Thermal performance analysis and experimental validation of primary chamber of plasma pyrolysis system during preheating stage using CFD analysis in ANSYS CFX. (1st August 2020) - Sharma, Deepak
Highlights: CFD preheating transient analysis for primary chamber of plasma pyrolysis system using ANSYS CFX. Radiation mode of heat transfer from plasma arc to chamber included. Plasma arc is modelled as source of heat. Simulation results have been compared with experimental results for different power inputs. Abstract: Plasma pyrolysis is emerging as a very attractive approach for safe disposal of bio-medical wastes worldwide. In this process, the plasma arc plays a vital role for achieving the desired high temperature of ~1000 °C in primary chamber before the waste is fed into this chamber and the waste is decomposed without generating any toxic molecules and by-products. This technology has been indigenously developed at the Facilitation Centre for Industrial Plasma Technologies (FCIPT), Institute for Plasma Research (IPR), having a capacity of processing around 50 kg biomedical waste per hour. The transfer of heat from plasma arc to inner volume of the primary chamber predominantly takes place through radiation and it is further aided by convective heat transfer by nitrogen gas flowing around the arc. Transient CFD (Computational fluid dynamics) simulation has been performed using the commercially available CFD tool ANSYS CFX to determine the temperature and its comparison with experiment. Currently only a preheating analysis without the introduction of waste or any chemical reaction has been performed. This would assist in designing a high capacity (200 kg/h or more) plasma pyrolysis system by validating the methodology and assumptions used in this study. The study has provided information on temperature distribution, heat loss, energy balance, etc. during the pre-heating stage of primary chamber. The CFD results are found to be within a comparable range (<20% for inner surface and <10% for outer surface) for most of the duration of the experiment. The reasons for deviation have also been discussed in the paper.