pdp 09 towers p12

Process Design Practices Towers Page : By : CK Date : Dec 09 Copyright c This data is confidential and shall not be disclosed or reproduced in any manner without written permission 9.3 Tower Layout • Layout and dimensions are largely from Henry Kister, “Distillation Design” and “Distillation Operation”. • Typically many layouts work, use the simplest, proven design. • Refer to “Vessels” section for other nozzle and flange requirements. 9.3.1 Inlet Nozzles/Piping • Nozzle typically same size as connecting pipe. • Enlarge nozzle to meet velocity criteria: – ρv 2 ≤ 1600 - 3600 (lb/ft 3 × ft 2 /s 2 ) – Change pipe size 10 pipe diameters before nozzle • Feeds should distribute fluid evenly to all passes. • Never direct feed towards or into the liquid phase (downcomers, traps or boot), except to quench surge volume with cold liquid. • Vapour feed usually doesn’t have a distributor, except to prevent corrosion/erosion. • Feed outlet velocity from distributor pipe or holes/slots: Liquid 2-Phase (ft/s) (psi) Minimum 2-3 0.25 To prevent vibration Maximum 4-6 0.5 To reduce turbulance • Bottom tray must have side downcomers, to reduce nr of reboiler return nozzles. 9.3.2 Outlet Nozzles/Piping • Typical surge time in towers is 2-5 minutes on total flow (net+reboil/pumparound), distance rounded up to standard float size. • Outlet nozzles are sized for pump suction (0.2 psi/100ft) or self venting flow (v<1 ft/s). • Typically vortex breaker is provided at vessel bottom, but not side draws. Vortex breaker not necessary for self venting flow (Sloley, CEP, Jun 1998). • Nozzle bottom must be flush with tray (to drain tray completely). 9-12

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PDP 09 Towers P12

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Process Design PracticesTowers

Page :By : CK

Date : Dec 09

Copyright c This data is confidential and shall not be disclosed or reproduced in any manner without written permission

9.3 Tower Layout

Layout and dimensions are largely from Henry Kister, Distillation Design andDistillation Operation.

Typically many layouts work, use the simplest, proven design. Refer to Vessels section for other nozzle and flange requirements.

9.3.1 Inlet Nozzles/Piping

Nozzle typically same size as connecting pipe. Enlarge nozzle to meet velocity criteria:

v2 1600 3600 (lb/ft3 ft2/s2) Change pipe size 10 pipe diameters before nozzle

Feeds should distribute fluid evenly to all passes. Never direct feed towards or into the liquid phase (downcomers, traps or boot),except to quench surge volume with cold liquid.

Vapour feed usually doesnt have a distributor, except to prevent corrosion/erosion. Feed outlet velocity from distributor pipe or holes/slots:

Liquid 2-Phase(ft/s) (psi)

Minimum 2-3 0.25 To prevent vibrationMaximum 4-6 0.5 To reduce turbulance

Bottom tray must have side downcomers, to reduce nr of reboiler return nozzles.

9.3.2 Outlet Nozzles/Piping

Typical surge time in towers is 2-5 minutes on total flow (net+reboil/pumparound),distance rounded up to standard float size.

Outlet nozzles are sized for pump suction (0.2 psi/100ft) or self venting flow (v