Power Plant Water Management
A Novel Concept for Reducing Water Usage and Increasing Efficiency in Power Generation - University of Pittsburgh
A unique gas turbine intake air cooling technology, using ice to cool the air, can be applied to combined-cycle power plants in order to increase overall efficiency, improve heat rate, and have the additional benefit of recovery of pure water as moisture condenses out of the intake air as it is cooled before entering the turbine. The exact increase in power available and water recovered from a particular gas turbine as a result of inlet air-cooling depends upon the machine type and plant location as well as ambient temperature and humidity. However, turbine design curves can be used to make an estimate of this benefit for gas turbine generators. The improvement should be greatest in hot, dry weather. The addition of an inlet cooler is economically viable when the value of the increased output exceeds the initial and operating costs, and appropriate climatic conditions permit effective utilization of the equipment. Several types of intake air cooling have been used on natural gas fired turbines, however, the use of a chilling system tied to ice thermal storage offers the benefit of making ice during off-peak periods and then using that ice to cool intake air during peak loads thereby keeping the kW output available for sale during peak demand period. In the process of cooling, the air passes through the dew point and water condensation occurs. This water is very pure and has both in-plant and out-of-plant usage potential. These include:
- NOx reduction (introducing water into downstream stages of the turbine)
- Boiler feed water makeup
- Cooling tower water makeup
- Mineral-free water for process or power applications
- A clean water source for commercial and domestic uses
If the proposed gas turbine intake air cooling technology is successfully developed for commercial applications, a large reduction in net water usage and a significant increase in total power output (through higher kW output during peak periods) and lower fuel costs (through higher efficiency) could be achieved for power generation in this country.
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- For further information on this project, contact NETL Project Manager, Barbara Carney.