2000 年 40 巻 11 号 p. 1073-1079
Using a computational code developed for simulating the COREX melter–gasifier, 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 height was increased, the temperature near the combustion zone also increased due to there being sufficient heat exchange between the gas and solid phase. However, the freeboard zone temperature remained constant due to the increased 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 as a function of pressure did not vary severely. The variation in the C/O ratio affected the heating rate of coal followed by a drastic change in the heat 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 ratio. The C/O ratio also changed the evolution rate of the coal by the changes in heating rate. From these considerations, the C/O ratio should be carefully controlled for the stable operation. The effects of steam injection into the melter–gasifier were also studied. Up to a steam injection rate of 30 %, the temperature of the combustion zone increased. Steam injection also affected the effluent composition of the gas phase. When the steam injection ratio was increased, the CO/CO2 ratio was decreased while H2/H2O ratio was remained unchanged.
