In an industrial scale fixed bed reactor for syngas to methanol conversion, why is the single-pass conversion of CO very low (~15-20%), despite a high equilibrium conversion achievable thermodynamically?
It looks like commercial units go fairly close to equilibrium limits to me. Temperature is relatively low to avoid undesirable side reactions. Here's info from Johnson-Mathey and Lurgi that might help.
Do you mean low-pressure methanol synthesis on copper catalysts (with additives) or old high-pressure one. Currently, the substrate is not only hydrogen and CO, but also CO2. Many factors influence the conversion degree. The reaction is exothermic. Too high temperature is not conducive to large conversion. In order to prevent too rapid temperature increase, the process is carried out at low conversion. Regards,
Prof. Rick Manner and Mirosław Grzesik
Dear Sirs, Sincere thanks for your responses. The documents and the explanation has been helpful.
To elaborate by doubt in detail:
The case I have mentioned refers to the low pressure Cu-based catalysts (e.g. Cu/Zn/Alumina).
If we use a multi-tubular (fixed-bed) reactor so as to maintain the reaction fluid at the optimal temperature (isothermal), is it not possible to attain conversion values near to the equilibrium conversion?
OR, is it not possible to make the system truly/ nearly isothermal thus limiting the conversion?
This is the conundrum I am being confused by.
Thank you!
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