Xiaotao Bi

A scientific review addresses the current development of size-dependent, shape-selected, and composition-controlled carbon-supported Pt-alloy electrocatalysts for enhancing electrochemical catalytic performance in polymer electrolyte membrane fuel cells (PEMFCs). It starts with an overview of carbon support in carbon-supported Pt-alloy electrocatalysts and proceeds to the theoretical studies on the impact of Pt-alloy particle size, shape, and composition, and the experimental research on the particle size, shape, and composition of Pt-alloy catalysts. It particularly emphasizes on strategies to control particle size, shape, composition, and their impacts on catalyst activity toward the oxygen reduction reaction.

In the current energy scenario, the production of heat, power and biofuels from biomass has become of major interest. Amongst diverse thermochemical routes, gasification has stood out as a key technology for the large-scale application of biomass. However, the development of biomass gasification is subjected to the efficient conversion of the biochar and the mitigation of troublesome by-products, such as tar. Syngas with high tar content can cause pipeline fouling, downstream corrosion, catalyst deactivation, as well as adverse impact on health and environment, which obstruct the commercialization of biomass gasification technologies. Since the reduction of tar formation is a key challenge in biomass gasification, a comprehensive overview is provided on the following aspects, which particularly include the definition and complementary classifications of tar, as well as possible tar formation and transformation mechanisms. Moreover, the adverse effects of tar on downstream applications, human health or environment, and tar analyzing techniques (online and off-line) are discussed. Finally, the primary tar removal strategies are summarized. In this respect, the effect of key operation parameters (temperature, ER and S/B), catalysts utilization (natural and supported metal catalysts) and the improvement of reactor design on tar formation and elimination was thoroughly analyzed.

New data enable targeted policy to lessen GHG emissions

An engineering economic analysis of a biomass pelleting process was performed for conditions in North America.The pelletization of biomass consists of a series of unit operations: drying, size reduction, densifying, cooling, screening, andwarehousing. Capital and operating cost of the pelleting plant was estimated at several plant capacities. Pellet productioncost for a base case plant capacity of 6 t/h was about $51/t of pellets. Raw material cost was the largest cost element of thetotal pellet production cost followed by personnel cost, drying cost, and pelleting mill cost. An increase in raw material costsubstantially increased the pellet production cost. Pellet plants with a capacity of more than 10 t/h decreased the costs toroughly $40/t of pellets. Five different burner fuels wet sawdust, dry sawdust, biomass pellets, natural gas, and coal weretested for their effect on the cost of pellet production. Wet sawdust and coal, the cheapest burner fuels, produced the lowestpellet production cost. The environmental impacts due to the potential emissions of these fuels during the combustion processrequire further investigation.