Engr Butch G Bataller ChE 192 Process Equipment Design September 20 2011 Pressure Vessels Closed vessel having an internal pressure between 15 psig to 3000 psig ASME Boiler and Pressure Vessel Code contains rules for the ID: 1044700
Download Presentation The PPT/PDF document "PRESSURE VESSELS DESIGN PROCEDURES" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. PRESSURE VESSELSDESIGN PROCEDURESEngr. Butch G. Bataller ChE 192 Process Equipment DesignSeptember 20, 2011
2. Pressure VesselsClosed vessel having an internal pressure between 15 psig to 3000 psig ASME Boiler and Pressure Vessel Code contains rules for the design, fabrication and inspection of boilers and pressure vesselsMay include reflux drum, storage tanks, heat exchangers, chemical reactors, distillation columns, absorption tower, stripping columns, etc.
3. PV Design: Shell ThicknessIn general, the minimum wall thickness of welded metal plates subject to pressure, excluding corrosion allowances, should not be less than 2.4 mm a function of the ultimate tensile strength of the metal at operating temperature, operating pressure, vessel diameter and welding joint efficiency
4. PV Design: Shell ThicknessFor a cylinder based on Inside diameterwhere tp = shell thickness required (inch) [m] P = Internal design gauge pressure (psig) [kN/m2] R = Inside Radius (inch) [m] S = Allowable stress (psi) [kN/m2] E = Joint efficiency factor (Table 6-2) C = Corrosion allowance (inch) [m]
5. PV Design: Shell ThicknessFor a cylinder based on Inside diameterProvided that tp less than or equal to orPressure is less than or equal to 0.385 SE (Jawad and Farr, 1988)
6. PV Design: Shell ThicknessFor a cylinder based on Outside diameterwhere tp = shell thickness required (inch) [m] P = Internal gauge pressure (psig) [kN/m2] R = outside Radius (inch) [m] S = Allowable stress (psi) [kN/m2] E = Joint efficiency factor (Table 6-2) C = Corrosion allowance (inch) [m]
7. PV Design: Shell ThicknessAllowance for Vertical PVFor 10>( L/Di)2/ Pd>1.34:tv = tp[0.75 + 0.22E( L/Di)2/Pd] If (L/Di)2/Pd < 1.34, tv=tp
8. PV Design: Shell ThicknessCorrosion Allowance1/8 inch for noncorrosive conditions¼ for corrosive environments.ts = tV + tc
9. PV Design: Shell ThicknessFor Vacuum Vesselswhere Pc = Collapsing pressure (psi) Te = Thickness to withstand external pressure (inch) Do = Outside diameter (inch) Em = Material’s modulus of elasticity [Table 6-4]** Te must be high enough so that Pc is five times greater than the difference between atmospheric pressure and design vacuum pressure
10. PV Design: Shell ThicknessFor Vacuum Vessels (alternate)tE=1.3(PdL/EmDo)4tEC=L(0.18Di-2.2 )x 10 -5- 0.19 tV = tE + tEC where Pd = internal design gauge pressure (psi) Te = Thickness to withstand external pressure (inch) Do = Outside diameter (inch) Em = Material’s modulus of elasticity
11. PV Design: Shell ThicknessSpherical Vesselswhere P = internal design gauge pressure (psig) R = Inside Radius (inch) tp = Minimum required thickness (inch) E = Lowest joint efficiency S = Max allowable stress (psi)
12. Design Temperaturedesign temperature may be equal to operating temperatue plus 50oF
13. Design PressureOperating Pressure ,Po (psig)Design Pressure ,Pd (psig)0 -5 1010 – 1,000P= exp{0.60608 + 0.91615[ln Po] + 0.0015655 [ ln Po ]2 }1,000 +1.1Po
14. Material of ConstructionCarbon Steel >>> Non-corrosive environment, T= (-20 to 650 OF)Low Alloy Steel >>> Non-corrosive environment, T= (650 to 900 OF)Stainless Steel 300 Series >>> can be used up to 1,500 OF
15. Modulus of Elasticity ValuesTemperature (ºF)Psi x 106Carbon SteelLow-alloy Steel-2030.230.220029.529.540028.328.665026.027.0700-26.6800-25.7900-24.5
16. Recommended Stress Values Joint efficienciesRecommended stress valuesMetalTemp., ºCS, kPaFor double-welded butt joints If fully radiographed = 1.0 If spot-examined = 0.85 If not radiographed = 0.70In general, for spot examined If electric resistance weld = 0.85 If lap-welded = 0.80 If single-butt-welded = 0.60Carbon steel(SA-285, Gr. C)Low-alloy steelfor resistance toH2 and H2S(SA-387, Gr. 12C1.1)High-tensile steelfor heavy-wallvessels(SA-302, Gr.B)High-alloy steelfor cladding andcorrosion resistanceStainless 304(SA-240)Stainless 316(SA-240)Nonferrous metals Copper (SB-11) Aluminum(SB-209, 1100-0)-29 to 343399454-29 to 427510565649-29 to 399454510538-29343427538-29345427538382043820494,50082,70057,20094,50075,80034,5006,900137,900115,80069,00042,750128,90077,20072,40066,900128,90079,30075,80073,10046,20020,70015,9006,900
17. Sample ProblemDetermine the thickness of a 5 meter inside diameter spherical tank for handling a corrosive liquid at a design pressure and temperature of 300KPa and 27F, respectively. The material of construction is made of carbon steel.
18. Sample ProblemIf the height of the tank is 35m, what is the thickness of the tank incorporating earthquake and wind load?What if the given pressure is an operating pressure?
19. Types of Welded JointsButt jointCorner jointEdge jointLap jointT joint
20. Square Butt JointsUsed to butt weld light sheet metal1/16 to 3/16 thick metal.
21. Beveled Butt JointsUsed to butt weld heavier pieces of metal together3/8 to ½ inch metal can welded using a single V or U joint½ Inch metal and up can be welded using a double V or U joint
22. Beveled Cont.
23. Corner JointsUsed to join to pieces of metal that are approximately right angles to each otherClosed corner joint is used on light sheet metal were strength is not required at the jointHalf open corner joint is used on heavier metal when welding can only be done on one side. Used when load is not severe.
24. Corner Cont.Open corner joint is used on heavy material. It is the strongest of the corner jointsCorner joints on heavy material are welded on both sides The outside first then reinforced on the inside
25. Corners Cont.
26. Edge JointsUsed to join two parallel or nearly parallel pieces of metal (0.25 in thick or less). Not very strong.Used mainly to join edges of sheet metal, reinforce flanges of I beams, and mufflers.
27. Lap JointsUsed to join two overlapping pieces of metalSingle lap joint welded from one sideSingle lap joint welded from two sides develops full strengthOff set lap joint is used when two pieces of metal need to be joined in the same plain.
28. Lap Joints Cont.A- single lap joint, one weld.B- single lap joint, two welds.C- offset lap joint.
29. Tee JointsUsed to join two pieces of metal that are approximately 90 degrees to each other, but the surface of one piece of metal is not in the same plain as the other metal.
30. Tee Joints Cont.A- plain teeB- single beveledC- double beveledD- single JE- double J
31. Types of WeldsFillet weld- basic weld used. Used when joining two pieces of metal without preparing the surface of the metal first.Groove weld- basic weld, used when preparing the metal before welding it into place.
32. Fillet Welds
33. Groove Welds
34.
35. Weld/Joint EfficiencyWelding – heats the metal surrounding the welding area - results in warping, shrinking of the welded areaStress Relieving - required to release locked up localized stress - annealing or hammeringRadiographing - locate weld defects and other structural trouble - welded joints are exposed to x-ray to detect excessive porosity, defective fusion and other defects in the welding process
36. Weld/Joint EfficiencyFor carbon steels (t ≤ 1.25 in)requires only 10% x-ray checkE = 85%For thicker wallsrequires 100% x-ray checkE = 100%
37. Weld/Joint EfficiencyLongitudinal joints should be butt- weldedVessels in lethal application should be butt-welded and fully radiographedAll vessels fabricated on carbon or alloy steel requires post-heat treatmentAll welded joints of cryogenic tanks must be butt welded, postweld heat treated and X- ray examined
38. For double butt joint, the following are the corresponding efficienciesFull radiography 100%Spot radiography 85%No radiography 70 %** when welded joint efficiency is not known, assume a no spot radiography
39. Welded Joints CategoriesCategory A – Longitudinal welded joints within main parts (shells, heads, cones, flat plates, nozzles, and the attachment weld of a hemispherical head to a shell)
40. Welded Joints CategoriesCatefory B – Circumferential welded joints within the main parts (shell, cone, nozzles and the attachment joint between formed heads (elliptical and torispherical) and shell).
41. Welded Joints CategoriesCategory C – welded joints connecting flanges, tubesheets, flat heads to main shell, formed heads, transition in diameter, nozzles, or any welded joint connecting one side plate to another side plate of a flat-sided vesselCategory C – welded joints connecting flanges, tubesheets, flat heads to main shell, to formed heads, to transition in diameter, to nozzles, or any welded joint connecting one side plate to another side plate of a flat-sided vessel
42. Welded Joints CategoriesCategory D – welded joints connecting nozzles to main shells, spheres, formed heads, flat heads, flat-sided vessels.Category C – welded joints connecting flanges, tubesheets, flat heads to main shell, to formed heads, to transition in diameter, to nozzles, or any welded joint connecting one side plate to another side plate of a flat-sided vessel
43. Maximum Allowable Joint Efficiencies for Arc and Gas Welded JointsType No.Joint DescriptionLimitationsJoint CategoryDegree of Radiographic ExaminationabcFullSpotNone(1)Butt joints as attained by double-welding or by other means which will obtain the same quality of deposited weld metal on the inside and outside weld surfaces to agree with the requirements of UW-35; welds using metal backing strips which remain in place are excluded.NoneA, B, C & D1.00.850.70(2)Single welded butt joint with backing strip other than those included in (1)(a) None except as shown in (b) belowA, B, C & D0,900.800.65(b) Circumferential butt joints with one plate offset, see UW-13(c) and Fig. UW-13.1 (k).A, B & C0.900.800.65
44. Type No.Joint DescriptionLimitationsJoint CategoryDegree of Radiographic ExaminationabcFullSpotNone(3)Single-welded butt joint without use of backing stripCircumferential butt joints only. Not over 5/8in. thick and not over 24in outside diameterA, B & CNANA0.60(4)Double full fillet lap joint Double full fillet lap joint longitudinal joints not over 3/8in. thickANANA0.55circumferential joints not over 5/8in. thickB & CNANA0.55
45. Type No.Joint DescriptionLimitationsJoint CategoryDegree of Radiographic ExaminationabcFullSpotNone(5)Single full fillet lap joints with plug welds confirming to UW-17Single full fillet lap joints with plug welds confirming to UW-17(a) Circumferential joints2 for attachment of heads not over 24in. outside diameter to shells not over 1/2in. thick.BNANA0.50(b) Circumferential joint for the attachment to shells of jackets not over 5/8in. in nominal thickness where the distance from the center of the plug weld to the edge of the plate is not less than 1-1/2 times the diameter of the hole for the plug.CNANA0.50(6)Single full fillet lap joints without plug welds(a) For the attachment of heads convex to pressure to shells not over 5/8in. required thickness. only with use of fillet weld on inside of shells, or(b) For attachment of heads having pressure on either side. To shells not over 24in. inside diameter and not over 1/4in. required thickness with fillet weld on outside of head flange only.A & BNANA0.50