Research Projects

Coal plays a pivotal role in the Indian energy scenario. Underground/ in situ coal gasification (UCG) technology can be used in India to produce cleaner energy using domestic coal resources, including currently unmineable deposits, at competitive costs and with minimum damage to the environment. The need for undertaking pilot and commercial operations for UCG has been amply recognized by the Ministry of Coal, Government of India to carve out 7 lignite and 8 coal blocks for UCG trials. UCG is defined as a thermo-chemical process, and is achieved through a set of injection and production wells by injecting oxidants, gasifying the coal in situ and bringing the product synthetic gas (syngas) to the surface. The rate of the gasification reactions is influenced by the coal composition, thermal maturity, reactive surface area, char morphology (structure) etc. Hence, gasification kinetics of Indian coals in the perspective of in situ gasification need to be thoroughly investigated with respect to coal composition, hydrology and geology of the terrain. Petrographic study, elemental analysis and thermogravimetric analysis (TGA) will be carried to understand gasification kinetics. The data so generated on coal composition, maturity, calorific value, char morphology, reactive surface area, reaction kinetics etc. will be used as input to simulate the in situ gasification process and optimize the PT-X conditions to obtain sustained flow of quality gas and to monitor the cavity growth to limit ground movement. The study will help in developing best practice guideline for planning UCG projects for various geologic and hydrologic conditions, to design the UCG gasifier, to get the desired syngas composition, and to scale up for the UCG field trials. However, there is a probability of contamination of groundwater in the surrounding aquifers with the byproducts of UCG process which include complex organics like phenolics, benzene toluene xylene (BTX), poly aromatic hydrocarbons (PAHs), other gas phase contaminants like ammonia, carbon compounds. When the escaping gas stream comes in contact with the surrounding aquifers, it leads to a gas-liquid reaction that causes groundwater contamination. Some ionic species like Ca²+, Na+, K+, SO₄²-, HCO³- present in the ash may leach out to the adjoining groundwater in varying proportions. The rate of leaching process and the gas-liquid reaction is a function of pH, temperature, reaction products and intermediates, composition of the surrounding strata etc. The study aims at developing methodologies to identify possible contaminants, the process of contamination and strategies to reduce it through simulation studies. Broadly, the objective of the present investigation is to understand gasification kinetics of Indian coals in simulated in situ conditions to assess gas quality, to optimize the gas production and cavity growth, and to evaluate the sources and process of possible groundwater contamination.

Coal, thermogravimetry, char, fractals, simulation, reactive transport