Time and wear have taken their toll on aged mechanical control systems, deviations from the norm throw air-fuel ratio control out of the window: coal consumption increases and steam output fails.

Operator skills and interventions of the highest order are then needed to approach original production levels. Repairs and overhauls of controls have invariably to be outsourced to a dwindling field of specialists, with negative consequences on expenses and down-time.

This is a familiar scenario with many coal-fired boilers, but it no longer needs to be so.

In November last year three old hands in the industry – Gert Coetzee, Richard Austin and Jonathan Levin, who amongst them have almost 90 years of experience in the industry – joined together to form CAL Boiler Control Systems.

CAL makes use of a technology that does away with all of the ailments of the old mechanical system where, from the gearbox to the dampers, no less than 23 points are contained where incorrect assembly, unauthorized tampering or just plain wear would bedevil efficient firing.

Gert Coetzee tells CBN that the CAL Boiler Control System neatly locks all settings away “from the efforts of the un-schooled, the tamperings of the idle and the ravages of wear”: it’s all encapsulated within a PLC and AC variable speed drive-package. Optimum settings for a particular fuel grade are easily found and the burden on the operator is much reduced.

“Much closer control of the air-fuel ratio is being achieved and feedback from our installations indicates immediate coal savings of at least 12%,” Coetzee says.