2 replies to this topic

[mbeychok]

Ahboon:

This is not a direct answer to your questions, but I think you may find some useful information at this web site:

www.synetix.com/refineries/pdfs/manuals/700W.pdf

[Art Montemayor]

Ahboon:

Milton Beychok's website recommendation is just the ticket you needed to learn further points about the methanation process.

I suspect that you are having a problem debating about an isothermal reactor for the methanation step because of your misunderstanding of what an adiabatic reactor does and how it works. Your comments seem to indicate that you expect an accumulation of heat in an adiabatic reactor. This is not what happens. The high exothermic heat generated by the reactants is carried out by the products that are exiting under a steady state. This is NOT a batch reactor where the products remain in the vessel. Of course, there is an increase in operating temperature in accordance with the stabilized temperature reached due to the reaction. The higher the amount of reactant CO & CO2, the higher the ultimate stabilized temperature in the reactor. The Nickel catalyst is a rugged catalyst and can take the high temperature operation.

Believe me, you are wasting your time debating about using an isothermal reactor. There is no need to use multiple catalyst beds. This is a once-in-once-out process where the reaction essentially goes to completion with the excess amount of H2 present. The space velocity is used to design the size of the vessel - as you should know from your theory lectures.

Without trying to belittle your effort, I believe you should know that this Methanator design is probably the easiest design in an Ammonia process plant. You don't have to worry about multi-beds, intercoolers, catalyst regeneration, elaborate temperature controls, side streams, etc. The catalyst just sits there and works - period.

Good luck on putting your design together.