The existing gasification technologies can hardly treat the coal like washing middlings that has caking index above 10 and also ash content

as high as above 40% (mass). Coal industry

such as coking industry

however

has great need to gasify this kind of coal for realizing its value-added utilization. Institute of Process Engineering (IPE)

Chinese Academy of Sciences (CAS) proposed the jetting pre-oxidation fluidized bed gasification (JPFBG) to treat such a kind of coal. Coal particles are fed into the dilute zone of a fluidized bed reactor with a gas jet containing oxygen to implement the destruction of coal's caking property. The jetting feed also strengthens gas-solids contact and accelerates gasification reaction. This study was devoted to characterizing the destruction of coal caking property via jetting feed of coal in a bench-scale fluidized bed with jetting pre-oxidation for a kind of powder coal with caking index of about 20. The tested parameters included equivalence ratio (ER) and O2 concentration (CO2) in the jetting gas and reaction temperature (T). The results were analyzed in terms of time-series temperature in the reactor

time-series product gas composition and char characteristics given by SEM and FTIR analyses and gasification reactivity. The operational conditions for fully destroying the caking property of the tested coal were T>950℃，CO2=21% (vol) and ER>0.1. In this case the temperature in the feeding zone of the reactor was steady and the H2 and CO concentrations in the product gas were very low. Otherwise (caking occurred)

time-series temperature tended to decrease and the H2 and CO concentrations of product gas increased. Some adherent matters were identified on the surface of the char if caking occurred

whereas most of the functional groups disappeared from the char in the operation without occurrence of caking.