EMISSION OF GASEOUS POLLUTANTS DURING STORAGE OF COALS IN UTILITIES

Israel uses coal as the main source of electricity in utilities (~60% in 2012, 13 M tons of coal). As there are no coal sources in Israel- all the coals are imported via large cargo ships. Around 2 million tons are held annually in 2 storage facilities.

Self-heating of the coal piles due to LTO (Low Temperature atmospheric Oxidation) causes maintenance problems in the storage facilities owned by the Israel Electric Corporation. These problems occur because bituminous coal in contact with atmospheric oxygen undergoes autocatalytic heating as a result of the exothermic oxidation of coal by atmospheric oxygen. In addition to heat generation, these reactions also produce gaseous pollutants such as carbon dioxide, carbon monoxide, low molecular weight organic molecules (C1-5) and molecular hydrogen.

In extreme cases the heat generated is sufficient to cause fire eruptions. A recent two year study has shown that the self-heating processes also involve emissions of toxic and flammable/explosive gases such as methane CH₄, carbon monoxide CO and molecular hydrogen H_2. Also, coal held under these conditions shows a significant reduction in calorific value. The mechanism of these processes, measures which can taken towards deterring the self-heating and fire eruptions, and possible methods of reduction of these emissions will be discussed.