市政污泥热干化过程的燃爆风险研究

摘 要：为预防市政污泥热干化过程发生安全事故，利用相关仪器设备研究了污泥在堆积状态和分散状态下的燃爆性质，并结合污泥热干化车间的工艺和设备系统分析了污泥热干化过程存在的安全风险。结果发现：污泥在140 ℃存放24 h未发生自热，当温度升至170 ℃以上时存在放热现象，且在200~220 ℃会发生自燃，这说明当薄层干化工艺系统内部温度大于170 ℃时，发生污泥放热和自燃的可能性较高，而常温堆积储存干污泥的安全风险较低；当污泥粉尘与空气形成混合物时，会发生粉尘爆炸，且爆炸压力随污泥粒度变小而变大，这说明在污泥除尘器内部存在发生污泥粉尘爆炸的危险；污泥被干化时会产生氨气、硫化氢、甲烷等可燃气体，这使得在封闭的干化系统内存在发生气体燃烧或爆炸的危险。这些结果，可以为污泥干化技术发展及设备本质安全设计提供安全技术支撑，同时，对市政污泥干化生产安全管理具有指导意义和参考价值。

Study on the burning and explosion risks of sludge thermal drying process

In order to prevent the safety accident occurrence in the thermal drying process of municipal sludge, the burning and explosion properties of sludge in the state of accumulation and dispersion were analyzed by using relevant instruments. And combined with the technique and equipment of the sludge heat drying workshop, the safety risks in the thermal drying process of the sludge are researched systematically. The results showed that no self-heating occurs when sludge was stored at 140 ℃ for 24 hours, but when the temperature increased to 170 ℃ sludge releases heat, and spontaneous combustion occurs between 200 ℃and 220 ℃. Which means that when the internal temperature of the layer drying process system is greater than 170 ℃, the possibility of sludge exotherm and spontaneous combustion is high, while the safety risk of storing dry sludge at room temperature is low. When the sludge dust and air form a mixture dust, explosion will occur, and the explosion pressure will increase as the sludge particle size becomes smaller, which indicates that there is a danger of sludge dust explosion inside the sludge dust collector. When the sludge is dried, ammonia gas, hydrogen sulfide and methane will be produced, so that there is a danger of gas combustion or explosion in the closed drying system. These results can provide safe technical support for the design of intrinsically safe sludge drying equipment and the development of sludge drying technology. At the same time, it has guiding significance and reference value for the safety of municipal sludge drying.