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Materials of plant construction
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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