DBPapers
DOI: 10.5593/sgem2012/s03.v1058

STUDY OF LIGNITE QUALITY PARAMETERS DURING STORAGE

M. CRUCERU, L. POPESCU, B. DIACONU, C. RACOCEANU, C. POPESCU
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 1, 835 - 842 pp

ABSTRACT

The auto-ignition is a specific process of lignite and brown coal due to the properties of
these coals to fix atmospheric oxygen by adsorption. The oxygen fixation leads to slow
autooxidation of combustible material, releasing heat.
Due to low thermal conductivity, heat generated causes a slow increase in temperature
leading to auto-ignition of coal. For each type of coal, there is the characteristic
temperature at which the process of physicochemical fixing of oxygen (adsorption) is
translated into a chemical fixation process (oxidation).
The danger of ignition is greater as the coal is richer in oxygen and volatile matter.
The coal autooxidation in the deposit leads to worsening of coal characteristics (density,
elemental chemical composition, volatile matter content, calorific value) and decreases
their coking capacity.
The auto-ignition usually occurs after 1.5 ... 3 months of storage. The auto-ignition is
favored by sun radiation, grain variety, presence of foreign bodies, air and moisture.
The paper presents a study on coal temperature and quality parameters during storage
according to storage time and environment parameters.

Keywords: Lignite, stockpile, spontaneous combustion, temperature