Batch distillation of nonideal mixtures usually produces the azeotropes often associated with those mixtures. Among various techniques available to break azeotropes, azeotropic and extractive distillation processes have a place of choice. They rely upon the selection of a suitable entrainer. Entrainer screening is therefore a key step for the synthesis and design of these processes. From an analysis of all ternary residue curve maps under assumptions of a large number of stages and total reflux/reboil ratio, we devise in this paper a complete set of rules for the selection of a suitable entrainer enabling the separation of minimum-and maximum-boiling azeotropic binary mixtures and close-boiling-temperature binary mixtures. These rules complete previously published rules and expand by many times the set of entrainer alternatives previously considered. Feasible batch distillation processes can always be obtained considering two batch task sequences using rectifier and stripper configurations. The effect of distillation boundary curvature on the selection of entrainers is analyzed, and in this case, a sequence of up to a three batch distillation configurations must be used to separate the original mixture components.Several practical examples are shown to illustrate the application of the defined rules in each studied case.
<p style="text-align: justify;"><strong>Aims</strong>: Inhibition of potassium hydrogen tartrate (KHT) crystallization by carboxymethylcellulose (CMC) is tested in a model solution and in wines. Tartaric acid salt crystallization risk is assessed by computing the supersaturation, saturation temperature and excess KHT with respect to the saturation equilibrium using MEXTAR® (Mesure de l’EXces de TARtre) software.</p><p style="text-align: justify;"><strong>Materials and results</strong>: Firstly, the time for crystals to appear was recorded by monitoring the conductivity in a model solution and in a wine, and the inhibition ratio was computed. At 11,5 °C, 0,5 mg.L<sup>-1</sup> CMC inhibited KHT crystallization. The inhibitory effect increased exponentially with increasing CMC concentration and was several times greater than that of polysaccharides and polyphenols, the protective colloids in wine (Gerbaud et al., 1997). At 2 °C, 30 mg.L<sup>-1</sup> CMC had the same inhibitory effect than 10 mg.L<sup>-1</sup> at 11.5°C.Secondly, 20 red and white wines were refrigerated for 3 weeks at -4 °C with CMC or metatartaric acid. Results show that the addition of 20 mg.L<sup>-1</sup> CMC has an inhibitory effect at least equivalent to 100 mg.L<sup>-1</sup> metatartaric acid. Furthermore, for 10 wines preheated for 8 days at 30 °C and then refrigerated for 2 months at 0 °C, 5 and 20 mg. L<sup>-1</sup> CMC maintains its inhibitory efficiency, unlike metatartaric acid which is hydrolysed</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The OIV-OENO 366-2009 and OIV-OENO 02/2008 resolutions recently authorized the use of CMC to prevent tartaric acid salt precipitation. With no impact on health, and stable under heating and in acid solution, CMC is an efficient candidate for tartaric stabilization. The optimal concentration of 20 mg.L<sup>-1</sup> (2 g.hL<sup>-1</sup>) should however be adapted to local wine storage conditions and KHT crystallization risk.</p>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.