What is the primary function of a boiler economizer?

The primary function of a boiler economizer is to preheat feedwater before it enters the boiler. This process enhances overall energy efficiency by capturing some of the waste heat from the flue gases that exit the boiler. By utilizing this residual heat to warm up the feedwater, the economizer reduces the amount of energy needed to heat the water to its boiling point, which can lead to lower fuel consumption and improved boiler performance.

Preheating the feedwater not only increases thermal efficiency but also helps to minimize the thermal shock on the boiler components, thereby extending their lifespan. As the feedwater enters the boiler at a higher temperature, it requires less energy for heating, leading to lower operational costs. This efficiency is critical in high pressure boiler systems where maximizing thermal performance is essential for safe and cost-effective operation.

While other options mention increasing steam pressure, reducing emissions, and controlling steam quality, they do not directly align with the primary mechanism that an economizer performs, which focuses specifically on optimizing the preheating of feedwater.