| Popis: |
A non-isothermal model was developed for gasification of a single char particle in an environment of a gas mixture commonly occurring in moving bed reactors. The model, describing the heterogeneous reactions between gases and a porous char particle, was based on the consideration of simultaneous energy and mass conservation principles with changing physical properties as reactions proceed. The model solving process utilized the Fredholm integral technique, converting the resultant differential equations into non-linear algebraic equation systems. Results from the model indicated that the intra-particle gradients of gas concentrations, temperature and carbon conversion profiles became more pronounced as the particle size and/or the bulk fluid temperature increased, due to the effect of diffusional limitations. The carbon conversion is volumetric, having a higher fractional conversion at the particle surface and decreasing towards the center during the gasification process. |
