Hans-Werner Schröder

A new approach for processing and agglomeration of low-rank coals for material usage

The material usage of low-rank coal offers a high potential regarding the increasing in added value. The production of coke from a wide span of low-rank coals may be a promising perspective. Since low-rank coals do not exhibit any baking properties they need to be briquetted before pyrolysis to get a lump coke. Using two brown coals the influence of processing parameters and briquetting parameters were investigated. The comprehensive investigations showed that, besides the well-known relations between briquetting parameters, the changing of processing from conventional comminution of the coal to new processing leads to increasing strength of briquettes and coke. Due to the intense novel comminution in the flat die press as well as in the mixer the binding between the particles may be increased and the shrinkage behaviour of the coals was improved during pyrolysis so that coke strength could even exceed the briquette strength. The new developed pyrolysis briquettes and the lump coke show high mechanical strength and only small amounts of fines due to the mechanical stress, leading to high yield in the coarse coke fraction.

Briquetting of Coal Fines for Use in Smelting Reduction Processes

COREX®/FINEX® smelting reduction processes require lumpy coal for stable operation. The screened-off coal fines must be briquetted by means of binders to be utilizable for the COREX®/FINEX® processes. Optimal binder types, their amount, and briquetting conditions are identified by systematic experimental analyses. Experimental work is based on a critical review of literature to get knowledge about the theoretical background of hard coal briquetting, established hard coal briquetting technologies, and typical tests for metallurgical carbon carriers. Binder briquetting of hard coal is known to produce briquettes for heating. Compared to metallurgical use, briquettes quality and process behavior requirements are differing, but basic mechanisms like coal-binder-interaction are similar.ZusammenfassungFür einen stabilen Betrieb benötigt der COREX®/FINEX® Schmelzreduktionsprozess stückige nicht-/schwachbackende Steinkohlen. Um Kohleabrieb, der vor dem Einsatz abgesiebt wird, für den Prozess nutzbar zu machen, muss dieser mit Hilfe von Bindemitteln brikettiert werden. In systematischen experimentellen Untersuchungen werden potentielle Bindemittelarten/Bindemittelmengen und geeignete Brikettierbedingungen ermittelt. Ausgangspunkte sind eine kritische Bewertung der etablierten Verfahren, die Analyse der theoretischen Grundlagen sowie die Diskussion vorhandener Bewertungsmethoden. Die Brikettierung von Steinkohle mit Bindemitteln wurde bisher hauptsächlich zur Herstellung von Hausbrandbriketts angewendet. Dabei unterscheiden sich die Anforderungen an Briketts für metallurgische Einsatzzwecke, allerdings sind die Grundmechanismen wie die Wechselwirkungen zwischen Kohle und Bindemittel ähnlich.