Particulate systems and separation processes, Chemistry

i) Define a membrane in a process engineering context.

Two of the main desired attributes of membranes are high permeability and high selectivity. Define permeability and selectivity.

Explain why it is generally not possible to achieve both high permeability and high selectivity at the same time.

ii) Define a chromatography process and explain how the separation takes place.

Discuss briefly the separation mechanisms for the following two chromatographic processes:

i) Ion exchange chromatography

ii) Size exclusion chromatography

iii) Membranes are used extensively in air separation to produce oxygen and/or nitrogen. Consider a process which is to produce a product permeate stream qp of oxygen-enriched air in a single stage system. The process is to be carried out using a vacuum pump on the permeate side with an absolute total downstream pressure Pdown. The air flow rate qf is to be pumped into the membrane using a blower from an absolute total upstream pressure Pup.

A PDMS/tetraethoxysilicone hybrid membrane is considered for the separation. At 30 °C and a pressure difference of 0.08 MPa, the oxygen permeability coefficient and the ideal separation factor were found to be 370 Barrer and 3.45, respectively.

a) For the hybrid membrane, what is the maximum achievable permeate concentration of oxygen xp,O2?

b) Assume a membrane thickness of Δx = 1 μm. Find the permeability coefficient PO2 of oxygen through the membrane in m3 m-2 hr-1 atm-1.

c) What is the flux of oxygen JO2 through the membrane in m3m-2hr-1 when the upstream pressure Pup is 1 atm and the pressure difference across the membrane is 0.08 MPa? (If you were not able to find the permeability coefficient PO2 above, use a value of 1x10-5m3 m-2hr-1atm-1 but please note that this is not the value sought.)

d) The membrane unit is to consist of 4 identical membrane modules in parallel of 25 m2 per module. What is the maximum achievable permeate flow rate of oxygen qp,O2 for the unit in m3hr-1?

e) Would you expect to be able to achieve this permeate flow rate at all times and why/why not?

Posted Date: 3/20/2013 5:31:10 AM | Location : United States







Related Discussions:- Particulate systems and separation processes, Assignment Help, Ask Question on Particulate systems and separation processes, Get Answer, Expert's Help, Particulate systems and separation processes Discussions

Write discussion on Particulate systems and separation processes
Your posts are moderated
Related Questions
Calculate ionisation potential of the electron in the first exited state of singly ionised Helium atom is given by ionisation of Hydrogen atom to be 13.6 eV. Ans: According to

Q. Storehouse of minerals? in addition to the earth's crust, oceans also provide a huge storehouse of minerals in which the metals occur primarily as soluble sulphates and hali

5H is the most stable, and the least stable isotope is 7H

The intramolecular product tetrahydrofuran results from an internal nucleophilic substitution reaction of the alkoxide on the alkyl halide. The intermolecular product 1,4-butanedio

chemical properties of protium,deuterium and tritium..

Q. Calculate the specific heat of strange metal? Ans. You found a 50.0 sample of an unknown metal while you were scuba diving near the remains of anancient ship wreck. To test

Which of the following is not true in Rutherford's nuclear model of atom: (1) Protons and neutrons are present inside nucleus (2) Volume of nucleus is very small as compared

what is silver silver electrode

The number of electrons in the nucleus of C 12   is (1) 6        (2) 12       (3)0      (4)3 Ans: 0

Which geometry does have Formaldehyde molecule The formaldehyde molecule has trigonal planar geometry. Therefore, both the H-C-H bond angle and the H-CAO bond angle are abou