脱碱赤泥催化剂制备及对秸秆催化热解生物油成分的影响

赤泥含有具有催化作用的元素，同时含有一定的孔，可用作催化剂。赤泥的强碱性导致催化剂表面烧结、酸性不足等问题。该研究采用柠檬酸交换钠及焙烧制备了脱碱赤泥催化剂，赤泥的脱碱率达到96%。表征发现脱碱赤泥结构更稳定，硅铝酸盐聚合度降低，Al、Fe、Ti等具有催化作用的元素含量增加、比表面积增加、中强酸酸性位点增多等。用于催化秸秆热解，产物生物油中醛类、酚类、呋喃类变化明显，其中2,3-二氢呋喃含量增加了15.9倍。脱碱赤泥对生物油的产率影响较小，不可冷凝气体、生物炭产率变化明显。推断与脱碱赤泥促进了脱羟和脱羰基反应、葡萄糖脱水重排，强化了脱甲基和脱甲氧基反应有关。

Preparation of dealkalized red mud catalysts and its effect on bio-oil composition of corn straw catalytic pyrolysis

Red mud contains catalytic elements and certain pores, which can be used as catalysts. Its strong alkalinity leads to sintering of the catalyst surface and inadequate acidity. In this study, dealkalized red mud catalysts were prepared by exchange of sodium citrate and calcination. The dealkalization rate reached 96%. Characterization found that the dealkalized red mud was more stable. Polymerization degree of aluminosilicate decreased and the content of Al, Fe, Ti and other catalytic elements increased in dealkalized red mud. The specific surface area and the medium strong acid sites were increased. When the dealkalized red mud was used to catalyze the straw pyrolysis, the aldehydes, phenols and furans in the bio-oil products changed significantly. The content of 2,3-dihydrofuran increased by 15.9 times. The dealkalized red mud had little effect on the production rate of bio-oil, with significant changes in non-condensable gas and biochar production rate. It was inferred that the dealkalized red mud promoted the de-hydroxylation and de-carbonylation reactions,and the dehydration rearrangement of glucose, and strengthened the demethylation and de-methoxy reactions. The research would provide an important reference for the efficient preparation of liquid fuels and fine chemicals by the catalytic pyrolysis of biomass.