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Abstract: Densified biomass pellets using waste wood sawdust (S) as main materials and wrapping paper fiber (P) as “solid bridge”, named as P/S-BPs, was prepared by a hydraulic press powder pelletizer under room temperature and pressure lower than10MPa. The effects of the addition of P to S and the compressed pressure on the density, resiliency (R), abrasion resistance (AR), impact resistance index (IRI)) and the combustion behavior of the P/S-BPs were investigated. The results showed that the addition of P to S greatly reduced the negative effects of resiliencies on the densities and mechanical properties of P/S-BPs during storage. For example, P/S-BPs compressed at 6MPa in a P/S mass ratio of 1–3 showed the smooth surface and low resiliency of 10% with a high relaxed density of 1.08kgm−3. This is due to the strengthened interlocking bonds through fabricating “solid bridge” and increasing attracting force by adding P to resist the disruptive force created by elastic recovery even under low pressure. Combustion results showed that the addition of P decreased the soot index (SI) due to the lower devolatilization rate and burnout rate, and increased the HHV per unit volume because of its high relaxed density. Thus, compression of waste P and S in a P/S mass ratio of 1–3 at room temperature under 6MPa is a cost-effective process to produce densified sustainable bio-fuel from waste S and P as well as dispose them. [Copyright &y& Elsevier]

Abstract: Evolutionary behavior of syngas chemical composition and yield have been examined for paper and cardboard at three different temperatures of 800, 900 and 1000°C using CO2 as the gasifying agent at constant flow rate. Specifically the evolution of syngas chemical composition with time has been investigated. Pyrolysis of the sample was dominant at the beginning of the gasification process as observed from the high initial devolatilization of the sample followed by char gasification of material to form syngas for a long period of time. Results provided the role of gasification temperature on kinetics of the CO2 gasification process. Increase in gasification temperature provided increased conversion of the sample material to syngas. Thus the sample conversion to syngas was low at the low temperature of 800°C while at elevated temperatures of 900 and 1000°C substantial enhancement of the kinetics process occurred. The evolution of extensive reaction rate of carbon-monoxide was calculated. Results show that increase in temperature increased the extensive reaction rate of carbon-monoxide. The global behavior of syngas chemical composition examined at three different temperatures revealed a peak in concentration of H2 to exhibit after few minutes into the gasification that changed with gasification temperature. At 800°C gasification temperature peak in H2 was displayed at 3min into gasification while it decreased to only 2min, approximately, at gasification temperatures of 900 and 1000°C. The effect of reactor temperature on CO mole fraction has also been examined. Increase in the gasification temperature enhances the mole fraction of CO yields. This is attributed to the increase in forward reaction rate of the Boudouard reaction (). The results show important role of CO2 gas for the gasification of wastes and low grade fuels to clean syngas. [Copyright &y& Elsevier]