Experimental Study On Co-firing Characteristics Of Coal And Distillers' Grains/Sludge Blends

The environmental pollution and high energy consumption caused by the coal-dominated energy structure in my country have always been the focus of attention at home and abroad.The co-firing of biomass with coal can save coal resources and achieve efficient use of biomass.In this paper,distiller's grains(DG)?sludge(SD)and anthracite(BC)were selected.At the same time,blended samples(DG/BC)and(SD/BC)were prepared for experimental research,it aims to provide basic experimental data and operational guidance reference for future power plant.Firstly,the thermo-gravimetric analysis experimental system was used to study the effects of the mixture ratio,combustion atmosphere,oxygen concentration,and heating rate on the ignition,burnout and comprehensive combustion characteristics of the co-firing of distiller's grains and anthracite.And we carried out the calculation of reaction kinetics.The results demonstrate that increasing the proportion of distiller's grains in coal results in the ignition temperature and burnout temperature gradually decreases.The apparent reaction activation energy of the fixed carbon combustion stage is reduced,and the comprehensive combustion characteristics are improved.Compared with 21%O₂/79%N₂,the change trend of weightlessness curve in 21%O₂/79%CO₂atmosphere is similar.The ignition and burnout temperatures are slightly higher,and the comprehensive combustion index is slightly lower.Under the O₂/CO₂ atmosphere,the thermo-gravimetric curve moves to the low temperature region,as the oxygen concentration increases.The apparent activation energy and pre-finger factor of the fixed carbon combustion stage are increased,and the comprehensive combustion characteristics are improved,as the oxygen concentration increases.As the heating rate rising,the thermo-gravimetric curve moves to the high temperature region.The apparent activation energy of the fixed carbon combustion stage decreases and the comprehensive combustion index increases.Secondly,the co-firing characteristics of sludge and anthracite were studied.The result shows that the ignition temperature,burnout temperature,and apparent activation energy of the fixed carbon combustion stage all decrease,with the increasing of the sludge blending ratio.But the comprehensive combustion index rises first and then decreases,reaching a maximum at about 15%.Compared with 21%O₂/79%N₂,under 21%O₂/79%CO₂ atmosphere,the ignition is delayed,the burn-out temperature is higher,and the comprehensive combustion index is lower.Under the O₂/CO₂ atmosphere,as the oxygen concentration increases,the thermo-gravimetric curve moves to the low temperature region.The burnout temperature drops significantly.The apparent activation energy and pre-finger factor of the fixed carbon combustion stage are increased and the combustion is more intense.The comprehensive combustion characteristics are improved.As the heating rate increases,the thermo-gravimetric curve moves to the high temperature region.The apparent activation energy of the fixed carbon combustion stage decreases and the comprehensive combustion index increases.Finally,the static combustion experiment system was used to investigate the NO generation characteristics of the blended samples(DG/BC)and(SD/BC).The results show that the NO conversion rate of the experimental samples decreased,with the increase of the biomass blending ratio.Relative to 21%O₂/79%N₂,in the 21%O₂/79%CO₂ atmosphere,the peak NO concentration of the fuel and the amount of NO produced is lower.In an air atmosphere,as the temperature rises from 800?to 1000?,the total amount of NO produced is increasing.