ASME UHX-12 U-Tubesheets

ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 1 02.12.2004 Calculation according to UHX-12, ASME BPVC 2004 CONTENTS Input values for the calculation of tubesheets.......................................................................................................... 2 Description of input values.................................................................................................................................. 2 Screen mask of the tubesheet calculation: ........................................................................................................... 4 PART UHX RULES FOR SHELL AND TUBE HEAT EXCHANGERS ............................................................. 6 UHX-1 SCOPE............................................................................................................................................. 6 UHX-2 MATERIALS AND METHODS OF FABRICATION................................................................... 6 UHX-3 TERMINOLOGY.................................................................................................................................. 6 UHX-3.1 U-Tube Heat Exchanger. ................................................................................................................. 6 UHX-3.2 Fixed Tubesheet Heat Exchanger. ................................................................................................... 6 UHX-3.3 Floating Tubesheet Heat Exchanger. ............................................................................................... 6 UHX-4 DESIGN ................................................................................................................................................. 6 UHX-10 GENERAL CONDITIONS OF APPLICABILITY FOR TUBESHEETS..................................... 7 UHX-11 TUBESHEET CHARACTERISTICS ............................................................................................ 8 UHX-11. 1 Scope. ........................................................................................................................................... 8 UHX-11.2 Conditions of Applicability. .......................................................................................................... 8 UHX-12 RULES FOR THE DESIGN OF U-TUBE TUBESHEETS......................................................... 12 UHX-12.1 Scope. .......................................................................................................................................... 12 UHX-12.2 Conditions of Applicability. ........................................................................................................ 13 UHX-12.3 Nomenclature. ............................................................................................................................. 13 UHX-12.4 Design Considerations ................................................................................................................. 14 UHX-12.5 Calculation Procedure.................................................................................................................. 15 TABLE 2-5.1: GASKET MATERIALS AND CONTACT FACINGS1........................................................... 19 TABLE 2.5-2 EFFECTIVE GASKET WIDTH................................................................................................ 21 UHX-20 EXAMPLES ................................................................................................................................. 22 UHX-20.1 Examples of UHX-12 for U-Tube Tube-sheets ........................................................................... 22 UHX-20.1.1 Example 1: Tubesheet Integral With Shell and Channel ...................................................... 22 UHX-20.1.2 Example 2: Tubesheet Gasketed with Shell and Channel..................................................... 24 UHX-20.1.3 Example 3: Tubesheet Gasketed with Shell and Channel..................................................... 25 UHX-20.1.4 Example 4: Tubesheet Gasketed With Shell and Integral With Channel, Extended as a Flange ........................................................................................................................................................ 26 Calculation of examples 20.1.1 – 20.1.4 ........................................................................................................... 29 Figures ............................................................................................................................................................... 50 ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 2 02.12.2004 Input values for the calculation of tubesheets The first section describes the input values shortly. The second section shows an example of the input mask for the calculation. Description of input values 1. Configuration; The configurations are illustrated in Fig. UHX-12.1. The next text field below on the screen explains the specified configuration. 2. Internal operation pressure shell side; Shell side internal design pressure (see UG-21). For shell side vacuum use a negative value for Ps. This value is used for load case <> 2 (different from testing). 3. Internal operation pressure tube side; Tube side internal design pressure (see UG-21). For shell side vacuum use a negative value for Pt. This value is used for load case <> 2 (different from testing). 4. Internal test pressure shell side; Shell side internal test pressure (see UG-21). This value is used for the test load case with material properties at room temperature (20°C), when load case = 2 is specified. 5. Internal test pressure tube side; Tube side internal test pressure (see UG-21). This value is used for the test load with material properties at room temperature (20°C), when load case = 2 is specified. 6. Load case; The following values can be selected: 1 = Operation, 2 = Test at 20°C, 3 = other. Load case 3 uses operation pressure and temperature for the calculation and allows overwriting of the next text field below on the screen mask, which explains the selected load case. 7. Calculation case UHX12.4(a); According UHX-12.4 the following calculation cases must be considered: 1. tube side pressure, 2. Shell side pressure and 3. Tube and shell side pressure acting simultaneously. 8. Material tubesheet; The material code for the tubesheet. Example: S31600-SA-240-316 — contains the UNS-number S31600, the specification SA-240 and material 316. 9. Material shell (Type abc); The material code for the shell is only necessary for configurations a, b, c, with an integral joint between shell and tubesheet. 10. Material tubes, Material code of the tubesheet. 11. Mat. channel (Type aef); Material code for the channel, only necessary for types a,e,f with integral connected channels. 12. Link modules for calculation cases 1-3 (Y/N)? This option allows to link two additional modules for the calculation cases 2 and 3 specified above. All input values are linked between the modules. Values that are changed in one module will be changed in the linked modules also. 13. Temperatr. Temperature of the corresponding materials for tubesheet, shell, tubes and channel. 14. Thickness The thickness of the materials, which are necessary for the specified configuration. Values for shell and/or channel are only necessary in the case of an integral connection. 15. Outs.diam. Outside diameter of tubesheet, shell, tubes and channel. Values for shell and/or channel are only necessary in the case of an integral connection. 16. Strength This is the allowable stress for operation temperature in the case of ASME materials. 17. Safety fac. The safety factor is usually = 1 for ASME material. 18. E-module. Modulus of elasticity at operation temperature. 19. Allow. c1 Wall manufacturing allowance. 20. Corr.all.c2 Corrosion allowance. 21. Figure . The external pressure chart according to ASME 22. Therm.exp. Coefficient of thermal expansion. 23. Yield str. Yield strength of the material, necessary for primary and secondary stress. 24. Limit temp. Limit temperature for time dependent (creep) material properties. 25. All.Stress*) Allowable stress (Can be overwritten by the user) 26. Pr.+sec.st*) Primary and secondary stress (Can be overwritten by the user) 27. Strength (20°C) Allowable stress at room temperature (20°C) for ASME materials. 28. Safety fac. (20°C) Usually = 1 for ASME materials. 29. E-module (20°C) Modulus of elasticity at room temperature. 30. Yield str. (20°C) Yield strength at room temperature. 31. Tensile str. (20°C) Tensile strength at room temperature (20°C) 32. Tube joint (1=expanded, 2=backside-welded ) Type of tube joint as defined in Fig. UHX-11.1 33. Tube hole diameter (only for backside-welded tubes); This is the diameter d defined in Fig. UHX-11.1 ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 3 02.12.2004 34. Tube hole pattern (1=Triangle, 2=Square); Specification of the tube hole pattern is necessary for Fig. UHX-11.3. 35. Mean distance from the plate center to the outermost tube hole centers; radius r0 in Fig. UHX-11.1(a) 36. Tube hole pitch (Center distance); Distance p of tube centers. 37. Expanded length of tube in tubesheet ltx; Variable ltx illustrated in Fig. UHX-11.1(b) 38. Untubed area UL1*LL1+UL2*LL2...; This variable is shown in Fig.UHX11.2. 39. Depth of pass partition groove; Variable hg illustrated in Fig. UHX-11.1c 40. Length ratio of tube expansion; Ratio ltx/h 41. Mean contact diameter tubesheet-flange; The mean contact diameter for tubesheets extende as flange (Type c, f in in Fig. UHX-12.1c, f. 42. Outside diameter of contact area Gca; Necessary for gasketed channel ( Type b,c,d ) 43. Inside diameter of contact area; Inside diameter of channel gasket Gci ( Type b,c,d ) 44. Basic seating width acc.; Variable b0c listed in App.2 Table 2-5.2 ; ( Type b,c,d ) 45. Diameter of gasket force; Variable Gc illustrated in App.2 at the end of Table 2-5.2 ( Type b,c,d ) 46. Outside diameter of contact area; Gsa (Type d,e,f) 47. Inside diameter of contact area; Gsi (Type d,e,f) 48. Basic seating width; b0s acc. App.2 Table 2-5.2 b0s (Type d,e,f) 49. Diameter of gasket force; Gs acc. App.2 Table 2-5.2 (Type d,e,f) 50. Poisson's ratio, channel; The default value is 0.3 51. Poisson's ratio, shell; The default value is 0.3 52. Bolt circle diameter; Variable C for tubesheets extended as flange (Type bcdef) 53. Bolt force installation, channel flange; Wc calculated in module AFL (Type bcd) 54. Bolt force installation, shell flange; Ws calculated in module AFL (Type def) ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik L Screen mask of the tubesheet calculation: 0 Configuration of the tubesheet (a, b, ..., f) Type (a-f) Internal operation pressure shell side Ps psi Internal operation pressure tube side Pt psi Internal test pressure shell side Psp psi Internal test pressure tube side Ptp psi Load case (1=Operation, 2=Test at 20°C, 3=other) *) Calculation case UHX12.4(a) (1: Ps=0, 2: Pt=0, 3:Differ.) (1-3) Material tubesheet Material shell (Type abc) Material tubes Mat. channel (Type aef) Link modules for calculation cases 1-3 (Y/N)? No (Y/N) Operation Tubesheet Shell Tubes Channel Temperatr. °C °C °C °F Thickness in in in in Outs.diam. in in in in Strength psi psi psi psi Safety fac. E-module psi psi psi psi Allow. c1 in in in in Corr.all.c2 in in in in Figure Therm.exp. 1E-6/°F 1E-6/°F 1E-6/°F 1E-6/°F Yield str. psi psi psi psi Limit temp. °C °C °C °C All.Stress*) MPa MPa MPa psi Pr.+sec.st*) psi psi psi psi *)can be overwritten by the user for load case ≥ 3 Test 20°C Tubesheet Shell Tubes Channel Strength psi psi psi psi Safety fac. E-module psi psi psi psi Yield str. psi psi psi psi Tensile str. psi psi psi psi additional specifications for geometry and loading Tubesheet Tube joint (1=expanded, 2=backside-welded) (1, 2) Tube hole diameter (only for backside-welded tubes) dAH in Tube hole pattern (1=Triangle, 2=Square) (1, 2) Mean distance from the plate center to the outermost tube hole centers r0T in Tube hole pitch (Center distance) p in Expanded length of tube in tubesheet ltx in Untubed area UL1*LL1+UL2*LL2... Fig.UHX11.2 AL in² Depth of pass partition groove hg in Length ratio of tube expansion ltx/h ρ Mean contact diameter tubesheet-flange (Type cf) G1 in U-Tubesheet Heat Exchanger according to ASME-UHX-11 auterbach Verfahrenstechnik 4 02.12.2004 ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 5 02.12.2004 1 Chanel gasket for Type b,c,d Outside diameter of contact area Gca in Inside diameter of contact area Gci in Basic seating width acc. App.2 Table 2-5.1&2 b0c in Diameter of gasket force acc. App.2 Table 2-5.2 Gc in Shell gasket for Type d,e,f Outside diameter of contact area Gsa in Inside diameter of contact area Gsi in Basic seating width acc. App.2 Table 2-5.1&2 b0s in Diameter of gasket force acc. App.2 Table 2-5.2 Gs in Poisson's ratio, channel νC 0.3 Poisson's ratio, shell νS 0.3 Bolt circle diameter (Type bcdef) C in Bolt force installation, channel flange (Type bcd) Wc lbf Bolt force installation, shell flange (Typ def) Ws lbf *)Bolt forces from module AFL Results acc. to UHX-12 Maximum bolt force (Type d) Wmax lbf Channel thickness without allowances tc in Shell thickness withtout allowances ts in Inside diameter of channel, corroded (Type ade ) Dc in Inside diameter of shell, corroded (Type abcd) Ds in Recommended initial tubesheet thickness, UHX-12.4 hin in Tubesheet thickness without allowances > hin h in Step 1 acc. to UHX 12.5 Equivalent diameter of outer tube limit circle D0 in Basic ligament efficiency for shear µ Effective tubeside pass partition groove depth hg' in Step 2 Ratio Ds/D0 (Type abc) or Gs/D0 (Type def) ρS Ratio Dc/D0 (Type aef) or Gc/D0 (Type bcd) ρC Tubesheet rim moment due to Ps and Pt MTS lbf Step 3 Effective mod. elasticity tubesheet (Fig.UHX-11.2&3) E* psi Effective Poisson's ratio of tubesheet ν* Effective tube pitch p* in Effective ligament efficiency for bending µ* Effective tube hole diameter d* in Step 4 Coefficient for shell pressure, Type abc δS in^3/lbf Coefficient for moment of shell ωS in² Coefficient for channel pressure, Type aef δc in^3/lbf Coefficient for moment of channel ωC in² step 5 Diameter ratio = A/D0 K Coefficient F Step 6 Rim moment M* lbf Step 7 Maximum bending moment at periphery Mp lbf Moment at the tubesheet center M0 lbf Step 8 Strength condition for the bending stress in the tubesheet: Sig = psi < 2* SigB = psi ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 6 02.12.2004 PART UHX RULES FOR SHELL AND TUBE HEAT EXCHANGERS This section contains the formulas used in the calculation of tubesheets according to ASME Boiler and Pressure Vessel Code. The formulas below are adapted for programming, in accordance with the original, which is available from ASME (ASME, New York, 2004, internet: http:\\www.asme.org). The extract includes only necessary sections for the calculation program. Since not all definitions are complete and eventually not all typing errors are eliminated, the user may consult the original ASME-standards for a complete overview on the design of heat exchangers. UHX-1 SCOPE The rules in UHX cover the minimum requirements for design, fabrication and inspection of shell and tube heat exchangers. UHX-2 MATERIALS AND METHODS OF FABRICATION Materials and methods of fabrication of heat exchangers shall be in accordance with Subsections A, B, and C. UHX-3 TERMINOLOGY UHX-3.1 U-Tube Heat Exchanger. Heat exchanger with one stationary tubesheet attached to the shell and channel. The heat exchanger contains a bundle of U-tubes attached to the tubesheet [see Fig. UHX-3, sketch (a)]. UHX-3.2 Fixed Tubesheet Heat Exchanger. Heat exchanger with two stationary tubesheets, each attached to the shell and channel. The heat exchanger contains a bundle of straight tubes connecting both tubesheets [see Fig. UHX-3, sketch (b)]. UHX-3.3 Floating Tubesheet Heat Exchanger. Heat exchanger with one stationary tubesheet attached to the shell and channel, and one floating tubesheet that can move axially. The heat exchanger contains a bundle of straight tubes connecting both tubesheets [see Fig. UHX-3, sketch (c)]. UHX-4 DESIGN UHX-4(a) The design of all components shall be in accordance with the applicable rules of Subsection A, Mandatory Appendices, and this Part. UHX-4(b) The design of a bolted flat cover where the cover bears against a gasket at the pass partition shall consider the effects of deflection. UHX-4(c) The design of flanges shall consider the effects of pass partition gasketing in determining the minimum required bolt loads, Wml and Wm2, of Appendix 2. When the tubesheet is gasketed between the shell and channel flanges, the shell and channel flange bolt loads are identical and shall be treated as flange pairs in accordance with Appendix 2. UHX-4(d) Distribution and vapor belts where the shell is not continuous across the belt shall be designed in accordance with UHX-17. UHX-4(e) Requirements for tubes shall be as follows. UHX-4(e)(1) The required wall thickness of tubes under internal and external pressure shall be in accordance withJJG-31. UHX-4(e)(2) the allowable axial tube stresses in fixed and floating tubesheet heat exchangers given in this Part (UHX-13 and UHX-14) supercede the requirements of UG-23. UHX-4(e)(3) The thickness of U-tubes after forming shall not be less than the design thickness. UHX-4(f) Rules for U-tube heat exchangers are covered in UHX-12. ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 7 02.12.2004 UHX-4(g) Rules for fixed tubesheet heat exchangers are covered in UHX-13. UHX-4(h) Rules for floating tubesheet heat exchangers are covered in UHX-14. UHX-10 GENERAL CONDITIONS OF APPLICABILITY FOR TUBESHEETS UHX-10(a) The tubesheet shall be flat, circular, and of uniform thickness. The tubesheet shall be uniformly perforated over a nominally circular area, in either equilateral triangular or square patterns. However, un- tubed lanes for pass partitions are permitted. UHX-10(b) The tube side and shell side pressures are assumed to be uniform. These rules do not cover weight loadings or pressure drop. When these conditions of applicability are not satisfied, see U-2(g). 3(a) U-Tube Heat Exchanger 3(b) Fixed Tubesheet Heat Exchanger 3(c) Floating Tubesheet Heat Exchanger Fig. UHX-3 TERMINOLOGY OF HEAT EXCHANGER COMPONENTS (1) Channel cover (bolted flat cover) (2) Channel (3) Channel flange (4) Pass partition (6) Shell flange (7) Tubes (8) Shell (9) Baffles or support plates (11) Floating tubesheet (12) Floating head (13) Floating head flange (14) Shell cover ASME UHX-12 U-Tubesheets / U-Rohr Wärmetauscherböden Lauterbach Verfahrenstechnik Lauterbach Verfahrenstechnik 8 02.12.2004 (5) Stationary tubesheet (10) Floating head backing device (15) Expansion bellows (16) Distribution or vapor belt UHX-11 TUBESHEET CHARACTERISTICS UHX-11. 1 Scope. These rules cover the determination of the ligament efficiencies, effective depth of the tube side pass partition groove, and effective elastic constants to be used in the calculatio