Condensation-Induced Water Hammer in District Steam Systems—Circumstances Resulting in Catastrophic Failures

摘要

Waterhammer accidents in district steam systems which kill operators are, in my experience, always due to Condensation-Induced Waterhammer. The other classifications of waterhammer that can occur in steam systems: Column-Closure, Sudden Choking at an Orifice due to flashing hot water, sudden valve closure, and steam-blown slug flow (which is not, technically, waterhammer) don't generally result in overpressures powerful enough to breech steam components. This paper describes the most prevalent circumstances which lead to catastrophic waterhammer accidents in district steam systems based on the author's experience in steam accident investigations. Examples are drawn from actual accidents to describe each circumstance. The circumstances can be grouped into two distinct causation categories--both of which are necessary for condensation-induced waterhammer to occur. Ⅰ. Circumstances which allow excess condensate to accumulate in a steam system. Ⅱ. Circumstances which permit steam to come into contact with, and be entrapped in, the condensate.