I'll use a search engine for you. More frequently known as vapor-compression distillation. From : http://www.goodh2o.com/wht-s-ds.htm
'Commercial Distillers Many commercial operations use multiple-effect distillers, to provide from 75 to millions of gallons per day. These units typically contain a number of boiling chambers, with the first chamber being under increased pressure, and successive chambers having progressively decreasing pressure. This takes advantage of the fact that the greater the steam pressure, the higher the boiling point and temperature of the steam produced. The steam created in the first high-pressure chamber is "superheated" to a point well above the temperature needed to create steam in the lower-pressure chambers. As this superheated steam moves through tubes surrounding each of the succeeding boiling chambers, it "flash" vaporizes some of the cooler, lower-pressure water in each chamber. The flash vapor is then condensed into distilled water, as is the superheated steam when all of its heat energy is exchanged. The self-sustaining nature of this process can be quite efficient for large quantities of water, since only an electric or gas heating element is required for the first boiling chamber as an energy source. A variation of the multiple-effect distiller concept is the vapor-compression distiller, which is typically used in commercial applications requiring between 25 and 5000 gallons per day. Vapor-compression water distillers also use high-pressure, superheated steam to boil water; however, they only use a single chamber. The water in the boiling chamber is initially converted to steam at normal pressures and temperatures by an electric or gas heating element. The steam then passes through an electric compressor; the compression causes it to become superheated. The superheated steam is then directed through tubes back into the boiling chamber, where it eventually takes over the boiling process, condensing into distilled water as the heat transfer occurs. These systems are typically more efficient than multi-stage units, since the energy required to operate the compressor is less than that required to heat water using a heating element. The greater efficiency usually brings with it a greater cost, as compared to multistage units. Both multi-stage and vapor-compression distillers can incorporate various forms of filtration to make a broadly effective treatment system. These systems can provide water for such uses as commercial water bottling. Both systems also require water that is softened to be practical, to prevent debilitating scaling with resultant heat transfer losses and maintenance costs. At the municipal level, both multi-stage and vapor-compression distillation can provide large quantities of distilled water for drinking use, and are especially used in distilling seawater for use in arid areas adjacent to the oceans.' Ivan. -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: [email protected] -or- [email protected] with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: [email protected] List maintainer: Mike Devour <[email protected]>
