Tubing Wastage in Fluidized-Bed Coal Combustors: Examinations of Tubing from Test Series 2, NCB (IEA Grimethorpe) Ltd. Facility

摘要

This study of wasted heat-exchanger tubing from the Grimethorpe PFBC Facility was conducted to characterize affected fireside surfaces and identify the mechanism/s responsible. Examinations showed that the wasted surfaces are not typical of those produced by erosion alone, as oxide deposits are present on all surfaces. Continual exfoliation of the normally-protective oxide layer is probably responsible for a major portion of tubing wastage. There are also indications of direct metal loss occurring through a series of events wherein repeatd formation and exfoliation of surface oxides produce an irregular metal interface that is mechanically deformed during combustor operation. The cold-worked metal protrusions, or platelets, on the roughened surface readily fracture from the tubing wall and are lost into the bed. 27 refs., 23 figs., 3 tabs. (ERA citation 13:008440)