Sponge Iron Industry


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Pollution in the Coal Based Sponge Iron Industry in India

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Sponge Iron Industry

  1. 1. Pollution in Coal Based DRI Summer Internship Project, 2012 Supervised by Susmita Dasgupta, ERU, JPC 1
  2. 2. DRI, or directly reduced iron is amethod of producing solid iron from iron oxide 2
  3. 3. Prepared by Nilopher Khan and Garima Sharma, Teri UniversitySupervised by Dr Susmita DasguptaPRESENTED TO ECONOMICRESEARCH UNIT, JOINT PLANTCOMMITTEE, JULY 2012 3
  4. 4. Iron from iron ore can be• In solid form • Or in molten formIn solid form, iron ore can In molten form iron can be be produced in the1. DRI produced in coal 1. Blast Furnace, needs based kilns coking coal.2. HBI produced in gas 2. Corex , can use based kiln. significant quantities of3. DRI does not need non coking coal but coking coal at all. cannot do away with it totally. 4
  5. 5. DRI is preferred in India because of1.Small scale of production.2.Access to iron ore.3.Paucity of coking coal in India. Between 2004-05 and 2009-10, the DRI production in India has increased by 24% as compared to only 8% for steel per annum. For steel produced through the coking coal route, the production growth is only 5.5%.• Source: JPC ,2011. 5
  6. 6. In India, 27% of all steel is produced through coal DRI And 7% of all steel is produced through Gas DRI And 20% is through the scrap route. Source: JPC,2012 6
  7. 7. This means that the DRI segment is a vital constituency of the steelindustry.54% OF INDIAN STEEL IS THROUGH THENON BLAST FURNACE ROUTE.SOURCE: JPC, 2012. 7
  8. 8. India is the world’s largest producer of DRI India produced 28 million tonnes of DRI in 2010 as against 57 million tonnes of global production. Source: World Steel Association, 2012. 8
  9. 9. DRI is produced and consumedlocally; being unstable in composition, DRI cannot be exported out or transported over long distances. Factories are located close to raw material sources 9
  10. 10. No wonder then most DRI plants are located in Odisha, Jharkhand, Chhattisgarh, West Bengal and KarnatakaSince they are rich in iron ore and coal.Source: CSE, 2012. 10
  11. 11. Raw DRI Process materials, partly coal, iron ore, After Burn Flue gas Chamber fluxes enter the rotary kiln The remainder Rotary kiln coal in = 2.5% Slo and 0.47 rp pe powdered form m sp e e d and hot air is charged Preheating Solid iron and zone or unburnt char,combustion zone lime is where coal is heated discharged Cooler discharge and product separator 11
  12. 12. 12
  13. 13. Paths of Iron and GasDRI Route Reactant Gas route1. Raw material yard 1. Rotary kiln discharge or2. Crusher, screener combustion end.3. Rotary kiln 2. Gas Conditioning tower4. Recuperator 3. After Burn Chamber5. Cooler discharge 4. Gas cleaning plant6. Product separator 5. Dust settling chamber7. Stock house 6. Waste Heat Recovery8. Loading points Boiler9. Trucks 7. Stack 13
  14. 14. Input Output In DRI Plants per tonne of DRIMatter Input OutputSolids Iron Ore 6-20 mm : 1500 kg Sponge Iron +3 mm: 790 kg Coal 0-3 mm : 300 kg Sponge Iron 1-3 mm: 210 kgs Coal 3-15 mm: 700 kg Sponge Iron -1 mm: 50 kg Limestone: 0-3 mm: 75 kg Char +3mm :30 kg Char 1-3mm: 75 kg Char -1mm:195 kgAir 6000 Nm3 5000 Nm3Energy in Gcal Coal = 6 Char = 1.15= 10 (9) Cooling 0.3 Sponge Iron =1.7 Waste Heat Recovered = 2.25 Unaccounted radioactive = 0.5Source: http://www.newagepublishers.com/samplechapter/001741.pdf 14
  15. 15. Unfortunately,DRI is a polluting industry Air, water, solid wastes containing mainly PM, SO2, NOX and CO abound the ambient environment. Source: CPCB,2008 15
  16. 16. Garbage Factor for a tonne of sponge iron unit.INPUT (in Tonnes) OUTPUT (in Tonnes)1.6-1.75 Iron Ore 1.8-2 Carbon Dioxide1.2-1.5 Coal 0.25 Dust0.035-0. 5 Dolomite 0.29 Coal Char1.5-2 Water 0.02 Kiln accretions 0.2 Sulfur Dioxide with water vapour Water vapourSource: Down to Earth, September 16,2006. 16
  17. 17. Sources of Air PollutionProcess Fugitive1. Combustion of coal in the 1. Raw material handling and preheating zone, kiln2. Oxidation of iron ore in the feeding area. process zone, kiln 2. Recuperator (in lieu of3. Flue gas from the kiln WHRB) through the upper end.4. Dust of char, unburnt lime, 3. Discharge end and cooler sulphur, alumina and others discharge. through the discharge end. 4. Product separator.5. Flue gas through the cap of the After Burn Chamber. 5. Work area of plant.6. Particulate matter from ESP 17
  18. 18. Dust Collection Centers Source: CSE 2008Location NomenclatureRaw material storage yard Stock houseCoal is crushed for charging as powder Coal CrusherIron ore is crushed to fit 5 to 16 mm size Iron crusherRaw materials sent to plants Transfer pointsSponge iron is cooled by spraying water Cooler dischargeSponge iron rests before screening and separation Intermediate binSponge iron is separated from char Product separationProduct is stocked Product house 18
  19. 19. Norms of Air Pollution Source: CPCB, 2010.Process Fugitive• 100 mg/Nm3 for CPCB. • 2 mg/Nm3• Lower at 86 mg/Nm3 for Karnataka, 69mg/Nm3 for Chhattisgarh. 19
  20. 20. Sources of water consumption and pollutionWater consumption Water pollution1. Rotary kiln cooler. 1. Cooler discharge contains2. Cooler discharge. solid waste particle. 2. Gas coolers also contain solid3. Gas Cooling particles. Water is circulating water 3. Some sulphides are mixed in the sense the water irretrievably into water. which is used to cool the 4. Water is sprayed on dust kilns is again used to cool while disposing it off in the coolers of solid trucks. discharge and flue gas. 5. Water in gas scrubbing may Make up water is kept in contain PAH compounds. reserve. 20
  21. 21. Water Requirement in m3/tonne DRIPurpose Water in m3/tonne DRI Nature of waterCooling 1.32 Circulating and non contactABC 0.48 Direct and contactDust suppression 0.30 Direct and contactWet Scrubber 0.78 Direct and contactTotal Contact 1.54 To be recycledTotal Circulating 1.32 To be made upTotal Water 2.88Source: CSE, 2008 21
  22. 22. 707 kgs/ tonne of DRI is solid waste. Source: CSE,2012 22
  23. 23. Solid wastefrom DRI is wet dust in the form of sludge And is mostlyallowed to drain out into rivers, ponds, fields. 23
  24. 24. Solid waste in DRI Plants Source CSE, June 2012Dust Due to Source Percentage of Total DustChar Dust Incomplete combustion. Rotary kiln, Recuperator 42% Gangue and stony elements.ESP Dust Ash in coal, incomplete waste Stack connected to ESP 24% recovery and gas cleaning.Dust Settling Impurities in raw materials, Stack connected to Gas Cleaning 3%Chamber incomplete combustion of Plant, sometimes the Waste coal, poor oxidation of ore. Heat Recovery Boiler.Cooler Discharge Due to physical fall of Ambient spillage, bag filter 15%and Product materialSeparating areaABC Dust Poor waste heat recovery ABC Cap 5%Kiln accretions Poor quality coal, non Stack connected to kiln 11% preheated material, over oxidation of iron ore due to presence of sulphur. 24
  25. 25. Standard Norms for discharged effluents. Source: CPCB, 2008.PARAMETER PERMISSIBLE LIMITpH 6.5 ~ 8.5COD (mg/L) 250BOD (mg/L) 30O & G (mg/L) 10Flouride (mg/L) 5Hexavalent Chromium 0.1(mg/L)Iron (mg/L) 3Total Chromium (mg/L) 2Manganese 2(mg/L)TSS (mg/L) 100Cyanide (mg/L) 0.2Phenolic Compounds (mg/L) 1Sulphide (mg/L) 2 25
  26. 26. Pollution from the sponge iron industries is the core reason whycommunities rise in arms against this industry. 26
  27. 27. Various CSE Reports of 2008 inform us1. In Odisha, women from the Bonai Vana Suraksha Committee marched up to the District Collector with samples of soil, water and grain to protest against sponge iron plants.2. Similar protests in Keonjhar and Sundargarh.3. In Chhattisgarh, popular protests led to closure of offending units and discovery of illegal operators.4. Public protests in Chhatisgarh were around a sudden increase in respiratory diseases and skin allergies.5. In Andhra Pradesh people filed cases in courts and obtained compensation for lost kharif crops.6. In Karnataka, there is an ongoing protest in Bellary against sponge iron industries. 27
  28. 28. Blast Furnace vs. DRI Source: CSE,2012.BF must be taken together withCoke Ovens and Sinter Plants Coal based DRI• Raw material consumption • Raw material consumption in tonnes per tonne of iron in tonnes per tonne of iron = 3.5 = 5.08• Thermal Energy Consumption = 0.4 ( C0) • Thermal Energy +0.5 (Sinter/Pellet) + 4.5 Consumption = 7.5Gcal/ (BF) = 5.4 Gcal/ tonne of tonne iron • Pollution Norms = 100• Pollution Norms = 50 ( CO) + 100 (Sinter/Pellet) + 150 mg/Nm3 (BF) = 300 mg/Nm3 28
  29. 29. Blast furnaces have higher stack heights due to larger volume DRI have lower stack due to smaller volumes and hence pollution impact is higher. 29
  30. 30. Interestingly, Coal DRI is one third as much polluting asthe Blast FurnaceRaising the stack height might actually help. 30
  32. 32. Features of sample1. Nearly 95% of sponge iron units in West Bengal have been considered.2. All plants are declared as red hot.3. Plants occur in clusters like Durgapur, Jamuria and others in Burdwan; in Bankura, Purulia, Haldia in East Midnapore and in West Midnapore.4. All plants had run for 720 hours from the last measurement.5. All plants are coal based DRI, using SL/RN Process.6. Sampling was done for 25 to 30 minutes. 32
  33. 33. Data reveals1. Size is not related to flouting of norms. Lower stack heights are not related to pollution.2. Commonest source of pollution is the kiln area due to combustion and carbonization faults. This is due to poor quality of raw materials.3. Due to poor combustion, thermal efficiency is low and heat exchange is also low.4. The existence of pollution control equipment does not guarantee clean operations. Poor raw material quality may not permit the proper running of facilities.5. Sulphides lead to higher temperature of flue gas.6. High CO2 interferes in nitrogen cycle leading to high Nox in emissions.7. Sludge is not controlled because of poor commercial reuse value.8. Char is generated due to low quality of coal. 33
  34. 34. CSE Study, West Bengal Sponge Iron Industry Clusters November 20111. WBPCB fails to control pollution. Irregular monitoring. No enforcement.2. Factories are repeat and habitual offenders.3. 92% of inspection reports show abnormally high emissions from the kilns.4. 52% fail to meet emission standards.5. Solid waste management is pathetic.6. Open storage of raw materials a major issue.7. Sponge Iron units do not use the pollution control equipment.Source: WBPCB,2011. 34
  35. 35. West Midnapore, CSE Report• People’s movement very strong against the sponge iron industry especially Rashmi Cement/ Ispat in 2009, in West Midnapore.• Maoist politics emerged solely due to pollution from sponge iron plants in West Midnapore.• Pollution Control Board found gross violation on water, air and solid waste disposal.• Nagarik Mancha led campaign against Rashmi Ispat. 35
  36. 36. Jamuria, Burdwan• Poor water quality.• Cattle has stopped grazing.• Fish inedible.• Units release pollutants at night from the ABC cap to avoid inspection.• Due to water shortage in Jamuria, water is not used as dust suppressant. 36
  37. 37. West Bengal Pollution Control Board• Romita Dutta in Live mint reports that WBPCB has issued closure notice to 50-60 units out of the 250 units in West Bengal.• More than 40% of the units in West Bengal violate the environment.• WBPCB claims that night inspection in West Midnapore was stalled because of Maoists.• According to WBPCB, air pollution has been the main problem. 37
  38. 38. CSE Recommendations• Kilns with capacity less than 300 tpd should be phased out.• Only integrated plants should be allowed in the future.• Mandatory standards for material handling, storage and transportation must be enacted.• New cluster based standards should be imposed.• Stricter enforcement. 38
  39. 39. Pollution Control Mechanisms (CSE & CPCB Recommendations)1. Concrete floor in the work area as well as in the material handling area.2. Use of covered trucks and enclosed hoppers to transport dust and ash.3. To put a WHRB after the ABC so that the GCC is avoided.4. Use of ESP instead of the DSC attached to ABC and GCC.5. Use of magnetic separator at the discharge end.6. Use of suction hood, bag filter and ESP to cooler discharge.7. Use of raw material i.e. coal preheating to reduce energy consumption and char.8. Use of pellets. 39
  40. 40. Our recommendations for waste Utilization in DRI• Char is used as fuel in thermal power plants, industries and domestic purposes. Coal fines can be mixed with char fines for fuel.• Dust and fly ash can be made into bricks.• Kiln accretions and slag can be used as landfills and road making.• Product circuit dust can be used as activated carbon in edible oil refineries.• Dolchar and char can be used in cement making.• Waste Heat is recovered in captive power plants.• Waste water recycled as make-up water. 40
  41. 41. Our Recommendations ( Technical)1. We can set up air quality monitoring stations to track certain specified air pollutants and toxins. Delhi for example has set up several real time air quality monitoring stations. The system uses Lidar (light detection and ranging) technology, which releases and captures a laser beam and measures the before- after difference to gauge the concentrations of various pollutants in the air.2. Construction of screen grit chambers to trap the sludge from the effluent through the introduction of de-salting tables to minimize the quantity of salt in the effluent.3. Use of Sonic Horns, a pneumatically actuated device which produces high pressure acoustic energy or sound waves that are capable of fluidizing powder that adheres to surfaces in the bag filter. This low frequency vibration provides an effective means of cleaning the filter. The FES sonic horn helps in the removal of powder from walls, ceilings, curtain, and filter bags in the dust collector. ( http://www.fesintl.com/htmfil.fld/sonichrn.htm )4. Use of Heat pipe Exchangers instead of WHRB, which can transfer up to 100 times more thermal energy than copper, the best known conductor. Heat pipe is a thermal energy absorbing and transferring system and have no moving parts and hence require minimum maintenance. 41
  42. 42. New GadgetsHeat Pipe Exchanger (HPHE) Sonic Horn 42
  43. 43. Our Recommendations (Legal)• reduction of green house gas by implementation of clean development mechanism (listed by UNDP/GEF) is found to be depend upon the sincerity and integrity of the plant owner.• Granting land on lease basis with ultimate owner as the community.• Granting license on term basis to the plant owners. 43
  44. 44. Our recommendations (Institutional)1. Sponge iron industries may come under a cooperative organization for management of waste.2. Assured quality of raw materials must be provided. Raw material quality must be declared.3. Pooled resources to set up common facilities towards pelletization, or ore beneficiation, transportation and others.4. Electronic alarms in the Air monitoring systems (that use LIDAR technology) might be set up on facilities connected to a central computer which shuts operations whenever limits of emission are crossed. This has been CPCB’s recommendation for a long time. 44
  45. 45. THANK YOU 45