Pyrolysis of wheat straw pellets in a pilot‐scale reactor: Effect of temperature and residence time

Abstract Pyrolysis of two types of pellets ( T 1 : 100% wheat straw, and T 2 : 70% wheat straw; 10% sawdust, 10% biochar, and 10% bentonite clay) was performed in a pilot‐scale reactor under a nitrogen environment at 20°C to 700°C. This was to investigate slow pyrolysis yields and gas composition as a function of temperature and residence time. The experimental data were obtained between 300°C and 600°C, with a residence time of 90 min, a nitrogen flow rate of 50 cm 3 /min, and a heating rate of 20°C/min. The results indicated that the maximum pyrolysis temperature is 605°C with a residence time of 55 min. The product analysis showed that the proportion of gas was higher than that of biochar and bio‐oil. The conversion efficiency increased with higher temperatures and varied between 66% and 76%. The results showed that carbon dioxide was the main component in the produced gas, and the maximum gas concentration was 63.6% at 300°C for T 1 . The higher temperature and longer residence time increased the syngas (CO + H 2 ) composition for both T 1 and T 2 treatments. Nevertheless, the produced biochar had a high carbon content and retained a high calorific value, indicating slow pyrolysis is the ideal utilization route of wheat straw pellet biomass for biochar.