Problem 11-12. Liquid levels in storage tanks are frequently determined by
measuring the pressure at the bottom of the tank. In one such tank the
material stored in the tank was changed and an overflow resulted. Why?
Solution for Problem 11-12.
Problem 11-13. An operator was told to control the temperature of a reactor
at 60°C. He set the set point of the temperature controller at 60. The
scale actually indicated 0 to 100% of a temperature range of 0 to
200°C. This caused a runaway reaction that overpressured the vessel.
Liquid was discharged and injured the operator. What was the set point
temperature the operator actually set?
Solution for Problem 11-13.
Problem 11-14. A light in the control room of a chemical plant indicated whether a valve was
closed or not. In reality it indicated only the status of the signal being sent to the valve.
The valve did not close when it should have, and the plant exploded. Why? How would
you prevent this problem?
Solution to Problem 11-14.