The project aims at improving the efficiency of the conversion step in the fuel chain, to expand the raw material base with ash-rich fuels. A previously defined conceptual ash-transformation model will be developed further by adapting it to specific incinerators. In parallel and in close cooperation, opportunities to implement this "adapted" model in an MPC (Nonlinear-Model Predictive-Control) will be explored. With such a model, the plant can be controlled more efficiently, which will be necessary for the increased demand for fuel flexibility associated with difficult ash-rich fuels. The novelty lies in that basic research on control theory and complex ash-transformation for the first time will be integrated and implemented for the control of combustion plants. The project is part of a larger Sweden-China collaboration titled "To develop high energy efficiency and small-scale bioenergy combine in Jilin: Innovation and Demonstration"