Features

Purification of

Acetonitrile

End Purification with

Suspension Crystallization

• Highproductpurity-ThehighestpurityHPLCgradeacetonitrile available on the market today.

• Wasteproductrecovery-Wastedisposalvolumesarereduced and valuable product is recovered.

• Feedstock-Operatesonarangeoffeedstocks.Whenrelativelypurefeedisavailablethespecificimpuritycompositionisirrelevant.

• Simplifieddesignandcontrol–Thesystemissuppliedasaskidmountedcrystallizationandseparationunitincludingrefrigeration.

• Economics-Theoperatingcostsaresignificantlylowerthan other separation techniques. The production costs(including capital, utilities and maintenance) for thiscrystallizationunitarelessthanEuro1perliterpurifiedproduct.

GEA Messo PT can provide assistance in determining theoptimumconfigurationandcostinformationforyourspecificcircumstances.

ApplicationThegrowth inconsumptionofacetonitrileasHPLCsolventand reagent in pharmaceutical synthesis has not onlyincreasedthedemandforthischemicalbutalsotheneedfordisposalofthespentsolvent.Thesmallestamountofimpuritiescansignificantlyaffectthequality of thefinalproducts. Therefore, ultra-pure startingmaterials are essential. Most of the acetonitrile producedtoday comes as a by-product from the production ofacrylonitrile.Anothersignificantsourceofthisproductcanbe found in the waste of universities, research labs andpharmaceuticalproductionfacilities.Thesestreams,althoughgenerallyquitepure,arestillconsideredhazardouswasteandare bound for incineration in licensed disposal centers.Crystallizationcanprovidetheselocationswithacostefficientmethodtorecoverthisproductasultra-pureacetonitrile.Awaste stream of relatively pure feed stockwith between98wt% and 99wt% acetonitrile can easily be upgraded toproductaround99.99wt%(thehighestpurityavailable)withsuspension crystallization. This method offers an efficientmeanstoreducewastedisposalcostsandprovidesavaluableproduct.Thesolid-liquidphasediagramfora solutionofacetonitrileand water is shown below. Unlike distillation techniques,suspensioncrystallizationprovidesthepossibilitytoseparateultra-pureacetonitrilecrystalsinasinglestep.

Crystallization is a proven industrial purification techniqueand GEAMesso PT has been active in its application on avarietyofproductsforover30years.Acetonitrilepurificationis justonenewapplications for this technology. Please seereverse page for a general description of our crystallizationprocess.

GEA Process Engineeringengineering for a better world

Process Description – The melt crystallizationprocessiscarriedoutinanindustriallyprovenscrapedsurfacecrystallizerwherefinalpurification iscompleted in theGEAMessoPTwashcolumn.Thefeedproductiscooledinsidethecrystallizerwherepartof theproduct isconverted intopurecrystal solids leaving the impurities concentrated in theresidualmotherliquor.

The crystallizer consists of a jacketed vesselwith a rotatingscraper assembly. Evaporating refrigerant or a secondarycoolantintheouterjacketcoolstheinnerwallofthevessel.Thescrapersweepsthewallsurfaceandpreventsbuildupofcrystals to maintain a clean heat transfer surface andcontinuoussupplyofproductcrystals.

Each individual crystal provides growth surface that canabsorb the supersaturation causedby cooling theproduct atthesweptsurface.Withbillionsofindividualcrystalspresent,thiswillprovidenearidealgrowthconditionsandensuretheproductionofultra-purecrystals.

TheGEAMessoPTwashcolumncompletestheseparationofthis mixture of pure product crystals and residual motherliquor.ThisseparationisbasedonGEAMessoPT’spatentedwashcolumntechnologyandisanessentialcomponentinthispurificationprocess.The crystal slurry is compressedwithin the GEAMesso PTwashcolumntoremovemostofthemotherliquorandformapacked crystal bed. This bed consists of the pure productcrystalssurroundedbysomeresidualmotherliquor.Thenewcrystalsenteringthewashcolumnwillforcethebedtowardthe scraper assembly at the opposite end. The scraperdisintegratesthecrystalbedandacirculationpumpprovidesmeltedproducttoreslurrythecrystals. Thecirculationflowcarriesthecrystalstoaheatexchangerwheree.g.steamoranyother heat source provides the heat necessary to melt thecrystals.Themeltedproductcanthenbedischargedtoproductstorage.

Themeltedproductintherecirculationstreamcountercurrentlywashestheresidualmotherliquorfromthepackedcrystalbedasitmovesthroughthewashcolumn.Thelengthofthecrystalbedprovidesanextremelyefficientwashzoneforremovalofanyremainingimpuritiesinthemotherliquorensuringultra-pure product. Unlike other solid/liquid separation devicesoperating with a much shorter bed depth, the wash liquidforms an internal reflux loop and is therefore recovered asrecrystallized product in themelt circuit instead of leavingwiththemotherliquor.

Experience – GEAMessoPTisatechnologyorientedengineering company with over 40 years experience in thedesignandexecutionofcrystallizationplantsworldwide.Westarted by crystallizing water from liquid food products in1973 and since then have built and installed over 120purificationunitsaroundtheworldincludingapplicationsforwater, PX, PDCB, phosphoric acid as well as many otherclassifiedorganicchemicals.

Newdevelopmentsinprocesstechnologiesposenewchallengesevery day which require innovative and low-cost solutions.Practical orientation and customer requirement play a vitalroleinthisconnection.GEAMessoPTconsistentlyorientatesitselftowardstheneedsofthecustomer.GEAMessoPThasbeencertifiedaccordingtoDINISO9001standardsince1996andsince June2003 the ISO9001:2000standards were implemented following an audit by theinternationalbureauLloyd’sRegisterQualityAssurance.

Next Steps –On-sitedemonstrationofthistechnologyispossibleinvariousconfigurationsusingGEAMessoPT’spilotplants.Formoreinformationregardingthistechnologyandyourspecificconfigurationrequirementspleasecontactusat:info.niropt.nl@gea.comorphone+31.736390390.

GEA Messo PTDe Beverspijken 7b, 5221 EE ‘s-Hertogenbosch, The Netherlands Tel +31 73 6390 390, Fax +31 73 6312 349 info.niropt.nl@gea.com, www.gea-messo-pt.com TS05.052012-H