The effects of operational parameters on the transport phenomena in COREX melter-gasifier

Using a computational code developed for simulating the COREX melter-gasifi er, the effects of operational parameters on the transport phenomena in the melter-gasifier were studied. The parameters studied were the bed height, C/O ratio, operating pressure and steam injection ratio. When the bed heigh t was increased, the temperature near the combustion zone also increased du e to there being sufficient heat exchange between the gas and solid phase. However, the freeboard zone temperature remained constant due to the increa sed residence time for heat exchange. Operational pressures affect the rate of tar in the coal. However, the extent of the change in the evolved tar a s a function of pressure did not vary severely. The variation in the C/O ra tio affected the hearing rate of coal followed by a drastic change in the h eat and mass transfer of solid and gas phases. The combustion zone and the freeboard zone temperature were changed largely by variations in the C/O ra tio. The C/O ratio also changed the evolution rate of the coal by the chang es in heating rate. From these considerations, the C/O ratio should be care fully controlled for the stable operation. The effects of steam injection i nto the melter-gasifier were also studied. Up to a steam injection rate of 30 %, the temperature of the combustion zone increased. Steam injection als o affected the effluent composition of the gas phase. When the steam inject ion ratio was increased, the CO/CO2 ratio was decreased while H-2/H2O ratio was remained unchanged.