| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 155701 | Chemical Engineering Science | 2012 | 7 Pages |
The availability of acid dew-point correlations (for flue gases containing the precursors of sulfuric-, nitric-, hydrochloric acids, etc.) that directly relate Tw,dpTw,dp to the participating species partial pressures (e.g., Banchero and Verhoff, 1975 and Verhoff and Banchero, 1974) without the explicit need for liquid phase thermodynamic properties has led to their popularity for preliminary design estimates of onset surface temperatures for corrosive deposits. Despite the fact that these correlations cannot be used when either or both precursor partial pressures become too small, when they are invoked within their intended domains of validity, we show here that they can be conveniently used to not only quickly estimate acid dew-point temperatures in the presence of unavoidable gas phase precursor species Soret separation effects, but also to provide preliminary estimates of the surface temperatures, Tw,AMOTw,AMO, associated with the local onset of acid mists in the vicinity of cooled surfaces. Our present simple theoretical/numerical methods are illustrated for the most familiar case of sulfuric acid deposits. While we indicate that increased accuracy and generality will require a more fundamental approach in which condensate thermodynamic non-ideality is explicitly introduced, we show here that prudent use of these earlier engineering correlations can lead to immediately useful preliminary estimates of both transport-shifted Tw,dp-Tw,dp- and Tw,AMO-valuesTw,AMO-values.
► Ability to predict when corrosive acids condense on energy recovery surfaces. ► Ability to predict when corrosive acid mists form within thermal boundary layers. ► Account taken of systematic shifts due to non-Fickian (Soret-) mass transport. ► Illustrative calculations for the H2SO4+H2O binary system (e.g., SO3 in flue gases). ► Extensions to predict condensate composition, and deal with ternary systems, discussed.
