PROGRAM
NATIONAL DIPLOMA
CHEMICAL ENGINEERING
SUBJECT
CHEMICAL ENGINEERING
TECHNOLOGY IIIA
CODE
CMTA321
DATE
SUMMER EXAMINATION
NOVEMBER 2007
MODEL ANSWERS
QUESTION 1
1.1.
1.2.
1.6.
1.3.
If one of the reactants is in excess, it will
build up in the plant as there is no
opportunity for it to leave.
1.4.
Nitrogen in = nitrogen out
1.5.
Mass flow-rate in = mass flow-rate out as required.
QUESTION 2
2.1.
Energy for 1kg of fluid:
2.2.
Consider 1kg of fluid moving from point 1 to point 2:
Assume T = constant, i.e. U 1 = U2
For incompressible flow, ρ = constant
QUESTION 3
3.1.
3.2.
Use the compressible gas equation for isothermal flow:
Re>2100 therefore the flow is turbulent. Need to get f from the friction factor graph.
3.3.
3.4.
Modes:
Convection from air to pipe outer surface.
Conduction through pipe.
Convection from inner pipe wall to air.
QUESTION 4
4.1.
4.2.
4.3.