Providing Services to the Energy Industry

The power plant under construction in Clinton Township, Pennsylvania is a highly efficient combined-cycle generation facility.  Combined-cycle power plants operate at higher efficiencies than traditional fossil-fueled plants by capturing much of the energy contained in the hot exhaust from the natural gas combustion turbines to generate additional electricity.  Using that energy, which otherwise would be wasted up the stack as hot air, is a major benefit of the combined-cycle design.

Energy from the exhaust of each combustion turbine is captured by a heat recovery steam generator (HRSG).  The HRSGs are so efficient that exhaust leaving turbines at more than 1,100ºF is reduced in temperature to below 200ºF by the time the heat recovery process is completed.  The HRSGs will be equipped with state-of-the-art emissions control technology including Selective Catalytic Reduction (SCR) and an Oxidation Catalyst, to reduce air emissions of nitrogen oxides and carbon monoxide that are generated during the combustion process in the gas turbines. 

HRSGs contain boiler tubes filled with ultrapure water.  Hot exhaust flows past these tubes, turning the water into steam.  The steam is piped to a steam turbine, which is also connected to a generator.  Steam enters the turbine at more than 1,000ºF and at a pressure of more than 2,000 psi.  After the steam has done its work spinning the generator, it is exhausted to the air-cooled condenser.  The air-cooled condenser condenses the steam back into water using large diameter fans to circulate air past tubes containing the steam.  The water is then returned to the HRSG in a closed-loop cycle to be reused.

The process flow diagram below shows a single combustion turbine and single steam turbine. 

Double-click thumbnail to enlarge image of Process Flow Diagram:


Click to download file: