Catalytic pyrolysis of straw biomasses (wheat, flax, oat and barley straw) and the comparison of their product yields

Abstract

Biomass can be converted through a biochemical and also thermochemical process. Pyrolysis is considered one of the thermochemical processes that can be used to breakdown biomass into a liquid product called bio-oil. Pyrolysis of Canadian straw biomasses was studied using a thermogravimetric analyzer (TGA) and a bench-scale horizontal fixed bed reactor, to understand the devolatilization process and, to obtain information about their product yields. In this work, the results of experimental studies on the pyrolysis of several Canadian biomasses are described. The pyrolysis of straw biomass was performed in a fixed-bed reactor at temperatures of 500°C, to study the influence of the feedstock on product distribution. The pyrolysis products were analyzed, and the effect of the catalyst on the product yield is also discussed. The yield of bio-oil and bio-char of the straw pyrolysis using zeolite catalysts was increased up to 46.44% and 38.77%, respectively; while the bio-gas yield was decreased to as low as 13.65%. The use of catalyst 2 (Zeolite YH2.2) had the most significant effect in increasing the yield of bio-oil about 2% and bio-char yield up to 8%. The use of catalyst number 2 also showed the most significant effect during pyrolysis of flax straw by increasing the bio-oil yield up to 46.44%. In the pyrolysis of oat straw, the use of catalyst consistently decreased the bio-gas yield; however, the bio-oil yield increased the most (43.32%) with the use of catalyst 1 (Zeolite YS2.2). The use of catalyst 1 also increased the bio-oil yield during the pyrolysis of barley straw (43.03%). © 2014 WIT Press.