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1) 10000 lb/h of a 40.00% NaoH solution is crystallized through a combined evaporator-crystallizer process. The...

1) 10000 lb/h of a 40.00% NaoH solution is crystallized through a combined evaporator-crystallizer process. The feed enters an evaporator which concentrates it to 50.00% NaOH. The concentrated solution then enters the crystallizer with a built in filter. The crystal product is 95% NaOH crystals with the remaining 5% as adhering mother liquor solution. The mother liquor, containing 45.00% NaOH, is mixed back to the feed before entering the evaporator. Determine the recycle flow rate.

2) Resolve the problem, now considering if the mother liquor is not recycled, but the entire process still generates the same amount of product (crystals) as the original problem. Retain all concentrations given. Determine the amount of feed needed if the recycle stream was removed. Compare the recovery ratio (lb NaOH recovered as crystals/lb NaOH in feed) for the two cases to see the importance of the recycle stream.

Solutions

Expert Solution

So

1.)

by using reflux stream

The recovery ratio is =0.391

2.)

While without using the reflux stream

The recovery ratio is =0.073


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