Development of Anhydrous Ethanol Purification: Reduction of Acetal Content and Vapor–Liquid Equilibrium Study of the Ethanol–Acetal Binary System

Abstract

Acetaldehyde diethyl acetal (herein called acetal) is an important pollutant of anhydrous ethanol. Isobaric vapor−liquid equilibrium (VLE) of an ethanol−acetal binary system was measured using a vapor condensate and liquid circulation VLE still. The experimental data were correlated with Wilson, nonrandom twoliquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models, which were found suitable for representing the VLE data. Proper agreements between experimental and calculated VLE data were obtained, which were then confirmed with consistency tests. The applicability of the novel VLE data was demonstrated during an investigation of an anhydrous ethanol purification column. Reduction of the concentration of acetal and other pollutants was examined and optimized in a flowsheet environment. The modeling results were verified in a laboratory with an experimental distillation column, confirming a correct agreement between the results. It must be highlighted that the developed method is suitable for the production of pharmacopeial quality anhydrous alcohol, based on reliable, verified VLE data. The results show the importance of accurate VLE data in critical compositions (low pollutant content); moreover, aiming at high product purity, experimental validation has paramount importance. The consistency between the three platforms (VLE and distillation experiments and flowsheet simulation) confirms the accuracy of the developed method.

Vapor–Liquid Equilibrium Study of the Monochlorobenzene–4,6-Dichloropyrimidine Binary System

“… 32 D H and J H values are calculated according to the following equations. 17 The D H value was 0.37% and the J H value was found to be 7.60%; therefore, D H – J H is 7.2%. It can be stated that the measured values are consistent and match with the literature data; therefore, our experimental setup can also provide accurate and reproducible data describing the isobaric vapor–liquid equilibrium of monochlorobenzene (1)–4,6-dichloropyrimidine (2) at P = 101 kPa.…”

“…The measured VLE data of the acetal–ethanol and acetaldehyde–ethanol binary mixtures are consistent too. 17 …”

“…The vapor–liquid equilibrium experiments were achieved with a modified Gillespie apparatus. 17 Duplicated sampler walls on the unit were applied to establish external cooling to decrease casual evaporation of the components from the liquid and vapor samples. Powerful mixing of the samples was achieved by magnetic stirrers in both sampler parts.…”

Compliance with hand sanitizer quality during the SARS-CoV-2 pandemic: Assessing the impurities in an ethanol plant

“…Double distillation produced fractions with lower impurities concentration ( Balcerek et al, 2017 ). Acetal was correctly calculated and the fractions removed were accurately estimated in columns ( Haaz et al, 2021 ). Unfortunately, this would increase the operating costs and natural gas use, and it would also require capital costs for the construction and instillation of the column.…”

Multi-objective Optimization and Control of Self-Heat Recuperative Azeoropic Distillation for Separating an Ethanol/Water Mixture

“…Bioethanol is a promising alternative energy source in the short and medium term. 1 In addition, bioethanol is easier to mix with gasoline than with other alternative fuels. The dehydration process is one of the key technologies in ethanol production since the ethanol content obtained from biomass production is low.…”