Remote start-up of Joule Heated Ceramic Melter. Optimization of design parameters based on experimental and numerical investigations

In this research work, experimental studies on remote start-up of Joule Heated Ceramic Melter (JHCM) used for vitrification of radioactive liquid waste (RLW) were carried out. Numerical simulations were performed to understand the mode of heat transfer and improve the energy efficiency of JHCM during start-up. Preformed glass frit used for vitrification, is heated using Silicon–Carbide (SiC) resistance heaters installed in plenum region of the JHCM. Experiments were carried out to understand the heat transfer phenomena during the start-up of an industrial scale JHCM. The temperature was monitored at nine different locations to estimate heat losses from the melter, and based on this data, energy apportionment of the start-up heating was carried out. Different parameters that affect the efficiency of the start-up heating are identified and the effect of these parameters on the efficiency of the start-up heating is quantified. The effect of change in the geometry of the prefabricated slot in the refractory on the overall thermal performance of the melter is estimated. The results show that by deploying a circular geometry in the prefabricated slots of the refractory, the heat flux, heating rate and thermal efficiency of the melter can be increased by 44%, 10.4%, and 35%, respectively. (author)