Development of coal petrography applied in technical processes at the Bergbau-Forschung/DMT during the last 50 years

The paper deals with the activities of the Bergbau-Forschung Coal Petrography Laboratory in Essen (Germany), which, under the influence of Marie-Therese Mackowsky, developed into a stronghold of the industrial application of coal petrology. In 1979, the formerly independent Section for Mineralogy and Petrology was merged with the Chemistry Section. This synergy has widened the research limits and resulted in higher efficiency of projects being carried out within both units. Since 1990, after transforming Bergbau-Forschung into DMT GmbH, a worldwide competition within hard coal and hard coal-based coke markets, together with the switch of the industry towards alternative energy sources, have significantly lowered the importance of the domestic coal mining industry. This in turn resulted in reduction of coal research programs. However, it is stressed that, in spite of transformations of the applied coal petrology experienced during the past 50 years, some achievements are still as applicable as ever. Among them, the method of predicting coke strength using maceral analysis and coal types, published by Mackowsky and Simonis [Mackowsky, M.-Th., Simonis, W., 1969. Die Kennzeichnung von Kokskohlen fur die mathematische Beschreibung der Hochtemperaturverkokung im Horizontalkammerofen bei Schuttbetrieb durch Ergebnisse mikroskopischer Analysen. Gluckauf-Forschungshefte 30, 25-27], is still in use today. The second part of this paper presents some examples of coal petrography applications, which are still important in carbonization processes. Mackowsky discovered that the pyrolytic components were influencing the coke homogeneity in coke ovens and affected coke quality parameters such as CRI and CSR. These highly graphitic layers and lenses prevent gasification of the inner zones of coke lumps, thus lowering the reactivity of metallurgical coke. Moreover, it also seems possible to predict wall load and maximum internal gas pressure as to prevent coke ovens from damage. Mathematic equations developed especially for the selection of coking coals and evaluation of coal blends for carbonization are also based on petrographic analyses, together with other factors such as bulk density and chamber width of the coke oven. (author)