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Quotes - Engineering - SalesCondensing and Heat Recovery
A condenser that meets its calculated duty and fails in service usually fails for one of three reasons: gas that was not vented, condensate that could not leave, or a condensing curve that was treated as a single temperature. All three are design questions rather than surface area questions, and all three are cheaper to resolve before purchase.
What Decides the Design
Vapor rate and composition including the noncondensable fraction, operating pressure, the coolant available, and the pressure drop the process can tolerate. Then the arrangement: where the unit sits relative to what drains into it, how gas is vented, and how far the duty turns down. Orientation matters more here than on any other duty because gravity governs the condensate film.
Why U-Tube Suits Condensing
Condensing produces large temperature differences and abrupt transients on startup and trip, which a U-bundle absorbs without an expansion joint. The removable bundle matters too, because vapor is frequently the dirtier side and it usually runs shell-side on large condensers. For deeper coverage of condensing specifically, our sister site VaporCondensers.com addresses this duty in detail.
Because it accumulates at the condensing surface and forms a blanket the vapor has to diffuse through. Even a small percentage can reduce the condensing coefficient dramatically. Venting is not an accessory on a condenser; it is part of the design.
Shell side for large vapor volumes and low pressure drop, which is most large condensers. Tube side for hygienic duty needing drainability, for reflux service where condensate runs back against rising vapor, and for high-pressure vapor.
Substantially, because gravity governs how the condensate film behaves. A condenser rated horizontally and installed vertically will not perform as calculated. Orientation has to be fixed before rating, not after.
For a multicomponent vapor, condensation happens across a temperature range rather than at a single point. Treating it as one temperature overestimates the driving force and undersizes the exchanger. The rating needs the curve, not just the dew point.
Yes, mounted vertically, so condensate runs back down the same passage the vapor came up. That duty exercises the exchanger thermally, which is another argument for a bundle that expands freely.
