As a promising clean coal technology, co-gasification has been extensively investigated. In this paper, a new co-gasification technology and a conceptually designed gasifier for such technology are proposed. The distinct advantages of this technology are its fuel flexibility and the availability to establish the gasifier by reconstructing a blast furnace or similar shaft furnace. Based on the idea of the new co-gasification technology, process modeling is conducted using the ASPEN Plus process simulator. By comparison with the laboratory scale experimental measurements on the co-gasification process, it is shown that the developed model reasonably describes the thermodynamic features of the co-gasification process and, thus, provides a useful tool for the analysis of this process. The obtained results also demonstrate that the cogasification process provides an ideal thermodynamic condition for the co-gasification reactions and can operate at a quasi-equilibrium condition without employing catalysts at 1273 K. Lastly, the effects of changes of oxygen, steam and natural gas in the feedstock on the co-gasification process are studied by sensitivity analysis using the developed model. (c) 2005 Elsevier Ltd. All rights reserved.