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NOTE ON INSTALLATON OF 3 X 315 TPH BOILERS INPLACE OF 3 X 160 TPH BOILERS for AMENDMENT/CORRIGENDUM IN ENVIRONMENTAL CLEARANCE AT GREENFIELD ALUMINA REFINERY WITH SMELTER AND CO-GENERATION POWER PLANT BY ANRAK ALUMINIUM LTD. At APIIC INDUSTRIAL PARK, MAKAVARAPALEM MANDAL, VISAKHAPATNAM DISTRICT, ANDHRA PRADESH Prepared By B.S. ENVI-TECH (P) LTD Hyderabad – 500 057 BRIEF NOTE FOR AMENDMENT/CORRIGENDUM IN ENVIRONMENTAL CLEARANCE BACKGROUND M/s. Anrak Aluminium Limited is implementing a 1.5 Million Tonnes Per Annum capacity Alumina Refinery at Makavaripalem village ,Visakhapatnam District, Andhra Pradesh. Three boilers of (3x160 tph) Boilers were proposed to meet the steam requirement of the process as per the basic engineering which would also co-generate 90 MW of power as a bi-product on a double extraction mode. The project was accorded Environmental Clearance by the Ministry vide letter no F. no. J-11011/813/2007-1A II(I) dated 16th October, 2008. The project is nearing completion and is likely to be commissioned by January, 2013. The steam requirement for the process was initially proposed from 3 boilers of 210 tph capacity. However, during detailing of the Project based on the requirement of steam for the process, it was felt the normal Steam Consumption would be about of (2.3) t/t alumina and this together with the Internal steam consumption of the Co-Gen plant (~10%), boilers of 315 tph need to be installed. (Even in the Pre / Feasibility study report the Boiler Steam capacity has been mentioned as 3 X 270 tph and also during the presentation to the Special Committee of Ministry, on the Environmental aspects, 3 nos . of (295) tph was mentioned). Considering the above and the standard ratings of the Boiler available from the Boiler Manufacturer (M/s Thyssen Krupp, Pune), Anrak has installed 3 boilers of 315tph (2 nos operating + 1 no standby) to meet the steam requirement. The CFBC boiler installed will be highly efficient ( Boiler Efficiency - upto 90% against the 80% for Boiler considered in the EIA / EMP) and in order to save energy (under the worst case scenario), the design of the system allows full condensation of steam, thereby allowing increased power generation, during outings / curtail in production capacity of the Alumina Refinery due to any problems. The two 315 tph boilers can generate 90 MW when the refinery is in full operation and upto 150 MW when the refinery is not in operation. Considering the fact that adequate requirement of steam is essential at all times (including the yearly statutory outings for Boiler Inspection), a stand by Boiler of the same capacity is essential to assure the full capacity utilization of the process and hence a stand by boiler is required and hence has been proposed. With the efficient and advanced energy conservation and condensate polishing system adopted in the Refinery, atleast 90% of the Steam supplied would be returned back as “Good Quality” hot condensate to the Co-Gen Plant thus improving the energy efficieny and also reducing the fresh water requirement for the Boilers, in spite of their higher rated capacity. In addition by adopting the “Red Mud Pressure Filtration Technology” for the first time in the Country, the water requirement for the Alumina Process has been reduced, thus enabling to operate the Co- Gen Plant without any additional water requirement. Coal / Pet coke was envisaged in our EIA report and the same has been approved. Now also we propose to use the Pet Coke / Coal as fuel without any change in the Raw Material. Coal Consumption given in the EIA / EMP report for cogeneration plant is 1542 t/day (steam for 90 MW power generation followed by process utilization). With the increased steam capacity the fuel consumption would be 1168 t/day because of the improved Boiler Efficiency and also the fact that the Project has planned now to use 70% pet coke and 30 % imported coal (high calorific value Indonesian coal). In order to keep the Sulphur-di-oxide emission within the permitted value (as per EC accorded), AAL is installing a Lime injection arrangement into boiler (crushers ready for installation – shown below, so that the Sulphur-di- oxide can be maintained within the permitted value (as per EC accorded). Thus by bringing in advanced technology, improved efficiency & advanced conservation measures, Anrak is confident to maintain the water consumption & emissions, well within the already declared levels . The change in environmental parameters due to installation of 3 X 315 TPH boilers along with comparison of emissions for which EC was granted is given below Air emissions AAL was granted Environmental clearance for utlisation of 3 X 160 TPH boiler and power production of 3 X 30 MW using Indian coal having calorific value of 3500 kcal/kg, sulphur content of 0.6% and ash content of 40 %. Due to the reasons elaborated earlier, it is proposed to install 3 X 315 TPH steam generators (2 nos operating + 1 no standby) which will be operated on blend fuel comprising of 70 % Petcoke and 30 % imported coal having the following fuel characteristics TYPICAL ANALYSIS OF FUEL (% BY WEIGHT) S.No. Description Imported Coal Pet Coke 1 Carbon 60.59 87.0 2 Hydrogen 4.29 2.72 3 Oxygen 7.30 1.26 4 Sulphur 0.59 5.90 5 Nitrogen 1.18 0.63 6 Moisture 13.67 0.11 7 Ash 12.38 2.29 8 GCV (kcal/kg) 6000 8000 Comparison of the emissions for which EC was granted and now proposed is given the following table FUEL CONSUMPTION AND EMISSION DETAILS EC Amendment/Corrigendum of Accorded EC requested Fuel Indian Blend Fuel Coal (70 % Pet Coke + 30 % Imported Coal) Carbon % 36.20 79.08 Hydrogen % 1.70 3.19 Oxygen % 6.00 3.07 Sulphur % 0.50 4.31 Nitrogen % 0.60 0.80 Moisture % 10.00 4.18 Ash % 40.00 5.32 GCV (kcal/kg) 3500 7400.00 Fuel Consumption, t/day 1542 1168 - 743 t/day (pet coke)+424 t/day (imported coal Stack Height, m 105 105 Stack Dia, m 3 3.0 Flue gas temperature, oC 150 150 Flue gas Velocity, m/sec 25 24 Particulate Matter, 5.99 5.88 gm/sec Sulphur Dioxide, gm/sec 214 11.65 (with capture efficiency of 90%) Oxides of Nitrogen, 44.9 44.1 gm/sec The stack height requirement as per CPCB norm for 2 X 315 TPH boilers at Sulphurdioxide capturing efficiency of 90% is 42.9 m. AAL has already installed a tall stack of 105 m comprising of 3 flues. Control of Sulphur Dioxide Emissions To reduce the SO2 emissions, it is proposed to inject Limestone along with the fuel in the Boiler. Injection of limestone will result in capturing of upto 90 % of the SO2 generated. Hence the emission into the atmosphere will be only 10 % of the SO2 generated. The details of SO2 emissions and reduction with limestone injection vis-à-vis the emissions for which EC was granted are shown below : EC Amendment/Corrigendum of EC Accorded requested Without lime With lime injection injection Sulphur Dioxide, 214 1165 11.65 gm/sec It may be noted from the above table that the emission of SO2 will be 11.65 gm/sec against the permitted value of 214 gm/sec (as per EC). Water consumption AAL through project feasibility studies has ensured that there will not be any increase in consumption of water for cooling and steam generation. This is because of return of recovery of 90 % of the steam as “Good Quality” condensate to the Co-Gen Plant and increase of Cycles Of Concentration of condensate cooling water. The water requirement of the plant will remain same as per the permitted water balance based on which EC was accorded. This is reproduced below WATER BALANCE, m3/day EC Accorded Amendment/Corrigendum of EC requested Require Loss Waste Requir Loss Waste ment water ement water 1 Refinery Process 22700 17100 5600 22700 17100 5600 2 Refiner 18000 14500 3500 6000 5400 600 y Cooling 3 Smelter 1800 1340 460 4 Cogene 10200 7760 2440 ration 5 Boiler makeup 360 180 180 360 180 180 6 DM plant 50 0 50 50 0 50 7 AC ventilation 240 240 0 240 240 0 8 Domestic 125 25 100 125 25 100 consumption Total 41475 32045 9430 41475 32045 9430 SOLID WASTE GENERATION The solid waste generation from operation of 2 X 315 tph boilers (70 % Pet coke + 30 Imported coal and comparison of solid waste quantity for which EC was granted is given the following table FUEL CONSUMPTION AND EMISSION DETAILS EC Amendment/Corrigendum of EC Accorded requested Fuel Indian Blend Fuel Coal (70 % Pet Coke + 30 % Imported Coal) Ash % 40 5.32 Fuel Consumption, t/day 1542 1168 Ash Generation, 617 t/day 62.1 It may be noted from the above table that the solid waste/ash reduction will be to the tune of 90% when compared to the permitted generation (as per EC) PETCOKE/COAL TRANSPORTATION The Petcoke is available in plenty at Visakhapatnam which is 65 km away from the project site. About 60 trucks will be hauling this load in a day. Alternatively Petcoke and Coal also will be imported to reach Visakhapatnam / Gangavaram Port at about 30 km from the project site. The Coal and the petcoke movement is given below. The number of trucks transporting the Fuel will be reduced from 77 to 58 per day with the proposed fuel combination, thus reducing the auto emissions. The entire road route from Visakhapatnam / Gangavaram to Plant Site would be through NH 5 ( 46 kms ) & State Highway (18 kms), thus avoiding any small roads & villages.