Abstract:
The pyrolysis and gasification characteristics of pelletized cyanobacteria during chemical looping process with red mud oxygen carrier were investigated. The objective is to evaluate influence of red mud oxygen carrier on the pyrolysis and gasification behavior. In a fluidized bed reactor effects of reaction temperature (750−900 ℃) and oxygen carrier to fuel ratio (0.1−0.7) on syngas distribution, carbon conversion and its conversion rate, syngas content and ratio of H
2/CO in syngas were investigated. The results indicate that the presence of oxygen carrier has remarkably positive effect on the pyrolysis and gasification processes. It improves pressure gradient caused by devolatilization of the sample. Consequently, the volatiles could be released gradually through the relatively developed channels. During chemical looping gasification H
2 content in the syngas has the highest concentration of higher than 45%, followed by CO
2, CH
4 and CO. The increase of reaction temperature or oxygen carrier to fuel ratio leads to increase in carbon conversion. When reaction temperature increases from 750 to 950 ℃, ratio of H
2/CO in the syngas decreases from 7.26 to 4.83. Meanwhile, with increasing oxygen carrier to fuel ratio, ratio of H
2/CO first increases and then decreases, and the peak is 5.6 as oxygen carrier to fuel ratio is 0.5.