A theoretical consideration is given to a four-staged gasification process, using a numerical model. The process employs recirculation of hot flue gases. This is to lessen the sensitivity of the process to variation of reaction parameters. The chemical efficiency, i.e. the ratio of product gas caloricity to the caloricity of initial solid fuel, is analysed for different cases, including partial load modes. The ability of the process to follow the load curve is discussed. The most attractive modes of gasification are shown to reside on the brink of inconvertible carbon formation. The conditions for the latter are predefined by heat losses.