Process Equipment and Plant Design Lecture Notes

What color are fresh water carrying pipelines in chemical industries?

They are coloured with sea green.

Which material is seldom used for pressure vessel construction?

Rimmed still.

What is the ratio of shear stress to shear strain called?

Shear modulus.

What does a 25 percent cut segmental baffle mean?

The height is 75% of the I.D. of the shell.

When are liquid/petroleum fuel storage tanks built underground?

When the storage capacity is less than 20 kilolitres.

For a fully open globe valve, the May be around what value?

10.

Lug support is most suitable for which type of vessels?

Thick vertical vessel.

What is the highest turn down ratio provided by valve trays?

They have the highest turn down ratio among the types of trays.

What happens to the value of FT with an increase in the number of shell passes?

It remains the same only if the number of tube passes does not change.

What is the triangle pitch hole arrangement in a sieve tray?

Holes are arranged in triangular pitch of 2.5 to 5 times the hole diameter.

What is the minimum shell thickness for carbon steel in a shell and tube heat exchanger?

It is in the range of 5-11 mm.

What is called the stress developed in a material without any permanent set?

Elastic limit.

What is the definition of tube pitch in a shell and tube heat exchanger?

Shortest centre to centre distance between adjacent tubes.

What assumption is not valid in continuous binary distillation for calculating equilibrium stages?

Molar latent heat of the two components are equal.

What is the efficiency formula for most refinery columns?

η = 17 - 61.1 log μ.

The value of fouling factor depends on which characteristics?

All: characteristic of process fluid, velocity of process fluid, suspended solids in the fluid.

What is the typical cap diameter for a bubble cap distillation column greater than 1.2 metres?

Approximately 30 cms.

What is the tube side pressure drop in a 1-2 heat exchanger compared to a 1-1 heat exchanger?

It is about 4 times.

If impeller diameter increases by 20%, what happens to the impeller speed for constant power input?

It should be decreased by a factor of (1.2)3/5.

In a heat exchanger, how can shell side fluid velocity be changed?

By changing the tube layout and pitch.

Where does the maximum tensile strength occur in a thick cylindrical vessel?

At the inner surface.

What is the desirable limit for LMTD correction factor in heat exchanger design?

Not less than 0.99.

Which does not fail a riveted joint?

Tearing of rivets.

A triangular pitch tube layout allows for what compared to square pitch?

Permits the use of fewer tubes.

Which supports are suitable for horizontal vessels?

Bracket supports.

In a multipass shell and tube heat exchanger, the shell side cross flow area does not depend on which factor?

Pitch.

Two iron pipes of the same nominal diameter will have the same what?

Outside diameter.

What is the assumed steam side heat transfer coefficient for design under ordinary conditions?

About 2500 kcal/hr.m².°C.

Which statement about cylindrical process vessels is wrong?

Fouling factor of river water is less than that of sea water.

What does a Lessing ring do?

It is formed by adding a partition across the centre of a raschig ring, increasing the area by about 20%.

What is the apex angle of conical bottom heads used in chemical process equipment?

Usually 60°.

What is the maximum size of packings allowed in packed columns?

Larger than 50 mm.

What is always more in the shell side as compared to triangular pitch ventilation?

The heat transfer coefficient.

What is the correct use of 'factor of safety' in equipment design?

It is the ratio of ultimate stress to working stress.

What is the pressure drop per metre height of packing in