Materials of Plant Construction

7/28/2019 Materials of Plant Construction

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MATERIALSOF PLANT CONST

Prepared by : Mr. Jitendra L. Patel


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FACTORSAFFECTINGSELECTIONOF

MATERIALFORPLANTCONSTRUCTION.

3 Type of factors.

1. Chemical factors

2. Physical factors

3. Economical factors


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CHEMICALFACTORS

1. Contamination of the product by material of plant lead toinstability, 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.


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CHEMICALFACTORS

2.The effect on the material of plant by drugs andchemicals.

Acids, Alkalis and Oxidizing agent and tannins may affect

the material of construction.

Allows and Plastic have a corrosion resistant properties.


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PHYSICALFACTORS

1. Adequate Mechanical Strength.

2. Erosion

3. Weight

4. Ease of fabrication

5. Thermal Expansion

6. Thermal Conductivity

7. Cleansing

8. Sterilization 9. Transparency


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Strength

The material should have sufficient strength so thatit can withstand the stress to which the material issubjected in the production.

Iron and Steel satisfy this property.

e.g. The packing material should withstand therigors of handling and transportation.

Mass

The equipment should have a light weight so it iseasy to transport.

Plastic materials employed for the manufacture ofcontainer for use of pharmaceuticals andcosmetics bcz of its light weight.


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Wearproperties

There is a possibility of friction between themoving parts.

During milling and grinding surface wear off andthis materials will be incorporated into powder as

impurities.

Thermalconductivity

The materials used for evaporators, dryers and heatexchanger should have a good thermal conductivity.

Resistant film retard the rate of heat transfer.

Thermalexpansion

If the material has high coefficient of expansion , thetemp changes cause increase in stress and risk offracture.

The material should be able to maintain size andshape of equipment at working temperature.


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Transparency

It permits the visual observation of thechanges during a process.

For this reason borosilicate glass has beenused in the construction of reactors,fermentors etc.

Economicfactors

Initial costs and maintenance of the plantmust be economical.

Low wearing qualities and lower

maintenance. Higher initial cost is more economical in the

long run.


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Ease offabrication

During fabrication, the materials under go variousprocesses such as casting, welding, forging etc.

Glass and plastic can be easily molded into

containers of diff. size and shape.

Cleansing

Smooth and polished surfaces allow the process ofcleansing easy.

Stainless steel and glass are easy for cleansing.

Sterilization

In the production of parenterals, ophthalmicproducts, antibiotics and biologicals, sterilization isan essential step which is obtained by autoclaving .

The material should be able to withstand the steampressure.


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Material of plant construction

Ferrous

Non-Metals

Cast

Iron

Steel

Carbon

Stainless

Steel

InorganicGlass Organic

Non-FerrousMetals

Aluminum Lead

Rubber Plastic


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FERROUSMETALS

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


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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.


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Cheap

Resistant to conc.. H2SO4. HNO3, and dilute alkalis.

It has low thermal conductivity so used for constructionof outer jackets of steam pans.

Advantages

It is very hard and brittle so difficult to machine.

It is attacked by dil H2SO4. HNO3 as well as conc. HCl. It has low thermal conductivity so not used for heat

transfer in steels.Disadvantages

Supports for plant.

Jackets of steam pans.

Lining with enamel, plastic or suitable protectivematerials

Uses


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Modifications

1. Gray Cast iron

3. HighSiliconcast Iron

4. Nickel resistantcast iron

2.MalleableIron


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GRAYCAST IRON

Carbon Silicon

Composition

Low cost Easy to cast into intricate

shades and linings,Properties

Brittle

Poor resistant to impact and

shock.

Disadvantages


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MALLEABLE IRON

White cast iron Carbon 2-5 %Composition

Corrosion resistant

Type 1 easy to machine.Properties

Type 2 less easy tomachine.

Disadvantages


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HIGH SILICONCAST IRON

Cast iron Silicon 13- 16 %Composition

Resistant to corrosion, oxidizingand reducing environment.

Used in H2SO4 services.Properties

Not easily machined andwelded.

Disadvantages


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NICKEL RESISTANTCAST IRON

Superior toughness

Impact resistant.

Easy to weld and machine.

Corrosion resistant and heat

resistant.

Properties

Oxidizing agents are highlydetrimental.

There is a Little attack fromneutral or alkaline solution.

Disadvantages

CARBON STEEL OR MILD STEEL


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Cheapest Easily weld able and used in

fabricationAdvantages

Carbon steel has limited resistant to

corrosion. It can be improved bypreparing alloys.

It reacts with caustic soda, brine andsea water. Alloying can reduce thisproperties.

Disadvantages

Used in construction of bars, pipesand plates.

Used to fabricate large storage tanksfor water and organic solvents.

Also used for supporting structures.

Uses

CARBONSTEELORMILDSTEELCARBONSTEELISANIRONALLOY, WHICHCONTAINSONLYA

SMALLPERCENTAGEOFCARBON.


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Modifications

Alloying it

with othermetals alter

the properties

1. Nickel improvestoughness, corrosion

resistant

3. Molybdenum

providesstrength atelevated temp.

4. Silicon increaseshardness, abrasive and

corrosion resistant

2. Chromiumincreases

hardness,abrasive and

corrosion resistant


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Different Types & Alloys of Carbon Steel

1.Low Allow Steel

2.Alloying withNickel

3.Allowing withSilicon Chromium.

Low conc. of Iron,carbon, manganese,Nickel, Chromium &

molybdenum.

Nickel.

Nickel, Chromium.

High mechanicalstrength.

Corrosive resistantto environment.

Increase hardness.

High corrosionresistant.

Abrasion resistant.

Corrosion resistant.

Resistant tooxidation.

Variety of Carbon Composi t ion Advantages

Al low


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STAINLESSSTEEL It is an allow of iron.

It contains chromium and nickel, which makes the steelcorrosion 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.


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MARTENSITIC

Chromium : 12- 20 %

Carbon : 0.2-.4 %

Nickel up to : 2.0 %

Composition

Mildly corrosion resistant atm % organicexposure.Advantages

Ductility is poor.Dis-

Advantages

Sinks, bench tops, storage tanks, bucketsetc.Uses


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AUSTENITIC

Chromium : 13-20 %

Carbon : 0.1 % < 0.25 %

Nickel up to : 6-22 %

Composition

Highly corrosion resistant.

Readily cleaned, sterilizable.

Easy to weld.

Advantages

Not easy to machine.Dis-

Advantages

Fermentors, storage vessels, evaporators,extraction vessels, buckets, funnels..Uses


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FERRITIC

Chromium : 15-30 %

Carbon : 0.1 %

Nickel up to : nil

Composition

Better corrosion resistant.

Easy to machine.

Resistant to temp and temp.

Advantages

Not good against reducing agents, HCl..Dis-

Advantages

Tower linings, Baffles, Separator, tower,heat exchanger, tubings, condensers,

furnace parts, pumps shafts, valve parts..

Uses


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Non-ferrous

metals

1.Aluminium

2.Lead

1 A


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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.


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High resistant to atm conditions, industrialfumes, vapour and fresh or salt waters.

Thermal conductivity of Al. is 60 % that of

pure copper.

Advantages

Mechanical strength decrease above 150 0 C.

Al. can not be used with strong caustic

solution. Many mineral acids attack Al.

Oxide & hydro-oxide films form rapidly whenexposed.

Disadvantages

Preferred for food and pharmaceutical use.

Used in heat transfer.

Used as storage containers.

Used in pdtn of citric acid, gluconic acid andstreptomycin.

Most useful for construction of drums,

barrels, rail tankers.

Uses


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2.LEADIt has the lowest cost.Used as collapsible tube material

particularly for non-food products such

as adhesives, inks, paints andlubricants.

Lead tubes with internal linings are used

for fluoride tooth-paste.

Lead chamber process is used in the

manufacture of sulphuric acid.

It has the lowest cost


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It has the lowest cost.

Advantages

Lead has low melting point and hence

posses poor structural qualities. It has a high coefficient of expansion.

So temp strain result in permanentdeformation.

Disadvantages

Used as collapsible tube material particularlyfor non-food products such as adhesives, inks,paints and lubricants.

Lead tubes with internal linings are used forfluoride tooth-paste.

Lead chamber process is used in themanufacture of sulphuric acid.

Little use in pharma bcz of risk of contamination

even in traces produce toxicity.

Uses


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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 theconstructions of pipes, valves, vessels designed for

operations at high temp, fluctuating temp or vacuum.


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NON-METALINORGANIC

1.GLASS

2.GLASSEDSTEEL


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1.GLASS Sand : Silica pure (SiO2) : Base material

Soda Ash : Na2CO3 : Improves the properties.

Lime stone : CaCO3 : Improves the properties.

Cullet : Broken glass : Fusion agent

Composition

Superior protective qualities, attractive and low cost.

Chemically inert to large extent and available in variety of sizes,shapes and colors.

Offer excellent barrier against many elements except light.Advantages

UV rays and sunlight are harmful to certain ingredients and causedeterioration.

Protection against light can be obtained by amber colored bottleand against IR rays by green color glass.

Fragility and weight.

Dis-

Advantages

Mostly used in pharmaceutical industries as a containers.Uses


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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.


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1. GLASS

The 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.

Diff t T f Gl


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Different Types of Glass

I

II

III

IV

Highly resistantborosilicate.( Alkali &earth cations arereplaced by boron)

Treated soda-limeglass

Soda-lime glass

General purposesoda-lime glass.

Resistant to alkalileaching, less brittle, lowthermal expansion, easyto clean & sterilize.

Surface alkali isneutralized by sulphur

dioxide vapors. Glasssurface is resistant towater.

It release comparativelymore alkali. It offers

moderate hydrolyticresistance

Containers for buffered7 unbuffered, aqueoussolution & injectables.

Containers for buffered,aqueous solution withpH below 7.0, drypowders, oleaginoussolution.

Dry powders,oleaginous solutions.

Not for parenterals,used as containers fortablets, oral solutions,suspensions, ointments&liq. For external use.

TypesGeneral

DescriptionProperties Uses

2.GLASS STEEL


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2.GLASSSTEELGlassed steel is an inorganic pdt of fusion, which is cooled toa rigid condition without crystallizing.

It requires special consideration in its design & use.

Glassed steel combines the corrosion resistance of glasswith the working strength of steel.

Excellent resistance to all acids except HF and hot conc..H2SO4.

It can be attacked by hot alkaline solution. Brittle & gets damaged by thermal shock. Hence protected

using glass lined with epoxy polyester fiber glass.

Glass linings are resistant to

All conc. of HCl up to 1200C.

All conc. of HNO3 up to boiling point.

Dilute conc. of H2SO4 up to boiling point.

Acid resistant glass with improved alkali resistance ( up to pH12)

Advantages

Used for handling of strong acids, alkalis and saline solutions.

For small scale manufacture and pilot plant work glassed steelvessels are used.Uses


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NON-METALORGANIC

1.RUBBER

2.PLASTIC


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RUBBERUsed as such as a lining material for

the construction of plants.

Type of rubber

1. Natural Rubber

2. Soft rubber.

3. Hard Rubber4. Synthetic Rubber.

R bb i t ll i l bt i d


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Natural

Rubber

Rubber is naturally occurring polymer obtained aslatex from rubber trees.

It is common example of an elastomer.

Elastomer is a substance that can be stretchedreadily regains its original form.

Soft

Rubber

The naturally occurring polymer is known as softrubber.

It is a polymer of monomeric isoprene (C5H8). It is resistant to dil. Mineral acids, dil. Alkalis and

salts.

It can be attacked by a oxidizing media, oils &organic solvents.

Used lining materials for plants.

Addition of carbon black to the soft rubber giveshardened rubber.

Used in making tyres, tubes, and conveyor belt.


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HardRubber

When soft rubber is mixed with sulphur, warmed &set into a given, it retains its form.

The sulphur combines with the polymeric chainsof rubber and cross links between them. Thisprocess is known as vulcanization.

Soft rubber with 25 % sulphur is known as HardRubber.

hard Rubber is used for making gloves, bands,

tubes, and stoppers.

SyntheticRubber

Synthetic Rubber is resistant to oxidation, solvents,oils and other chemicals.

Synthetic Rubber is thermoplastic.

Vulcanization of rubber is possible.

Rubber can be hardened by adding carbon black.


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SOMEVARIETIESOFSYNTHETICRUBBER.

Five type of Synthetic Rubber

1. Neoprene

2. Nitrile Rubber3. Butyl Rubber

4. Silicon Rubber

5. Polyisoprene


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1. NEOPRENE (POLYCHLOROPRENE)

Properties

Does not burn readily like naturalrubber.

Stable at high temp.

Uses

Use as insulating material in electriccables, conveyor belts in coal mine,rubber stoppers, cap liners, dropperassembly for eye drops.


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2. BUTYL RUBBER.

Properties

Resistant to mineral acids andalkalis, concentrated acids (exceptnitric acid and sulphuric acid).

Uses

Used for closure of freeze dried

pdt containers bcz of its low watervapor permeability.


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2


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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.


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Advantages

Low thermal and electricalresistance.

Excellent resistance to weakmineral acids.

Unaffected by inorganic salts.

Resistant to small changes to pH.

Dis-advantages Low mechanical strength.

High expansion rates.

TYPE OF PLASTICS


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TYPEOFPLASTICS Thermosetting plastics can be formed

under heat and pressure. But this can

not be softened or remoulded, oncehardened.

Some are made of phenolic and urea.

Thermosettingplastics

They are formed by the application of heatand pressure can be softened andremouled.

e.g. of thermoplastic material and their use

Polyethene: cables, buckets, pipes.

Polypropylene: milk, cartons, ropes.

Polyvinyl chloride: gloves, water proofgarments.

Teflon: gaskets, coatings.

Thermoplastic

plastics


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BASEDONUTILITYOFPLASTICS

Rigid materialsFlexible materials

Metallic surfacesPlastic cements

Special case plastics

These are phenolic resins with various inert


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Rigidmaterials

These are phenolic resins with various inertfillers.

Used in fabrication of number of items.

Light in weight.

Used in gears, pipes, fittings, ducts, valves,vessels.

Resistant to corrosion except oxidizingsubstance and strong alkalis.

Flexiblematerials

These are thermoplastic materials.

These materials can be rigid or flexible

depending upon the amt of plastcizeradded.

They are used in fabrication of tanks,pipes, funnel, buckets.

Plastics of polyethelene or polyvinyl chloride types


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Metallic

surfaces

p y p y y ypare used along with plasticizer for the coating ofmetallic surfaces.

These are used to protect the metal from corrosion.

These linings are applied on tanks, vessels, stirrerand fans.

Plasticcements

Used for spaces between acid resistant tilesand bricks.

Specialcase

Plastics are used as guards for moving partsof machinery.

Nylon and PVC fibers woven into filterscloths and are used for aseptic screening.

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