Refractory wall curing of the fluidised bed boiler.

We have performed a refractory curing operation of the fluidized bed boiler type OFz-450B in Żerań CHP Plant in Warsaw. The contractor of refractory lining of the total mass of ca.  760 t was IZOMAR Sp. z o.o., which was our Orderer at the same time.

The dry-out operation was made by means of a system of sixteen burners, specially designed and fabricated totally by our company, located in inspection hatches to individual boiler elements, and supplied with light fuel oil. For the dry-out/curing process need we developed a process procedure. The accepted solution allows for very even heating of the refractory lining and maintaining a precise temperature rise rate in the refractory being dried.

At a designing phase of additional burners we had to overcome a lot of difficulties of design nature, as well as those directly associated with the dry-out process technology. In our opinion it is worth noting that the applied solution provided a proper quantity of combustion air, which distinguished it from others applied so far.

The refractory lining of OFz 450B fluidized bed boiler is made of many kinds of insulation and refractory concrete, as well as fireclay elements and plastics of various moisture content. Due to the combustion process nature in fluidized bed boilers, the refractory lining has a different thickness and density at different boiler elements. The aforementioned conditions regarding the complexity of the refractory structure caused, that the issue to select the heat output of individual oil burners was a very responsible and difficult task. For that purpose the thermal calculations were made which based on internal energy changes balance during a simulated heating of individual boiler elements.

The dry-out process of OFz 450B boiler refractory lining was carried out according to a curve provided by the refractory contractor, which was a guarantee of the process correctness. Based on a visual inspection after the dryout process completion, the operation was positively evaluated by representatives of FK RAFAKO SA, IZOMAR Sp. z o.o. and Żerań CHP Plant. In order to learn more on the effects of the dry-out process we encourage to contact our Orderer.