Computer simulation applied to studying continuous spirit distillation and product quality control

Abstract

a b s t r a c tThis work aims to study continuous spirit distillation by computational simulation, presenting some strategies of process control to regulate the volatile content. The commercial simulator Aspen (Plus and dynamics) was selected. A standard solution containing ethanol, water and 10 minor components represented the wine to be distilled. A careful investigation of the vaporeliquid equilibrium was performed for the simulation of two different industrial plants. The simulation procedure was validated against experimental results collected from an industrial plant for bioethanol distillation. The simulations were conducted with and without the presence of a degassing system, in order to evaluate the efficiency of this system in the control of the volatile content. To improve the efficiency of the degassing system, a control loop based on a feedback controller was developed. The results showed that reflux ratio and product flow rate have an important influence on the spirit composition. High reflux ratios and spirit flow rates allow for better control of spirit contamination. As an alternative to control the volatile contents, the degassing system was highly efficient in the case of low contamination. For a wine with high volatile contamination, the pasteurized spirit distillation unit was the best alternative.

Batch distillation of spirits: experimental study and simulation of the behaviour of volatile aroma compounds

“…In parallel to this experimental approach, many researchers have used simulation to explore the behaviour of the volatile compounds and the influence of the operating parameters on distillation. Many studies have been published on continuous distillation in multistage columns , batch distillation in columns or alembic . For batch distillation in alembic stills, Scanavini et al .…”

“… carried out a bibliographic review, gathering all available data on liquid–vapour equilibria for volatile compounds in hydro‐alcoholic solutions, covering 44 volatile compounds belonging to several chemical families (12 alcohols, 12 esters, nine carboxylic acids, one acetal, seven carbonyl compounds, one furan and two terpenes). The ‘Non Random Two Liquids’ (NRTL) model was selected to represent the non‐ideality of the solution , as advised by Batista and Meirelles and Valderrama et al . .…”

Influence of Fusel Oil Components on the Distillation of Hydrous Ethanol Fuel (Hef) in a Bench Column

“…The Lancet (The Lancet, 1901) reported: "It has intoxicating and poisonous properties superior to those of ordinary spirits, and is said to be known in some of the northern counties of Europe to the consumers of corn brandy who frequently ask to be served with a 'glass of good fusel'." The compounds 3-methyl-1-butanol, butan-1-ol, propan-1-ol and propan-2-ol are primarily responsible for the aroma of distilled spirits (Batista and Meirelles, 2011;Scanavini et al, 2012), but high concentrations of these compounds can cause health problems (Opdyke, 1978;Lachenmeier et al, 2008).…”

“…Two to 6.5% of the total feed ethanol must be purged to remove fusel oil from the distillate (neutral distillate) (Valderrama et al, 2012). Batista and Meirelles (2011) reported that, in the distillation of drinking ethanol, the higher alcohols become more concentrated in the distillate at low distillate flow rates and low reflux ratios. The equilibrium curve of the ethanol/water/3-methyl-1-butanol system at a temperature of 25 °C shows that there is a wide concentration range over which two phases co-exist in the system, which can be used to separate and remove 3-methyl-1-butanol (Kadir et al 2008).…”

“…Brau (1957) reported fusel oil contents between 0.1 and 1.1%. Table 2 shows the average composition for fermented sugarcane juice, as given by Batista and Meirelles (2011).…”