Distillieries - Environmental Clearance

1.1.2 Weak wash recyclingThe recycling of weak wash helps maintain the desired level of dissolved solids inthe fermenter, so that an adequately high osmotic pressure is achieved.Osmotic pressure and the concentration of alcohol in the fermenter, together keep offinfection and minimize sugar losses. Weak wash recycling also reduces the quantityof effluent spent wash and reduces the process water requirement of the plant.Normally this is taken from the 5th plate of the Analyzer Column.Spent wash is the wash from which all alcohol has been removed, this emerges fromthe bottom of the wash column. Some of the heat is recovered to preheat fermentedwash entering the de-gassifying column. Spent wash is also passed through a forcedcirculation re-boiler to generate vapours. This concentrates the effluent and reducesthe volume further. The Spent Wash volume generated can be in the range of 6-8Ltrs/ Ltr of Alcohol produced depending on the FS/ NFS ratio of the feed Molasses.1.1.3 PropagationThe propagation section is a feeder unit to the fermenter. Schizosaccharomyeespombe Yeast is used. This is grown in 3 stages. The first two stages are designed foraseptic growth. Propagation vessel III, develops the inocculum using pasteurizedmolasses solution as the medium. This vessel has a dual function. Duringpropagation, it serves for inocculum build-up. When the fermenter enters thecontinuous production mode, Propagation Vessel III is used as an intermediate washtank. Propagation is carried out only to start up the process initially or after very longshut-downs during which the fermenter is emptied.1.2 Distillation sectionDistillation section is designed with multi pressure vacuum distillation technique toproduce Rectified spirit. The system designed is integrated for minimum steamconsumption while producing Rectified Spirit directly from the fermented wash. Thesystem comprises of Wash-cum-Degassifier Column with Rectifier Column, &Heads Column.The clarified wash after heating in wash heater by over head vapours from washcolumn is further heated in spent wash heater is fed to degassifying section ofcolumn. The vapours from wash column are partially condensed in a beer heatercondenser for recovery of heat & non-condensed vapours are condensed in the finalcondenser. The beer/ wash column is operated under vacuum and designed with sievetrays. The design of wash column enables operation of the column continuously forlonger durations ( minimum 180 days without opening for cleaning ). The energy tobeer column is provided by re-boiler located at the bottom of column and heated byover head vapours from rectifier column.The raw spirit approx. 40% w/w is sent to intermediate raw spirit tank. Raw Spirit isthen fed to stripper rectifier column for removing high volatile impurities. Fusel oilsare tapped from appropriate trays and separated in fusel oil decanter after cooling infusel oil cooler. The rectifier column is designed to operate under pressure with Sieveii