NTPC is constantly engaged in upgrading technologies to improve efficiency and meet environmental concerns. According to R.K. Jain, Director (Technical), steps taken in this regard include improving rankine-cycle efficiency in pulverised coal-fired thermal units by adopting supercritical and ultra supercritical steam parameters and increasing steam parameters of upcoming 500 MW units, as also developing integrated gasification combined cycle (IGCC) for higher efficiency and lower impact on the environment.
Renovation and modernisation of aging operating units is also being undertaken. Advanced-class gas turbines are being used for combined cycle gas turbine (CCGT) plants. Other steps include flue gas desulphurisation (FGD), high concentration slurry disposal (HCSD) and use of non-coal power generation technologies such as CCGT, hydro, wind, solar, biomass and nuclear, Jain says. NTPC will be the first to use the wet lime stone FGD system in coal-based power plants in the country in its Bongaigon plant, for containing the sulphur dioxide emissions from the plant as the sulphur content in the linked coal is high. It is also exploring HCSD for fly ash disposal for some of the upcoming projects such as North Karanpura and Jhajjar. The HCSD technology uses less water, does not pollute groundwater, does not create dust hazard at the disposal area, and saves energy in ash transportation, says Jain.
On whether NTPC is looking at technological tie-ups in this regard, he says: NTPC, in association with NEXANT, has already done a study on gasifiers suitable for Indian coal. Indian coal has already been test fired at various pilot plants at BHEL [Bharat Heavy Electricals Limited], GTI, USA and KBR (USA). Although IGCC technology is quite mature worldwide and plants up to the rating of 335 MW are known to be in operation, this technology needs to be developed for Indian coal for implementation here. Gasifiers need to be developed for high ash content, low GCV Indian coal with high ash fusion temperature reactive coal. NTPC is looking for partners to develop jointly the technology for Indian coal.
Dinesh ChandraCOMMents
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