Influence of heating rates on the products of high-temperature pyrolysis of waste wood pellets and biomass model compounds

The effect of heating rates ranging from 5 degrees C min(-1) to 350 degrees C min(-1) on the yields of pyrolysis products of wood and its main pseudo-components (cellulose, hemicellulose and lignin) have been investigated at a temperature of 800 degrees C in a horizontal fixed bed reactor. Results showed a successive dramatic increase and decrease in gas and liquid yields, respectively, while the yields of solid products showed a gradual decrease as heating rates increased. Increased gas formation and an increasingly aromatic oil/tar support the theory of rapid devolatilization of degradation products with increasing heating rate, leading to extensive cracking of primary pyrolysis vapours. Solid products with coal-like calorific value and large surface areas were obtained. CO became the dominant gas both on a mass and volume basis, at the heating rate of 350 degrees C min(-1) for all samples except xylan, which also produced a significant yield of CO2 (20.3 wt% and 25.4 vol%) compared to the other samples. Cellulose produced a gas product with highest calorific value of 35 MJ kg(-1) at the highest heating rate. Results also indicate that the three main pseudo components of biomass each exert a different influence on the products of high temperature pyrolysis of woody biomass. (C) 2018 Elsevier Ltd. All rights reserved.