Chemical Engineering MCQs

For a cylinderical vessel of moderate height, the weld joint efficiency for joints parallel to the cylinderical axis is given as 1.0, while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylinderical vessel, what value of weld joint efficiency should be used ?

by
0.8
0.9
1
(0.8)0.5
✅ The correct answer is option A.

Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to

by
hG = 1.004G0.37
1.004G0.8
hG = 0.0176G0.37
0.0176G1.37
✅ The correct answer is option A.

A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the __________ mean of P₁ and P₂.(where, P₁ and P₂ are initial and final pressures respectively)

by
A. Logarithmic
B. Arithmetic
C. Geometric
D. Harmonic
✅ The correct answer is option C.