Experimental Study On The Relationship Betweem Characteristics And Reactivity Of Low Rank Coal

The application of low rank semi-coke, a product of low rank coal upgrading,seems to be of good prospects for the application, and it is a worthy to research andstudy. With pyrolysis processing, not only tar can be got, but also the low rank coaltransportation costs can be reduced, and the product is very suitable for coal waterslurry gasification, it is necessary to develop an excellent low rank coal pyrolysistechnology.In this paper, two groups of low rank semi-coke were made by using a fixed bedreactor with two coal from Xinjiang, Zhundong coal and Kuangou coal. They arepyrolysed in different pyrolysis temperatures (450℃,550℃,650℃), duringdifferent residence time (10min,15min,20min,25min). Two groups of semi-coke werestudied with physicochemical experiments, including volatile analysis experiment,surface area and pore structure characteristics experiment with adsorption method andmercury porosimetry method, crystal structure analysis with using X ray. Also twogroups of semi coke thermo-gravimetric experiments were conducted and air oxidationreaction was carried out at500℃, in order to get the reactivity of two groups of semicoke. Low rank coal physicochemical properties and reactivity are discussed in relationto the factors,.With pyrolysis temperature higher and pyrolysis residence time longer, there willbe great changes in the physicochemical properties of two groups of low rank semi-coke.The large pore surface area will decrease with the pyrolysis intensity ascension, but themedium pore and micro-pore surface area will increase with pyrolysis intensityascension. In the process of pyrolysis, macro-porous gradually collapse, disappear.While medium pore and micro-pore greatly increased. Two kinds of micro array charorientation is poor, but the crystalline lamellar stacking height increases with pyrolysisintensity ascension. The reactivity of semi coke decreased with pyrolysis intensityascension. Reducing of volatile and increasing of microcrystalline structure are the mainreasons for their reactivity decreased.