Abstract:

Biomass is the fourth largest source of energy and conventional incineration will not only pollute the environment, but also is a waste of energy. Hydrothermal carbonization (HTC) is a novel biomass conversion technology, yielding carbonaceous products (HTC char) favorable for wider range of applications. The impact of temperature and reaction time on hydrothermal carbonization of microcrystalline cellulose and carbon distribution was studied, and physical, chemical, thermal and structural characteristics of HTC char also investigated. The results show that during hydrothermal carbonization of microcrystalline cellulose a significant fraction of initially present carbon, about 71%-75%, is stayed in HTC char, while only a small fraction of the carbon is transferred the liquid and gas-phases. As the temperature and reaction time increase, the HTC char yield and O/C atom ratio decrease, and its heat value increases. SEM images show that HTC char consists of aggregates of microspheres. FTIR spectra indicate that dehydration and aromatization processes take place during hydrothermal carbonization and HTC char possesses hydroxyl groups and carbonyl groups.

Key words: cellulose, hydrothermal carbonization, carbon distribution, HTC char, characterization

摘要：

生物质废弃物是当今世界上的第四大能源,传统的焚烧处理方式不仅会污染环境,还会浪费能源。水热碳化是一种高效的废弃生物质资源化技术。考察了反应温度和停留时间对纤维素水热碳化碳分布的影响,并对碳化物的物理化学特性、微观结构进行了研究,以及从反应机理角度进行解释。结果表明,原料中的碳大部分都保留在了碳化物中,占71%～75%,其余部分被转移至液相和气相。随着温度和时间的增大,碳化物的产率降低,热值升高,O/C原子比降低。SEM显示当温度达到220℃时,碳化物表面开始形成微球结构,且随着温度和时间的增大,微球结构均一性、分散度越来越好。FTIR表明碳化物表面生成羟基和羰基等官能团,水热碳化过程中会发生脱水和芳香化反应。

关键词: 纤维素, 水热碳化, 碳分布, 碳化物, 表征