城镇污水污泥低温氧化放热特性的恒温量热分析

针对干化后城镇污水污泥的低温氧化和自加热问题，采用恒温量热分析方法对含水率为10%~70%（干基）的污泥在5个温度（30~70℃）下的低温氧化放热特性进行了实验研究。结果表明:污泥的低温氧化放热主要有3种机制，包括微生物生化氧化、无机成分（Fe/S/O系统）氧化和有机质化学氧化，污泥的低温氧化放热特性是3种机制综合表现的结果，其交叉重叠共同决定了污泥低温下的自加热特性。含水率和环境温度会影响污泥低温氧化放热过程中的各热源贡献并导致主要热源的转变，同时也会影响3种机理各自的放热特性。水分和温度增加都会使污泥的放热增强，即自加热能力变强，从而加大污泥自燃的风险。

ISOTHERMAL CALORIMETRIC ANALYSIS OF EXOTHERMIC CHARACTERISTICS OF MUNICIPAL SEWAGE SLUDGE DURING LOW TEMPERATURE OXIDATION

Aiming at the problems of low temperature oxidation and self-heating of dried municipal sewage sludge, the exothermic characteristics of low temperature oxidation of the sludge with moisture content of 10%~70% (dry basis) at different temperatures (30℃~70℃) were studied with isothermal calorimetry. The results showed that the low temperature oxidation heat generation had three major mechanisms, including microbial biological oxidation, inorganic matters (Fe/S/O system) oxidation, organic matters chemical oxidation. The low temperature oxidation exothermic characteristics of the sludge were resulted from their comprehensive performance, and the overlapping of these three mechanisms jointly determined the self-heating characteristics of the sludge at low temperatures. The moisture content and ambient temperature affected the contribution of each heat source in process of sludge low-temperature oxidation, leading to the transformation of the main heat source and also having impact on the respective heat release characteristics of the three mechanisms. Increasing temperature and moisture content enhanced the heat generation of the sludge, then the self-heating potential became stronger, thus increased the risk of spontaneous combustion.