Dr. Lamm
Supplemental Instruction
Iowa State University / Leader: / Shawn V.
Course: / CH E 210
Instructor: / Dr. Lamm
Date: / 2-4-2016
Warm Up
FILL IN THE BLANKS
?=moles of desired product formedmoles of undesired product formed
Fractional Excess of A= ?stoichiometric proportion of A moles
?=moles reactedmoles fed
Percent Excess of A= ?
Overall Conversion= ?reactant input to process
Yield=moles of desired product formed? X ?
?=(Moles of Limiting Reagent) X (Fractional Conversion)
?= reactant input to reactor-reactant output from reactor?
Identify the correct DoF analyses and fill in the blanks as appropriate.
? / + no. unknown labeled variables?
- no. independent molecular species balances on non-reactive species
- no. other equations relating unknowns
? / + no. unknown labeled variables
?
- no. independent reactive species
?
- no. other equations relating unknowns
? / + no. unknown labeled variables
+ no. independent chem rxns
?
- no. other equations relating unknowns
Practice Problems
Felder and Rosseau 4.41 p. 188
Seawater containing 3.5 wt% salts passes through a series of ten evaporators. Roughly equal quantities of water are vaporized in each of the ten units and then condensed and combined to obtain a product stream of fresh water. The brine leaving each evaporator is fed to the next one (except the tenth). The brine leaving the tenth evaporator contains 5.00 wt% salt. Draw and completely label a flow chart for the entire process.
Felder and Rosseau 4.46 p. 190
Mammalian cells can be cultured for a variety of purposes, including synthesis of vaccines. They must be maintained in growth media containing all of the components required for proper cellular function to ensure their survival and propagation. Growth media are prepared by blending a powder such as Dulbecco’s Modified Eagle Medium (DMEM) with sterile deionized water. DMEM contains glucose, buffering agents, proteins, and amino acids. Sometimes the growth medium can become contaminated with bacteria, which requires the use of antibiotics. The culture medium is also supplemented with fetal bovine serum (FBS), which contains growth factors for the cells.
Suppose an aqueous stream of cultured cells (SG = 0.90) contaminated with bacteria is split, with 75% being fed to a mixing unit to dissolve a powdered mixture of DMEM contaminated with the same bacteria found in the water. The ratio of impure feed water to powder entering the mixture is 4.4:1. The stream leaving the mixer is combined with the remaining 25% of the aqueous stream and fed to a filtration unit to remove all the bacteria that have contaminated the system, a total of 2 kg. Once the bacteria have been removed, the sterile medium is combined with FBS and an antibiotic mixture PSG (penicillin-streptomycin-L-glutamine) in a shaking unit to generate 5000 L of growth medium (SG = 1.2). The final composition of the growth medium is 66 wt% water, 11 wt% FBS, 8 wt% PSG, and the balance DMEM.