After the evaporative tubes, the steam-water mixture enters the boiler superheater
. Further, the superheated steam along the steam line is directed to the impellers of the steam turbine.
Based on the parabolic law of high-temperature oxidation, Arrhenius equation, and related basic theories of heat transfer, an oxide scale growth model of boiler superheater
tubes is proposed through iterative technique .
During introduction of sonic cleaning at that boiler superheater
, five test series with duration of 15-25 days were performed.
The particles in question are solid iron oxides, mostly magnetite, that form on the surfaces of boiler superheater
, reheater, and steam piping.
The probes were designed as waterfilled heat pipes whose working (heat-absorbing) surfaces (with outer diameter of 35 mm) have temperatures on the level of the corresponding surface temperature of an actual boiler superheater
(up to 550 [degrees]C) or economizer (300-350 [degrees]C).
Even pinhole leaks can cause damage to adjascent tubes, especially in the boiler superheater
and reheater sections.
The effect of other factors (steel preparation, tube manufacturing technology, etc.) could not be, unfortunately, predicted with satisfactory accuracy, so each new steel should be tested in conditions similar to oil shale boiler before making final conclusion about its convenience for oil shale boiler superheater