Energy & Fuels, Vol.26, No.3, 1520-1530, 2012
Catalyst Screening for the Production of Furfural from Corncob Pyrolysis
Acidic pyrolysis of comcobs is carried out at 800 K in a packed-bed reactor using several catalysts (H2SO4, H3PO4, H3BO3, (NH4)(2)SO4, ZnCl2, NiCl2, MgCl2, and Fe-2(SO4)(3)). In all cases, the yields of char, water, and some condensable organic compounds (acetic acid, levoglucosenone, 1,4:3,6-dyanhydro-alpha-n-glucopyranose, and furfural) are significantly increased at the expense of the phenolic and carbohydrate products typical of uncatalyzed pyrolysis. The maximum yields of furfural (FF) are around 5-6% for the H2SO4, Fe-2(SO4)(3),and ZnCl2 treatments, with potential further increase, following secondary degradation of the main anhydrosugars, up to 8.5% (H2SO4, Fe-2(SO4)(3)) or 6.5% (ZnCl2). Additional experiments made with a wide range of Fe-2(SO4)(3) concentrations, and a comparison with previous results obtained for H2SO4 and ZnCl2 treatments indicate that the best performances are shown by the first catalyst with potential FF yields up to 10%. Moreover, at low concentrations, it also highly promotes the formation of levoglucosan, 5-methylfurfural, 5-hydroxymethylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, and 3-hyclroxy-2-penteno-1,5-lactone, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one.