CHE 411 OSU Chemical, Biological and Environmental Engineering Fall 2017
Mass Transfer Operations
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Name: __________________________________
Homework Assignment #7b (extra credit)
Due Thursday, December 7, 2016 by 5:00 PM in the CBEE main office (Johnson 116).
Please attach a copy of this assignment sheet to the front of your homework assignment.
Problem 1. You are working on a process to produce methanol (MeOH) by the partial oxidation
of waste methane gas. The resulting methanol vapor is recovered from the reactor effluent by
absorbing it into tert-amyl ethyl ether (TAEE). Your team has been tasked with the preliminary
design of a counter-current extraction cascade to remove the methanol from the TAEE, so that
the TAEE can be recycled to the absorber. Pure water will be used as the extraction solvent.
The MeOH-TAEE feed comes from the absorber unit at a flow rate of 30 kgmole/hr, and
contains 74 mole% MeOH. Water is supplied to the cascade at 25°C and a rate of 1700 L/hr.
a) Find a primary literature source for good LLE data for TAEE/MeOH/water systems at the operating temperature.
Hint: Use the search function provided by the journal web site to find a recent (since
2000) report in the Journal of Chemical Engineering Data (J. Chem. Eng. Data). Please
provide a hard-copy of the first page (title, authors, citation) of the paper.
b) Using the experimental data provided in your reference, create a triangle diagram for your extraction system. Provide a citation to the data source, including primary author,
year, journal volume/pages, and DOI (what’s a DOI?!), directly on the triangle diagram.
Note: This is the major source of points in this assignment, so please format your
triangle diagram professionally and neatly.
c) Estimate the recovery of methanol into the aqueous extract, if the raffinate contains 2 wt% MeOH. How many real extraction units will be required for the separation, if your
extraction units are about 30% efficient? Your calculations and any figures, symbols, or
diagrams must be neatly drawn and clearly legible for full points.
d) Due to space limitations at the plant site on the Hawaiian coast, your extraction cascade must be located outside in a covered shed. Are you concerned about the potential for
operational problems? Why or why not? Use complete sentences and good grammar.
e) Consider the extraction process as a whole. Assuming you want to purify and sell the methanol as an inexpensive heating fuel, what general concerns might you have about the
proposed method? Is this a good idea, from a business standpoint? Why or why not?
How might you resolve any problems you noted?
No calculations or detailed analyses are required, but please justify your answer with
reference to physical properties, economics, or other practical concerns. You may
assume that there is a considerable demand for the fuel product.
