The world’s major power generations rely on the use of fossil fuels. Despite the growth of renewable energy utilization for power generation, the power generation through fossil fuel route has been indispensable and massive. One of the major threats to this source of energy is the depletion of fossil fuel. Hence effective use of energy conversion technologies is warranted.
An analysis of energy and exergy helps to develop an improved technology for energy conversion. Exergy analysis is an effective tool for optimization and process analysis. Now a days, greater efforts are to be given for reducing air pollution and global warming. This can be achieved by operating the plant using efficient and improved technologies.
Circulating Fluidized Bed (CFB) technology has been found to be conducive for environmental issues.Gungor carried out studies on size of heat transfer surfaces to ensure the proper operation and optimization of circulating fluidized beds (CFB’s), considering particle based approach for the 2D CFB model. The influence of water flow rate and heat exchanger tube diameters are investigated based on second law of thermodynamics.Auracher studied the fundamental aspects of energy application for the optimization of energy process.It is concluded that thermodynamic process optimization is for the saving of exergy rather than energy. Further, an energy and exergy balance analyses proves to be an effective tool to quantify the exergy losses for optimizing the plant process parameters.Ganapathy et al.conducted an exergy study for a 50 MW power plant, which uses lignite as fuel. The study finds out about 39% of energy loss in the condenser and 43% of exergy destruction in combustion system. Erdem et al.conducted comparative study of nine different capacities of power plants using low grade fuel. They developed a thermodynamic model using first law and second law as the first stage. The developed model has been compared with design values of those power plants as the second stage.
Finally, the design point performance analyses are made for both energy and exergy basis. This proves to be more helpful for the designer. Aljundi studied the energy and exergy analysis of a power plant of capacity 56 MW using heavy oil as fuel. The energy efficiency of the plant is 26%. Two thirds of energy loss occurs in the condenser and the exergy loss is about 9%. Seventy seven percent of exergy loss occurs in boiler system and the exergy efficiency of the cycle is estimated as 25%. Khaliq and Kaushik studied the second law analysis of high thermal efficiency of re-heat combined Brayton/Rankine power cycle. It has been concluded that overall exergy destruction is about 50% in combustion chamber. Addition of further two re-heater stages enhances the combined cycle efficiency.