Classification Of Shengli Lignite And The Study On Thermodynamics

Lignite is a complex organic mixture, its anisotropy has a large effect on thermalchemical reactivity of lignite. Enriching component of similar structure and nuture inlignite by certain method and studying its chemical properties, could make for knowing thenature properties of lignite. Shengli lignite (SL) was chosen as the sample and it wasclassificationed by the methods of ZnCl2density classification, maceral classification andinherent mineral matter removal, thus the coal was enriched in component of consistentstructure and nuture as far as possible. SL-d and the coal after classification were analyzedfundamentally by Proximate, ultimate analysis, SEM and FT-IR; The samples were alsotested by pyrolysis, combustion, chemisorption, temperature programming steam andcarbon dioxide gasification properties characterization; and the pyrolysis and combustionreaction of coal has on dynamics analysis.Experimental results show that, coal is mainly distributed in the range of gradeddensity of greater than1.5. Maximum weight loss rate of S1.2-1.3, S1.3-1.4in pyrolysis processis1.80,1.69%min-1respectively, are higher than other samples.While the maximumweight loss temperature of S1.2-1.3, S1.3-1.4are430,413℃respectively, are slightly lowerthan other samples. So these two coals possess better pyrolysis performance. Theignitability number of S1.2-1.3, S1.3-1.4is1.70,2.21(×104,%min-1℃-2), the comprehensiveindex of combustion is2.78,3.93(×107,%2min-2℃-3), so the coal samples in range of1.2-1.4g cm-3possess better combustion performance. In the temperature range of300-500℃, the combustion activation energy of S1.2-1.3, S1.3-1.4is48.4,45.0kJ mol-1respectively, are lower than other density samples. The maceral classification processindicates that two separable macerals exist in the lignite of shengli: arborescence andcompact shape samples.The surface morphology of arborescence and compact shapesamples have significant difference, and their appearance does not change with the particlesize within a certain range of particle size. The initial pyrolysis temperature, the maximumweight loss temperature of compact shape sample are274,400℃respectively, are lowerthan the arborescence sample corresponding296,445℃. While the maximum weight lossrate of the compact shape sample is1.30%min-1, is higher than the arborescence samplecorresponding1.23, so the pyrolysis performance of compact shape sample is superior to the arborescence sample. The ignitability number of the arborescence sample is0.683(×104,%min-1℃-2),1.31(×107,%2min-2℃-3), is higher than the compact shapesample corresponding0.466,0.850, so the combustion performance of the arborescencesample is superior to the compact shape sample.The exist of inherent mineral matter reduces the pyrolysis performance of lignite ofshengli and helps its CO2gasification and combustion; the ignitability number and thecomprehensive index of combustion of SL-HCl are lower than SL-d. When the oxygenconcentration is5%, the combustion activation energy is103.7kJ mol-1in the temperaturerange of320-355℃; when the oxygen concentration is80%, the combustion activationenergy reduces to90.8kJ mol-1. With the increasing of oxygen concentration, theignitability number of SL-HCl increases from0.288to0.451(×104,%min-1℃-2), and thecomprehensive index of combustion increases from0.380to0.899(×107,%2min-2℃-3).The increasing of oxygen concentration improves the combustion performance of SL-d andSL-HCl.