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Combustion Control

To complement our burner management systems we have developed a significant number of combustion control strategies to work with most fired applications. Our strategies are designed to provide optimal and safe air/fuel ratios to the burners, regardless of load. These may be as simple as a single PID loop providing firing rate control on a natural draught heater to complex, mass flow schemes controlling multiple fuels and waste streams with varying calorific values.

Equations or tables
For commonly used fuels like natural gas and fuel oils we have evolved a comprehensive set of standard function blocks with equations that continuously calculate a safe and optimal amount of air and fuel. And for more exotic fuels we have a number of ‘curve-fit’ tables with algorithms that allow us to accurately match interpolated data sets.

Increased efficiency
For the most fuel-efficient and optimised strategies our standard combustion control solutions are ‘fully metered’, using 3-term control loops with set points derived from calculations or tables. That is, we continuously measure the actual air and fuel flows or pressures and make constant adjustments to them, minimising the amount of fuel consumed to meet the process requirement. We work with a number of partner instrumentation companies and can provide a complete instrument package. Alternatively, we can interface with most existing process control instruments.

Enhanced capabilities
In addition to our standardised lead-lag, cross-limited schemes, our power boiler solutions can also include other control loops such as drum water level control, steam flow feed-forward, O2/CO trim and induced draught control. The larger schemes may also include flue gas analyser data to monitor and record SOX and NOX for environmental purposes.

Platform independence
Our combustion control strategies can be implemented on a number of platforms. When associated with one of our FAS BMSs we incorporate the strategy into the PM (non-safety controller). When using one of our tailor made BMSs the strategy may be incorporated in a stand-alone controller from the same family or, more frequently, as part of the overall DCS scheme.

Available solutions & services

  • Detailed prescriptive functional description.

  • Standalone loop controller type solutions.

  • Fully configured Process Automation Control (PAC) system incorporating a graphics based touch-screen operator interface.

  • Tailored or pre-engineered systems.

Potential control strategies

  • Firing rate control for fired heaters or supplementary firing systems.

  • Complex combustion control managing multiple fuels and burners employing mass flow calculation techniques.

  • Fully integrated boiler control with drum water level control, steam flow feed-forward, oxygen trim and induced draught.

System functionality

  • Bi-directional cross-limiting and lead lag strategies for air fuel ratio control, incorporating out-of-ratio alarms.

  • DCS and BMS communications.

  • HMI depicting configured loop template displays, diagnostics and trend pages.

  • Password protected access to full loop tuning and sensor range configuration.

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