Numerical modelling of sorption-enhanced gasification: Development of a fuel decomposition model

Sorption-enhanced gasification (SEG) is a promising technology for producing renewable feedstock gas to be used in biofuel synthesis processes, especially in dimethyl ether (DME) synthesis. To adopt the technology on a commercial scale, it is necessary to acquire knowledge about the related operational characteristics. The SEG process is carried out at lower temperatures than those employed in conventional gasifiers. A typical operating range is from 600 degrees C to 800 degrees C. Fuel decomposition experiments have shown distribution of the decomposition products to vary by the process temperature in this operating range, and thus, it is important to adapt this phenomenon for modelling the SEG process. To model the temperature dependence of the decomposition products, a fuel model was developed. Fuel decomposition experiments were conducted to obtain the boundary conditions for the fuel model. The developed fuel model was implemented to an SEG model frame, and the model prediction was compared against data from a 200 kWth dual fluidised bed facility. The model gave satisfactory predictions for producer composition and temperature trends. Furthermore, the main balances of the model were in agreement with typical trends of the SEG process. The conducted simulations improved our understanding of material balances in SEG reactors. Knowledge from physical operations governing the process is of value in further development of the technology.