Design of multiple effect evaporators book depository. Optimization of a multiple effect evaporator system. Two or more evaporator units can be run in sequence to produce a multiple effect evaporator shown on the right. For example, if steam is available at 220f 104c, then the last effect boiling temperature is 120f 49c. Evaporator selection considered in detail in volume 6, has been discussed by moore and hesler20 and parker21. 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. All textbooks 3,4,5 that cover evaporation present a pencilandpaper iterative approach. Definition evaporation is the process used to concentrate a solution by removing the solvent mainly water in a purified form by the application of heat. In a multiple effect evaporator the vapour from one evaporator is fed into the steam chest of the other evaporator. Direct heating is represented by solar evaporation and by submerged combustion of a fuel. Calculations on evaporators can be carried out combining mass and energy balances with the principles of heat transfer. Department of paper technology, indian institute of technology roorkee, roorkee 247 667, india.
Liquor preheating in any evaporator design, but more evident in older rising film evaporators, the entering liquor velocity and preheat requirement play a major role in determining the heat transfer coefficient at each effect. The first effect of a multiple effect evaporator is the effect to which the raw steam is fed. Two different methods are used for calculating number of effects. We design the triple effect evaporator such that the heating area in all the three effect is the same a 1 a 2 a 3 u 1.
Evaporation is the unit operation by which solvent is evaporated from the solution by boiling the liquid in suitable vessel and. Multiple effect evaporators are the equipment in which steam from an outside source is condensed in the heating element of the first effect. Mathematical model for a multiple effect evaporator system. Design of multiple effect evaporators by faizan ahmad, 9783659464003, available at book depository with free delivery worldwide. Effect of thermocompression on the design and performance of fallingfilm multieffect evaporator. 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. This book deals with the modeling and simulation of multiple effect evaporators. 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. The latent heat of the vapor leaving in single effect evaporator is not used but is discarded. In a multiple effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. The object of evaporation may be to concentrate a solution containing the desired product or to recover the solvent.
Evaporators are integral part of a number of process industries namely pulp and paper, chloralkali, sugar, pharmaceuticals, desalination, dairy and food processing, etc. Parker has attempted to test the suitability of each basic design for dealing with the problems encountered in practice, and the basic information is presented in the form shown in figure 14. Buy design of multiple effect evaporator book online at best prices in india on. An iterative procedure previously presented in the literature lambert et al. Some of the problems arising during evaporation include. Buy design of multiple effect evaporator book online at low. Sep 04, 2015 mass and enthalpy balance of a triple effect evaporator. The number of effects in a multiple effect evaporator is usually restricted to seven because after that, the equipment cost approaches the cost savings of the energyrequirement drop. Evaporator equipment there are two basic types of evaporator equipment in service today for black liquor evaporation.
A design of a multiple effect evaporator in a sugar factory is attempted. A design of a multiple effect evaporator in a sugar. Compilation of various formula from different books and published information to aid design of evapoator. The product from one cylinder passes to another cylinder and the vapor generated in first effect is used as the heat source for the next effect, and so on. Each effect would consist a heat transfer surface, a vapour separator, as well as a vacuum source and a condenser. Sep 16, 2016 the single effect evaporator uses rather more than 1 kg of steam to evaporate 1 kg of water. Design calculations for multipleeffect evaporators. Multiple effect evaporator and economy of evaporatormost important with concept. Nptel chemical engineering chemical engineering design ii. Evaporator system an overview sciencedirect topics. Online calculations for multiple effect evaporators for the sugar industry. At first sight, it may seem that the multiple effect evaporator has all the advantages, the heat is used over and over again and we appear to be getting the evaporation in the second and subsequent effects for nothing in terms of energy costs. Its divided in to three category on the basis of feed direction. 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.
Glycerol solution is to be concentrated from 7wt% to a final concentration of 80wt% the feed is available at 50993 kghr and 27c. Vapour flows and heat transfer areas are calculated. Design and simulation of a multipleeffect evaporator using. Unesco eolss sample chapters thermal desalination processes vol. Multiple effect evaporator mass and enthalpy balance. In a multiple effect evaporator, there are several vertical cylinders connected in series. A multiple effect evaporator is design to cut down the steam consumption by different operating strategies like feed, condensate and product flashing, vapor compression, vapor bleeding, feed and steam splitting and using an optimal feed flow sequence. Multiple effect stills pharmaceuticalgrade water meco. Design of multiple effect evaporators, 9783659464003. The vapours from the preceding effect are used as the heat source in the next effect. Pdf design and optimization of multieffectevaporation.
A multiple effect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water. Joye and koko, 1987 for the design of multipleeffect evaporator systems with. In indirect heating, the heat, generally provided by the condensation of steam, passes through the heating surface of the evaporator. To reduce the amount of steam needed, the evaporator is normally designed as a multiple effect evaporator.
Noniterative design of multiple effect evaporators using. Design of multiple effect evaporator, 9783845430843, a design of a multiple effect evaporator in a sugar factory is attempted. Plate heat exchanger, how it works working principle hvac industrial engineering phx heat transfer duration. Mass and enthalpy balance of a triple effect evaporator. During last seven decades, a number of models of multiple effect evaporator mee systems for its analysis have been reported. Joye and koko, 1987 for the design of multiple effect evaporator systems with backward feed is simplified and. Our vision and purpose is to target backward feed since little work is done in this domain. From the engineering view point the knowledge of technologist is enhanced. Two or more effects operate at progressively lower vacuums and thus with progressively lower boiling points. Meco multiple effect distillers are designed to produce water for injection wfi in accordance with all recognized international pharmacopoeias. Times water quantity evaporated in 1st effect evaporator. Guid to design of evaporator heat transfer chemical engineering. Pdf a simplified and generalized method to size multipleeffect. Guid to design of evaporator free download as excel spreadsheet.
Evaporator design consists of three principal elements. Design and simulation of a multipleeffect evaporator. A multipleeffect evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water. In this article discussed about history of multiple effect evaporator, rillieuxs principles for multiple effect evaporator bodies and distribution of pressure drops across the multiple effect evaporators like triple effect, quadruple effect and quintuple effect and also given online calculator for pressure drop calculation in multiple effect evaporator with values of latent heat and. Principles and pressure drop calculation in multiple effect. The amount of steam consumption in multiple effect evaporators is already mentioned in lesson 4. This method of evaporation in series is called multiple effect evaporation, and each stage is called an effect. Scribd is the worlds largest social reading and publishing site. Design of multiple effect evaporators, 9783659464003, this book deals with the modeling and simulation of multiple effect evaporators. A high heat transfer rate is obtained by incorporating both the falling film and rising film evaporators in a single unit. Brief discussion on accessories like condenser is done. Sep 29, 20 this book deals with the modeling and simulation of multiple effect evaporators.
The main problem was how to design an adequate system for the even distribution of liquid to each. The me stills are modular in design and include options for simultaneous and exclusive pure steam production. Modeling and simulation faizan ahmad, naseem ahmad khan on. Sep 04, 2015 overview of a multiple effect evaporators. The design of an evaporation unit requires the practical application of data on heat. Rising film evaporators also referred to as a long tube vertical ltv evaporator, this design has dominated the industry for decades and remains a common sight in older kraft mill operations. 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. Evaporation is the removal of solvent as vapor from a. Design and simulation of a multiple effect evaporator system. Multiple effect evaporator and economy of evaporator most important with concept. In our sugar industry the solvent is juice, heat is supplied.