design considerations lecture 2
DESCRIPTION
DesignTRANSCRIPT
General Design Consideration
Plant Location1. 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
Raw Materials Availability The source of raw materials is the most
important factors Near location of the raw-materials source
permits considerable reduction in: Transportation Storage charges
If requirement of large volumes of raw materials, so attention should be given to: Purchased price of the raw materials Distance from the source of supply Transportation expenses Availability and reliability of supply Purity of the raw materials Storage requirements
The location of markets affects:Cost of product distributionTime required for shipping
Markets is an important consideration in the selection of a plant site:Advantageous to buyer
Markets are needed for by-products as well
Markets
High requirements of power and steam in industries
Fuel required to supply power and steam
For Example: Electrolytic processes require a cheap source
of electricity so; Location must be near by large hydroelectric
installations
Plant requires large quantities of coal or oil Location near a source of fuel
Local cost of power can help to determine whether: Power should be purchased or self-generated
Energy Availability
If the plant is located in a cold climate, costs may be increased: Construction of protective shelters around the
equipment If the plant is located in hot climate:
Special cooling towers Air-conditioning equipment may be required
If there is excessive humidity or extremes of hot or cold weather: Serious effect on the economic operation of a
plant Climate factors must be examined when
selecting a plant site
Climate
Transportation Facilities Rail tracks, roads, and highways are the common Products and raw materials required transportation facilities. Possibility of canal, river, lake, or ocean transport must be
considered. If possible, the plant site should have access to all three types of
transportation or at least two types should be available. Water Road Rail
Air transportation facilities between the plant and the main company headquarters
Water Supply The process industries use large quantities of water for;
Cooling Washing Steam generation Raw material.
Plant, must be located, where, water is available River or lake is preferable Deep wells are satisfactory if the amount of water required is not too
high Try to drill several standby wells Factors considered during choosing water supply:
Temperature Mineral content Sand content Bacteriological content Cost for supply Purification
Waste Disposal Legal restrictions have been placed on the methods for
disposing of waste materials from the process industries Site selected for a plant should have capacity and
facilities for correct waste disposal. Attention should be given to potential requirements for
additional waste-treatment facilities
Labor Supply Labor availability must be examined
Consideration should be given to:
Pay scales
Restrictions on number of hours worked per week
Competing other industries
Productivity of the workers
Welfare of workers
Avoid
Taxation & Legal Restrictions State and local tax rates:
Property income
Unemployment insurance
Local regulations on: Building codes
Transportation facilities
Required permits
.
Flood and Fire Protection Many industrial plants are located along rivers and there are risks of flood
Before selecting a plant site:
Regional history of natural events of this type should be examined
Protection from losses by fire is another important factor
In case of a major fire, assistance from outside fire departments should be
available
Community Factors Character and facilities of a community can have quite effect on the
location of the plant
Cultural facilities of the community are important to sound growth
Masjids, libraries, schools, colleges, theaters and other similar
groups, are important for recreation
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Plant Layout After the process flow diagrams and before detailed PID
must planned: Layout of process units in a plant Equipment within these process units
Plant layout play an important part in determining: Construction and manufacturing costs
There is no one ideal plant layout, so several problems may arise
Attention to the storage space and operating equipment Consideration of the safe operational sequence Primary layout based on the flow of materials Three dimensional models
Model of Plant Layout
Plant Operation and ControlInstrumentation
Instruments are used in the chemical industry to measure process variables, Temperature Pressure Density Viscosity Specific heat Conductivity pH Humidity Dew point Liquid level Flow rate Chemical composition Moisture content..
Automatic control is the normal throughout the chemical industry Control is achieved through the use of high-speed computers Control room is used for the indication, recording, and regulation of the
process variables
Panel boards present a graphical representation of the process and have the instrument controls and indicators
Helps to operator To quickly become familiar with instrument readings To rapid location identification of any problem
Instrumentation
Maintenance Many of the problems of maintenance are caused by a lack of original
design and layout of plant and equipment There should be sufficient space for maintenance work on equipment and
facilities.
Utilities Power can be transmitted in various forms such as:
Mechanical energy Electrical energy Heat energy Pressure energy.
The engineer should recognize the different methods and chose best one Decision must be made on whether to use purchased power or have the
plant set up its own power unit Sources of water (Own or Muncipal)
Storage Storage facilities are essential for:
Raw materials Intermediate products Final products Recycle materials Off-grade materials Fuels
Liquids is generally handled by closed spherical or cylindrical tanks. Vapor pressure, an important criterion.
Gases are stored at atmospheric pressure in wet or dry seal gas holders
Solid products and raw materials are either stored in weather-tight tanks with sloping floors or in outdoor bins and mounds
Liquids and gases are handled by means of pumps and blowers, pipes, ducts and in containers such as drums, cylinders.
Solids may be handled by conveyors, bucket elevators, lift trucks, and pneumatic systems.
Factors that must be considered in selecting equipment include:
1. Chemical and physical nature of material being handled
2. Type and distance of movement of material
3. Quantity of material moved per unit time
4. Continuous or batch nature of materials handling Materials-handling problems are:
Corrosion Fire Heat damage Explosion Pollution Toxicity
Material Handling
22
He (Allah) Who produces fire for you out of the green tree so now you kindle fire with the same!
(Al-Quran, Surah Ya-Sin, Verse 80)