I am trying to model some industrial processes and having a hard time finding information about the Sabatier reaction. The Sabatier reaction combines $\ce{CO2}$ (and possibly $\ce{CO}$) with $\ce{H2}$ to produce $\ce{H2O}$ and $\ce{CH4}$.
On the one hand, this reaction is exothermic. On the other hand, it requires high heat and pressure. Does the reactor need initial heating and pressurizing of the gases, and then is it self-sustaining (or rather requiring cooling)?
What is clear is that some energy is be needed to compress gases and flow them over the catalysts.
Are there any estimates of how much energy a reactor would use? I understand that scale would also be an important parameter, but any preliminary estimates are useful to me.