In each stage the feed water is heated by steam in tubes, usually by spraying saline water onto them. It is thus a thermal separation, or thermal concentration, process. Multiple effect evaporator is the combination of several sets single effect evaporator. Mechanical vapor recompression evaporators swenson technology. In a double effect evaporator, the vapor product off the first effect is used to provide energy for a second vaporization unit. The object of evaporation may be to concentrate a solution containing the desired product or to recover the solvent. With addition of each effect steam economy of the system also increases. Effects can be staged when concentrations of the liquids in the effects permits. We define the evaporation process as one that starts with a liquid. Sep 16, 2016 the single effect evaporator uses rather more than 1 kg of steam to evaporate 1 kg of water. Detailed design of a single effect evaporator with thermal vapor re compression. Raj evaporators is one of top quality multi effect evaporator and various evaporator product manufacturers and exporters in india jai ganesh vision, b wing, 3rd floor, jai ganesh fame building, akurdi, pune 411 035 india. Steam condensation inside horizontal tubes and seawater evaporation on the outer side is the heart of one of the most common med processes. Design, modelling and simulation of multiple effect.
In our case we have taken 3 stage multiple effect evaporation system. The multiple effect configuration combines two or more evaporator bodies to conserve steam, which is condensed in the first effect heat exchanger only. Multipleeffect evaporators mees are common to industries that concentrate different products, regenerate solvents,or separate solidliquid mixtures. Principle of multiple effect evaporator multiple effect evaporator is a thermal evaporation process, widely used for concentration of various liquids in the form of solution, suspension, and emulsions concentration is accomplished. Multiple effect evaporators maximize steam economy as vapor generated from one effect is used to drive another. In a multipleeffect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Evaporator operation in evaporation, solids may come out of solution and form a deposit or scale on the heat transfer surfaces.
A multipleeffect evaporator is an apparatus for efficiently using the heat from steam to evaporate water. Evaporators are integral part of a number of process industries namely pulp and paper, chloralkali, sugar, pharmaceuticals, desalination, dairy and food processing, etc. These factors make effective evaporator control crucial to. Abstract the effect of salinity is to reduce evaporation but at the same time to increase the energy returned to the atmosphere by other physical processes, so that under equilibrium conditions a saline. However, every text that covers multiple effect evaporation presents t he solution. Pdf design of heat integrated multiple effect evaporator system. Our vision and purpose is to target backward feed since little work is done in this domain. When carrying out the thermodynamic design for a multipleeffect forcedcirculation evaporator system the procedure is basically as follows. Critical operational and product characteristics critical operational and product characteristics of the solu.
Multipleeffect distillation or multi effect distillation med is a distillation process often used for sea water desalination. This is to certify that the project entitled design and simulation of a multiple effect evaporator using vapor bleeding is an original work done by monalishanayak, roll no. The purpose of this article is to investigate the influence of using feed water preheaters in multiple effect distillation systems with thermal vapor compression medtvc. Evaporation technology gea engineering for a better world. This heat can be recovered and reused by employing multiple effect evaporators.
Dec 24, 2017 what does multiple effect evaporator mean. In case of multiple effect evaporation plants, the exhaust vapors from the product are used to heat the downstreamarranged evaporation effect so. This concentrated liquids in a gentle and efficient manner in a way unparalleled in its time. Pdf a simplified and generalized method to size multipleeffect.
The single effect evaporator consists of a container or surface and a heating unit. Design and simulation of a multipleeffect evaporator using. Density of liquid 10 wt% glycerol 1019 kgm3 density of water vapour pmrt. These metrics are regularly updated to reflect usage leading up to the last few days. Multipleeffect vacuum evaporators condorchem envitech. The multipleeffect evaporator was invented by the africanamerican engineer norbert. Single effect evaporation is simple but fails to utilize the steam effectively, while multiple effect evaporators evaporate more quantity of water per. This method of evaporation in series is called multiple effect evaporation, and each stage is called an effect. Usually there is double effect evaporator, three effect evaporator or. Water evaporated in the first effect vapor body is condensed in the second effect heat exchanger, which provides energy for evaporation in the second effect vapor body and so on for additional. The figures below show how the multiple effect design concept functions.
Evaporator is one of the most energy intensive sections of a number of process industries such as pulp and paper, sugar, desalination, pharmaceuticals, dairy. Design of multiple effect evaporator, 9783845430843. Studies of evaporation the effect of salinity on evaporation by g. A multiple effect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water. In any evaporation operation, the major process cost is the steam consumed. Desai page 1 study the steam economy of multiple effect evaporator plant producing sodium sulphate and its simulation a project report submitted by rohan a. Because the boiling point of water decreases as pressure.
Using a multiple effect evaporator, the operation is based on the steam produced in one effect being used as the heat source for the following effect. As a result, many types of evaporators and many variations in processing techniques have been. Design of multiple effect evaporators, 9783659464003. Investigation of multiple effect evaporator design. Evaporation is the removal of solvent as vapor from a. Calculations on evaporators can be carried out combining mass and energy balances with the principles of heat transfer. In a multiple effect evaporator the vapour from one evaporator is fed into the steam chest of the other evaporator. Evaporators are the largest heat users and major contributors to losses in sugar cane factories. The energy savings possible through the use of a recompression evaporator are significant. Design and simulation of a multipleeffect evaporator using vapor bleeding.
Much of this latent heat, however, can be recovered and reused by employing a multiple effect evaporator, that is, vapor from one effect serves as the. It was easy to control and had a compact arrangement. Design and simulation of a multipleeffect evaporator using vapor. An iterative procedure previously presented in the literature lambert et al. The segregation of the duty is combined with a pressure gradient across the entire evaporator to allow for reuse of energy in the system. Feeding of multiple effect evaporator multiple effect evaporator divided in to four categories on the basis of feed direction as shown figure 25. Considering the heat balance of a single effect evaporator the heat content enthalpy of the evaporated vapor is approximately equal to the. Brine zero liquid discharge zld fundamentals and design. Pdf design of heat integrated multiple effect evaporator. A thesis on design of heat integrated multiple effect evaporator system submitted by ghoshna jyoti 210ch1201 for the partial fulfillment of master of technology under esteemed guidance of dr. Design of multiple effect evaporators has received considerable attention over the last 30 years and several key contributions have appeared in the literature. Vapour flows and heat transfer areas are calculated. Evaporator, industrial apparatus for converting liquid into vapour. Design and simulation of a multiple effect evaporator system.
Multiple effect evaporator design selection of type of evaporator using some parameters is presented for the best design of multiple effect evaporator in table 1. While the design criteria for evaporators are the same regardless of the industry involved, two questions always exist. Evaporator is one of the most energy intensive sections of a number of process industries such as pulp and paper, sugar, desalination, pharmaceuticals, dairy and food processing, etc. The use of multiple effect evaporation allows for the capture and use of waste heat vapours off the falling film evaporator process, to replace primary steam usage throughout the refinery and in particularly, in the evaporation. Also, it is required to make to evaluate the amount of steam saved by the use of vapour compression. Noniterative design of multiple effect evaporators using excel addins. Water evaporated in the first effect vapor body is condensed in the second effect heat exchanger, which provides energy for evaporation in the second effect vapor body. Singleeffect evaporators are often used when the required capacity of operation is relatively small andor the cost of steam is relatively cheap compared to the evaporator cost. Thermal integration of multiple effect evaporator in sugar. This type of multiple effect system is perfect for continuous feed applications, as fluids are progressively reduced in each effect to final concentration discharge. The amount of steam consumption in multiple effect evaporators is already mentioned in lesson 4.
Mathematical model for a multiple effect evaporator system. However, for largecapacity operation, using more than one effect will markedly reduce steam. Water evaporated in the firsteffect vapor body is condensed in the secondeffect heat exchanger, which provides energy for evaporation in the secondeffect vapor body and so on for additional effects. The increase in latent heat with decreasing pressure and additional radiation losses affect, the economy as the number of evaporators used is increased. A multiple effect evaporator is an equipment system for efficiently using the heat from steam to evaporate water. Schematic view of industrial multi effect evaporation mccabe et al.
For example, if steam is available at 220f 104c, then the last effect boiling temperature is 120f 49c. Design calculations for multipleeffect evaporators. A multipleeffect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water. The characteristic is to heat the next effect evaporator by used steam produced from the front effect, so as to reduce energy consumption. This system is used in a single effect evaporator or in the first stage of a multiple effect evaporator. Design of multiple effect evaporators, 9783659464003, this book deals with the modeling and simulation of multiple effect evaporators. This method of evaporation in series is called multipleeffect evaporation, and each stage is called an effect. Evaporation is an operation used to remove a liquid from a solution, suspension, or emulsion by boiling off some of the liquid. The use of this system requires that steam be available at high pressure, and low. A multi effect vacuum evaporator consists of a set of interconnected evaporators where the first effect is the first evaporator, and so on. Design, modeling and simulation of multiple effect evaporators. Dryer design heat and mass energy balance duration.
National institute of technology, rourkela department of chemical engineering, national institute of technology, rourkela. Modeling and simulation faizan ahmad, naseem ahmad khan on. In a single effect evaporator, steam provides energy for vaporization and the vapor product is condensed and removed from the system. Its divided in to three category on the basis of feed direction.
This type of evaporators have been specially designed to provide high degree of agitation, effecting heat transfer as well as scrapping the walls of the evaporator to prevent deposition. Multiple effect evaporator the multipleeffect configuration combines two or more evaporator bodies to conserve steam, which is condensed in the firsteffect heat exchanger only. Dynamic simulation of multiple effect evaporators in paper industry using matlab deepak kumar, anjana rani gupta, somesh kumar udepartment of mathematics, niet greater noida, up. This causes a gradual increase in the resistance to heat transfer and, if the same temperature difference is maintained, the rate of evaporation decreases with time. Online calculations for multiple effect evaporators for the sugar industry. With hundreds of plants already realized all over the world reda s. The purpose of this article is to investigate the influence of using feed water preheaters.
The entire evaporator duty amount of water or solvent being removed can be segregated into multiple evaporator effects. Scribd is the worlds largest social reading and publishing site. Noniterative design of multiple effect evaporators using. A multiple effect evaporator is an evaporator system in which the vapor from one effect is used as the heating medium for a subsequent effect boiling at a lower pressure.
Optimum design and operating conditions of multiple effect evaporators. Multiple effect evaporator is used for steam economy. Evaporation technology multipleeffect evaporation plants. The effluent streams are sent to the resin plants and after removal of impurities it is fed to the multiple effect evaporator. Evaporator design consists of three principal elements. The design calculations required for a multipleeffect evaporator are complex enough to provide a real challenge for implementation using a spreadsheet. Investigation of multiple effect evaporator design semantic scholar. Multipleeffect evaporators maximize steam economy as vapor generated from one effect is used to drive another. In a multiple effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Pdf optimum design and operating conditions of multiple effect. Falling film evaporators can be operated with small temperature differences between the heating media and the boiling liquid and they also have short product contact time. Schematic view of a horizontal tube multi effect distillation plant ide design, internet publication. These are forward feed multi effect evaporator, backward feed multi effect evaporator, mixed feed multi effect evaporator and parallel feed multiple effect evaporator.
Citations are the number of other articles citing this article, calculated by crossref and updated daily. Evaporators falling film evaporators manufacturer from. Multiple effect evaporator control is a problem that has been widely reported in the pulp and sugar industries. Multipleeffect evaporator design the design calculations required. Hermes center for applied thermodynamics, department of mechanical engineering, federal university of parana p. The purpose of this tabulation is to provide a quick. Given that evaporation is a separation system, the presence of three different fluids is found.
Unlike singlestage evaporators, these evaporators can be made of up to seven evaporator stages or effects. Single effect evaporation is simple but fails to utilize the steam effectively, while multiple effect evaporators. Optimization of a multiple effect evaporator system. Further technical developments led to the first wiegand falling film evaporator, built in 1952, which combined these consider. Mist flow conditions should be avoided because poor heat.
Multiple effect evaporator the multiple effect configuration combines two or more evaporator bodies to conserve steam, which is condensed in the first effect heat exchanger only. The most of criteria in this table are selected and classifications are made by using the letters in various grades. Because the boiling temperature of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel at the highest pressure requires an external source of heat. The use of vapour compression allows us to use the energy in the vapour leaving the last effect. The amount of steam consumption in multiple effect. A calculational procedure useful in the design of multipleeffect evaporator systems is presented in this work. The falling film evaporators can be single effect or multiple effects depending on the capacity. Article views are the countercompliant sum of full text article downloads since november 2008 both pdf and html across all institutions and individuals.
That is possible because the equipment used for juice concentration, that is, the multiple effect evaporator mee, is divided into several stages, using the heating steam from backpressure turbines st, only in the first effect, thus allowing other effects to take advantage of the thermal energy of vv generated in the operation itself. The process is generally done in multiple evaporation sys of the total cost. Scrapped surfacethin film evaporators are designed for evaporation of highly viscous and sticky products, which cannot be otherwise evaporated. The process inside and andritz evaporator relies on a free flow falling film of liquor over the surface of the lamella. In the evaporator, the seawater fed in is heated to its boiling temperature and is partly. The latent heat of the vapor leaving in single effect evaporator is not used but is discarded. In case of multipleeffect evaporation plants, the exhaust vapors from the product are used to heat the downstreamarranged evaporation effect so that the steam consumption will be reduced accordingly. Optimization of parameters of multi effect evaporator used. Each effect, in itself, act as a single effect evaporator, and each has a temperature drop across its heating surface corresponding to the pressure drop in that effect. This book deals with the modeling and simulation of multiple effect evaporators. Mees are common to industries that concentrate different products, regenerate solvents, or separate solidliquid. Shabina khanam may2012 department of chemical engineering national institute of technology rourkela, orissa. In case of multiple effect evaporation plants, the exhaust vapors from the product are used to heat the downstreamarranged evaporation effect so that the steam consumption will be reduced accordingly. By means of the rate equations, calculate the heating surface.
Sep 04, 2015 overview of a multiple effect evaporators. Multiple effect evaporator mass and enthalpy balance youtube. Therefore, methods of reducing steam consumption or of increasing economy, defined as mass of vapour produced per unit mass of steam consumed are very important. Pdf features of multieffect evaporation desalination plants.
Single effect evaporator can be wasteful of energy if the vapors heat is not used. Pdf detailed design of a single effect evaporator with. Design of triple effect evaporator developed by a program. Evaporators are classified by the number of effects. A simplified diagram of a forwardfeed triple effect evaporation system is. Geawiegand has substantially contributed to the development of evaporation technology. Design criteria for multiple effect evaporators in alumina. Dynamic simulation of multiple effect evaporators in paper.
In some cases multipleeffect evaporators have been converted to mvr to take advantage of changes in the relative cost of electric power and steam. Features of multi effect evaporation desalination plants. Design and simulation of a multipleeffect evaporator. There could be single effect evaporator or multiple effect evaporators. During last seven decades, a number of models of multiple effect evaporator mee systems for its analysis have been reported. The first wiegand evaporator, built in 1908, was a patented multipleeffect circulation evaporator.
If the heating surfaces so determined are not essentially equal. Design criteria for multiple effect evaporators in alumina refinery hi friends, in earlier post, we have already discussed that the net evaporation requirement in efficient alumina refinery ranges from 2. The significant advantage of this arrangement is that it allows the original heat input to the system to be reused in each effect. To produce the equivalent steam from one pound of 234 f evaporator condensate requires 999 btu. The objective of this paper is to develop a mathematical model and an algorithm to design a multiple effect evaporator system. Design of multiple effect forcedcirculation evaporators. The stripper is part of the multiple effect evaporator system.
1277 1315 1254 219 843 1523 683 927 1150 210 634 983 869 891 238 325 707 523 701 1530 284 635 1425 434 661 715 1063 398 735 297 32 1254 581 629 1331 69 1351 66 437 827 116 627 400 1408