This study investigated the in situ char reactivity in CO_2 of a Victorian lignite in athermogravimetric analyser and a fluidised-bed reactor at 900°C. The raw Loy Yang coal(“raw coal”), and a NaCl-loaded coal (“NaCl coal”), which was prepared by the physicalimpregnation of NaCl into the raw coal, were studied. In the thermogravimetric analyser, thereactivity of the char from the NaCl coal was much higher than that from the raw coal, dueapparently to the catalytic effect of the loaded NaCl. However, such catalytic effect of NaClwas not observed in the fluidised-bed reactor. The data showed that the char reactivity wasinfluenced by two interacting factors, i.e., the loading of NaCl and the char -formingconditions. The NaCl loaded into the raw coal was only a potential to increase the catalystconcentration of the char after pyrolysis. The actual extent of such catalytic effect wasstrongly influenced by the char-forming conditions, including the hydrodynamics and heatingrate in the reactor. A large proportion of the loaded NaCl was retained in thethermogravimetric analyser, acting as good catalyst in subsequent gasification. However, theloaded NaCl was virtually all volatilised during pyrolysis in the fluidised-bed reactor, leavingno catalytic effect during char gasification.
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