Temperature control of an exothermic chemical reaction taking place in a CSTR is

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Question
Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are
Options
A. air to open valve with the controller direct acting.
B. air to close valve with the controller indirect acting.
C. air to open valve with the controller indirect acting.
D. air to close valve with the controller direct acting.

Correct Answer

air to open valve with the controller indirect acting.

1. In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of
Options
A. relative roughness.
B. absolute roughness.
C. friction co-efficient for flows at equal Reynold number.
D. all (a), (b) & (c).

2. The terminal velocity of a small sphere settling in a viscous fluid varies as the
Options
A. first power of its dimeter.
B. inverse of the fluid viscosity.
C. inverse square of the diameter.
D. square of the difference in specific weights of solid & fluid.

4. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the
Options
A. discharge.
B. suction.
C. suction minus vapor pressure of the liquid at suction temperature.
D. discharge minus vapor pressure of the liquid at the discharge temperature.

7. Which of the following is the most adverse factor challenging the choice of mercury electrolytic cell process for the production of caustic soda?
Options
A. High cost of mercury.
B. High specific gravity of mercury.
C. Non-availability of high purity mercury.
D. Pollution of water stream by mercury.

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