可燃气体空间置换限值研究

Study on Spatial Displacement Limit of Combustible Gases

在全面解析三元组分图构成要素和含义的基础上,分析可燃物质设备投用和停用过程中惰化置换的机理和浓度限值。可燃气体空间置换限值包括设备投用惰化置换时氧气的最高容许浓度(ISOC)和设备停用惰化置换时可燃气体的最高容许浓度(OSFC),二者可由试验和公式计算2种方式获得。与目前惰化置换时通常参照的限制氧浓度(LOC)、燃烧下限(LFL)等参数相比,ISOC和OSFC值可以更准确地表征惰化置换时临界浓度的意义。通过对部分可燃物质的ISOC和OSFC试验值及计算值进行对比分析,证明以LOC为依据计算出的ISOC和OSFC值与试验值具有更高的符合性;指出目前国内惰化置换浓度控制值采用统一规定值这一方式的不足;证明合理利用LFL,LOCI,SOC,OSFC等参数开展可燃气体密闭空间置换限值研究的科学合理性。

The ternary component chart elements and the meaning were comprehensively analyzed, based on which the mechanisms and concentration limits of inert gas exchange during the equipment＇s start-up and shutdown was analyzed. The concentration limits in the combustion gas space includes the ISOC during the inert process of equipment＇s startup and the OSFC during the inert process of equipment＇s shutdown, which could be got by the experiments tests or theoretical calculation. ISOC and OSFC could reflect the critical concentration during the inert process better than the LOC and LFL terms. Comparing the ISOC and OSFC experiments data with the calculation data of several combustible gases, it is concluded that the calculation data of ISOC and OSFC based on the LOC has a higher compliance with the experiment data. The disadvantages of uniform concentration control level utilized in inert gas exchange process of domestic plants were concluded. ItS proved that the LFL, LOC, ISOC and OSFC could be utilized in the research of spatial displacement limit of combustible gases.