Experimental Study On Co-firing Of Anthracite And Distiller’s Grains

The surrounding areas of southwest China have abundant anthracite resources,but its volatile matter content is low,ash content is high,harmful elements in coal are complex,combustion and disposal are difficult.Research on the efficient and environmentally friendly use of anthracite coal is an important topic in the utilization of coal resources.Combined with the by-product of liquor making,distiller’s grains,which has the characteristics of high calorific value,high water content and easy metamorphism.The efficient resource utilization of distiller’s grains is realized by blending distiller’s grains with anthracite.Therefore,this paper aims to improve the combustion performance of anthracite and solve the problem.As for the utilization of distiller’s grains as resource,the combustion characteristics and ash melting characteristics of coal and distiller’s grains were studied.The effect of mixture ratio of distiller’s grains、combustion temperature and excess air rate on the burnout rate and NO emission characteristics of the blending coal are investigated by using the drop tube furnace platform.The results show that blending with distillers’ grains can improve the burnout rate of anthracite and reduce NO emission.With the blending ratio of distiller’s grains increases from 5% to 15%,the burnout rate reaches the highest at 5%,and then begin to decline.The increase of excess air rate and combustion temperature promotes the combustion reaction,which improved the burnout rate of anthracite,but also led to the increase of NO emission.An experiment is conducted on the flat-flame assisted entrained flow reactor to observe the effect of mixed distillers’ grains on the flame morphology of anthracite.The results showed that the distillery grains with high volatile content can promote the ignition of anthracite and keep the flame stable.The results show that the melting point of anthracite ash can be reduced by mixing distillers’ grains.The content of alkali metal element K in the ash melting region is obviously higher than that in other regions,which is a key factor affecting the ash characteristics.A higher combustion temperature will increase the reactivity of alkali metal and alkaline earth metal elements,and produce more substances with low melting point,which reduces the ash melting point.The increase of excess air rate has no significant effect on the morphology of ash,and has no obvious effect on the improvement of the melting characteristics of ash.The increase of oxygen concentration promotes the conversion of trivalent iron ions to form stronger flux.Finally,considering calorific value,burn out rate,slagging index and price,a fuzzy mathematical approach is used to evaluate the options,and the conclusion is that the scheme of anthracite blended with 5% distiller’s grains is the best.