BMS and CCS Experience
Applied Utility Systems, Inc. (AUS) has supplied DCS and PLC-based BMSs and CCSs for multi-burner fossil fuel-fired boilers. Provided below are details of two (2) projects. The first project, for the City of Glendale (Glendale), included both BMS and CCS using an open architecture DCS system. The second project, for the City of Burbank (Burbank), included more conventional PLC-based BMS systems.

City of Glendale
At Glendale, AUS supplied and installed a low NO_x system incorporating LNBs and Flue Gas Recirculation (FGR) as well as a new BMS and CCS. The system is designed to fire No. 2 fuel oil, natural gas, and LFG. As part of AUS’ scope of supply, both BMS and CCS were supplied. Two (2) boilers were covered by this project: Unit 3 is 20 MW and Unit 4 is 45 MW.

The control system is designed to automatically fire all of the available LFG to both maximize Glendale's saving in fuel costs and minimize NO_x emissions. Natural gas is used as a supplementary fuel to automatically make up the difference between the available LFG supply and total firing demand. If the LFG supply is interrupted, the control system smoothly switches to natural gas only firing. Without upsetting boiler operations, LFG firing automatically resumes when the LFG supply is restored. Fuel oil can be used as the supplementary fuel, if natural gas is not available.

The LFG heating value varies significantly over each 24-hour period. The control system automatically compensates for changes in LFG composition by utilizing data from an on-line fuel gas analyzer.

Safe operation of the boiler and its multiple fuels is achieved by incorporating a complete BMS in the control system. The BMS provides the standard firing safeguards and the additional interlocks required to allow safe utilization of FGR and LFG.

Color monitors provide the operators with burner and fuel status information and annunciate any alarm conditions. All operator input can be entered using a mouse device, avoiding the complexity of learning and entering commands from a keyboard.

City of Burbank
At Burbank, AUS supplied and installed LNBs as well as new BMSs. Three (3) boilers were covered by this project: Olive 1 is a 43 MW unit, Magnolia 3 is a 20 MW unit, and Magnolia 4 is a 29 MW unit. Each of the boilers is equipped with six (6) burners and is designed to allow for fuel oil or gas firing.

This project incorporated PLC-based BMSs which were designed and built by AUS. AUS was also responsible for interfacing each BMS with the existing plant CCS. The AUS BMS was based on the use of Allen-Bradley PLC5 hardware with all software configuration provided by AUS.

The BMS was a conventional oil- and gas-fired supervised manual system based on the requirements of NFPA 85.