Separation of the benzene/cyclohexane mixture by stripping crystallization

Stripping crystallization (SC), also called distillative freezing (DF), is introduced to separate the benzene (Bz)/cyclohexane (Cx) mixture. In principle, SC is operated at a triple-point condition, in which the liquid mixture is simultaneously vaporized and crystallized due to the three-phase equilibrium. Thus, SC combines distillation and crystallization to produce pure crystals. The experiments show that three SC operations are required to purify Cx (B) from X-W,X-B = 0.907 to X-W,X-B = 0.996 in the Cx-rich mixture. On the other hand, only one SC operation is required to purify Bz (A) mixture from X-W,X-A = 0.893 to X-W,X-A = 0.999 in the Bz-rich mixture. Thus, it is easier to separate Bz from the Bz-rich mixture than to separate Cx from the Cx-rich mixture. These experimental results are consistent with the simulations predicted by the proposed model. (C) 2008 Elsevier B.V. All rights reserved.