Chemical Engineering Plant Design

Lecture 02

Dr. Zakir Khan

Assistant Professor

zkhan@ciitlahore.edu.pk

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

FFC CLUB

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)