Sinter Plant

The purpose of the sinter plant is to process fine grained raw materials into a coarse grained iron ore sinter, ready to be charged to the blast furnace. Sintering of fine particles into a porous clinker – sinter – is necessary to improve the permeability of the burden, making reduction easier. A high quality sinter has high reducability, which reduces the intensity of blast furnace operations and reduces coke demand. 

In the sintering process a blend of different ores, ferrous containig materials – such as flue dust  – and fine coke particles (known as coke breeze) is deposited on a large travelling grate. The coke at the top of the blend is ignited by gas burners, that can be fueled by coke oven gas, blast furnace gas, or natural gas. As the grate moves, air is sucked from the top through the mixture, enabling combustion through the entire layer and complete sintering – where the temperatures may reach 1300 – 1480 oC. At the end of the strand, the material is cooled by air and finished sinter is size-screened.  

Sinter PlantSchematic

Sinter PlantTechnologies & Measures

Technology or MeasureEnergy Savings PotentialCO2 Emission Reduction Potential Based on LiteratureCostsDevelopment Status
Waste Heat Recovery in Sinter Plant

Japanese flag In Japanese plants 120 and 170 kg steam at 20 atm (equaling 0.34 GJ/t-sinter and 0.48 GJ/t-sinter) are recovered from sinter coolier and sinter machine proper, respectively. Electricity production from these units were 20kWh/t-sinter and 30 kWh/sinter, respectively (JASE-W, 2012)

Japanese flag

 Steam generation of 0.25 GJ/t-sinter is reported in other Japanese plants (NEDO, 2008)

EU Flag Fuel savings up to 0.55 GJ/t-sinter, and increased electricity generation of 1.4 kWh/t-sinter are reported from a  retrofitted plant in Netherlands (US EPA, 2010. p. 13)

CO2 reductions will result due to reduced fuel consumption in the sinter machine and/or for electricity production. 

Reported retrofit capital costs vary between $3/t-sinter (APP, 2010. p.17) to $4.7/t-sinter (US EPA, 2010. p.13).

This technology is regarded to have payback times in the range of 3 to 5 years. 

Commercial
Improved Process Control and Quality Assurance

This technology may result in savings of 2-5 Percent energy use, approximately equal to 0.05 GJ/t-sinter. (US EPA, 2010. p. 14)

US flag Emissions can be reduced by 5 kg CO2/t-sinter (US EPA, 2010. p. 14).

Capital costs were estimated to be $0.21/t-sinter (US EPA, 2010. p. 14).

Commercial
Improved Ignition Oven Efficiency with Multi-Slit Burners

Ignition energy can be reduced by approximately 30% (NEDO, 2008. p.66). 

Emissions were reduced due to lower energy consumption.

Commercial
Emissions Optimized Sintering

EU Flag In a plant in Netherlands, installation of EOS reduced coke breeze consumption by 12 kg/t-sinter (20% reduction).  Lower reductions (~ 6kg/t-sinter) are to be expected in plant running at higher baseline efficiencies. The system increased electricity consumption by 3 - 8 MJ/t-sinter (IPPC, 2009. p. 177). 

EU Flag In a plant in Netherlands, CO2 emissions were reduced by 31% with the use of this technology (IPPC, 2009. p. 177). 

Investment cost at sinter plant of Corus, Ijmuiden was €17 million with 1.2 MNm3/h waste gas flow from three sinter strands. The technology provided yearly savings of €2.5 million. (Lower savings are estimated in other parts where the coke breeze costs are lower).Commercial
Selective Waste Gas Recycling - EPOSINT Process

Coke conusmption and ignition gas consumption is reduced by 2 - 5 kg/t-sinter and 10 MJ/t-sinter, respectively. Electricity consumption increases.  

The technology reduces Up to 40% Off-gas volume. Abatement potential of specific NOx emissions is about 25 - 30%.

A plant with existing waste gas system and a suction area of 250 m2 was retrofitted for €15 million.  

In 2007 the system was installed in two sinter plants in Belgium with suction areas of 175 and 498 m2 at a cost of €14 million and €27.3 million, respectively. 

Commercial
Improved (Segregated) Charging of Materials

Energy consumption is reduced by around 79 MJ/t-sinter due to reduced coke consumption. Productivity increases by around 5% (NEDO, 2008. p. 63). 

In a Japanese sinter plant with 1 million t/y capacity, installation of this system costed ¥80 million for equipment and ¥30 million for construction.  With a coke price of ¥16/kg-coke, equipment cost was recovered in 1.8 years, and total costs were recovered in 2.4 years (NEDO, 2008. p. 63). 

Commercial
Low Emissions and Energy Optimised Sintering Process

Coke breeze consumption can be reduced by 5 - 7 kg/t-sinter.  As the system requires extra electricity to run the additional fans, the net energy saving is approximately 10 MJ/t-sinter (12.5% of the fuel demand). 

Significant reductions in NOx, SOx, HCl, HF and CO emissions are achieved.  CO2 emissions are also reduced due to reduced coke demand.

 

Investment cost was around €14 million.

Commercial
Sectional Gas Recirculation

A 92 MJ/t-sinter energy saving was achieved - as compared to a system with desulphurization plant), corresponding to 6% reduction in coke consumption. Electricity consumption increases due to additional fans.

A slight decrease in NOx emissions of about 3% is reported.

European investment costs for the gas recycling system were quoted at €8-10 million in 1997, excluding deNOx, deSOx and other abatement equipment (IPPC, 2012. p. 180)

Commercial
Leakage Reduction in Sinter Plant

Reducing air leakage from sinter plant reduces fan power consumption by approximately 2.7-3.6 kWh/t-sinter (0.011-0.014 GJ/t-sinter) (US EPA, 2010. p. 14).

US flag Emissions reduction of 2.0 Kg CO2/t-sinter is estimated (US EPA, 2010. p. 9).

Retrofit capital Cost is $0.14/tonne sinter (US EPA, 2010. p. 14).. 

Commercial
District Heating Using Waste Heat

In Korea recovered heat from two sinter machines were used to provide 800 TJ/y district heating energy to 5000 inhabitants (NEDO, 2008. p. 18).  

Fossil energies such as LPG/LNG are substituted resulting in reduced emissions.

Investment for the Korean plant was roughly $22.3 million.

Commercial
Curtain Flame Ignition System

This technology reduces the specific gas consumption by 30% to 50%.

CO2 emissions reductions of approximately 20 000 t/y are expected.

Indian flag In an Indian plant annual savings of around Rs.150 million (US $ 2.7 million) has been realized.

Commercial
Utilization of Waste Fuels in Sintering

Energy savings of around 0.18 GJ/tonne sinter were reported from European applications. 

US flag Emissions reduction of 19.5 Kg CO2/t-sinter can be achieved.

One plant reportedly developed a waste recovery and waste injection system, at a cost of about $25 million, to recycle 180 000 t/y of  various materials. Capital costs were estimated to be $0.29/t-sinter. The payback time was estimated as 0.5 years (US EPA, 2010. p. 15) 

Commercial
Wood Char in Sintermaking

A substitution of around 20% of coke breeze with charcoal in sintering plants is technically feasible.

Charcoal is Greenhouse neutral i.e. CO2 liberated in the sintering process is absorbed By the next crop of growing trees.

 

Cost of Charcoal production is being reduced by using "Cheaper Cuts" i.e. the leaves and the twigs of Malle Trees.

Demonstration
Pelletized Blast Furnace Dust

Significant increase in the substitution ratio makes it possible to save corresponding amount of fuel in sintering.

Commercial
Control Modules

This technology minimizes sinter plant and Blast Furnace energy requirements

Reduction in emissions is expected.

Costs are reduced.

Commercial