Agglomeration in fluidized bed gasification system is considered as a primary operational problem

especially for catalytic coal gasification process because alkali catalyst worsens sintering and slagging. The optimal condition from the experiments will ensure the operation of coal gasification below sintering temperature and make the fluidized bed gasifier operate normally. In this paper a self-made pressurized pressure-drop measuring device combining analysis of X-ray diffractometer (XRD) analyzer were used to study the effects of alkali catalyst addition

operation pressure and reaction atmosphere on sintering temperature of Wangjiata bituminous coal from Inner Mongolia

China. Sintering temperatures declined markedly after adding potassium carbonate catalyst. Sintering temperatures decreased with increasing pressure in the range of 0.1—3.5 MPa

and a more obvious decrease could be observed in the interval of higher pressure. This effect could be related to coal ash composition and addition of alkali catalyst. Operation pressure influenced sintering temperatures by affecting reaction rate and mineral transformation in coal ash

as observed from XRD patterns. Sintering temperatures measured in the reducing reaction atmosphere were lower than those in inert and oxidizing atmospheres

which could be related to different existence forms of Fe ions and K. The addition of water vapor lowered sintering temperature significantly. The presence of water vapor led to formation of low melting point materials

such as KOH

and K-bearing materials were easier to react with minerals of coal ash to produce low temperature eutectics in water vapor atmosphere

thus lowering sintering temperature.