Superheater Tube Arrangement in Steam Boiler

If this is a new boiler design then it does seem implausible that the organisation's design standards contain insufficient information on how to design a superheater arrangement! Superheating has been going on for many decades up to now.

• The number of tubes is constrained in the upper limit by the diameter of the flues down which any superheater element needs to be mounted and the number of flues.
• There should be a superheater header manifold at each end of the superheater elemments, each of which should have the same number of holes, and this may determine the number of superheater elements to be fitted. It is a simple task to count the number of holes in each header manifold to determine that number.
• The inner diameter of the superheater elements has to be sufficient to allow steam to pass at a typical upper velocity of 10m/s: much smaller than that and the elements may be too big; much bigger than that and the elements are too small.
• The difference between the inner diameter and the outer diameter gives the wall thickness, which needs to be sufficient to withstand the pressure of the steam at the highest temperature to which the elements are to be exposed allowing for any scaling-up that might occur over time, which is a function of the strength of the material selected, the feedwater treatment regime and the blowdown regime.
• The maximum number of superheater elements is constrained by the materials of construction and the pitch between the tube holes in the superheater headers allowing for several refits during the life of the boiler; if the boiler is intending to last beyond a single insurance assessment period then this must be taken into account in the design of the superheater headers.
• The superheater header design may be constrained by the boiler structure.

The rest can be seen at the original poster's offices and the original poster's plant.

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