as VOC model gases to investigate their activity in catalytic combustion of aromatic solvent oils.The changes in the activity and product selectivity of two catalysts under different conditions of metal loading were studied in order to provide theoretical guidance for the development of high-performance catalysts.This paper carried out the following work around the above content:1.Co-ZiF-67 metal organic framework materials modified with different loading amounts of Ni metal.Firstly,Co-ZiF-67 metal organic framework materials were prepared,and then three different Ni@ZiF-67 catalysts with different Ni metal content were prepared.Two types of aromatic solvent oil were used as the model for catalytic oxidation reaction to explore their catalytic oxidation activity in the temperature range of 180～350℃.The results showed that the four catalysts had different catalytic effects,and the 40Ni@ZiF-67 catalyst had the best catalytic activity.Analysis of the byproduct CO produced during the reaction process showed that as the temperature increased,the production of CO also increased.Among the four catalysts,the 40Ni@ZiF-67 catalyst had the least amount of CO produced.The catalyst was subjected to a 24-hour stability test,and the results showed that the catalytic activity of the catalyst for two types of aromatic solvent oils could maintain above 90%at 320℃,and no deactivation was found.BET,XRD,TEM,SEM,Raman and other characterization techniques were used to analyze the structural changes of catalysts with different Ni loading amounts.Combined with the characterization data of the catalyst and the analysis results of the reaction products,the amount of Ni added is the main factor determining the morphology and structure,and proper addition is conducive to the formation of strong interaction between NiO and Co₃O₄,promoting the degradation of aromatic solvent oils.2.Non-precious metal oxide molecular sieve catalysts with different Ce/Cr ratios loaded on HZSM-5 were prepared by impregnation method.Two aromatic solvent oils were used as the model for catalytic oxidation reaction,and the catalytic oxidation activity was explored in the temperature range of 180～350℃.The structural changes of catalysts with different Ce/Cr ratios were analyzed by BET,XRD,TEM,SEM,IR and other characterization techniques.The research results show that with the increase of Ce loading,the redox ability of the catalyst gradually enhances.When the reaction temperature reaches 350℃,the catalytic activity of Ce_0.7Cr_0.3/HZSM-5 catalyst is the highest,and the conversion rate of 100^#and 150^#aromatic solvent oil can reach 96.66%and 96%,respectively.The yield of byproduct CO gradually decreases with the increase of Ce/Cr ratio,indicating that the addition of Ce is beneficial to reducing the yield of byproducts.The test results show that the supported metal makes HZSM-5have more defect sites,increases the specific surface area and improves its catalytic ability.Stability testing at 320℃for 24 hours was conducted on Ce_0.7Cr_0.3/HZSM-5catalyst,and no significant decline in catalytic activity was observed.These results indicate that this catalyst has good catalytic performance and is suitable for industrial catalytic treatment of VOCs.