DEVELOPMENT OF SUPERALLOYS FOR NEXT GENERATION COAL-FIRED POWER SYSTEMS: CHALLENGES AND OPPORTUNITIES
Oluwole, O.O.
Department of Mechanical Engineering
University of Ibadan, Ibadan, Nigeria
e-mail:oluwoleo2@asme.org
ABSTRACT
The Federal Government’s 7-point agenda has as high priority, power generation to provide stable electricity supply for all sectors of the Nigerian community. Inability to manage properly the oil and gas sector, problems in the Niger delta and vagaries in the oil and gas industry are serious signs of domestic energy crisis which if not well managed will spill into very deep social crisis in the near future. There is the mooted option of nuclear powered electricity generation which probably might be the best and cheapest for the country if issues like waste disposal and security are solved. This option though feasible needs long term planning because a huge chunk of our nuclear scientists and engineers have migrated to foreign lands. With this scenario, it is expedient for the country to look at combinations of power generation using fossil fuels, coal, and renewable energies. An important area which has not experienced any growth is coal powered electricity generation partly because of the mess from coal combustion, the obnoxious effluents, inefficiency of operation and the new found oil fields. While not oblivious of the effect of coal- powered plants contribution to global warming and acid rain, the US coal- fired power plants currently supply more than half that country’s energy needs while the Directorate of Energy (DOE) is pursuing clean coal initiative (CCPI), Future Gen and Vision 21 which are all programmes aimed at getting to near zero the carbon emissions in coal power generation. Nigeria needs to tap into this area of clean coal initiative. One of the major challenges in development of clean coal technology is in the area of materials technology for the development of boiler/steam turbine and Integrated Gasification Combined Cycle (IGCC) systems. For example, as the most critical component in the construction of boiler systems, the superheater tubes have to undergo the most severe service conditions and must meet stringent requirements with respect to fireside coal-ash corrosion/erosion, steamside oxidation and spallation, along with creep strength, thermal fatigue strength, and weldability. This paper presents the challenges of developing novel superalloys for these systems and the methods being advanced to overcome the problems.
Keywords: clean -coal -technology; superalloys-development; challenges;opportunities