T102

STRESS ANALYSIS - FLUE GAS DUCT

Doc No. : TIE/12/KSJ/CAE/02 Rev-A Page- 1 of 11

Project : 150 TPD Sulphuric Acid Plant

STRESS ANALYSIS OF FLUE GAS DUCTS

CLIENT : UROMIA PETROCHEMICAL COMPANY

PROJECT : 150 TPD SULPHURIC ACID PLANT

A 02-OCT-12 FOR APPROVAL KAUTILYA K.S. V.S.

Rev. Issue date DESCRIPTIONPREPARED CHKD. APPR.

BY BY BY




INDEX

1.0 Introduction………………………………………………………………………………………...3

2.0 References………………………………………………………………………………………….3

3.0 Generic Pipe Stress Model Input.……………………………………………………………...3 – 4

4.0 Specifications of Piping Components………………………………………………………….4 – 5

5.0 Methodology…………………………………………………………………………………...6 – 7

6.0 Allowable Nozzle Loads…………………………………………………………………………...8

7.0 Considerations & Assumptions…….………………………………………………………………9

8.0 Results & Discussions…….………………………………………………………………………10

9.0 Recommendations…….…………………………………………………………………………..10

Appendices

A1 Stress Isometric

A2 CAESAR II Model

A3 CAESAR II Report




1.0 INTRODUCTION

This report covers the Stress Analysis of following Flue Gas Ducts:36"-SO2-5001-A10-H-20012"-SO2-5003-A10-H-15012"-SO2-5002-A10-H-150

The analysis has been performed through CAESAR-II Ver-5.10. The applicable Load cases has been presented in Section-5.4 of this report. Refer appendix-A3 for the detailed CAESAR report. The purpose of this analysis is to identify the possible causes of failures and provide recommendations which will help to mitigate these failures.

Used Code & Standards:1.1 ASME B31.3-2004 : Process Piping Code1.2 ASME B36.10M-2004 : Welded & Seamless Wrought Steel Pipe1.3 ASME B16.9-2003 : Factory-Made Wrought Butt-Welded Fittings1.4 EJMA, 9th Ed.: Standards of the Expansion Joint Manufacturers Association, Inc.

2.0 REFERENCES

2.1 10001-PA-DI-A2-EPP-1010 : P&ID2.2 T-210-KSJ-ISO-101 : Isometric Drawing2.3 TIE-SK-01 : Drwg. for Mitered Bends2.4 KSJ-SAU-150-M-DUCT : Ducting Layout2.5 PMS (Piping Material Specifications) released by KSJ2.6 Version 5.10 CAESAR II Applications Guide; 1985-2008 COADE, Inc.

3.0 GENERIC PIPE STRESS MODEL INPUT Operating Condition:Operating Temperature T1 = 480 0COperating Pressure P1 = 0.3 Kg/cm2, g = 0.2942 Bar, g

Design Condition:Design Temperature T2 = 510 0CDesign Pressure P2 = 0.45 Kg/cm2, g = 0.4413 Bar, g

Line Size = 36” NPS & 12” NPSNominal Pipe Thickness tn = 8 mm - 36” NPS

= STD Sch - 12” NPS

Pipe Longitudinal Joint Efficiency Ej = 0.85 Corrosion Allowance CA = 2 mmMechanical Allowance c = NilMill Tolerance MT = 2.5%

Pipe Material = Eqvt. to ASTM A285 Gr. CPipe Density = 7833 Kg/m3




Insulation Material = Mineral WoolInsulation Thickness = 100 mmInsulation Density = 150 Kg/m3

Fluid Specific Gravity ~ 0

4.0 SPECIFICATIONS OF PIPING COMPONENTS

4.1 Fittings:

NPS Description TypeBending Radius

No. of Cuts

36" 900 Elbow Mitered 1.5 D 4

36" 900 Elbow Mitered 1.0 D 4

12” 900 Elbow Butt-Welded (ASME B16.9)

12” Tee Butt-Welded (ASME B16.9)

4.2 Expansion Joints:

Nominal Size = 36” Bellow Effective ID De = 948.5 mmExpansion Joint Type = Gimbal typeMake = Senior FlexonicsStyle = AGMAWP = 3.5 Kg/cm2

No. of Convolutions N = 8Maximum Angular Movement = 100

Bending Stiffness fb = 320 N-m/DegOverall Length = 330 mm (Welded Ends)

267 mm (Flanged Ends)Nominal Size = 12” Bellow Effective ID De = 355.6 mmExpansion Joint Type = Gimbal typeMake = Senior FlexonicsStyle = AGMAWP = 3.5 Kg/cm2

No. of Convolutions N = 8Maximum Angular Movement = 100

Bending Stiffness fb = 78 N-m/DegOverall Length = 330 mm (Welded Ends)

333 mm (Flanged Ends)




4.3 Valves:

4.3.1 Butterfly ValveNominal Size = 36”Mounting Dimension = 950 mmWeight = 3158 N

4.3.1 Butterfly ValveNominal Size = 12”Mounting Dimension = 300 mmWeight = 980 N




5.0 METHODOLOGY

5.1 GeneralThe software used for the stress analysis is Caesar II software package, version 5.10, by Coade Inc. The program analyses flexibility under the assumption that displacement strains will produce proportional stress over a sufficiently wide range. CAESAR automatically calculates the Stress Intensification Factor (SIF) for all fittings (including bends and tees) to accommodate complex stress distribution at fittings.

5.2 Nomenclature5.2.1 Coordinate System: The direction of X, Y, and Z coordinates are as defined below:

X = Positive in south directionY = Positive in vertical upwards directionZ = Positive in west direction

5.2.2 Support Types: Nomenclature for support used in analysis:ANC = Translational and Rotational movements restrained+Y = Vertical downward movement is restrainedGUIDE = Guided support, lateral movements are restrained for horizontal pipe;

horizontal direction movements are restrained for vertical pipe

5.3 Allowable StressesPiping material was considered as Carbon Steel equivalent to ASTM A285 Gr. C. Appendix-A of ASME Code B31.3 provides the value of Allowable Stress for ASTM A285 Gr. C upto 593 0C. Hence, Code Allowable Stresses are as follows:Allowable Stress at Cold condition = Sc = 18300 PsiAllowable Stress at Optg. condition = Sh1 = 6600 PsiAllowable Stress at Design condition = Sh2 = 4500 Psi

5.4 Load Cases

Where:W : Pipe and contents weightT1 : Operating TemperatureP1 : Operating PressureT2 : Design TemperatureP2 : Design PressureOPE : Operating Load CaseSUS : Sustained Load Case

Case No Load Case Type Output1 W + T1 + P1 OPE Disp / Forces2 W + T2 + P2 OPE Disp / Forces3 W + P1 SUS Disp / Force/Stress4 W + P2 SUS Disp / Force/Stress5 L1 - L3 EXP Disp / Force/Stress6 L2 - L4 EXP Disp / Force/Stress




EXP : Displacement Stress Range Load Case5.5 CAESAR Output

Flexibility Analysis has been performed as per the guidelines of Appendix-S, ASME B31.3-2004. CAESAR output included the following in-line with the requirements of Appendix-S, B31.3:

5.4.1 Operating Load Case: The operating load case is used to determine the operating Position of the piping and reaction loads for any attached equipment, anchors, supports, guides, or stops. Hence, nodal movements and restraint loads are included in CAESAR output for operating load cases (W + P1 +T1 & W + P2 + T2).

5.4.2 Sustained Load Case: Sustained stresses due to the axial force, internal pressure, and

intensified bending moment are combined to determine the sustained longitudinal stress, SL. So, Nodal Stresses for sustained load case (W + P1 & W + P2) are included in CAESAR output and are compared with Allowable Code Stress.

5.4.3 Displacement Stress Range Load Case : The displacement stress range, SE, is based on the temperature range from the installation to maximum metal temperature for the thermal cycles under analysis. Hence, CAESAR output includes Displacement Stress Range for Expansion load case (L1 – L3 & L2 – L4) and is compared with the Allowable Stress range, SA, where SA is calculated automatically according to the following relationship defined in para. 302.3.5(d) of ASME B31.3-2004:SA = f (1.25Sc + 0.25Sh)




6.0 ALLOWABLE NOZZLE LOADS

Allowable Nozzle Forces and Moments from Thermal displacement and Deadweight are estimated from the following equations:

Axial force (Tension or compression) Fa = 2000 x B x D (N)

Tangential force (in plane of flange) FO = 1500 x B x D (N)

Longitudinal force (in plane of flange) FL = 2000 x B x D (N)

Torsional Moment MT = 150 x B x D2 (Nm)

Circumferential Bending moment MO = 100 x B x D2 (Nm)

Longitudinal Bending moment ML = 130 x B x D2 (Nm)

D = Nominal Dia. of Nozzle in inchesB = Factor dependent upon Nozzle Flange rating = 0.6 ( for Class 150#)

Hence, for 36”, 24” and 12” Nozzle, the Allowable loads are as under:

D B Fa Fo FL MT Mo ML

(Inch) (N) (N) (N) (N.m) (N.m) (N.m)

36 0.6 43200 32400 43200 116640 77760 10108824 0.6 28800 21600 28800 51840 34560 44928

12 0.6 14400 10800 14400 12960 8640 11232




7.0 CONSIDERATIONS & ASSUMPTIONS

7.1 Vessels are refractory lines; so, vessel expansion is neglected in comparison to Duct. Hence, no displacement is considered for the vessel Nozzles.

7.2 *Gimbal type Expansion Joints allow only the Angular movement. Hence, very large value was considered for the Axial and Lateral stiffness for these Expansion Joints during the CAESAR input. As per the classical approach in CAESAR, Gimbal type Expansion Joints are modeled with zero length.

7.3 As the flowing Fluid is Flue Gas, so, Fluid density is negligible and considered as zero during the CAESAR input

7.4 Coefficient of Frictions at Guides is taken as 0.3.

7.5 Valves has been modeled as Rigid Elements in CAESAR

7.6 Wind & Seismic Loads not considered during Analysis.

7.7 Flanged Joints not analysed.

7.8 Dynamic Analysis – Not applicable

7.9 Hydrotest load case – Not Applicable

* Refer Page 5.22 in Version 5.10 CAESAR II Applications Guide; 1985-2008 COADE, Inc.




8.0 RESULTS & DISCUSSION

The Results obtained from CAESAR are as follows:

8.1 Load on NozzlesFrom the Restraints summary report obtained from CAESAR-II it is clear that Loads on the following Nozzles are within permissible limits (as estimated in section-6 of this report):Node-10 : Nozzle N1 of R-9205Node-210: Nozzle N2 of FT-9204Node-1300: Nozzle N9 of R-9205Node-1380: Nozzle N10 of R-9205

8.2 Load on SupportsFrom the Restraints summary report obtained from CAESAR-II it is observed that Load on any of the supports is less than 5 Metric ton.

8.3 Rotation at Gimbal type Expansion JointAs evident from the above Nodal movements table obtained from CAESER-II, Rotation at any of the Gimbal type Expansion Joints is less than 10 Deg.

8.4 Nodal Stresses & Code complianceThe Nodal Stresses are listed in CAESAR output (Appendix A2). The nodal stresses are found to be less than Allowable Stress.

9.0 RECOMMENDATIONS

1. Before designing the Supports, Support Designer need to check the Nodal movements at Supports (listed in the CAESAR output). Support need to be designed to allow the Nodal movements at the corresponding support.

2. Supports to be designed according to the Support load tabulated in Restraint load table obtained from CAESAR-II analysis.




Appendices

A1 Stress Isometric

A2 CAESAR II Model

A3 CAESAR II Report

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