385 / 2018-07-30 16:29:02

Investigation of the Relationship between Functional Groups Evolution and Combustion Kinetics of Microcrystalline Cellulose using in situ DRIFTS

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Direct combustion technology and mixed combustion technology are important ways of solid fuels utilization. Functional groups evolution characteristics have an important influence on the combustion mechanism because they directly affect the diffusion of oxygen on the surface of solid fuels. In this paper, microcrystalline cellulose was chosen as feedstock. The functional groups evolution characteristics were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and thermogravimetric (TG) analysis was also conducted to be compared. The relationship of combustion kinetics during the initial stage of combustion and situ functional group evolution characteristics were obtained. In situ DRIFTS and TG of cellulose were performed from 20℃ to 500℃ at different heating rates in different atmospheres. The results of in situ DRIFTS showed that most functional groups firstly decreased and then increased at approximately 300℃ with increasing temperature. C=O functional group generated and significantly increased during heating process. This can be attributed to the internal dehydration of cellulose on the surface layer and the formation of activated cellulose. Compared with the offline experiments (TG), it can be obtained that the activation energy become lower with the increase of the functional groups. This study demonstrated that the combustion kinetics can be predicted by the surface functional groups evolution of solid fuels, which provides a potential way for studying solid fuel combustion.