HW 9 - SP5 - Scaling Up a Chromatographic Separation of Fumarase - 5 pts
Ten grams of the enzyme fumerase are being purified in an ion exchange chromatography column. At a superficial velocity of 30 cm/h, the peak exits the column in 93 min and the standard deviation of the peak is σt0 = 12 min.
a.) How long must we purify to obtain a 90% yield ?
b.) If we increase the flow to 60 cm/h, how long must we run to obtain the same 90% yield if the process is controlled by diffusion within the packing particles ?
c.) How long must we wait if the process is controlled by external mass transfer ?
d.) How long must we wait if Taylor Dispersion controls the rate of the process ?
e.) How long must we wait if the column actually contains equilibrium stages ?
a.) How long must we purify to obtain a 90% yield ?
b.) If we increase the flow to 60 cm/h, how long must we run to obtain the same 90% yield if the process is controlled by diffusion within the packing particles ?
c.) How long must we wait if the process is controlled by external mass transfer ?
d.) How long must we wait if Taylor Dispersion controls the rate of the process ?
e.) How long must we wait if the column actually contains equilibrium stages ?
posted by Dr. B at 8:42 AM
7 Comments:
when we scale up, does "to" alway be the same? This mean when we scale up only the width of the peak will be difference?
No. See slide 2 from Wednesday's PPT. t0 changes.
I think the answers you provide may be a little off. I'm not sure about this but in lecture today we were talking about whether t'=0 or t'=-infinity in the equations. I did it with t'=-infinity because that seems to make the most sense conseptually. My answers are a little lower by by a few minutes. You think that this is the right way to do it?
I also get numbers a few minutes lower than what you got
For Sp5, part b, it appears that you used sigma*t0 as 12min, when sigma is constant from before, but t0 is half of what it was in part a. So should I use sigma*t0=12 min or 6min, which I think it is.
Bill Nye:
You are correct. I trusted my source. My calculations yield the following approximate answers.
a.) 108 min, b.) 57 min and e.) 54 min
I hope these match your results !
Taz:
You are correct that t0 is cut in half to 46.5 min in parts b through d. But sigma*t0 is not cut in half. Use the boxed scale-up eqns in the powerpoint to determine how sigma*t0 changes when the velocity is doubled. You should get roughly the new values of sigma*t0 that I showed in class (also i the powerpoint).
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