Ch2-General Design Considerations UTAS Fall22.pdf

General Design Considerations

1. ENCH4119- PLANT
DESIGN AND ECONOMICS
Instructor:
Name : Dr. Saravana Kumar
Room No : B112
Email: [email protected]

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3. General Design
Considerations
Chapter-2
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The development of a complete plant design requires consideration of many
different factors such as:

a.Plant location
b.Site and plant layout
c.Plant operation and control
d.Utilities
e.Storage
f.Waste disposal
g.Health and safety
h.Ethics
i.Materials handling

5. a. PLANT LOCATION
The geographical location of the final plant can have strong influence on the success of an industrial
venture. Considerable care must be exercised in selecting the plant site, and many different factors must
be considered. Primarily, the plant should be located where the minimum cost of production and
distribution can be obtained, but other factors, such as room for expansion and safe living conditions for
plant operation as well as the surrounding community, are also important.
The following factors should be considered in selecting a plant site
1. Raw materials availability
2.Markets
3.Energy availability
4.Climate
5. Transportation facilities
6. Water supply
7. Waste disposal
8. Labor supply
9. Taxation and legal restrictions
10. Site characteristics
11. Flood and fire protection .
12. Community factors
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b. Site Layout And Plant Layout
Site layout includes
1.Storage for raw materials and products: tank farms and warehouses;
2.Maintenance workshops;
3.Stores, for maintenance and operating supplies;
4. Laboratories for process quality control;
5. Fire stations and other emergency services;
6. Utilities;
7. Effluent disposal plant: waste water treatment, solid and or liquid
waste collection;
8. Offices for general administration;
9. Canteens and other amenity buildings, such as medical centers
10.Parking lots.

7. Selection of the Plant Site
The major factors in the
selection of most plant sites are
(1) raw materials,
(2) markets,
(3) energy supply,
(4) climate,
(5) transportation
facilities,
(6) water supply
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a. Adequate ventilation;
b. Adequate lighting;
c. Adequate heating;
d. Adequate drainage;
e. Dehumidification equipment, if necessary;
f. Accessibility of equipment for operation,
servicing, and removal;
g. Flexibility of operation;
h. Operator safety;
i. Convenience of operation;
j. Chemical storage and feed equipment in a
separate room to reduce hazards and dust
problems;

8. PLANT LAYOUT
After the process flow diagrams are completed and before detailed piping, structural, and electrical design
can begin, the layout of process units in a plant and the equipment within these process units must be
planned. This layout can play an important part in determining construction and manufacturing costs, and
thus must be planned carefully with attention being given to future problems that may arise.
•New site development or addition to previously
developed site
•Type and quantity of products to be produced
•Type of process and product control
•Operational convenience and accessibility
•Economic distribution of utilities and services
•Type of buildings and building-code requirements
•Health and safety considerations
•Waste-disposal requirements
•Auxiliary equipment
•Space available and space required
•Roads and railroads
•Possible future expansion
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10. Preparation of the Layout
Scale drawings, complete with elevation indications can be used for
determining the best location for equipment and facilities. Elementary
layouts are developed first. These show the fundamental relationships
between storage space and operating equipment. The next step requires
consideration of the safe operational sequence and gives a primary layout
based on the flow of materials, unit operations, storage, and future
expansion.
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C .Plant operation and control
In the design of an industrial plant, the methods which
will be used for plant operation and control help
determine many of the design variables. For example,
the extent of instrumentation can be a factor in
choosing the type of process and setting the labor
requirements
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d. Utilities
The word utility is used for the ancillary services needed in
the operation of any production process. These services are
normally supplied from a central site facility and include
1.Electricity;
2.Steam, for process heating;
3.Cooling water;
4.Water for general use;
5.Demineralized water;
6.Refrigeration;
7.Compressed air;
8.Inert - gas supplies;

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e. Storage
Storage facilities are required for:
1.Raw materials
2.Intermediate products
3.Final products
4.Recycle materials
5.Off-grade materials
6.Fuels

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f. Waste Disposal
Waste disposal is a serious problem for many chemical
plants.
Materials produced by the process that cannot be recycled
or sold as by-products must be disposed of as waste.
In some cases additional treatment is required to
concentrate the waste stream before sending it to final
disposal.

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g. Health and safety
Before proceeding any further with the development of a process design and
its associated economics, it will be desirable to consider an overall view of the
various functions involved in a complete plant design. Particular emphasis in
this discussion will be placed on important health, safety, loss prevention, and
environmental considerations. Other items that will be noted briefly include
plant location, plant layout, plant operation and control, utilities, structural
design, storage, materials handling, patents, and legal restrictions.

16. HEALTH AND SAFETY HAZARDS
The potential health hazard to an individual by a material used in any chemical
process is a function of the inherent toxicity of the material and the frequency and
duration of exposure.
short-term and long-term effects
The inherent toxicity of a material is measured by tests on animals. The short-term effect is
expressed as LD
50, the lethal dose at which 50 percent of the test animals do not survive.
long-term exposure of humans to toxic materials is set by the threshold limit value
(TLV).
Recommended TLV values are published in bulletins by the Occupational Safety and Health Agency
(OSHA), the American Conference of Governmental Industrial Hygienists (ACGIH), the American
Industrial Hygiene Association (ARIA), the National Institute for Occupational Safety and Health
(NIOSH), and the United kingdom earth and Safety Executive (HSE).
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any source of potential damage

17. Sources of Exposure
For example, mechanical abrasions of solid materials by cutting, grinding, or
drilling can produce small particles which can form an airborne dust cloud or
solid aerosol. Liquid aerosols, on the other hand, may be produced by any
process that supplies sufficient energy to overcome the surface tension of the
liquid. This process occurs intentionally in spray coating and unintentionally
when oil mist is generated from lubricants or coolants used on
high-speed machinery.
Liquid aerosols can also be produced by condensation.
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•Flammable materials
•Contaminant vapors are normally formed by allowing the liquid to evaporate
into the air.
•Liquid aerosols may be produced by any process.
•Pumps and valves are probably the major source.
•Flammable materials
•Fugitive Emissions
•Solids handling can provide considerable exposure to contaminants whenever
the operation is performed in an open atmosphere.
•Maintenance of any closed system can pose a hazardous exposure problem.
•Spilled materials can become airborne and pose an inhalation hazard.
Sources of Exposure

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Abrasive Blasting
Aerosols
Anthrax
Antineoplastic Agents
Asphalt Fumes
Bicycle Saddles and Reproductive Health
Carbonless Copy Paper
Climate Change
Cold Stress
Decompression Sickness
Electric and Magnetic Fields (EMF)
Exposome and Exposomics
Hazardous Drug Exposures in Healthcare
Heat Stress
Insects and Scorpions
Poisonous Plants
Silica
Ultraviolet Radiation
Venomous Snakes
Venomous Spiders

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24. Exposure-Hazard Types
CHEMICAL & DUST
HAZARDS
(cleaning products, pesticides, asbestos,
etc.)
BIOLOGICAL HAZARDS
(mold, insects/pests, communicable
diseases, etc.)
ERGONOMIC HAZARDS
(repetition, lifting, awkward postures,
etc.)
WORK ORGANIZATION
HAZARDS
Things that cause STRESS!
SAFETY HAZARDS
(slips, trips and falls, faulty equipment,
etc.)
PHYSICAL HAZARDS
(noise, temperature extremes,
radiation, etc.)
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25. Fire and Explosion Hazards
•For a fire to occur, there must be a fuel, an oxidizer and an
ignition source.

•The minimum concentration of fuel in air required for ignition at
ambient temperature is known as the Lower Flammable Limit
(LFL).

•The concentration above which ignition will not occur is labeled
the Upper Flammable Limit (UFL).

•The concentration of oxidizer that must be present for ignition is
called the Limiting Oxygen Index (LOI).

26. Fire and Explosion Hazards

•The temperature at which ignition will occur without the
presence of a spark or flame is designated the Auto ignition
Temperature (AIT).

•The liquid temperature at which the concentration of the fuel
in the air becomes large enough to ignite is labeled the Flash
Point.

27. Fire Explosion – key reasons
•Fire mostly occurred in storage areas
•Fire mostly occurred in unattended areas or
during unattended periods
•Not much importance is paid to fire protection in
storage areas
•Inadequate training for fire emergencies
•No attempt to learn from past mistakes
Lack of
awareness of
safety and
following safety
norms
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28. Fire Triangle
•Most are familiar with the Fire
Triangle.
•In order for a fire to start or be
sustained you need to have a
Fuel, an oxidizer and an ignition
source.
•If one of the three components
is eliminated, then there will
not be a fire (or explosion)
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29. Corrosive Explosive Oxidising Extremely
flammable
Highly
flammable
Very toxic Toxic Harmful Irritant Danger to
environment
CHIP symbols from http://www.opsi.gov.uk/si/si1994/Uksi_19943247_en_4.htm#end
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30. Personnel Safety CONTROLS: PPE
Personal Protective Equipment
Control of LAST RESORT!

Special Clothing

Eye Protection

Hearing Protection

Respiratory Protection
CONTROL IS AT THE WORKER!
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31. Hierarchy of Controls
Requires a physical
change to the workplace
Requires worker
to wear
something
Elimination/Substitution
Requires worker or
employer to do
something
Most Effective
Least Effective
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•Systematic technique to IDENTIFY potential HAZard and OPerating problems
•A formal systematic rigorous examination to the process and engineering facets(aspects)
of a production facility
•A qualitative technique based on “guide-words” to help provoke thoughts about the way
deviations from the intended operating conditions can lead to hazardous situations or
operability problems
•HAZOP is basically for safety
- Hazards are the main concern
- Operability problems degrade plant performance (product quality, production rate, profit)
•Considerable engineering insight is required - engineers working independently could
develop different results
What is HAZOP? HAZard OPerability Analysis

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•It emphasizes upon the operating integrity of a system, thereby leading
methodically to most potential and detectable deviations which could
conceivably arise in the course of normal operating routine
- including "start-up " and "shut-down" procedures
- as well as steady-state operations.
•It is important to remember at all times that HAZOP is an identifying
technique and not intended as a means of solving problems nor is the
method intended to be used solely as an undisciplined means of searching
for hazardous scenarios.
Purpose of HAZOP

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i. Ethics

38. j. materials handling…….
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