MEROS®
MAXIMIZED EMISSION REDUCTION
OF SINTERING

primetals.com

MEETING FUTURE ENVIRONMENTAL
DEMANDS NOW!
WITH MEROS® - MAXIMIZED EMISSION
REDUCTION OF SINTERINGADVANTAGES OF MEROS®:• Highest removal efficiency
for heavy metals, acid gases,
dioxin and other VOCs due tocountercurrent flow injection of
additives• Minimized quantity ofrecirculation dust, therefore
fewer filter pulse-cleaning
cycles and less compressed air
required

YOUR CHALLENGEOUR SOLUTION

Requirements placed on availability,
process quality and productivityof sinter plants are continuously
growing, and can only be met withdesigns suitable for the rugged ironand steelmaking environment. At
the same time, a growing number ofenvironmental regulations necessitate
extensive investment. This especiallyaffects sinter plants with their highquantity of emissions, which has
become a focal point of authorities
responsible for environmental
protection. As plant designers, ourjob is to create concepts that offer
the best possible solution serving
environmental requirements andeconomical necessity simultaneously.

A fully satisfactory, environmentallycompatible solution for the treatmentof the offgas arising during thesintering process has not existed
for a long time. In response to thischallenge, Primetals Technologies
developed the MEROS® process
which stands for Maximized Emission
Reduction Of Sintering. In a series ofsuccessive treatment steps the dust
and harmful metallic and organic
components present in the sinteroffgas are removed to levels previously
unattained with conventional gastreatment techniques. Process
operations and operating parameters
were confirmed during two yearsof performance of the MEROS®
demonstration plant. This was followedby the construction of the world‘s first
MEROS® industrial plant which started
up at the sinter plant of voestalpine
Stahl, Linz/Austria.

2• Minimized mechanical stresson filter bags by using lowpressure pulse cleaning
MEROS® – a dry-type offgas cleaning
process to reduce harmful emissions
from sinter plants• Avoidance of system sticking
due to dry dust recirculation• Controlled and constantprocess temperature as
the basis for efficientdesulfurization with hydrated
lime• Flexible gas desulfurization
with hydrated lime - Ca(OH)2 or
sodium bicarbonate - NaHCO3
as alternative process solution

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MEROS®
GAS CLEANING WITH HYDRATED LIME(VARIANTE A)
Lime andadsorbent dosing

SIMETAL MEROS plantAir, water
Pulse jet cleaning~ 140°C

Booster fan
Static mixer

Sinter plant

Fabric filter~ 100°CStack

Gas conditioning
Additive injection
Residuesilo
By-pass (optional)

Recirculation

MEROS® process - Gas cleaning with hydrated lime

Pulse Jet Filter

PROCESS DESCRIPTIONINJECTION OF ADDITIVESGAS CONDITIONING

PULSE JET FILTERIn the first step, adsorbents such as specially preparedlignite coke and hydrated lime for desulfurization are
injected into the sinter offgas stream in the counter-current
flow direction.In the second step, the gas stream passes
to a conditioning reactor where the gas is moisturized andcooled to a temperature of about 90-100°C by means of an
injected fine mist using dual flow nozzles (water and air).

The injection of additives has two different objectives.
Objective one is the desulfurization of the offgas (DeSOx)
by injection of specific desulfurization powders. Objective
two is the reduction of heavy metals, PCDD/F (dioxins/
furanes) and other toxic organic compounds VOC (volatileorganic compounds).

Special importance has to be addressed to the gas
conditioning reactor. On the one hand temperature peaks
are eliminated to protect the fabric filter bags and on theother hand the gas is conditioned at a desired processtemperature (usually around 90-100°C) for improved
desulfurization.

MAIN BENEFITS

MAIN BENEFITSMain task of the fabric filter is the separation of theparticulate matter transported with the offgas. This dust
consists of primary dust, additives and reaction products.
The dust particles remain on the outside surface of the filter
cloth and the filter cake is built up at the surface of themembrane. When reaching a certain pressure drop over thefilter, a compressed air pulse is activated and the filter cakefalls off the cloth surface into the dust hopper.

This accelerates the chemical reactions required for binding
and removing SO2 and other acidic gas components.In
the third step, the offgas stream passes through a pulse
jet filter equipped with special high-performance fabrics
where the dust and the trapped pollutants are removed. Inorder to enhance the gas cleaning efficiency and to reduce
additive costs, the main portion of the dust is recycled tothe offgas stream after the conditioning reactor. The dust
removed from the system is conveyed to intermediatestorage silos for subsequent disposal or further treatment.

• Perfect distribution of additives by several injection
lances• Special design of reactor inlet and outlet section toprevent clogging, settling and separation of particulates

MAIN BENEFITS• Highest removal efficiency due to countercurrent flow
injection of additives at a high relative velocity• Special designed dual-flow nozzles to generate fine mist

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Beside a perfect distribution of the additives, a highrelative velocity of the injected particles against the gas
flow is needed. A combined injection of the two powders
is realized in counter current direction to the gas flow ata relative velocity far above 30 m/s. To ensure excellent
distribution, several injection lances are positioned inside
the gas duct.

• Set point temperature can be adjusted individually fromthe dust recirculation rate
• Permanently controlled and constant processtemperature ensures reliable desulphurization of off-gas• Highest separation efficiency• Persistent and temperature resistant filter bags suitable
upto 250°C• Low compressed air demand• Minimized mechanical stress on filter bags using low
pressure pulse cleaning• Minimum filter area demand due to 8 or 10 meter lengthof filter bags

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MEROS®
GAS CLEANING WITH SODIUM BICARBONATE(VARIANTE B)
Soda and adsorbent dosing

SIMETAL MEROS plant

Pulse jet cleaning
Booster fan

Sinter plant
Static mixer

Fabric filter
Stack

Additive injection

Residuesilo
Recirculation

By-pass (optional)

Additive dosing/injection

MEROS® process - Gas cleaning with hydrated lime

RECIRCULATION OF DUST

ADDITIVE AND RESIDUE STORAGE

PROCESS DESCRIPTION

Most of the dust separated by the pulse jet filter isrecirculated to the gas stream just behind the gas
conditioning reactor. Doing so, the unreacted parts ofadditives are once again contacted with the offgas andthe effective usage rate is increased which results in an
optimized operation cost figure.

The additives are delivered by tank trucks andpneumatically fed to the additive storage silos. From there
the material is fed to the intermediate gravimetric dosage
bins for further treatment and injection into the raw gas
duct.Parts of the dust separated in the filter hoppers is
not recirculated and conveyed to the residual storage silo.
The residue is transported by a tank truck for external
utilisation.

Depending on the local requirements and conditions, alsosodium bicarbonate can be used as desulphurization agent.
The use of sodium bicarbonate is preferred if highest
DeSOx degrees are required, if a DeNOx plant is necessary(or expected in future) or where land-filling costs are high.
ADVANTAGES OF USING SODIUM BICARBONATE• Desulphurization efficiency more than 95%• Excellent stochiometry close to 1 and decreased amountof residue• Possibility to elutriate the Na2SO4 out of the residuals anddischarge the water into the see• Higher reaction temperature, in case of a DeNOx plantless energy for reheating is required• No water consumption – no cooling is required• Simple process – low investment costs• Less consumption of compressed air
SUMMERIZING, SODIUM BICARBONATE ISFAVOURABLE IF• Highest DeSOx degrees are required

COMPARISON OF SODIUM BICARBONATE AND
HYDRATED LIME FOR USE AS DESULPHURIZATIONAGENTS
Sodiumbicarbonate(SBC)

Hydrated lime
(HL)

DeSOx degree> 95%< 85–90%*

Stochiometricfactor

1.1

1.7–2.0*

Residual amount

~ 70%

100%

Aditive costs~ 180–200%

100%

Temperature
after DeSOx

sinter raw gas
temperature (nocooling)~ 90–100°C

Coke gas
consumption
for DeNOx(if required)60-70% saves
considerablyreheating gas!

100%

*depending on additive quality, sinter gas temperature, conditioning
temperature• DeNOx plant need to be installed either immediately or in
the future• Landfilling costs are high67

THE WORLD‘S FIRST MEROS® PLANT
SINTER PLANT LINZ/AUSTRIAMEROS® at voestalpine, Linz/Austria

A fully satisfactory, environmentally compatible solution
for the treatment of the offgas arising during the sintering
process has not existed up until now. In response to thischallenge, Primetals Technologies recently developed the
MEROS® process. In a series of successive treatment steps
the dust and harmful metallic and organic components
present in the sinter offgas are removed to levels previously
unattained with conventional gas treatment techniques.
After two years of excellent performance of the MEROS®
demonstration plant, the world‘s first MEROS® industrial
plant is now in operation since 2007 at the sinter plant ofvoestalpine Stahl, Linz/Austria.

PLANT DATA
Gas flow
Raw-gas temperature ~650,000 Nm³/h

Gas conditioning tower

MEROS® at voestalpine, Linz/Austria

EMISSION REMOVALPROJECT SCHEDULE AND FURTHER IMPLEMENTATIONSTEPS

SO2 removal

130°C (120–160°C)

Filter area

~ 19,000 m²

Clean-gas dust content

Cooling-water flow

8-30 m³/h

NOx (as NO2)

Sinter gas cooling bys

2-50°C

Additives:
Hydrated lime(original
process design)~ 330 kg/h

Sodium bicarbonate(current operation practica)~ 500 kg/hLignite~ 60 kg/h

Dust recirculation> 50% (current operation
practice)*< 5 mg/Nm³< 150mg/Nm³

Hg

> 97%

Pb

> 99%

• Start-up: August 2007

• Installation of SCR - DeNOx plant: 2012
SCOPE OF SUPPLY & SERVICES – PROCESS TURNKEY• Project management

HCl

> 92%

HF

> 92%

Organic components
Dioxin (PCDD/F) emissions• Start of erection: October 2006

• Conversion to sodium bicarbonate process: 2011

Heavy-metal removal efficiency

Removal efficiency of acidic gases~ 10 t/h• Award of contract: March 2006

< 0.1 ng TEQ/Nm³

VOC (condensable)> 99%• Basic and detail engineering• Procurement of all equipment• Process control and automation level 1• Erection execution of plant• Supervision of erection and commissioning* Technically up to 98% SO2 removal is possible

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SELECTIVE WASTE GAS RECIRCULATIONENERGY EFFICIENCY FOR SINTER

BAG FILTER CONTROLSMART BAG FILTER CLEANING FORENVIRONMENTAL PLANTS IN THE METALSINDUSTRYFUNCTION
Cost-efficient production in accordance withenvironmental requirements forms the basis forcompetitive steelmaking. Thanks to intelligent, fast androbust electronic modules, the bag filter control unit
optimizes bag filter operation, featuring a significantly
reduced cleaning air consumption as well as thedetection of defective cleaning valves. This stand-alone
self-monitoring package can be easily implemented inexisting plants, thereby ensuring completely automatic
operation. A standard bag filter operates without anyenergy optimization, based on fixed cleaning cycles
where the cleaning valves purge compressed air into
the filter bags. A malfunction of a cleaning valve canonly be detected manually through acoustic checks,
which are both time consuming and cost intensive. Mostof the cost-intensive compressed air is wasted, because
the cycle time is not adjustable in the system.

Waste-gas recirculation hood

Selective waste-gas recirculation system

In order to save CAPEX and OPEX for the MEROS® Plant
Primetals Technologies recommends to combine theadvanced gas cleaning investment with the Selective Waste
Gas Cleaning system wherever technically possible.

MAIN BENEFITSFIELD OF APPLICATION

MAIN BENEFITS• Waste gas volume by up to 50%

All kind of dedusting systems with bag filter cleaning• Specific solid fuel consumption decreased by up to 10%

OUR SOLUTION• Automatic control of the entire bag filter features highefficiency of the bag filter cleaning process• Decreased investment and operational costs for wastegas-cleaning plant

An optimized bag filter control is the major precondition
for cost reductions. Using a differential pressure
measurement between bag filter inlet and outlet, and theactual volume gas flow, an optimal cleaning cycle mode is
automatically selected by the bag filter control unit. A fastand reliability electronic module with MOS-FET technology,
which additionally features self-monitoring functions,controls the cleaning valves. The duration of the open timefor each cleaning valve can be adjusted, thereby reducing
the compressed air consumption to a minimum.

SELECTIVE WASTE-GAS RECIRCULATION SYSTEM
Primetals Technologies has developed and implemented a
new technology that enable environmental emissions fromsinter production to be reduced. This has been achieved
with the introduction of a selective waste-gas recirculation
system in which the offgas from selected zones of thesinter machine is mixed with hot cooler off-air and is thenrecirculated to the sinter strand.

• Lower CO2 emissions (reduction by up to 10%)• Lower emissions freight of SOx, NOx, PCDD/PCDF andheavy metals• Extended battery service life

• Pre-tested technological package including HMI, softwareand hardware• Powerful electronics replace conventional relays• Short implementation and commissioning time in new orexisting bag filters• Short amortization time and high return of investment• Energy savings due to reduced cleaning air consumption• Reduction of maintenance costs

The selective waste gas recirculation system enables
emission reductions in sinter production to previously
unattained levels. Thanks to the advanced technology, theoffgas from selected zones of the sinter machine is mixed
with cooler off-air and/or ambient air and re-circulated tothe sinter machine. The result is a significant reduction of
the specific offgas volume by up to 50%.
Specific investment and operating costs for gas-cleaning
facilities can therefore be kept at acceptable levels. The
selective waste gas recirculation system from Primetals
Technologies can be installed in existing or greenfield
plants.

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PULSE JET FILTERS
CLEAN SOLUTIONS FOR DUSTHANDLING

Hoppers with steep inclination avoid dust deposits

THE ENVIRONMENTAL PLANTSINSTALLED BY PRIMETALS TECHNOLOGIES COMPRISE• Pulse jet bag filter units and reverse air bag houses• EAF dedusting comprised of watercooled ducts, dropout boxes, quenching towers, forced draught coolers,
cyclones, canopy hoods, mixing chambers, filters, fansand stacks• AOD dedusting comprised of watercooled stacks, forced
draught coolers, canopy hoods, filters, fans and stacks

Carinox, Belgium, 2005

OUR PULSE JET FILTERS ARE CHARACTERIZED BY• Standard filters designed for low and easy maintenancein a steel shop environment• Modular filter design, which permits future extensions
with add-on components• Dramatic reductions in installation times due to themodular design of prefabricated panels, hoppers andfilter heads• Noise reduction, dog and elephant houses• Accurate blowpipe positioning with centering on theventuris, which ensures long bag life

• DeS dedusting comprised of moveable hoods, cyclones,
filters, fans and stacks• CFD-modelled filter casing for heavy particle separationand optimized flow distribution through bags

• Dedusting systems for the glass and ceramic industry• Low energy consumption due to the cast-aluminumclassic venturi situated on top of the bags, which provide
an efficient secondary air in-draught

As a state-of-the-art system integrator for EAF dedusting
equipment, Primetals Technologies offers comprehensive
in-house solutions for primary and secondary off-gas
treatment in the field of EAF steelmaking.
THESE PROVEN PRIMETALS TECHNOLOGIES DEDUSTING
SOLUTIONS ARE CHARACTERIZED BY• Advanced simulation tools• Low energy consumption using straight blowpipes, which
eliminates elbow losses• Low energy consumption and pressure loss through thefilter casing, due to an optimized gas flow, large venturi
diameters and maximized damper dimensions• Modular design pulse jet filters• Fully automatic filter cleaning with no moving parts on
the inside of the filter• Proven water-cooled duct design• Filter cleaning operation in either online or offline mode

• Proven quenching tower design• Filter cages, which are designed to protect the bags andallow them to be walked on after installation• Proven forced draught cooler design• Custom-made solutions• “Fit-for-use” applications• Highest flexibility

Pulse jet valve arrangement with noise cover• Fully standardized service interchangeable parts, which
are commercially available worldwide for the entire filter
range

Venturi valve hall

REFERENCE PLANT
MAANSHAN IRON AND STEEL COMPANY,
P.R. CHINA

After two years of operation of the MEROS® demonstration
plant and one year of exellent performance of MEROS®
commercial plant at voestalpne Stahl, Linz/Austria, theworld‘s second MEROS® industrial plant was awarded by
Maanshan Iron and Steel Company, P.R. China in the year
2008.

520,000 Nm³/h~ 140°C (120–160°C)

Filter area

~ 16,400 m²

Cooling-water flow

8-30 m³/h

Sinter gas cooling by

20-50°C

Additives:
Hydrated lime
LigniteDust recirculation~ 1,000 kg/h
~ 60 kg/h~ 8 t/h

EMISSION LIMITS
SO2 removal
Clean-gas dust content

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PROJECT SCHEDULE• Award of contract

March 2008

• Start of erection

Spring 2009

• Start-up 		

Summer 2009PLANT
UPGRADES

MAINTENANCESERVICES

BENEFIT FROM OVER 50 YEARSOF EXPERIENCELOW INVESTMENTS FOR
STATE-OF-THE-ART
TECHNOLOGY

ON-AND OFFLINE
MAINTENANCE AND REPAIRSERVICES

Decades of experience
worldwide in design,
manufacturing, and commissioning as well as consultingof metallurgical plants ensureeach client with innovative
modernizations and mechatronicsolutions for its processing chain.

With wide-ranging international
network of customer support
experts and worldwide repair
and maintenance workshops,
Primetals Technologies is yourideal single source partner for
maintenance services.

SCOPE OF SUPPLY & SERVICES• Project management

PLANT DATA

Raw-gas temperature ~OPERATIONALSUPPORT

Comprehensive services formetallurgical plants, fromsupply of original manufacturer
components, spare and wear
parts to consulting, technicalassistance and training.

MEROS® at Maanshan Iron and Steel Company, P.R. China

Gas flow

LIFE CYCLE SERVICES FOR YOUR PLANT> 80% / < 200 mg/Nm³• Basic engineering of entire plant• Supply of mechanical and electrical key-equipment• Process control and automation level 1• Supervision of erection and commissioning

With a portfolio consisting of operational support, plant
upgrades, and maintenance services you can focus on yourcore business while Primetals Technologies assures yourplant’s optimum performance.
Fast, reliable, and experienced service and support for the
metallurgical industry Primetals Technologies strives to bea long-term lifecycle partner dedicated to your success. We
offer a full range of services across the entire lifecycle ofyour plant, including consulting and technical assistance,
directly from a single provider. Our service portfolio ranges
from a spare parts service available at just the right time
to advanced staff training and technical support, upgradesof components and plants to be technical up to date;also from repair service of key components for a longer
lifecycle, to online and offline maintenance. Our services
reduce cost, increase productivity, improve product quality,and ensure safety.

< 5 mg/Nm³

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Primetals Technologies Austria GmbHA Group Company of Mitsubishi Heavy Industries

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Brochure No.: T01-2-N081-L4-P-V3-EN
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