In a Koppers-Totzek reactor, why do I get CO and H₂ instead of CO₂ and H₂O?
The reaction occurs in two stages: in first $\ce{C}$ oxidized to $\ce{CO2}$ and then $\ce{CO2}$ is reduced to $\ce{CO}$.

The process of having carbon react with oxygen and water vapor is called steam-oxygen conversion. It is used, because in reality, due to the high reaction temperatures, the allothermic principle is hard to provide.

$$\ce{C + O2-&gt;CO2}$$
$$\ce{C + 2H2O-&gt;CO2 + 2H2}$$
$$\ce{C + H2O-&gt;CO2 + H2}$$
$$\ce{C + CO2-&gt;2CO}$$

The equilibrium concentrations of $\ce{O2}$ and $\ce{H2O}$ in the gasification products at all temperatures are negligible. Steam-oxygen gasification products are a mixture of $\ce{CO2}$, $\ce{CO}$ and $\ce{H2}$.

Before carrying out the reaction of the shift
$$\ce{CO + H2O-&gt;CO2 + H2}$$ from a mixture of $\ce{CO2}$, $\ce{CO}$ and $\ce{H2}$ must be separated $\ce{CO2}$. To this must be expended work division (again burn some $\ce{C}$).