In the process of distillation vapors passing through the condenser tube are cooled and condensed by water flowing through condenser tube in the condenser unit of the apparatus. In almost all laboratories the water used for cooling the condenser tube is coming from the water supply tap near the wash basin. The precious water after circulating through the condenser tube is left into the drain as wastewater. It has been observed that about 40 liters of water is required for cooling for making 500 ml of distilled water. The water after cooling is generally left to go into the drain.
The following video has been prepared by me and is released by youtube. The video gives good information for those who want to learn about the traditional method of glass distillation and the modified Recycling Distillation Technique (Sharma, 2004) that saves gallons of water.
In a simple biological science laboratory about 2.5 liter of distilled water is used in a day which is a modest consumption. Approximately 200 liter water is required in cooling unit of distillation plant for this purpose. If this requirement is calculated for 25 working days in a month, the quantity of water wasted by one user in a month comes to about 5000 liters. In a big research laboratory or a unit of an institution or in a small industry where nearly 100 users are there, the amount of water wasted for cooling the condenser unit is estimated about 5,00,000 liters in a month .This is a big loss of potable water. In the present scenario of severe scarcity of drinking water all over the globe, we can not afford to waste such a large quantity of water during the process of distillation. Due to uncontrolled use and removal of ground water and insufficient rains in many parts of the world water is becoming day by day as an important natural resources. To overcome this problem of water loss in cooling during distillation Sharma (2004) invented a technique called recycling distillation technique in which water from the outlet tube of condenser Unit is collected, cooled and re-circulated again in the condenser unit. The technique not only saves gallons of water but also produce better results as far as condensation of vapors is concerned.
Recycling water technique (Sharma, 2004) the technique is based on a simple principle that is recycling water in condenser Unit. Sharma (2004) made some modifications in the existing distillation technique by introducing a collection, cooling and pumping devices to recycle water in the condenser tube again and again. The technique is low cost and very effective (figs). The water was cooled first by a simple indigenous cooling technique before it was allowed to enter again in condenser unit (recycling). Cooling technique involved collecting water from the outlet tube of the condenser unit in an earthen pot of about 50 litre capacity put on a cement container filled with wet sand. Once the water is filled in the earthen pot about ¾ of its capacity from the condenser unit it gets cooled. Then it is lifted to a reservoir tank of about 60 litre capacity placed at a height of 4 feet from the earthen pot, with the help of a small submersible motor placed in the earthen pot.( fig.1).The water lifting system has been made automatic by connecting an automatic water level controller with two relays in series. This has mad the recycler fully automatic means whenever water level reaches to a definite height in the earthen pot, the submersible motor switches on automatically by the water level controller. Reservoir tank can be used as plastic or earthen material depending on convenience. Cooling is more effective if reservoir tank is also an earthen pot. By this method hot water coming from condenser tube cool down in the earthen pot before it is lifted by submersible motor tank. The process of recycling water in the condenser tube goes on continuously and automatically.
This technique saves gallons of water of condenser cooling unit which otherwise go waste in the drain pipe. There is no effect in the quality of distilled water because cooling water in the condenser unit never comes in contact with water vapors. For a small distilled water apparatus (2-5 litre capacity flask) about 50 litrs water initially filled in he reservoir tank for cooling the condenser unit can be used again and again for years by recycling it. One of the advantages of this design is that existing distillation apparatus can be used for the installation of recycling unit and the total cost involved for this purpose comes to about Rs.300/- The technique is so simple that any user can install it with the existing distillation unit without any problem.. Another important application of this technique is that the distillation apparatus can be placed any where in he laboratory because this system does not require water supply from a tap of washbasin. Such water condenser water recycling device can also be attached to other plants/units such as distilleries, pharmaceutical industries etc where water is left in drain pipes after cooling the condenser unit. The user can modify this technique as per the requirement for example connecting cooling earthen pot in series or connecting more than one distillation units with one recycling unit or fast cooling water in the earthen pot using ice cubes. Many researchers have found that by controlled cooling of circulating water by adding ice cubes in the earthen pot it has become possible to do Ether based plant extraction and other similar processes. According to them this was not possible earlier because water from the plastic tanks placed in open at the roof of building used to get very hot particularly during the summers. This used to decrease efficiency during the condensation.
Advantages of Condenser water recycling Technique
(i) The first and most advantageous aspect of his technique is to prevent waste of a precious natural resource particularly in those places where natural water supply is going down every year and drinking water is not available to meet out the supply of human beings. (ii) The second advantage is that user is not dependent on tap water supply for cooling in condenser unit as in many laboratories particularly during summers tap water supply may not be available regularly and if water stops going to condenser tube through the tap it may over heat the condenser unit and can damage it. (iii) Third advantage is that, during summers, tap water coming from the regular supply from overhead tank is very hot and it fails to cause effective cooling in condenser tube. This reduces speed of distillation. Since water collected in earthen pot place on moist soil filled in cement container, gets cooled before it is lifted to he condenser unit, the speed of condensation is enhanced even in summer months. (iv) After attachment of recycling unit with condenser tube it is not needed to prepare distilled water near wash basin/sink or drain pipe. The modified distillation apparatus can be placed in any room without tap water supply or sink/wash basin or drain pipe. (v) With this technique now it is possible to do Ether based plant extraction and other similar processes by supplying pre cooled water to the condenser unit.(vi) Since efficiency of the system is enhanced, the modified technique saves lot of electrical energy.
Download the below attachments to read articles published by the author in journal / newsletter
/articles/recycling-water-during-distillation-laboratories-and-industries-saves-gallons-water-blog
