Coal & Gas Technology Division
Coal R&D had occupied centre stage in the institute's R&D profile since the inception of this institute. After renaming as 'Regional Research laboratory, the institute started with focused R&D work on 'Coal Utilization' and recorded voluminous professional expertise in the area of process development for rational utilization of the locally available low-grade coals. Over a period of time, the Coal Division developed technologies for the Low Temperature Carbonization of Coal (LTC),Coal-tar Distillation, Briquetting of Coal-char fines to Domestic coke, Moving Bed Pressure Gasification of Coals for Power Generation, Atmospheric Fluid Bed Gasification for Fuel Gas production, Hydrogenation of Coal-tar hydrogenation to Middle Distillates, Benzene to Cyclohexane, Hydro-cracking of Coal-tar to Paraffins / Naphthalenes, Extraction of Tar-acids and Tar-bases, Extraction of phenols from Ammoniacal liquor, Shaped Industrial Fuel, Formed Coke from Coke Breeze, Biomass Briquettes from Coir-pith, Saw dust etc.,
Impregnating Pitch from High Temperature Coal-tar, Unsymmetric Di-Methyl Hydrazine (UDMH) for Space Applications, Pine Char Carbonization for Rubber Industries, Activated Carbon from Coconut Shells, 3, 5-dimethyl phenol from acetone, 2,3,6-Trimethyl phenol from m-cresol alkylation with methanol, Hot Gas Clean up for dust removal & desulphurization of coal-derived fuel gas for IGCC application, etc. in the past, some of which could even be transferred successfully to the Industry.
Development of Eco-friendly Processes for commercial utilization of abundantly available low-grade Indian non-caking Coals being the primary goal of the division, work on High Pressure Gasification of Low-grade Indian Coals in Dry-bottom Moving Bed Reactors was initiated in as early as 1966. It culminated in the preparation of a Techno-Economic Feasibility Report (TEFR) for a nominal 600MW IGCC power plant that compared four different IGCC processes including the IICT's Moving Bed Gasification based IGCC with NTPC's Conventional Thermal Power Plant of same capacity in 1992. As a follow up, Process development for High/Medium temperature Multi-contaminant Clean up of Coal-derived Fuel Gases with an emphasis on Low Energy-intensive Methods for Gas Separations was taken up.
Specialist groups existed that worked on applied R &D for technology adaptation, Indigenous Process Development as well as Coal S&T Services for Analysis of Coals for Resource Quality Assessment. Our Sponsors & Clientele included UNDP; Ministry of Coal; Ministry of Power; Ministry of Non-conventional Energy Sources; Singareni Collieries Co. Ltd., Kothagudem; Corporate R&D division of Bharat Heavy Electrical Ltd., [BHEL(R&D)], Hyderabad; The Energy & Resources Institute (TERI), New Delhi, etc.
LTC process for producing domestic coke was perhaps, one of the first and the largest successful effort in this direction that could be commercialized. A 900 tonnes coal per day Commercial LTC plant based on the IICT technology went in to operation as early as by 1978 at the Coal Chemicals Complex of the Singareni Collieries Co., Ltd., Ramakrishnapuram, AP, producing the 'SICCO Coke®' and operated uninterrupted for over three decades till it was recently shut down in the late-Nineties due to growing problems in the marketability of the product. Extensive work was carried out on various briquetting aspects including the development of different binders, led to transfer of technology to small, medium and large-scale industry alike that included commercial use of our technology in the Coal chemicals Complex of SCCL.
A lt/hr pilot plant based on the moving bed gasification was installed and operated for gasifying low-grade Indian coals during 1983-90. An initiative was taken as early as in the mid-sixties got fulfillment through the UNDP-assisted effort on establishment of the 24 tpd Pilot Plant for pressure gasification of coal and an Elaborate Experimental Programme that included parametric optimization studies and testing of six different low-grade Indian coals and a lignite, Special studies on development of a Mathematical Model and its validation, Elucidation of Gasification eaction Kinetics through studies on Coal Reactivity in a Thermo- Gravimetric Analyzer (TGA), Measurement of Axial Temperature Profile in the Fuel Bed, Residence Time Distribution for flow of solids down the reactor, Scale-up studies for application in power generation through Integrated Gasification Combined Cycle (IGCC), etc. The objective was to carry out gasification tests to collect process design data from specific candidate coal samples for different end-uses of the product gas including the development of an indigenous process for making liquid fuels from Indian coals. The tests showed that the dry ash moving bed process is amenable to gasification of high ash Indian coals. The cold gas efficiency of the process is about 88% for oxygen-blown operation and is about 74% on air-blown mode.
IICT's participation in making a comparison of nine different IGCC technologies that were being developed abroad that culminated in the preparation of a Techno- Economic Feasibility Report (TEFR) for a 600MW IGCC plant when using a very high ash Coal from North Karanpura, Jharkhand for comparing four different IGCC processes including the indigenous Moving bed process with NTPC's conventional thermal power plant of same capacity in 1992.
In line with the activity on hand, i.e., Coal gasification for IGCC power generation, it was prudent that, IICT took up work on the Gap areas in IGCC technology and accordingly, a project on Development of a bench- scale process for Hot Clean Up of the Fuel gases from a coal gasifier was taken up with the support of Dept, of coal. The process operating at 850oC and 20 bar is intended to use adsorptive techniques for the removal and recovery of the sulphur components from the fuel gases before being combusted in a Gas Turbine, while ceramic candle filters were tried for particulates control. In order to save on the operating costs of coal gasification plant, Physical Simulation Environment was chosen for the experimental studies, i.e., to prepare a pressurized, hot, dusty coal gas mixture from pure gases and then subject it to Desulphurization and Filtration. Desulphurization is achieved in an adsorber with two separate beds of mixed metal oxides having different affinities towards sulphur. As a result, sulphur trapped in the reactor gets released as elemental Sulphur by-product, during the regeneration of the metal oxide sorbents. The project was successfully completed in 2006.
As a sequel to the successful Process development on Hot Cleanup of Coal-derived Fuel Gas at 850oC and 20kg/cm2 for removal of dust by Filtration through Ceramic Candle Filters and Sulphur compounds (H2S & COS) by Chemisorption on mixed metal oxide sorbents using simulated gas mixtures (2006), Indigenous development of another process as desired by the user industry, namely BHEL (R&D), could be successfully done (2011) for Cleanup of product gas from a Pressurized Fluidized Bed Gasifier (PFBG), carried out at a medium temperature of 500oC and 20kg/cm2, addressing the adsorptive removal of sulphur compounds (Desulphurization) along with removal of trace contaminants such as, Ammonia (Denitrification) and Alkali Metal Vapour (Dealkalyzation). Some more studies on regeneration of the spent sorbents are currently under progress. Second phase of the project involving design, fabrication, erection, commissioning and operation of a Gas Clean up system in tandem with the PFBG Pilot plant of BHEL R&D at Moulali will be taken up soon.
Fuel cell is an energy conversion device, which transforms chemical energy into electrical energy directly without the Carnot Cycle limitation on efficiency. It is environmentally benign and presently the only technology which can satisfy stipulations of the EPA. Hydrogen forms the basic fuel for the fuel cells. Hydrogen in turn is produced from a variety of conventional feed-stocks viz. methanol, coal gas, natural gas, LPG etc., by steam and/or air reformation. Although, hydrogen production technologies from conventional fuels are well developed, production of fuel cell grade hydrogen involves special techniques and materials. The challenges are development of suitable catalysts for reformation and purification and configuration of a reactor to maximize net energy availability. Sponsored by the Ministry of Non-Conventional Energy Sources, IICT has successfully developed a 10 kW Integrated Methanol Reformer Fuel Cell System including the technology for making all necessary catalysts. The reformer-fuel cell system was fully tested for self sustainability and continuous operation without supply of any energy from external sources by optimally utilizing energy from the excess hydrogen produced fully accounting for internal energy requirement. Later, a methanol reformer to suit 50 kW PEM Fuel Cell power pack was developed and demonstrated.
Coal & Gas Technology Division has been continuing to serve SMEs and major industrial clientele alike in carrying out various analytical works entrusted to the group in evaluating different solid, liquid and gaseous fuel samples according to ASTM standard procedures, as prescribed by Bureau of Indian Standards, and incorporated in the Departmental operating procedures of ISO: 9001 Quality Standards as the service activity was undertaken according to ISO. Coal & Gas Technology was fortunate to have had its leadership from eminent technocrats such as Dr.MG Krishna, Dr.R.Vaidyeswaran, Dr.Ramacharyulu, Shri K.Seshagiri Rao, Dr.DP Agrawal, Shri TSR Anjaneyulu, etc., in the past.
Major Technologies Developed/Transferred
- Low Temperature Carbonization (LTC) of High Ash Coals
- Briquetting of Char Fines to make Shaped Fuel from Coke breeze
- Moving Bed Gasification of High Ash Indian Coals
- Hot Gas Clean Up
- Warm Gas Cleanup
- Methanol Reformer for Fuel Cell Based Energy Systems (10-50 kW range)
- Coal S&T Services