Catalyst Evaluation for Catalytic Biomass Pyrolysis

Abstract

Commercial catalysts, including zeolites (HZSM-5), fluid catalytic cracking (FCC) catalysts, transition metal catalysts (Fe/Cr), and aluminas, were successfully evaluated in a fixed bed catalytic reactor using a mixture of model compounds to simulate biomass flash pyrolysis vapors. Successful criteria including the stability index (SI), the water generation (WG), and the loss of organics (LO) were introduced to monitor the effect of catalysts and ascertain major changes in the obtained liquid product composition. SI being a measure of the effective carbonyls reduction after catalytic cracking reached 100% in the case of HZSM-5 catalysts, leading to the selective production of aromatic hydrocarbons. Transition metal catalysts (Fe/Cr) lead to the selective production of phenol and light phenolics. Comparable trends were obtained using solid biomass in the catalytic fixed bed reactor.

Hydrogen production from pine and poplar bio-oils by catalytic steam reforming. Influence of the bio-oil composition on the process

“…This result is in concordance with the work of Samolada et. al [39], where higher conversions of furfural were obtained during the catalytic pyrolysis of a furfural/organic mixture than when this compound was treated alone. Table 10 shows the CC coke and the amount of C deposited on the catalyst surface (mg C/g catalyst g organic reacted) for the experiments with model compounds.…”

“…On the other hand, the reactivity of acetic acid could be different when reforming alone than as part of an organic mixture. Interactions between chemicals in the aqueous fractions might take place during the reforming process, resulting in the formation of different compounds with a different behaviour in the process [39]. In the case of furfural, a lower overall 2 h global conversion was obtained during the reforming of the model compound alone than in the aqueous fraction.…”

Catalytic effect of metal nitrate salts during pyrolysis of impregnated biomass

“…Most of the time, the catalysts are supported on alumino-silicate structures, like zeolites [2]. Catalysts can be mixed with the biomass within the reactor [3], or placed in a fixed-bed at the outlet of the pyrolysis reactor [4], or used as a bed material in fluidised bed reactors [5]. Pyrolysis of metal salt impregnated biomass has also been considered.…”

Rheological Characterization of Bio-Oils from Pilot Scale Microwave Assisted Pyrolysis

“…Because of the high oxygen (40-50 wt %) and water content (15-30 wt %) and the low H/C ratios, bio-oils cannot be used as transportation fuels directly without prior upgrading. As mentioned earlier additional obstacles are the limited stability of the bio-oils under storage conditions due to the presence of unsaturated compounds and their minor miscibility with conventional liquid fuels (Samolada et al, 2000). Catalytic biomass pyrolysis is a promising approach due to the elimination of costly condensation and re-evaporation procedures prior to bio-oil upgrading (Samolada et al, 2000;Lu et al, 2009a).…”

“…As mentioned earlier additional obstacles are the limited stability of the bio-oils under storage conditions due to the presence of unsaturated compounds and their minor miscibility with conventional liquid fuels (Samolada et al, 2000). Catalytic biomass pyrolysis is a promising approach due to the elimination of costly condensation and re-evaporation procedures prior to bio-oil upgrading (Samolada et al, 2000;Lu et al, 2009a). Several studies have indicated that the viscosity of bio-oil depends on the type of feedstocks, type of pyrolyzer, and pyrolysis conditions.…”