Résumé:
The objectif of this project was about producing ethanol from cane molasses by alcoholic fermentation. Physical and chemical analysis were performed in order to evaluate the quality of molasses and its sugar content. Fermentation tests were also implemented to obtain a good yield of ethanol. The first as well as the second were used to see the effect of the absence of urea and the determination of the optimal dose for the urea requirement, for this, different amounts of urea were added to the must at a percentage of 30%, 50% and 100% in relation to the amount of yeast. The third consisted in defining the optimal quantity of baker's yeast to be added, between 0.71%, 1.42% and 2.84% relative to the quantity of sugars present in the must. As for the last test, its goal was to try to find the best sugar concentration between 10, 20, 25 and 30% of the total volume of the fermentation must. The pH was adjusted to 4.8 using 96% sulfuric acid and the fermentation was conducted for 72 hours at a temperature of 30 ° C. The study indicated that the best yield of ethanol is 13.5% which can be obtained when the must of fermentation includes 50% of urea, 1.42% of baker's yeast,25% of sugar concentration.
