Numerical model to simulate wax crystallization in: Scraped surface heat exchangers

This paper presents a numerical model describe the kinetic of wax crystallization in scraped surface exchangers that mostly used in solvent dewaxing as a separation technique. The model consists of a combination between the heat transfer and the kinetic of wax crystallization. Solvent dewaxing process is selectivity reduced the higher normal paraffin components. This fact provides easier handling of the characteristic of the kinetics of wax crystallization, physical properties, and flow behavior. Chemical analyses of the feedstock are important to specify the carbon number distribution, dissolved temperature, and wax content. Wax crystallization in scraped surface heat exchanger is dependent of a large number of variables and is still subject of unclassified researches within few companies. Such process as affected by multi-parameters, need a mathematical description of wax crystallization to predict e.g. the mass fraction, the crystals number, their size, and temperature distribution incrementally. Controlling of the solvent injection ratio is very important parameter e.g. to adjust the viscosity and supersaturation of the oil-solvent-wax mixture. The simulation results will satisfy the wax crystals characteristics and oil recovery.