Influence of reaction conditions and red brick on fast pyrolysis of rice residue (husk and straw) in a spout-fluid bed

Fast pyrolysis of rice residue (husk and straw) was carried out in a spout‐fluid bed. In this study, the effects of reaction conditions (pyrolysis temperature, flow state, feed rate and feed size) and red brick (RB) using as bed material on the pyrolysis product distribution and bio‐oil qualities were investigated. Two phases composed the bio‐oil obtained from fast pyrolysis of rice residue. The results showed that at around 460°C the bio‐oil yields could reach the maxima, which were 48.2% and 53.1% for rice husk and straw respectively. Due to the heat and mass transfer motion, higher yields of bio‐oil and organics in upper phase could be obtained in spout‐fluid state compared with fluid state, which indicated that the spout‐fluid state might be more beneficial for fast pyrolysis. In additional, lower feed rates and larger particle sizes were found unfavourable for the bio‐oil production. The application of RB as bed material instead of quartz sand (QS) resulted in less bio‐oil and char, but more organics in upper phase. Furthermore, the quality of the upper phases was improved by RB, with the characteristics of high heating value and lower water and oxygen contents than QS. © 2011 Canadian Society for Chemical Engineering