Bentley Mills: Boiler Control System Upgrades
Bentley Mills uses a large quantity of steam throughout their manufacturing process chain. In 2014, Bentley Mills began implementing a project to upgrade the control system for one of its largest natural gas fired boilers (Boiler #1) at its facility in the City of Industry, Los Angeles. Bentley Mills has been operating the facility since 1979 and employs over 300 people. The facility makes commercial modular carpet tile, broadloom and area rugs in its 280,000 square feet of manufacturing space.
The project consisted of upgrading the controls system and adding a combustion gas analyzer and a variable speed flue gas recirculation fan.
MoreAfter being in operation for 20 years, the controller of Boiler #1 was in need of replacement. The project was completed with higher savings than were estimated. Additionally, this project improved the boiler and steam system efficiencies without negatively impacting occupant comfort, process efficiency, or production output.
LessAttempting to upgrade this frequently used system was tricky due to manufacturing needs and scheduling demands. Once the equipment was received, it was all a matter of logistics and proper planning. All changes to the boiler had to occur during off-peak hours of production in order to ensure continuous production efforts without disruption to product schedules and targets.
MoreThe new combustion controller monitors the fuel-to-air ratio and optimizes excess oxygen in such a way as to maximize the efficiency of the combustion process while maintaining safe and stable boiler operation. In addition, the flue gas recirculation fan improves performance by lowering the maximum flame temperature to the minimum required level. The recirculation fan also reduces nitrogen oxide emissions by lowering the average oxygen content of the air. Optimizing the exhaust gas composition and minimizing the stack temperature reduces energy losses, minimizes O&M costs, and extends the useful lifetime of the boiler. Once implemented, the upgraded boiler controls yielded annual energy and energy cost savings of 11,000 MMBtu/year and $53,000. The boiler’s energy intensity also improved by 15.2%. With project implementation costs of $104,000 the project yielded a simple payback of just under 2 years.
LessContinuously monitoring the exhaust gas composition, optimizing the fuel-air mixture, and reducing the flame temperature will minimize the boiler’s ongoing O&M costs and extend the equipment’s useful lifetime.
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