Chemical Engineering : Problems: Heat Exchangers Chemical Engineering Notes | EduRev
Questions for Practice (Module 8)
|Q.1||Under what conditions it is advantageous to use U-tube heat exchanger?|
|Q.2||What is the physical meaning of LMTD?|
|Q.3||Why correction factor for LMTD is required?|
|Q.4||If we have to process a corrosive liquid in a heat exchanger, where will you prefer to send it, tube-side or shell-side of the heat exchanger. Support your answer with the reasoning.|
Show the temperature profile of a heat exchanger (condenser) where saturated water vapour is condensing in the shell side and the cold liquid is flowing in the tube side. It should be noted that the condensed water is not sub-cooled and the tube-side water is not vaporized.
What are the different types of tube arrangements in a shell-and-tube heat exchanger? Explain the advantages and drawbacks of the arrangements.
What is the basic difference between 1-1 and 2-4 heat exchanger? What is the basis to choose a particular type (with respect to pass) of heat exchanger.
Liquid ammonia feed is to be pre-heated from 30° C to 60° C before pumping to the reactor. The liquid ammonia is heated with the help of another stream of hot water at 90° C. The properties of the streams may be collected from the available literatures.
Bombay high crude oil is to be heated from 15° C to 55° C at the rate of 1,50 ton/h using a stream from the plant. The crude oil is pumped in to the tube and the heating stream is pumped into the shell side of an available heat exchanger. The heating stream enters in to the tube at 150° C and leaves the tube at 110° C. The average properties of both the fluids are given below. The available heat exchanger (1-2 pass) has shell diameter of 23¼ in. The shell has 324 tubes, ¾ in. OD, BWG 14 (wall thickness), 12 feet long arranged on 1 in. Square pitch and supported by baffles with a 25% cut, spaced at 9 in interval. You need to find the suitability of this exchanger for the purpose. What will be the allowable fouling factor?
cp , J/g. ° C
k, W/m.° C
Hot water enters a counterflow heat exchanger at 95°C. This hot water is used to heat a cool stream of water from 8 to 40° C. The flow rate of the cool water is 1.2 kg/s, and the flow rate of the hot water is 2.7 kg/s. The overall heat-transfer coefficient is 850 W/m2°C. What is the area of the heat exchanger and its effectiveness?