Variable Spring Hanger Supports are widely used in critical pipe systems for their load-bearing capability allowing thermal movements. In Caesar II, We can easily design a variable spring hangersupport by double-clicking the checkbox for the hanger auxiliary. The software follows the below-mentioned steps to select its spring.
CAESAR II puts rigid support at the hanger location and does a weight analysis to find out the weight that the support should carry. This load is used as the Hot Load (HL).
CAESAR II applies a force equal to that Hot Load (but not stiffness (k)) at the hanger location and then runs an operating analysis. This tells CAESAR II how much that location wants to move vertically (y) under the operating loads. So this becomes the “theoretical” hanger movement. Now, the “theoretical” cold load is calculated as Cold Load (CL) = HL + ky.
CAESAR II adds the CL as a force and the spring stiffness as a restraint stiffness to all load cases of the model and then runs all the normal load cases.
In this article, We will design a variable spring hanger support by following the above Caesar II Algorithm. The steps for manual spring hanger design are explained below with an example.
Manual Spring Hanger Design Procedure
The example problem is shown in Fig. 1.
Fig. 1: Variable Spring Hanger Design without Caesar II Hanger Auxiliary
Let’s assume that we will design a variable spring hanger support at node 15 as shown in Fig. 1A. At node 20, the pipe is Resting.
To design the spring support, A weight run is to be taken with a Rigid double-acting Y restraint at node 15 (without friction). Assume the load computed to be 3540 N.
Now apply that force (3450 N) at node 15 in an upward direction and run an operating case. Note the lift-off at 20 as shown in Fig. 1C. Observe the travel at 15 let us assume it here as 5.785 mm.
In case, there is no lift-off in the nearby supports (Node 20) then the above-computed values will be the final Hot Load and Spring Travel.
But as the support at node 20 is lifted off, Remove the support at node 20 and Run a weight case with a rigid double-acting Y restraint at node 15 (without friction). Refer to Fig 2A. Assume, the load experienced at node 15 is now 3651 N.
Fig. 2: Manual Spring Hanger Support Design Example
Now, an operating case runs are to be taken with 3651 concentrated loads (Fig. 2B) in an upward direction at 15. Suppose this time the travel is 5.829 mm.
Hence, for the above system Computed Hot load = 3651 N. Computed theoretical travel from cold to hot =5.829 mm.
On the basis of the computed hot load and the thermal travel one can estimate the maximum permissible spring rate as depicted below:
kmax =(Var X HL)/ |yth |——————– (a)
Where Var is the maximum permissible variation.
Now the computed hot load can be located in the columns of the spring support catalog table from the vendor. For that spring size select the spring series with a spring rate less than or equal to that calculated by (a).
The cold load can be calculated by
Cold Load= H.L + ky
The cold load calculated above is then located in the table under the same spring size. If the cold load does not fall under the column of the selected size then a different spring series or spring of an adjacent size is to be selected.
Note that when specifying hanger’s hot and cold loads, It is important to add the anticipated hardware weights to these values especially if it is significant like trapeze assembly or large clamps, etc. The prime requirement being the necessity of the hanger to support hardware as well in order to avoid imbalance in the system by the weight of hardware.
Reciprocating pumps are used where the delivery pressure of the fluid is quite large. In this article, we will discuss on Single-acting Reciprocating Pump. As the name itself indicates that it has a single component of the suction valve, delivery valve, suction pipe, and delivery pipe along with a single piston.
Let’s dive into the article of Reciprocating Pump along with its Introduction, Definition, Diagram, Parts, Working Principle, Advantages, Disadvantages, and Applications.
Introduction of Reciprocating Pump:
Reciprocating Pump is a Positive Displacement type pump that works on the principle of movement of the piston in forwarding and backward directions whereas the Centrifugal pump uses the kinetic energy of the impeller to supply the liquid from one place to another place.
Who Invented Reciprocating Pump?
A Greek inventor and mathematician Ctesibius invents Reciprocating Pump in 200 BC.
Definition of Reciprocating Pump:
It is a machine that converts mechanical energy into hydraulic energy.
Reciprocating pumps are in use where a certain quantity of fluid (mostly sump) has to be transported from the lowest region to the highest region by the application of pressure.
For Example,
When you go to the water servicing of the bike, you can see that the water that is being used is collected from the sump only, and by the application of pressure via a nozzle, water is sprayed onto the vehicle.
Reciprocating Pump Diagram:
The diagram of the Reciprocating Pump was displayed below.
Parts of Reciprocating Pump:
The Parts of the Reciprocating Pump are as follows.
An Explanation for the parts of the Reciprocating Pump:
The explanation for the parts of the Reciprocating pump is as follows.
Water Sump:
It is the source of water. From the sump, water is to be transported to the delivery pipes by the usage of the piston.
Strainer:
It acts as a mesh that can screen all the dirt, dust particles, etc. from the sump. If there is no strainer, then the dirt or dust also enters into the cylinder which can jam the region and affects the working of the pump.
Suction Pipe:
The main function of the suction pipe is to collect the water from the sump and send it to the cylinder via a suction valve. The suction pipe connects the water sump and the cylinder.
Suction Valve:
It is a non-return valve which means it can take the fluid from the suction pipe and send it to the cylinder but cannot reverse the water back to it. In this sense, the flow is unidirectional.
This valve opens only during the suction of fluid and closes when there is a discharge of fluid to the outside.
Cylinder:
It is a hollow cylinder made of cast iron or steel alloy and it consists of the arrangement of a piston and piston rod.
Piston and Piston rod:
For suction, the piston moves back inside the cylinder and for discharging of fluid, the piston moves in the forward direction.
The Piston rod helps the piston to move in a linear direction i.e. either the forward or the backward directions.
Crank and Connecting rod:
For rotation, the crank is connected to the power source like an engine, motor, etc. whereas the connecting rod acts as an intermediate between the crank and piston for the conversion of rotary motion into linear motion.
Delivery Pipe:
The function of the delivery pipe is to deliver the water to the desired location from the cylinder.
Delivery valve:
Similar to the suction valve, a delivery valve is also a Non-return valve. During suction, the delivery valve closes because the suction valve is in opening condition and during Discharge, the suction valve is closed and the delivery valve Is opened to transfer the fluid.
These are the various components of the Reciprocating pump. Let’s understand the working principle of it.
By Ben Franske, Reciprocating Pump
Working Principle of Reciprocating Pump:
When the power supply is given to the reciprocating pump, the crank rotates through an electric motor.
The angle made by the crank is responsible for the movement of the piston inside the cylinder. By referring to the above diagram, the piston moves towards the extreme left of the cylinder when the crank meets position A i.e. θ=0.
Similarly, the piston moves towards the extreme right of the cylinder when the crank meets position C i.e. θ=180.
A partial vacuum in the cylinder takes place when the piston movement is towards the right extreme position i.e. (θ=0 to θ=180.) and that makes the liquid enter into the suction pipe.
This is due to the presence of atmospheric pressure on the sump liquid which is quite less than the pressure inside the cylinder. Therefore, due to the difference in pressure, the water enters the cylinder through a non-return valve.
The water which stays in the volume of the cylinder has to be sent to the discharge pipe via the discharge valve and this can be done when the crank is rotating from C to A i.e. (θ=180 to θ=360) which moves the piston in the forward direction.
Due to the movement of the piston in a forward direction, the pressure increases inside the cylinder which is greater than the atmospheric pressure.
This results in the opening of the delivery valve and closing of the suction valve.
Once the water comes into the delivery valve, it cannot move back to the cylinder because it is a unidirectional valve or non-return valve.
From there, it enters into the delivery pipe so that it can be sent to the required position.
Therefore, in this way, the water is sucked and discharged from the sump to the desired location through the piston inside the cylinder.
Reciprocating Pump Advantages:
The advantages of Reciprocating Pump are as follows.
No priming is needed in the Reciprocating pump compared to the Centrifugal pump.
It can deliver liquid at high pressure from the sump to the desired height.
It exhibits a continuous rate of discharge.
It can work due to the linear movement of the piston whereas the centrifugal pump works on the rotary velocity of the impeller.
Reciprocating Pump Disadvantages:
The disadvantages of Reciprocating Pumps are as follows.
The maintenance cost is very high due to the presence of a large number of parts.
Managing a project is not so easy. There is every possibility that something can go wrong. Starting from the project initiation to its successful closure, every project has to go through several phases of the project life-cycle. Depending on the type and scope of projects, the number and name of these project phases may vary. Still, there are some main phases that are applicable to all types of projects. Each project phase has its own goals, deliverables, activities, and processes that must be completed before moving to the next one. In this article, we will explore each phase of an oil and gas project in more detail.
What is a Project?
A project is a series of tasks that need completion to get a specific outcome. Every project is unique in that it is not a routine operation. A specific set of inputs & outputs are designed for a singular goal in the form of a project or service.
Projects can range from simple to complex. Depending on the complexity of the project, one or more people can manage the project. Projects are often described by a project manager or executive of the client. It is required to finish the work within a time frame because every project has its deadlines.
What is Project Management?
Project management is the art of planning, controlling, and executing a project to ensure a successful outcome. The primary challenge of project management is to achieve all the project goals within the deadlines.
The aim of project management is to produce a complete project meeting the client’s objectives. Often the goal of project management is to shape or reform the client’s objectives. The client’s objectives influence all decisions of project managers, designers, contractors, and sub-contractors.
Project Life Cycle
A project life cycle specifies the sequences of stages that a project involves from its initiation to its closure. Refer to Fig. 1 which clearly explains the Project Life Cycle for any project.
Fig. 1: Project Life Cycle
Project Phases / Stages
There are 12 major phases/stages involved in oil & gas projects. Refer to Fig. 2 which specifies all these project phases.
Fig. 2: Phases of a Project
What is a Feasibility Study of a Project?
A Feasibility Study/analysis is a process to determine the validation of an idea. The feasibility Study ensures that a project is legally, technically, and economically justifiable. It tells the owner/client whether a project is worth the investment.
In some cases, a project may not be beneficial. Various Parameters like requiring too many resources, low market demand, and unavailability of nearby resources, etc. can contribute to such assessment. Such projects are not profitable.
Types of Feasibility
Four types of feasibility assessments are done before proceeding with a project. These are:
Economic Feasibility.
Legal Feasibility.
Operational Feasibility.
Scheduling Feasibility.
Concept Development / Conceptual Design
Concept development is the first step of the multiphase process involved in creating a new product. For any project or product design process, Conceptual design is the very first stage. The drawings or models are used to describe the proposed product. A set of integrated ideas and concepts are decided in this stage.
Conceptual design is a set of disciplines that contributes to identifying the optimal design at nominal operating conditions of industrial processes/products in the field of engineering.
It evaluates the best design variables and operating conditions to maximize the profit of the organization.
Pre-FEED develops the project design basis and places boundaries to constrain and define the concept. This process can be simplified by the following activities:
A design basis is developed that outlines the operating characteristics of the project.
The technical and economic feasibility of the design basis will be determined during this exercise.
The allocation of additional funds is evaluated for proceeding with engineering and design.
Project boundaries are developed to deal with rules and regulations, National and local laws, governance, and content issues.
FEED or Front End Engineering Design is the most basic engineering conducted after the completion of the conceptual design and feasibility study. At this stage, various studies take place to figure out technical issues and estimate rough investment costs.
This work is normally contracted to the EPC (Engineering, Procurement, and Construction) contractors. The final product of this stage is the FEED Package. FEED package amounts to dozens of files and will be the basis of bidding for the EPC Contract. It is important to reflect the client’s intentions and project-specific requirements in the FEED Package. It avoids significant changes during the EPC Phase. It is essential to maintain close communication with the client. Sometimes, the client stations at the Contractor’s office during the work execution.
Detailed engineering is a study, which creates every aspect of project development. Detailed Engineering includes all the studies before the project construction starts. Detail engineering includes
the extraction of all the essential information from the basic engineering drawings/FEED
calculations to provide the exact drawings in detail for the production, fabrication & erection items
the details of the entire project along with the precise bill of quantities and specifications for each of the equipment.
It also involves 3D modeling.
Deliverables of Detailed Engineering
Equipment List.
Process data-sheet.
Management/review of vendor drawings.
Thermal rating and vibration analysis of heat exchangers.
The Procurement phase of a project involves a series of activities and processes by the purchase or procurement team. It is necessary to acquire the necessary products or services from the best suppliers/vendors at the best price and quality. Such products include raw materials, equipment, machinery, instruments, etc.
An effective procurement strategy involves:
a financial plan to manage the budget.
a good plan to manage the workflow and production deadlines.
keeping everything aligned with the client’s objectives.
ensuring a smooth supply of required items for construction.
In the oil and gas industry, procurement plays an important role in ensuring the supply of products, items, and services within budget allocation, ensuring on-time delivery on-site and cost savings without compromising quality and safety.
Procurement Cycle
In Procurement, the Procurement cycle lists the key steps in a cyclical order. This makes understanding each procurement step easier. Refer to Fig. 3 for a typical Procurement Cycle with important procurement steps.
Fig. 3: Typical Procurement Cycle
Note that Pre-FEED, FEED, Detailed Engineering, and Procurement are performed/executed by the EPC Contractor
Onsite and Offsite Fabrication
Offsite Fabrication is a process of fabrication and assembly of parts or systems at a location away from the project like a workshop. Offsite fabrication provides a cost-benefit, allowing the assembly of units that would not be able to be fabricated on-site due to cost, tooling, availability of resources, or space restrictions. Nowadays it is at a peak in the industry.
Onsite Fabrication is the fabrication held at the project site. After the offsite fabrication, it is still required to do fabrication work at the site for connecting the different pieces of equipment, pipes, and other systems for installation purposes.
Note: Fabrication is executed by the Contractor/vendors.
Construction Phase
Construction is the activity of putting different elements and objects together. It should follow a detailed design plan, and the installation drawing to create a structure, equipment, building, etc. While constructing large structures/buildings, A clear action plan is a must.
One should know the dimensional coordinates of the specific location. It involves clearing, excavating, and leveling the land. It also involves other activities associated with the structure, building, and other properties of the plant.
Erection is the process of cleaning and preparing the place for the installation of a new machine or equipment. It involves arranging equipment/elements or tools for the installation purpose. This is part of the mechanical completion.
Installation is the process of assembling the different parts of the system by welding or mechanical joints. The process involves connecting the electrical connections for the creation of a single system.
Mechanical completion:
The activities involved in the installation of the equipment and piping system are known as mechanical completion. It is done to make sure everything is installed as per the drawing and after the clearance of this stage commissioning and testing occurs.
Note: Construction, Erection, and Installation are executed by the Contractor.
Pre-commissioning Phase
Pre-Commissioning activities start after the system achieved mechanical completion. Pre-Commissioning activities include cleaning, flushing, drying, leak test, and hydro-testing of the equipment, piping system, and other operating systems. Sometimes pre-commissioning activities are included in mechanical completion but this depends again on the contract conditions or the requirement of the project.
Note: Pre-commissioning & commissioning is executed by the Contractor and the operator of the plant.
Commissioning Stage
Commissioning is a verification process used to confirm that a facility or the process has been designed, procured, fabricated, installed, tested, and prepared for operation or production by the blueprint, design drawings, and specifications provided by the client. It is the second last stage of the project.
Note: After the completion of the commissioning, if no error is found in the system then the referred drawing becomes an “as-built drawing”.
As-built drawing: This is the final drawing sheet of the plant and is used for future modification, maintenance, and review purposes.
Start-up Phase
After the successful completion of the testing of the processing system or the plant, It is time for the green signal to start production.
Piping Material Take Off (MTO) is a crucial process of any piping project. It plays an important role in estimating costs, planning resources, and ensuring the smooth execution of the project. Accurate MTOs are the foundation of successful piping projects. Piping Specifications, Fittings, Valves, Special Items, etc are the main components of piping MTO. The main purposes of piping material take-off are:
Cost Estimation: Piping MTOs enable accurate cost estimation, helping project managers budget effectively and prevent cost overruns.
Resource Planning: With a clear understanding of required materials, project teams can plan resources efficiently, avoiding delays due to material shortages.
Procurement Guidance: MTOs guide the procurement process, ensuring that the right materials are sourced in the correct quantities and specifications.
It’s an essential part of the project estimation process. The material take-off sheet contains a list of all the materials required to complete the project. This list does not include any assets, such as equipment, machinery, and tools. These assets will also be required to complete the job of the project. MTO is prepared line-wise.
Note: Material take-off is different from the Bill Of Material (BOM) and Bill Of Quantity (BOQ).
Information in a Material Take-off Sheet
Material take-off seems to be straightforward but is quite complex in practice. As material take-off helps in the construction cost estimation process, it is necessary to understand what information should be added to the MTO sheet.
List of the Information available in the Material Take-Off sheet is as follows:
Note: It can be arranged at the convenience of the users.
What is the Bill of Material (BOM)?
In the world of piping, the Bill Of Materials (BOM) often appears on a piping isometric drawing. The BOM contains the list of all the components required to fabricate and construct the line. Piping Isometric provides the list of BOM for a particular line. The piping bill of material is not used for purchasing. It is used to provide the required material from the warehouse to the fabricator for the construction of the piping system as per the isometric drawing. BOM is a document used at the site during the construction phase.
What is the Bill of Quantity (BOQ)?
The Bill Of Quantity (BOQ) is a tendering document. It covers the scope of materials for the entire piping components of the project. However, it is not the final list as it may change further during the MTO preparation at different stages.
BOQ is produced at the starting stage of the project, before construction drawings. Thus, it will not reflect the exact quantity of materials required for the project. But this document finds its use for tendering or bidding.
Stages for Piping Material Take-Off
There are three stages or sessions of material take-off in a process piping project.
Preliminary,
Secondary, and
Final.
There may be more stages depending on the project’s complexity. Sometimes, they are known as zero-level MTO, 30%, 50%, 70%, 90%, final MTO, etc.
Preliminary MTO
The preliminary MTO is prepared at a very early stage in the design process. At this stage, there is usually limited availability of the information. A preliminary MTO is prepared once the P&IDs and Plot plan are approved by the client or have been issued for approval. This is done long before there is any detailed design work started on the 3D modeling software. The preliminary piping material take-off is generated only when the Plot Plan is issued to the client for approval or it is “Approved”. The preliminary piping mto must be done by an experienced piping engineer/designer.
Use of the Preliminary MTO
There are two main reasons for preparing the preliminary MTO:
Cost estimation
Bidding of the material/ Request for quotation (RFQ)
Documents required for Preliminary MTO are
P&ID
PMS (Piping Material Specification)
Steps for Preliminary MTO Preparation
Identify the numbers of lines, line classes/specs, and the line size from the P&ID.
On the MTO sheet, enter the line number, line class, and line size.
Identify the potential line routing of each line shown on the P&ID and route the line on the plot plan (we can also refer to a similar old project for reference.
From the line routed on the plot plan, identify the approximate pipe length and estimate the numbers of fittings like elbows, tees, reducers, flanges, etc, and group them size-wise. (The length of the pipe and number of Elbows are not fixed at this stage of MTO).
Identify the numbers of the valve from the P&ID directly.
Estimate the High-point vent and low-point drain as per your guess and experiences.
Enter the detail of the piping components in the MTO sheet following the sequence of the component, you can refer to Fig. 1.
Now, go to the next line and repeat the same procedure.
Highlight each line on the P&ID as you complete the above process, that will help in identifying the undone lines.
Cross-check after completion.
Secondary MTO
When there is significant progress on the piping design, The secondary MTO is prepared. It may include the piping design done on 3D modeling software or 2D software. It must be done early enough to ensure that the procurement of the piping materials could fit the project schedule. This is prepared with the help of the material control group.
Secondary MTO is prepared with the help of PDMS/PMS/E3D by extracting the isometric from the ISO-draft module. This software gives the actual length of the pipes and the number of elbows used in the piping system. It is very difficult to find such information in the preliminary MTO.
Use of the Secondary MTO
There are mainly two reasons for preparing the secondary MTO
To update the quantities, so that purchase orders for piping items can be issued.
To update the project cost estimate.
Final MTO
The final piping MTO will identify the actual final material quantity. All items missed in the last MTO or modified due to design modification will be captured. It clears the final material cost required for the project.
The final MTO is prepared when the last isometric has been drawn, checked, approved, and issued. It proceeds in the same manner as the secondary MTO.
Use of the Final MTO
Final MTO is used for updating the last purchase order to fulfill the final need of material so as not to exceed spare material.
Note: MTO stages are not limited to these three only, if there is any modification occurs in the design at any stage of the project, then it is required to update the latest prepared MTO.
Difference Between BOM and MTO
BOM lists all the components for the construction and fabrication of an item. Piping BOM is used as a reference for the warehouse to give the material to the fabricator. Whereas, MTO lists all items for purchase or procurement. It is a reference for material cost calculation.
Difference between BOM and BOQ
BOM provides a material list for component fabrication and is used at the site during construction. Whereas, BOQ is a tendering document prepared at an early stage of the project. BOQ provides a basic scope of work based on drawings and specifications.
In terms of dollar value, the oil and gas industry is considered the best global powerhouse that employs thousands of workers worldwide and controls the overall energy market. Professionals working or aspiring to work in the oil and gas industry should be aware of the oil and gas industry overview. They must know the working cycle of the industry and the responsibilities of the different sectors involved in the process. This article will provide a brief introduction to the oil and gas industry and the key points related to it.
Oil and Gas Industry Overview
The oil and gas industry is one of the largest industrial sectors in the world in terms of generating value in dollars. This is also known as the petroleum industry. This industry is very crucial to the global economic framework, especially for countries like the United States, Saudi Arabia, Russia, Canada, and China. Petroleum is important to many industries and is necessary for the operation and maintenance of Industrial plants, machines, and transportation purposes.
Brief History of Petroleum
Petroleum is a naturally occurring liquid found in rock formations. It consists of a mixture of hydrocarbons of various molecular weights, plus other organic compounds. It is widely known and accepted that oil is generated from the carbon-rich remains of ancient plankton after exposure to pressure and heat in Earth’s crust over hundreds of years.
Fig. 1: Contribution of the different companies to the oil and gas industry
Different Sectors of the Oil and Gas Industry
The Oil and Gas Industry or petroleum industry has been divided into the following three sectors-
Upstream oil and gas
Midstream oil and gas
Downstream oil and gas
Fig. 2: Different sectors of the oil and gas industry
Upstream Oil and Gas Industry
The Upstream Oil and Gas Industry consists of companies involved in the exploration, extraction, and separation of oil and gas. These companies are also known as the E&P (exploration and production) industry. These are the companies that find the place of exploration and set up the plant with the coordination of the local government, and start exploring. If the oil is found beneath the earth then the extraction/production of oil starts otherwise the company will move to the next place for exploration and later on, the separation takes place. This is done either onshore or offshore.
The upstream oil and gas companies are characterized by high risks, high investment capital, and extended duration as it takes time to locate, document procedures, and drill.
What do you mean by exploration, extraction, and separation?
Exploration
Exploration can be defined as a means to provide the required information to exploit the best opportunities presented in the choice of areas and to manage research operations on the acquired blocks, which also involve statutory activity.
An oil company may work for many years on a proposed area before an exploration well is prepared and during this period the geological history of the area is studied. Indeed, exploration is a risky activity and the management of exploration assets and associated operations is a major task for oil companies.
Extraction/Production
The extraction of petroleum is the process by which usable petroleum is drawn out from beneath the earth’s surface location through the well.
Separation
Liquid hydrocarbons/Oil extracted from the wells are separated from the non-saleable components such as water and solid residuals. Natural gases are often processed onsite while oil is piped to a processing unit for separation.
What do you mean by onshore and offshore?
The meaning of the term Offshore is the islands in the open sea belonging to a country. The setup installed in the ocean on the floating platform for the extraction of the oil is called offshore.
Onshore means the setup installed on dry land for oil extraction /drilling/production. Onshore drilling accounts for 70 % of the total oil production.
Fig. 3: Offshore
Fig. 4: Onshore
Midstream Oil and Gas Industry
Midstream Oil and Gas Industry includes those companies that are focused on transportation and storage. They are responsible for moving the extracted raw materials from upstream industries to refineries to process the oil and gas. Midstream oil and gas companies are characterized by shipping, trucking, pipeline fleets, and storing raw materials. The midstream oil and gas sector is also marked by high regulation, particularly on pipeline transmission, and low capital risk. This sector is also naturally dependent on the success of upstream oil and gas companies.
Key Points of Midstream Oil and Gas
Midstream oil and gas refers to the stage in the oil production process that falls between upstream and downstream.
Midstream Oil and gas includes key activities like storage and transportation of Crude Oil.
They are specialized in storage and fleet management.
Downstream Oil and Gas Industry
The Downstream Oil and Gas Industry are those which is responsible for processing, transporting, marketing, and selling refined products made from crude oil. It is dependent upon upstream and midstream oil and gas sectors. Thousands of products to end-user/ customers around the globe are provided by the downstream oil and gas industry. Many products are familiar such as gasoline, diesel, jet fuel, kerosene, heating oil, and asphalt for roads, etc.
Key Points of the Downstream Oil and Gas Industry
Downstream oil and gas operations are the processes that deal with converting Crude oil into finished products.
Companies that handle operations in the downstream oil and gas sector are closest to the customers.
An over-production of crude oil in the upstream section may benefit the downstream oil and gas companies.
Products from Oil and Gas Industry
After extracting the crude oil from beneath the Earth, it is refined and different parts are separated into usable petroleum products. The majority of these products include
gasoline
jet fuel
diesel fuel and heating oil
petroleum feedstocks
lubricating oils
waxes
asphalt, etc.
Fuel oil and gasoline or petrol are the largest volume products from the oil and gas industry. The above-mentioned products are directly obtained from the oil and gas industry. But if we consider the by-products from the oil and gas or petroleum industry then there will be thousands of products. The majority of the items we use in our daily life has some connection to the petroleum industry. To give a few examples all the following products have a link to the oil and gas industry:
Natural Gas
Clothing (acrylic, rayon, vegan leather, polyester, nylon, and spandex) and Shoes
Cleansers
Electronics like speakers, smartphones, computers, cameras, televisions, etc
Sports Equipment (basketballs, golf balls and bags, football helmets, surfboards, skis, tennis rackets, and fishing rods)
Health and beauty products (perfume, hair dye, cosmetics (lipstick, makeup, foundation, eyeshadow, mascara, eyeliner), hand lotion, toothpaste, soap, shaving cream, deodorant, combs, shampoo, eyeglasses, and contact lenses.)
Household items like paints, pillows, non-stick pans, detergents, etc.
Top Oil and Gas Companies of the World
In this world, there are more than 200 oil and gas companies that operate in various countries. However, there are only a few key players in the oil and gas industry market that control the overall oil and gas market of the world. The following list contains 25 such big oil and gas industry market leaders.
China Petroleum & Chemical Corporation or Sinopec, China– $424bn (As per 2020 estimates)
China National Petroleum Corporation (CNPC), China – $396bn
PetroChina, China – $360bn
Royal Dutch Shell, Netherlands – $345bn
Saudi Arabian Oil (Saudi-Aramco), Saudi Arabia – $330bn
BP, UK – $278bn
Exxon Mobil, US – $265bn
Total, France – $200bn
Chevron Corporation, USA – $146.5bn
Rosneft Oil Corporation, Russia – $140bn
Other big Oil and Gas companies are:
Valero, US
Gazprom, Russia
Phillips 66, US
Kuwait Petroleum Corporation, Kuwait
Lukoil, Russia
Eni, Italy
Pemex, Mexico
National Iranian Oil Co (NIOC), Iran
JX Holdings, Japan
Marathon Petroleum, US
Petrobas, Brazil
Equinor, Norway
PTT, Thailand
Indian Oil Corporation, India
Reliance Industries, India
Future of Oil and Gas or Petroleum Industry
The research done by Deloitte shows that more than 14% of permanent employees were laid off in the US in the year 2020 with no recovery. The same trend of layoff is continuing in the year 2021 as well. At the same time, COVID-19 is increasing significantly in all countries impacting the economy throughout. So, What will be the future of the Oil and Gas or Petroleum sector post-COVID scenario?
Experts believe the same downturn of the oil and gas industry will continue to increase as it will face challenges from the following:
The reduced cost of Electric Vehicles due to innovation and batteries is a huge threat to the petroleum industry.
Natural gas power plants are threatened by the clean energy portfolios of wind, solar, and battery storage energies.
Ongoing research on green hydrogen is also a major threat.
Climate policies are canceling major oil and gas industry expansions.
All these new technologies and climate policies are providing a green signal to renewable energy companies. So, the future of the oil and gas industry is not that promising.
Turbine Piping: Definition, Working Philosophy, Layout Consideration, Stress Analysis, NEMA SM 23
In this article, we will explain the Stress Analysis steps after a brief discussion about turbine piping layout considerations. Piping Stress Analysis Software Caesar II is used for the analysis of Turbine Piping.
Turbine Definition
A Turbine is rotating equipment where the kinetic energy of the moving fluid is converted into mechanical energy by rotating a bladed rotor. Turbines are used as mechanical drivers for other machines (for example, compressors) in the refinery, chemical, or petrochemical industry. Turbines may be of various types as mentioned below:
Steam and Gas Turbines basically work on either Impulse or Reaction philosophy.
Impulse turbines change the direction of the flow of a high-velocity fluid or a gas jet. The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. There is no pressure change of the fluid or the gas in the turbine rotor blades, all the pressure drop takes place in the stationary blades (the nozzles)
Reaction Turbines develop torque by reacting to the gas or fluid’s pressure or mass. The pressure of the gas or fluid changes as it passes through the turbine rotor blades. A casement is needed to contain the working fluid as it acts on the turbine stage(s), or the turbine must be fully immersed in the fluid flow.
Layout Considerations for Turbine Piping
Enough flexibility in steam turbine piping has to be provided to make up for thermal stresses as these lines are subjected to high temperatures by providing long-run pipes, expansion loops, and bends.
Line routing should be fabricated by bending or welding processes instead of flange connections to avoid flange leakage in steam lines.
All main area piping has to be done by a vendor.
Steam traps are to be provided in all steam lines to avoid condensate accumulation.
All gas turbine piping vents are to be provided in a high, open, and safe area.
Expansion bellows can be used in large-diameter and short-span, rigid piping systems. (Generally mounted between turbine outlet nozzles and condenser)
All supporting is to be done while keeping the friction at a minimum, for this hanger supports (not recommended for very high vertical displacements) and Teflon pads can be used.
It’s preferable to follow ½ or 1⁄3 times of normal support span for turbine piping.
Variable spring supports with lower variability should be used. As load variability is not taken care of by Caesar so it is the analyst’s responsibility to keep it as low as possible to avoid the transfer of reaction forces and moments due to variable loads to the nozzle connection.
Spring with a larger variable load is allowed if its spring stiffness is low as in the case of constant springs. Bottom-mounted F-type springs should not be used generally to avoid friction if used Teflon pad should be provided.
Caesar II Simulation and Stress Analysis Procedure for Turbine Piping
There are two types of procedures that can be followed for Turbine modeling.
When Nozzle movements/displacements are provided by the vendor:
In most cases, the turbine nozzle movements are provided by the vendor in the datasheet or GA drawing. With that, Caesar’s modeling becomes very easy. The nozzle displacements provided by the vendor are entered at the nozzle connection points (flange points) to the equipment with a C-Node, the rest of the piping has to be modeled as per the normal procedure. However, remember to consider the proper direction of those displacements while entering Caesar II Input Spreadsheet.
When Nozzle movements/displacements are not provided by the vendor:
When nozzle displacements are not provided, the modeling has to be done as per the GA drawing of the equipment provided by the vendor. All detailed drawings and support details with dimensions should be seen clearly to avoid any modeling errors.
The main anchor block of the equipment assembly is the point from where the machine is supported rigidly.
The modeling procedure is explained in this section with an illustrative example for proper understanding.
The Caesar dump (Fig. 1) attached below shows how the modeling is done for the turbine with the inlet and exhaust nozzle attached. Here we will correlate the Caesar dump with the Equipment GA drawing to simulate the configuration.
Fig. 1: Turbine Modelingin Caesar II
Steps for modeling the Turbine
Model elements 10 to 20 as piping flange as per isometric (south direction) with piping design and operating parameters.
Place an anchor on node 10 with C node as 1.
Model nozzle flange from 1 to 3000 taking Temperature and pressure parameters of the turbine.
From 3000 to 3010, model rigid element (length=305 mm from Fig 2, 3 & 4) taking Temperature and pressure parameters of the turbine.
Fig. 2: Sample Turbine GA Drawing
Fig. 3: Part of Sample GA Drawing
Fig. 4: Turbine GA Drawing
From the 3010 to 3020 model the elevation difference of the exhaust nozzle with the inlet nozzle as 20 mm in a vertically upwards direction (see Fig 2 and 3).
Model element from 3020 to 3050 towards the west (see Fig 4 for dimensions (538.2 mm)).
Model 3050 to 3060 up to the inlet nozzle towards the south (For dimensions (478 mm) see Fig 2).
From the 3020 model a rigid element, length= 148.5 mm in the east direction to 3100 (Fig 3).
From the 3100 to 3040 model a vertically downward element length =177.8 mm (See Fig 3). At 3040 place an anchor point. (This point is the location from where the turbine assembly is rigidly supported).
All the Turbines can be modeled in this manner by following the GA drawing. There are certain difficult drawing arrangements that require many data to get a clear idea of how equipment is placed. For this purpose, all detailed drawings should be kept ready to avoid any modeling errors.
Analysis & Output Phase
While modeling the nozzle with displacement (when the vendor provides displacement), the movements D1 (Displacement in operating condition) and D2 (Displacement in sustained condition) have to be added to the operating (W+P1+T1+D1) and sustained load case (W+P1+D2) respectively.
The rest of the load cases corresponding to occasional loads such as wind and seismic has to be prepared as usual.
The main and most important part of the analysis phase is nozzle load checking. NEMA SM23 (For turbines) provides guidelines and equations which help in cross-verifying the external moments and loadings on a nozzle. Nozzles for turbines are to be checked for individual loading as well as combined loading.
In the thermal analysis and nozzle load evaluation, the X-axis of the piping (As per Caesar) should coincide with the Compressor (Turbine) shaft axis direction.
Besides Caesar II also provides modules for NEMA SM23 in the database by which nozzle loads can be directly checked with the help of software in an easy manner.
Nozzle Load Checking per NEMA SM-23
For all rotating equipment following three types of nozzle load checking are performed
A. Individual Turbine Nozzle Checking
The total resultant force and total resultant moment imposed on the turbine at any nozzle connection should not exceed the values given below −
Fig. 5: NEMA Equation for individual nozzle load checking
B. Combined Turbine Nozzle load Checking
The combined resultants of loads and moments of the inlet, extraction, and exhaust connection resolved at the centerline of the largest connection (mainly exhaust nozzle) should not exceed the following −
Fig. 6: NEMA Equation for combined nozzle load checking
C. Individual Component Load Checking
The individual component forces of each nozzle should not exceed the following
Fig. 7: NEMA Equation for individual component checking
Caesar II NEMA SM 23 Module
Caesar II provides an inbuilt NEMA SM-23 module to digitally check turbine nozzle loads and extract the report. The steps for using the module are shown in Fig. 8.
Fig. 8: NEMA SM-23 Module of Caesar II
Few Important points for Steam Turbine Piping Stress Analysis
Ensure the correct Weight of the Valve, flange, and any in-line items, and mark the weight in the stress sketch.
Branch piping (like drip legs etc.) greater than 2 inches should be included in the analysis.
Check Insulation density carefully.
Wherever spring supports are used, define spring rate and cold load.
Alignment or WNC check with springs in the locked and unlocked condition is mandatory for turbine (compressor) piping systems.
Few companies require to perform the hot-cold check for turbines. In that case, From the steam header to the first block valve, consider the same as the line temperature and From the block Valve to the turbine nozzle, consider ambient temperature (not working) and check the nozzle loads as per the code allowable.
