OTE Outotec Sintering Technologies Eng Web

Outotec® Sintering technologies40% of the world’s sintering Iron ore sintering has stood at the heart of the ferrous metallurgical processes for over half a century. Outotec has solid experience in agglomeration of fine-grained iron ores. We have built over 400 sintering plants with capacities ranging from 600 to 20,000 tons per day since 1920. Today, 40% of the world’s sinter is produced by our technology. Besides iron ores, it can also be applied for sintering of manganese ore fines. Over the years, we have developed a number of innovative technologies that increase the performance and reduce the capital and operating costs. Longterm research and testing with raw materials of different origins and process parameters, coupled with continuous development and improvements in mechanical design and process automation have made us an unparalleled technology partner. while incorporating noise attenuation equipment to meet local regulations. SOx and NOx emissions. located at the sinter machine’s discharge outlet. electrostatic precipitators and/or bag filters dedust the sinter waste gas and air from the plant dedusting system. the sinter is cooled. The product obtained from the process is a blast furnace feed of superior quality. These materials are mixed and granulated in one or more stages. protecting the grate bars of the pallets during the sintering process. For effective dust collection. Its surface is then ignited. Sintering produces a feed of extremely consistent quality in terms of its: n Chemical composition n Grain size distribution n Reducibility n Sinter strength Why sinter? Environmental safety Outotec sinter plants are designed to meet the most stringent environmental regulations. The cooled sinter is crushed to a pre-determined maximum particle size.. is screened out and recirculated to the sinter machine. We provide processes for limiting dioxin.002 Sintering technologies Tata Iron and Steel Co. air being induced through the ignited layer and sintering proceeding in the vertical direction in the sinter strand’s material bed. India. maintained by conveying the raw mix carefully onto the sinter machine. Undersized sinter that is not suitable for the blast furnace is recycled to the return fines bin. fluxes. has already three Outotec sintering plants in operation. solid fuel and return fines. Subsequently. . in-plant dust and spillage fines. Manganese ores can also be sintered before smelting in the electric arc furnace. usually 10–20 mm. Outotec® Sintering Process Outotec sintering process begins with the preparation of raw mix from iron ores. usually in a separate sinter cooler. A certain quantity. where it serves as a hearth layer. Water is added in order to assist the raw mix in obtaining optimum permeability for lower electricity consumption. Sintering is the agglomeration of fine-grained iron ores for blast furnace burden preparation. In integrated steel plants about 75% of the CO 2 emissions are generated in the blast furnace and about 12% in the sintering process. CO and pollutants like SO x . While CO is postcombusted. This reduces off-gas volumes by about 40–50% without affecting the sintering process. NO x . Therefore a part stream of the off-gas is recycled via the hood. and as there is only a minimum technical margin for CO 2 reduction measures in the blast furnace. Bleed in Recirculation gas system Fresh air supply system Typical flow sheet of a sinter plant with EOS® system. to reduce off-gas volumes by 40 to 50%. substantially saving on solid fuel. This means: n Lower capital investment n Reduced operating costs Conventional sintering uses ambient air to transport heat within the sinter bed. EOS ® brings significant benefits for all steel plant operators. When following the international CO 2 policy. However. EOS ® takes advantage of the fact that only a part of the oxygen in the air is consumed for coke combustion. the Kyoto protocol. resulting in smaller secondary gas treatment systems. EOS uses recycling technology ® Energy savings and reduced emissions What is more. dust and dioxins/furans are passed through the sinter layer together with the recirculated gas. and treating these in order to meet increasingly stringent environmental standards is expensive.Sintering technologies 003 Outotec EOS ® Emission optimized sintering for lower costs Iron ore sintering creates substantial off-gas volumes. That is why we have developed the emission optimized sintering process. enriched with ambient air to an oxygen content of 13–14% and used as intake process air. . requiring a high air flow rate. the pollutants are partially retained in the sinter layer and/ or thermically decomposed. each set containing one running roller and one pressure roller. both arranged on the same shaft Grate bars made from high alloyed cast steel Side walls of cast material Insulating sections to protect the pallet body . which have the advantage of minor investment costs and space requirements. providing a hearth layer of a predetermined height. in order to adjust the optimum moisture/ permeability of the feed mix. especially for fine grained ores.lowering power consumption n Optimum segregation of fine and coarse particles n Optimum formation of the material layer on the pallets The variable speed roll feeder is mounted on a separate support with rails and wheels to permit roll-in and rollout for maintenance purposes.004 Sintering technologies Proprietary equipment for control. Ignition furnace for optimum maintenance and operation Outotec ignition furnaces consist of standardized segments. Each pallet comprises n A cast pallet body. economy and safety High intensity mixing and nodulizing Mixing and granulation is performed in two separate high intensity mixers. Durability is also enhanced through the separation of each pallet from the chain by a lifting and lowering sprocket at each station. The required amount of process water will be added to the two mixers in predetermined ratios by means of spray nozzles. quality. as a single unit or in three pieces Exchangeable front plates Four roller sets. Both the feed bins for hearth layer and for feed mix are level controlled. Ultrasonic sensors control the bed height level of the individually motorized gates. each with straight refractory lined vertical side walls and a laterally-arranged special combustion chamber on each side. n n n n n Since our pallets only come into contact with one another on the horizontal section of the upper and lower track. the hearth layer bin is equipped with an adjustable gate. Its feeding station ensures a continuous supply of hearth layer and feed mix to the sinter machine. This design offers the optimum solution in terms of maintenance and operation: n Uniform ignition n Highly flexible operation in response to fluctuations in material bed permeability n Possibility of operation with a high rate of excess air n High safety standards Lurgi traveling grate Our solution for sinter machine is a Lurgi traveling grate consisting of an endless chain of pallets. Furthermore. This is an inclined plate across the pallet width. Its inclination and positioning in relation to the material flow from the roll feeder is adjustable for: n Improved feed mix permeability. wear is minimized. combined with an excellent mixing and granulation effect. Longer lasting pallets The roll feeder discharges the material onto a segregation plate. The feed mix hopper outlet is equipped with motorized gates for adjusting the amount of material to be discharged via a variable speed roll feeder. ”on-strand cooling” can be applied in particular appli-cations. the entire fraction is mixed. Height-adjustable wheels provide equalized.Sintering technologies 005 Discharge station for long service life The sinter strand discharges the sinter onto a crash deck. Coarse particles separated at the saddle front side are fed into the cold sinter double roll crusher. Natural segregation with the maintenance-free cascade classifier Outotec's new cascade classifier. individually supported on flat spring plates. A movable grizzly carrier is also featured. It functions based on: n Natural segregation by dropping or pouring material n Adjustable start-up saddles phase). cooling air fans are arranged outside the cooler.6 m. minimize cooling air leakages. While the cooler is driven by friction drive units via a segmented friction ring. separating coarse from fine size iron ore sinter stream material. replaces the scalping screen in front of double roll crushers. A concave material layer is built up on the sides of the chute. (adjusted once the during of guaranteeing removal inadmissible coarse material from the separated fines The cascade classifier is almost maintenance-free.4 to 1. from where it slides into a spiked roll crusher whose crushing arms grind it to a maximum size of 200 mm. minimizing the cooling air volume n Horizontal movement of the cooler trough. Our cooler features all of the essential attributes: n Annular arrangement of troughs n Cooling air pressed through the sinter n A bed height of 1. As the cooler moves. While passing through the opening. with the trough bottoms following a dip rail at the discharge station The cooler trough wheels run on a circular rail supported by a concrete sub-base. fine material in the middle and medium sized on top. since it runs on ”stone box type” saddles which do not touch the side walls. specially designed and equipped with wearresistant material. where the material is re-segregated. This mixed material falls onto a radially adjustable saddle. uniform wheel loads. Spillage collecting plates underneath each cooler trough bottom plate retain all sinter spillage and discharge it to the collecting hopper. large lumps from the rear settling on the bottom of the cooler. Special seal bars. the material accumulates on it to form a sloping material layer. the coarse material being deposited on the rear part of the lower chute section while the fine material is deposited in the center. while temperature optimized side wall clamping allows for thermo-expansions without stressing the cooler. Efficient sinter cooling While hot sinter is best cooled in a separate cooler. while fine material separated at the saddle far side by-passes the crusher and is mixed again with the crushed material underneath. a core flow develops. Direct charging to cooler improves cooling efficiency and reduces emissions The material discharged from the sinter machine enters a chute with a round opening. which also serves as a wind channel for cooling air. acting as a filtration layer . Energy savings together with reduced emissions: n Optimum permeability of the sinter layer on the cooler n n Optimal use of the cooling air Minimum spillage since sinter fines are held off the trough bottom n Minimum dust emission since sinter fines are covered by the middle size sinter fraction. Upon the withdrawal of the material. whose height is determined by the inner angle of repose of the sinter. . optimizing.006 Sintering technologies Sinter plant in Middlesbrough. plants can be operated with maximum energy savings and superior sinter quality. Flexibility brings extra benefits Our sinter plants are designed to cater for fluctuating production requirements.K. To enable high production rates. simulating and pre-tuning level 2 controllers (process management) based on a dynamic computer sinter model. These enable extensive supervisory control functions using ”standard” distributed or open control systems (DCS/OCS). some plants are designed for a specific output of up to 45 t/24 h/m². analyzing. State-of-the-art control systems Outotec sinter plant control systems include: n Return fines balance control n Material mixture computing and control with individual moisture control n Burn through-point control/sinter capacity control n Ignition furnace control with permeability measurement Such an architecture supports the addition of an operational layer above DCS/OCS for process management (level 3) including monitoring. U. For lower rates. 5 million tpy in single units n Availability 330–345 days/year n Specific production rates up to 45 t/24 h/m² Consumption figures (per ton of product sinter) n Solid and gaseous fuel: 1250–1400 MJ n Electrical energy: 28–32 KWh n Process water: 0. To improve the efficiency of existing plants we provide a number of alternatives. retrofits and capacity increases.05 m n 16–20 men per day Process parameters n Basicity CaO/SiO 2 : 1. Our full range of R&D facilities test sinter properties to meet international standards such as ISO. pot tests determine the key ore mix parameters (specific sinter output as a function of the applied suction and required sinter quality) for use together with the flux and solid fuel.15–6. ranging from individual equipment replacement to extensive plant rehabilitations.3 mm) 75–80% n RDI (-3 mm) 28–32% n FeO 5–8% Sinter plant modernization – a made-to-fit process Our solutions are not only valid for new plants but also revamps.Sintering technologies 007 Facts about Outotec sinter plants Traveling grate dimensions n 36–600 m² reaction area n 2–5 m machine width Capacity n 0. These parameters form the basis of sinter plant design.9 n Bed height: 500–730 mm n Suction: 130–190 mbar n Return fines rate: 18–25% Product qualities n ISO-strength (+ 6. ASTM. 3 R&D facilities providing economy and innovative technology Outotec’s long research pedigree. JIS and DIN.03–0. Operational manpower (4-shift basis): Plant modernization can include: n n n Replacement of obsolete equipment Upgrading of sinter plants Construction of plant units and new sinter plants with maximum leverage of the existing infrastructure . While test series yield specific data for the optimum technical and economical design of commercial plants. tailored to each customer’s specific needs. Germany. based on our own facilities in Frankfurt.2–2. forms the basis for the successful design and construction of sinter plants. Finland. industrial water treatment and the utilization of alternative energy sources. As the global leader in minerals and metals processing technology.com www. Outotec has developed over decades several breakthrough technologies. Outotec shares are listed on the NASDAQ OMX Helsinki. . The company also offers innovative solutions for the chemical industry. All rights reserved. ferrous@outotec. December 2011.com Copyright © 2011 Outotec Oyj.Outotec develops and provides technology solutions for the sustainable use of Earth’s natural resources.outotec.