597 / 2019-01-20 12:05:08

Cofiring characteristics and kinetic analysis of Distiller’s grains biomass with coal

Distiller’s grains; bituminous coal; cofiring; thermogravimetric analysis; kinetic analysis.

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Abstract
The combination of biomass with coal combustion may be one of effective methods to both reduce CO2 emissions and improve energy utilization efficiency in coal-fired power stations. This study aims to investigate combustion characteristics of distiller’s grains with bituminous coal (BC) under different conditions using a thermo-gravimetric analyzer. And the reaction kinetic analysis has also been carried out. The results demonstrate that in comparison of single coal combustion, as the proportion of distiller’s grains (DG) is increased from 15% to 50%, the ignition temperature (Ti) greatly decreases (from 283.4℃to 183.9℃) and the burnout temperature(Tb) slightly decreases (from 680.3℃to 671.4℃). The reaction activation energy (E) in fixed carbon combustion stage becomes smaller. Therefore, the comprehensive combustion index (CCI) improves. For the distiller’s grains, coal and distiller’s grains-coal blended fuels, in the O2/CO2 mixture, Ti has been promoted about 15℃ while Tb has been not change much. However, E in the fixed carbon combustion stage and CCI relative to the O2/N2 mixture decline. In addition, for the 15%DG+85%BC under the O2/CO2 atmosphere, with the increasing of O2 concentration from 10% to 40% , Ti changes in a small range but Tb goes down from 745.8℃ to 641.4℃, and E in the fixed carbon combustion stage and CCI are improved. As enhancing heating rate from 10℃/min to 30℃/min, the values of Ti decrease (from 281.4℃ to 244.9℃), but the values of Tb increase significantly (from 662.8℃ to 745.8℃). E in the fixed carbon combustion stage reduces and CCI has also been improved. This research would provide useful information to theoretical basis and practical reference for optimizing the distiller’s grains/coal cofiring technology.