DOPOL® '90 preheater - ThyssenKrupp Resource Technologies

DOPOL ® ’90 preheaterand PREPOL ® calcining system.A companyof ThyssenKruppTechnologiesPolysiustk

For every requirement an optimally customisedDOPOL ® / PREPOL ® concept.Innovation is at the centre of the Polysius companyphilosophy. This means purposive innovationas an answer to concrete requirements ofthe industries we serve.In the case of the cement industry, today'srequirement profile for the manufacturing processis directed at high production capacitieswith low operating and capital expenditure.For this reason, multistage cyclone preheaterswith integral calciner and tertiary air duct areindispensable components of modern kiln lines.Polysius offers preheater/calciner conceptsthat are innovative and nevertheless technicallymature for the production of white and greycement; for new plants as well as plant conversions,and tailored to the desired productioncapacity – no matter whether this is less than1,000 or more than 10,000tonnes per day.The heat produced by theburning process in the rotarykiln and calciner is used forpreheating the raw material.The preheating and extensiveprecalcination of the rawmaterial shorten the burningprocess.The high degree of heat utilisationreduces the fuelrequirement and the capitalexpenditure for the rotary kiln.Moreover, it is possible to uselow-priced substitute fuels andmaterials in the calciner and topositively influence the NOxand CO emissions – an additionalplus point for operatingeconomy and environmentalcompatibility.To assure correct dimensioningof the various preheater/calcinersystems, the properties ofthe raw materials and fuels aretested in the central researchcentre of the Polysius Group.This ensures that all thesystems and plant componentsare optimally harmonised.DOPOL ® ’90: the economical preheater generation:The number of cyclone stagesis selected to suit the individualapplication.As a rule, the throughput andmoisture content of the rawmaterials and fuels, which haveto be dried by the remainingexhaust gas heat, decidewhether 2, 3, 4, 5 or 6 cyclonestages are used. The cyclonesand gas ducts have a refractorylining, which keeps the radiationlosses low (below 2 %of the heat consumption).Due to to the optimum flowdynamicdesign, the pressuredrop of the preheater system issmall, minimising the electricalenergy requirement for theexhaust gas fan.The high collection efficiencyof the cyclones ensures thatthe exhaust gas has a low dustcontent.5-stage DOPOL ® ’90 preheaterincluding PREPOL ® -CC-MSCcalcining system for 2,600 t.p.d. ofcement clinker in Spain.Advantages of the DOPOL ® ’90 concept:x Minimal power requirement due to highdegree of heat recuperation and low pressuredrop.x High efficiency – low heat consumptiondue to high cyclone collection rate anduniform meal distribution over the gas ductcross-section.x High availability thanks to the proven,reliable design and construction.Special PREPOL ® calcining systems for differentrequirement profiles.The calciner fulfils the functionsof heating-up and calciningthe raw material and ofburning the supplied fuel. Theburning of the different typesof fuel takes significantly moretime than heating-up andcalcining the raw meal and istherefore the determining factorfor the dimensioning of thecalciner.In addition to assuring completecombustion of the fuel,the calciner has to function5-stage DOPOL ® ’90/PREPOL ® -ASpreheater calciner combination in Saudi Arabia;designed for a daily production rate of3,500 tonnes of grey cement clinker.with great flexibility, in orderto cope with the wide range offuel grades used (from highlyreactive to extremely unreactive).Today, great importance isplaced on systems incorporatingprimary measures for emissionreduction, and this trend isincreasing.For such requirements Polysiushas developed the PREPOL ® -MSC-CC system in addition tothe proven PREPOL ® -MSCcalciner. This system permitsthe use of unreactive fuels andsimultaneously reduces thenitrogen oxide emissions.The Polysius PREPOL ® -AS calcinerprogramme (AS standsfor Air Separate; a conceptwhich all PREPOL ® types share)thus includes a selection ofversions, -CC, -MSC and-MSC-CC, in order to optimallyfulfil individual requirementswith regard to operating reliability,product quality, flexibilityand emission reduction.

4,000 t.p.d. grey cementproduction line in Vietnam with5-stage DOPOL ® ’90 preheaterand PREPOL ® -CC system(for anthracite firing).Advantages of PREPOL ® calcining systems:x uniform kiln operation, thanks to extensive precalcination of the raw meal,x long refractory lining service life in the rotary kiln, as a result of the low thermalloading,x minimal coating formation in the preheater, due to the low circulation of alkalis,x low pressure drop in the preheater because of the optimum flow-dynamic design ofthe calciner, andx superior economy of operation thanks to the high fuel flexibility.The first of two 10,000 tpd kiln lineswith 5-stage DOPOL ® ’90 and PREPOL ® -MSCcalciner to be constructed in China.3-stage DOPOL ® ’90 withPREPOL ® -MSC-CC calcinerin the USA; output: 2,700 tpdof grey cement clinker.White cement production linein Spain with 6-stageDOPOL ® ’90 preheater.

PREPOL ® -CC with separatecombustion chamber (picture at top).Split tertiary air supply of thePREPOL ® -MSC process.PREPOL ® -CCIn order to improve the burnout ratewhen using non-reactive fuels,Polysius developed the PREPOL ® -CC(Combustion Chamber). The calciningsystem achieves outstanding resultswhen raw materials with poorly combustibleconstituents are used and incases where high internal alkali cyclesmay arise in the kiln plant due to thefuel and raw material compositions,resulting in impairment of thecombustion.The separate combustion chamber,which is connected to the calciningloop by a gas duct, is the main featureof the PREPOL ® -CC. Providing thepossibility to influence the combustiontemperature, it ensures calcinerefficiency when using solid fuels.PREPOL ® -MSCThe PREPOL ® -MSC calciner is thestandard calcining system for reducingNOx emissions. The MSC (Multi StageCombustion) process is based on thesplit feeding of fuel, tertiary air andraw meal. The effect is only achievedby means of this special mode ofoperation. This means that the operatingcosts are no higher than those ofclassical calcining processes.At the numerous MSC plants installedall around the world it has beenSelection matrix for calcinersproved that, depending on the fuel,the NOx emission rate is reduced byup to 50 %.PREPOL ® -MSC-CCTo reduce operating costs, it has todaybecome common practice to operatethe calciner with fuels which have poorburnout behaviour, as well as withsecondary fuels.At the same time, many plants haveto observe regulations stipulating lowPREPOL ® type AS CC MSC MSC-CCFuelpropertiesFlexible change of fuelEmission reductionSuitability for bypassHigh ash content xx xx xx xxNon-reactive x xx x xxx xx xx xxX X xx xxxx xx x xxx Very suitable x Well suited X SuitablePREPOL ® -MSC-CCsystem installed inthe USA.limit values for nitrogen oxide emissions.To enable nitrogen oxide reductionwhile maintaining the flexibility offuel usage, Polysius developed thePREPOL ® -MSC-CC process.This combines the combustion chamberof the PREPOL ® -CC process withthe split introduction of fuel, tertiary airand raw meal that is characteristic ofthe PREPOL ® -MSC process.The kiln inlet is equipped with a kilninlet burner for reducing the nitrogenoxide created in the clinkering zone ofthe kiln. The greater portion of the fuelis fed into the combustion chamber.That leads into the MSC calciner,where there is a further split infeedingof air and raw meal.