Mechanism of carbon deposits formed during plasma pyrolysis of coal for acetylene production

The carbon deposits were formed on the reactor wall during plasma pyrolysis of Xinjiang candle coal in the 2 MW plasma pyrolysis pilot-plant.To make for reducing or avoiding their formation during the experiment,these carbon deposits were studied by the scanning electronic microscope(SEM) and X-ray diffraction(XRD) methods.The result shows that the carbon deposits located at different parts in the reactor present a distinguishing microscopic pattern,and their formation mechanism is deduced.The wall-side carbon deposits of the mixing sector are formed through copper catalysis,while wall-side carbon deposits of the first and second reaction sectors are composed of coal powder fragments.The gas-side carbon deposits accordingly are formed by gas-solid,gas-solid and tars Absorption/dehydrogenation reaction respectively.The graphitization degree of the carbon deposits increases downwards,which depends on their own graphitization property.