A Koppers-Totzek reactor (there seems to be only a German Wikipedia page) is an entrained flow gasifier that blows coal dust, oxygen and water (as steam, of course) into a burning chamber where the coal burns at about 1600 °C. The output contains around 60% $\ce{CO}$ and 33% $\ce{H2}$, plus some $\ce{CO2}$ and (very little) $\ce{CH4}$.
When burning coal, I would expect $\ce{CO2}$ and $\ce{H2O}$ as output, is the reactor simply providing too little oxygen, or is there something about the process that produces the output observed?