ATTAINABLE REGIONS FOR REACTION WITH SEPARATION

The attainable region approach for reaction-mixing systems is combined with geometric methods for the feasibility of separations The result is a systematic approach to identify the feasible compositions that ca n be achieved in processes combining simultaneous reaction mixing, and separation. An activity-based formulation for both nonideal VLE and r eaction-rate expressions is applied to develop hybrid reactor-separato r models for the multiphase CSTR and PFR with simultaneous vapor remov al A reaction-separation vector is defined that satisfies the same geo metric properties as the reaction vector Therefore, the attainable reg ion can be constructed following the existing procedure for reaction-m ixing systems. This approach provides a method to generate feasible pr ocess alternatives. The technique is demonstrated on two nonideal tern ary mixtures: the production of dimethyl ether by dehydration of metha nol and the production of methyl tert-butyl ether from isobutene and m ethanol. It is shown that for hybrid reaction-separation devices the e ntire composition space is not always attainable. In such cases, combi ning a hybrid device with traditional nonreactive separations is requi red to attain certain products.