Fikret Kargi

Microbiological coal desulphurization

Abstract Sulphur compounds present in coal impose severe limitations on its utilization since sulphur-containing gases emitted into the atmosphere upon direct combustion of coal cause serious environmental pollution problems. Removal of sulphur compounds from coal by microbial action has many advantages over physical and chemical desulphurization methods. The potential use of various microorganisms for the removal of sulphur compounds from coal is presented. Environmental conditions and major process variables affecting the process performance are identified and their possible effects are discussed. Various process schemes for microbial desulphurization (MDS) of coal are suggested. It is concluded that microbial methods have a high potential in removing sulphur compounds from coal. However, more research and development work is needed in this field to overcome present technological problems.

Removal of organic sulphur from bituminous coal: Use of the thermophilic organism Sulfolobus acidocaldarius

It has been shown that part of the organic sulphur from inorganic-sulphur-free bituminous coal samples can be removed by the thermophilic, facultative autotrophic, sulphur oxidizing organism Sulfolobus acidocal-darius. Nearly 44% of initial organic sulphur was removed from 10% coal slurries at 70 °C in about four weeks. The organism also oxidized dibenzothiophene (a refractory cyclic organic sulphur compound present in coal) and released sulphate ions into the medium.