在石化企业中,燃料气经常是含氢气体混合物,氢气在混合物中体积分数为27％时最大试验安全间隙(MESG)为0.29 mm,爆炸性级别为ⅡC,石化设备中的燃料气中氢体积分数达不到27％,燃料气的MESG应当大于0.29 mm.通过分析国家和行业标准,对用于含有氢气的气体混合物燃料气防爆阻火器级别进行分析,认为爆炸性级别应当低于ⅡC,为ⅡA或者ⅡB,最确切的做法是将气体混合物的组成和操作条件送有关单位,应当按照GB3836.11的方法试验确定MESG,根据MESG确定含氢气体混合物爆炸性级别.%In petrochemical plants, fuel gas is often a mixture containing hydrogen. The maximum experiment safety gap ( MESG) is 0. 29 when the hydrogen in mixture gas is 27% and explosion class is II C. As the hydrogen in fuel gas in petrochemical equipment is lower than 27% , the MESG of fuel gas should be greater than 0. 29. The study of applicable national and industrial codes and standards as well as the analysis of class of explosion-proof flame arrestor for gas mixture containing H2 conclude that the explosion class of flame arrestor should be lower than II C, I. E. Either II A or II B. The most accurate way is to send the data of compositions of gas mixture and operation conditions to qualified institutions to determine MESG based upon the experiment in accordance with GB 3836. 11 and explosion class of gas mixture containing H2 based upon MESG.
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