Chemical Engineering January 2015 - 53

Feature Report
Engineering Practice
Plot Plan Design:
Process Requirements
It is important to conceptualize plant layout in terms of both ideal location and
optimal geographical positioning of equipment components
Mohammad Toghraei
Engrowth Training
F
or any chemical process facility,
the cost of improper or sub-obtimal
plant layout can be enormous.
Designers are generally
well aware of safety constraints, but
there is often less recognition about
other process requirements that
will impact the design. This article
discusses key elements of plant layout
and plot plan design, in two important
levels:
* Level 1. Plant location. This step
involves selecting the best location
*
Level 2. Plant layout. This step
involves the placement of units
and equipment relative to each
other, in an effort to optimize all
safety, operations and maintenance
objectives
Each requires a certain chain of decision
making that can impact the
success of all efforts (Figure 1).
An integrated effort
Level 1. During Level 1, engineers
seek to identify the optimal location
for the plant. Generally speaking, a
chemical process industries (CPI)
plant should be in a location that
allows it to easily receive raw materials
and have access to utilities,
such as water and power. Other key
considerations are related to access
to the infrastructure needed, such
as roads, rail lines and shipping options,
to enable both the shipment
of products (and side-products) and
the disposal of waste streams.
Other than material resources,
any CPI facility also needs access to
a good supply of human resources.
When plants are established in desirable
locations, they have access
to a broad pool of qualified, skilled
people for operation, maintenance
and management of the plant.
Plant location should also be selected
to minimize the potential
environmental impact of plant operations.
For instance, establishing
a plant in an area that is surrounded
by mountains is often not
a good decision, due to potentially
poor air-flow characteristics in the
area. Similarly, if the treated wastewater
of a plant needs to be injected
into a disposal well, the plant cannot
be very far from an area that
has a suitable underground geological
structure.
Economic parameters are also
important when scouting possible
plant locations. Ideally, stakeholdAREA
1: Production tank farm
Plot plan
AREA 2: Separation area
Product
tank
Product
tank
Separator
Separator
Separator
ers want to locate plants in locations
with minimum land costs and
minimum applicable taxes.
Level 2. During Level 2 efforts,
stakeholders work to identify the
best method for laying out the different
units within the facility. One
overarching objective of a plot plan
(but not necessarily the most important
one) is to minimize the length
of equipment-connecting elements,
such as pipes that convey liquids,
gases and bulk solids. Material
conveying systems, such as screw
conveyors, belt conveyors, also fall
within this category.
During the development and design
of a plot plan, requirements
and limitations are identified and
decisions are made with regard to
the following considerations:
* Process requirements, such as
the need to support equipment
Heat exchangers
O2 Scavenger
AREA 3: Reaction area
Acid
Ion exchange beds
Catalyst
beds
Caustic
Finger pipe racks
Sand Filters
Future
Future
Pipe racks
Neutralization
Raw water Flush water
tank
Future
Thickener
Feed tank
BFW tank
Feed tank
Thickener
AREA 4: Tank Farm
Figure 1. Shown here is a typical plot plan
52 ChemiCal engineering www.Chemengonline.Com January 2015
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Chemical Engineering January 2015

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