A study on the deoxidation effect of different acidic zeolites during the co-pyrolysis of aged municipal solid waste and corn stalk

摘要

The low calorific value of bio-oil resulting from the high oxygen content limited the application of pyrolysis bio-oil as fuel. In this work, the synergistic deoxidation effect between aged municipal solid waste and corn stalk was applied to reduce the oxygenated compounds in bio-oil. The deoxidation effect of different acidic zeolites was investigated to further improve the bio-oil quality. The oxygenated organics produced from the co-pyrolysis of aged municipal solid waste and corn stalk without catalysts were reduced as compared with the theoretical value, ranging from -1.2 % to -14.6 %. Correspondingly, the hydrocarbons in the co-pyrolysis products increased. The olefins could increase by up to 28.8 % compared with the theoretical value. The addition of an acidic catalyst increased the conversion rate of AM, and the residual mass was significantly reduced. When the Brunsted acidity of the catalyst was stronger, the reactions of olefins occurring during catalyst fast pyrolysis were cyclization and aromatization, which could produce up to 57.86 % of aromatic hydrocarbons. When the catalyst had more Lewis acid sites, a Diels-Alder reaction of C6-C10 olefins with furans was more likely to occur. When the Brunsted acid sites were insufficient to promote the subsequent deoxygenation reaction, the aromatics yield dropped to 0.22 % similar to 3.38 %. In addition, long chain olefins were cracked into small molecule olefins with the addition of zeolites. After adding ZSM-5, olefins with 3-5 carbon atoms accounted for 44.23 %.