Heating the air inlet to a gas turbine rather than cooling may appear contrary to what we know about thermodynamic efficiencies. However, the benefits of heating intake air during part-load operation can enhance overall plant flexibility.
On a typical gas turbine, output is regulated by adjusting the inlet guide vanes. However, there is a point at which closing these guide vanes may introduce Issues such as flow separation and combustion – this has a significant impact on the efficiency of the gas turbines. By preheating induction air, turbine output is reduced, but it’s possible for the guide vanes to remain fully open. As a result, there are no issues involving a pressure drop ahead of the compressor stages or flow separation, and high overall efficiency is possible.
A major power producer in Thailand was facing reliability problems with their air heater pumps (used to heat up air on the inlet of their GE LM6000 gas turbine) due to leaking packings. The plant was operating with minimum staff and was unable to monitor and tighten the packings on the pump. This lead to loss of hot water and pump reliability problems.
After an extensive study, the power plant decided to upgrade all their Torishima pumps with PSS due to our long 30 year experience of mechanical seal retrofits in Thailand. The technical team at PSS selected John Crane T4610 Series for this upgrade. The main reason for this selection was due to its robust design and ease of installation due to minimal stuffing box modifications.
The pumps were retrofitted in PSS’s Service Facility in Rayong. All the air heating pumps were successfully commissioned and have now improved the reliability of the entire air preheating operation..