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Abstract: With the study object of an 100kt/a SL-II ethylene cracking furnace, this paper used Computational Fluid Dynamics (CFD) method to carry out coupled simulation studies on the flow, combustion, radiative heat transfer and thermal cracking reaction processes in the cracking furnace. The standard k–ε two-equation model was applied to turbulence simulation. The finite-rate/eddy-dissipation model was used for modeling of non-premixed combustion of the bottom burners and premixed combustion of the sidewall burners. The Discrete Ordinates (DO) model was applied to the simulation of radiative heat transfer of furnace. The simulation results show the detailed information about velocity, temperature and concentration fields in the furnace and heat flux distribution on the reactor tubes skin. This work will provide a theoretical basis for the optimization of the geometrical structure and operational parameters of the cracking furnace. [Copyright &y& Elsevier]

This paper presents a mathematical model based on a three-phase theory, which is used to describe the mass and heat transfer between the gas and solids phases in a batch fluidised bed dryer. In the model, it is assumed that the dilute phase (i.e., bubble) is plug flow while the interstitial gas and the solid particles are considered as being perfectly mixed. The thermal conductivity of wet particles is modelled using a serial and parallel circuit. The moisture diffusion in wet particles was simulated using a numerical finite volume method. Applying a simplified lumped model to a single solid particle, the heat and mass transfer between the interstitial gas and solid phase is taken into account during the whole drying process as three drying rate periods: warming-up, constant rate and falling-rate. The effects of the process parameters, such as particle size, gas velocity, inlet gas temperature and relative humidity, on the moisture content of solids in the bed have been studied by numerical computation using this model. The results are in good agreement with experimental data of heat and mass transfer in fluidised bed dryers. The model will be employed for online simulation of a fluidised bed dryer and for online control. [Copyright &y& Elsevier]