Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable vol...Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion.In the present work,experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal.Heat-affected coal(31%ash and 5300 kcal/kg GCV)collected from Jharia coalfield were blended with thermal coal(28%ash and 5650 kcal/kg GCV)in different ratios of 90:10,80:20,70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities.Burning characteristics of all the coals were carried out using TGA.Various combustion parameters such as ignition temperature,peak temperature,burnout temperature,ignition index,burnout index,combustion performance index,rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process.Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.展开更多
The volume hypothesis,a theory about the energy scale of comminution,was adopted to analyze the degradation behavior of lump coal under different heating time.The breakage energy of chars was determined by a compressi...The volume hypothesis,a theory about the energy scale of comminution,was adopted to analyze the degradation behavior of lump coal under different heating time.The breakage energy of chars was determined by a compression test,and the results show that the ultimate strength of chars decreased at the early stage during the heating process,resulting in a decrease of the char breakage energy.At the late stage during the heating process,the char breakage energy increased with the increase of heating time.The power consumption coefficients CKof different chars were determined by a drum experiment,and then the char degradation behavior under different power consumptions was predicted.In addition,agasification experiment was conducted to determine the gasification activation energy（with CO_2）of lump coal heated for different time.The results show that the gasification activation energy increased greatly at the early stage during the heating process,which showed opposite change to the breakage energy of chars.Furthermore,the internal temperature and heat changes of the bonded coal briquette were calculated by using an unsteady heat conduction equation.The large difference between the surface and the center temperatures of coal and the large amount of heat absorption at the early stage during the heating process may have a negative effect on the breakage energy of chars.展开更多
文摘Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion.In the present work,experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal.Heat-affected coal(31%ash and 5300 kcal/kg GCV)collected from Jharia coalfield were blended with thermal coal(28%ash and 5650 kcal/kg GCV)in different ratios of 90:10,80:20,70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities.Burning characteristics of all the coals were carried out using TGA.Various combustion parameters such as ignition temperature,peak temperature,burnout temperature,ignition index,burnout index,combustion performance index,rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process.Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.
基金supported by National Natural Science Foundation of China(51604208,51574189)Talent Technology Fund of Xi′an University of Architecture and Technology(RC1610)
文摘The volume hypothesis,a theory about the energy scale of comminution,was adopted to analyze the degradation behavior of lump coal under different heating time.The breakage energy of chars was determined by a compression test,and the results show that the ultimate strength of chars decreased at the early stage during the heating process,resulting in a decrease of the char breakage energy.At the late stage during the heating process,the char breakage energy increased with the increase of heating time.The power consumption coefficients CKof different chars were determined by a drum experiment,and then the char degradation behavior under different power consumptions was predicted.In addition,agasification experiment was conducted to determine the gasification activation energy（with CO_2）of lump coal heated for different time.The results show that the gasification activation energy increased greatly at the early stage during the heating process,which showed opposite change to the breakage energy of chars.Furthermore,the internal temperature and heat changes of the bonded coal briquette were calculated by using an unsteady heat conduction equation.The large difference between the surface and the center temperatures of coal and the large amount of heat absorption at the early stage during the heating process may have a negative effect on the breakage energy of chars.
