UNIT-IIIMATERIALS OF PLANT

CONSTRUCTION

FACTORS AFFECTING SELECTION OF MATERIAL FOR PLANT CONSTRUCTION. Type of factors. 1. Chemical factors 2. Physical factors 3. Economical factors

CHEMICAL FACTORS1. Contamination of the product by material of plant

lead to instability, decomposition and physiological effect.

E.g. presence of traces of heavy metal decompose penicillin.

Stability of vitamins decrease in presence of metallic ions (Cu++, Co++, Ni++).

The color of esters will change to pale yellow in the presence of iron impurities.

Esters should be processed in S.S.

CHEMICAL FACTORS

2.The effect on the material of plant by drugs and chemicals.

Acids, Alkalis and Oxidizing agent and tannins may affect the material of construction.

Allows and Plastic have a corrosion resistant properties.

PHYSICAL FACTORS

1. Adequate Mechanical Strength.2. Erosion3. Weight4. Ease of fabrication5. Thermal Expansion6. Thermal Conductivity7. Cleansing 8. Sterilization9. Transparency

Material of plant construction

Ferrous

Non-Metals

CastIron

SteelCarbon

StainlessSteel

Inorganic

Glass Organic

Non-FerrousMetals

Aluminum Lead

Rubber Plastic

FERROUS METALS Widely used bcz of its mechanical strength,

abundant availability and lower cost. Varieties of iron are 1. Cast Iron 2. Carbon Steel 3. Stainless steel

CAST IRON Cast iron consist of iron with a proportion of carbon

(beyond 1.5 %). The properties of iron depends on the amt of carbon

present. Cast iron is abundantly available, inexpensive.

GRAY CAST IRON

MALLEABLE IRON

HIGH SILICON CAST IRON

NICKEL RESISTANT CAST IRON

CARBON STEEL OR MILD STEELCARBON STEEL IS AN IRON ALLOY, WHICH CONTAINS ONLY A SMALL PERCENTAGE OF CARBON.

Variety of Carbon Composition AdvantagesAllow

STAINLESS STEEL It is an allow of iron. It contains chromium and nickel, which makes the steel

corrosion resistant. S.S. is stabilized by the addition of titanium, or

tantalum. Minor amt of other elements such as copper,

molybdenum, & selenium are added. S.S has the advantages of ease of fabrication.Properties of S.S. 1. Heat resistant 2. Corrosion Resistant 3. Ease of fabrication. 4. Tensile strength 5. Cleaning and Sterilization.

MARTENSITIC

AUSTENITIC

FERRITIC

1.ALUMINIUM It is cheap, light in weight and offer good mechanical strength.

Al. equipment can be easily fabricated.

Al. can be strengthened by cold working.

Number of modifications of Al are available.

Al is non toxic to micro-organism.

2.LEAD It has the lowest cost.Used as collapsible tube material particularly for non-food products such as adhesives, inks, paints and lubricants.

Lead tubes with internal linings are used for fluoride tooth-paste.

Lead chamber process is used in the manufacture of sulphuric acid.

LEAD ALLOYA AND MODIFICATIONS Acid lead and copper leads are used in chemical

industries. Some metals are added to lead for altering

properties. Silver and Copper: Improve corrosion resistant. Improve creep and fatigue resistant. Antimony, Tin, Arsenic: Hardens, steel melting point is low. Lead lined steel structures are used for the

constructions of pipes, valves, vessels designed for operations at high temp, fluctuating temp or vacuum.

1.GLASS

1. GLASS The glass that is prepared by silicon dioxide alone

is the most resistant, but relatively brittle. It can be melted and moulded at high temp. To modify the physicochemical properties cations

such as sodium, potassium, calcium, magnesium, aluminum, boron, iron etc are added.

Glass containers used in pharmaceutical industries are classified in four groups, class I , class ii, class iii, class iv.

Most of the alkali oxides such as Na2O, K2O. Mgo and Cao enter the spaces within the structures and reduce the strength of inter-atomic forces between silicon and oxygen.

1. GLASSThe oxide decrease the melting point

of glass and are comparatively free to migrate.

This behavior cause number of problems like:

Oxides leach in to the solution, raise the pH, hydrolyze or catalyze chemical reactions.

Some times glass flakes are formed in the solution.

Types General Description Properties Uses

2.GLASS STEEL

RUBBERUsed as such as a lining material for the construction of plants.

Type of rubber1. Natural Rubber2. Soft rubber.3. Hard Rubber4. Synthetic Rubber.

SOME VARIETIES OF SYNTHETIC RUBBER.

Five type of Synthetic Rubber1. Neoprene 2. Nitrile Rubber3. Butyl Rubber4. Silicon Rubber5. Polyisoprene

1. NEOPRENE (POLYCHLOROPRENE)

2. BUTYL RUBBER.

2. PLASTICS Light in wt so transportation is easy and cheap. Available in variety of shape and easily

fabricated. Used for storing number of materials. In machines, plastic material is preferred

wherever moving parts are present indicating that it offers less resistant.

Plastics are synthetic resins containing long chains of atoms linked to form giant or macromolecules (polymer).

They have high molecular weight.

TYPE OF PLASTICS

BASED ON UTILITY OF PLASTICS

Rigid materialsFlexible materialsMetallic surfacesPlastic cementsSpecial case plastics