Influence of properties of bituminous binders on the strength of formed coke

Abstract

The role of different chemical characteristics (coking value, quinoline insolubles, elemental composition, β-resin, toluene solubles) of various coal tar- and petroleum-based bituminous binders, such as heavy fraction of HTC tar, processed LTC tar, pitch and asphalt as also the mixed binder in controllling the strength of formed coke made from char prepared from non-coking Chirimiri coal and coke breeze (prapared after carbonising Jharia coal), respectively, has been studied in some detail. The objective was to investigate as to whether and how the properties of these bituminous binders govern the strength of formed coke. It is found that these properties of the binders do play significantly important role in controlling the strength of formed coke both during curing and carbonisation. These parameters of the binders are found to be closely related with their atomic C/H ratios. Notwithstanding the varying composition of the binders of different origin-be they coal tar or petroleum based, the atomic C/H ratio seems to be the most important characteristics of the bituminous binders, upon which the strength of formed coke depends predominantly. This also holds true when mixed binders were used. The results show that at a C/H ratio of about 1, the strength of the briquettes either on curing or on carbonising remains almost similar and that strong cured briquettes can be produced by using a bituminous binder with a C/H ratio less than 1, whilst for obtaining strong carbonised briquettes, binders with C/H ratio greater than 1 are preferable.