What is the function of an economizer in a boiler system?

The function of an economizer in a boiler system is primarily to recover heat from the flue gases that exit the boiler and use that heat to preheat the boiler feedwater. By capturing and utilizing this waste heat, the economizer enhances the overall efficiency of the boiler system. Preheating the feedwater reduces the amount of fuel required to reach the desired steam temperature, thereby improving the system's thermal efficiency and reducing operating costs.

This process is particularly important in large industrial applications where energy conservation plays a critical role in operational efficiency. The improved efficiency can lead to lower emissions and better adherence to environmental regulations.

The other choices, while related to boiler operation, do not accurately describe the primary role of an economizer. Converting steam back into water pertains more to condensate recovery systems, while increasing the efficiency of a steam turbine is typically the function of turbine modifications or different turbine cycle configurations. Monitoring and controlling water levels in the boiler is managed by level control systems and does not relate to the specific function of an economizer.