3.33 You are starting up a bioreactor containing mammalian cells to do the follo

Question

3.33 You are starting up a bioreactor containing mammalian cells to do the follow- ing chemical conversion: In addition to the cells, the bioreactor contains many charcoal pellets. Based on previous research, you know that the mammalian cells have better long- ability when attached to the charcoal pellets as compared to just being in suspension. (Cells that exhibit this pattern are known as anchorage-depend term st ent cells. Water containing A2B and BC flows into the bioreactor at a flow ra 0.10 i. The concentration of A2B in the input stream is 70.0 g/L. The concentration of BC in the input stream is 140 g/L. A2B, BC, AB and C are all fully dissolved in water and do not contribute substantially to the density of the solution. The molecular weights of A, B, and C are 2.0 g/mol, 3.0 g/mol, and 4.0 g/mol, respectively. e reactor runs continuously. The output stream empties into a very rge container (Figure 3.37). Since there is no on-line detection for the outlet stream, samples are taken from the container, and the concentrations of the e determined. Assume that the large container is well la mixed. a) You run the e bioreactor for 4.0 days. During that period, the entire outlet s captured in the large container; none is emptied. You sample the con- tainer after 4.0 days and determine that the concentration of A2B is ased on this information, determine the outlet flow rate of A2B. eterme the reaction rate, R, of the system. What are the fractional con- 3. 5 g/L. B versions of A2B and B C? manage to borrow a n instrument to do on-line detection right at the end your 4.0-day experiment. You sample the outlet stream (not the container) n determine that the outlet concentration of AB is 90.0 g/L. Is this meas urement consistent with your results from parts (a) and (b)? Why or why not?

Explanation / Answer

a) Mass in Flowrate = 0.1 L/min

Mass out flowrate = Mass in flowrate (Because density is same of both in & out mass= Density of water)

=> Volume collected in 4 days in tank = 4*24*60*.1 =576 litre

Concentration of A2B in tank = 3.5 g/litre

Mass of A2B in tank = Concentration of A2B in tank*Volume collected in 4 days in tank=3.5*576=2016 g

Outlet mass Flowrate of A2B = Mass of A2B in tank/time of collection = 2016/(4*24*60)=0.35 g/min

b) Reaction rate = (In volumetric flowrate*Concentration of A2B in inlet feed-Outlet mass Flowrate of A2B)/Molar mass of A2B

Molar mass of A2B = 2*Atomic mass of A + 1*Atomic mass of B = 2*2+1*3=7 g/mol

=> Reaction rate=(.1*70-.35)/7= .95 mol/min

Fractional conversion of A2B = (In volumetric flowrate*Concentration of A2B in inlet feed-Outlet mass Flowrate of A2B)/(In volumetric flowrate*Concentration of A2B in inlet feed)=(.1*70-.35)/(.1*7)=95%

Molar Mass of BC = Atomic mass of B+Atomic mass of C = 3+4 = 7 g/mol

Inlet Molar flowrate of BC = Inlet volumetric flowrate*Concentration of BC/Molar mass of BC = .1*140/7=2 mol/min

Since A2B one mole reacts with one mole BC

=> Fractional converison of BC = Reaction rate/Inlet molar flowrate of BC = .95/2=47.5%

c) A2B+BC=>2AB+C

=> 1 mole A2B reacts and produces 2 moles AB

Using tank data,

=> Concentration of AB in outlet stream = 2*reaction rate/out volumetric flowrate =2*.95/.1=19 mol/litre

Molar mass of AB= Atomic mass of A+Atomic mass of B=2+3 = 5 g/mol

=>  Concentration of AB in outlet stream (g/litre)=19*5=95 g/litre

On line measuring unit gives Concentration of AB = 90 g/litre which is different from what we calculated using tank data. Therefore, data are not consistent

Concentration of AB as found using tank data is more than the observed value using on-line analysis. Reason is, since Mass was kept for 4 days before taking the analysis, reaction happened in tank also in this residing time. Hence more conversion of A2B to AB happened and hence concentration of AB is higher in tank than in outlet stream of reactor.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.