Limiting oxygen concentration for coal dusts for explosion hazard analysis and safety

• Presents experimental results on limiting oxygen concentration for Indian coals (volatiles: 27.18% &19.69%) with 20-L Sphere.
• Presents experimental results on influence of reduced oxygen on explosion violence for Indian coals.
• Reports experimental data showing influence of ignition source energy, particle size and moisture content on LOC of coals.
• Data will be used for hazard analysis, designing explosion preventive and explosion severity reduction measures.

Investigation of explosion characteristics of coal dust was undertaken as a part of regular research program at CSIR-CBRI, Roorkee, India, for designing explosion safety measures for coal dust handling installations. This paper presents results of detailed experimental work on determination of Limiting Oxygen Concentration (LOC) and influence of reduced oxygen levels on explosion severity data for two types of coals with varying volatile matter as 27.18% (coal A) and 19.69% (coal B) from Jharia coalfield of India determined at ambient conditions with 20-L Spherical Vessel established at CSIR-CBRI. The effects of coal particle size and moisture content were evaluated. Data presented will be used for hazard analysis, designing explosion preventive measures, and explosion severity reduction by involving the use of inert gases for installations handling pulverized coal with similar nature. The importance of ignition source energy in determining LOC data is highlighted. The data collected lead to an extension of the current data for coal dusts as found in the literature. Limiting oxygen concentrations were found as 7% for coal A and 8% for coal B for the size representative to that used in pulverized coal boilers and moisture content ∼4%.