Dynamic Study On The Combustion Process Of Solid Fuels Based On Spectral Analysis

Combustion process of solid fuels involves with a series of complex physical and chemical reactions because of the complicate contents,which is a heterogeneous reaction system.A thorough understanding of combustion characteristics and the conversion path of combustion products is the basis for improving the efficiency of energy utilization and controlling the generation of pollutants.At high temperature,the combustion reaction of solid fuels is very fast.However,the existing combustion models still have some problems,such as limited application scope and difficulty in selecting empirical parameters.The experimental study of combustion characteristics and product formation is an important basis for developing and optimizing combustion models.The development of rapidly in-situ measurement technologis,wich are suitable for high temperature and complex environment,providing a new direction for the study of combustion process.Therefore,this paper is committed to applying optical technology to the dynamic analysis of combustion process of solid fuels.The experimental and theoretical investigation on the formation and release mechanism of pollutants was performed,including the air pollutant NO_x and alkali metals that affects the safe and efficient operation of combustion equipment.The existing combustion diagnostics and analysis method for the investigation and in-depth understanding of combustion characteristic are overviewed and the researches on the application of thermometry and componential analysis methods for particle solid fuel combustion process are summarized in the paper.According to these investigations,specific research directions are explained referring to the combination of the advanced measurement technology and the combustion characteristic research.On this basis,a multi-information-fusion experimental configuration for studying the spatial and temporal distribution characteristics of particle solid fuel combustion process was designed and constructed.Using optical technique for the analysis of flame from volatile combustion to char burning process of solid particles to investigate the combustion characteristics of different solid fuels.Observations on the influence of combustion atmosphere demonstrated the combustion mechanism.The experimental results and theoretical analysis were combined to reveal the generation and transformation path of products.In order to study the combustion process of solid fuels,the flame temperature and morphology,products information of the whole combustion process were obtained by various measurement methods.The ignition and combustion characteristics of solid fuel with different components was investigated by image and flame emission spectrum analysis.Using the emission spectrum of the combustion products to realize the observation of the whole process of solid fuel particle ignition and combustion.Comparing the morphological characteristics of flame structure and the spatial and temporal distribution of alkalis under different atmosphere to establish relevance between combustion phases and spectral characteristics.The study of the solid fuel ignition characteristics and alkalis release during combustion also focused on the influence of factors such as volatile contents and atmosphere.On the basis of fully understanding on the solid fuel combustion process,an in-situ online analysis technique,Laser Induced Breakdown Spectroscopy(LIBS)was introduced to the study of solid fuel combustion process to obtained more information of products.The corresponding relationship between residual laser energy and flame temperature was studied and the results were utilized to achieve the synchronous measurement of flame temperature and components.Combined with image analysis,the variation of flame temperature and morphology during the burning process was used to distinguish the combustion phase.Products generated in different combustion phase under various atmosphere were investigated to reveal the devotilization mechanism,as well as the ignition and combustion characteristics of different solid fuels.By analyzing the combustion process of single particle fuel under different atmospheres,as well as the conversion of related products,the correlation between spectral characteristics and NO_xgeneration process were studied.Temporal and spatial variation of related products also reveals the mechanisms of NO_x formation and reduction.In this work,a series of experimental and theoretical analysis methods for the study of solid fuel combustion process are put forward,which provides practical basis for developing models of volatile release and ignition of particle fuels,as well as deepening the understanding of combustion mechanism.