Performance and characteristics of continuous, fluidized bed pyrolysis of reed black liquor

Abstract

Fluidized bed pyrolysis is a promising technology for recovering value from reed black liquor (RBL) but it can be limited by agglomeration of the bed material and loss of fluidization. To address this challenge, laboratory experiments examined the continuous, fluidized bed pyrolysis of RBL using two different bed materials at temperatures ranging from 530 to 780 °C. Pyrolysis with silica sand as the bed material showed sintering within 120 s and loss of fluidization at a bed temperature of 680 °C. Pyrolysis with calcium-based zeolite as the bed material retained fluidization for the entire test period of 30 min at all temperatures examined. Increasing pyrolysis temperature with the calcium-based zeolite increased H2 generation and decreased tar production, with the highest temperature examined (780 °C) providing the best performance. Fluidized bed combustion of the pyrolysis char (both at 780 °C) recovered 87% of the sodium in the RBL. Pyrolysis of RBL using fluidized bed technology with a calcium-based zeolite bed material is feasible and effective.