Chemical Engineering March 2011 - 57

Project
phase*
Process Safety
Management
(PSM) and
Management of
Change (MOC)
reviews
Piping line list
input
Process activity
Project
phase*
* PSM/HAZOP preliminary
* PSM/HAZOP final
* List of action items
* MOC process set up
* MOC process activities
* Obtain line list from Piping Dept. or develop one
from the P&IDs
* Size primary lines
* Size minor lines
* Update process information on line list
* Internal review of line list
* Update line list (line list is owned by the piping
dept.)
Equipment
design
* Equipment sizing calculations
* Equipment sizing files
* Equipment sizing calculation, internal review
* Equipment sizing, client review
* Sized equipment list
* Metallurgical considerations
* Equipment data sheets, Revision A (this is the
process dept. information issued to the mechanical
dept. for its input)
* Equipment Engineering Design Summary (EDS)
(explains the sources of data used and assumptions
behind the equipment sizing)
* Equipment data sheets, Revision A (client review)
*
Equipment data sheets, Rev. B
* Transmittal to the mechanical dept. for its input
to data sheets
* Update for vendor comments and clarifications
* Process review of the mechanical dept. EDS, Rev.
D, for inquiry and purchase order
Front End
Loading (FEL)
package format
Equipment
design
(cont.)
Process
activity
* Equipment technical bid evaluation
* Process sign-off for purchase order (While this is
not always practiced, it is important for highly
engineered equipment such as towers, compressors,
and so on)
Environmental * Environmental review of process
* Fugitive-emissions estimate
* Flare-emissions estimate
* Pump-seal requirements (per leak detection
and repair, LDAR, requirements)
* Wastewater considerations
* Solid-waste considerations
* Waste stream alternate disposition
* Air and water permit data
Study report
format
* Style (These formats are best saved as company
styles and developed only once)
* Writing
* Assembly
* Transmittal (hard copy and electronic)
* Style
* Writing
* Tables
* Figures
* Assembly
* Internal review
* Revision
* Transmittal (hard copy and electronic)
Front end
engineering
development
(FEED) package
format
* Style
* Writing
* Tables
* Figures
* Assembly
* Internal review
* Revision
* Transmittal (hard copy and electronic)
Archiving
* Archive list
* Archive procedures
* Archiving
In general, a PFD shows the following
details:
* All process piping including major
bypass or recirculation lines
* Flow direction
* A preliminary line size based
on heat and material balance
(H&MB) conditions
* Interconnecting lines to other units
* Major equipment and item
numbers
* Primary control instruments
By comparison, PFDs typically do
not show:
* Pipe specifications or line numbers
* Piping or mechanical specialty items
* Process control instrumentation beyond
the primary element and related
control valve
* Minor process lines
* Vents and drains, double
blocks and bleeds
* Process safety valves (PSVs)
* Other piping and process details of a
minor nature
In general, PFDs typically follow this
familiar format:
* Streams enter at the top left of the
first page and streams leave on the
right side of each sheet
* All equipment components are represented
in sequence and connected
by lines representing the piping
* Major utilities are indicated in
terms of where they are used in
the process
* Lines are called streams and each
one carries a unique number for
reference. A diamond shape is typically
used
* The stream numbers correspond to
the stream summary in the H&MB
in conjunction with the PFD
* A H&MB usually accompanies a
PFD giving the stream composition,
flowrate, physical properties and
thermodynamic properties
* Each equipment item on the PFD
has a unique equipment item number,
and a corresponding equipment
block summarizing such parameters
as dimensions, capacity, horsepower,
material of construction, design
pressure and design temperature
* The equipment symbols identify the
piece of equipment within reason
and are typically understood by all
process engineers
* The PFD has a revision number and
date to indicate its current status
* Normal, minimum and maximum
stream values are given for
defined cases
* Each H&MB represents a " case, "
whether it is normal operation,
start-of-run conditions, end-ofrun
conditions, or a particular
product run
Most, but not all of these characteristics
are usually found on a PFD. A
typical PFD is shown in Figure 2 with
all of these attributes.
Developing the PFD
PFDs can be developed using paper
and a pencil, or they can be developed
using a process simulator. All major
simulators have PFD screens where
the simulation is pieced together in a
PFD format. How a PFD is developed
isn't critical, but using a simulator
can save the engineering team a lot
of time.
A PFD is used to quickly understand
a process, so it makes sense to
minimize the sheets required to define
the process. As a first pass, try to
use a single sheet to show the entire
process. Fifteen to twenty equipment
items can occupy a single sheet. HowCHEMICAL
ENGINEERING WWW.CHE.COM MARCH 2011 47
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Chemical Engineering March 2011

Table of Contents for the Digital Edition of Chemical Engineering March 2011
