Page 23 - Boiler plant and distribution system optimization manual
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8 Boiler Plant and Distribution System Optimization Manual
Figure 1.10 ASME Allowable stress curves for various tube metals used for
superheater tubes. Note how allowable stress falls off over 1100°F.
Figure 1.11—To achieve a stable final steam temperature a combination of radi-
ant and convection superheater designs are used.
As the steam leaves the primary superheater control superheated steam. temperature. The at-
it passes through an attemperator, into which rel- temperator is installed in the steam header that
atively cold feedwater is sprayed into the steam connects the primary superheater to the second-
to regulate final superheated steam temperature. ary superheater. It consists of a thermal sleeve in-
Figure 1.12 illustrates an attemperator design. side the steam header designed to absorb thermal
The function of the spray attemperator is to shock and an atomizing water spray nozzle ex-
