Vapour – liquid equilibria of acetic acid + water and propanoic acid + water: experimental measurement and thermodynamic modelling

[摘要] Vapour – liquid equilibria were measured for the acetic acid + water and the propanoic acid + water systems, in the temperature range of 412.6 to 483.2 K and pressures of 1.87 to 19.38 bar, over the entire range of concentrations. An experimental apparatus based on the static-analytical method with sampling of both phases was used with quantitative analysis by GC. A new experimental technique comprising positron emission particle tracking (PEPT) was developed and applied for the determination phase compositions and molar volumes for the acetic acid + water system at 412.6 K.The Peng-Robinson (PR), the Cubic Plus Association (CPA), the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) and the PC-polar-SAFT (PCP-SAFT) equations modelled the data. The 1A and 2B association schemes for propanoic acid and the 2B, 3B and 4C for water, were evaluated. In CPA, the ECR and CR1 combining rules were also tested. A single binary interaction parameter was used in all models. PCP-SAFT presented higher predictive and correlative capabilities when the organic acid was modelled as 1A and water as 2B. The best association combination among CPA and PC-SAFT was 2B and 4C for the acid and water, respectively. CR1 accounted for lower errors in predictive mode while ECR in correlative mode. CPA performance was intermediate between the PC-SAFT and PCP-SAFT models and the PR equation. PR predictions were rather poor but correlations were better than those of CPA, at the expense of a larger binary interaction parameter.

[发布机构] University:University of Birmingham;Department:School of Chemical Engineering

[关键词] T Technology;TP Chemical technology