Experimental study of forestry waste gasification: Pinewood chips-grass mixtures

Abstract

An experimental study of forestry waste gasification using pinewood and pinewood-grass mixtures was carried out. The analyzed mixture concentrations of pinewood and grass were 90%–10%, 80%–20%, and 70%–30% (weight based). The study was performed using a laboratory-scale updraft gasifier as the reactor, and air was used as the gasifying agent. Experimental tests were carried out to investigate the influence of the equivalence ratio and the process temperature on gasification performance. The gas composition was analyzed using an infrared syngas analyzer for three levels of equivalence ratios (0.25, 0.30, and 0.34) and at temperatures between 800 °C and 1100 °C. The results showed that compared to 100% pinewood, 90% pinewood–10% grass (MX90%–10%) and 70% pinewood–30% grass (MX70%–30%), gasification of the 80% pinewood–20% grass (MX80%–20%) mixture improves carbon conversion and reduces the amount of char. In the process, a lower heating value ranging from 4.0 to 5.5 MJ/Nm3 was achieved for this mixture. Finally, a new strategy for forestry waste gasification was analyzed, and it was found that for all mixtures there were no significant changes in concentration profiles over the range of temperatures examined. The experimental results of this study will help improve the understanding of syngas production and show that gasification of forestry waste mixtures in an updraft gasifier can be an effective technology for syngas production.