green monster question, page-6

Sandminer,

unfortunately this recycling of CO2 can't work. The reason is that its endothermic so you need energy to make it work, thus you need to add more oxygen, which defats the purpose. In the end you have the following reactions:

C + O2 -> CO2 (exothermic)
C + CO2 -> 2CO (endothermic)

which overall gives us back

2C + O2 -> 2CO (exothermic)

or equivalently

C + 1/2 O2 -> CO

So there's no benefit. In fact as the recyling of CO2 consumes energy we will lose efficiency by doing this.

Using the CO2 as an inert to control temperatures is in principle feasible, but I think there are better ways. Steam for example is plentiful in the underground gasifier and can normally be controlled via managing the pressure of the process.