Q19: Which of the Separation Schemes shown below would you recommend for the given FEED composition (mole%)?
FEED Pressure is 50 barg.
A. Separation Scheme – I
B. Separation Scheme – II
C. Separation Scheme – III
D. Insufficient Information
A; Since there are multi-components from light ends to heavier ones and the FEED is at sufficiently high pressure, a 3 stage separation is more likely to be recommended.
Q20. You are given 8 identical looking coins. One of them is heavier than the rest of the 7 (all the others weigh exactly the same). You are provided with a simple mechanical balance and you are restricted to only 2 uses. Find the heavier coin.
For convenience sake, let’s name the coins 1-8. First we weigh {1,2,3} on the left and {4,5,6} on the right. There are three scenarios which can arise from this.
If the left side is heavier, then we know that one of 1, 2 or 3 is the heavier coin. Weigh {1} on the left and {2} on the right. By doing this, we will know if 1 or 2 is heavier. If they balance out, then 3 is the heavier one.
If the right side is heavier, then we know that either 4, 5 or 6 is the heavier coin. Weigh {4} on the left and {5} on the right. By doing this we will know if 4 or 5 is heavier. If they balance out, then 6 is the heavier one.
If {1,2,3} and {4,5,6} balance out, then we know either 7 or 8 is the heavier one. Weigh both of them to find out which one is heavier.