Heat Effects in Solid Reactions 1

[Jason42]

Hello fellow engineers, I have a somewhat confusing problem relating to heat effects in solid reactions.
The process is as follows: serpentine (Mg3Si2O5(OH)4) is to be thermally activated (dehydroxylation) in a fluidized bed reactor.
Within this process, combustion gases are used to fluidize a bed of serpentine minerals which are dehydroxylated to magnesia (MgO), silica (SiO2) and water. This reaction requires 131 kJ/mol.
I have all thermodynamic data available (specific heats, flow rates etc) and my goal is to find the final temperature of the dehydroxylated ore. However, I am currently stuck in solving this problem. My first guess is to solve this problem in a similar fashion that one would use in determining the adiabatic flame temperature. Would this be a smart approach? Or is there a better method?
Any help on this topic would be greatly appreciated.
Many Thanks,
Jason

 

[StoneCold]

I would use a material and energy balance if you have enough information. If you don't have enough info then you might have to use the flame temperature and make the assumption that the material is in the reactor long enough to reach equilibrium with the flue gas. But I think you will get closest if you know the amount of fuel used and the air ratio and try to attack the problem from the amount of heat added to the system.

Regards

StoneCold

 

[Jason42]

Thanks StoneCold. Yeah I have already determined the adiabated flame temperature of the combustion gas, thus I know the temperature of my fluidising medium. It would be a nice idea to allow thermal equilibrium but I can't over heat the materiel as sintering will occur (unwanted due to further downstream opps). Thank you for the quick reply though. Much appreciated.