DEVELOPMENT AND PRACTICAL TESTS OF INSULATING/COOLING CAPSULE WITH SENSOR FOR IN-SITU MEASUREMENTS OF CO CONCENTRATIONS ON MOVING GRATES IN MSWI

摘要

MSW incineration consists of combustion of heterogeneous waste on a moving grate that transports and mixes the waste during the combustion process. The grate combustion process involves drying, devolatilization, gasification/combustion and char burn-out. Also, gasification and pyrolysis are subsets of combustion. Mathematical modeling of combustion on the grate requires the determination of the flow field and concentrations of gaseous species in a reacting and moving bed, taking into account various heat transfer mechanisms. Development of an accurate mathematical model of the incineration process is limited by the lack of measured data for validation. Requirements for specific (in-situ) data essential for the development of an incinerator burning bed model and a better understanding of the grate combustion process prompted accurate measurement of concentrations of selected gases within a moving, burning bed of solid waste.For this purpose a special capsule has been designed and developed originally by Sheffield University Waste Incineration Centre. In addition to insulating refractory ceramic fibers and materials with phase change properties, temperature sensors, small gas pump and internal electronics, the modified capsule also contains the electrochemical sensor for CO measurements.This unique self-contained and mechanically/thermally protected probe, consisting of measuring and recording electronic components, was able to withstand temperatures over 1000 °C for a period longer than two hours. The measurement technique differs from all conventional methods. The capsule can be introduced into the incinerator together with the waste and hence experience the same conditions on the grate as the waste material. This novel device proved to be convenient for in-situ measurements in moving grate incineration.