Minimum TI4085D interlock setpoint at 1.0 GPM sludge-only feed rate and 14,000 ppm TOC

摘要

DWPF-Engineering requested that SRTC determine the minimum indicated melter vapor space temperature that must be maintained in order to minimize the potential for off-gas flammability during a steady sludge-only feeding operation at 1.0 GPM containing 14,000 ppm total organic carbon. The detailed scope of this request is described in the technical task request, HLW-DWPF-TTR-960092 (DWPT Activity No. DWPT-96-0065). In response to this request, a dynamic simulation study was conducted in which the concentration of flammable gases was tracked throughout the course of a simulated 3X off-gas surge using the melter off-gas (MOG) dynamics model. The results of simulation showed that as long as the melter vapor space temperature as indicated on TI4085D is kept at 570 degrees C or higher, the peak concentration of combustible gases in the melter off-gas system is not likely to exceed 60 percent of the lower flammability limit (LFL). The minimum TI4085D of 570 degrees C is valid only when the air purges to FIC3221A and FIC3221B are maintained at or above 850 and 250 lb/hr, respectively. All the key bases and assumptions along with the input data used in the simulation are described in the attached E-7 calculation note.