Pseudo-component Method For Characteration Of Thermochemical Conversion Of Combustible Solid Waste

The treatment of combustible solid waste?CSW?is a critical issue around the world.Thermochemical conversion is regarded as one of promising waste-to-energy?WTE?technologies.However,it's a huge effort to identify CSW's properties relevant to thermochemical conversion with enumeration method due to the variety of solid waste and complexity of their thermochemical conversion.Thus new and simplified methods are needed to characterize the thermochemical conversion of CSW.A pseudo-component method to characterize thermochemical conversion of CSW was proposed.Each type of CSW can be represented by model components in terms of mass coefficients which are obtained from a benchmark test.Then its thermochemical conversion characteristics can be calculated based on the mass coefficients and the characteristics of model components.Here work model components as a liaison between CSW and their thermochemical characteristics,which is a convenient method for characteristic prediction.Nine types of model components including cellulose,hemicellulose,lignin,starch,PE,PVC,PP,PS and PET,were selected based on quantitative and qualitative analysis of CSW in China.TGA was chosen as the benchmark test platform.All materials,including model components and CSW,were tested in N₂ atmosphere at a heating rate of 10?/min.The TG curves of model components were used to fit the curves of different types of CSW.Multiple linear regression method was adopted to acquire the mass coefficients.Grey relation grade was chosen as the precision evaluation criterion.The fitting precision was satisfactory while the average grey relation grade was higher than 0.97.Thermochemical conversion characteristics of CSW were predicted based on the coefficients acquired with multiple linear regression method and the characteristic data of model components.Prediction error was smaller than 5%for volatiles and 10%for gross heating value.The average grey relation grade between experimental results and predicted values was higher than 0.96 for all conversion process,including combusiton in air,gasfication in CO₂ on TGA and fast prolysis on a self-built Macro-TGA,which is a fixed bed with a balance.The mixing effects of nine model components were also studied on Macro-TGA.A distortion function was defined to quantitatively describe the mixing effects.A model was proposed to predict the thermochemical conversion characteristics of model component mixtures.Further more,conversion characteristics of CSW were also predicted through combination of that model and the mass coefficients of CSW.The average grey relation grade between experimental results and predicted values was higher than 0.97 for all mixtures of CSW studied.In summary,a novel pseudo-component method to characterize thermochemical conversion process of CSW was studied and relationships between CSW and model components were established.A calculation model was built to predict the thermochemical conversion characteristics of CSW mass cofficients and the data of model components.These efforts provided a new perspective for CSW study and a tool for process model building and engineering design.