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COGENERATION SYSTEMS. Presented By: ELAHEH TIMAJCHI. SELECTING COGENERATION SYSTEMS. Topping Cycle. Steam turbine with flue gas treatment Gas turbine with heat exchangers Diesel engine Steam or gas turbine with atmospheric fluidized-bed boiler Combined cycle
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COGENERATION SYSTEMS Presented By: ELAHEH TIMAJCHI
Topping Cycle • Steam turbine with flue gas treatment • Gas turbine with heat exchangers • Diesel engine • Steam or gas turbine with atmospheric fluidized-bed boiler • Combined cycle • Coal gasification combined cycle • Phosphoric acid fuel cell
Bottoming Cycle • Steam turbine • Organic Rankine turbine • Gas turbines
Relative Advantages of Cogeneration Technologies • Fuels used • Capital investment required • Efficiency in converting fuel to electricity • Electricity- to- steam ratio(the electricity produced per unit of steam generated) • Environmental effects
Technical Factors to be Considered • Process thermal energy need (temperature & pressure of the steam) • Fuels available • system reliability • Retrofit versus new installation • Electricity buy-back Selection Method • O & M requirement
Economic Factors to be Considered • Available capital • Rate of return required • Cash flow
Selection Method • Judgmental selection • Simulation of a few desirable designs • Examination of all systems
Summary These systems include topping-cycle systems and bottoming cycle are noticeable have payback periods of less than five years, and their heat rates and capital costs are lower than those for the conventional central power plants.
Summary The selection of an appropriate cost allocation method is the first step toward the economic evaluation of any co-generation project after the potential of co-generation for a process (industrial) or building (commercial or residential)
Summary • The optimization of a co-generation system’s size depends on the owner of the co-generation facility and on the purpose of the co-generation system. The optimum size of a co-generation system designed for industry may be significantly smaller than that of one designed for society. The size of a co-generation system vary substantially even under the same type of ownership. For example the optimum size of a co-generation system under an industrial owner who wishes to generate maximum cash flow from the co-generation project to support his or her main business may be larger than the size of the system under an industrial owner who co-generates only to meet process thermal or electrical needs.
CONCLUSION • Paper, metals, chemicals, and petroleum industries account for most known co-generation capacity ( 80% of the total U.S. co-generation capacity). • In most existing co-generation facilities, steam turbines are used to generate electricity. • Natural gas, bio-mass and waste are more important than other fuel types in co-generation of electricity.