不同温度下反应溶液对麦秆水热碳化的影响

Influence of reaction solution on hydrothermal carbonization of wheat straw at different temperatures

为了研究回收溶液中生物质的水热碳化过程和产物特性,在间歇式反应釜中,以麦秆为实验原料,麦秆水热反应溶液为溶剂,进行反应温度为160~240℃,停留时间为120 min的水热碳化实验研究。研究结果表明:同纯水作溶剂相比,回收溶液为溶剂时,随反应温度的升高,固体产物产率增加2%~5%,有序化和芳香化程度逐渐升高,热稳定性增强;液体产物中还原糖浓度从160℃时的7.572 g/L下降至240℃时的2.753 g/L,乙酸浓度从2.698 g/L增加至6.852 g/L,糠醛和5-HMF浓度变化幅度很小;乙酸的累积对水热碳化过程有催化作用。回收利用反应溶液有利于液体产物中碳的固存和反应强度的降低。

In this present work, the HTC aqueous solution was reused to mainly investigate the effect of recovered solution on the characteristics of HTC products. Wheat straw was treated in a pressure reactor. The aqueous solution was separated and reused in wheat straw HTC at various temperatures （160 -240 ℃ ） for 120 min. The results showed that with the increase of reaction temperature, the hydrochar yield with the recovered solution was about 2%-5% higher than that under water environment. Moreover, the hydrochar of wheat straw by using recovered solution presented more thermal stability, better aromatization and carbonization structure than that using water. Whereas in the recovered liquid HTC, the concentration of reducing sugars sharply decreased from 7.572 g/L at 160 ℃ to 2.753 g/L at 240 ℃, instead, that of acetic acid obviously increased from 2.698 g/L to 6.852 g/L. There were slight variations in the concentrations of furfural and 5-HMF in liquid products over the range of temperature. HTC reaction could be promoted by the accumulation of acetic acid. The recovered solution might be advantageous to sequestrate carbon and decrease reaction severity.