Introduction to P&ID Reading & Design
May 11, 2017 | Author: shan4600 | Category: N/A
Short Description
Descripción: drawing...
Description
Introduction to P&ID Reading and Design
Process Engineering
Process engineering is often a synonym of chemical engineering.
It focuses on design, operation and maintenance of chemical and material manufacturing processes.
Process engineering also involves developing new processes, project engineering and Process troubleshooting.
Services in Process Engineering
Process conceptual and feasibility study Process project scope definition Process design, evaluation and modification PFD and P&ID development Process modeling and simulation Process equipment sizing and selection Process safety analysis Process troubleshooting
Applications of Process Engineering
Chemical plants
Biotech plants
Crude oil refineries
Fertilizer production
Oil & gas processing
Food processing
Pharmaceutical manufacturers
Pulp paper mills
Mineral processing
Water treatment plants
Nuclear power plants
......
Type of Flow Diagrams in Process Engineering
Mass Flow Diagram
Block Flow Diagram (BFD) Also known as Information Flow Diagram
Process Flow Diagram (PFD)
Piping and Instrumentation Diagram (P&ID) Also known as Mechanical Flow Diagram (MFD).
Utility Flow Diagram This is a type of P&ID for common plant utilities (steam, utility air, fuel oil, etc.)
An Example of Block Flow Diagram (BFD) Diluent
Diluted Bitumen
NHT CDU
Kerosene
DHT
Diesel
Upgrader Naphtha
LVGO
VDU
Sour Gas
HC
HVGO
SCO
Treating
FG (upgrader)
Naphtha
SDA
DAO
Pitch
EB
SRU
Diesel GO
Sulfur
Gasifier H 2S
GSFR
H2 (upgrader)
Syn Gas
Composed of only blocks (rectangles) and straight lines Each block represents one or more unit operations The lines represent the major process flow streams (material/ energy flows)
Process Flow Diagram (PFD)
A PFD is a schematic representation of a process using symbols to illustrate major operation units and major process flow lines.
A PFD also tabulates process design values for the streams in different operating modes (minimum, normal and maximum).
A PFD is typically the first drawing developed for a process, often in the pre-conceptual or conceptual design phase.
What should be included in a PFD
A PFD should include: Major equipment (symbols, names and identification #) Main process piping and flow direction Operating pressure and temperature Major bypass and recirculation lines Major control and instrumentation (optional) A PFD should not include: Pipe line numbers Minor components and minor bypass lines Isolation and shutoff valves Maintenance vents and drains Relief and safety valves Code class information
A Sample of PFD
Piping & Instrumentation Diagram (P&ID) – Scope
It is a detailed symbolic representation of process interconnection, including all equipment, piping, and instrumentation. All items are identified using a standard numbering system. It should be developed at the Basic Engineering stage. It is the basis for all Detail Engineering work in plant design.
Piping & Instrumentation Diagram (P&ID) – Synonyms
Process and instrument diagram (P&ID) √
Piping and Instrument diagram (P&ID) √
Mechanical flow diagram (MFD)
Engineering flow diagram (EFD)
Piping and wiring diagram (P&WD)
Pipe and identification diagram (P&ID)
Piping & Instrumentation Diagram (P&ID) – Multidisciplinary
Technical contents of P&IDs rely on multidisciplines:
Process Mechanical Piping Control and Instrumentation Plant Operation
P&ID – Classification
Process P&ID
Utility Plant P&ID
Show the distribution of utilities within a given process. Valving and instrumentation on piping are shown for main headers up to and including branch root valves.
Interconnecting (Rack) P&ID
Define utility units such as cooling towers, air compressors, boilers, unit drain collection systems, fire water systems, and water treatment plants.
Utility Distribution P&ID
Define on-plot process unit design, as well as off-plot tankage and shipping systems
They are the connecting link between individual process, utility plant, and utility distribution P&IDs. They are usually prepared for the offsite pipe racks and link the various process and utility plants.
Vendor P&ID
Prepared for systems that support major equipment packages.
Piping & Instrumentation Diagram (P&ID) – Format
There are no universal format to be used in developing P&IDs.
The P&ID formats vary with industry segments and contractors.
In reality, every industrial company that develops or uses P&IDs has its unique formats/guidelines for P&IDs.
The P&ID preparation should follow the formats from individual clients. The P&ID formats are similar for different companies in the same industry.
Two Key Elements in P&IDs
Piping:
Physical elements that interconnect equipment and process flow. In different sizes, normally expressed as nominal sizes In different materials. The most common material is carbon steel. Other metals, such as various grades of stainless steel, and plastic materials, such as PVC, Teflon, are also used. With thermal insulation, if required.
Instrumentation
Devices used to measure, control, and monitor the process variables. These variables can be flowrate, temperature, pressure, liquid level, viscosity, and others. Control valves and relief valves are also an important part of the instrumentation.
Relationship between PFD and P&ID
For a process, a PFD is a simple representation, while a P&ID is a definitive and comprehensive representation. A PFD shows major equipment and major process lines, while a P&ID shows all equipment and all process lines. A PFD shows major operating conditions (flow, temperature and pressure), while a P&ID shows piping, valves and instruments that monitor and control the process. P&IDs are more important in the design process, but PFDs provide a basis for P&IDs development. PFDs and P&IDs use the same symbols and formats.
What should be included in a P&ID?
All equipment with names and identification numbers Piping with flow direction and line numbers (pipe specifications and line sizes are included in line numbers) All valves All instrumentation with controlling devices and signal inputs and outputs Interconnection references (from one P&ID to another P&ID) Miscellaneous – vents, drains, special fittings, sample lines, and reducers Permanent start-up and flush lines Interfaces for class changes Vendor and contractor interfaces Identification of components and subsystems delivered by others Intended physical sequence of the equipment
What should not be included in a P&ID?
Manual switches Equipment rating or capacity Pressure, temperature and flow data Supplier package piping which is internal to the package and has no operational interface Elbows, tees and similar standard pipe fittings Extensive explanatory notes Physical details and dimensions Piping connections and type (e.g. threaded, flanged, etc.)
Basic Steps for P&ID Preparation
Show all equipments with necessary piping to carry out the process Show all connecting process piping necessary to carry out the process Show all other piping required for auxiliaries Show all required valves and major non-standard fittings Show all required instruments and control loops Mark size, fluid code, material code & identification numbers of all pipe lines Mark interlock numbers as per interlock description Review P&ID considering all operational, startup /shutdown, safety, maintenance & aesthetic aspects
Three Key Types of Symbols in P&IDs
Equipment symbols: Process operation units for mass transfer, heat transfer, momentum transfer and chemical reaction
Piping symbols: Relevant to pipe, valves, and connections
Instrumentation symbols: Sensing, monitoring and controlling The symbology follows the ISA standard ANSI/ISA5.1-1984 (R1992).
Equipment Symbols in P&IDs
Pumps Compressors Fans & blowers Mixers & agitators Conveyors & feeders and other material handling Separation equipment (liquid-liquid, liquid-gas, liquid-solid, gas-solid, gas-gas) Tanks & drums (storage) Heat exchangers Heating & cooling elements Reactors Turbines, generators and motors Transportation equipment
Examples of Equipment Symbols
Piping Symbols in P&IDs
Process flow lines (often combined with signal lines for instrumentation) Valves P&ID connectors Reducers/Increasers Caps Connections In-line items Fire and safety Miscellaneous labels
Examples of Piping Symbols
Instrumentation Symbols in P&IDs
General instrument or function symbols Signals and lines Sensors (four basic instrument groups) Temperature (T) Pressure (P) Flowrate (F) Level (L) Self-actuated devices Pressure (regulators, relief/safety valves) Temperature, flow, and level (regulators) Valve actuators Pneumatic & electric (solenoid, diaphragm, cylinder,
motor, etc.)
With & without positioners
Miscellaneous labels
Signal/Line Symbols
Some Sensor & Control Valve Symbols
Exercise: Identification of P&ID Symbols
General Instrument Symbols Instrument Symbol
Instrument Location Solid line: Control room panel No line: Field Double solid: Remote panel Dash line: Behind panel in control room Double dash line: Behind remote panel
A circle -- individual measurement instruments such as transmitters, sensors, and detectors for pressure, temperature, flow, level
A square with a circle inside -instruments that both display measurement readings and perform some control function (e.g. DCS connection and control)
A hexagon -- computer functions.
A square with a diamond -- PLC (Programmable Logic Control) functions.
Instrument Identification – Tag Number
Instrument symbols should contain letters and numbers.
The letters indicate the instrument type, and the numbers identify the control loop.
PI
PI
PI
217
217
217
a
b
c
Usually 2 or 3 letters are used.
Examples of Instrument #
The first letter identifies the measured or initiating variable, The second is a modifier, The remaining letters identify the function.
Normally a plant # should be prefixed to the Tag#.
e.g. 265-PI217 (265 is a plant #)
a. b.
c.
Pressure indicator, Loop 217, located in the field. Pressure indicator, Loop 217, on control panel, located in the control room. Pressure indicator, Loop 217, signal to DCS.
Instrument Identification Letters First Letter Measured or Initiating Variable
Modifier
Succeeding Letters Readout or Passive Function
Output Function
Modifier
User’s Choice
User’s Choice
A
Analysis
Alarm
B
Burner, Combustion
User’s Choice
C
User’s Choice
D
User’s Choice
E
Voltage
F
Flow Rate
G
User’s Choice
H
Hand
I
Current
J
Power
Scan
K
Time
Time Rate of Change
L
Level
M
User’s Choice
N
User’s Choice
User’s Choice
O
User’s Choice
Orifice
P
Pressure, Vacuum
Test Point
Q
Quantity
R
Radiation
S
Speed, Frequency
T
Temperature
U
Multivariable
V
Vibration, mechanical analysis
W
Weight, Force
X
Unclassified
x-axis
Y
Event, State or presence
y-axis
Relay, Compute, Convert
Z
Position, Dimension
z-axis
Driver, Actuator
Control Differential Sensory (Primary) Ratio Glass, Viewing Device High Indicate
Control Station Light
Low
Momentary
Middle User’s Choice
User’s Choice
Integrate, Totalize Record Safety
Switch Transmit Multifunction
Multifunction
Multifunction
Unclassified
Unclassified
Well Unclassified
Some Combinations of Instrument Letters PC
Pressure controller
TA
Temperature alarm
PI
Pressure indicator
TI
Temperature indicator
PT
Pressure transmitter
TR
Temperature recorder
PR
Pressure recorder
TY
Temperature I/P converter
PY
Pressure converter
TW
Temperature well
PIC
Pressure indicating controller
TIC
Temperature indicating controller
PRC
Pressure recording controller
TRC Temperature recording controller
PSV
Pressure safety valve/ Pressure relief valve
TCV
PCV
Pressure control valve
I/P: Current to Pneumatic.
Temperature control valve
Some Combinations of Instrument Letters FA
Flow alarm
LA
Level alarm
FE
Flow element
LAH
Level alarm high
FI
Flow indicator
LAL
Level alarm low
FR
Flow recorder
LC
Level controller
FT
Flow transmitter
LG
Level glass
FY
Flow I/P converter
LI
Level indicator
FF
Flow ratio
LIC
Level indicating controller
FCV
Flow control valve
LRC Level recording controller
FRC
Flow recording controller
LCV
Level control valve
A Control Loop Example in P&ID
FT123: field-mounted flow transmitter FIC123: panel-mounted flow indicating controller located in a shared control/display device TY123: temperature I/P converter located in an inaccessible location TT123: filed-mounted temperature transmitter TIC123: field-mounted temperature indicating controller. Its output is connected via an internal software or data link to the setpoint (SP) of FIC123. YIC123: an event indicating controller. All inputs and outputs are wired to a PLC accessible to the operator. YIC typically indicates a controlled on/off valve.
Rules of Thumb in P&ID Design
P&IDs are typically developed from PFDs, so that understanding the designed process is a key basis for P&ID design.
P&IDs do not have a drawing scale and usually present only the functional relationship, not the relative physical locations of components.
P&IDs are done in a “single line” format that represents all piping and ductwork as a single line regardless of size.
P&IDs should be specific to one system only, i.e. no more than one system should be shown on a single diagram.
P&IDs should be configured such that major flow should generally be from left to right and from top to bottom, if possible. Primary flow paths should not suffer major changes in directions on P&IDs.
P&IDs should start simple and then be enhanced in several revisions to address the real process by various disciplines.
Following the style from the existing P&IDs for the same client.
Line Designation (Line Number) in P&IDs
Line # is required for piping in P&IDs
Position of the line #: normally above piping lines
Different formats of line # for different companies
A line # contains the following basic information:
Plant # Commodity symbol Line serial # Piping/Line size Piping/Line class (optional)
An example: 6N1-4”-CA2B Plant 6, Nitrogen line 1, 4” pipe, piping class – CA2B
Styles for Flow Direction in P&IDs 1.
Flow arrow at each turning point
2.
3.
Flow arrow at the end of each line
Flow arrow at the middle of each line
Valve Status for Bypass Lines
It’s better to mark the valve status on the bypass lines including safety relief lines:
NC – Normal Closed NO – Normal Open CSC – Car Seal Closed CSO – Car Seal Open LC – Lock Closed LO – Lock Open
Relief valves need to indicate their set pressures
e.g. SET @125 PSIG
Accompanying Deliverables from P&IDs
Equipment List
Line List (Line Designation Table - LDT)
Valve List
Instrument List
Tie-In List A Tie-in List shall be issued indicating the extent of the Vendor package battery limits each time a P&ID issue is made starting with IFA. For plant modification, the tie-in point is the point where from process or utility is connected in the existing systems.
“Holds” List A "Holds" list must be issued each time a P&ID issue is made starting with IFD. The "Hold" indicates where the information used as input to the P&ID is preliminary and the item is used with risk in the downstream design.
Revision list A Revision List defines the changes made in the design so that appropriate action can be taken to accommodate those changes. A Revision List must accompany any issue of P&IDs after IFH if the changes are too extensive to be distinguished in the revision box and by clouding. (IFA - Issued for Approval, IFD - Issued for Design, IFH - Issued for HAZOP)
“As-Built” P&IDs
When there are modifications done in construction, commissioning, qualification, or at any other time after the facility has been validated and operating, the P&ID must be modified to indicate the latest information.
Frequently these modifications arise from construction, post-construction, and C&Q walk-downs prior to the system turn-over from IQ, OQ and PQ.
All changes must be processed through the Quality Management System (QMS).
All changes on a P&ID must be bubbled, signed and dated.
Often a new revision number should be assigned to a “AsBuilt” P&ID.
Software for Developing P&IDs
AutoPLANT P&ID – AutoCAD-based (Bentley)
PlantSpace P&ID – MicroStation-based (Bentley)
SmartPlant P&ID – Able to convert AutoCAD or MicroStation based P&ID to SmartPlant P&ID (Intergraph)
CADWorx P&ID – AutoCAD-based (CodeCAD Inc.)
AutoCAD P&ID – AutoCAD-based (Autodesk)
CADPIPE P&ID – AutoCAD-based (AEC Design Group)
AutoFLOW – AutoCAD-based (PROCAD)
HexaCAD P&ID – (Hexagon Software)
AutoCAD P&ID 2007 for Developing P&IDs 1.
Industry standard P&ID symbols
2.
Dynamic process and signal lines
3.
Dynamic components
4.
Report and list generation
5.
Import and export to MS Excel
6.
Tag generation and uniqueness
7.
Search and edit using a spreadsheet interface
8.
Easy symbol creation and substitution
9.
Review and approve data edits http://www.autodesk.com/us/autocadpid/interactiveoverview2008/index.html
View more...
Comments
