惰化防爆技术及在煤粉制备系统中的应用

Inerting for the prevention of explosions and its application in pulverized coal preparation system

简述国内关于惰化防爆的标准规范及要求,给出爆炸性环境极限氧浓度的测试方法、测试设备和惰化过程可燃性分布图。分析加压惰化、真空惰化、通流惰化和置换惰化的技术要点、应用范围和惰性气体用量及惰化次数的计算方法,并给出被保护系统惰化氧浓度安全裕量的设定原则和预警分级。以制粉系统为例,分析了惰化工艺流程和维持惰化气氛的条件,并计算了不同氧浓度和监测方式下的初始惰化时间。建议采用惰化保护的系统根据氧浓度设定为三级预警,即最大允许氧浓度MAOC、联锁停车氧浓度TP、惰化系统动作氧浓度SP。

The inerting standards and codes for the prevention of explosion were described. The determination methods and ap paratus of the limiting oxygen concentration （LOC） under ex- plosive environment were introduced, and the combustibility distribution diagram during inerting process was put forward. The inerting methods which including pressurized inerting, vac- uum inerting, flow inerting and replacement inerting and their application region were discussed, and calculations for inerting gas volume and time required for purging were introduced. The setting law of safety margin of inerting oxygen concentration and the alarm rank were put forward. Taking the pulverizing coal preparation system as example, the inerting process and in- erting condition on explosive atmospheres were analyzed, and the time required for initial purging under different oxygen con- centration and different monitor mode was calculated. Three level warning for the system protected by inering was suggested based on the oxygen concentration, namely the maximum allow- able oxygen concentration （MAOC）, trip point （TP） and set point （SP）.