The engineering task
A process vapour must be fully condensed at a specified pressure and may also require subcooling. Non-condensable gases reduce heat transfer and must be removed at a suitable location. Vapour-side pressure drop is critical because it directly changes condensation temperature and available temperature difference.
In addition to normal internal pressure, the shell often requires design for full vacuum or a vacuum upset. Loss of cooling water, blocked condensate outlet and pressurisation of one side while the other is depressurised must be evaluated as separate cases.
Required design data
- Vapour composition, flow rate and condensing pressure
- Non-condensable fraction and required subcooling
- Cooling-water state and allowable temperature rise
- Vacuum, shutdown and pressure-equalisation cases
Technical solution approach
Determine phase equilibrium and duty
Balance condensing pressure, saturation temperature, latent heat and sensible subcooling consistently.
Model the condensing zones
Treat desuperheating, condensation and subcooling separately because coefficients and temperature differences differ.
Iterate area and pressure drop
Match tube layout, passes and cooling-water flow to duty and pressure-drop limits, feeding vapour pressure loss back into saturation temperature.
Check venting and condensate drainage
Non-condensables must not accumulate in poorly swept zones, and condensate must drain without backup and with sufficient static head.
Verify vacuum resistance
Check shell, heads and any stiffening rings for external pressure; define overpressure and vacuum protection separately.
Expected deliverables
Suitable SOL ALPHA modules
The modules form a technically plausible toolchain. Their final selection and sequence will be confirmed during the later calculation against the applicable code and project conditions.