Diagramación P&Id

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Process Diagrams
OBJECTIVES
After studying this chapter, the student will be able to:
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•
•
•
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Review process diagram symbols.
Describe the use of process diagrams and the information they contain.
Draw a process flow diagram.
Draw a process and instrument drawing.
Describe the various process equipmentrelationships.

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Chapter 12

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Process Diagrams

Key Terms
Electrical drawings—symbols and diagrams that depict an electrical process.
Elevation drawings—a graphical representation that shows the location of process equipment in
relation to existing structures and ground level.
Equipment location drawings—show the exact floorplan for location of equipment in relation to
the plan’s physical boundaries.
Flow diagram—a simplified sketch that uses symbols to identify instruments and vessels and to
describe the primary flow path through a unit.
Foundation drawings—concrete, wire mesh, and steel specifications that identify width, depth,
and thickness of footings, support beams, and foundation.
Legends—a document usedto define symbols, abbreviations, prefixes, and specialized equipment.
Process and instrument drawing (P&ID)—a complex diagram that uses process symbols to
describe a process unit; also called piping and instrumentation drawing.

Types of Process Diagrams
Process diagrams can be broken down into two major categories: process
flow diagrams (PFDs) and process and instrument drawings (P&IDs),sometimes called piping and instrumentation drawings. A flow diagram is a
simple illustration that uses process symbols to describe the primary flow
path through a unit. A process flow diagram provides a quick snapshot of
the operating unit. Flow diagrams include all primary equipment and flows.
A technician can use this document to trace the primary flow of chemicals
through the unit. Secondary orminor flows are not included. Complex control loops and instrumentation are not included. The flow diagram is used
for visitor information and new employee training.
A process and instrument drawing is more complex. The P&ID includes a
graphic representation of the equipment, piping, and instrumentation. Modern process control can be clearly inserted into the drawing to provide a
processtechnician with a complete picture of electronic and instrument
systems. Process operators can look at their process and see how the engineering department has automated the unit. Pressure, temperature, flow,
and level control loops are all included on the unit P&ID.

Basic Instrument Symbols
Process technicians use P&IDs to identify all of the equipment, instruments, and piping found in their units.New technicians use these drawings

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Basic Instrument Symbols

VALVES
S
Gate
Valve

Needle

Globe
Valve

Four-Way

Diaphragm

Angle

Manual
Operated Gauge
Valve

H

Solenoid
Valve
CLOSED

Hydraulic

Back
Pressure
Regulator

Back
Pressure
Regulator

Pneumatic
Operated

Three-Way
ValveButterfly

M

Ball

Bleeder
Valves

Plug

Check Valve

Orifice

COMPRESSORS

Reciprocating
Compressor

Pneumatic
Operated
Butterfly Valve

Motor

Rotameter

Relief
PRV

Safety
PSV

PUMPS & TURBINE

Vacuum
Pump

Centrifugal
Pumps

Centrifugal
Compressor

Compressor &
Silencers

Vertical

T
Liquid Ring
Compressor

Rotary
Compressor

ScrewPump

Centrifugal Compressor
(Turbine Driven)

Turbine

Gear Pump

HEAT EXCHANGERS

LINE SYMBOLS
Future Equipment
Major Process

Hairpin Exchanger

U-Tube
Heat Exchanger

Shell & Tube Heat Exchanger

Minor Process
Pneumatic
Hydraulic
Capillary Tubing

Single Pass
Heat Exchanger

Reboiler

LLL
X X XXX

X

Electromagnetic Signal
Heater

Condenser

Electric...