Novel porous CaO-MgO promoting γ-Al2O3-catalyzed selective hydrogenation of oleic acid to green bio-gasoline range hydrocarbon fuels with methanol as internal hydrogen source

An efficient and highly selective CaO-MgO promoting γ-Al2O3 decarboxylation catalyst has been fabricated with different CaO to MgO mixed ratios via boll-milling method for the regulation product distribution and production of gasoline-kerosene-diesel range hydrocarbons through catalytic conversion of oleic acid(OA)and methanol under self-hydrogen supply conditions.In addition,influencing factors,reaction mechanism,possible reaction pathway and deactivation mechanism were also probed.The results showed that combination of Ca,Mg and AlOx was very important to boost oleic acid conversion,and synergy between metal and acid active sites via strong metal-support interactions enhanced deoxygenation-cracking activity.Higher alkalinity CaO boosted C-C/C=C bonds cleavage,MgO offered medium Lewis acid sites;BET and mesopore volume suppressed the excessive hydrocracking reactions,improving bio-gasoline yield.Methanol addition provided active hydrogen atoms to enhance bio-gasoline selectivity at the expense of diesel and heavy oil via olefinic cycles and aromatic cycle mechanisms and reduced coke deposition.The maximum hydrocarbon and bio-gasoline yields of 94.53%and 57.59%were achieved at OA/methanol=5:1,pyrolysis/catalytic temperature=450/500°C using 1 g catalyst at a feedstock input rate of 0.1 ml/min