Device and method for controlling supply of steam into gas turbine compressor

摘要

A water droplet mist is sprayed into the air upstream of a gas-turbine compressor inlet to increase power output from the gas turbine. The water has the effect of lowering dry-bulb temperature of the air entering the compressor inlet. To supply an amount of water appropriate for anticipated ambient conditions, a plurality of different capacity pumps (108, 109, 110, 111) are provided to supply water over a wide range of water flow rates. The control system for the pumps avoids the use of a set-point temperature for the inlet air obtained from measurements taken downstream of water injection. The operator inputs a desired relative humidity of air entering the compressor, and the control system (120) determines the appropriate flow rate of water using the following measurements: flow rate of dry air to the compressor(104); flow rate of inlet water; dew point temperature of the inlet air; dry-bulb temperature of the inlet air; and temperature of the inlet water.