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

Abstract

In this study, the pyrolysis of several Canadian straw biomasses was studied using a thermogravimetric analyzer and a bench-scale horizontal fixed-bed reactor, in order to better understand the devolatilization process and to obtain information about the product yields of these biomasses. The straw biomasses were converted through pyrolysis performed in a fixed-bed reactor at temperatures of 500°C to study the influence of the feedstock on product yields. The effects of various catalysts on product yields are also discussed. When using zeolite catalysts, the bio-oil and bio-char yields of the straw pyrolysis were increased to 46.44% and 38.77%, respectively, while the bio-gas yield was decreased to 13.65%. The use of catalyst zeolite ZY-SS had the most significant effect on overall bio-oil and bio-char yields, increasing the bio-oil yield by about 2% and the bio-char yield by 8%. This catalyst had the most significant effect on the pyrolysis of flax straw, where the bio-oil yield was increased to 46.44%. In the pyrolysis of oat straw, the use of the catalyst consistently decreased the bio-gas yield; however, the bio-oil yield increased the most significantly (43.32%) with the use of catalyst zeolite ZY-NS. The use of zeolite ZY-NS also increased the bio-oil yield during the pyrolysis of barley straw (43.03%).