Distillation, process involving the conversion of a liquid into vapour that is subsequently condensed back to liquid form. In conventional evaporators, the energy content of the vapour stream pro duced is lost to a large extent or is only partially used. Distillation works on the principle that the vapour produced by evaporating seawater is free from salt and the condensation of the vapour yields pure water. The process vapour compression is a distillation process, where evaporation of sea or brackish water is obtained by the application of heat delivered by compressed vapour. The heat cycle involved is illustrated in the flow diagram fig. Mvc evaporator process description principles of operation. Vapor compression an overview sciencedirect topics.
Vaporcompression evaporation is the evaporation method by which a blower, compressor or jet ejector is used to compress, and thus, increase the pressure of the vapor produced. Technology and applications gea engineering for a better world. Mechanical vapor compression aquaswiss ag the thermal. Vapor compression distillation vc is a process used to produce water for injection wfi on the principle of distillation, where the water is distilled with phase change and entrainment separation. Dwsim open source process simulator discussion help. The vvc process is the more efficient distillation process available in the market today in terms of energy consumption and water recovery ratio. The vapor compression distillation vcd flight experiment, managed by nasa s marshall space flight center in huntsville, ala.
Design and experimental analysis of a vapor compression heat. According to figure 1, feed seawater enters the evaporator at a flow rate of mf and a. The condensed vapour on the top of the first cell heats and evaporates. Multiple effect distillation med is another established method of distillation, where water is heated to form vapour 10. The result is vastly improved efficiency over other distillation methods.
Ppt vapour compression cycle powerpoint presentation free. In this type of fresh water generators, the evaporation takes place at positive pressure, slightly above atmospheric pressure. The mechanical vapor compression mvc distillation is inherently the most. A free powerpoint ppt presentation displayed as a flash slide show on id. Bramcor stmc vapor compression distillation process runs as follows.
Mechanical vapor compression mvc arab journal of nuclear. Distillation optimization by vapor recompression chemical. It is exemplified at its simplest when steam from a kettle becomes deposited as drops of distilled water on a cold surface. Multiple effect distillation how med desalination works. The vapor compression evaporation process replaced the oncethrough steam generators otsg traditionally used for steam production. This allows the latent heat of the vapour to be reintroduced to the evaporator. A detailed analysis of the vapor compression distillation vcd process see. The high pr plant design described operates at maximum brine temperature of 250f and uses a pressure ratio of 1. Fedegari nonthermal range stilmas vapour compression stills. In comparison, mechan ical vapour recompression permits the continuous recycling of this energy stream by recompressing the vapour to a higher pressure and therefore, a higher energy content. Flow diagram of singleeffect vapor compression distillation system. By using this design, the encon mvc evaporator allows for minimal scaling, maximum uptime, and low operating costs. Since the pressure increase of the vapor also generates an increase in the condensation temperature. The thermodynamic efficiency is derived from the application of the heat pump principle by a large volumetric flow compressor acting as the heat pump.
Step 2 an automatic system optional regulates feedwater flow passing through. In 1939, meco patented the vapor compression process for the desalination of saltwater. When no steam is available, it is still possible to use the med process with a mechanical vapour compressor medmvc. Thermal vapour compression an overview sciencedirect topics. G venkatarathnam, s murthy 10, 2 provides various refrigerants for vapour compression and provides refrigerants from different chemical groups.
One of them is the application of a mechanical heat pump technology like vapour compression or vapour recompression for distillation. The effect of compressing water vapour is obtained by means of an ejector system 1 motivated by live steam supplied at a pressure of typically 3. In thermal vapour recompression, motive steam is used to compress part of the vapour produced in an evaporation effect from a lower evaporation pressure and temperature level to the heating pressure of the first evaporation effect. Hongfei zheng, in solar energy desalination technology, 2017. In this system, the working substance is a refrigerant like nh 3, r11, r12. Vapour compression cycle energy management handbook sixth edition, chapter 8 refrigerator air conditioning plant heat pump refrigerator electricmotordriven. How vapor compression distiller works wfi from vapor. Processes designed to save energy in evaporation plants a product to be eva porated b vapour c concentrate.
The process thermo vapour compression is a distillation process, where evaporation of seawater is obtained by the application of heat delivered by motive steam and recompressed low pressure vapour. It achieves its high efficiency in a simple manner, producing a high quality distillate. The primary disadvantage of operating at elevated temperature is that it promotes scaling. The effect of compressing water vapour is obtained by means of an electrically driven, mechanical centrifugal compressor. Some of the compressed and heated vapour is then recycled through a series of tubes passing through. Distillation of sea water by the vaporcompression method jstor. Technology and applications gea engineering for a better. So lets start with the vapour compression first, vapour compression refrigeration system. Vapor compression distillation has many advantages, namely high heattowork efficiency, small volume, no need for largescale heat sources, and the compressor being driven by electricity or diesel engine, so it is suitable for applying in ship, island, and seabase for. Vapor compression distillation pharma vapor compressions. Nasa vapor compression distillation vcd flight experiment. Aquachem uses vapor compression vc for most of its distillation systems, a process that uses its own compressed steam as its primary heat source. Since then, weve refined and improved the technology to deliver highquality potable drinking water and distilled water in some of the worlds harshest environments.
Ethanol removaldrying performance of the mavs system with binary ethanolwater. Unisim process flow diagram for vapour compression heat pump 2. In the vapourcompression system, heat is provided by the compression of vapour rather than by direct heat input from a boiler. Step 2 an automatic system optional regulates feedwater flow passing through phase 1. Mechanical vapor compression distillation of saline water is a process in which. The system combines the benefits of distillation with those of vapor compression to greatly lower the cost of distillation for removal of water or concentration of other ingredients. To understand how vapor compression distiller works it is useful to discover the essential parts of the machine. Standard models range from 100 12,000 lhr production up to 1,000lhr also available using only electrically heating. These frames from bramcor, italy, show the process steps of a vapor compression distiller, producing wfi water for injection for pharmaceutical purposes. We have been learning about fresh water generators and the procedure to operate such an fwg. Otsg generally ran on natural gas which in 2008 had become increasingly valuable. In this diagram you can see a still with steam heating.
The mechanical vapor compression mvc is among the most efficient distillation processes. Stilmas vapour compression stills produce water for injection that meets the latest requirements of the international pharmacopeias including usp, ep and jp. Multistage flash is the standard process for highvolume desalination 5 figure 11. Pdf advanced mechanical vaporcompression desalination.
Jan 04, 2012 a hybrid process integrating vapor stripping with vapor compression and vapor permeation membrane separation, termed membrane assisted vapor stripping mavs, was evaluated for recovery and dehydration of ethanol from aqueous solution as an alternative to conventional distillationmolecular sieve processes. Incoming water influent enters the system and runs through two heat exchangers which transfer heat to the influent from the outgoing pure water distillate and grey water concentrate. Process description mechanical vapor compression distillation of saline water is a process in which mechanical energy is used as the main driving force. The vapour compression refrigeration system is by far the most popular and widely used system in refrigeration and air conditioning bot for industrial and domestic applications. It is a highly energyintensive unit operation, and continuously rising energy costs make it imperative to look for ways to reduce energy requirements.
In the vc process, the vapor produced by evaporating the water is compressed to increase the saturation pressure and temperature. The encon mechanical vapor recompression mvr evaporation process involves our forced circulation flash evaporator utilizing mechanical vapor compression. Produces purified water usp purified, highly purified water hpw and water for injection wfi in accordance with all recognized pharmacopoeias meetsexceeds the exacting standards of the pharmaceutical industry and cgmp requirements. The process vapour compression is a distillation process, where evaporation of sea or brackish water is obtained by the application of. Pharmaceutical vapor compression distillation vcd, improperly known as thermocompression or such as mechanical vapor recompression mvr or mechanical vapor compression mvc distillation, too, is the main way to produce wfi water for injection and grade waters for pharmaceutical use. The water quality of evaporators is four times better which is needed for the drum boilers. Capacity range covers single effect from 100 to and double effect units from m3day to more than 2000 m3day. As the system is electrically driven, it is considered a clean process, it is highly reliable and simple to operate and maintain. It is basically a heat pump process that pumps heat from a lowtemperature reservoir to a higher temperature reservoir, just.
Multiple effect distillation with thermal vapour compression medtvc the addition of a thermocompressor to the evaporator allows the system to use the pressure of the available steam to extract low pressure vapour from an evaporator cell. Pdf distillation is one of the most widely used separation methods in the chemical industry in spite of its very high energy demand. Aquaswiss mechanical vapor compression mvc distillation is the most thermodynamically efficient process of singlepurpose thermal desalination. Other articles where vapour compression distillation is discussed. When the vapour is rapidly compressed, its temperature rises. The vapor compression distillation process is generally used in small and. The process the mechanical vapor compression mvc distillation is inherently the most thermodynamically efficient process of singlepurpose thermal desalination plants.
Step 1 feedwater enters into the first optional heat exchanger 1 tube side and is preheated, cooling at the same time the wfi to the temperature set in the hmi. Vapor compression distillation fresh water generator. Efficient ethanol recovery from yeast fermentation broth with. The majority of modern plants use the multistage flash thermal process msf or the thermal vapour compression system multieffect desalination tvc. Hello everybody, i am having some trouble trying to figure out how to correctly simulate a really simple vapor compression distillation unit. Vapour compression distillation chemical process britannica. Multiple effect distillation with mechanical vapour compression. Step 1 feedwater enters into the first optional heat exchanger 1 tube side and is preheated, cooling at the same time wfi to the temperature setup in the operator panel. Newmy a fr ene r5 united states patent 3,109,782 vapor compression distillation process wilfred samuel nathan, sunburyonthames, england, assignor to the british petroleum company limited, london, england, a british jointstock corporation filed dec.