Deaerators are a critical part of a heat recovery steam generator or HRSG. They remove oxygen, carbon dioxide and other gasses from water that flows into a boiler. From there, the boiler will heat the water, also called feedwater, producing steam that provides energy within a turbine system. There are two types of boiler daeratrors, and when researching for a deaerator supplier, knowing the difference is key.
The spray-type deaerator is made of one cylindrical container that acts as both the deaerator and storage for water inside a boiler. Inside a horizontal cylinder, feedwater enters the system as a spray where it is preheated before entering into the area of deaeration. Preheating the feedwater allows for the dissolved gases to be removed more easily during the process of deaeration. In the deaerator section, the gases are removed at an exit at the top of the cylinder, and the deaerated water is pumped into the boiler system for storage.
Spray and Tray-type Deaerator
Unlike the spray-type, this system is made of two separate containers. One horizontal container serves as the storage tank for the deaerated feedwater, and on top of this container is a second container where the deaeration process occurs. The two sections are separated by perforated trays to allow water to move between the two areas. Similar to the spray-type system, the feedwater enters the deaeration chamber as a spray that combines with rising steam before flowing into the perforated trays. The steam removes the gasses, allowing them to rise out the upper vent of the system, and the deaerated water is pumped into the second cylinder to be stored.
A properly functional deaerator removes gasses that can cause rust inside turbines and machinery. By maintaining the deaerating and performing routine checks, a company can alleviate headaches that can occur when elements become corrosive.