Training manual for PVelite (Basic Level).docx

Guidance with Patience To

Learn with Passion

PVELITE TRAINING – PRESSURE VESSEL DESIGN

Practice and make perfect

High structure integrity, safety and cost optimized static equipment

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PVElite Training – Basic

Table of Content Item

Description

Page

1.

Chapter 1: Static equipment, piping and storage tank. Relevant Code and Standards. Design Software

2- 3

2.

Chapter 2: Pressure Vessel Design , 2.1 Design by Rules or Formula, 2.2 Design by Analysis

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3.

Chapter 3: Types of loadings at Pressure Vessel

4.

Chapter 4: Type of Stresses at Pressure Vessel

5.

Chapter 5: Basic feature and Operation of PVElite

6.

Chapter 6: Common Design Code for Pressure Vessel

7.

Tutorial 1: Vertical Pressure

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8-11 12-20 21-28 29-31

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Chapter 1 : Types of Equipment and Facilities, Design codes and Application software

Chimney

Horizontal pressure vessel

Vertical pressure vessel Piping

Process column

Air fin cooler

Spherical storage tank

Shell & Tube Heat

Above round storage tank

Figure 1: Group of equipment and facilities at oil refinery plant A process plant ( Oil & Gas refinery, petrochemical, chemical and others) shall consists of following equipment and facilities. 2

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Pressur e Vessel

Storag e Tank

Code & Standard

Equipment or facilities detail

Recomm ended defector softwar e

ASME Sec VIII Div 1 or Div 2, PD5500, EN13445



PVElite ®, Nozzle Pro, FEpipe

API 650, API 620 ,API630



 

  

Heat Exchan ger

Piping

TEMA, PD5500,ASM E UHX, ASME Appendix A

    

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  

Process Vessels – Trayed columns, reactors, packed columns Drums and Miscellaneous Vessels – Horizontal and vertical vessels Storage Vessels – Bullet and spheres tanks

Cone roof tank ( Self supported and Supported) Dome roof tank Flat roof tank Floating roof tank (not in software yet)

Shell and Tube heat exchanger (Various configuration ) Hairpin Heat Exchanger Jacketed Pipe Heat Exchanger

ASME B31.1 ( Power piping) ASME B31.3 (Process piping) ASME B31.4 (Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids) ASME B31.5 ( Refrigeration Piping and Heat Transfer Components) ASME B31.8 (Gas Transmission and Distribution Piping Systems)

TANK®

Mech PVElite ® Thermal & flowHTRI®Xist, Xhep and etc CAESAR II®

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PVElite Training – Basic

Chapter 2 : Pressure Vessel Design There are two types of mechanical design methods for pressure vessel , namely design by formula (DBF) and design by analysis (DBA).

2.1

Design by Rule or Formula (DBF)

Design formula is governed by mandatory national code and standards to ensure safety performance. Most the pressure vessels are designed based on the concept of Design by Formulae (DBF), which involves relatively simple calculations to achieve the required component thicknesses via simple formulae or diagrams and by usage of the concept of the nominal design stress, also termed as allowable stress, allowable working stress, or limiting stress intensity; pressure vessel design codes like ASME Div VIII Section 1 and Section 2, PD 5500 and EN 13445 use the principle of thin wall structure membrane stress for determining the minimum thickness of structure such as cylindrical shell , conical shell, body flange and dish head thickness due to various loading conditions. The great benefit of the DBF approach is still its simplicity, only in the recent past the formulae and calculations in DBF have become more and more elaborate, pretending accuracy that is often not there (Josef L. Zeman, 2004). The basic idea of design by rule is that once the leading scantlings are fixed in this way the designer simply obeys the rules laid down in the procedures for specified components such as nozzles, dish head, shells, etc. The methodology or reasoning behind the rules will not always be apparent as we shall see. However, this is the most common approach used in all national design codes. The design by rule approach has the great advantage of simplicity and being backed up by the long experience of users in many cases. The greatest disadvantage is that the approach cannot easily be extended either to different geometries or additional loadings beyond the normal pressure cases, elastic –plastic and plastic state. For example, ASME VIII Div 1, the design rules and formulas consider mainly the loadings due to static internal pressure and external pressure within elastic limit.

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2.1.1 Design by Rule or Formula (DBF) using PV Elite Conventionally, most of the previous design of pressure vessel is done using spreadsheet like Microsoft Excel to perform structural thickness calculation and analysis for pressure vessel components. Nevertheless, this option can save some initial cost compare to commercial design software like PVElite, but it will be comparatively non cost effectiveness in the long run. This is obvious, when we compare PVElite to Microsoft Excel formatted design spreadsheet in term of the quantity and quality of the performance. Some of the points below are elaborate for getting better understanding about the advantages of using PVElite in pressure vessel design.  PVElite is “ user friendly” for both new and experienced user, where the input menu is ready available in a systematic arrangement ( if spreadsheet is used, you might enter the information to the wrong cell at spreadsheet that will cause a wrong output or even damage the whole program due to your carelessness ). User just enter the information as stated in the design datasheet and specification. Furthermore, if the user are doubt about the input , just press function key f1 to get technical advice from the help menu with useful statement, diagram , graph and table relevant to design requirement or national standard code ( if spreadsheet is used, you have to refer to the hard copy of design codes which will spent time in searching for the details .)  PVElite is “design oriented”, where the features allow the user to maximize their time to design or re-rating the pressure vessel to achieve cost- optimum design. That mean, minimize the time spent in searching, confirming and entering the design parameters for design calculation. To achieve this, PVElite performs calculation base on various type of design codes and corresponding material code with various addendum (ASME Sec VIII Div 1, Div 2 , PD5500 and EN13445), hence designer will be able to change and compare the pressure vessel design base on different standards easily . In addition, user can select various national codes for external loadings due to wind and/or seismic forces (ASCE, UBC, NCB ,IS , GB and etc.), nozzle loadings (WRC 5

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107 , PD5500 Annex B and etc), and tubesheet design (TEMA, ASME UHX, BS5500, ASME appendix A) Secondly, PVElite provides a good traceability for the calculation results where a negative answer is alerted in “red warning “, that the designer has the possibility to understand which are parameters to be changed in order to get the checking. While, a positive answer shows the result the degree of possible overdesign, in order to give the designer the possibly of decreasing excess thickness when they are not needed.  PVElite interfaces with others popular software packages for finite element analysis (Nozzle-Pro), heat exchanger design (HTRI), pressure vessel drafting and material take off (PV fabricator) and foundation design and drafting. PVElite also shares a bi-directional link to COADE’s CADWorx Equipment module. The significant benefit of this feature is the designer will be able to convert the preliminary design into drawings and MTO for cost estimation and proposal purposes using PV fabricator. In addition, the changes made in the PVElite in pressure vessel design will update the engineering drawing and bill of material correspondently. The mathematical model of the pressure vessel in the graphic form can be exported to Nozzle-Pro for meshing and generating finite element model for stress analysis such as nozzle to shell intersection, dome to shell intersection, skirt to shell and etc. After the heat and fluid flow analysis of heat exchanger using HTRI software, some relevant information can be transfer to PVElite for stress analysis for tubesheet, tube, tube to tubesheet joint and other components. The nozzle loading from CAESAR II can be transfer to PVElite for WRC 107 or annex B local stress analysis.  CodeCalc is an additional programs available within PVElite to analysis the vessel components separately or things that haven’t be included in PVElite . Typical cases would be fulljacketed vessel, non-circular vessel, Lifting lugs and turnion design, API579 (Fitness For Service), large opening at shell, floating head and etc.

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2.2 Design by Analysis (DBA) Design by analysis (DBA) is mainly used to check the design of pressure vessel which is operated under serve conditions like extreme high pressure, and extreme high or low temperature where DBF can not be used due to it limitations in design calculation, data and coverage (Design by Analysis, 2004). The design by analysis can be categorized into two: design base on elastic analysis, and design base on plastic analysis. It is implemented to avoid eight possible failure modes at pressure vessel by detail stress analysis as stated as in ASME sec VIII Division 2 and subsequently BS 5500 Appendix A and EN13445-3 Annex B (Direct Route Method) and EN13445-3 Annex C (Elastic analysis & stress Categorization). The failure modes considered are (base on ASME section VIII Div 2, Part 5) : All pressure vessels within the scope of this Division, irrespective of size or pressure, shall be provided with protection against overpressure in accordance with the requirements of this Part.  Protection Against Plastic Collapse – these requirements apply to all components where the thickness and configuration of the component is established using design-by-analysis rules.  Protection Against Local Failure – these requirements apply to all components where the thickness and configuration of the component is established using design-by-analysis rules. It is not necessary to evaluate the local strain limit criterion if the component design is in accordance with Part 4 (i.e. component wall thickness and weld detail per paragraph 4.2).  Protection Against Collapse From Buckling – these requirements apply to all components where the thickness and configuration of the component is established using design-by-analysis rules and the applied loads result in a compressive stress field. 7

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 Protection Against Failure From Cyclic Loading – these requirements apply to all components where the thickness and configuration of the component is established using design-by-analysis rules and the applied loads are cyclic. In addition, these requirements can also be used to qualify a component for cyclic loading where the thickness and size of the component are established using the designby-rule Requirements. Part 4. PVElite can only dealt with requirements that are directly addressed by the code and for cases where limitations prevent you from obtaining the necessary result, a viable alternative would be to turn to FEA (finite element analysis). PVElite does have interfaces with an FEA program termed Nozzle-Pro and this is beyond the scope of his manual.

3.0

Type of loadings at Pressure Vessel

All structure include pressure vessel are subjected to two basic types of loading: Steady or static and unsteady (variable, cyclic or impact). Figure 3.1 shows loadings which are grouped into steady and unsteady loads. Most of the pressure vessels encounter variable or cyclic loading, may assumed to be statically load without introducing serious error. This is significantly stated in the standard ( ASME Section VIII, Division 2, AD-160) that the fatigue analysis is required provided the conditions of the cyclic loading are exceed the limits at the fatigue evaluation stage. These limits is depend upon the number of cycle loads in term of fluctuate operating pressure and temperature, as well as the degree of the cyclic load which is mainly due to the gap of maximum and minimum operating pressure or temperature. Figure 3.2 shows types of general loads and local loads at pressure vessel. Internal pressure load is common for all the pressure vessel above, since all the static equipment operates at certain elevated pressure and temperature due to chemical processes and hydrostatic pressure of storage content ( ASME Section VIII, Division 1, Part UG20 and UG21, 2007). In addition, hydrotest pressure load is elevated at 30% from the vessel working pressure at corroded or new condition as stated in ASME Division 1, Part UG99. 8

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PVElite Training – Basic Despite the availability of vacuum valve, the external pressure is considered for pressure vessel design in vacuum condition where the outlet nozzle is connected to pump. The atmosphere pressure is sufficient to compressively deform a pressure vessel due to large volume vessel with insufficient thickness and/or stiffener, furthermore metallic materials have relatively low compressive strength compare to its tensile strength (ASME Section VIII Division 1, Part UG28, 2007). External load like wind and seismic load is more critical for process vessels like process columns and reactor. The deflection and vibration analysis of tall slender column (H/D>15) are commonly checked to ensure Types of loading

the structural is not over deflected. In conjunction, the stresses induced by wind and seismic loads are always combined with other stresses (i.e. longitudinal, circumferential and shear stress) due to internal pressure, external pressure, and hydro test pressure to ensure the possible combined

Steady load – long-term duration, continuous Non steady loads—short term duration, variable

stresses are not more than allowable stress (ASME Section VIII Division 1, Part UG22-23, 2007).

Pressure loads – Internal or external pressure (design, operating, and hydrostatic head of liquid) Shop and field hydrotest

Dynamic/ impact load

Dead weight, vessel content

Lifting and erection

Loadings due to attached piping and equipment. Start up, shut down .

Loadings to and from vessel support

Transportation

Thermal load – Head to skirt joint, piping Thermal expansion load at nozzle. load – short term during service or testing

Wind load

Earthquake, Vibration

9 Upset, emergency Constant cyclic pressure or thermal load

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Categories of loading at pressure vessel

eneral loads – Load applied continuously across a vessel section. Local loads – Load applied to a small portion .of the vessel and normally fall off rapidly in d

Figure 3.1: Types of Loading at pressure vessel

s- Internal or external pressure load (design, operating, hydrotest, andand hydrostatic or liquid.) Pressure radial loadsInternal external head pressure for thick wall pressure vessel.

Shear loads- Longitudinal and circumferential shear at shell, dish head and conical section, where saddle and support oads- Bending moment due to wind, seismic, erection, transportation and horizontal support.

nsile loads- Due to dead weight, installedTorsional equipment, ladders, platforms, piping,nozzle and vessel content. loadstorsional load at vessel due to the twist of external piping.

load due to moment at discontinuities, nozzle to shell section. Thermal loads- Skirt Moment to head loadsattachment.

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Thermal loads- Thermal expansion restricted regions likes piping at nozzle connection

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PVElite Training – Basic

Figure 3.2: Categories of Loading at pressure vessel

In addition to the above major analysis, nozzle opening reinforcement at shell is important to avoid mechanical failure due to internal pressure, external pressure and nozzle loading due to external piping connection and other equipment likes reboiler due to various forces and moment at nozzle to shell junctures (K.R.Wichman., A.G. Hoper., J.L.Mersho, 1979). This concept is applicable to other attachments at the pressure vessel walls which have rectangular, square or circular cross sectional area. For horizontal supported pressure vessel, the distributed weight implement bending load

at the mid span of the pressure vessel and the

saddle support. Furthermore, the concentrated load at the horn of saddle and the tip of the wear plate. The above loads are significant for large diameter and long horizontal pressure vessel. ( L.P. Zick, 1951) Local stresses analysis is important for lifting lugs and turnion to ensure safe lift during the site installation. Fatigue analysis is performed for those pressure vessels which have severe and significant cyclic loadings in the form of fluctuating pressure and temperature condition. These cyclic loads would decrease the service life of a pressure vessel as stated in the S-N curve of specific material. ( ASME 11

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PVElite Training – Basic Section VIII, Division 2, Appendix 5) Thermal loads is only concerned for DBF likes ASME Division for tube sheet design. ASME Division 2, part 5 – Design By Analysis Requirements (2007) checks the stresses induced by cyclic thermal loads, and the ratcheting for pressure vessel components.

4

Type of stresses at Pressure Vessel

Generally the design of pressure vessel is to decide the minimum thickness which will fulfill the design requirement as per design code through DBF or DBA. The pressure vessel components thickness are depend upon the stress(es) incurred at the material due to internal pressure, external pressure and other external forces. It is not necessary to find every stress but rather to know the governing stresses and how they related to the pressure vessel and its respective parts, attachments, and supports. Hence, the basic understand of the stresses at pressure vessel is importance for design and they are further elaborated as below. Generally, there are three types of stresses:-

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- General Primary Stress - Secondary Stress - Peak Stress

4.1 General Primary Stress These stresses act over a full cross section of the vessel and they are produced by the imposed loading (load-induced) and are necessary to satisfy the law of equilibrium. In addition, they are the most hazardous of all types of stress. The basic characteristic of primary stresses that it is not self limiting (i.e. they are not reduced magnitude by the deformation they produced). Hence, the gross distortion or failure of the structure will occur if its value substantially exceeds the yield stress . In the other word, if a primary stress exceeds the yield strength of the material through entire thickness, the prevention of failure is entirely dependent on the strain- hardening properties of the material or stress distribution. Primary stress are generally due to internal or external pressure or produced by sustained external forces and moment. The primary stress is divided into two subcategories in ASME Sec VIIDiv 2. They are primary general membrane and primary general bending stresses. Primary general membrane stress ,P m. This stress occurs across the entire cross section of the vessel. It is remote from discontinuities such as head-shell intersections, cone-cylinder- intersections, nozzles, and supports. For instance, circumferential and longitudinal stress due to pressure; compressive and tensile axial stresses due to wind or seismic; longitudinal stress due to the bending of the horizontal vessel over the saddles; membrane stress in the center of the flat head; membrane stress in the nozzle wall within the area of reinforcement due to pressure or external loads and axial compression due to the weight.

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Figure 3.3: General membrane stress at the pressure vessel parts

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PVElite Training – Basic Primary general bending stress, Pb. Primary bending stresses are due to sustained loads and are capable of causing collapse of the vessel. There are relatively few areas where primary bending occurs. For instance, bending stress in the center of the flat head or crown of a dished head; bending stress in a shallow conical head and bending stress in the ligaments of closely spaced openings.

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Local primary membrane stress, PL. Local It is a combination of two stresses, primary membrane stress, Pm, plus secondary membrane stress, Q m which is produced from sustained loads. These have been grouped together in order to limit the allowable stress for this particular combination to a level lower than allowed for other primary and secondary stress application. It was felt that local stress from sustained not self limiting loads presented a great enough hazard for the combination to be classified as a primary stress. Examples of primary local membrane stresses are primary membrane stress plus membrane stresses at local discontinuities (i.e. head to shell juncture and nozzle to shell juncture), primary stress plus membrane stresses from local sustained loads (i.e. platform and ladder support; piping and equipment attached to the nozzle).

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4.2 19

Secondary Stress

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PVElite Training – Basic Secondary stress is developed when the deformation of a component due to the applied loads is restrained by other components. It must satisfy an imposed strain pattern rather than being equilibrium with an external load. Secondary stress is self-limiting (i.e. they are reduced magnitude by the deformation they produced) in that local yielding can be redistribute the stress to a tolerable magnitude without causing failure. Secondary mean stresses are developed at the junctions of major components of a pressure vessel. Secondary mean stresses are also produced by sustained loads rather than internal or external pressure. Secondary stresses are strain-induced stresses. Secondary

stresses

are

divided

into

two

additional

groups,

membranes and bending. Examples of secondary membrane stress are axial stress at the juncture of the flange and the hub of the nozzle; thermal stresses due to restricted expansion; membrane stress in the knuckle area of the head and membrane stress due to local relenting (self-limiting) loads. Examples of secondary bending stress, Q b are bending stress at a gross structural discontinuity (i.e. nozzle and lugs); the non uniform portion of the stress distribution in a thick walled vessel due to internal pressure; the stress variation of the radial stress due to internal pressure in thick- walled vessels; discontinuity stresses at stiffening or support rings.

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4.3 Peak Stress Peak stress is the highest stress in the region under consideration. The basic characteristic of peak stress is that it causes no significant distortion and is objectionable mostly as sources of fatigue failure. It applies to both sustained load and self- limiting load. Peak stress is additive to primary and secondary stress present in the point of the stress concentration. Peak stress is only significant in fatigue conditions or brittle materials. It is the sources of fatigue cracks and applies to membrane, bending, and shear stress. Example are stress at the corner the discontinuity; thermal stresses in a wall caused by the sudden change in the surface temperature; thermal stresses in cladding or weld overlay; stress due to the notch effect .

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5 Basic features and operation of PV Elite Generally, there are five major input processors in PVElite. There are i) ii) iii) iv) v) vi)

Heading Design Constraint General Input Load Cases Seismic Data Wind Data

Figure 4.1: Input Processors for the Pressure Vessel design

Before the user start to enter the design parameters into the input processors as stated above , it is important to configure the settings at the start. The configuration is at the tools option control utility processor as shown in figure 2.2.

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5.1 Configuration

Figure 4.2 : Configure the settings of PVElite behaves when analyzing a vessel

It is important to configure the settings at the start. From the tools option control utility processor, options are given to customize how PVElite behaves when analyzing a vessel. The settings are related to the pre and post processing of the design or analysis for pressure vessel. Pre-processing is the settings of the design requirements before the analysis, likes alternative rules in design of pressure vessel components (i.e. use ASME Code case2260/2261, 2286, 2004-A06 Addenda for Division 2, pre-99 Addenda (Division 1 only) , Eigen solver and use OD as the basis for shell radius for Zick’s analysis) or the setting allowable value such as material database, graph for determining MDMT and allowable tower deflection. In addition, post –processing involves filter or keep certain results or details to be appear in the report such as no MDMT, no MAWP calculation, print equation and substitution. It is important for the user to be familiar to the design standards, practice and client required specification before perform any setting in the configuration section. 23

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5.2

Design/ Analysis Constraints

Figure 4.3: Design constraints for setting general design information for pressure vessel

5.3 24

Design Data

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PVElite Training – Basic The input screen is divided into two areas. They are design data and design modification. The design data section is related to general design parameter like internal and external pressure /temperature, hydrotest type and position, projection from to/ bottom for UG99-C . This information is very common seen and indicated in the design data of vessel GA drawing and this core information for pressure vessel design. The user can specific their client preferred MAWP, MAPnc and hydrotest pressure, where these values will overwrite/ replace the calculated values. Others inputs like construction type, special service, degree of radiography are just for information only, it is reported in the report echo. If the user check the box of “Use Higher Longitudinal Stresses ?”, PVElite will use higher allowable longitudinal stress for combined stresses analysis . The ASME Code Section VIII, Division 1, Paragraph UG-23(d) allow the allowable stress for the combination of earthquake loading, or wind loading with other loadings to be increased by a factor of 1.2. If the user check the box of “Consider Vortex Shedding ?”, PVElite will compute fatigue stresses based on loads generated by wind flutter. In addition, the program will compute the number of hours of safe operation remaining under the wind vibration conditions. This section is suitable for high column design with h/d (overall high over the vessel diameter) equal or more than 15. For low vertical vessel like drum, it is advisable not to check the box because the program will generate extreme non logical high value which will cause overdesign for the structure. If the user check the box of ”Is This a Heat Exchanger ?”, PVElite will write out an ASCII text file that contains the geometry and loading information for this particular vessel design. If user check the box of “Hydrotest allowable is 90% yield”, PVElite will consider 90% of the material yield stress for the hydrostatic test allowable. This will generate higher allowable stress for hydrotest than the normal value which is 1.3 time the material minimum allowable stress. ( This applies only for Division 1 vessel design). If user is designing a cylindrical ASME stack steel stack and wish to have PVElite analyze allowable and stress combinations per ASME STS-2003(a), then check this box. (This applies for Division 1 vessel design). The 2009 version do not allow any modification of design code in this input screen, but it is shown at the column for information. The reason of this new feature is to remind the designer to select the design code at the earlier stage (Refer to figure 2.4).

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PVElite Training – Basic

Figure 4.4: Selection of design code at “New” column and pull down menu

Any modification at design data will affect design of the whole pressure vessel and it components. For example, the change of internal design pressure and temperature at this section will generate global change for all the components of the pressure vessel at general input processor. In addition, the change of design code for whole vessel is done by reselecting the required design code at pull down menu. However, the user needs to reselect the material before running the analysis.

5.4

Design Modification

Design modification provides the user with the option to intelligently design the vessel whenever a specific section fails the code. The program will prompt a thickness that will be suitable for use or a location (s) of stiffening rings so that the code requirement can be met. For the stiffening rings, the program will allocation the ring(s) after run the analysis, where the program will ask for user permission before the changes take place. (Note: For most Advance users, the options included are usually not used.)

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5.5

Load Cases

Figure 4.5: Load cases for stress combination at pressure vessel

5.5.1

Stress Combination Load Cases

This input processor is used to deal with various combinations of loads that contribute toward the membrane stress of the vessel at longitudinal direction. The calculated maximum principle stresses based on different combination of loads will be compared with the corresponding allowable stress.

There can be as many as twenty cases, combining pressure loads, weight loads, and moments in various ways. Generally, the load cases stated are more than adequate to deal with all the combinations that the user are likely to encounter in both operational and hydrotesting conditions. 27

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A fairly complete set of load cases is included as a default:

The difference between wind loads and hydrotest wind loads is simply a ratio (percentage) defined by the user. This percentage is specified in the Wind Data definition of Global Data - usually about 33% (thus setting the hydrotest wind load at 33% of the operating wind load). Likewise, the hydrotest earthquake load is a percentage of the earthquake load; this percentage is defined in the Seismic Data definition of Global Data. Some steps that are not applicable for horizontal vessels, such as natural frequency, will not be printed. Also, if a vessel has no supports, then there will be no calculations that involve wind or seismic loads.

5.5.2

Nozzle Design Options

The nozzle design option dealt with the design criteria that determine the selection of nozzle wall thickness and reinforcement pad. The top 28

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deals with design pressure that is used to calculate the thickness (nozzle or clip) base on MAWP+ Static head to Bottom Element, Design Pressure + Static head, Overall MAWP + Static head (governing Element), MAWP + Static head to Nozzle (note: user must select either one for their vessel’s nozzle design). The least of the boxes is optional for vessel design. If the user checks the box of ”Consider MAPnc in Analysis “, PVElite will check to see if the nozzle is reinforced adequately using MAPnc generated during the internal pressure calculation. When the area of replacement calculations are made for this case, cold allowable stresses are used and the corrosion allowance is set to 0. Designing nozzles for this case helps the vessel to comply with UG99 or appropriate (hydrotest) requirements. If the user check the box of “Modify Tr based on the Maximum Stress Ratio”, PVElite will looks at all of the defined load cases (combined stresses) and select the highest stress ratio (actual stress/ allowable stress). It will then use this number as a multiplier on the shell thickness. Thus the nozzle design is based on the precise loading at the bottom of that shell course. The reason for the above work is to comply with ASME Section VIII Division 1 paragraph UG-22 that deals with supplemental loadings. One factor in ASME nozzle design is the required thickness of the shell (tr). Usually internal pressure (hoop stress) governs. In some cases, such as when a nozzle is located on a shell course at the bottom of a tall tower, longitudinal stresses will govern. In this case the shell required thickness must be based on longitudinal stresses and not the hoop stress.

6 Common design Code for Pressure Vessel 29

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ASME Section VIII Div 1, Ed 2007, Ad 09 ASME Div 1 is the most common use standard for pressure vessel design, the following are some of the common consideration in pressure vessel design.

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Tutorial (1) : 32

Design for vertical pressure vessel

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Tasks to be complete :       



To determine the structural thicknesses of cylindrical shell and semi ellipse head due to internal and hydrostatic pressure conditions. Check shell thickness against hydrotest pressure. MDMT checking for all pressure vessel components. To determine the allowable external pressure of the structure and compare to the actual external pressure load due to vacuum condition at pressure vessel. Design skirt support and base ring design for vertical pressure vessel due to wind and seismic load. (refer to PVElite database or handbook data if possible). Nozzle reinforcement at dome shell due to shell opening, Nozzle minimum thickness. Installation of internals – trays and packing, platform and ladder, longitudinal. After that determine the combined stresses condition at bottom structure. Do the necessary correction, if there is a need. Perform rigging analysis to check the shear stress and bending stress of the vertical vessel during critical lifting position.

Learning Outcome: After completion of this topic, student will be able to use PVelite for :  Input all the design parameters to the correct input cursor.  Run the analysis and correct the design error by adjusting the design parameter accordingly.  Obtaining an cost optimize design for pressure vessel components due to internal pressure, external pressure, nozzle reinforcement , external loadings and skirt support. (target :+-10% greater than actual load/stress/deflection rate) (Note: Indicate the results with yellow highlight for printed copy and save a PVE. file in CD for further evaluation)

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PVElite Training – Basic Tutorial (1) : Vertical pressure vessel Design Parameter 1) Vessel name / number 2) Design Code & Addenda 3) Operating Pressure & Temperature 4) Vessel Design Pressure & Temperature 5) Minimum Metal design Temperature

Variable Distillation column / WRG-100 ASME Section VIII Division 1, Addendum 2007 10 bar (internal), 300oC / -1 bar (vacuum), 300oC 15 bar (internal), 300oC/ -1 bar (vacuum), 300oC MDMT = -25oC

6) Vessel dimension ( Inside Diameter (ID) x Length tangent to tangent (L)) Conical sectional height (L) 7) Design Liquid Level / content specific gravity 8) MAWP / MAP(N &C)

3500 mm (diameter) x 30,000 mm (L) 2500 mm (diameter ) x 10,000 mm (L) 1500 mm (L)

9) Hydrotest pressure (shop/field)

UG99(b), Shop ( ) 2 N/mm ( Applicable/ Not Applicable0 Dome end : meridoinal seam (Full RT) circumferential seam ( spot RT) Cylindrical shell : meridoinal seam (spot RT) circumferential seam ( spot RT) 3 mm for all parts

10) 11)

Heat treatment Joint Efficiency

11) Corrosion Allowance 12) Material - Cylindrical shell - Dome end - Nozzle - Nozzle flange - Bolting - Skirt 13) Weights

3500 mm from bottom TL / 0.85 (

SA 516 GR70 SA 516 GR70 SA 106 GR B SA 105 SA193/ SA194 SA283 GRC Fabrication : ( Empty: ( Operating: ( Test:

14) Wind load

15) Seismic load

34

) N/mm2

) tones ) tones ) tones (

) tones

Wind Design Code: ASCE-93 Wind for Hydrotest: 33% Design Wind Speed: 120 km/hr Base Elevation : 3 meters from sea level Important factor: 1, Roughness factor: 1 Seismic Design Code: ASCE-93 Seismic for Hydrotest: 0%

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PVElite Training – Basic Seismic Coefficient Av: 0.2 Seismic Coefficient Cc: 2 Performance Factor: 1

N1

2:1 Semielliptical Head, SF=50mm, min thk ( ) mm, Nominal thk ( )mm.

(Indicate the shell thickness of the shell section)

2,500 mm

10,000m m

1,500mm

Tray – space =400mm, QTY = 10 trays , Holding height = 50 mm 4500 mm from 6th Platform 0o to 180o

Cage ladder , appx – 10kg/m

4500 mm from 5th Platform 180o to o 0

ID =3,500 mm

4500 mm from 4th Platform 0o to 180o

30,000m m

rd

4500 mm from 3 Platform 180o to 0o

CS ratchet ring – 45lb/ft3 Volume = 43.3 m3

4500 mm from 2nd Platform 0o to 180o st

4500 mm from 1 Platform 180o to 0o M1

5500 mm from ground oo to 180o 2:1 Semielliptical Head, SF=50mm, min thk ( ) mm, Nominal thk ( )mm.

35

Platform – used open lattice (lightest option). PL width = 1000 mm PL Height = 1200 mm Clearance = 4”

Packing support Height =50mm , weight =585 kg Elevation =6000 mm from lower TL.. percentage of holding liquid =65%

5,000mm N2

36

PVElite Training – Basic

Nozzle Detail No 1.

Nozzle Description Inlet ( N1)

3.

Outlet (N2)

4.

Manhole (M1)

36

Dia x Sch X L 18” x sch 40 x 200L 20” x sch 10 x 250L 24” x 12thk x 300L

Pound rating (#) ANSI, WNRF ,300# ANSI, WNRF,f150 # ANSI, WNRF 150#

Orientati on 600 from CL (120o) CL 0o

Elevation from lower SF Top dish head Bottom dish head 5000 mm

1

37

PVElite Training – Basic

Tutorial (2): Design for horizontal pressure vessel Tasks to be complete :



Internal pressure, hydrotest , external pressure calculation as practical 1. Nozzle opening and reinforcement , Nozzle loading WRC 107 checking. Longitudinal stresses at horizontal supported pressure vessel at the mid span and saddle support during the operation and hydrotest respectively. Tangential stress at the shell at saddle support, Circumferential compression at bottom of shell and in plane of saddle and circumferential bending at horn of saddle. Corrective methods in reducing the stress at horn of saddle – add wear plate, increase the contact angle and support width, move saddle toward the head, add stiffer ring at the saddle, add the saddle support(s). Design for the saddle support, base plate, rib plate, wed plate.

Learning Outcome: After completion of this topic, student will be able to use PVelite for : Input all the design parameters to the correct input cursor. Run the analysis and correct the design error by adjusting the design parameter accordingly.  Obtaining an cost optimize design for pressure vessel components due to internal pressure, external pressure, horizontal supported conditions, nozzle reinforcement , nozzle loading, external loadings and saddle support. (target :+-10% greater than actual load/stress/deflection rate) (Note: Indicate the results with yellow highlight for printed copy and save a PVE. file in CD for further evaluation)  

1) Vessel name / number 2) Design Code & Addenda 3) Operating Pressure & Temperature 4) Vessel Design Pressure & Temperature 5) Minimum Metal design Temperature 6) Vessel dimension ( Inside Diameter (ID) x Length tangent to tangent (L)) 7) Design Liquid Level / content specific gravity 37

Slug Catcher ASME Section VIII Division 1, latest Addendum 3.5 bar (internal), 120oC / 1 bar (external),60oC 5.5 bar (internal), 120oC/ 1 bar (external), 60oC MDMT = -35oC 4200 mm (diameter) x 18,000 mm (L) 3800 mm from bottom / 1

38

11) Corrosion Allowance

PVElite Training – Basic ( ) N/mm 2 UG99(c), Shop ( ) 2 N/mm ( Applicable/ Not Applicable0 Dome end : meridoinal seam (Full RT) circumferential seam ( spot RT) Cylindrical shell : meridoinal seam (spot RT) circumferential seam ( spot RT) 0

12) Material - Cylindrical shell - Dome end - Nozzle - Nozzle flange - Bolting - Saddle

SA 240 SS304 SA 240 SS304 SA 312 TP304 SA 182 F304 SA320 B8 with SA-194 B SA283 GRC

8) MAWP / MAP(N &C) 9) Hydrotest pressure (shop/filed) 10) 11)

Heat treatment Joint Efficiency

13) Weights

Fabrication : ( Empty: ( Operating: ( Test:

14) Wind load

) tones ) tones ) tones

(

) tones

Wind Design Code: ASCE-93 Wind for Hydrotest: 33% Design Wind Speed: 120 km/hr Base Elevation : 3 meters from sea level Important factor: 1, Roughness factor: 1 Seismic Design Code: ASCE-93 Seismic for Hydrotest: 0%

15) Seismic load

Seismic Coefficient Av: 0.2 Seismic Coefficient Cc: 2 Performance Factor: 1 Tutorial (2) : Horizontal pressure vessel

Nozzle Detail No 1.

Nozzle Description Inlet ( N1)

3.

Drain pipe (N2)

4.

Boot (B1) 38

Dia x Sch X L 20” x sch 10 x 200L 3” x sch 10 x 250L 30” x 12thk x

Pound rating (#) ANSI, WNRF ,150# ANSI, WNRF,150# ANSI,

Orientati on 0O

distance from left SF 4500 mm

CL

Boot dish head

0o

12,000 mm

39

PVElite Training – Basic 3000L

WNRF 150#

N1

18,000

4,200

3600 mm

500 mm B1

User estimated the size, thickness of the saddle and its components. The distance from saddle centre line to

12,000 2:1 Semielliptical Head, SF=50mm, min thk ( ) mm, Nominal thk ( )mm.

N2

(Indicate the shell thickness of the shell section) Nozzle Loading (WRC 107) Dead Weight No

Nozzle Description 1. Inlet ( N1) 3. Drain pipe (N2) 4. Boot (B1) Thermal

P (N)

No

P (N)

800 300 NA

1.

Nozzle Description Inlet ( N1)

3.

Drain pipe (N2)

750

4.

Boot (B1)

NA

1,800

VL (N) 1200 500 NA

Vc (N)

Mt(N/m)

ML(N/m)

Mc(N/m)

1200 500 NA

120 50 NA

150 60 NA

150 60 NA

VL (N) 2,40 0 1,00 0 NA

Vc (N)

Mt(N/m)

ML(N/m)

Mc(N/m)

2,400

2,600

3,000

3,000

1,000

1,115

1,300

1,300

NA

NA

NA

NA

Topic (3): Design of high wall thickness pressure vessel (t > 100 mm) Sub-topic: 

39

Dish head selection for high pressure operation.

40

PVElite Training – Basic 

Code case – 2260 “Alternative design rules for Ellipsoidal and Torispherical



formed heads. Saddle type nozzle/ insert plate for nozzle opening reinforcement, Support lugs design.

LOC:

After completion of this topic, student will be able to Input all the design parameters to the correct input cursor. Run the analysis and correct the design error by adjusting the design parameter accordingly. Obtaining a cost optimize design for pressure vessel components due to high pressure operation.

Contents 1.0 Design of high wall thickness pressure vessel (t > 100 mm) ( Division 1 , 2 and PD5500) 3.1 Dish head selection for high pressure operation - semi ellipse, torispherical, hemispherical formed head. 3.2 Nozzle design for thick wall pressure vessel. 3.2.1 Self- reinforcement nozzle design. 3.2.2 Saddle nozzle or insert plate design. 3.3 Change the previous design of ASME Div 1 to ASME Div 2 and PD 5500. Material nominal strength/ allowable stress calculation - PD 5500 Annex K. ASME Section VIII Div 1 and Div 2. 3.4 Support lugs design and local stress calculation (WRC 107).

1) Vessel name / number

Inlet Gas Separator

2) Design Code & Addenda

ASME Section VIII Division 1, Addendum 2007

40

41 3) Operating Pressure & Temperature

PVElite Training – Basic 125 bar (internal), 120oC / NA(external)

4) Vessel Design Pressure & Temperature 5) Minimum Metal design Temperature 6) Vessel dimension ( Inside Diameter (ID) x Length tangent to tangent (L)) 7) Design Liquid Level / content specific gravity

138 bar (internal), 120oC/ NA (external) MDMT = -15oC

8) MAWP / MAP(N &C) 9) Hydrotest pressure (shop/filed) 10) Heat treatment 11) Joint Efficiency

11) Corrosion Allowance

TBA TBA As per ASME code Dome end : meridoinal seam (Full RT) circumferential seam (Full RT) Cylindrical shell : meridoinal seam (Full RT) circumferential seam ( Full RT) 0

12) Material - Cylindrical shell - Dome end - Nozzle - Nozzle flange - Bolting - Support Lugs

SA 516 GR70N SA 516 GR 70N SA 105 SA 105 SA 193 SA283 GRC

13) Weights

2760 mm (diameter) x 7600 mm (L) 2000 mm from bottom / 0.85

Fabrication : Empty: Operating: Test:

14) Wind load

15) Seismic load

Tutorial (3): Heavy wall pressure vessel

41

tones tones tones tones

Wind Design Code: ASCE-93 Wind for Hydrotest: 33% Design Wind Speed: 120 km/hr Base Elevation : 3 meters from sea level Important factor: 1, Roughness factor: 1 Seismic Design Code: ASCE-93 Seismic for Hydrotest: 0% Seismic Coefficient Av: 0.15 Seismic Coefficient Cc: 2 Performance Factor: 1