Cogenerating plant electricity from

Cogeneration is an energy conversion process wherein heat from a fuel is simultaneously converted to useful thermal energy (e.g., process steam) and electric energy. The need for either form can be the primary incentive for cogeneration, but there must be opportunity for economic captive use or sale of the other. In a chemical plant the need for process and other heating steam is hkely to be the primaiy in a pubhc utility plant, electricity is the usual primary produc t. 

Utility plants primarily employ reheat condensing turbines, whereas cogeneration plants and larger process industries that produce their own electrical power tend to employ extraction turbines. Both types of turbine rely on a surface condenser to receive exhaust steam from the LP turbine stage and condense it to liquid for reuse. 

Table III. Results of Energy Costing and Exergy Costing of Electricity and Steam from a Typical Cogenerating Plant.

Comparison of these figures shows that cogeneration plants using steam-based processes cannot supply the electricity requirements of the consumer on the basis of power-heat cogeneration. On the other hand, small condensation power plants on industrial sites are generally not competitive with the large installations of electricity supply companies. This follows from the decline in capacity of industry-based power stations in West Germany (Fig. 57), which is due entirely to the closure of condensation... 

Finally, EVO had decided to accept the helium turbine from the manufacturer in spite of nonconformance with the supply contract. This decision was made because helium-specific experiences could nevertheless be gained with the actual plant conditions and because the plant could be operated (in spite of the lower electrical power) as a cogeneration plant satisfying the required district heat demand. 

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