Month: March 2019

Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than ______________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop?

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Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than ______________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop?

A. 25
B. 50
C. 75
D. 150

Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger________________?

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Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger________________?

A. Permits the use of less tubes in a given shell diameter
B. Facilitates comparatively easier external cleaning because of large clearance
C. Permits the use of more tubes in a given shell diameter
D. Both B. and C.

To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of_________________?

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To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of_________________?

A. (1.2)3/2
B. (1.2)3/5
C. (1.2)2/3
D. (1.2)5/3

In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference ______________________?

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In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference ______________________?

A. Is always less than arithmetic average value
B. Is always more than arithmetic mean value and the geometric mean value
C. Is always less than arithmetic mean value, but more than geometric mean value
D. May be either more or less than geometric mean and arithmetic mean value depending upon
whether the flow of stream is co-current or counter-current