草屑厌氧消化预处理耦合水热炭化研究

Study on anaerobic digestion pretreatment coupled with hydrothermal carbonization of grass

厌氧消化(AD)耦合水热炭化(HTC)技术对园林废弃物的可持续资源化利用具有显著优势和意义。采用草为研究对象,进行了7~28 d的AD预处理,深入探究了AD预处理耦合HTC对水热炭特性及其热解和产物释放特性的影响。其中,AD促进HTC过程主要发生脱羧反应;通过改变木质纤维素构成比例和结构特征有效调控水热炭的功能特性。此外,AD打破了生物质内部致密的刚性结构,促进了水热炭丰富孔隙的形成和比表面积的增加。在生物可降解程度为17.52%(AD 7 d)时,水热炭性能最佳,质量产率、高位热值(HHV)、能量产率和能量密度分别达62.75%、23.81 MJ·kg^(-1)、80.31%和1.28。此外,TG-MS分析结果揭示了AD预处理提高了炭的热稳定性以及热解产物中能源气体的生成,有助于热解气的提质和利用。

Anaerobic digestion(AD)coupled with hydrothermal carbonization(HTC)technology has significant advantages and significance for sustainable resource utilization of garden waste.In this work,the grass was pretreated with AD for 7—28 d.The effects of AD coupled with HTC on the characteristics of hydrochar and its pyrolysis and product release properties were investigated deeply.AD pretreatment promoted mainly the decarboxylation reaction in the HTC process.Besides,the functional properties of hydrochar were regulated effectively by changing the lignocellulose composition ratio and biomass structural characteristics.Noticeably,the dense rigid structure inside the biomass was broken by AD pretreatment,which promoted the formation of rich pores and the increase of the specific surface area of the hydrochar.The best performance of hydrochar was achieved at 17.52% biodegradability(AD 7 d),with mass yield,high heating value(HHV),energy yield and energy density reaching 62.75%,23.81 MJ·kg^(-1),80.31% and 1.28%,respectively.In addition,TG-MS analysis results revealed that AD pretreatment improves the thermal stability of carbon and the generation of energy gas in pyrolysis products,which is helpful for the upgrading and utilization of pyrolysis gas.