Experimental Research On Influencing Factors Of Minimum Ignition Temperature Of Coal Dust

The minimum of the ignition temperature of dust cloud is an essential characteristic parameter.The thesis makes use of experiments to study the factors that influence the minimum of the ignition temperature.There are four coal samples of different grain sizes respectively 44μm、62.5μm、81.5μm、119μm and we try to measure their respective minimum ignition temperature by using minimum ignition temperature instrument.Besides,we did a data analysis of another four bituminous coal samples with a different volatile content of 18.99%,27.52%,32.20%,39.74%.The aim of the data analysis is to study the influence rule of the dust pressure,the grain size and the volatile to the minimum of ignition temperature of coal dust cloud.Apart from this,the analysis also involves the research about the inhibiting effect of pure rock powder,inert powder including silicon dioxide and silica and calcium carbonate.The result shows that there exists the best dust pressure.That is to say,when the dust pressure is the best one,the minimum of ignition temperature is the lowest.Also,the grain size has an important influence on the minimum of ignition temperature.The larger the grain size is,the higher the ignition temperature will be.However,there is actually a mixture of the coal dust of different grain sizes rather than a pure grain size.In the experiment,we mixed the two different grain sizes of 119μm and 62.5μm in two different proportions to study the impact trend to the minimum of ignition temperature.Compared with the pure grain size,we find that these two situations have the same variation tendency.About the effect of inhibiting explosion,the inert powder is better than pure rock powder.Between the two inert powder inhibitors,silica and calcium carbonate is better than silicon dioxide.The former should be the first choice.But the experiment also shows that adding some silica and calcium carbonate to silicon dioxide can improve the effect of silicon dioxide of inhibiting the combustion of pulverized coal.Therefore,we can increase the inhibition effect through matching different inert powder in our actual production practice.