Factors such as low capital cost, good match of power and heat requirements, and proven reliability, can sometimes lead an end user into purchasing mature gas turbines for use in a modern cogeneration plant.
Invariably, older gas turbines were not specifically designed for low NOx emissions and steam injection.
This paper presents what the author(s) believe to be the simplest method of modifying an existing fuel system design to provide the best NOx reduction possible using steam injection, without significantly increasing carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. Results of emissions tests are presented, along with a discussion on the projected limits for NOx control attainable using this new system.
Also presented, is an idea for improving cogeneration efficiency and capability, by placing the turbine cooling air cooler in the steam generation circuit.