Characterisation of palm empty fruit bunch (PEFB) and pinewood bio-oils and kinetics of their thermal degradation.

Ultimate and proximate analyses and thermal degradation of bio-oils from pinewood and palm empty fruit bunches (PEFB) were carried out to evaluate the oils' potential for production of fuels for transport, heat and power generation, and of hydrogen via the calculation of performance indicators. The pinewood and PEFB oils indicated good theoretical hydrogen yields of 13.7 and 15.9 wt.% via steam reforming, but their hydrogen to carbon effective ratios were close to zero, and their propensity for fouling and slagging heat exchanger surfaces via combustion was high. Both oils exhibited two phases during mass loss under nitrogen flow at heating rates of 3-9 Kmin(-1), but the kinetics of their thermal degradation from TGA-FTIR analysis indicated different degradation mechanisms that were well reproduced by a nth order reaction model for pinewood and Jander's 3D-diffusion model for PEFB. These findings lead to recommendations on pretreatments prior to the oils' utilisation.

High purity H2 by sorption-enhanced chemical looping reforming of waste cooking oil in a packed bed reactor.

High purity hydrogen (>95%) was produced at 600 degrees C and 1 atm by steam reforming of waste cooking oil at a molar steam to carbon ratio of 4 using chemical looping, a process that features redox cycles of a Ni catalyst with the in-situ carbonation/calcination of a CO(2) sorbent (dolomite) in a packed bed reactor under alternated feedstreams of fuel-steam and air. The fuel and steam conversion were higher with the sorbent present than without it. Initially, the dolomite carbonation was very efficient (100%), and 98% purity hydrogen was produced, but the carbonation decreased to around 56% with a purity of 95% respectively in the following cycles. Reduction of the nickel catalyst occurred alongside steam reforming, water gas shift and carbonation, with H(2) produced continuously under fuel-steam feeds. Catalyst and CO(2)-sorbent regeneration was observed, and long periods of autothermal operation within each cycle were demonstrated.

Chemical looping reforming of waste cooking oil in packed bed reactor.

Chemical looping steam reforming for hydrogen production from waste cooking oil was investigated using a packed bed reactor. The steam to carbon ratio of 4 and temperatures between 600 and 700 degrees C yielded the best results of the range of conditions tested. Six cycles at two weighted hourly space velocities (WHSV of 2.64 and 5.28 h(-1)) yielded high (>0.74) and low (<0.2) oil conversion fractions, respectively, representing low and high coking conditions. The WHSV of 2.64 h(-1) yielded product concentrations closest to equilibrium values calculated assuming a fresh rapeseed oil composition. Repeated cycling revealed some output oscillations in reactant conversion and in the extent of Ni-NiO conversion, but did not exhibit deterioration by the 6th cycle. The selectivity of CO, CO(2) and CH(4) were remarkably constant over the performed cycles, resulting in a repeatable syngas composition with H(2) selectivity very close to the optimum.