Map Caffeine is often added to headache medications because it affects the flow
ID: 1009741 • Letter: M
Question
Map Caffeine is often added to headache medications because it affects the flow of blood in vessels and may enhance the pain relieving qualities of the medication. You have been tasked with evaluating one process that extracts caffeine from a coffee slurry, and you decide to study a small scale version of the process. A coffee slurry containing a mass fraction of 0.01 g caffeine/g, 0.08 g other solids/g, and 0.91 g water/g is fed to a mixer at a rate of 850.0 g/min. Na2CO3 is added to the mixer such that the mass ratio of NazCO3 to coffee slurry is 0.0500. This aqueous solution proceeds to an extractor where CH2Cl2 is added such that the mass ratio of CH2Cl2 to coffee slurry entering the extractor is 0.410. Two streams leave the extractor. The first is a mostly aqueous stream that leaves the process containing some caffeine, all of the other solids in the original slurry, all of the Na2CO3, all of the water and 2% of the mass of CH2Cl2 entering the extractor. The second stream contains the remaining caffeine and CH2Cl2, and enters an evaporator that completely vaporizes the CH2CI2. The vaporized CH2Cl2 is condensed and is merged with the fresh CHzCl2 rocess othe num am bereue. rform a g CH2Cl2 min g Na2CO3 min m2 E g CH2Cl2 min g CH2CI2/min g coffee slurry/min Extractor Mixer Evaporator X1 caffeine/min g caffeine/g g mostly aqueous solution/min g other solids/g X2 g caffeine/aExplanation / Answer
Iam giving all the answers in mass flow rates just convert them to mass fractions wherever asked
Basis: m1= 850 g/min
Let x1 is caffiene x2 is othersolids x3 is water
X1= 0.01*850=8.5g/min
X2=0.08*850=68g/min
X3=0.91*850=773.5g/min
M2=0.05*850=42.5g/min na2co3
Total slurry entering extractor is 892.5g/min
M4=0.410*892.5=365.925g/min ch2cl2
X5=68g/min
X6=42.5g/min
X7=773.5g/min
X8=7.3185g/min(0.02*365.925)
M6=365.925-7.3185=358.6065g/min
M7= 0.960*8.5=8.16g/min
X4=8.5-8.16=0.34g/min
M3=891.6585g/min
M5=365.925+358.6065=724.5315g/min
Ratio of recycled to fresh= 358.6065/365.925=0.98
To find mass fractions divide the individyal flow rate to total mass flow rate
Example x4=0.34/891.6585=0.0003813
Similarly find remaining mass fractions
Thank you and all the best