China - Nanjing Steel Converter Gas Recovery Project (Vol. 3 of 4) : Supplemental environmental impact assessment for OG system 120T converter

ToR on OG System NISCO Supplemental EIA on OG System 120T Converter Gas Recovery Project Nanjing Iron & Steel Co., Ltd April 2005 1  ToR on OG System NISCO Table of Contents Chapter 1 General Description...........................................................3 Chapter 2 Main Pollution Source, Pollutant and Control Measures............11 Chapter 3 Introduction of the New 120t Converter.................................15 2  ToR on OG System NISCO Chapter 1 General Description 120 t converter will be installed in the Heavy Plate Mill which is affiliated to NISCO. See the following attachment for the details of NISCO. Location: It is located at DACHANG district, in the north of Nanjing City in a distance of 25 km from the central of the city (the straight-line distance is approximately 16 km). This plant faces the Yangtze River in the South and is close to Ningyang motor way in the north. In the eastern side it neighbors with Nanjing Thermal Power Plant, Nanjing Power Plant of North China Energy & Source Co. as well as Nanjing Chemical Industry Co. The region & location map of NISCO is shown hereinafter. Product, output and working staff: A new 120t top & bottom blown converter will be built with a liquid-steel output of 1,090,000t/a. The products include on-line sheared plate, plate sheared with dividing unit and hot rolled coil. The product specification and production distribution on each steel grade is shown in the following tables. 3  ToR on OG System NISCO 1. General Nanjing Iron & Steel Co.,Ltd. (hereinafter abb. as NISCO). is a province-level enterprise group established on the basis of Nanjing Iron & Steel Group Corp. Ltd. Through the development and construction for more than 40 years, it has become a large iron & steel complex with a comprehensive productivity of 2,000,000t pig iron, 3,500,000t liquid steel and 4,000,000t steel product. It is one of the key enterprise groups in Jiangsu province. In 2002, the sales revenue of NISCO is 14.5 billion Yuan, ranking No. 69 among the "Top 500" enterprises in China. Nanjing Steel is located at Jiangbei Industrial Development Area in Nanjing City along the Yangtze River. It enjoys favorable conditions in transportation. A special railway is provided in plant area which is connected with Beijing-Shanghai railway. An available 5000-ton plant-owned pier at Yangtze River can provide convenience for loading/unloading. In 2002, steel output of NISCO is 2,532,000t, the pig iron is 1,886,000t. The profit & tax realized is 750 mil Yuan, in which the profit is 410 mil Yuan. In the end of 2004, the original value of fixed assets is 3.75 billion Yuan and the net value is 2.01 Yuan. The main product is medium or small sized section steel and wire/rod, heavy plate, pack rolling sheet and steel strip, etc. All the steel products are of carbon steel and low-alloy structure steel except the heavy plate which are used as ship-building plate and boiler plate. The configuration of existing production system In coking, sintering and iron-making system there are two 42-battery coke ovens with productivity of 580,000 t/a; two 39m2 sintering machines and two 24m2 sintering machines with productivity of 2,500,000 t/a; two oxidized pellet shaft furnaces with the productivity of 800,000 t/a, one 300m3 blast furnace and four 350m3 blast furnaces with the productivity of 1,850,000 t/a. In steel-making plant there are three 20t BOF converters with the productivity 4  ToR on OG System NISCO of 1,700,000 t/a; one 70t ultra high power EAF and one ladle refining furnace with the productivity of 700,000 t/a; one R6m 4-strand billet caster, one R5.25m 5-strand billet caster, one R5.7-21m ultra lower-head single-strand slab caster, and R8m 5-strand billet caster with a total productivity of 1,700,000 t/a. In steel-rolling system there are one medium-sized blooming mill with productivity of 400,000 t/a, three small-sized section mill, wire / rod mill, heavy plate mill, steel sheet mill, strip mill per each with the rolling productivity of 2,600,000 t/a. in NISCO a complete quality assurance system has already been built up and successfully certified with IS09000 and ISO 2000 quality system. The products namely thread steel, medium plate and high wire rod were awarded with "Gold Cup Prize". In August 8, 2004, Nanjing Iron & Steel Complex Ltd. was established based on the joint-venture between NISCO and Shanghai Fuxing Group. It indicates that NISCO has been transformed from a pure state-owned enterprise to a non state-owned enterprise.. During the "tenth five-year plan" period, NISCO plans to invest twelve billion Yuan in technical updating for maximization and modernization. Now a "wide medium plate (coil) project" and its associated project has been implemented which will need investment of more than seven billions Yuan to readjust the product structure. This project has been approved by the State Council, and will be recorded as the one with the biggest investment so far in the history of NISCO and Nanjing area in the field of industry. After the commissioning of the project (in the third quarter of 2005 as per schedule), the productivity of plate (coil) per year will be up to 1,500,000 t. We also decide to build another plate production line recently by utilizing the fund through joint-venture combined with bank loan, in order to gain an additional steel output of 2,000,000t. The commissioning of this production line is expected to be finished at the beginning of 2006. Till then the total production capacity including the existing plant and the new production line will 5  ToR on OG System NISCO be up to 6,500,000 t. Through the capital-fund operation and involvement in the asset regroup with other steel mill at home and abroad, the productivity will be approximately 6,000,000 t~7,000,000t under the investment and share holding. By 2010, NISCO will reach the productivity of 15,000,000t in steel and fifty billions Yuan in sales revenue. 6  ToR on OG System NISCO figure 1: General layout of plate/coil project in NISCO 7  ToR on OG System NISCO Figure 2: Geography location map of the project 8  ) (% 38.0 20.0 12.0 4.5 5.0 1.5 8.0 1.0 00 10.0 1 t/a) 4 38.0 20.0 12.0 4.5 5.0 1.5 8.0 1.0 00 10.0 1 (10 Production 0 00 1800 180 000 00 00 80001 40002 80001 80001 80001 00- 00- 00- 00- 00- -18 x60 x60 x60 x60 x60 x60 x60 x6000 3520 3520 3520 (mm) 0- 520 00 00 3520 3520 3520 3520 00~ 00~ 00~ 00~ Size 0-3 x16 x16 30x160 x16 x16 x16 x16 6.0-50 3-50 NISCO 4.8-50x160 plate:6.4 plate:2.3~50 plate: plate:2.3-50 plate:2. plate:2.3-12 plate:2.3-50 Grade Plate: Coil, Coil, Coil, Coil, Coil, Coil, Coil, eeltS 9 on related 8T2 in society Based oni G3106 G3103 1002 G3115 G3106 G3101 APl5L ASTM ASTM ASTM Total Standards criterion ficat GB713 GB700 GB/T1591 EN GB6654 GB3273 JlS, YB(T)10 JIS, JIS, JIS, JIS, Plan DlN classi GB712 Production et EH32,, EH36, 50 A537 nVq 90 275 grade SM490 A573 A736 SS4 Pla picalyT 16Mn, SB4 SPV315 15M SM490 DH32 DH36 X42-80 15MnV 19Mn6 16MnR A515, 09SiVL steel A572, 20g, SM400, SB410, 16Mnq, SM400, StE690, Q195~Q SS400, AH32, AH36, SPV235, A202, and beam y plate g plate stemyS structural essel steel eam gn steel structural 1 Qualit plate OG lloya on on RoT bleaT Shipbuildin Pipeline Low- Boiler Pressure-v plate Bridge-b Engineeri machinery utomobileA plate Carb steel No 1 2 3 4 5 6 7 8 9  ToR on OG System NISCO Table 2: Product variety and specification No. Product variety Percentage Specification () Thickness: 4.8-50mm 1 Hot-rolled steel plate 75 Width: 1600~3520mm Length: 6000-24000mm Thickness: 2.3-20mm Width: 1600~2800mm 2 Hot-rolled steel coil 25 Unit weight of coil: 20.5kgmm Coil weight: ~45t(max) 10  ToR on OG System NISCO Chapter 2 Main pollution source, pollutant and control measures 2.1 Main pollution source and main pollutant Primary fume containing dust and CO is generated during converter melting process SS contained waste water is produced during wet-gas cleaning process of converter Sludge collected from waste water coming from converter-gas scrubbing system Noise produced by pump, motor, etc. during operation. 2.2 Pollution control measures and results 2.2.1 Fume-emission control Passing through furnace mouth and fume hood, the primary fume generated in converter smelting will enter into evaporated cooling duct. After cooled and cleaned by two-stage Venturi tube as well as de-watered by dehydrator, it will be discharged via 47m stack. The dust content is lower than 120mg/Nm3, which is in compliance with the criteria of category 3 (criteria of emission:150 mg/Nm3) specified in Criteria for Air Pollutant Emitted from Industrial Furnace/Kiln . During emission, in case that CO content in fume is high, the ignition device on top of stack will be ignited automatically to make CO in fume into CO2 through combustion. 2.2.2 Treatment of waste water The total water consumption is 629m3/h and the make up water is 80m3/h.The reusing rate of water is 80%. The method of "using indirect cooling water to make up direct cooling water" and series arrangement will be adopted in production process. 11  ToR on OG System NISCO The indirect cooling water is mainly used for 2-stage Venturi tube jacket and fan, with only a water temperature rise and no contamination. The water will be recirculated and cooled through cooling tower and reused in direct cooling system and other system. A little amount of ~32 m3/h non-pressure waste water will be discharged. The discharged waste water is in accordance with criteria of category 1 (SS content=70 mg/L) specified in Criteria for Waste Water Discharge in Steel Industry. The direct cooling water system mainly contains the water from gas scrubbing system. The waste water will be reused after thickened in vertical sediment basin, cooled in cooling tower and pressurization, and has no water to be discharged. The slurry discharged from the bottom of sediment basin will under through dehydration treatment in board-frame filer press. 12  ToR on OG System NISCO 2.2.3 Solid waste treatment and overall utilization The slurry produced from wet purification system of converter fume is pressed into slurry cake with the board-frame filter press. The main composition is ferro- oxide which will be used for material proportion in sintering plant. 2.2.4 Noise control The fan is installed in an separate room for sound proof. Flexible connection will be adopted at the inlet and outlet of fan and in between the pipes. Hydraulic pump will be installed in a separate room sound isolation. After adopted the above-mentioned measure of sound insulation, noise reduction and distance attenuation, the noise level at the plant boundary can be maintained as before. The main pollution source and main pollutant for this project are shown in table 3. Table 3 Main Pollution Source and Main Pollutant No. Pollutant Control measure Emission/discharge/level Emitted through high stack afterEmission intensity: 120 mg/Nm3 1 Dust-laden fume dedusting by 2-stage Venturiemission amount:23.1t/a tube Non-pressure net waste water 2 Waste water SS<70mgL discharged outside :32m3/h, 208,000 m3/a. 2 Slurry cake Used for proportioning in sintering plant 3 Noise of fan Sound proof inside workshop and distance attenuation. 4 Noise ofSound proof inside workshop hydraulic pump and distance attenuation. 13  ToR on OG System NISCO 2.3 Environment monitoring & the management organization of environmental protection The environmental management department will take the responsibility for the work of environment control and monitoring in this project. 1 3x20t existing converter steel-making process flow chart and sewage production points 14  ToR on OG System NISCO Scrap Hot Metal Bulk Material, Ferroalloy Exhaust stack Secondary Bag Waste Refractory 3X20t Converter fume Filter Filtered dust Primary fume Liquid steel Slag (Burnt to emission) Return to sinter for Exhaust stack burdening fume BOF-gas fume W OG System aste fan house wateraftertreatm water W aste Treating in vertical Slurry settling tank W ent aste Thickener water De-watered mud cake Cooling tower OG slurry de-water then to sinter plant for burdening OG system includes(Treatment in vertical settling tank) Converter fume from evaporation cooling ductStage-1 overflow VenturiStage-1 impact-type gravity dewatererStage-2 Venturi with annular gap adjustable throatStage-2 900 elbow dewaterer cyclone dewaterer Fig 1 Process flow chart of 30t BOF and pollutant source 15  ToR on OG System NISCO Table-4 Pollutant Generated by 3*20t BOF without Gas Recovery System and Emission Criteria Pollutant Pollutant Emission Dust content at emission Emission criteria rate Fume dust 150mg/Nm3 100mg/Nm3 18.1kg/h SO2 2000 mg/Nm3 Very small amount Primary BOF Content in off gas CO290%. off gas (totally BOF gas totally burnt and bleed bleeding) CO2 out without recovery. Most of CO in gas will be burnt out to CO2. Small amount of CO will be contained in the gas in case of not fully combusted. Fume dust 150mg/Nm3 The treatment will be completed in May,2005 Secondary SO2 2000mg/Nm3 Fume dust emitted to outside < 50 BOF off gas mg/Nm3 CO2 311423t/a scrap will be selected through slag tightly covering under high slag temperature, crushing and magnetic screening. After that slag Solid waste block will be used for road paving and pit filling. Fine slag can be recycled BOF dust & 47629t/a return to sintering plant and used slurry for burdening (2) pollution control measure 16  ToR on OG System NISCO Chapter 3 Introduction of the new 120t converter (1) Process flow chart and pollution-generation sector Scrap Hot Metal Bulk Material, Ferroalloy Exhaust stack Bag Waste Refractory Secondary 120t Converter fume Filter Filtered dust Primary Liquid steel Slag fume (gas) Return to Exhaust stack sinter for burdening gas OG BOF-gas gas Gas W fan house W asterwatertreatment astewater gas slurry E-precipitator dust Thickenin g in gas W astewater thickener To wire-rod Mill shop, etc. burdening sinterfor Return to De-watered mud cake Cooling tower OG slurry de-water then to sinter plant for burdening OG system include: Stage-1 overflow Venturistage-1 impact-type gravity dewatererstage-2 Venturi with annular gap adjustable throatstage-2 900 elbow dewaterercylone dewaterer Fig 2 Process Flow Chart of 120t BOF and Pollutant Source 17  ToR on OG System NISCO Table-1 Pollutant Generated by 120t BOF without Gas Recovery System and Emission Criteria Pollutant Pollutant Emission Dust content at emission Emission criteria rate Fume dust 150mg/Nm3 100mg/Nm3 18.1kg/h SO2 2000 mg/Nm3 Very small amount Primary BOF Content in off gasCO2CO off gas (totally 90%.BOF gas totally burnt and bleeding) CO2 bleed out without recovery. Most of CO in gas will be burnt out to CO2. Small amount of CO will be contained in the gas in case of not fully combusted. Fume dust 150mg/Nm3 11.5mg/Nm3 11.1 kg/h Secondary SO2 2000mg/Nm3 Very small amount BOF off gas CO2 small amount 160000t/a scrap will be selected through slag tightly covering under high slag temperature, crushing and magnetic screening. After that slag Solid waste block will be used for road paving and pit filling. Fine slag can be recycled BOF dust & 16225t/a return to sintering plant and used slurry for burdening 18  rate kg/h 7.2kg/h 0.2kg/h .111 Emission 2 be ll wi ack.st CO willit slag be e ing Fin unit) it gh to can gas, y burden crushing bloc gas, throu combustion through filling. for 3 BOF recover mN yr ed 3 changed emission ble mN in ace ure, slag pit amount % amount pickup d 5t/a plant gas at prima be 90 furn amount an h hit 100mg/ in and small usted. small 1622 < will <10mg/ scrap temperat (w CO small ter screening, vingap sintering Content 35% nitorig ryeV CO 2 throug exha 3 ryeV af ghih d recycled. etic to combustion. out at roa be d CO nt and NISCO CO with of h mN/g 00t/a; magn for can in bur m5. returne F while burnt Most throug while be system 11 1600 covering and used slag BO ng in 120t NISCO for eria reheati criteria crit to 3 3 3 3 3 Criteria mN mN 3 mN ed mN emission mN mN 19 mg/ suppli 3 mN mg/ 150mg/ 2000 300mg/ shop, mg/ 2000 150mg/ 2000mg/ Discharge mainly mill 300 and Emission/discharge gas in ant BOF furnace furnace: Pollut of ant dust 2 2 dust 2 2 dust 2 2 SO CO SO CO SO CO slag slurry Pollut Fume Fume Fume Amount BOF ator 2 ngir nda the cleaned bleaT red: to ente fume E-precipit holder Emitted further waste Recove with before gas supplied customer stemyS Description secondary Solid OG fume BOF on RoT Primary BOF  ToR on OG System NISCO (2) Pollution control measures Waste-gas pollution control measures As shown in Fig. 2, the pollution source in converter melting process is mainly the primary and secondary fume. During production a lot of primary fume is generated, which contains a high proportion of CO, and is a kind of good secondary energy source. In the meanwhile, this off-gas contains a lot of dust. So it cannot be used directory without any treatment. Direct emission of the off-gas will bring serious pollution to the atmosphere. The secondary fume is mainly generated during the procedures of hot-metal charging, tapping and slag disposal. BOF gas primary fume control measures (OG system): Converter gas from evaporated cooling fluestep-1 overflow Venturi tubestep-1 impingement-type gravity dehydrator step-2 circular-seam throat-opening adjustable Venturi tubetwo-step 90