Abstract
Tar coking might lead a serious trouble in the coal gasification plant, especially when the gasification temperatures are relatively low. Fluidized-ed heat exchanger has a good potential not only to prevent such a coking trouble but to recover heat from a hot gas leaving the gasifier. In this parer, effects of bed temperature and bed height on tar capture were investigated using an apparatus with 0.208m in diameter and 1.4m in height. The amount of accumulated coke on solid in fluidized-bed heat exchanger did not very significantly at temperatures ranging 392 to 554 t . However, at a temperature as low as 427 t, condensed tar did not decompose rapidly and a small amount of liquid tar was expected to appear on the fluidized solids, resulting agglomeration and unstable operation of the fluidized-bed heat exchanger.
At temperatures of 447°C or higher, fluidzed-bed heat exchanger could be operated steadily without agglomeration of the solids. The bed height of the fluidized-bed heat exchanger affected strongly the amount of tar removed through the bed.
