GEA Messo AG

EvaporationCrystallization

and Chloralkali

Process Technologies byGEA Messo Switzerland

www.geamesso.com

The Process EngineeringDivision (P-Division) of GEAis a world leader in liquid andsolid processing technologies.In total, the P-Divisionemploys 3,300 people whoproduce sales of approx. 900 million Euro and providesa complete range of servicesand process systems to thebeverage, chemical, dairy,food and pharmaceuticalindustries.

GEA Messo AG is an established and international renownedfirm of chemical engineering provider and process plant con-tractor and concentrates its business activities on a selectedrange of special process technologies based on a combinationof extensive experience accumulated over many years in projectexecution, process development and cooperation with spe-cialized companies.

Since August, 2004 GEA Messo AG, has been incorporated inthe GEA group, one of Europe largest technologies group.ESCHER WYSS evaporation and crystallization plants are nowdesigned and supplied by GEA Messo AG.

In 1999 the well known Chloralkali Technology of KREBS SWISSLtd. has been taken over and the wide range of different tech-nologies incl. complete plants for the Chloralkali industry arenow designed and supplied by GEA Messo AG.

With annual sales of around 4.1 billion Euros and 17,000employees, GEA Group is an international technology basedgroup with its core competencies in the areas of customizedsystems, process equipment, process engineering and plantengineering.

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Company Profile

GEA Group Aktiengesellschaft

CustomizedSystems

Air TreatmentRefrigeration

Process Equipment

Dairy farm Systems Process Equipment Mechanical Seperation

Process Engineering

Energy Technology Process Engineering

Plant Engineering

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GEA Process Engineering FranceGEA MessoGmbHGEA WiegandGmbHGEA Messo AGNiro Inc.

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Evaporation

Crystallization

Salt Works

Chloralkali

Effluent Treatment

Historical Background of Evaporation Technology

ESCHER WYSS SystemEvaporation plants using the ESCHER WYSS system have beenbuilt for more than 80 years. The first contract to supply a multi-stage compressor for mechanical vapour recompression in a saltplant dates back to the mid-twenties. ESCHER WYSS manufac-tured the compressors in their own workshops and were alsoasked to fabricate the evaporator for this plant which recoveredsalt from brine on a continuous basis. This project initiatedESCHER WYSS’s activities in the field of evaporation technologyand manufacture of the corresponding equipment.

The first salt plant was followed by contracts for further saltplants as well as evaporation plants for other liquors, knownfrequently as concentrators. The scope of supply was limited tothe main vessels, which were assembled in our own workshopsexclusively until the mid-fifties. By installing a circulation pump inthe centre of the calandria type evaporator the forced circulationsystem was created. This evaporator became famous for itsexcellent heat transfer rates and salt slurry handling character-istics. The drive was mounted at the top of the vapour dome andconnected by a shaft to the propeller in the base.

Experience grew from the widening range of applications in thisspecial thermal separation technique. Through research anddevelopment new technologies were established and ESCHERWYSS was transformed from being a manufacturer of vesselsinto a contractor and supplier of technology and complete plants.

The implementation of this process technology and the associatedequipment was characterised by its fast progress in developingnew markets, for example, in the basic chemical industry, in thetreatment of wastewater from flue gas scrubbers, to name onlya few. In all these plants the design was based upon achievingoptimum energy utilization whilst fulfilling the environmentalrequirements.

Evaporation plants based upon ESCHER WYSS technologywere designed and supplied under the company names:1924 - 1981 ESCHER WYSS AG1981 - 1991 Sulzer-Escher Wyss AG1992 - 1996 Sulzer Chemtech AG1996 - 1999 CT Environment AG1999 - 2000 VA TECH WABAG2001 - 2004 Messo AGsince 2004 GEA Messo AG

Technologies, Engineering and ServicesGEA Messo AG supplies technology, engineering and services for:� Evaporation� Crystallization� Salt Works� Chloralkali� Effluent Treatment According to the client’s requirements, we can then act as generalcontractor or as a partner to other firms. In connection withthe supply of equipment the following services are available.

Project Services� Process studies� Pilot tests� Model engineering� Feasibility analyses� Basic engineering� Quality control project management� Erection supervision� Personnel training� Commissioning

After Sales Services� Technical services� Maintenance assistance� Plant management assistance

Various� Studies and expertises/surveys� Pre-Engineering� R & D projects/process development� HAZOP studies� Waste heat utilization/total energy concepts� Revamping of plants

References More than 400 plants have been implemented in all continents,many being repeat orders from satisfied clients.

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The extensive know-how thathas been gained in realizingevaporation plants gives GEAMesso AG the depth of expe-rience needed to design newplants which are tailored tothe client’s exact requirementsand which minimise invest-ment and operating costs.

Characteristics of theEvaporation ProcessesIn the technology of evapora-tion GEA Messo AG is theleading designer of plantswith multiple-effect andevaporation with thermo-compression process andcombination thereof as wellas the multiple-stage flashevaporation process.

We know how to engineerhighly efficient processes andlay out highly efficient plants,you get lower initial invest-ment cost and lower operatingcosts.

Multiple-effect EvaporationClassical multiple effect evaporation uses low-pressure steamfor heating of the first effect and utilizing the vapour for heatingin the subsequent stage. The factor of the number of stagesdepends on the ratio of operating costs to capital investmentwhich subsequently depends upon the evaporation capacityand boiling point elevation of the solution.

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Evaporation

Evaporation withThermal Compression (Vapor Recompression)We apply the thermal- or themechanical vapor recompres-sion. The increased fuel costsfor production of steam favoursthe adoption of vapour com-pressors for evaporation plantsof all kinds.

Simplified flow sheet of a six effect falling film evaporation process

Simplified flow sheet of a MVR evaporation process

Multiple Stage Flash EvaporationFor application involving large throughputs of process solutionwith a relatively small rise in concentration or low evaporationratio, the combination of multiple stage pre-heater systems forheat recovery followed by multiple stage flash evaporation isadvantageous. Multiple stage flash evaporators are also eco-nomic for solutions with low boiling point elevation both froman investment and operating point of view.

Evaporator TypesTo satisfy the wide spectrum of process requirements which anevaporation system has to meet, GEA Messo AG supply allevaporator types which are of proven design. Constructionmaterials, such as: carbon steel, rubber lined, monel clad, fullmonel, nickel, titanium, nickel alloys, stainless steel, plasticmaterials etc. are utilized.

GEA Messo AG design plants for the concentration of liquorsmainly, evaporators with thermal recirculation and non-recurrentflow or recurrent circulation. For special cases a forced circulationsystem with a high heat transfer coefficient has been developed.The most suitable type has to be chosen in each case with dueconsideration of the main factors, namely: sensitivity of theliquor to temperature, tendency to scale, accessibility for main-tenance, limited use of expensive construction materials.

References:

� National Aluminium Company Ltd, (NALCO), India, Aluminate liquor concentration, 2 lines of 135-185 tons per hour evaporation

� Quimigal UNITECA, Portugal, Caustic soda concentration, 300 tons per day NaOH from 32% to 50%

Flash evaporator withseparate heating cir-cuit

Rising film evapora-tor with integratedheating chamber

Falling film evapora-tor

Forced circulationevaporator withintegrated heatingchamber

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Simplified flow sheet of a multiple stage flash evaporation process

The extensive know-how thathas been gained in realizingcrystallization plants givesGEA Messo AG the depth ofexperience needed to designnew plants which are tailoredto the client’s exact require-ments and which minimiseinvestment and operatingcosts.

Super saturation is the keyparameter for the crystalliza-tion and means the tempo-rary increase of concentrationof the solute in the solventabove its equilibrium, and isproduced by evaporation,cooling, chemical reaction,salting out, etc.

The experienced engineers ofGEA Messo AG will plan,design and construct yourcrystallization plant for thechemical-, pharmaceutical-and food products. We knowhow to optimise the crystal-lization to achieve larger orsmaller crystalls with the cor-rect moisture content of yourrequirement under applyingthe full range of crystalliza-tion technologies.

Crystallization ProcessesGEA Messo AG has extensiveexperience in building plantswith

� Evaporative crystallization� Vacuum cooling

crystallization� Recrystallization and

reprecipitation

Evaporative CrystallizationEvaporative crystallization is usually a process that is conductedunder vacuum. This process is chosen when solubility of thesolute is nearly independent of temperature. Special scalingproblems are not a serious problem as long as boiling on theheater surface is avoided.

Vacuum Cooling CrystallizationVacuum cooling crystallization is usually chosen if the solubilityof the substance to be crystallized is strongly dependent ontemperature. Vacuum cooling crystallization is the preferredcooling crystallization method for continuous operation condi-tions, due to the fact that the super saturation is generated byadiabatic cooling of the solvent at the liquor level.

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Crystallization

Simplified flow sheet of a MVR evaporation/crystallization process

Simplified flow sheet of a multiple stage vacuum cooling crystallization process

RecrystallizationRecrystallization is applied when the feedstock is a salt/solidsinstead of a solvent. In the process the feed salt is dissolved inunsaturated circulation brine. Impurities are removed bydecantation. The purified salt is crystallized in a vacuum coolingcrystallization.

ReprecipitationReprecipitation of salt is carried out by dissolving of a salt inthe mother liquor and simultaneously precipitation of the productsalt. This process is applied in cases of different solubilitybehaviour of the two salts.

References:

� Bitterfeld, Germany, salt/sulfate crystallization,10.9 tons per hour salt plus 0.29 tons per hour sulfate

� SOM Nitratos, Chile,potassium nitrate crystallization, 12.5 tons per hour

Typical examples ofsuch processes are:Crystallization by evaporationfor the production of variousinorganic and organic com-pounds such as but not limitedto sodium chloride (salt frombrines), potassium chloride,ammonium sulphate, sodiumsulphate and adipic acid.

Crystallizers are of continu-ously operated forced circu-lation type. They may bedesigned with internal orexternal circulation, with orwithout baffle zones and withno, partial or total classifica-tion.

Crystallizer typesThe control of super satura-tion, crystal suspension den-sity and crystal breakagerequires forced circulationevaporation systems. GEAMesso AG design the crystal-lizier for all sizes, materials ofconstruction, with integralheating chambers, with exter-nal heating circuits or withcombiened circulation systemsfor special quality of crystalls.

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Simplified flow sheet of a recrystallization process

GEA Messo AG can supply the complete plant to process what-ever type of salt resource you have – solar salt, rock salt, sea salt, orbrine from solution mining – into whatever type of salt you need:moist or dry, fine or course, cubic, spherical or dendrite, white,free-flowing, with additives (e.g. potassium iodide), packed inbags, bottles, or boxes, salt for the table, factory, farm, or icyroad. Depending on the raw material and plant design, we canachieve purity up to 99.99% NaCl.

The utilization of natural salt resources depends upon the geo-logical characteristics, the requirements of the end-users andeconomical aspects. These considerations are decisive in theselection of the most suitable technology to satisfy the qualityrequirements for vacuum salt.

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Salt Works

GEA Messo AG has supplied more than 100plants and is world leader for mechanicalvapour recompression technology and com-bined sodium chloride/sodium sulphate plants.The extensive know how that has been gainedin realizing these plants gives GEA Messo AGthe depth of experience needed to design newsalt plants which are tailored to the clientsexact requirements and which minimise invest-ment and operating costs.

GEA Messo AG is re-known worldwide forthe design and supply of vacuum salt plantswhich match the individual requirements oftable salt as well as for producing high gradevacuum salt, suitable for Chloralkali electroly-sis plants.

Simplified flow sheet of combined NaCI/Na2SO4 process

We choose the most efficient and economicaltechnologies for each plant:

� Chemical brine purification� Multiple-effect evaporation crystallization� Mechanical vapour recompression� Thermal vapour recompression� Recrystallization

and we build all types of plants:

� Common salt production plants� Brine purification plants� Vacuum salt plants using purified brine for super

high-grade salt � Complete vacuum salt plants with brine purification,

storage, bagging, logistics� Recrystallizer plants for the production of vacuum salt� Combined plants for high purity requirement

The most common crystallizer type used for salt is the ForcedCirculation Crystallizer (FC-type). GEA Messo AG has extensiveknow how and experience in designing the components in specialmaterial of construction like monel, titanium, special alloys andstainless steel.

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References:

� Pimai Salt Company, Thailand, 5 table salt plants, production rate: 15, 30, 45, 60, 60 tons per hour salt

� Jintan Saltworks, China, table salt plant, production rate 87 tons per hour

GEA Messo AG offers thecomplete range of processtechnologies for the produc-tion of Chlorine, CausticSoda, Sodium Hypochlorite,Hydrochloric Acid and Iron(III) chloride. The basis is acombination of extensiveexperience, close cooperationwith leading membrane cellelectrolysers suppliers, processdevelopment in own labora-tory and cooperation withspecialized companies andwith scientific institutions.

GEA Messo AG provides all services required for the executionof complete Chloralkali plants or of specific designed processunits. We are available to our clients as required by the specificproject.

The experienced engineers of GEA Messo AG will plan, designand build your Chloralkali plant or process unit for the pro-duction and treatment of chlorine, caustic soda/potassiumhydroxide and hydrogen by electrolysis of NaCl or KCl brineand related plants including:

� Chloralkali electrolysis plants in collaboration with leading electrolyser providers,

� Chlorine processing and handling plants� Nitrogentrichloride removal and decomposition units� Brine preparation and purification plants� Hydrogen processing plants� Chlorine absorption and sodium hypochlorite production

plants� Processing and concentration plants for caustic soda or

potassium hydroxide� Iron (III) chloride production plant

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Chloralkali

Brine preparation andpurificationMost of Chloralkali electrolysisplants build by GEA MessoAG are operated with brineprepared from local salt, thecompany’s experts are conse-quently familiar with the par-ticularities of the salts availablein many different countries.They can thus optimize theconcept for any particularbrine preparation and purifi-cation plant. The team’s vastexperience will give optimumresults independent of whetherthe feed stock is vacuum salt,solar sea salt or rock salt. Ourspecialists will evaluate themost economical alternativesfor some or all of the follow-ing process steps:

� Primary brine dechlorination

� Secondary dechlorination� Saturation� Chemical treatment� Clarification� Filtration� Ion exchange purification

Iron (III) chloride productionIron (III) chloride is a verypopular agent for the treat-ment of both drinking waterand waste water, where it isused as a flocculants. Theprocess using chlorine gasand scrap iron has been con-tinuously perfectioned andthe emission from the plantsare negligible whereas theproduct quality is outstanding.

Chlorine processingand handlingGEA Messo AG design andsupply chlorine processingand handling facilities tomatch exactly the client’srequirement and can includessome or all of the followingprocess steps:

� Cooling and filtration� Drying to achive lowest

possible moisture contents� Scrubbing to remove

Nitrogentrichloride and/or Bromine

� Safe decomposition of Nitrogentrichloride

� Compression with liquid ring-, reciprocating piston-or centrifugal compressor

� Liquefaction to achieve either highest efficiency or highest liquid chlorinequality.

� Storage and transfer of liquid chlorine

� Filling into containers/ tonners and bottles

� Evaporation.� Normal vent gas and

emergency absorption into caustic soda.

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References

� Borregaard, Norway, Chloralkali plant for 140 tpd NaOH with bipolar membrane electrolysers of AGC, conversion project.

� THASCO, Thailand, Chlorine drying units forup to 200 tpd chlorine gascontaining < 15 ppm moisture.

Chloralkali electrolysisGEA Messo AG is cooperatingclosely with leading mem-brane cell technology pro-viders and will safeguard theimplentation of the electrolysertechnology in the Chloralkaliplant. The related processsection for feeding of ultrapure brine to the electrolysersand for the processing of theproducts generated in theelectrolysers will be designedand supplied by GEA MessoAG for the specific require-ments of the electrolysis tech-nology.

GEA Messo AG specializes in treatment systems for processstreams and wastewater containing inorganic and organicchemicals. We apply our evaporation and crystallization tech-nology to efficiently treat:

� Effluents from flue gas scrubber� Process liquor from TiO2 plants� Waste acid from scrubber� Waste liquor from pulp- and paper plants� Waste water from incineration plants� Process waste streams from industrial plants

In various industries ranging from titanium dioxide, magnesiumoxide, pulp and paper to chemical processing, GEA Messo AGimplemented complete effluent treatment solutions. The systems are built to recover

� Ammonium sulfate� Sodium sulphate� Sodium chloride� Sulfuric acid� Calcium chloride� Inorganic mixed salts� Hydrochloric acid

GEA Messo AG appliesthe following evapora-tion and crystallizationtechnologies:

� Multiple effects� Thermal and mechanical

vapour recompression� Evaporative crystallization� Vacuum cooling

crystallization

The most common evaporatorand crystallizer types usedare: flash, rising film, fallingfilm and forced circulationevaporator as well as theforced circulation type crys-tallizer. GEA Messo AG hasextensive know how andexperience in designing thecomponents in special materialof construction like carbonsteel, rubber lined, specialalloys, graphite, plastic mate-rials such as FRP, FEP and sil-icon cast iron etc.

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Effluent Treatment

Examples:

Treatment of WasteSulfuric AcidThe treatment of waste acidfrom the production of TiO2

is illustrated as follows.The production of white pig-ment by the older of theprocesses in use today is basedupon the leaching of ilmeniteore with H2SO4. For every tonof TiO2 product, about 8 tonsof waste or weak acid withapproximately 20% sulfuricacid is produced. This streamwhich is contaminated withmany soluble impurities istreated in a two stage process.The treated acid can be reuti-lized for ore leaching. Throughsystematic recycling, pollutionof the oceans can be avoided.

Waste Water From FlueGas CleaningDesign and supply of plantfor recovery of salt, calciumchloride and gypsum from fluegas scrubber. The plant is spe-cially designed to crystallizeand separate the salts.

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References:

� Borsodchem, Hungary, Treatment of waste water to recover sodium chloride,capacity 4.25 tons per hour NaCl

� Nordenham, Germany, Treatment of waste sulfuric acid

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Quality Assurance

The core of the ISO 9000Quality Standard is a seriesof five international standardsthat guide the developmentand implementation of oureffective quality managementsystem. Placement company’s ISO9001 : 2000 certificationdemonstrates our commit-ment to ensuring a consistent,world-class level of qualitythroughout all our businessprocesses and managementin our quest to develop,

design, fabricate, implementedprocesses, equipment andplants at exceptional customerservice.The management system ofGEA Messo AG is implemented since 1993,approved and certificated bythe „Bureau Veritas QualityInternational“.

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GEA Messo AG, Bürglistrasse 29, CH-8400 Winterthur, SwitzerlandTelefon +41 52 234 00 00, Telefax +41 52 234 00 99, Email: contact@geamesso.com, www.geamesso.com

GEA Messo AG

GEA Process Engineering FranceKestner Division4, Rue Jean-Pierre Timbaud, BP 80,Montigny le BretonneuxF-78185 Saint Quentin en Yvelines CedexPhone: +33 1 30 14 61 10Fax: +33 1 30 07 18 19www.gea-pe.fr

GEA Messo GmbHFriedrich-Ebert-Straße 134D-47229 DuisburgPhone: +49 20 65 90 30Fax: +49 20 65 90 32 99www.messo.com

GEA Wiegand GmbHEinsteinstraße 9-15D-76275 EttlingenPhone: +49 72 43 70 50Fax: +49 72 43 70 53 30www.gea-wiegand.de

Niro Inc.9165 Rumsey RoadUS-21045 Columbia, MarylandPhone: +1 41 09 97 87 00Fax: +1 41 09 97 50 21www.niroinc.com

GEA Messo AG is part of the ProcessEngineering Division of GEA Group and ofthe Strategic Business Unit Evaporation andCrystallization consisting of the main compa-nies:

� GEA Process Engineering S.A.S (Kestner Division), France

� GEA Messo GmbH, Germany� GEA Wiegand GmbH, Germany� Niro Inc. (Evaporation and Crystallization

Division), USA� GEA Messo AG, Switzerland

The range of activities of GEA Messo AG covers:

� Salt plant technology and supply of completevacuum salt plants

� Plants for concentration of effluents (processwaste streams) and/or recovery of valuableby-products

� Plants for concentration and disposal of fluegas scrubber effluents containing hydro-chloric acid, various salts and impurities

� Concentration and crystallization units andplants for the chemical, metallurgical andfertilizer industry (process streams)

� Plants utilizing various process technologiesfor Chloralkali industry