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.

Effect of fuel and lube oil sulfur on the performance of a diesel exhaust gas continuously regenerating trap.

The continuously regenerating trap (CRT) is a diesel exhaust emission control that removes nearly all diesel particulate matter on a mass basis, but under some circumstances oxidation of sulfur leads to the formation of nanoparticles. The objective of the four year study was to determine CRT performance under controlled, real-world, on-road conditions, and to develop quantitative relationships between fuel and lubrication oil sulfur concentration and particle number exhaust emissions. It was shown that nanoparticle emissions are minimized by the use of ultralow sulfur fuels and specially formulated low sulfur lubrication oil. Nanoparticle emissions increased with higher exhaust temperatures. Fuel and lubrication oil sulfur increased the particle concentration by, on average, 36 x 10(6) and 0.14 x 10(6) part/cm3 for each 1 ppm increase in sulfur. On the other hand there was a decrease in nanoparticle emissions by the CRT as the system aged.