Study On The Effect Of Red Mud And Its Component Oxides On The Bio-Oil Of Corn Straw Catalytic Pyrolysis

The catalytic pyrolysis technology of biomass has become the focus due to oriented enrichment of bio-oil special components.Red mud,as a kind of solid waste discharged from alumina industry,is of great economic value for catalytic pyrolysis.To explore catalytic effects of red mud to bio-oil components（BOC）,calcined temperature,adding ratio,oxide components（Al₂O₃,Fe₂O₃,Ca O,Si O₂ and TiO₂）and their first-order interaction were studied in this paper.The results shown that:Calcined temperature of red mud is important factor for BOC.The influences on BOC catalyzed by RM（red mud only dried）,600RM-800RM（red mud calcined at 600℃,700℃ and800℃,especially）are similar.Ketonization reactions improve obviously with the increasing of the amount of red mud,in which the relative content of acids decreased and ketones increase gradually.In addition,it was high selectivity for furan compounds and the formation of aldehydes were inhibited.For alcohols,the catalytic effects were different.The contents of alcohols were lower for RM and 600RM,but increased for 700RM and 800RM.For 900RM and 1000RM,the catalytic effects were same,namely alcohols and ketones were increased while aldehydes were decreased.The effects of five typical oxides of red mud on BOC were different.The alcohols contents were increased for Al₂O₃.The catalysis of Fe₂O₃inhibited the formation reaction of benzofurans and aldehydes.Ca O could help to promote the formation of benzofurans,ketones and phenols,and inhibit the formation of acids and aldehydes.TiO₂ had no obvious catalytic effect.Si O₂ made the content of phenylpropylfurans decline.The effects of the first-order interaction among oxide components were significant for BOC according to visual and variance analysis.The highest relative content of 2,3-dihydrobenzofuran was obtained by adding Fe₂O₃,Ca O,TiO₂ and Si O₂,in which the interaction of Fe₂O₃ and Ca O had highly significant impact,and the interaction of Si O₂ and Ca O enhanced catalysis of Ca O.The highest relative content of alcohols was obtained by adding Fe₂O₃,Ca O and TiO₂.The interaction between any two oxides had highly significant impact,and the interaction of Fe₂O₃ and Ca O was most significant.Adding Al₂O₃,Ca O and Si O₂was helped to obtain the highest relative content of phenols.The interaction between Si O₂and other oxides had highly significant impact for lignin pyrolysis.The highest relative content of furans was obtained by adding Fe₂O₃,and the interaction between Fe₂O₃ and other oxides decreased content of furans.The highest relative content of ketones was obtained by adding Ca O,and the content was declined by interaction between Fe₂O₃and Ca O.There were no significant effects between Ca O and other oxides.The lowest relative acids content was obtained by adding Ca O and Si O_2.The interaction reduced formation of acids although Si O₂had no significant effect separately.The highest relative content of aldehydes was obtained by adding Al₂O₃,TiO₂ and Si O₂.The role of interaction between TiO₂ and Al₂O₃was more significant than that of single one.The interaction between Al₂O₃ and Si O₂ had help to formation of aldehydes although Si O₂had no significant effect.To sum up,the red mud calcined at different temperatures has influence on the corn straw catalytic pyrolysis.The catalytic mechanism is mainly affected by the oxidesand their interaction.This study provides a large number of data support for red mud catalytic pyrolysis,which has help to improve quantify of red mud and accelerate the research of biomass catalytic pyrolysis directional production of high value-added chemicals.