Process Equipment and Plant Design
In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes

Are less prone to fouling
Can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less
None of these
Are easier to clean

ANSWER DOWNLOAD EXAMIANS APP

Process Equipment and Plant Design
When one of the fluids is highly corrosive and has fouling tendency, it should

Flow at a very slow velocity
Preferably flow inside the tube for its easier internal cleaning
Flow outside the tube, when the flow is counter-current and inside the tube when the flow is co-current
Perferably flow outside the tube

ANSWER DOWNLOAD EXAMIANS APP