Sistem
Perpipaan
Perancangan Alat Proses Abdul Wahid Surhim
Piping Fundamentals PIPING SYSTEM • • • • • • • • • • •
What is that? Concept Layout Development Piping Components & their access requirement. Straight length requirements. Orientation of various tapings, components, etc. Piping Drains & Vents Insulation. Material & Sizing Critical piping system consideration. Pipe Stress Analysis. Pipe Supports
Rujukan • Noname. Piping Basics (PPS Form) • Raswari. 1987. Sistem Perpipaan. UI Press • Escoe, A. Keith. 2006. Piping and Pipeline Assessment Guide. Elsevier Inc. All rights reserved • Ellenberger, J. Phillip. 2014. Piping and Pipeline Calculations Manual. Second Edition. Elsevier Inc. All rights reserved • Devki Energy Consultancy Pvt. Ltd. 2006. BEST
PRACTICE MANUAL: FLUID PIPING SYSTEMS
Piping Fundamentals • Let us first Discuss about WHAT IS PIPE! • It is a Tubular item made of metal, plastic, glass etc. meant for conveying Liquid, Gas or any thing that flows. • It is a very important component for any industrial plant. And it’s engineering plays a major part in overall engineering of a Plant. • In next few pages we shall try to familiarize about pipe and it’s components.
Piping dan Pipeline • PIPING: in-plant piping ~ inside a plant facility – process piping, – utility piping, etc
• PIPELINE: a long pipe running over distances transporting liquids or gases – often extend into process facilities
In any plant various fluids flow through pipes from one end to other. Now let us start with a plant where we see three tanks. Tank-1, Tank-2 and Tank-3 We have to transfer the content of Tank no. 1 to the other two tanks.
We will need to connect pipes to transfer the fluids from Tank-1 to Tank-2 and Tank-3
LET US BRING THE PIPES.
To solve these problems we need the pipe components, which are called
We have just brought the pipes, now we need to solve some more problems.
Pipes are all straight pieces.
PIPE FITTINGS
We need some branch connections
We need some bend connections
These are the pipe fittings, There are various types of fittings for various purposes, some common types are Elbows/Bends, Tees/Branches, Reducers/Expanders, Couplings, Olets, etc.
Anyway, the pipes and fittings are in place, but the ends are yet to be joined with the Tank nozzles.
We now have to complete the end connections. These, in piping term, we call
TERMINAL CONNECTIONS.
So far this is a nice arrangement. But there is no control over the flow from Tank-1 to other tanks. We need some arrangement to stop the flow if needed
These are flanged joints This is a welded joint
To control the flow in a pipe line we need to fit a special component. That is called - VALVE
There are many types of valves, categorized based on their construction and functionality, Those are - Gate, Globe, Check, Butterfly, etc.
Other than valves another important line component of pipe line is a filter, which cleans out derbies from the flowing fluid. This is called a STRAINER
Valve (Katup) 1. 2. 3. 4. 5. 6. 7.
Butterfly valve Globe valve Gate valve Ball valve Check valve Diaphragm valve Knife Gate valve
8. Plug valve 9. Spool Valve 10.Pressure Relief Valve 11.Pressure Safety Valve (PSV) 12.Control valve
Here we see a more or less functional piping system, with valves and strainer installed. Let us now investigate some aspects of pipe flexibility.
If this tank nozzle expands, when the tank is hot.
In such case we need to fit a flexible pipe component at that location, which is called an
EXPANSION JOINT
When some fluid is flowing in a pipe we may also like know the parameters like, pressure, temperature, flow rate etc. of the fluid.
Expansion Joint Manufacturers Association (EJMA)
To know these information we need to install INSTRUMENTS in the pipeline.
Next we shall look into how to SUPPORT the pipe/and it’s components.
There are various types instruments to measure various parameters. Also there are specific criteria for installation of various pipe line instruments.
Here are some of the pipe supporting arrangements. There can be numerous variants. All depend on piping designer’s preference and judgement.
Let us see some OTHER types of supports
• We have just completed a pipe line design. • We shall rewind and check how it is really done in practice. First the flow scheme is planned, 1) What, 2) From what point, 3) To which point Pipe sizes are selected, pipe material and pipe wall thickness are selected. Types of Valves are planned
Also the types of instruments required are planned • We represent the whole thing in a drawing which is called Piping and Instrumentation Drawing, in short P&ID. For P&ID generation we use SPP&ID software. • By this time you have already come to know that while we prepare P&IDs in SPP&ID, we enter all the pipe lines system information in the drawing. • So the SPP&ID drawing is an Intelligent drawing which under it’s surface carries all the information about a pipe like, Pipe size, Flowing Fluid, etc. • Let us see a P&ID prepared in SPP&ID
This is screen picture of P&ID made by SPP&ID If we click on any line it will show the Data embedded.
After the P&ID is ready we start the layout work. Here we carryout pipe routing / layout in Virtual 3D environment. We use PDS 3D software to route piping in the Plant virtual 3D space. We call this as piping modeling or physical design. While development of piping layout we have to consider the following
Piping from source to destination should be as short as possible with minimum change in direction. Should not hinder any normal passage way. Also should not encroach any equipment maintenance space.
Not Preferable Preferable
While carrying out pipe routing we also need to consider the following Valves, strainers, instruments on the pipe should be easily accessible. If needed separate ACCESS PLATFORMS to be provided to facilitate these.
Desired location and orientation of valves / instruments and other pipe components are to be checked and maintained, like some valves or strainers can only be installed in horizontal position. Specific requirements for instrument installation to be checked, like temperature gauge can not be installed in pipe which is less than 4 inch in size. Specific requirements of STRAIGHT LENGTH of pipe for some components to be maintained, like for flow orifice we need to provide 15 times diameter straight pipe length at upstream of orifice and 5 times diameter straight at down stream of orifice.
Example of Straight length requirement for Flow Orifice
For Pipeline which shall carry liquid, we have to make sure that all air is allowed to vent out of the line when the line is filled with liquid. To achieve this a VENT connection with Valve is provided at the top most point of the pipeline. Also arrangement is kept in the pipeline so that liquid can be drained out if required. To achieve this a DRAIN connection with Valve is provided at the lowest point of the pipeline Pipes are also slopped towards low points. Let us look into typical Vent and Drain arrangement in a pipeline
This is a 3D model of Feed water line along with pumps and other accessories
Let us have a look into a piping model done by PDS 3D
INSULATION - When hot fluid flows through pipe then generally pipe is insulated. There are two primary reasons for insulating the pipe carrying hot fluid. Containing the heat inside the pipe. Insulation preserves the heat of the fluid. It is called Hot Insulation Personnel safety, so that people do not get burn injury by touching hot surface of pipe. It is called Personnel Protection Insulation Cold pipes are also insulated Cold or chilled fluid carrying pipes are insulated to prevent heating of cold fluid from outside. It is called Cold Insulation.
Some times cold pipes are insulated to prevent condensation of atmospheric water vapor on pipe surface. It is called Anti-Sweat Insulation. Other types of Insulation When gas flows through pipes at high velocity, it creates noise. In such cases pipes are insulated to reduce noise. It is called Acoustic Insulation. Some times pipe and it’s content are heated from outside, by heat tracing element. In that case pipe along with heat tracing element are insulated to conserve the heat of the tracer. It is called Heat Tracing Insulation.
INSULATION MATERIAL - The insulating material should be bad conductor of heat. There are two basic categories 1) Fibrous Material, which has large voids full of air between fibers - Cork, Glass Wool, Mineral Wool, Organic Fibers. Note stagnant air is a bad conductor. 2) Cellular Material, which has closed void cells full or air - Calcium Silicate, Cellular Glass (Foam Glass), Polyurethane Foam (PUF), Polystyrene (Thermocol), etc. Some times Cast material like Cement Plaster or Plaster of Paris are also used. INSULATION CLADDING - Insulation materials are generally soft or fragile. So the outer surface of insulation are protected with Aluminum sheet or GI sheet cladding. Have a look at how pipes are insulated, and general components of insulation
H h. A.Th Ta H = Heat loss, Watts h = Heat transfer coefficient, W/m2-K Ta= Average ambient temperature, K Th = Hot surface temperature (for hot fluid piping), ºC & cold surface temperature for cold fluids piping) For horizontal pipes: h A 0.005Th Ta For vertical pipes:
h B 0.009Th Ta
r1 t k Etk r1 t k ln r1 Etk = Equivalent thickness of insulation for pipe k = Thermal conductivity of insulation at mean temperature of Tm, W/m-C tk= Thickness of insulation, mm r1= Actual outer radius of pipe, mm r2= (r1+ tk) Ts= Desired/actual insulation surface temperature, ºC Rs= Surface thermal resistance = 1/h, ºC-m2/W Rl= Thermal resistance of insulation = tk/k, ºC-m2/W
Th Ta Th Ta Th Ta 1 H Rl Rs Rl Rs H H h tk Rl t k Rl .k k
Th Ts Tm 2
PIPE MATERIAL SELECTION - to select appropriate pipe material based on flowing fluid property. Find out type of Fluid flowing
Find out Fluid Temp. & Pressure
Check Pipe life Expectancy
Select suitable Material per practice (Note-1)
Check Mat. Listed in Design Code
YES
Pipe Material OK
NO
Note-1 : Material is selected per past experience with cost in mind and per material listed in design code. If material is not listed in code we may select next suitable material listed.
See Note-1
PIPE SIZING CALCULATION - to select required pipe diameter based on velocity and pressure drop. Find out Flow volume per second
Check Velocity Allowable per second
Calc. flow area required and Pipe size
Calc. Press. Drop for that Pipe size
Check Press. Drop meets Press. Budget
YES
Pipe Size OK
NO Increase Pipe Size
\ PIPE THICKNESS SELECTION - to select appropriate pipe thickness based on flowing fluid property. Select Mat. & Diameter as above
Find out Fluid Temp. & Pressure
Decide on Corrosion allowance
Calc. Pipe Thickness per Code
Batasan Operasi • Ada dua batasan untuk penentuan DIAMETER PIPA: 1. Kecepatan gas 10 – 60 fps (umumnya, rinciannya lihat API RP 14E) 2. Jatuh tekanan
Penentuan Kecepatan Gas MAKSIMUM • Penentuan DIAMETER PIPA sangat dipengaruhi oleh KECEPATAN GAS • Batas maksimum kecepatan gas: kecepatan yang menyebabkan terjadinya erosi pada pipa atau disebut EROSIONAL VELOCITY (ve) menggunakan API RP 14E untuk layanan kontinyu:
ve
100
G0.5
• Erosi pipa terjadi jika kecepatan gas melebihi ve • Kecepatan gas yang direkomendasikan: 40 – 50% dari ve (Mohitpouret al., 2002)
Kecepatan Minimum • Jika mungkin, kecepatan minimum pada jaringan dua fasa (gas-cair): 10 fps • Tujuan: meminimisasi pembentukan lumpur pada peralatan separasi • Hal ini penting khususnya pada jaringan pipa panjang dengan perubahan ketinggian (API RP 14E hlm. 23)
Contoh • Berikut ini adalah data-data bagian pipa dari sebuah jaringan pipa transmisi gas: Q = 25.7 MMSCFD, Ta = 90 oF, P1 = 425 psia, P = 9 psia, L = 8280 ft, SG = 0.7, Za = 0.925, MWudara = 28.96, R = 10.731, E = 1.0, viskositas gas diabaikan. a) b)
Pa
Hitung tekanan rata-rata (Pa) menggunakan rumus Campbell: Pilihlah diameter pipa yang sesuai menggunakan rumus Panhandle A: T 403.09 E P P D P s
Q
c)
d)
P1 P2 2 P1 P2 3 P1 P2
SG
2 1
2 0.5 2
2.619
Ta Z a L 0.5397G 0.0793 s
0.4603
Hitung erosional velocity (ve)—sebagai batas maksimum kecepatan gas melalui pipa— menggunakan persamaan API RP 14E untuk layanan kontinyu: ve = 100/(G)0.5 (ingat rumus PaVG=nRTaZa) P T Qa Q s a Pa Ts
Hitung kecepatan gas (vG) menggunakan laju alir aktual: Apakah diameter pipa yang didapatkan memenuhi kriteria ve > vG?
Z a
Jawaban Q Ta P1 DP P2 L SG Za MWudara R E
Pa Ts Ps D MWgas rho G
ve Qa vG
25.7MMSCFD 25700000CFD 90oF 550.67oR 425psia 9psia 416psia 8280ft 1.568182mil 0.7 0.925 28.96 10.731 1
420.5psia 15oC 1atm 11.847inch 20.272 = massa G/Vol G = Pa.Mwgas/(RTZ) 1.560lb/cft 80.1fps 880589.2574cfd =4Qa/(pi.D^2) 13.1fps
59oF 519.67oR 14.7psia ==> PILIH NPS 12 SCH 40 ID
10.19201cfs < ve
OK
11.938INCH
Kode dan Standar Pipa (US) 1. ASME B31.1, Power Piping ~ governs piping in the power industries (e.g., power plants). 2. ASME B31.2, Fuel Gas Piping. 3. ASME B31.3, Chemical Plant and Petroleum Refinery Piping ~ governs piping systems used in the chemical and petroleum industry. 4. ASME B31.4, Liquid Petroleum Transportation Piping Systems ~ governs liquid hydrocarbons and other liquids in pipeline systems. 5. ASME B31.5, Refrigeration Piping and Heat Exchanger Components. 6. ASME B31.7, Nuclear Piping was withdrawn after two editions and the respon-sibility was assumed by ASME B&PV Code, Section III, Subsections NA, NB, NC, and ND
Kode dan Standar Pipa (US) 7. ASME B31.8, Gas Transmission and Distribution Systems ~ governs gas pipelines. 8. ASME B31.8S, Managing System Integrity of Gas Pipelines is a recently published book 9. ASME B31.9, Building Services Piping. 10.ASME B31.11, Slurry Piping Systems is another transportation pipeline code that mostly applies to buried piping systems that transport slurries 11.ASME B31.12, Hydrogen Piping System—this is a new code. It is in the final stages of first development
BIAYA SISTEM PERPIPAAN 1. 2. 3. 4. 5. 6. 7.
Bahan Fittings Installation labor Installation equipment Supports P&G Others
30% 10% 25% 10% 10% 10% 5%
Miranda & Lopez, 2011. “Piping Design: The Fundamentals”. Presented at “Short Course on Geothermal Drilling, Resource Development and Power Plants”, organized by UNU-GTP and LaGeo, in Santa Tecla, El Salvador, January 16-22, 2011.
In Power plant there are some piping which carries steam at high pressure and temperature. And also there are piping which carries water at High pressure. These pipes carries the main cycle steam and water of the steam power plant. These pipelines are call the CRITICAL PIPING.
Very special care are taken for design of these piping. First the pipe material selection for such piping is very important as it has to withstand the high pressure and may be also high temperature. As these pipes carry the main system fluid of the power plant, they are given the right of way, and routed at beginning of the overall plant layout. Steam pipes run at very high temperature and the hot pipes expand. We have to built in flexibility in the high temperature pipe routing so that the expansion force is absorbed within the piping. Also there should be enough flexibility in these pipe routing so that high loads are not transferred to the nozzles of Turbine or Pumps There are many recognized international codes which lay down guide lines and mandatory requirements for design of such piping. The most important codes used by power plant piping engineers are ASME ANSI B31.1- Power Piping Code & IBR - the Indian Boiler Regulation
Pipe Stress Analysis We have already seen that some of the pipes are subjected to high pressure and high temperature. Also pipes carry the load of the flowing fluid. We need to check and confirm the pipe is not going to fail with these loading.
This process of checking the stress developed in the piping due to various loading is called Pipe Stress Analysis/Flexibility analysis. In the process of Analysis we apply various postulated loading on the pipe and find out the stress resulted from these loading.
Then we check with governing codes if those stresses generated are acceptable or not. We check support load & movement for various loading condition. We also check out the terminal point loading generated from pipe to the equipment connected to the pipe. This loading are to be within acceptable limits of the equipment suggested by the vendors. We also find out the pipe growth due to change in temperature and need to keep the movement of pipe within acceptable limits. Pipe Stress Analysis is an Interactive and Iterative process. Each step is checked If a check fails we have to go back, modify the layout and restart the analysis.
PIPE STRESS ANALYSIS Inputs
Tools we use
Geometric layout of Pipe
PIPSYS - is an integrated pipe stress analysis module of PLADES 2000
Pipe supporting configuration Pipe Diameter and Thickness Pressure inside Pipe Cold and Hot temperatures of Pipe Weight of Pipe and insulation Weight of carrying Fluid Pipe material Property (Young’s Modulus, Thermal Expansion Coefficient) Thrust on pipe due to blowing wind. Thrust on pipe due to earthquake Load of Snow on pipe Any transient loading like Steam Hammer load Any other load on the piping
CEASER - Commercial Piping analysis software There are many other commercial software available
Outputs Stress of the pipe at various loading conditions Load at various supports and restrains. Movement of pipe at support locations Pipe terminal point loading.
Codes and Standards In general Power Plant Piping have to comply stipulations of ASME ANSI B31.1 In India Power cycle Piping to comply IBR code requirements.
Types of Pipe Supports In the beginning of this discussion we talked about various types of pipe supports. Here is some elaboration
Constant Load Spring
There are three general types Rigid type (no flexibility in the direction of restrain)
Variable Spring
There are two types of spring support Variable load type, here support load changes as the pipe moves. Constant load support, the load remains constant within some range of movement.
Rigid Support
Dynamic Support (Degree of restrain depends on acceleration of load)
Rigid Hanger
Spring type (Allows pipe movement in direction of loading)
Dynamic Support, Snubber Rigid Support
Some Special Considerations for Piping When pipes are routed UNDER GROUND (Buried) following points to be kept in mind: Minimum pipe size to be routed under ground shall be not less than1 inch. Avoid flange joint in U/G piping. Keep in mind if pipe leaks U/G, it will be difficult to detect, so avoid U/G routing of pipe carrying hazardous fluid. Pipe to be laid below Frost Zone at areas where ambient temperature goes below freezing.
U/G, Buried piping should be properly protected from corrosion. Pipe may be properly wrapped and coated to prevent corrosion. Or U/G piping be protected by using Cathodic protection. Freeze Protection of outdoor Piping:
In the areas where the ambient temperature goes below freezing there is a possibility that the liquid content of pipe may freeze while the plant is under shut down. For similar case pipes are wrapped with heat tracing elements to maintain the content temperature above freezing (around 4 deg. C) even when the ambient temp. is below freezing. Electric Heat tracing is done by wrapping electric coil around pipe, which turns on as the ambient temperature goes down. Pipes are insulated over the heat tracing coils. Heat tracing can also be done by winding Steam tubes around main pipes.
Jenis Pipa 1. Pipa tanpa sambungan (tanpa sambungan pengelasan) 2. Pipa denga sambungan
Bahan Pipa (Umum) 1. 2. 3. 4. 5. 6. 7.
Carbon steel Carbon moly Galvanees Ferro nikel Stainless steel PVC Chromen moly
Bahan Pipa (Khusus) 1. 2. 3. 4. 5. 6. 7.
Viber glass Alumunium Wrought iron (besi tanpa tempa) Copper (tembaga) Red brass (kuningan merah) Nickel copper = monel (timah tembaga) Nickel chrome iron = inconel (tembaga timah krom)
Jenis-jenis Pipa: Berdasarkan MATERIALnya 1. Pipa logam – – – – –
Pipa besi tuang Ductile cost iron pipe (DCIP) Galvanized iron pipe (GIP) Cast iron pipe (CIP) Pipa logam campuran (metal/alloy)
Jenis-jenis Pipa: Berdasarkan MATERIALnya 2. Pipa non logam – Pipa beton (tanpa tulangan, dengan tulangan) – Pipa PVC (poly vinyl chloride) – Pipa fiber glass (GRP = Glass fiber reinforced pipe) – Pipa asbes semen – Pipa PE (poly ethylene)
Jenis-jenis Pipa: Berdasarkan Bentuk Melintangnya
•
Pipa bulat → ○ Digunakan untuk air minum
•
Pipa bulat telur (elips) → 0 Digunakan untuk air buangan
Jenis-jenis Pipa: Berdasarkan Bentuk Ujungnya • •
•
•
Flanged end pipe (pipa ujung flens) Terbuat dari baja dan memiliki diameter yang besar. Bell and plain pipe (pipa ujung bell dan spigot) Biasanya jenis PVC (poly vinyl chloride) atau DCIP (ductile cost iron pipe). Screwed end pipe (pipa ujung ulir) Biasanya jenis GIP (galvanized iron pipe) dan memiliki diameter yang kecil. Double plain end pipe (pipa ujung rata) – – –
Ujung rata biasa Ujung rata dengan lidah Ujung rata dengan takikan
Seamless Drawing Steel Pipe
Electric Resistence Welded Steel Pipe
Seamless Brown Pipe Lap Welded Steel Pipe
Pipa dari Timah Hitam Pipa Galvanis
Pemilihan Bahan Pipa • Sesuai standar ASTM dan ANSI 1. Perpipaan untuk pembangkit tenaga 2. Perpipaan untuk industri bahan gas 3. Perpipaan untuk penyulingan minyak mentah 4. Perpipaan untuk pengangkutan minyak 5. Perpipaan untuk proses pendinginan 6. Perpipaan untuk tenaga nuklir 7. Perpipaan untuk transmisi dan distribusi gas
Tipe Sambungan Cabang • Sambungan langsung (stub in) • Sambungan dengan menggunakan fittings • Sambungan dengan menggunakan flanges
Diameter Pipa • Terdapat tiga istilah diameter untuk pipa bulat: – Inside diameter (ID) – Outside diameter (OD) – Nominal diameter (ND)
• Dalam standar ISO, ukuran pipa dinyatakan dalam satuan millimeter (mm) • Nominal diameter (ND) digunakan dalam istilah perdagangan atau sebagai petunjuk spesifikasi pipa • Dimensional standards, materials of construction, and pressure ratings of pipiing for chemical plants and petroleum refineries are covered by ANSI Piping Code B31.3 which is published by the ASME, latest issue 1980.
Diameter, Ketebalan dan Schedule • Schedule pipa dikelompokkan menjadi 1. Schedule : 5, 10, 20, 30, 40, 60, 80, 100, 120, 160 2. Schedule standar 3. Schedule extra strong (XS) 4. Schedule double extra strong (XXS) 5. Schedule spesial
Manfaat Perbedaan Schedule • • • •
Menahan tekanan dalam dari aliran Kekuatan dari meterial itu sendiri Mengatasi karat Mengatasi kegetasan pipa
Ketebalan Dinding Pipa
Ketebalan Dinding Pipa
Pemasangan Pipa • Ada tiga kelompok: 1. Pipa di atas tanah – Pipa kolom dan vessel, HE, pompa dan turbin, kompresor, utilitas
2. Pipa di bawah tanah – Pipa proses dan utilitas
3. Pipa di dalam air
Pipa Transmisi dan Distribusi Gas • Sistem Perpipaan Transmisi – Pipa transmisi adalah pipa yang dipasang dengan tujuan untuk menyalurkan gas dari sebuah sumber suplai gas kepada satu atau lebih pusat distribusi dan konsumen dengan kebutuhan gas yang besar. Pada umumnya, pipa transmisi beroperasi pada tekanan lebih dari 16 bar. Sistem ini biasanya digunakan pada gas/steam power palnt atau industri besar
Pipa Transmisi dan Distribusi Gas • Sistem Perpipaan Distribusi – Pipa distribusi adalah pipa yang dipasang dengan tujuan untuk menyalurkan gas dari sumber suplai gas yang berasal dari pipa transmisi kepada konsumen. Pada sistem distribusi dikenal istilah pipa utama dan pipa sektor. Pipa utama adalah pipa yang digunakan untuk mengantarkan gas ke beberapa konsumen dalam suatu rute. Sedangkan pipa sektor adalah pipa dari percabangan pipa utama yang mengantarkan gas ke alat metering atau peralatan konsumen yang membutuhkan gas tersebut. Diameter pipa yang sering digunakan sebagai pipa utama adalah 40 mm – 180 mm. Sedangkan untuk pipa sektor, pipa yang digunakan berdiameter 13 mm – 20 mm. Pipa dengan diameter yang lebih besar biasanya digunakan untuk keutuhan komersial dan industri
Perbedaan Sistem Perpipaan Transmisi dan Distribusi
Kondisi Standar
Standar Teknis • Standar teknis adalah spesifikasi teknis atau hal-hal yang terkait dengan aspek teknis dalam perancangan dan operasional kegiatan keteknikan yang disusun dan dibakukan berdasarkan konsensus semua pihak terkait dengan mempertimbangkan aspek keamanan, keselamatan, kesehatan, lingkungan, perkembangan ilmu pengetahuan dan teknologi, serta berdasarkan pengalaman, perkembangan masa kini dan masa yang akan datang untuk memperoleh manfaat yang sebesarbesarnya
Standar Teknis 1. 2. 3. 4. 5.
ANSI B 31.8 DNV OS F-101 Pemasangan Pipa Baja Perencanaan dan Pemasangan Pipa PE Standard Lainnya
ANSI B 31.8 • ANSI B 31.8 merupakan standar yang digunakan untuk sistem pipa transmisi dan distribusi gas bumi (Gas Transmission and Distribution Piping System) yang dikeluarkan oleh badan standar nasional Amerika (American National Standards Institute). • Standar ini juga digunakan di Indonesia dan saat ini telah diadopsi menjadi Standar Pertambangan Migas SPM No. 50.54.2, Sistem Perpipaan Transmisi dan Distribusi Gas
DNV OS F-101 • DNV OS F-101 merupakan standar yang digunakan untuk Submarine Pipeline Systems, yang dikeluarkan oleh DNV (Del Norske Verilas), suatu badan sertifikasi dan verifikasi di Norwegia. • Standar ini digunakan untuk perencanaan pipa minyak dan gas serta pipa fluida lain yang melintasi perairan dan laut, baik berupa pipa proses dan pipa transportasi serta struktur bangunan. • Standar ini baru dikeluarkan pada tahun 2000, merupakan pengembangan dari standar DNV 1996, Rules for Submarine Pipeline Systems dan digunakan secara luas oleh perusahaan eksplorasi dan produksi migas di dunia terutama di Laut Utara
Pemasangan Pipa Baja • Pemasangan pipa gas yang menggunakan material baja standar mengacu pada standar SPM 5D.54.0, Pengelasan Saluran Pipa dan Fasilitas yang terkait. • Standar ini diadopsi dari standar API 11.04 dari American
Pipeline Institute
Perencanaan dan Pemasangan Pipa PE • Perencanaan dan pemasangan pipa gas yang menggunakan material plastik polyethylene (PE) mengacu pada standar SNI 13-3507-1994. • Standar ini merupakan hasil adopsi standar Inggris BG/PS/Dis 5.3 Part A & B serta standar SNI 13-35021994
Standar Lain • Standar lain yang merupakan pendukung dan referensi dalam perancangan teknis diantaranya adalah standar pipa (API 51), standar kerangan (API 6D), standar material (ASTM), standar pengujian (ASME) dan lain-lain
Persamaan Aliran Gas 1. Persamaan Panhandle A 2. Persamaan Panhandle B 3. Persamaan Weymouth 4. Persamaan Polyflow 5. Persamaan Poles 6. Persamaan Moody 7. Persamaan AGA 8. Persamaan IGT 9. Persamaan Darcy-Weisbach 10.Persamaan Beggs-Brill 11.Persamaan Eaton
Perhitungan Heat Loss (hf) 2
fLu hf 2 gd
f = faktor friksi dari grafik L = panjang pipa (m) u = kecepatan aliran melalui pipa (m/s) g = gravitasi, 9.81 m/s2 d = diameter dalam pipa (m)
ud Re Re = Reynold number = densitas fluida (kg/m3) d = diameter dalam pipa (m) µ = Dynamic viscosity (Pa s)
Estimation of friction factor
The absolute roughness of pipes
Contoh 2 • Pipa dengan diameter 4” (100 mm) mengalirkan alir dengan laju alir 50 m3/jam sepanjang 100 m. Bahan pipanya cast iron dengan kekasaran absolutnya 0.26 mm • Hitung heat loss-nya
Jawaban Q 50 u 1.77 m/s 2 A 36003.14 0.1 / 4
ud 10001.7 0.1 Re 177000 0.001 absolute roughness k 0.26 Relative roughness 0.0026 internal diameter d 100 Sesuai dengan grafik, maka f = 0.025
fLu 0.0251001.77 hf 4 m per 100 m pipa 2 gd 29.810.1 2
2
Minor Loss Coefficient 2
hmin or loss
ku 2g
Pressure Drop
Tekanan Rata-rata P1 P2 2 Pa P1 P2 3 P1 P2 • P1 tekanan gas masuk pipa • P2 tekanan gas keluar pipa
Pipa PE (Poly-Ethylene) • Ketebalan pipa PE dihitung berdasarkan nilai SDR (Standard Dimension Ratio):
Tekanan Operasi PE 2 MRS MOP SDR 1Hd MOP = Tekanan operasi maksimum atau Maximum Operating Pressure (Mpa) MRS = Minimum Required Strength (Mpa), dapat dilihat dari daftar “physical properties“ dari material PE yang ditawarkan SDR = Standard Dimention Ratio (nominal diameter luar/nominal ketebalan dinding yang dispesifikasikan) Hd = Rasio menahan abrasi pipa PE terhadap pipabaja, nilainya sama dengan 4 (empat)
Simulator Sistem Perpipaan • • • •
Pipesim Pipephase OLGA Pipe Flow Expert
Contoh 3 (PIPESIM) Jaringan A
Jaringan B
Pipe Sizing Rules of Thumb NO Type of LIne
Pressure Drop (psi/100 ft) Average
1 2 3 4 5 6 7
Maximum
Velocity (fps)
Pemodelan Pipa Distribusi dengan PIPESIM Pilih “NEW Network”
Setup: Unit dan Komposisi
Drag: Source, Junction dan Sink
Pipa Percabangan (Branch)
Setup Komposisi
Blok komponen
Klik
Setup SOURCE
Suhu Tekanan Laju alir
Trial 1: Panjang dan ID Pipa
RUN (Harus Disimpan Dulu)
Hasil Simulasi
Terlalu tinggi karena PIPA terlalu KECIL
Trial 2: Diameter Pipa
OK
Trial 3: Panjang Pipa Maksimum • Panjang Maks: 50 km (kecepatan < 60 fps)
Plot Penurunan Tekanan
TUGAS 2 Berdasarkan gambar jaringan pipa gas: 1. Hitung diameter pipa jaringan gas sesuai dengan tekanan operasinya: CS (menengah) 2. Jenis pipa PE dengan SDR berapa yang seharusnya digunakan? Kenapa? 3. Hitung panjang maksimum pipa 4. Hitung kapasitas maksimum pipa
Gunakan ketiga software (Pipesim, Pipeline Toolbox dan Pipe Flow Expert) Data pipa PE dapat menggunakan “hdpe-pipe-specifications”
JARINGAN GAS 700m
Jaringan A P = 2 Barg
Tapping Point (Titik Pasikan Gas) P = 10 Barg F = 3.25 MMSCFD
500m
P = 2 Barg
Tapping Point (Titik Pasikan Gas) P = 6 Barg F = 2.37 MMSCFD
Jaringan B
