1 / 39

Drums, Vessels, & Storage Tanks

Drums, Vessels, & Storage Tanks. Design Considerations. The Equipment List. Vessels, including Reactors Towers Storage Tanks See User Added Equipment. Maximum Allowable Working Pressure (MAWP)- Actual Metal Thickness Used. Fab Shop.

gwendolyn-hogan
Download Presentation

Drums, Vessels, & Storage Tanks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Drums, Vessels, & Storage Tanks Design Considerations

  2. The Equipment List • Vessels, including Reactors • Towers • Storage Tanks • See User Added Equipment

  3. Maximum Allowable Working Pressure (MAWP)- Actual Metal Thickness Used Fab Shop Design Pressure (Relief Valve Set Pressures, Minimum Required Metal Thickness) Process Engineer Maximum Op. Pressure (Controls, S/U , S/D ...) Normal Op. Pressure (Pro II) Vessels - General • Wall Thickness • determined by required pressure • Process Engineer Determines Design Pressure • See Web Notes

  4. Design Pressure • Excessive design pressure causes equipment to be more expensive than is required t = metal thickness, P = Design Pressure Cc = Corrosion Allowance, Ej = Joint Efficiency 5

  5. Vessels - General

  6. General - Design Temperatures • Allowable Stress Values are dependant on Temperature • Temperature at Design Pressure must be stated • Materials become brittle below certain temperatures - minimum design metal temperature

  7. Reflux Drums

  8. Reflux Drum Sizing • Assume a length to diameter Ratio of 3 • Therefore: • Solve for diameter

  9. Reflux Drums (PRO II) • The Volume - Method 1 • Determine Liquid Rate Into the Drum - Careful of your simulator flows • Give 20% excess for start-up • Size for 5 to 10 min @ half full

  10. General - Tanks/Vessels • Method 2 - Hold Up Time (at half full) • 2 to 32 minutes depending on quality of control for each outgoing stream • 5 to 10 minutes is sufficient with modern control systems to handle minor upsets • 30 minutes provides a 99% probability that an operator can determine cause of failure • Engineering Judgement ! 11

  11. Vessels - Safety • Vessel that can be isolated require Relief Valves

  12. Vessels - Relief Valves

  13. Vessels (Reactor) • Sized on processing requirements • Agitated vessels usually have L/D ~ 1 • Non agitated L/D ~ 3 • Superficial velocities important? • Fluidization of contents? • Internal coils, external jackets

  14. Vessels (Reactor) • Plug Flow Reactor Issues • Residence Time / Volume - Pro II • Pressure Drop - packed beds - ergun eqt. (Perry’s) • Back Mixing - Testing, CFD - L/D > 5

  15. General - Tanks/Vessels • Horizontal vs. Vertical • Vertical preferred when: • small liquid load • limited plot space • ease of level control is desired • Horizontal preferred when: • large liquid loads are involved, consequently hold-up will set the size • three phases are present 12

  16. 36” + 1/2 feed nozzle OD (48” min) Mesh Entrainment Separator 12” + 1/2 feed nozzle OD (18” min) Vertical Separator General - Tanks/Vessels 13

  17. General - Tanks/Vessels • Liquid levels • norm liq level at 50% • show low liq level at 25% • provide low, low liq level for pump shut offs • Vapour Disengagement (vertical flash vessel) • Diameter Calcs; v = ft/ sec; density = lb/ft3 • No Mesh k=0.16; Mesh Separators k = 0.35 • Length to Diameter Ratio - 3 to 5 for Economical Design - but not a necessity 13

  18. Mesh Separator

  19. Codes Stds’ - ASME • ASME - American Society of Mechanical Engineers • Section I - Fired Heaters • Section VIII - Pressure Vessels • Other Sections (Plastic / Fiberglass / nuclear) 14

  20. Auxiliaries • Manholes / inspection ports • ASME Code has minimum requirements for these based on vessel size - See Section 8 UG-46 • Nozzles - velocities • max v=100/ , ft/sec • min v= 60/ , ft/sec • Non-tangential inlet for easier level control 14

  21. Auxiliaries • Thermowells • Steamouts • Maintenance blinds • Drains • Level Gauges

  22. Towers • Diameter - Pro II • Tray Section Height • Number of Real Trays • Ideal Trays / 0.6 * 1.1 • Height = 24” x # trays • Remember - subtract condenser & Reboiler • Additional Height for Reboiler • Additional Height for V/L Separation at top • Double Tray Spacing at Feed

  23. Towers 4 ft Double Tray Space 6 ft

  24. Towers - Diag

  25. Valve Trays

  26. Towers • Tray Flows VIDEO

  27. Towers • Packing • Random • Structured

  28. Field Fabricated Vessels/Tanks • Fabricate in field if shipping is impractical • Typically large atmospheric tanks • Tank Types • Cone, • floating roof, • sphere, • hemispheroid • Codes & Std’s – API, ASME

  29. Storage Tanks Design Pressures < 15 psig

  30. Tank Farm

  31. Tanks - Cone Roof • Typically Design Pressure < 2 psig, but usually 2.5 Inches Water gauge • Ensure Vapour Pressure of Liquid is sufficiently low (suggest < half D.P.)

  32. Storage Tanks - Cone Roof Conservation Vent

  33. Tanks - Floating Roof • Suitable for fluids with vapour pressures up to about 8 psig Floating Roof pontoons Edge Seal

  34. Tanks - Spheres • Suitable for Design Pressures of • 2 to 15 psig • 30 to 220 psig (Ludwig)

  35. Tanks - Bullet Tanks • Any Pressure

  36. 36” + 1/2 feed nozzle OD (48” min) 12” + 1/2 feed nozzle OD (18” min) Vap Rate: Liq Rate: Vap Density: Liq Density: Workshop • Size the Flasher • Size 50% Liq Hold-up for 10 min

  37. end

  38. questions • types of trays • horiz vs vertical reactors • lifter roof? • Margin of error on flows

  39. Reflux Drums (HYSYS) • The Volume • Liquid Rate Into the Drum - Careful of your simulator flows • Give 20% excess for start-up

More Related