Ethanol purification

Optimisation of a Bio-ethanol Purification Process Using Conceptual Design and Simulation Tools... 

Once an initial design of the purification plant is obtained, opportunities of improvement are easily recognized and then tested by performing the design and simulation steps until a cost-effective bio-ethanol purification plant is achieved. 

Keywords Bio-ethanol Purification Plant, Evolutionary Optimisation, Conceptual Design, Rigorous Simulation. 

Optimisation of both design and operation variables of a bio-ethanol purification plant intended to produce fuel grade ethanol is a challenge to make the bio-fuel a realistic alternative in the energy market. 

Experiments were attempted with both ethanol and manganous ion present. The results conformed to no simple rate law and seemed only understandable if it was assumed that the manganous ion (at <4 x 10-1 M) was being complexed by an impurity in the ethanol. Purification of the ethanol by distillation increased the rate a. 4 fold but did not eliminate the effect. Because of the apparent participation of the buffer in the rate law, work on buffered systems was discontinued. 

We are continuing more detailed studies on the use of polymer-bound borohydrides for solvent and ethanol purification. 

The membranes used for ethanol purification are also suitable for dehydration of many other organic solvents, including methanol, isopropanol, butanol, methyl ethyl ketone, acetone, and chlorinated solvents. Commercial units use up to 12 stages with reheating between stages, and product water contents lower than 100 ppm can be obtained. 

Example 4.10 Sieve-Tray Distillation Column for Ethanol Purification... 

The first commercial application of PV was for ethanol purification. The dilute ethanol solution produced by fermentation is distilled to produce an overhead product with 90 to 95 wt% alcohol (close to the azeotrope). This solution is fed to the PV unit where water is selectively removed to give nearly pure ethanol (99.9 wt%). The permeate stream, with about 20 to 40 wt% alcohol is recycled to the distillation column. 

H]W1N55,212-2. A solution of 25 mg (0.044 mmol) of precursor 56 in 2 mL of ethanol with 25 mg of 10% Pd/C and 0.025 mL of triethylamine was vigorously stirred with 80 Ci of tritium gas at ambient temperature and atmospheric pressure for 4 h. After this time the catalyst was filtered, labile tritium was ronoved by several evaporations of methanol, and the crude product (1960 mCi) was dissolved in 20 mL of ethanol. Purification was accomplished on two 500-mm silica gel plates eluted with hexaneiethyl acetate 50 50 to afford 988 mCi (a 37% radiochemical yield based on precursor 56) of product that was found to be >98% radiochemically pure and to coelute with authentic WIN55,212-2 (49) both on silica gel TLC (hexane ethyl acetate 50 50) and reverse-phase HPLC (water acetonitrile 35 65). The specific activity of product [ H]WIN55,212-2 was measured to be 60 Ci/mmol by UV assay (where E246 = 20,958) and the UV of product was superimposable on that of unlabeled compound. A proton-decoupled tritium NMR (CDCI3) of product 49 showed two peaks at 7.49 and 7.98 ppm. 

M sucrose, 0.05 mM Na2EDTA, and 1 mM ethanol. Purification of torpedo electroplax membranes were also carried out, and the separation of various bacterial cells were also described, including the purification of different strains of Escherichia coli and the separation of Salmonella typhirum cells, using PEG-dextran ATPS systems. Moreover, these CCC devices were also applied to larger cells, such as the separation of various species of red blood cells. 

Figure 11.4 Ethanol purification via distillation coupled with pervaporation. Adapted from Huang, Baker, et al. (2010). 

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