I can’t understand the answers to the exercise set in the registered Chemical Industry Association version
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Dear sea friends: 1) In the solution to questions 5-28 on page P112 of the association version* of the question set, the solubility coefficient H is given as ρs/EMs. Regarding Ms=18 kg/kmol, this value isn’t specified in the original question; so why is it assumed that Ms=18 kg/kmol? The only value provided is the density of the liquid phase, which is 1000 kg/m3 – this seems a bit far-fetched. I hope Hero Haiyou can discuss this. 2) Still, in the solution for 5-30 on page P114 of this book: V/Ω≈0.024 kmol/㎡/s, which also seems a bit forced ； 3) In the solution to question 5-32 on page P116, it is given that X1 = 0.005/(1-0.005). However, the problem states that the molar fraction of aromatics in the washing oil entering the top of the absorption tower is 0.005; therefore, I believe it should be X2 = 0.005/(1-0.005), as this refers to the value at the tower top ； I’m not sure if I’ve misunderstood or if there’s an error in the book; I hope experienced sailors can discuss this with me. Thank you all!
This post was last edited by Higee on 2015-8-14 at 16:11. 1) The problem treats the absorbent as water directly. 2) The amount of inert components in the feed gas is approximately equal to the total gas flow rate; this is a common approximation used in the absorption of gases at low concentrations. The textbook on chemical engineering from Tianjin University states that this approach can be applied when the solute concentration in the feed gas is below 10%. 3) The answer given seems to refer to co-current absorption, but this is not specified in the problem, which is confusing. If it is countercurrent absorption, your understanding is correct
The first question seems to be related to water treatment
Where can I buy the registered chemical association version of the question set?
Summary post – Registered chemical engineering exam preparation materials: http://bbs.hcbbs.com/thread-1384852-1-1.html (Source: Haichuan Chemical Engineering Forum)