Purification of m-xylene from the mixed xylenes by stripping crystallization

Stripping crystallization (SC) was applied in this work for purification of m-xylene (MX) from the mixed xylenes consisting of MX, p-xylene (PX), o-xylene (OX) and ethylbenzene (EB). As SC is operated in a series of three-phase transformations by decreasing temperature and reducing pressure, SC combines melt crystallization and vaporization to produce the MX crystalline product and mixture vapor from the liquid mixture. An apparatus was design to be operated from − 47.85 °C and 3.21Pa to -80°C and 0.04Pa. A model based on the thermodynamics coupled with the mass and energy balances was proposed to determine a series of three-phase transformation conditions, which were adopted to direct the SC experiments. The experimental purity and recovery ratio of MX in the final product were compared with the calculated results predicted by the model.