Study On Solvent Extraction Of Intermediate Bitumen For Carbon Fibers

Spinnable pitch is the raw material of high performance material carbon fibers.But the continuous production of spinanable pitch by solvent extraction using coal asraw material has not been reported. In the production of spinanable pitch, theextraction of bitumen is very important. In this paper the extraction of bitumen usingcoal as raw material and tetrahydrofuran as solvent was studied. The effects ofextraction conditions on extraction rate were investigated and the better extractionconditions were obtained. Under these conditions the extraction rate of bitumen was15.1%. The content and structures of bitumen were confirmed by GC-MS.The influences of coal source, coal particle size, extraction methods, extractionsolvents, extraction temperature, extraction pressure and time on the extraction rate ofbitumen were studied. The better extraction conditions were as follows: particle sizebetween0.5～3mm, extraction temperature between110℃～150℃, extractionpressure as2.0MPa, extraction time as6h. Under these conditions the extraction ratewas between14～15%. On the basis of single factor tests the effects of extractiontemperature, extraction pressure and time were researched using orthogonalmethodology. The better extraction conditions were as follows: extraction temperature140℃, extraction pressure2.2MPa, extraction time6h. Under these conditions theextraction rate was15.1%. The experimental results were confirmed by pilot-scaletest.