Catalytic steam reforming of glycerol for H 2 production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400-700C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in-situ CO 2 removal. The product gases were measured by online gas analyzers. The results show that H 2 productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500C. The results suggest an optimal temperature of ~500C for the glycerol steam reforming with in-situ CO 2 removal using calcined dolomite as the sorbent, at which the CO 2 breakthrough time is longest and the H 2 purity is highest. The * Author to whom correspondence should be addressed. Tel: 44 -113-3432503; Fax: 44 -113-2467310, v.dupont@leeds.ac.uk. 2 shrinking core-model and the 1D diffusion model describe well the CO 2 removal under the conditions of this work.

Steam reforming of the crude glycerol by-product of a biodiesel production plant has been evaluated experimentally at atmospheric pressure, with and without in-situ CO 2 sorption, in a continuous flow fixed-bed reactor between 400 and 700 °C. The process outputs were compared to those using pure glycerol. Thermodynamic equilibrium calculations were used to assess the effect on the steam reforming process of the main crude impurities (methanol and four fatty acid methyl esters). The crude glycerol and steam conversions and the H 2 purity reached 100%, 11% and 68% respectively at 600 °C. No CH 4 was found at and above 600 °C. Steam reforming of crude glycerol with in-situ CO 2 removal is shown to be an effective means of achieving hydrogen purity above 88% in pre-CO 2 breakthrough conditions.

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 °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 hr -1 ) yielded high (>0.74) and low (<0.2) oil conversion fractions respectively, representing low and high coking conditions. The WHSV of 2.64 hr -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 6 th 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.

Pimenidou, P, Rickett, G, Dupont, V and Twigg, MV (2010) AbstractHigh purity hydrogen (>95%) was produced at 600 °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.

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