Gas Turbine - Inlet Guide Vane, How IGV work

Inlet Guide Vanes (IGVs) deliver air to the inlet of a gas turbine’s axial compressor. While maintaining proper fuel-to-air ratio through various load ranges, they minimize the potential for unwanted emissions. In present-day Combined Cycle power plants, IGVs ultimately control the exhaust gas temperature – a critical input to the Heat Recovery Steam Generator (HRSG). Stable control of the exhaust gas temperature enhances the combined unit’s level of efficiency. Many current day turbines use low NOx combustors that require a lean air-fuel mixture. As hot gas temperatures decrease, the formation of NOx also decreases. With a higher air mix, it’s critical to control the exact amount of air into the combustors – especially during low loads.