Water circulation in heavily loaded recovery boilers & single drum conversions

Many recovery boiler users are facing requirements to increase the boiler capacity. Equipment and process changes such as replacing direct contact evaporators with high efficiency economizers increase the steaming capacity to values that are usually much higher than the original boiler design conditions. The effect of the increased steaming capacity on boiler circulation is discussed in this paper. This paper also discusses the conditions under which the two drum arrangement is usable and when a single drum conversion should be considered.