No abstract

In this work olivine-supported nickel silicate, which was prepared by thermal impregnation is considered as a potential tar removal catalyst for cleaning the gas stream during biomass gasification. Previous work on Ni-olivine catalysts has shown that these catalysts have good activity for the tar-reforming reaction as well as good stability and tolerance to coking. In this work, various characterization techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, laser Raman spectroscopy, temperature programmed reduction, temperature programmed reaction, and subsequent temperature programmed oxidation are employed to reveal the properties of the catalyst surface and bulk as well as their relationship to catalytic activity. Higher thermal impregnation temperatures produce stronger interactions between the active component and support, leading to better coke tolerance. Relative amounts of reducible Ni, Fe species and surface Mg have an influence on catalytic behavior. Moreover, compared to olivine, the Ni 2 SiO 4 /olivine catalyst exhibits good catalytic activity for dry reforming, water gas shift, reverse water gas shift and methanation reactions, as well as the steam reforming reaction.

The adoption of oxidation resistant, high-temperature alloys as alternatives to traditional ceramic interconnect materials for intermediate-temperature solid oxide fuel cells is critical to satisfy the aggressive cost targets necessary for their successful development. The effect of processing conditions on the microstructure and electrical performance of manganese cobaltite oxide coatings for the protection of ferritic stainless steel interconnects has been investigated. Using the standard aerosol spray deposition (ASD) based process which includes a reduction firing operation a highly dense MCO coating is formed that acts as an effective barrier to high temperature oxidation and chromium volatilization. Excellent long-term electrical and microstructural stability of the MCO coating has been demonstrated under application specific conditions. Omitting the reduction firing step is shown to significantly degrade the coating microstructure which is unable to densify sufficiently to form an effective protective oxide coating.

Magnesium nickel silicate (MNS) has been investigated as a catalyst to convert tars and light hydrocarbons to syngas (CO and H 2 ) by steam reforming and CO 2 reforming in the presence of H 2 S for biomass gasification process at NexTech Materials. It was observed that complete CH 4 conversion could be achieved on MNS catalyst granules at 800-900 °C and a space velocity of 24,000 mL/g/h in a simulated biomass gasification stream. Addition of 10-20 ppm H 2 S to the feed had no apparent impact on CH 4 conversion. The MNS-washcoated monolith also showed high activities in converting methane, light hydrocarbons and tar to syngas. A 1200 h test without deactivation was achieved on the MNS washcoated monolith in the presence of H 2 S and/or NH 3 , two common impurities in gasified biomass. The results indicate that the MNS material is a promising catalyst for removal of tar and light hydrocarbons from biomass gasified gases, enabling efficient use of biomass to produce power, liquid fuels and valuable chemicals.

NexTech Materials is developing solid oxide fuel cell stacks based on its patent-pending FlexCell™ design. The FlexCell is an electrolyte-supported planar cell with unique characteristics that enable high electrochemical performance and long term durability. Demonstrated attributes of NexTech's FlexCell include scalability to large areas and tolerance to high levels of sulfur impurities in fuel. NexTech is building and testing stacks with power outputs in the 1-10 kW range, and has demonstrated that these stacks deliver targeted power outputs at high voltage and high fuel utilization.