NATURAL DRAFT COMBUSTION ZONE OPTIMIZING METHOD AND APPARATUS

摘要

ABSTRACT OF THE DISCLOSURE"NATURAL DRAFT COMBUSTION ZONE OPTIMIZINGMETHOD AND APPARATUS"Control method and apparatus for optimizing theoperation of a natural draft combustion zone through which aconduit containing a process fluid to be heated passes, bydecreasing the supply of combustion air until one or more of thefollowing predetermined limiting conditions is reached: maximumCO in the flue gas, minimum O2 in flue gas, minimum draft in thecombustion zone, maximum temperature of the outer surface of saidconduit, and increase in the rate of fuel addition above aminimum amount. When a limiting condition is reached, the supplyof combustion air is increased until the limiting condition is nolonger present, and the cycle then repeated.