Final report_2

Fabrication of Pressure Vessels 1

Internship Report on Fabrication of Pressure Vessels Submitted in partial fulfillment of the requirement for the award of the degree of Bachelor of Engineering in Mechanical Engineering by Bheem Roll No. 101808105 Submitted to Department of Mechanical Engineering Thapar Institute of Engineering and Technology Patiala – 147004 Under the supervision of Mr Rajesh Tamak (Manufacturing Plant Head) D-21, Bahadrabad Industrial Area, Haridwar, Uttarakhand 249402 2

CERTIFICATE 3

ACKNOWLEDGEMENT I am very thankful to , who has provided me with an amazing opportunity to gain knowledge at SUEZ, Haridwar. It was an incredible experience to do internship over here. I learnt many things; some practically, which I have learnt theoretically earlier. I also pay my gratitude to the Almighty for enabling me to complete this Internship Report within due course of time. For his continuous guidance, enthusiasm and support extended, I take this opportunity — with sheer pleasure — to express my heartfelt gratitude to Mr. Rajesh Tamak, Plant Head, Suez for allowing me to take training at their works. SUEZ for giving me all the possible help and necessary guidance during my training period. The acknowledgement remains incomplete without thanking the several factory personnel for their kind cooperation and a special mention, Mr. Vijender Kumar for enhancing my working knowledge about a company. Words are very few to express an enormous gratitude to my affectionate Parents for their prayers and strong determination, enabling me to achieve this internship. I am highly indebted to my supervisor for the training period, Mr. Kuldeep Singh (Manager-Manufacturing). Without his kind assistance and expertise my training would not have been possible. The experienced personnel he is, he has been a constant source of inspiration and encouragement and who has had solutions to all my problems, answers to all my questions and who has been full of insight and enthusiasm, right from my day one at training, until the completion of this report. Lastly, I appreciate the Mechanical Department of my University to have given me the opportunity to work and gain knowledge from the professional environment of SUEZ and hence broaden my vision. 4

ABSTRACT Within my educational program at the Thapar Institute of Engineering and Technology Patiala, I had had the opportunity to carry my internship at SUEZ, Haridwar and besides practical experience in the area of fabrication, many valuable skills and practical knowledge was gained during the internship duration. Throughout the internship drawing assignments were assigned to me by my supervisor such as the study and use of codes and standards for construction of pressure vessels, basic design calculations as per the codes and fabrication drawings on CAD. The course of action adopted to complete these activities was to first understand the assignment on hand, then understanding the purpose of the assignment and then learning how to do the required task in an efficient way. These activities were done according to the course of actions followed at SUEZ works. I spent a considerable amount of time on-field to observe the fabrication and inspection processes, manufacturing of pressure vessel heads (torispherical) by hydraulic press and spinning machine, rolling of plates by rolling press for pressure vessel shell, welding by TIG/MMAW/SAW and finishing by grinding, blasting and painting, And some of the Non-destructive. I mention certain details of the assignments given to me, at the end. Also, training in this company has increased my knowledge in the technical field. This would much more be beneficial, in view of future prospects. Keywords: Manufacturing, ASME BPVC, Vessel Fabrication, CAD, Field Study 5

LIST OF TABLES Table 1 - Surface Treatment Facilities Table 2 - Facilities for NON-Destructive Test Table 3 - PLATE BENDING COLD Table 4 - LIFTING CAPACITY Table 5 - CUTTING AND GRINDING EQUIPMENT Table 6 - WELDING MACHINES Table 7 - MACHINE SHOP Table 8 - WORK FORCE LIST OF FIGURES Fig 1: Types of pressure vessel Fig 2: TIG WELDING FIG 3: MIG Welding Fig 4: Fused flux Fig 5: SAW Fig 6 Stress Relieving Furnace Fig 7: Blasting area Fig 8: Painting Fig 9: Finishing Fig 10: DPT Fig 11: Radiography Area Fig 12: Radiography test Fig 13: Hardness test Fig 14: Hydro test Fig 15: Water fill test Fig16: Spark test Fig 17: Types of pressure vessel shell Fig 18: Torispherical head 6

Fig 19: Hemispherical head Fig 20: Conical head Fig 21: Flat head Fig 22 - Pressure Vessel Horizontal with Saddle Support Fig 23: Leg Support Fig 24: Lug Support Fig 25: Skirt Support Fig 26: pressure vessel shell FIG 27: PV elite Fig 29: Cracking FIG 28: Engineering Drawing FIG 30: Creep Strain-Time graph FIG 31: Stress corrosion cracking FIG 32: Ductile and brittle fractures FIG 33: Wear Failure FIG 34: Hydrogen Embitterment FIG 35: Welding joint 7

TABLE OF CONTENTS Page 4 Title 5 ACKNOWLEDGEMENT 6 ABSTRACT 6-7 LIST OF TABLES 10 LIST OF FIGURES 12 Chapter 1 INTRODUCTION 1.1 SUEZ GROUP 15 1.2 ABOUT ASME 16 1.3 The Codes and Standards 18 Chapter 2 SUEZ COMPANY PROFILE 2.1 SUEZ PRODUCTS 22 2.2 CLIENTELE 23 2.3 INSPECTION AND TESTING FACILITIES 25 2.4 FABRICATION FACILITIES 2.5 MACHINE SHOP 26 2.6 WORK FORCE 28 29 Chapter 3 PRESSURE VESSELS Chapter 4 STEP BY STEP FORMATION OF PRESSURE VESSEL 4.1 BRIEF STEPS FOR FABRICATION PROCESS 4.2 IN PLANT PROCESSES Chapter 5 WELDING 5.1 GAS TUNGSTEN ARC WELDING (GTAW, TIG) 5.2 MANUAL METAL ARC WELDING (MMAW) 5.3 SUBMERGED ARC WELDING (SAW) Chapter 6 STRESS RELIRVING FURNACE Chapter 7 DESIGN CODES AND STANDARDS Chapter 8 BLASTING/PAINTING 7.1 BLASTING 7.2 PAINTING Chapter 9 FINISHING/POLISHING Chapter 10 RUBBER CURING THROUGH VULCANIZER Chapter 11 NON-DESTRUCTIVE TESTS (NDTs) 8

11.1 PENETRANT TEST OR DIE PENETRANT TEST 11.2 RADIOGRAPHIC TEST 11.3 WELDING HARDNESS TEST 11.4 HYDRO TEST 11.5 WATER FILL TEST 11.6 SPARK TESTING Chapter 12 PRESSURE VESSEL HEADS (TORISPHERICAL) 37 Chapter 13 SUPPORT FOR PRESSURE VESSEL 39 13.1 SADDLE 13.2 LEG 13.3 LUG 13.4 SKIRT Chapter 14 PRESSURE VESSEL SHELL 42 Chapter 15 ASSIGNMENTS 43 15.1 Selection of material, IS 2062(Indian Standard Structural Steel) 15.2 Stress Analysis of Pressure Vessels 15.3 Pressure vessel Engineering Drawing/PV Elite Software Chapter 16 THEORIES OF FAILURE 54 16.1 FAILURE IN PRESSURE VESSELS 16.2 CAUSES OF FALIURE Chapter 17 CONCLUSION 59 Chapter 18 REFERENCES 60 9

Chapter 1: INTRODUCTION 1.1SUEZ GROUP From the inauguration of the Suez Canal through the revolutions of hygiene and public health, urban comfort, our solutions and technologies have accompanied cities and industries to meet the challenges of urban and demographic growth. 150 years after the inauguration of the Suez Canal, SUEZ builds on its pioneering history and culture of innovation to announce a new ambition: to shape a sustainable environment, now, with cities, industries and citizens. In order to accelerate its growth in the industrial water treatment market, SUEZ announces it has entered into an agreement to acquire the majority stake in Driplex, a well-established Indian company and a leading player in the industrial market. With over 350 employees, Driplex is specialized in engineering, design, manufacturing and commissioning of effluent and process water treatment plants for the Power, Oil & Gas (Refinery) and other industrial sectors, where it has achieved a strong reputation both within the Indian and overseas markets. Driplex Water Engineering Ltd is a leading turnkey solutions provider of water treatment plants, especially for the power sector. For the last three decades we have been synonymous with commitment and integrity in the field, having to our credit some of the biggest and prestigious projects. Driplex, in fact, has the dual distinction of being the largest water treatment plant provider to the power sector in India and also having the widest range of process and products for total services in water and ash management. Driplex was formed in 1974 and in this journey of 33 years we have catered to some of the biggest names in the Indian industry and had the distinction of being one of the few companies to provide water treatment plants and having its own fabrication facilities. However, we have also dared to take initiatives by venturing into research and development and having the capacity to experiment with design in industrial and waste management. 10

1.2 About ASME The American Society of Mechanical Engineers (ASME) was founded in 1880 in the U.S. by prominent mechanical engineers of the era, namely, Alexander Lyman Holley, Henry Rossiter Worthington, John Edison Sweet and Matthias N. Forney. It was founded to respond effectively and with mutual consensus, to the many boiler and pressure vessel failures, throughout the 19th century. Today, a worldwide engineering society, ASME is focused on technical, educational, and research issues. It holds technical conferences and professional development courses each year, and sets many industrial and manufacturing standards. 1.3The Codes and Standard The ASME Boiler and Pressure Vessel Code (BPVC) establishes rules of safety governing the design, fabrication, and inspection of boilers and pressure vessels and nuclear power plant components during construction. The objective of the rules is to provide a margin for deterioration in service. Advancements in design and material, and the evidence of experience, are constantly being added. The BPVC is “An International Historic Mechanical Engineering Landmark,” widely recognized as a model for codes and standards worldwide. Its development process remains open and transparent throughout, yielding “living documents” that have improved public safety and facilitated trade across global markets and jurisdictions for nearly a century. More than 100,000 copies of the BPVC are in use in 100 countries around the world, with translations into a number of languages. The boiler and pressure- vessel sections of the BPVC have long been considered essential within such industries as electric power-generation, petrochemical, and transportation, among others. The ASME/ANSI B16 - Standards of Pipes and Fittings covers pipes and fittings in cast iron, cast bronze, wrought copper and steel 11

Chapter 2: SUEZ COMPANY PROFILE 2.1 SUEZ PRODUCTS • High and Low Coded Pressure Vessels • LPG Storage and Mobile Tanks • Heat Exchangers • Process Tank & Vessels • Vacuum Chamber Dryers • Cryogenic Tanks And Vessels • Nitriding Pots (Furnace) • Storage tanks 2.2 CLIENTELE • Andhra Pradesh Power Generation Corp. Ltd. • Assam State Electricity Board • Bharat Heavy Electricals Ltd. • Chhatisgarh State Electiricity Board • Damodar Valley Corp. Ltd. • Essar Power Ltd. • Haryana Power Generation Corp. Ltd. • Karnataka Power Corp. Ltd. • Madhya Pradesh State Electricity Board • Neyveli Lignite Corporation Ltd. • National Thermal Power Corporation Ltd. • Punjab State Electricity Board • Rajasthan Rajya Vidyut Utpadan Nigam Ltd. • Reliance Energy Ltd. • Uttar Pradesh Rajya Vidyut Utpadan Nigam Ltd 2.3 INSPECTION & TESTING FACILITIES Surface Treatment Facilities Metal Blasting Painting 12

S No. Table 1 1. Facilities for NON-Destructive Test 2. 3. PENETRANT TEST OR DIE PENETRANT TEST 4. RADIOGRAPHIC TEST 5. 6. WELDING HARDNESS TEST HYDRO TEST WATER FILL TEST SPARK TESTING Table 2 2.4 FABRICATION FACILITIES PLATE BENDING COLD MILD STEEL SAINLESS STEEL Table 3 LIFTING CAPACITY WEIGHT(MT) QUANTITY 10 2 51 Table 4 CUTTING AND GRINDING EQUIPMENT Air Plasma Cutting Torch 3 sets Manual Gas Cutting Torch 4 sets Auto Gas Cutting Equipment 3 sets Portable Grinders 12 sets Flexible Shaft Grinders 12 sets Table 5 WELDING MACHINES 1 set 1 set GTAW/TIGW 1 set MMAW/MIGW SAW 13

Table 6 2 set 1 set 2.5 MACHINE SHOP 1 set 1 set Lathe Machine 1 set Radial Drill Machine Hank Saw Machine NUMBER MS Plate Cutting Machine 1 2 Rolling Machine 1 1 Table 7 1 1 2.6 WORK FORCE 3 1 DEPARTMENT 2 PLANT HEAD 60 HR QUALITY ENGINEER SAFETY ENGINEER MAINTENANCE ENGINEER IT ENGINEER PRODUCTION FINANCE DISPATCH LABOUR Table 8 14

Chapter 3: PRESSURE VESSELS A pressure vessel is a closed container designed to hold gases or liquids at a pressure substantially different from the ambient pressure. The pressure differential is dangerous and many fatal accidents have occurred in the history of their development and operation. Consequently, their design, manufacture, and operation are regulated by engineering authorities backed by legislation. For these reasons, the definition of a pressure vessel varies from country to country, but involves parameters such as maximum safe operating pressure and temperature. There are two types of pressure vessels: 1. Spherical pressure vessels 2. Cylindrical pressure vessels • Horizontal pressure vessel • Vertical pressure vessel Fig 1: Types of pressure vessel APPLICATIONS There are the following major applications of pressure vessels - (a) Chemical industry (b) Food and beverage industry (c) Oil and fire industry (d) Paper and pulp industry 15

(e) Power generation Chapter 4: STEP BY STEP FORMATION OF PRESSURE VESSEL 4.1 BRIEF STEPS FOR FABRICATION PROCESS 1. AutoCAD drawing and requirement of raw material 2. Marking on the raw material 3. Cutting of raw material 4. Rolling for shell 5. Circular disc prepared for heads 6. Cold forming through hydraulic press for heads 7. Heat treatment/Stress reliving of head 8. DPT (Die Penetration Test: NDT), Inspection of head 9. Grinding and v-edge preparation 10. Head and shell fit up 11. Welding 12. Radiography test (As per the joint efficiency & drawing requirement) 13. Cutting for nozzle 14. Nozzle installation with welding 15. Welding hardness test 16. Hydro test/Water fill test 17. Blasting inner surface of vessel 18. Application of rubber in inner surface/painting 19. Rubber curing through vulcanizer 20. Spark test and Addition test 21. Rubber hardness test 22. Final Physical inspection test 23. Blasting outer surface of vessels 24. Painting 4.2 IN PLANT PROCESSES 1. Cutting Process • Plasma arc cutting machine ➢ Combination of oxygen and pressure is used to cut. For small thickness and for Small cuts and easy to Handel. • oxygen LPG cutting torch ➢ Oxygen & LPG used to cut. For large thickness. • Band saw ➢ Coolant flow over the cutting tool to reduce heat. 16

2. Rolling process • Rolling machine ➢ Roller used to make shell for the vessel of required diameter. ➢ Thickness of shell sheet depends on the shape size and pressure 3. Flanging Process • This process is used to make head of the vessel by pressing and revolving method. 4. Welding Process • MIGW (Metal inert gas welding) ➢ It is generally used for large and thick materials. It employs a consumable wire that acts as both the electrode and the filler material. ➢ Pattern used circular, convex c, concave c, triangle and zig-zag. • TIGW (Tungsten inert gas welding) ➢ It is highly versatile, enabling industry professionals to join a wide range of small and thin materials. It uses a non-consumable tungsten electrode to heat the metal and can be used with or without filler. ➢ Compared to MIG welding, it is much slower. Additionally, welders require highly specialized training to ensure they achieve proper precision and accuracy. Produces strong, precise, and aesthetically pleasing welds. • SAW (Submerged Arc welding) ➢ A shielding gas is not required. The arc is submerged beneath the flux blanket and is not normally visible during welding. ➢ It is an automatic process ➢ Welding current (typically between 300 and 1000 amperes) 5. Blasting Process • This process is used to remove rust over the vessel. Very tiny metal balls are bombarded over and inside of the vessel. This will clear the surface of vessel. 6. Painting Process • Helps vessel not to rust, increase the life of it. 7. Drilling Process • Radial Drilling machine is mainly made for drilling holes in heavy jobs or work pieces. Since heavy jobs cannot move much, so the radial drilling machine is made in such a way that the tool of the machine can move any part of the heavy job without moving the job much. 17

Chapter 5: WELDING Welding is a process of joining two or more metal pieces as a result of significant diffusion of the atoms of the welded pieces into the joint (weld) region. Welding is carried out by heating the joined pieces to melting point and fusing them together (with or without filler material) or by applying pressure to the pieces in cold or heated state. Following welding methods, I have observed at SUEZ: 1. Gas Tungsten Arc Welding (GTAW, TIG) 2. Manual Metal Arc Welding (MMAW) 3. Submerged Arc Welding (SAW) 5.1 GAS TUNGSTEN ARC WELDING (GTAW, TIG) Gas Tungsten Arc Welding or Tungsten Inert Gas Arc Welding (GTAW, TIG) is a welding process, in which heat is generated by an electric arc struck between a tungsten non-consumable electrode and the work piece. The weld pool is shielded by an inert gas (Argon, helium, Nitrogen) protecting the molten metal from atmospheric contamination. The heat produced by the arc melts the work pieces edges and joins them. Filler rod may be used, if required. Tungsten Inert Gas Arc Welding produces a high quality weld of most of metals. Flux is not used in the process. 18

Fig 2: TIG WELDING 5.2 Manual Metal Arc Welding (MMAW) In this process an arc is drawn between a coated consumable electrode and the work piece. The metallic core-wire is melted by the arc and is transferred to the weld pool as molten drops. The electrode coating also melts to form a gas shield around the arc and the weld pool as well as slag on the surface of the weld pool, thus protecting the cooling weld pool from the atmosphere. The slag must be removed after each layer or once hardened, it should be chipped away to reveal the finished weld. Manual Metal Arc welding is still a widely used hard facing process. During welding the current remains constant, even if the arc distance and voltage change. The deposit rate is inferior to 1kg/h and the arc time is about 30%, due to the permanent need to change the consumable electrode. Metals that can be welded include mild steel in thicknesses from 1/16th up to 2 inches, stainless steel, and cast iron. Arc welding is an excellent method of repair work to cast iron castings. During the arc welding process is that the arc generates enough sustainable high intensity heat to melt the intended metal at any point it is directed to. Combined with the filler / electrode this action effectively fuses two pieces together. Applications: (a) Maintenance and repair industries. (b) Construction of steel structures (c) Weld carbon steel, low and high alloy steel, stainless steels, cast iron, aluminum, nickel and cooper alloys 19

FIG 3: MIG Welding 5.3 Submerged Arc Welding (SAW) Submerged-arc welding (SAW) is a common arc welding process that involves the formation of an arc between a continuously fed electrode and the work piece. A blanket of powdered flux generates a protective gas shield and a slag (and may also be used to add alloying elements to the weld pool) which protects the weld zone. A shielding gas is not required. The arc is submerged beneath the flux blanket and is not normally visible during welding. This is a well established and extremely versatile method of welding. Submerged arc welding is ideally suited to the longitudinal and circumferential butt welds required for the manufacture of line pipe and pressure vessels. 20

Fig 4: Fused flux Fig 5: SAW Applications: • Carbon steels (structural and vessel construction) • Low alloy steels • Stainless steels • Electrical Poles • Wind turbine • Surfacing applications (wear-facing, build-up, and corrosion-resistant overlay of steels) 21

Chapter 6: STRESS RELIEVING FURNACE Also called post welding heat treatment (PWHT) is used for relieving the stress from parts after machining and welding. This is used for C.S and Alloy parts. Machining and Welding induces stresses in parts. These stresses can cause distortions in the part long term. If the parts are clamped in service, then cracking could occur. Also whole locations can change causing them to go out of tolerance. For these reasons, stress relieving is often necessary. Some points to remember: 22

• Post weld heat treatment is designed to return a metal as near as possible to its prefabrication state of yield, ultimate tensile and ductility. • The rate of temperature rise, holding time at temperature and rate of cooling are vitally important. For this reason, furnace thermocouples must measure metal temperature, not furnace atmospheric temperature. • Heat treatment of any type must be a planned, systematic action. Poorly performed heat treatment can result in far more harm to material than any good which may result. • Test coupons must be subjected to the identical conditions as the vessel or part in order to obtain meaningful tensile and toughness (Charpy) test results. • The foregoing is a short generalization. Specific requirements are found in ASME Section II \"Material Specifications\" and in the \"Material Tables\", of the various Code sections. Fig 6 Stress Relieving Furnace Chapter 7: DESIGN CODES AND STANDARDS The following codes have been studied by me to the best of my abilities, during the course of my internship. The various sections of the Codes are in the form of detailed books, each section having a separate book, the main book having Cases and remedial actions, which have to be purchased from ASME by registered and established organizations involved in manufacturing activities or inspection and allied fields. [A] ASME BOILER AND PRESSURE VESSEL CODE SECTIONS: 23

BPVC-II Section-II Materials Part A — Ferrous Material Specifications Part B — Nonferrous Material Specifications Part C — Specifications for Welding Rods, Electrodes, and Filler Metals Part D — Properties (Customary) Part D — Properties (Metric) • The specifications for materials given are identical to the ASTM standards. • Filler metal procurement guidelines, carbon steel electrodes and of many other materials – Nickel, Tungsten, Aluminium, Zirconium. • Welding shielding gases have been specified. • Fluxes for brazing and braze welding and electrodes are given. • Stress values, yield strengths, thermal expansion values, modules of elasticity values can be referred. • Determination of shell thickness from standardized tables. BPVC-V Section-V Non-destructive Examination • Procedures have been laid out for NDTs giving their scope, equipments and methods of examination and inspection. • Detailed view of the radiographic examination, ultrasonic examination method for welds and materials, liquid penetrant examination, magnetic particle examination, eddy current examination, leak tests, acoustic emission exams has been provided. BPVC-VIII Section-VIII Rules for Construction of Pressure Vessels Division 1 Division 2 — Alternative Rules Division 3 — Alternative Rules for Construction of High Pressure Vessels • This Code contains mandatory requirements, specific prohibitions and non- mandatory guidance for construction activities. • The Code is not handbook and cannot replace education, experience and the use of engineering judgments, by design engineers. 24

• Lays down general requirements for all methods of construction and all materials and provides the scope of the Code. • Covers materials and design for plates, forgings, castings, bolts, nuts, methods of fabrication, design temperature & pressure, maximum allowable stress values, shell thickness, formed heads, inspection guidelines, pressure relief valves and guidelines for post weld heat treatments, radiography and ultrasonic examination. BPVC-IX Section-XI Welding and Brazing Qualifications • Relates the qualification of welders, welding operations, brazers and brazing operations and the procedures employed in welding or brazing in accordance with the ASME BPVC and the ASME B31 Code for Pressure Piping. • Establishes the basic criteria for welding and brazing which are observed in the preparation of welding and brazing requirements that affect procedure and performance – weld orientations, tests and examinations, braze orientations and various tests for the same. • Generally, a welding operation may be qualified by mechanical, bending tests, radiography of a tests plate or radiography of the initial production weld. Brazers or brazing operation may not be qualified by radiography. Chapter 8: BLASTING/PAINTING 1. BLASTING Blasting is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface, or remove surface contaminants. A pressurized fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material (often called the media).There are several variants of the process, using various media; some are highly abrasive, whereas others are milder. The most abrasive are shot blasting (with metal shot) and sandblasting (with sand). 25

Shot blasting works by propelling round materials known as shot media against a surface which in turn removes the contaminants of the surface and also can improve its finish. What type of shot media is used is a very important decision for the shot blasting process. The size and hardness of the shot material will dictate how much surface removal of the material being cleaned will occur. The type of material being cleaned will also play a role in the effectiveness of the shot blasting process. Typically, the shot material and size will be selected depending on the composition of the material whose surface is being shot blasted. Another important part of the shot blasting process is the propulsion method and the resulting velocity of the shot material. The most common way to propel the shot blasting media is through the use of a centrifugal wheel. To propel the shot blasting media, it is unloaded into a centrifugal wheel. Once the shot blast material has been accelerated by the wheel to the desired velocity, it is expelled from the wheel and into the shot blasting gun. Then the operator or machine holding the shot blasting gun directs the flow of the shot media to clean the material surface Fig 7: Blasting area 2. PAINTING 26

Fig 8: Painting Chapter 9: FINISHING / POLISHING Polishing and buffing are finishing processes for smoothing a work piece’s surface using an abrasive and a work wheel. Technically polishing refers to processes that use an abrasive that is glued to the work wheel, while buffing uses a loose abrasive applied to the work wheel. Polishing is a more aggressive process while buffing is less harsh, which leads to a smoother, brighter finish. Mirror bright finishes are obtained from buffed. Polishing is often used to enhance the looks of an item, prevent contamination of instruments, remove oxidation, create a reflective surface, or prevent corrosion in pipes. In metallography and metallurgy, polishing is used to create a flat, defect- free surface for examination of a metal's microstructure under a microscope. Silicon-based polishing pads or a diamond solution can be used in the polishing process. 27

Fig 9: Finishing The removal of oxidization (tarnish) from metal objects is accomplished using a metal polish or tarnish remover; this is also called polishing. To prevent further unwanted oxidization, polished metal surfaces may be coated with wax, oil, or lacquer. This is of particular concern for copper alloy products such as brass and bronze. The term chem-mechanical is used to describe action of corrosive slurry on silicon in a polishing process. Multiple rotating heads, each studded with silicon wafers, get forced against a large rotating buffing pad, which is bathed in corrosive slurry. Material removal at elevated temperature progresses first through oxidation, then through oxide removal by abrasion. This cycle repeats with each rotation of a head. Potassium Hydroxide and Silox (white paint-base) can be combined with deionized water to form such slurry. Polishing may be used to enhance and restore the looks of certain metal parts or objects such as vehicles, handrails, architectural metal and specially pipes are buffed to help prevent corrosion and to eliminate locations where bacteria or mold may reside. 28

Chapter 10: RUBBER CURING THROUGH VULCANIZER CURING The five basic methods used for curing rubber lining are autoclave, internal (pressure) steam, exhaust or atmospheric steam, chemical cure and hot water cure. The specific method used will depend on the nature and size of the vessel to be lined. Note that recommendations contained in this manual are suggested guidelines only. Actual cure times will depend on factors such as rubber thickness, vessel size and metal wall thickness, heat loss, ambient conditions and elevation. All cures should have proper temperature recording charts, and these should be properly identified with job number and date. 1. Autoclave Cure This refers to vulcanization where the rubber-lined vessel/part is placed inside a pressure vessel and subjected to controlled steam under pressure. An autoclave cure provides the best and most uniform cure and should be used whenever possible. Metal parts should be placed in the autoclave so that the best possible drainage of condensate from the rubber will be obtained. To obtain the most accurate and uniform cure, it is desirable to have the autoclave fully equipped with thermocouples and instrument controls on air pressure and steam. Sufficient boiler capacity should be available to raise the temperature from ambient to cure in a relatively short period of time. After finishing cure, it is recommended the rubber-lined vessel be cooled down by using water and/or air. Proper cool down of autoclaves will prevent post curing and preclude the possibility of cracking hard rubbers. The following cool-down procedures are suggested as recommended methods: • Cool down soft natural and synthetic rubbers one hour with air and water. • Cool down Triflex™ and hard rubber with air and water until autoclave temperature reaches 200°F (93°C). Continue a gradual cooling down of the autoclave with air and then with air and water. This cool down procedure can be modified, but a stepwise procedure will prevent cracking of the hard rubber. • During cool down it is important to maintain an air and water pressure equal to or greater than the steam pressure • All autoclaves should be equipped with temperature and pressure recorders. The recording charts should be properly identified and dated. • Precautions must be taken against stratification of steam and air particularly in large vulcanizers. During start-up the bottom exit valve 29

must be cracked open to allow a complete sweep of steam and cold air through the autoclave to avoid a cold bottom and subsequent under cured rubber. Chapter 11: NON-DESTRUCTIVE TESTS (NDTs) Non-destructive testing (NDT) is a wide group of analysis techniques used in an industry to evaluate the properties of a material, component or system without causing damage. The terms Non-destructive examination (NDE), Non-destructive inspection (NDI), and Non-destructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation. ➢ NDT Methods I witnessed the following methods in action at SUEZ-Driplex – 1) Surface techniques Die Penetrant Testing 2) Volumetric techniques – Radiographic Test 3) Welding Hardness test 4) Hydro testing 5) Rubber lining—Curing through Vulcanizer 6) Spark test 11.1 PENETRANT TEST (PT) OR DIE PENETRANT TEST (DPT) Dye penetrant inspection (DPI), also called liquid penetrant inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to locate surface breaking defects in all non-porous materials (metals, plastics, or ceramics). The penetrant may be applied to all non-ferrous materials and ferrous materials, although for ferrous components magnetic-particle inspection is often used instead for its subsurface detection capability. LPI is used to detect casting, forging and welding surface defects such as hairline cracks, surface porosity, leaks in new products, and fatigue cracks on in-service components. DPI is based upon capillary action, where surface tension fluid low penetrates clean and dry surface-breaking discontinuities. Penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has 30

been allowed, the excess penetrant is removed, a developer is applied. The developer helps to draw penetrant out of the flaw where a visible indication becomes visible to the inspector. Inspection is performed under ultraviolet or white light, depending upon the type of dye used - fluorescent or no fluorescent (visible). Fig 10: DPT Disadvantages Only for surface defects No information about depth of flaws Difficult to test on rough surface 31

Applications Used to locate cracks, porosity, and other defects that break the surface of a material and have enough volume to trap and hold the penetrant material. Liquid penetrant testing is used to inspect large areas very efficiently and will work on most nonporous materials. 11.2 RADIOGRAPHIC TEST Radiographic Testing (RT), or industrial radiography, is a non-destructive testing (NDT) method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation (high energy photons) to penetrate various materials. Either an X-ray machine or a radioactive source (Ir-192, Co-60, or in rare cases Cs-137) can be used as a source of photons. Neutron radiographic testing (NR) is a variant of radiographic testing which uses neutrons instead of photons to penetrate materials. Very different from X-rays, because neutrons can pass with ease through lead and steel but are stopped by plastics, water and oils. X-rays are used to produce images of objects using film or other detector that is sensitive to radiation. The test object is placed between the radiation source and detector. The thickness and the density of the material that X-rays must penetrate affect the amount of radiation reaching the detector. This variation in radiation produces an image on the detector that often shows internal features of the test object. Q When one of following conditions is existing, you need to do the full radiography: All butt welds in vessels used to contain a lethal substance All butt welds in vessels in which the nominal thickness exceeds specified values All butt welds in unfired steam boilers with design pressure > 50 psi All category A and D butt welds in a vessel when “Full Radiography” is optionally selected Fig 11: Radiography Area 32

Fig 12: Radiography test Applications Used for the inspection of almost any material for surface and subsurface defects. X-rays can also be used to locates and measures internal features, confirm the location of hidden parts in an assembly, and to measure thickness of materials. 11.3 WELDING HARDNESS TEST This NDT (non-destructive test) exist to ensure a weld zone or structural loading area isn't weak. If the Weld joint or structural component is weak, then plastic deformations occur. Next, just like any other measurement system, hardness testing uses several well-established engineering standards. There's the Brinell scale, the Rockwell scale and several other notable hardness gauging standards in place. As for the test it can be as simple as an indentation or as complex as a digitally measured read out. Used for non-destructive metallurgical assignments, hardness testing HT instrumentations is available in an easy to mobilise form. The gear looks like a standard multimeter, a piece of kit found in an electrician’s toolbox, but it's cap abilities are entirely different. Instead of digitally measuring voltages and currents in wires, portable hardness testers use specials crops to metallurgically examine metal surfaces. Ultrasonic technology is one solution here, but there are also impact bolts, moving parts that strike surfaces. In this case, it's the rebound velocity of the spring- loaded rod that supplies hardness data to the portable tester. 33

Fig 13: Hardness test Main application • The installed machinery and permanently assembled parts • Die cavity of moulds • Heavy and large work piece • Failure analysis of pressure vessel 11.4 HYDRO TEST Hydrostatic (Hydro) Testing is a process where components such as piping systems, gas cylinders, boilers, and pressure vessels are tested for strength and leaks. Hydro tests are often required after shutdowns and repairs in order to validate that equipment will operate under desired conditions once returned to service. In order to conduct the test, the vessel is filled with water and loaded it into a sealed chamber (called the test jacket) which is also filled with water. The vessel is then pressurized inside the test jacket for a specified amount of time. This causes the vessel to expand within the test jacket, which results in water being forced out into a glass tube that measures the total expansion. Once the total expansion is recorded, the vessel is depressurized and shrinks to its approximate original size. As the vessel deflates, water flows back into the test jacket. Sometimes, the vessel does not return to its original size. This second size value is called permanent expansion. The difference between the total expansion and permanent expansion determines whether or not the vessel is fit-for service. 34

Typically, the higher the percent expansion, the more likely the vessel will be decommissioned. The pressure, temperature and the amount of chlorine added to the water are set according to the AutoCAD design requirements. The purpose of the test is if there are no cracks, pinholes, or other discontinuities in the welds. The second purpose of the test is to confirm the mechanical strength of the tank. Fig 14: Hydro test 11.5 WATER FILL TEST In this test water is filled into the vessel just to check if there any cracks or leaks in the vessel. Pressure is not required in this test. This test is commonly used to inspect/check small vessels. 35

Fig 15: Water fill test 11.6 SPARK TEST Before and after rubber lining is cured, it must be tested with a spark tester. The purpose of the test is to determine the presence of pinhole leaks, punctures, cuts, etc., that expose passages to base metal. There are various models of spark testers used to test for leaks in rubber. The commonly used ones consist of a generator with a Tesla coil added to the circuit or a direct current tester that uses a battery for the power supply. Output voltage can be fixed or variable depending on the particular test equipment. A variety of electrode accessories are available, but normally a T or L-shaped electrode is used on large surfaces. It is recommended that the end of the probe be used on overlapped or skived joints Keep electrode in light contact with rubber and move back and forth at the rate of approximately 1 ft/sec. It is important that the electrode be kept moving without stopping too long in one position; otherwise, there may be a chance of dielectrically breaking down the rubber. During testing, the spark will be bluish and the sound will be an even buzzing. If fault or pinholes are present, the corona discharge will start to fade and the spark will change to a white color. The white spark will then be concentrated in a line to the pinhole, etc., and the sound will change to a sputtering 36

and cracking noise. No moisture should be present at the time of testing and all surfaces must be free of grit, dirt or foreign matter. Fig16: Spark test 37

Chapter 12: PRESSURE VESSEL HEADS (TORISPHERICAL) The end caps on a cylindrically shaped Pressure Vessel are commonly known as heads. They are made on hydraulic presses. Fig 17: Types of pressure vessel shell The shape of the heads used can vary. The most common head shapes are: (a) Ellipsoidal head This is also called a 2:1 elliptical head. The shape of this head is more economical, because the height of the head is just a quarter of the diameter. Its radius varies between the major and minor axis. (b) Torispherical head These heads have a dish with a fixed radius (r1), the size of which depends on the type of torispherical head. The transition between the cylinder and the dish is called the knuckle. The knuckle has a toroidal shape. The most common types of torispherical heads are: 38

Fig 18: Torispherical head (c) Hemispherical head A sphere is the ideal shape for a head, because the pressure in the vessel is divided equally across the surface of the head. The radius (r) of the head equals the radius of the cylindrical part of the vessel. Fig 19: Hemispherical head (d) Conical head This is a cone-shaped head. Fig 20: Conical head 39

(e) Flat head This is a head consisting of a toroidal knuckle connecting to a flat plate. This type of head is typically used for the bottom of cookware. Fig 21: Flat head Chapter 13: Support for Pressure Vessel Type of support used depends on the orientation and pressure of the pressure vessel. Support from the pressure vessel must be capable of withstanding heavy loads from the pressure vessel, wind loads and seismic loads. Pressure on pressure vessel design is not a consideration in designing support. Temperature can be a consideration in designing the support from the standpoint of material selection for the different thermal expansion. Various types of support that used to support the pressure vessel are as follows: 1. Saddle Support 2. Leg Support 3. Lug Support 4. Skirt Support 1. Saddle Support: Horizontal pressure vessel (Fig. 1) is generally supported by two advocates of saddle support. Wide saddle supports the weight of the ultimate burden on a large area on the shell to prevent excessive local stresses on the shell above the supporting point. The width of the saddle between the detail designs is determined based on the specific size and condition of the pressure vessel design. 40

Fig 22 - Pressure Vessel Horizontal with Saddle Support 2. Leg Support: Small vertical pressure vessel is generally supported by the a leg at the bottom of the shell. Comparison between the maximum lengths of the support leg with a diameter of vessel is usually 2:1. Ring reinforcement pad is used to provide additional reinforcement of local and load distribution, where the local stresses that occur shell can be overdone. The sum of the leg is needed depends on size and weight received vessel. Support leg is also commonly used in pressurized spherical storage vessels. Fig 23: Leg Support 41

3. Lug Support: Lug Support in a pressure vessel can also be used to support the vertical pressure vessel. Lug Support is limited to a small vessel with a diameter of up to medium diameter (10-10 ft). With a ratio of height to vessel diameter is 2:1 to 5:1. Lug often used to support vessel located on top of steel structures. Lug usually bolted on the horizontal structure to provide stability against the loads; however, bolt holes are often given the gap to provide radial thermal expansion of freedom in the vessel. Fig 24: Lug Support 4. Skirt Support: Vertical cylindrical pressure vessels which are high are generally supported by the skirt. Skirt support is part of a cylindrical shell, one of them at the bottom of the body vessel or the bottom head (for the cylindrical vessel). Skirts for spherical vessel on the vessel are closer to the center of the shell. Fig 25: Skirt Support 42

Chapter 14: PRESSURE VESSEL SHELL The Shell contains the pressure and consists of plates that have been welded together with an axis. Horizontal drums use shells with a cylindrical shape. The Head. This is what closes off the end of a pressure vessel. Curved heads have less weight, cost less and have more strength than flat heads. Fig 26: pressure vessel shell 43

Chapter 15: ASSIGNMENT 15.1 Selection of material, IS 2062 (Indian Standard Structural Steel) 1. Steel grade Steel is a combination of iron and carbon, but there are more than 3,500 different grades of steel. Steel’s grade is determined by the amount of carbon, what other alloys it contains, and the way it has been processed. 304 stainless steel is the most common form of stainless steel used around the world due to excellent corrosion resistance and value. 304 can withstand corrosion from most oxidizing acids. 44

2. Quality A, BR, BO, C are the type A to C for grade E 250 to E 275. The Charpy Impact Test can measure material toughness. The toughness of a material can be measured using a small specimen of that material. A typical testing machine uses a pendulum to strike a notched specimen of the defined cross-section and deform it. The Charpy impact test, also known as the Charpy V-notch test, is a standardized high strain-rate test which determines the amount of energy absorbed by a material during fracture. Absorbed energy is a measure of the material's notch toughness. 3. Carbon equivalent The carbon equivalent is a measure of the tendency of the weld to form martensite on cooling and to suffer brittle fracture. Martensite is a very hard form of steel crystalline structure. When the carbon equivalent is between 0.40 and 0.60 weld preheat may be necessary. When the carbon equivalent is above 0.60, preheat is necessary, postheat may be necessary. 45

4. Chemical analysis • Ladle analysis A little molten metal is collected in ladle and sent to lab for chemical analysis. Once the test confirms that the composition is correct. This is ladle analysis • Product analysis 46

5. Mechanical tests • Tensile test • Bending test • Impact test • Y groove crackability test: IS10842 (Only for E 250 C, thickness 12mm or above) • Re-test (If a test does not give the specified results, two additional tests shall be carried out at random on the same lot) 15.2 Stress Analysis of Pressure Vessels Stress analysis is an engineering discipline that determines the relationship between externally applied forces and their effects in form of stress generated within the material and structural member. For any stress analysis, an usually approach is made that component or part being analysed must be safe economical and design point of view. In the analysis of vessel, it is not considered to build a mathematical model with providing step by step approach to the design of ASME codes but just to determine or calculate governing stress being produced with in vessel and its attachment, supports and respective parts. The starting place for stress analysis is to determine all the design conditions for a given part and the type of loading to find the corresponding stresses produced in vessel. The designer must be aware of type of loadings and time period and area of vessel that is under loading and their effects on safety of vessels. So, in short the significance and interpretation of stresses in combined or individual way may be determined by two factors: • Utilization of stress failure theory • Categories and types of Loadings 47

15.2.1 Membrane stress Analysis Pressure vessels can be categorized in the form of spheres, cylinders ellipsoids and on the basis of membrane thickness they may be thick or thin depending upon thickness to diameter ratio and usually if (R/T >10) then vessels are referred as thin pressure vessels and vice versa and member thickness is assumed to be uniform through entire length. Now here we are considering we are considering very basic shape of pressure vessels that is being subjected to internal pressure and neglecting the types of heads, closing the vessel, effects of supports, variations in thickness and cross section, nozzles, external attachments, and overall bending due to weight, wind and vessel. Here two types of geometries of thin-walled pressures will be considered for stress calculations • Cylindrical pressure vessel • Spherical Pressure Vessel 15.2.1.1 Cylindrical Pressure vessels Thin wall pressure vessels are very less affected by bending stresses and cylindrical pressure vessels are less efficient because of varying pressure stresses in different directions and because of attachment of additional reinforcements on closing end caps however, these vessels are convenient to fabricate and transport. 15.2.1.1.1 Assumptions for Cylindrical pressure vessels • Wall assumed to be very thin as compared to other dimensions • Stress distribution must be uniform along entire length • Geometry and loading must be cylindrically symmetric • Internal Pressure denoted by p is uniform and everywhere positive and is above than atmospheric pressure. • Features that may effect symmetric assumptions may be ignored like closing ends. 15.2.1.1.2 Explanation A cylindrical pressure with wall thickness, t, and inner radius r is considered a gauge pressure p exists within the vessel by the working fluid (gas or liquid). For an element sufficiently removed from the ends of the cylinder and oriented as shown in Figure 12.1, two types of normal stresses are generated: hoop _h, and axial _a, that both exhibit tension of the material. 48

For the hoop stress, consider the pressure vessel section by planes sectioned by planes a, b, and c shown in fig. A free body diagram of a half segment along with the pressurized working fluid is shown in Note that only the loading in the x- direction is shown and that the internal reactions in the material are due to hoop stress acting on incremental areas, A, produced by the pressure acting on projected area, Ap. For equilibrium in the x-direction we sum forces on the incremental segment of width dy to be equal to zero such that Where dy = incremental length, t = wall thickness, r = inner radius, p = gauge pressure, and h is the hoop stress. For the axial stress, consider the left portion of section b of the cylindrical pressure vessel shown in Figure 12.2. A free body diagram of a half segment along with the pressurized working fluid is shown in Fig. 12.4 Note that the axial 49

stress acts uniformly throughout the wall and the pressure acts on the and cap of the cylinder. For equilibrium in the y-direction we sum forces such that: Since this is thin walled pressure with a small t and t2 and can be neglected such that after multiplication. Where ro= inner radius sa is the axial stress. Noting that equations it is very much clear that hoop stress is twice as large as the axial stress (h=2a) Consequently, when fabricating cylindrical pressure vessels from rolled-formed plates, the longitudinal joints must be designed to carry twice as much stress as the circumferential joints. 15.2.2.1 Spherical Pressure Vessels A spherical pressure vessel can be analysed in a similar manner as for the cylindrical pressure vessel. As shown in Figure, the “axial” stress results from the action of the pressure acting on the projected area of the sphere 50