Piping dan Instrumentation Diagram (P&ID)merupakan skema
dari ,jalur pipa,equipment, instrumentasi, control system,dari
suatu sistem proses yang terdapat diOil Refinery,Chemical Plant,
Paper Mill, Cement Plant, dll. Simbol-simbol yang terdapat dalam
P&ID mewakili peralatan seperti actuator, sensor-sensor dan
kontroler. P&ID menjelaskan secara detail mengenaiflow
process(Diagram Alir), terkecuali parameter-parameter seperti
temperatur, tekanan, dan besarnya arus tidak dapat dijelaskan dalam
P&ID. Alat-alat process sepertivalve(katup), instrument,dan
Saluran pipa diidentifikasikan dengan kode. Kode-kode tersebut
berdasarkan ukuran, jenis cairan yang dialirkan, jenis sambungan
pipa (Seperti dengan menggunakanBoltatauFlang), dan keadaan
StatusValve(Normally CloseatauNormally Open).
Diagram P&ID pada suatu Process SystemP&ID dapat
digambarkan dengan tangan (gambar biasa diatas kertas) atau dengan
menggunakan komputer.Softwaredalam membuat P&ID untuk PC atau
Mac, antara lain dapat menggunakan Microsoft Visio (PC), Omni
Grafle (Mac), atau menggunakansoftwareyang didesain untuk P&ID
yaitu Cadworx P&ID dari COADEBeberapasoftwareP&ID ini tidak
menunjukan ukuran aktual dan posisi dari peralatan-peralatan
seperti sensor,valve,danequipment,akan tetapi untuk menampilkan
sebuah diagram hubungan dari suatu sistem process yang disimpan
sebagai data elektronik dan dapat dilihat di PC.SoftwareCadworx
P&ID dapat menyimpanDatabasedan menghasilkanReportequipment
table listdari komponen-komponen / instrument yang terdapat dalam
P&ID suatu process. Pada bagian berikutnya dari artikel ini
kita akan membuat suatu P&ID dengan menggunakansoftwareCadworx
P&IDRepresentasi dariLine ProcesspadaP&IDLine
SymbolLineSymboldigunakan untuk menggambarkan hubungan antara
unit-unit yang berbeda dalam sistem yang dikontrol. Tabel berikut
di bawah ini merupakan Line Simbol yang pada umumnya sering
digunakan.Tabel 1.Line SymbolDari table 1,Piping linemerupakan
proses utama dimana pipa mengalirkan bahan kimia yang
diidentifikasikan dengan menggunakan kode. Simbol linelainnya
menjelaskan bagaimanasystemterhubung antara satu proses dengan
proses lainnya,serta signal yang digunakan dalam sistem
instrumentasi, sepertielectrical signal,pneumatic signal,data,
dll.
Gambar 1Kode-kode yang terdapat padaPiping Linemenunjukan
Diameter Pipa,FluidService, material, dan isolasi.Diameter pipa
dalam Inch.Fluid servicememberi keterangan jenis fluida yang
dialirkan. Materialmemberikan informasi mengenai bahan pembuat
pipa. Sebagai contoh CS untukCarbon Steelataustainless
steelSS.Pengunaan kode-kode pada Process Line sebagai contoh gambar
1, pada aliran pipa no 39 menunjukan pipa dengan diameter 4 Inch,
dengan Fluid Service mengalirkan bahan kimia N, berbahan material
CS (Carbon Steel) , dan tanpa insulasi (No Insulation)
Simbol untuk Valves
Simbol untukValves ActuatorSimbol untuk Fitting dan
Representasi
Simbol untuk EquipmentInstrumentation SymbolKode-kode
Instrumentasi yang tertera di P&ID adalah sebagai berikut,
huruf pertama mengidentifikasikan parameter yang dikontrol, huruf
selanjutnya mengidentifikasikan tipe perangkat control
Berdasarkan contoh diagram P&ID di atas,FT101, huruf pertama
F mempunyai arti kode (berdasarkan kode ISA) yaituFlow. Huruf kedua
T mempunyai artiTransmitter,kode FT101 dapat diartikan sebagaiFlow
Transmitter,Lingkaran menunjukan FT101terpasang(mounted)diField
Area,yang dihubungkan olehelectric signal(Garis putus-putus). Pada
FIC101, berarti (Flow Indicator Controller), simbol berupa kotak
dan lingkaran menunjukanFIC101, terletak diShared Control / Shared
Displaysdan dapat diakses oleh operator
Huruf PertamaParameter yang dikontrol
AAnalysis
CConductivity
DDensity
EVoltage
FFlow Rate
ICurrent
LLevel
MMoisture(Humidity)
PPressure or Vacuum
TTemperature
VViscosity
Huruf SelanjutnyaTipe Peralatan Kontrol
AAlarm
CController
IIndicator
TTransmitter
VControl Valve
EElement
ICIndicator Controller
FCRatio Controller
RRecorder
HSHand Switch
HVHand Valve
QTotalizer
IQIndicating Totalizer
XVSolenoid Valve
YCalculation
FYRatio Callculation
SLSwitch Low
SHSwitch High
ALAlarm Low
ALLAlarm Low Low
AHAlarm High
AHHAlarm High High
Process and Instrumentation Symbols - EquipmentsPumps and tanks
come in a variety of designs and shapes.
Pumpsis a mechanical device using suction or pressure to raise
or move liquids, compress gases, or force air into inflatable
objects such as tires. The symbols for pumps may closely resemble
those for compressors.Centrifugal pumpis rotodynamic pump that use
a revolving impeller to add to the force and pressure of
fluids.Gear pumpprovide continuous, non-pulsing flow making it
ideal in chemical installations.Sump pumpis widely used to remove
accumulated water from a sump pit or other location.Vacuum pumpis
used to improve the efficiency of steam heating systems in many
ways. The most important consideration is the rapid and efficient
removal.Screw pumpis the Archimedes screw pump that is still used
in irrigation and agricultural applications.Tankis used to store
process fluids of various types, under different process
conditions.Onion tankis an open top collapsible bladder designed
for use as a mobile storage solution when recovering
contaminants.Compressoris a mechanical device that takes in a
medium and compresses it to a smaller volume. A mechanical or
electrical drive is typically connected to a pump that is used to
compress the medium.Axial compressoris widely used in gas turbines,
such as jet engines, high speed ship engines, and small scale power
stations.Reciprocation compressoris typically used where high
compression ratios are required per stage without high flow rates,
and the process fluid is relatively dry.
Rotary compressoris a type of gas compressor which uses a rotary
type positive displacement mechanism.Mixingis a device that combine
or put together to form one substance or mass.Mixing vesselis a
container that is used to blend several components together.Heat
exchangeris a device used to transfer heat energy between two
process flows. Heat exchangers transfer heat energy through
conductive and convective heat transfer.Cooling towerstransfer heat
energy to the outside air through the principle of
evaporation.Cooleris a device, container or room that cools air
through the evaporation of water or keeps cool.Turbine driver is
used to drive pumps and fans at petrochemical plants.Furnaceis a
device for heating a continuous current of air by means of a fire
contained within the apparatus and without mingling the fresh air
with the products of combustion.Boileris a closed vessel in which
water or other fluid is heated.
Oil burnerlis engineered from the ground up exclusively to burn
waste oils.Automatic stokers used to supply hot water to central
heating systems.Plate toweris used widely in many processes and
industrial applications.Packed toweris a type of packed bed used to
perform separation processes.Elevatoris used to control the
position of the nose of the aircraft and the angle of attack of the
wing.Mixing reactoris widely used in the chemical industry to
promote mixing.Process and Instrumentation Symbols - Valves
Gate valveis a device used to control the flow of liquids and
gases.Check valve, also known as one-way valve, is to prevent the
line of medium back.Globe valveis a mechanism used to control or
stop the flow of liquid or gas through a pipe.Ball valveis a valve
with a spherical disc, the part of the valve which controls the
flow through it.Butterfly valveis installed between two flanges
using a separate set of bolts for each flange.Angle valveis
oriented at an angle 90 deg of gate valve.Process and
Instrumentation Symbols - Piping LinesProcess flow diagrams use
special piping lines to represent how signals are transmitted
between equipments. These symbols are used to identify how the
instruments in the process connect to each other. And what type of
signal is being used. (electrical, pneumatic, data, etc)
All lines to be fine in relation to process piping lines.Major
pipelineis used to connect the equipment in any position.Major
Straight lineis sued to connect the equipment in the same
horizontal or Vertical position.Process connectionhelp create the
process flow between equipments. Double click process connection to
edit description.
Process and Instrumentation Symbols - InstrumentsProcess Flow
Diagram use symbols and circles to represent each instrument and
how they are inter-connected in the process.
These instrumentation symbols can easily change types by
clicking the quick action button while designing.