Comparison of catalytic pyrolysis of biomass with MCM-41 and CaO catalysts by using TGA-FTIR analysis

摘要

Pyrolysis of corncob with and without catalyst was investigated using thermogravimetxy analyzer coupled with Fourier transform infrared spectroscopy (TGA-FTIR). The effects of two completely different catalysts, acid catalyst (MCM-41) and base catalyst (CaO), on the formation characteristics and composition of pyrolysis vapor were studied. The results show that these two catalysts give different product distributions. For catalytic run with MCM-41, the molality of carbonyl compounds decreases 10.2%, while that of phenols, hydrocarbons and CH_4 increases 15.32%, 4.29% and 10.16% compared with non-catalytic run, respectively. The increase of phenols exhibits in a wide temperature range from about 295 ℃ to 790 ℃ in the catalytic run with MCM-41 catalyst. However, the use of CaO in pyrolysis of corncob leads to a huge change of product distribution. The molality of acids decreases 75.88%, while the molality of hydrocarbons and CH_4 increases 19.83% and 51.05% compared with non-catalytic run, respectively. CaO is very effective in deacidification and the conversion of acids promotes the formation of hydrocarbons and CH4. Catalytic pyrolysis of corncob with CaO shows two main weight-loss stages. The first stage is from 235 ℃ to 310℃ with a weight loss of 31%. The second stage is from 650 ℃ to 800 ℃ with a weight loss of 21%.