Material balance problems...thanks in advance :D?

Question

1. 800 kg/h of halibut livers containing 23% oil is extracted with 570 kg/h of pure ether. The extracted liners is analyzed and found to contain 1.12% oil, 32.96% ether and 65.92% oil free liners. Find the composition and the weight of extract and percentage recovery of oil

2. Soybean which is used for making textured vegetable proteins contains 15% by weight oil. Suppose that 300lb of solvent containing 2 oil is used to extract oil from 500 lb soybean. The solvent and the soybean flakes are mixed thoroughly and the solution is drained. The flakes are still wet with solution and the oil in the solution is 2lbs. Find the weight composition (% oil ) of the solution

Kitz · Accepted Answer

1. Halibut liver analysis:
total mass = 800 kg/h
mass of oil = 23% of total mass = 184 kg/hr
mass of pure liver = 77 % of total mass = 616 kg/hr

mass of pure ether = 570 kg/h

Extracted liners analysis:
mass of liners = mass of ether + mass of oil + mass of pure liver (oil free liner)

Total Material Balance: streams entering - streams leaving

mass of fresh halibut livers + mass of pure ether = mass of extract + mass of spent halibut
800 kg/h + 570 kg/h = mass of extract + mass liners
mass of extract + mass of spent halibut = 1370 kg/hr ===> equation 1

Component Material Balance: (Liner balance)

Liner from fresh Halibut = Liner from spent halibut
616 kg/hr = 0.6592 x mass of extract

mass of spent halibut = 934.46 kg/hr (insert to equation 1)

mass of extract +934.46 = 1370 kg/hr ===> equation 1

mass of extract = 435.53 kg/hr =======> answer

Composition of extract:
mass of oil = (1.12/100) x 435.53 = 4.87 kg/hr ====> 1.12%
mass of ether = (32.96 /100) x 435.53 = 143.55 kg/hr ====>32.96%
mass of oil free liners = (65.92/100) x 435.53 = 287.10 kg/hr ===> 65.92%

% recover of oil = oil from extract / oil from fresh halibut
% recovery of oil = [4.87 / (0.23 x 800)] x 100% = 2.65% =====> answer

2. Soybeans analysis:
mass of soybean = 500 lbs
mass of oil = 15% of total mass = 75 lbs

Solvent analysis:
mass of solvent = 300 lb
mass of oil = 2% of total mass of solvent = 6 lbs (what that 2? I assume it's 2%)

Solution analysis:
mass of oil = 2 lbs

Total Material Balance: mass in = mass out

mass of soybean + mass of solvent = mass of solution + mass of flakes
500 lbs + 300 lbs = mass of solution + mass of flakes

mass of solution = 800 - mass of flakes ===> equation 1

Component Material Balance: (oil balance)

Oil from soybean + oil from solvent = oil in the solution + oil in the flakes
75 lbs + 6 lbs = 2 lbs + oil in flakes

oil in flakes = 79 lbs

Is there no given % of oil in the solution or in the  flakes? I can't proceed without it.  Also clarify if 2 lbs only is the amount of extracted oil. That's too low. Anyway, hope you've got an idea on how to solve this kind of problem.

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Material balance problems...thanks in advance :D?

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