Type
Quiz
Book Title
Chemical Process Safety: Fundamentals with Applications-- 4/e 4th Edition
ISBN 13
978-0134857770

978-0134857770 Chapter 4 Part 2

December 2, 2020
4-12.
Turpentine density = 55 lbm/ft3
a. Compute the total volume spilled by the change in liquid level:
b. Determine the maximum spill rate from Equation 4-12:
c. Use Equation 4-18 to determine the time required for the level to drop to 13 ft above
the bottom.
15 ft
13 ft
17.9 ft
7 ft
Leak, 0.1 in diam.
15
Substituting:
Solve for t with units of seconds. There are two roots:
4-13. The best approach is to use the steam tables for an isenthalpic flash.
Solve for the fraction flashed by mass:
At the initial conditions.
The quantity flashed is then:
16
If we use Equation 4-87 instead,
We can also use Equation 4-91,
From the steam tables
Substituting into Equation 4-91:
This is close to the other values.
4-14. a. The pipe is threaded into the tank. If the pipe breaks off, it usually breaks off just
b. Use Equation 4-12:
Substituting into Equation 4-12:
c. Need to determine the total volume of the vessel.
Then the total draining time, assuming a constant draining rate, is:
d. For a pool on the floor of 1-cm depth,
The area of the pool is then,
e. Use Equation 3-12,
18
f. Use Equation 3-9 or Equation 3-14.
Substituting into Equation 3-9,
4-15.
1
19
Then it is seen that:
The mechanical energy balance then reduces to:
The various terms are:
The friction term must consider entrance, pipe friction and exit effects. It is given by,
From Equation 4-39,
Substituting,
c
Re 2
g


Returning to the ME balance above,
20
PROCEDURE:
22
4-20. This is a complicated problem involving a mechanical energy balance. For part a the
velocity can be determined and the solution is direct. However, part b is trial and error
since the velocity is not known.
The geometry for this problem is shown below:
For the crude oil:
The final height of oil in the destination vessel, if all oil transferred, is:
a. The required pipe velocity to move all the oil in 1 hour is:
23
We need to size the pump for the worst case pumping situation. In this case, the
b. A 100 HP pump is 74.57 kW. The spreadsheet solution is shown below. All the
c. The conclusion is that this is not a viable method for emergency transfer of liquid
26
4-17. a. From a mechanical energy balance for incompressible flow:
The maximum velocity will occur if: a) the pressure drop across the pump is small, b)
no change in height, and c) no friction. Then the ME balance reduces to:
But
Then,
Solving for u,
b. 50 mm diameter = 0.05 m
Substituting into the equation:
The mass flow is: