April 2011 – Steel Times International

Steelmaking

Compact hybrid suspension for BOF convertersA NEW solution for the suspension of BOFconverters combines the proven, maintenance-free ConLink suspension system of SiemensVAI with lamella-type elements mounted belowthe trunnion ring. The result is a space-savingconverter suspension that enables the convertervessel to expand without obstruction. The com-pact dimensions of the Simetal Compact Linkallow the converter capacity to be maximisedfor the available space. The suspension systemis also suitable to retrofit existing converters,and has already been successfully installed onthree converters in the steelworks ofvoestalpine Stahl in Linz, Austria.

Converter vessels are subject to high thermalstresses during operation that lead to substan-tial thermal expansion and deformation. Theconverter is connected to the trunnion ring by asuspension system that has to compensate forthese effects.

Increasing productivity demands and theresulting large converter sizes of today placeenormous burdens on the suspension system.To date, there have been two main technicalapproaches for supporting high suspensionloads: a static suspension system with link ele-ments, and a radially flexible lamella suspensionsystem of compact size.

The Simetal Compact Link combines theadvantages of both of these suspension types by

incorporating vertical lamella elements and hor-izontal links. Depending on requirements, thelinks can be positioned either above or belowthe trunnion ring. As the lamella elements alsoabsorb some of the forces acting horizontally,the horizontal links can be dimensioned small-er as they no longer have to bear all of the hor-izontal forces. Arrangement of the horizontallinks and lamella elements below the trunnionring means that all of the suspension elementsare located in a protected area.

Three LD converter plants in the Linz

The new compactsuspension systemsenables the tap sizeto be increasedclose to 5%

THE BOF converter at the second productionline of the ThyssenKrupp CSA Siderùrgica doAtlântico steel mill started up last November.

Supplied by Siemens VAI MT, the contractincluded a slab caster which made its first castin September.

Overall for the steelworks, Siemens VAI hassupplied two basic oxygen furnaces, secondarymetallurgical facilities, primary and secondarydust-cleaning systems, two continuous slabcasters, and the associated electrical andautomation equipment.

The steelworks is designed to produce 5Mt/yof slab, 60% of which is to go to supply TKS’snew start-up in Alabama, USA and 40% to itsplants in Germany.

The steel mill is located in Sepetiba in state ofRio de Janeiro. Steel is produced in two 330tBOF converters equipped with the mainte-nance-free ConLink vessel-suspension systems,quick-change oxygen lances, pneumatic slagstoppers, sublances and bottom-stirring systems.

The secondary metallurgical plant includestwo ladle-blowing stands for steel homogenisa-tion, a chemical-heating stand, and an RH vac-uum-degassing plant.

The RH tank has a combined oxygen-blow-ing (COB) lance for decarburisation and pre-cise adjustment of the steel quality. A dry-typeprimary dust-cleaning system was used here forthe first time in South America. It is designed torecover and clean 282600Nm3 of converteroffgas per hour. The waste heat from the con-verter offgas is also used to generate steam in aboiler plant. The secondary dust-cleaning sys-tem has a capacity of more than 2.2Mm3/h.

Slabs of widths 800mm to 2000mm, thick-nesses of 200mm to 260mm and lengths from 6to 12m can be cast on the slab casters. A num-ber of technological packages optimise the pro-duction process and ensure that the requiredproduct quality requirements are met.

The technological packages include: LevConautomatic mould-level control; DynaWidth foronline adjustments of the slab width; theMoldExpert system for the monitoring ofstrand-shell friction and automatic breakoutprevention; and the DynaFlex mould oscillatorfor flexible setting of the oscillation parameters.

Easy-to-maintain Smart segments are used inthe straightening zone and the horizontal sec-tion of the slab caster.

Intermediately supported strand rollersensure a long service life. The Dynacs second-ary cooling system provides optimum slab cool-ing, and the VAI-Q system is the basis for qual-ity assurance.

Siemens VAI also installed the automationand process-control system for the slab casters.This enables all operating parameters to beoptimally harmonized throughout the entireproduction process. The entire plant ran in thefully-automatic mode right from the first cast.

The new steel mill of ThyssenKrupp CSA is ahighly efficient production facility located nearBrazilian iron ore deposits. ■

Contact:

Siemens AG, Industry Sector - Industry Solutions Division

Schuhstr. 60, 91052 Erlangen, Germany

web www.siemens.com/industry-solutions

ThyssenKrupp CSA Brazilstarts BOF shop two

Steelworks of voestalpine AG have been outfit-ted with the Simetal Compact Link convertersuspension system. As this solution requires lessspace than the previously installed suspensionsystem, the tapping weights of these converterscan be increased to 180t. This has expandedthe plant’SIEMs steel output from 5.45 to6Mt/y. The insights gained from this first imple-mentation have already been applied to furtherimprove and optimise the system. ■

www.siemens.com/metals

ArcelorMittal

doubles capacity

at João MonlevadeArcelorMittal Monlevade, part of theArcelorMittal Long Carbon Americas Division,is a long product manufacturer with a presentproduction capacity of about 1.2Mt/y of crudesteel. The company is currently carrying out acomprehensive expansion programme at itsJoão Monlevade steel mill located in theBrazilian state of Minas Gerais which will dou-ble capacities throughout the entire processchain. In the course of this programme both ofthe existing 130t BOF converters will beequipped for parallel operation.

Siemens VAI will design and supply the hot-metal desulphurisation station, ladles, deslag-ging stands, the ladle and slag pot transfer cars,and the associated electrical and automationequipment. The material-feeding system willalso be expanded, and its alloying capacity dou-bled. The scope of supply also includes two sec-ondary dust-cleaning systems with cleaningcapacities of 800 000 and 1 000 000m3/hrespectively. Offgas from hot-metal desulphuri-sation, the converters, the hot-metal supply andsecondary steel refining will all be cleaned.

Capacity will be doubled by 2012. ■

www.siemens.com/metals

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April 2011 – Steel Times International

Steelmaking

Vessel Manager’s main display screen allowsusers to observe critical live and historicalinformation

A NEW Vessel Manager’s software and hard-ware that monitors temperature changes overthe entire surface of metal ladles helps assureplant safety by warning of potential break-outsand provides trend data to establish efficient re-lining schedules.

Designed for steel mills and other moltenmetal processes, the system provided by LandInstruments International includes multipleThermal Imaging cameras positioned to view

Robust ThermalImaging Camera hasprotective enclosurefor reliable operationin hostile conditions

A typical five-camera Vessel Manager instal-lation monitors the entire exterior surface,giving a full 360° view of ladle refractorycondition

Monitoring ladle refractory condition for safety and cost control

the entire exterior surface of a ladle.Temperature information is collected each timethe ladle passes a measuring station, allowingassessment of the extent and distribution ofwear to the lining. The system’s software cre-ates actionable records for each ladle.

Vessel Manager data helps prevent two seri-ous problems by:– Accurate statistical measuring of lining

wear to allow managers to set realistic relin-ing schedules, reducing both the cost of too-frequent maintenance and the risk of break-outs.

– Constant recording of temperature changes helps identify ladles that are threatening to fail earlier than predicted, sounding an alarmand lessening risk of plant damage and work-er injury.

By identifying the exact location of unexpect-ed hot spots in a particular ladle, the systemallows some partial re-linings to extend the lifeof the ladle. ■

Contact

Anne Matthews (UK)

Tel +44 01246 417691 e-mail land.infrared@ametek.co.uk

web www.landinst.com/infrared

NEW Zealand based LanzaTech has signed amemorandum of understanding with Posco forthe implementation of its gas fermentationtechnology to convert the steel maker’s COfrom its BOS converters to ethanol and othervalue added products.

LanzaTech uses non food renewableresources to produce ethanol and also 2,3-Butanediol (2,3-BD), a key building block usedto make polymers, plastics and hydrocarbonfuels. It has investment from K1W1 (NewZealand), Khosla Ventures (US) and QimingVentures (China) as well as funding from theNew Zealand and US governments.

LanzaTech chief executive Dr JenniferHolmgren comments: “Posco’s environmental-ly conscious policies are consistent withLanzaTech’s technology vision of reducing thecarbon footprint while increasing energy effi-ciencies at industrial facilities. The proposedlicensing by Posco of our patented microbe andfermentation process fits with our growth strat-egy in Asia.”

Noi-Ha Cho, chief technology officer ofPosco, says gas fermentation technology createsgreater value from by-products of the steelprocess.

“It provides a new way to produce green

energy and it will also contribute to reducingCO2 in steel plants,” he says.

This is the second signing with a major steelcompany. In June 2010, China’s Baosteelsigned an agreement to build a demonstrationplant due to be completed later this year.

LanzaTech has run a pilot plant using itstechnology at NZ Steel at Glenbrook,Auckland since 2008. A demonstration plant isthe last stage before commercial operation.

For further information on the technologyfollow the link:www.steeltimesint.com/contentimages/features/Environment_LanzaTech.pdf ■

Posco and LanzaTech to collaborate on BOSgas to ethanol plant

THE Japan Steel Works (JSW) has received a150t Electroslag Remelting (ESR) plant whichwill be the largest single electrode static meltingESR plant in the world when commissioned.

Supplied by Consarc Corporation, USA, theESR furnace consists of two furnace heads withtwo melt stations, and is capable of melting asingle 150t electrode, or multiple smaller elec-trodes simultaneously, under complete inert gascover. It employs proprietary power systemsdesigned and built by Consarc specifically forthis large scale ESR. The furnace system wasdesigned, manufactured, preassembled for test,

150t ESR claimed as world’slargest refining unit

The world’s largest single electrode ESRplant awaiting shipment to Japan

and shipped from Consarc’s world headquar-ters in Rancocas, NJ USA. JSW plans to put theESR furnace into production in August 2011.

JSW’s Muroran Plant boasts some of theworld’s most modern and technically advancedequipment including a 14kt hydraulic forgingpress. The plant manufactures a wide range offorged and cast products used to support theglobal energy sector. ■

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