A new technological classification of low-rank coal on the basis of Polish deposits

Abstract

Proposed technological classification of low-rank coal has two stages. First part, presented in graphic form, sets the rank of coal, grade of coal and its petrographic character. In order to assess the rank and distinguish various subcategories of low-rank coal, random reflectance of ulminite B/collotelinite has been applied. Simplified petrographic composition of humic coal allowed – on the basis of the content of macerals from huminite group (vitrinite – for bright brown coal) – to distinguish subcategories of low rank coal. Ash content of coal recalculated to dry basis determines – in proposed first stage of the classification – the grade of coal. Second stage of technological classification is presented as codification system, while it distinguishes following types of low rank coal: energetic coal (type 21), coal for gasification (type 22) as well as coal for liquefaction (type 23). Coal types are defined through chemical, technological and petrographic criteria. Every single type of low-rank coal has its own unique technological code, consisting of main and supplementary parameters. Main code allows to determine the possibility of its use in certain technologies, while supplementary code precisely characterizes the parameters important for those applications. Technological quality of tested coal has been presented with use of code number, which digits have been set on the basis of division into classes within tested parameters.