2 replies to this topic

[lanzpete]

Hi everyone Im an undergraduate petroleum engineering student. As one of our projects, weve been tasked to design an absorption tower for H2S removal. I was given the basis of Vented gases containing 35% H2S flow at a combined flow rate of 60 m3/ hr at temperature of 60°C and 1 ATM pressure. The tower needs to reduce the concentration of H2S gas to less than 7 ppm prior to discharge to atmosphere

 

I was thinking of using Monoethanolamine for the absorbent. however i cant find any equilibrium data that might help me get started. Im also at a loss at how to deal with absorption processes with chem reactions. can i treat this like any other physical absorption? Also this is a non dilute problem and i need to reduce the conc of H2S to an insignificant level. Should I do a reflux to lower the inlet conc.?

 

If someone could point me to the right direction as to how to approach this design, Id really appreciate it. Thank you all. 

Edited by lanzpete, 14 September 2016 - 08:05 AM.

[Art Montemayor]

Lanzpete:

 

Who thought of using Monoethanolamine (MEA) to absorb H₂S?????

 

That has to be about the worse selection you could use for removing H₂S.  Haven't you done any research into MEA and its properties and ability to absorb acid gases (excepting H₂S)?   I strongly recommend you study the Unit Operation of Gas Purification by reading the book titled exactly as such and written by Arthur Kohl and Richard Nielsen.  You can obtain it through Amazon Books.

 

For your information, MEA will be severely poisoned by the H₂S and will degenerate in contact with it, forming side corrosive products.  What you suggest simply won't work.

 

Go to: http://www.merichem....Removal-Process

and similar Google sites for information on existing processes.

[lanzpete]

Art Montemayor,

 

Thank you for your reply.

 

I haven't really looked into the specific properties of an MEA solution and its reaction with H2S. A couple of nights ago, I just read Packed Tower Design and Applications: Random and Structured Packings by Ralph Strigle Jr. and in that book there is a section about amine systems in chemical absorption. It was mentioned there that monoethanolamine or diethanolamine were widely used as absorbents in commercial absorption processes involving the removal of acid gases including H2S. So I thought I'd start there.

 

And yes, I also read about the degeneration of mea with CO2 if I recall, but I never really considered how it would impact the design. I guess I still have a lot of reading to do. Thank you for the heads up and also, thank you for the reference.