A feedwater economizer is a device that enhances boiler efficiency by recovering waste heat from flue gases to preheat incoming feedwater. This process reduces fuel consumption and operational costs.
How They Work
In steam boiler operations, flue gases expell at high temperatures, carrying away valuable energy. They capture this waste heat and transfers it to the boiler’s feedwater. By preheating the feedwater, the economizer decreases the energy required to convert water into steam, which improves overall boiler efficiency.
Efficiency Gains and Fuel Savings
A feedwater economizer can lead to significant fuel savings. According to the U.S. Department of Energy, boiler efficiency can increase by approximately 1% for every 40°F reduction in flue gas temperature. Overall, an economizer can reduce fuel requirements by 5% to 10%, often achieving a payback period of less than two years.
Installation Considerations
Installing an economizer involves modifications to the flue gas ducting and feedwater piping. The complexity of the installation depends on the existing boiler setup and operating conditions. It’s essential to assess the boiler’s current stack temperature and the temperature of the incoming feedwater to determine the potential efficiency gains.
Feedwater Economizer Maintenance and Operation
Regular maintenance is crucial to ensure the economizer operates effectively. This includes periodic cleaning to prevent soot buildup, inspections for corrosion or leaks, and monitoring temperature differentials to detect performance issues. Proper water treatment is vital to prevent scaling and corrosion within the economizer.
Economic Benefits
The investment in a feedwater economizer can yield substantial economic benefits through fuel savings. A boiler that makes 45,000 pounds of steam per hour at 150 psig could save about $386,400 each year. It will also need a stack temperature of 500°. That is assuming 8,400 operating hours per year and a fuel cost of $8.00 per million Btu.
Benefits of Waste Heat Recovery for Industrial Facilities
Heat recovery system economizers are particularly useful in industrial settings. Such as where boilers are for steam generation, like power plants, manufacturing facilities, refineries, and chemical plants. They are ideal for applications with high-pressure steam systems, where energy recovery can make a significant impact on efficiency and cost savings. They are also beneficial in facilities that operate continuously. These could be facilities like food processing plants, hospitals, and large commercial buildings. They can help reduce fuel consumption by preheating the feedwater before it enters the boiler. In short, any operation with a steam boiler system can benefit from installing a feedwater economizer to improve energy efficiency and reduce operational costs.
Conclusion
Incorporating one into your boiler system is a practical and cost-effective strategy to enhance efficiency and reduce fuel consumption. By recovering waste heat from flue gases, economizers not only improve energy utilization but also contribute to significant operational cost savings.
Watch this Youtube Video for another view! You can also refer to the U.S. Department of Energy’s publication on using economizers for waste heat recovery.