A fast control algorithm for near optimal control of industrial combustion

Fossil fuels vary in composition, and varying amounts of oxygen are required for their combustion to minimise energy loss and pollution. The problem is treated as an optimal control problem which generally covers all operational conditions. For this a performance criterion is formulated as a function of measured 0₂ and CO concentrations in the exhaust gas. This criterion determines uniquely the optimal balance between remnant CO and surplus O₂ for any load level and any fuel quality. The procedure presented drives the combustion to a near-optimal operating point more quickly than previous methods. For this a synthetic reference input has been developed as a nonlinear function of both measurements. The function defines a monotonic characteristic which for all operating conditions passes the zero line approximately at the optimal operating point. Thus, a simple set point control algorithm can be applied which reaches the optimum in only one or two control steps