Abstract: There will be explosive gas atmosphere in the process of production, processing, handing, transportation or storage of petrochemical enterprises. Therefore, it is necessary to design electrical equipment in explosive gas atmosphere and reasonably select the protection grade of electrical equipment in hazardous atmosphere. Maximum experimental safe gap(MESG)is an important explosion index of explosive gas mixture. This paper mainly analyzes the calculation method of MESG of explosive gas mixture, discusses the application scope of different calculation methods, introduces the latest empirical formula of MESG calculation of explosive gas mixture, and gives a simplified calculation method of explosive gas mixture grading. It provides the calculation basis to determine the grade of explosive gas mixture, and provides an important basis for the design and selection of electrical equipment in petrochemical enterprises.

Key words: petrochemical enterprises, explosive gas mixture, equipment protection grade, MESG

摘要： 石油化工企业在生产、加工、处理、转运或储存过程中会出现爆炸性气体环境,应对爆炸性气体环境的电力装置进行合理设计,选择危险环境下电气设备的防护等级。最大试验安全间隙(MESG)是爆炸性气体混合物的重要爆炸指数,分析了爆炸性气体混合物的最大试验安全间隙的计算方法,论述了不同计算方法的适用范围,引出最新的爆炸性气体混合物MESG计算经验公式,并提出一种爆炸性气体混合物分级简化计算方法,为确定爆炸性气体混合物的分级提供计算基础,为石油化工企业电气设备设计、选型提供依据。

关键词: 石油化工企业, 爆炸性气体混合物, 设备防护级别, 最大试验安全间隙