| Liptobiolith coal is a special and scarce coal with the basic characteristics of high content of exinite,which lacks systematic research at present.Based on the deep analysis of the chemical properties,coal petrology characteristics,solvent extraction conditions and product characteristics of liptobiolith coal in Dahebian,Guizhou,this article aimed to clarify the dissociation laws of the three macerals and on this basis,the enrichment density range ofeach maceral was obtained,the solvent extraction scheme suitable for the coal was screened out,part of the structure and composition information of liptobiolith coal were grasped,combined with the characteristics of extracts with different compositions of different maceral,which provides theoretical guidance for the directional conversion and utilization of liptobiolith coal.The analysis of basic properties of liptobiolith coal in Dahebian,Guizhou showed that the coal was characterized by high volatility,high hydrogen,and high sulfur;the calorific value of raw coal was 21.702 MJ/kg;at 464?,the weight loss rate was the largest,the ignition characteristic temperature of the coal was 408?;kaolinite and quartz was the main minerals in coal.The content of vitrinite,inertinite and exinite of raw coal was 40.91%,29.97%and 23.01%,respectively,and the barknite was the main component of exinite;the vitrinite was often connected with the exinite and the inertinite,the latter two were less embedded in each other;the vitrinite was mainly distributed in the finer grade,the inertinite and the exinite was mainly distributed in the coarser grade;the dissociation degree of the macerals gradually increased with the increase of the degree of fragmentation,and the disintegration effect of the crushing operation on the vitrinite and the inertinite was more obvious;the best dissociation particle size of the three macerals was 0.125 mm-0.074 mm;density gradient centrifugation experiment showed that the optimal separation densities of the exinite,vitrinite and inertinite corresponded to-1.15 g.cm-3,1.27-1.29 g.cm-3,1.33-1.35 g.cm-3 density grades,and obtained sorting products with the content of 47.20%,81.32%,72.12%,respectively;the use of ultrasonic aids could disperse fine-grained materials effectively and enhanced the density effect,thereby increased the content of the exinite by 3.02 percentage points.Ethylenediamine,dimethylformamide,N-methylpyrrolidone/carbon disulfide(V/V 1:1)were the good extraction solvents for this liptobiolith coal,and the optimal extraction rates were 25.12%,29.86%,and 31.27%,respectively;the optimal extraction schemes of the three solvents were:particle size-0.045 mm,temperature 45?;time 6 h;particle size-0.045 mm,temperature 35?,Time 4 h;particle size-0.125 mm,temperature 45?,time 6 h.Through the analysis of the extraction products of raw coal,it was found that the solvent extraction technology could effectively remove the ash in the coal;the raw coal was mainly dominated by fat structure,and the aromatic structure was relatively stable;solvent extraction will change the surface morphology of the coal,and as the extraction rate increased,the pore structure in the coal becomed more obvious;the extracts were mainly straight-chain alkanes,C13-C34 were almost continuously distributed,and included alcohols,esters,and ketones with abundant oxygen-containing functional groups,most of the ketones contained N-containing heteroatoms.When extracting coal samples composed of different macerals,the results showed that the solvent extraction products were still mainly alkanes,but the proportion of alkanes was related to the content of each maceral,the extracts of coal sample rich in exinite had the highest alkane content;the extracts of coal sample rich in vitrinite contained more oxygen-containing functional groups,mostly in the form of esters,carboxylic acids,alcohols,etc;for coal sample rich in inertinite,the aromatization phenomenon was the most significant in extracts,and many extracts have aromatic ring structures. |
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