High sulfur lignite samples collected from Giral mine was subjected to desulfurization using bacteria Burkholderia sp. GR 8–02 isolated from native lignite. A removal of 50.69% of total Sulfur (S_t) has been observed. The reduction in hydrogen and ash content was found up to 2.92% and 14.78%, respectively. In addition, relative carbon (up to 12.81%) and nitrogen (up to 34.52%) has also been increased. An increase in the relative concentration of volatile matter and fixed carbon (up to 19.47% & 3.29%) has been detected. In addition, the desulfurization of high sulfur lignite with Burkholderia sp. GR 8–02 increased the calorific value from 5.24% to 20.74%.

In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation using macerals and microlithtotypes as a tool. For these purposes a large number of samples were collected following the pillar sampling method and were subjected to detailed petrographic study. The petrographic observation shows that these coals are vitrinite rich followed by the liptinite and inertinite group of macerals. On microlithotype scale, these coals shows the dominance of the vitrite followed by clarite, vitrinertite and inertite. The concentration of liptite, clarodurite, duroclarite and vitrinertoliptite are insignificant. The vitrinite reflectance ranks the Karharbari coal as high volatile bituminous ‘C’ to high volatile ‘B’ bituminous. Coal petrography based depositional models suggest peat accumulation in forested telmatic swamp. Moreover, during the time of their evolution, there were alternate phases of oxic and anoxic moor conditions with good tissue preservation.

Present investigation entails the results of desulfurization of high sulfur Giral (Rajasthan-India) lignite with the help of Burkholderia sp. GR 8–02. Total sulfur varies from 3.73% to 7.91%, where inorganic sulfur is 2.17–3.82%, pyritic and Sulfate sulfur is 0.90–2.42% and 0.47–2.84%, respectively. Chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS) were used in order to understand desulfurization. Bacterial treatment caused a significant reduction in total sulfur content ranging from 23.59% to 37.55%. Organic sulfur removal ranges from 11.06% to 20.54% while pyritic and Sulfate sulfur removal vary from 10.40–43.39% and 50.89–96.97%, respectively. In addition to desulfurization of lignite, the reduction in the ash yield and the volatile matter was also observed whereas there was a relative increase in the fixed carbon and elemental carbon content. Further, an increase in the gross calorific value from 3189 kcal/kg to 3482 kcal/kg was noticed.

In the present study an attempt has been made to characterize the Gurha lignites employing petrographic and geochemical techniques on a large number of lignite samples. The data generated has been discussed to understand the hydrocarbon generation potential as well as the evolution of the paleomires of these lignites. The present investigation indicates that these lignites are mainly dominated by the huminite followed by inertinite and liptinites occurs in meager concentration. The huminite reflectance values rank the Gurha lignite as a low-rank B lignite. Petrographic result indicates these lignites are thermally immature in nature and comprised of Type-III kerogen and may generate only gas on maturation which is further supported by the rock-eval pyrolysis. The plots of rock eval data also indicates the same. The GI and TPI as well as GWI and VI values and the petrography-based facies critical models indicate that these lignites originated mostly under wet forest swamp condition. The microscopic constituents have also shown that these lignites are from herbaceous plants in wet forest swamp environment and ombrotrophic hydrological condition. The presences of framboidal pyrite in the study area infer the marine influence which also supported by the presence of high sulphur content.