I am considering using calcium carbonate to remove sulphides in the trickle bed reactor, and CaCO3 would be in the form of limestone granules and packed in a column above the condenser.
Questions:
1. Do you think CaCO3 would remove sulphides in the trickle bed reactor?
2. Is the reaction between CaCO3 and H2S exothermic? (i.e. should I worry about heat generation?)
3. Are there any risks associated with the facts that those will also be hydrogen and Am I assume methane in the exhaust too- for example, will CaCO3 react with H2 to form Ca(HCO3)2 and what would that cause to happen?
4. Are there any other risks that would happened with this procedure?
First some questions: What are the sulfides, and what are their concentrations? Are you talking about removing sulfides from oil? Will external hydrogen be supplied?
A possible problem with this idea is: if there is a reaction under your process conditions, it will be a stoichiometric acid/base reaction, not a catalytic reaction. Ca compounds do not catalyze hydrodesulfirization (HDS). Trickle-bed kinetics will not apply, certainly not for very long. Over time, the stoichiometric reaction(s) will weaken the CaCO3, even if it starts out as hard limestone. So depending on your feedstock, the bed will collapse and/or become plugged. In either case, flow would be blocked.
Water generated by the acid/base reaction will be big problem. Depending on your reaction conditions, water will indeed "slake" the limestone, turning it into calcium bicarbonate with a major change in morphology. The Ca(HCO3)2 is very likely to turn into powder. If R-SH is H2S, your chemical reaction network would be:
CaCO3 + H2S => Ca(SH)2 + H2CO3
H2CO3 => H2O + CO2
CaCO3 => Ca(HCO3)2
Dear Dr. Robinson,
Thank for your general explanation of the problem I am facing in my research work.
Would you please assist for the precisely articles which is explain the similar problem which is related to my work?
I would appreciate for that. I look forward to hearing from you.
Kind regards,
Peter Mponzi
Limestone granules will not effectively scrub hydrogen sulfide in a trickle bed reactor. Granular iron oxide, hematite typically more reactive than magnetite, is commonly and reasonably economically used to remove H2S, forming a mixture of ferrous sulfide and sulfur.
Peter,
H2 does not react with Limestone. The heat production should not worry you.
Dear Dr. Musterle,
1. In my reactor I have H2S which is emiited on the top of the reactor.
2 No, CO2 does not disturb in my reactor
3. My target temperature is 350C with 40 bar of hydrogen gase in the reactor
4. I am using Al2O3 support catalyst
Absolutely, hydrogen does not react with limestone.
Thank you for your questions, I look forward to hearing from you.
Kind regards,
Peter Mponzi
Peter,
Rod's suggestion is very good for your problem. May be a bit of iron granulate may support the desulphurisation. Iron and iron ions in hematite are fixing sulfur better than limestone.
Maybe this paper can also be helpfull: Ruiz-Agudo, E., Putnis, C. V., Hövelmann, J., Álvarez-Lloret, P., Ibáñez-Velasco, a., & Putnis, a. (2015). Experimental study of the replacement of calcite by calcium sulphates. Geochimica et Cosmochimica Acta, 156, 75–93. http://doi.org/10.1016/j.gca.2015.02.012
Good luck.
Dear Dr. Pedrosa,
Thank you for your hints corespondingt to the articles. Unfortunately, I do not have accesss to the Journals of Science Direct.
If you would have an access, would please help for sending article in the pDh format?
Thank you,
Peter Mponzi