Guidelines for Selecting Pellet Plant Technology I. Cameron, M. Huerta, J. Bolen M. Okrutny, K. O Leary

Transcription

1 Guidelines for Selecting Pellet Plant Technology I. Cameron, M. Huerta, J. Bolen M. Okrutny, K. O Leary AusIMM, Iron Ore Conference, Perth WA July 2015

2 Introduction 2 The availability of lump ore and sinter fines is declining; lower grade iron ore resources must be finely ground to upgrade Fe content to acceptable levels. Eventually, new investments in pelletizing capacity are required to bring Fe concentrates into the steelmaking value chain. The straight grate (SG) and grate kiln (GK) are the only two commercially proven processes. Hatch compared both technologies to help investors better understand how best to pelletize concentrates.

3 Contents 3 Iron Ore Pelletizing Technologies Plant Capacity Fuel Options and Energy Consumption Pellet Product Quality Capex and Opex Environmental Performance Summary

4 The Growth of Iron Ore Pelletizing 4 World Pelletizing Capacity (Mtpa) Regional growth since 1950 China Middle East Rest of Asia / Australia Europe CIS South America North America Year Iron ore pelletizing has grown since its origins in 1950 s and accelerated in recent times. With depletion of high quality DSOs and sinter fines, global pellet feed production will substantially increase. Pelletizing capacity will continue to grow to supply direct reduced iron plants and blast furnaces. Usage of pellet feed at sinter plants will increase.

5 5 Straight Grate (SG) and Grate Kiln (GK) The Straight Grate (SG) pelletizing process The Grate Kiln (GK) pelletizing process

6 New Emerging Technology: Circular Pelletizing Technology (CPT) 6 Primetals Technologies Circular Pelletizing Technology (CPT) Alternative to SG and GK. Essentially a SG induration furnace arranged in a circle to reduce the plant footprint. Current plant sizes on offer to 3.0 Mtpa. First plant under construction in India.

7 Iron Ore Mineral Pelletized 7 Pelletizing capacity by iron ore mineral World Pelletizing Capacity (Mtpa) Other Ores Hematite Magnetite + Hematite Magnetite The SG technology is proven for magnetite, hematite and mixed ores. The GK is proven for magnetite ores and mixtures of magnetite and hematite; less experience with hematite ores than the SG. 0 SG GK

8 Pellet Plant Capacity Increase Since Annual Capacity of Individual Pellet Lines (Mtpa) SG Improvements GK Improvements SG/GK Improvements Carbon Addition Cooler Recoup Automation Systems Coal Fired Kiln Deep Bed Hearth Layer Bin Separation Double Deck Roller Screen Hyper Activation Reduced Air Leakage Year High Pressure Grinding Rolls Roller Screen Expert Systems Advanced Process Control Fans with Variable Frequency Drives Mathematical Models

9 Fuel Options Ability of SG and GK to use various fuels 9 Fuel SG GK Gaseous Fuels Liquid Fuels Solid Fuels, such as coal Solid Carbon Addition to Hematite Concentrate Limited

10 Energy Consumption 10 Thermal energy consumption for selected pellet plants Electricity consumption for process fans Magnetite Magnetite Mag Hem Mag Hem Magnetite Mag Hem Magnetite GK SG Thermal Energy Consumption (MJ/t pellet) Technology Typical (kwh/t) Lowest Reported (kwh/t) SG GK

11 Pellet Product Quality 11 Both SG and GK produce quality fired pellets for BF and DR applications. Fired pellet quality depends on ore type, end user demands, type and quality of fluxes and binders, balling technology, screening equipment, etc. The GK produces fired pellets with more uniform physical strength due to the nature of material flow in the rotary kiln that exposes all green pellets to the peak firing temperature. The SG generates less fines due to the absence of transfer points and little relative movement/abrasion between pellets and furnace parts. Both SG and GK report experience with organic binders; more data is needed to fully understand how best to use organic binder and produce top quality pellets.

12 Capex and Opex Comparison 12 Capex Comparison SG and GK Opex Comparison SG and GK 100 Cost Items SG GK Relative Capital Cost Iron Ore Concentrate similar similar Additives/Binder similar similar Fuel Electricity Water similar similar Refractory Other Consumables similar similar Labour similar similar 0 Straight Grate Grate Kiln Maintenance Overall similar similar

13 Environmental Performance 13 Air pollutants of concern are dust, SO x, NO x and greenhouse gases (GHG). Both technologies use ESPs or bag houses for dust control. Newer plants are considering de-s equipment to reduce emissions. The SG can utilize ultra low NO x burners in a separate combustion chamber with controlled atmosphere; this approach is not possible in the GK. Low NO x burners can be used in the GK, but the ultra low levels projected for the SG are probably not possible for the GK. GHG production, particularly CO 2 is directly related to the type and amount of fossil fuel combusted and the calcination of fluxes.

14 Overall Comparison SG and GK 14 Variable SG GK Remarks 1) Iron Ore Mineral a) Hematite limited yes use b) Magnetite yes yes c) Hematite/Magnetite Mixture yes yes 2) Unit Capacity a) 3-7 Mtpa yes yes b) 7-9 Mtpa yes no 3) Fuel Type a) Natural Gas yes yes b) Fuel Oil yes yes c) Pulverized Coal no yes d) Carbon Addition to Hematite Ore Mix high amount limited use GK is best suited for magnetite and magnetite/hematite mixtures while SG is suitable for all minerals. GK has not demonstrated unit capacities beyond 7.0 Mtpy. SG has not demonstrated operation with pulverized coal while GK can operate will all fuels. SG can operate with high amounts of carbon additions to hematite ore mixes whereas the use of GK for this application is limited. Legend: Competitive advantage No advantage/disadvantage Disadvantage Technical constraint

15 Overall Comparison SG and GK 15 Variable SG GK Remarks 4) Thermal Energy Consumption slightly slightly Slight advantage for SG. lower higher 5) Electrical Energy Consumption higher lower Advantage for GK due to smaller process fans. 6) Product Quality slightly slightly GK provides better fired pellet temperature uniformity. lower higher 7) Fines Generation more Advantage to SG due to lack of transfer points. less fines fines 8) Organic Binder Use limited In general, advantage to SG, although some have reported advantage yes use to GK. 9) Capex slightly higher slightly lower Slight advantage for GK in process fan cost, no hearth layer return system and less building costs. 10) Opex similar similar Site specific. 11) Environmental Performance slightly higher slightly lower More potential to reduce NOx for the SG in a separate combustion chamber, otherwise no obvious advantage. Legend: Competitive advantage No advantage/disadvantage Disadvantage Technical constraint

16 Acknowledgements 16 The authors are pleased to acknowledge the following contributors for their valuable input: David Tucker Jose Murilo Mourão Miguel Sabanero Urano Medeiros Kelly Scott Mike Walsh

17 17 Thank You Ian Cameron Senior Director Iron & Steel Phone For more information, please visit