Co-firing of biomass with coals Part 1. Thermogravimetric kinetic analysis of combustion of fir (abies bornmulleriana) wood

The chemical composition and reactivity of fir (Abies bornmulleriana) wood under non-isothermal thermogravimetric (TG) conditions were studied. Oxidation of the wood sample at temperatures near 600 A degrees C caused the loss of aliphatics from the structure of the wood and created a char heavily containing C-O functionalities and of highly aromatic character. On-line FTIR recordings of the combustion of wood indicated the oxidation of carbonaceous and hydrogen content of the wood and release of some hydrocarbons due to pyrolysis reactions that occurred during combustion of the wood. TG analysis was used to study combustion of fir wood. Non-isothermal TG data were used to evaluate the kinetics of the combustion of this carbonaceous material. The article reports application of Ozawa-Flynn-Wall model to deal with non-isothermal TG data for the evaluation of the activation energy corresponding to the combustion of the fir wood. The average activation energy related to fir wood combustion was 128.9 kJ/mol, and the average reaction order for the combustion of wood was calculated as 0.30

Effect of the mineral matrix in the reactions of shales. Part 2. Oxidation reactions of Turkish Goynuk and US Western reference oil shales

The effect of the mineral matrix of Turkish Goynuk and US Green River oil shales and air diffusion on the conversion of organic material in oxidation reactions was investigated in the present study. The material washed with HCl from the original oil shales, mainly carbonates of calcium and magnesium, had a mild catalytical effect and the material washed with HF, silicate minerals, had an inhibition effect during oxidation reactions of organic material. The overall reaction orders from the kinetic analysis were found to be pseudo-first-order. The magnitude of the activation energies of oxidation reactions at equal heating rates changed as E-a (HCl washed shale) > E-a (original shale) > E-a (HCl + HF washed shale). The rate of reaction depends on the rate of transport of the gas into the zone of reaction by diffusion. It was observed that the diffusion of oxygen into the organic matrix was the major resistance controlling the rate of oxidation reactions