What is the function of a deaerator in a geothermal power plant, and why is it critical for efficient operation?

The function of a deaerator in a geothermal power plant is to remove dissolved gases, primarily oxygen and carbon dioxide, from the boiler feedwater. Boiler feedwater is the water that is heated to create steam, which drives the turbine. These dissolved gases, especially oxygen, are highly corrosive and can cause significant damage to the boiler, turbine, and other plant components. Oxygen accelerates the corrosion of metals, leading to pitting, cracking, and eventual failure of equipment. Carbon dioxide can dissolve in water to form carbonic acid, which also contributes to corrosion. The deaerator operates by heating the feedwater to near its saturation temperature, which reduces the solubility of the dissolved gases. The heated water is then sprayed into a large vessel, typically a tray-type or spray-type deaerator, where it comes into contact with steam. The steam strips out the dissolved gases, which are then vented to the atmosphere or recovered. The deaerated feedwater is then sent to the boiler. A deaerator is critical for efficient operation because it minimizes corrosion, which reduces maintenance costs, extends the lifespan of plant equipment, and improves plant reliability. By preventing corrosion, the deaerator helps to maintain the efficiency of heat transfer in the boiler and turbine, ensuring optimal power generation. Furthermore, reducing corrosion minimizes the risk of unscheduled shutdowns, which can be costly in terms of lost production and repair expenses. Therefore, the deaerator is an essential component of a geothermal power plant for ensuring long-term, reliable, and efficient operation.