Experimental Study on Pyrolysis of Rice Straw Catalyzed by CaO/Al2O3-Phosphate Mixture

Abstract

This paper studied the synergistic effects of CaO or Al 2 O 3 and three potassium phosphates (e.g., KH 2 PO 4 , K 2 HPO 4 •3H 2 O and K 3 PO 4 •3H 2 O) in the rice stalk pyrolysis through pyrolysis-gas chromatography-mass spectrometer (Py-GC/MS) experiments. The results show that after co-catalyzed by CaO/Al 2 O 3 and potassium phosphates, the total contents of phenols, aldehydes, acids, LG from most samples decrease and those of ketones increase compared with those catalyzed by potassium phosphates alone.CaO/Al 2 O 3 and potassium phosphates show synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. and are suitable for the production of ketone-rich bio-oil. Dehydration reactions, etc. are further promoted under the co-catalysis of the two catalysts, and some phenols can be converted to benzene products, etc. The contents of acetic acid can decrease to 0. For 50% K 3 PO 4 .3H 2 O impregnated sample, the yields of furans reduce sharply after CaO addition. For most impregnated samples except 50% K 2 HPO 4 •3H 2 O sample and 30%, 50% K 3 PO 4 .3H 2 O, the contents of total furans and furfural increase after Al 2 O 3 addition.