Gasification provides a mechanism to convert solids, such as biomass, coal, or waste, into fuels that can be easily integrated into current infrastructure. This paper discusses the use of residual char from a biomass gasifier as a catalyst for tar decomposition and presents an investigation of the catalytic properties of the char. Poplar wood was gasified in a fluidized bed reactor at temperatures ranging from 550 to 920 °C in reaction environments of 90% steam/10% N2 and 90% N2/10% CO2. The properties of the char recovered from the process were analyzed, and the catalytic performance for hydrocarbon cracking reactions was tested. Brunauer–Emmett–Teller (BET) measurements showed that the surface area of the char was higher than conventional catalyst carriers. The surface area, which ranged from 429 to 687 m2 g–1, increased with temperature and reaction time. The catalytic activity of the char was demonstrated through testing the catalytic decomposition of methane and propane to produce H2 and solid carbon...

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Catalyst Properties and Catalytic Performance of Char from Biomass Gasification

The influence of the temperature and the partial pressure of water vapour on the kinetic of surface reduction of hydroxyapatite during calcination treatment was studied. The water vapour catalysed the growth of HAP grains. A theoretical model was proposed and compared with the experimental data. It allowed the identification of the mechanisms of surface reduction and the determination of the kinetic laws. At low temperature (T<850 °C), grain coalescence occurs without densification. The superficial diffusion is the predominant mechanism and it is controlled by the adsorption–desorption of water vapour on the surface of the HAP grains. At higher temperature, the densification mechanisms are effective.

Sintering of calcium phosphate hydroxyapatite Ca10(PO4)6(OH)2 I. Calcination and particle growth

https://hal.archives-ouvertes.fr/hal-01634402/document

The kinetics of surface area reduction during isothermal sintering of hydroxyapatite adsorbent

Sintering of non-stoichiometric NiO, CoO and Co3O4 catalysts

https://digital.library.unt.edu/ark:/67531/metadc788354/m2/1/high_res_d/859920.pdf

An nth-order Gaussian energy distribution model for sintering

The surface-area reduction kinetics for the intermediate stage of sintering was analyzed. The high sintering rate in the initial stage results from the initially large curvature gradients. In the intermediate stage these gradients are reduced and the surface-area reduction kinetics shift to a dependence on the mass transport rate associated with grain growth. This is a much slower process. (FS)

R. M. German

Papers

Surface Area Reduction Kinetics During Intermediate Stage Sintering