基于赤泥载氧体的蓝藻化学链热解和气化特性研究

Characteristics of cyanobacteria pyrolysis and gasification during chemical looping process with red mud oxygen carrier

本研究以高挥发分的蓝藻成型颗粒为对象,采用赤泥作为载氧体,开展蓝藻化学链热解和气化特性研究,考察赤泥载氧体对热解和气化行为的影响规律。基于流化床反应器,研究了不同温度(750–900℃)和不同比氧耗(0.1–0.7)下蓝藻成型颗粒化学链热解和气化过程中合成气组分分布、碳转化率和速率、有效合成气组分和合成气中H_(2)/CO的分布规律。研究结果表明,载氧体对蓝藻成型颗粒热解气化过程具有显著的促进作用;载氧体提高了成型蓝藻挥发分释放导致的压力梯度,使得挥发分有相对发达的孔道逐步释放;化学链气化合成气中H_(2)体积分数最高,其值在45%以上,其次分别是CO_(2)、CH_(4)和CO;反应温度和比氧耗的升高能够提升碳转化率;当反应温度由750℃升高到950℃时,合成气中H_(2)/CO的值由7.26下降为4.83;H_(2)/CO随比氧耗的增加呈现先升高后降低的趋势,在比氧耗为0.5时,H_(2)/CO的峰值为5.6。

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.