Yanche wrote:What can we do with what we have?
1. Make the aquastat differential a minimum. This will get the combustion blower burning sooner, hopefully reducing how much the fire get disturbed because the blower cycles on and off more frequently.
2. Lower the ashing rate by lowering the grate motor speed. "rychw" is trying this.
I all this fails then what's left? Changing the concentration of coal gases so that an explosive mix doesn't exist, i.e. a purge of the boiler firebox. A control method is still to be developed.
I would add one element to the above list:
3. Raise the level of the burning coal in the firebox so that the coal gas is always exposed to an ignition source. To put it another way continuously burn off the volatile gases rather than letting them accumulate.