Blocked Regenerators are causing not only problems with production capacity but also reducing thermal efficiency of Furnaces and thus increase the cost per produced ton of glass. Cleaning the Regenerators can solve both problems.
MELT OUT OF BLOCKED REGENERATOR
WHY Regenerator Cleaning?
• So that the furnace can «breathe» again
• To reduce fuel costs
• To avoid the need for an unscheduled furnace repair
The problem of blocked regenerators is not new in the glass industry, in fact it has been accommodated in regenerator design over many years by building the passage dimensions fairly large and by building more of them than necessary to permit the flow of gases under natural draught conditions.
It was generally understood that a regenerator was built twice the size necessary so that, as it gradually became blocked, the furnace would continue to function. The principal cause of regenerator blockage is the condensation of sulphates in the checker work.
The sulphates either come from the fuel, batch or additives to help melting the glass. The carry over from batch materials are also responsible for regenerator blockage. These materials have much higher melting points and are much difficult to remove by thermal cleaning. However, in most cases batch particles are stuck to the sulphates and will run down the regenerator once these start melting.
The HWI Method
The method consists, briefly, of installing a service burner in the bottom of the regenerator chamber and gradually increasing the temperature.
The maximum permissible temperature limit is set in consultation with the customer with due regard to the refractory materials (normally the rider arches influence the limit).
By appr. 850°C the sulphates begin to melt and run down to the bottom of the regenerators, where they can be caught in a sand pit, and removed from there after resolidification.
This operation can be carried out on several chambers, simultaneously or consecutively, without interrupting production.
This method has been successfully carried out on hundreds of regenerative furnaces.
When the clogging of the regenerator is not due primarily to sulphates, or if the checker work has failed or in case of any other repair to the regenerator which is needed:
• HWI burners can be used to hold the furnace temperature while checkers are replaced or the repair has taken place
• HWI burners can be used for a controlled cool down and consequent heat-up after the repair of the damaged regenerator