Technical analysis for preferring more efficient and green technology for thermal power generation: "Advanced-Ultra Supercritical 760°C"
This paper deals with the technical analysis for preferring more "Efficient and Green” of “Advanced-Ultra Supercritical 760°C technology for power generation for achieving more savings on Efficiency, Capital Cost, O&M Cost and with reduced GHG emissions instead of preferring "710°C technology". There is an urgent need for the shifting of the focus of technology development for proposed A-USC (Advanced Ultra-Super Critical) from A-USC-710°C to A-USC-760°C for availing greener and less costly cost power generation option. It is said that just a 1% gain in efficiency for a typical 700 MW plant reduces 30-year lifetime emissions by 2,000 tonne NOx, 2,000 tonne SO2, 500 tonne particulate matter and 2.5 million tonne CO2. Further to that improvements in the Efficiency will not only decrease operating costs and make better use of fossil fuels, they will also reduce the emissions.
This paper describes how the concept of advanced ultra-super critical technology came in to existence in India and how the Government of India gave thrust to develop this technology. This paper on technology side covers the cycle conditions used and performance and efficiency of the technology. This paper also reviews the comparison of different technologies vis-à-vis parameters of steam temperature, pressure of Advanced Ultra Supercritical and sub-critical technologies. The information on work done on Boiler material selection based on strength and stability is also covered. The aspect of saving on the part of material, thickness and size are also discussed. The study indicated that such work has earned ASME Boiler and Pressure Vessel Code that regulates the design and construction of boilers and pressure vessels. The paper also has discussions on the A-USC 760°C technology development including test-runs, performance runs and component test accomplished for 1,00,000 hours (11+ years).
The review of the development of this technology indicated that the study started as early as 1995 outside India and India turned to this technology around 2010. An insight into the development of special steel containing different proportions of Chromium and Nickel indicated that material properties are greatly improved and operations could be done at 760°C leading for cost reduction and improved environmental parameters. In summary and conclusion recommendation emerged after the discussions is also given for the selection of most suitable and appropriate technology. For the purpose of ready understanding the work done by leaders in A-USC their few slides are re-produced here in the paper.