IV.ENDÜSTRİYEL FIRINLAR VE REFRAKTER SEMPOZYUMUENDÜSTRİYEL FIRINLARDA MODERN SOĞUTMA

TEKNİKLERİ İLE ATIK ISI GERİ KAZANIMI ve ENERJİ ÜRETİMİ

Ertan Öcalan*, Mathias Harde***Oschatz GmbH & Reining Heisskühlung GmbH Bölge Sorumlusu, Istanbul

Oecalan.e@oschatz.com**Reining Heisskühlung Genel Müdür Mülheim an der Ruhr, Almanya

M.Harde@rh-gmbh.com

ÖZETDemir ve Çelik Üretim tesislerindeki mevcut konvansiyonel Tav fırınları ve Elektrik ark ocakları bu sistemin esas tasarımını ve yerleşimini etkilemeden Reining Evaporatif Soğutma sistemi ile modernize edilerek optimum atık ısı değerlendirilmesi ve soğutma suyu tasarrufu sağlayarak tav fırınlarında 100 ton çelik kapasitesi için 8t/h kadar, elektrik ark ocaklarında ise 10t/h kadar buhar üretimi ile toplam 5MW elektrik enerjisi geri kazanımı mümkün olmaktadır. Bu arada sistemde soğutması için gerekli devri daim eden soğutma suyu açık sistemin sadece %30 kadarı yeterli ve kapalı soğutma sisteminin getirdiği avantajlarla da su kayıpları açık sistemin en fazla %10 kadarı olmaktadır.

Anahtar kelimeler: ENDÜSTRİYEL FIRINLARDA MODERN SOĞUTMA TEKNİKLERİ ve ENERJi GERİ KAZANIMI

IV.INDUSTRIAL FURNACES AND REFRACTORY SYMPOSIUMABSTRACTExisting Reheat Furnace and Electrical Arc Furnaces can be modified with a Reining evaporative cooling System without affecting the basic furnace design and this system enables optimum solution to recover waste heat energy and save cooling water, the steam generation reaches for a reheat furnace of a capacity 100 t up to m8t/h and EAF of a capacity 100t up to 10t/h here the power generation reaches up to 5MWe. The circulation cooling water in comparison of traditional cooling systems reduces up to the 30% and the loss of cooling water in cooling towers will be only the 10% of the open circuit cooling.

Keywords: INNOVATIVE COOLING SYSTEMS IN INDUSTRIAL FURNACES and ENERGY RECOVERY

1. INTRODUCTIONQingdao Jieneng Steam Turbine Group Co. Ltd (QJPS) specialized in manufacturing Steam Turbines up to 200 MW including low level recovery turbines.QJPS is a professional engineering company in Jieneng Group and in co-operation with Reining Heisskühlung GmbH Co. KG -Germany provides integrated services of power

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plant project, such as Design, Procurement, Installation, Operation, Training, Aftersales services. This strategic co-operation offers Turn Key delivery of:*Energy Generation and *Energy saving with the innovative Cooling and Waste Heat recovery of Industrial

Furnaces and Electric Arc Furnaces in Iron and Steel Plants. * Financing related investmentsEVO POWER is a consultancy and investment company with prime interest in environmentally sensitive projects

REINING HEISSKÜLUNG GMBH & CO. KG- REINING know-how from tradition and experience- Specialist in cooling systems for industrial furnaces for more than 60 years- More than 300 references world wide- Since 1994 a member of the Oschatz group an innovative and globally operating company with a 160 year tradition, experiences from hundreds of reference plants about waste heat recovery technology mainly for the steel making and non-ferrous metallurgy

1.2 Application of Evaporating Cooling Systems (ECS) in reheat furnaces:1.2.1 Walking beam furnaces: Figure 1.

Figure 1. ECS Application in Walking Beam Furnaces

Walking Beam Furnace will be equipped with swivel joints and the skid system works like a boiler which operates in forced circulation. Emergency situations as power failure can be easily controlled by diesel drives and/or turbine drives at the circulating pumps. Swivel joint units developed by Reining are applied to obtain optimum results regarding tightness and maximum operating reliability due to their construction and design.

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1.2.2 Pusher type furnaces: Figure 2.

Figure 2. ECS Application in Pusher Type Furnaces

Installed skid systems in Pusher Type Furnaces the absorbed heat can be make usable with the evaporative cooling system. Design, fabrication and inspection considering fatigue stress aspects guarantees also a maximum plant availability and safety. The evaporating cooled pusher type furnaces can be also be operated with natural circulation, i.e. without using circulation pumps.

1.2.3 ECS Benefits & Steam and Electric Power Generation Credit Example 300t PTF

Steam production skid system : 08÷18 t/h(depending on loss of skid insulation)Steam production evaporator : 10÷15 t/hSteam production total : 18÷33 t/hOperating hours : 7200 h/yearSteam amount : 129,600÷237,600 t/yearSteam credit : 15÷25 Euro/tBenefit steam : 1.9 ÷ 5.9 Million Euro/yearBenefit Electric Power generation : 2.5 ÷ 4.6 Million Euro/year

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2. Application of Evaporating Cooling Systems (ECS) in electric arc furnaces and Energy recovery: Figure 3.

2.1 ECS application on the heating surfaces for steam generation in EAF

Figure 3. Application of Evaporating Cooling Systems (ECS) in electric arc furnaces and heating surfaces used for steam generation

2.2 ECS – application on the EAF waste gas line: Figure 4

Figure 4: ECS application on the EAF waste gas line for steam generation

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2.3 EAF – steam using for vacuum plant: Figure 5

Figure 5: Possible using of the steam generated by the EAF cooling elements in ECS system.

If the plant is producing Stainless Steel or High alloy Steels the needed vacuum for EAF can be supplied by steam ejectors which use the steam generated by EAF cooling elements. 2.4 EAF – benefits / steam credit as an example of a 120 t EAF Figure 6.

EAF capacity : 120 t/chargesteam availability : Ø 70 – 120 kg/t/chargesteam quantity : Ø 8.4 – 14.4 t/chargecharge : Ø 4,800 charge/yearsteam amount : Ø 40,300 – 69,120 t/yearsteam credit : Ø 15 - 25 €/tbenefit : Ø 0.6 – 1.7 Million €/yearBenefit Electric Power generation: 1 ÷ 1.8 Million Euro/year

2.5 ECS – application / WHRU Figure: 6

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Figure 6: ECS application in WHRU in general

3. RESULT as major advantages of the ECS Figure 7.

Figure 7. Possibilities for using steam

Efficient, sustainable and energy recovery by:3.1 Steam using for energy via “Low Level Recovery Steam Turbine” which is specifically designed to operate with saturated steam at 30 bar, 210 C to generate electricity. These turbines are designed to operate by tolerating fluctuations in steam supply.3.2 Heating, 3.3 Process steam, 3.4 Refrigeration; delivering steam to absorption chillers, (6 ton of steam for 2.4 MW chilled water capacity)3.5 Air separation, driving HP compressor via steam turbine, (1 ton of steam for 300 m3 oxygen production)3.6 Driving e.g. of pumps and compressors3.7 Less energy consumption e.g.

3.7.1 Less temperature difference between furnace waste gas and cooling agent

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3.7.2 Operation partly in natural circulation possible meaning operation of the recirculation without the use of recirculation pumps 3.7.3Strongly reduced loss of water compared to an open cold water cooling system via cooling tower

3.8 Strongly increased lifetime of the cooling elements and by that strongly reduced operating cost due to reduced repair/maintenance and spare part providing due to

3.8.1 No corrosion on deposits inside the boiler tubes (operation with treated feed water)3.8.2 No corrosion on the gas side of the boiler tubes due to operation above the dew point3.8.3 Reduced thermal stress in the heating/cooling surfaces due to constant temperatures in the entire cooling circuit3.8.4 Much better heat absorption/transfer effects and/or specific cooling capacity3.8.5 General better operating safety due to

3.8.5.1 Extremely flexible behavior in case of fluctuating heat due to much higher specific heat absorption capacity, Figure 8.3.8.5.1 Suddenly occurring peaks can be balanced by discharge to atmosphere

Figure 8. ECS comparison with traditional water cooling systems in Reheat Furnaces and EAF

4. Payback time; considering above Benefits, Figure 9, the total investment of the ECS will be paid back in a few years due to

4.1 saving primary energy4.2 minimizing energy consumption

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4.3 saving cooling water4.4 improve productivity and plant availability

Considering the energy and water saving as well the steam using the investment of the ECS will be paid back in a few years!

Figure 9. ECS – benefits / return of investment

5. Environmental benefits; Reduction of CO2 emissions by using waste heat for steam generation contributes to environmental protection, for example;

5.1 For generation of 1 ton of steam by using Natural Gas, yields to approximate amount of 0,13 ton of CO25.2 By substituting of 1 MWH of thermal electric power yields to 0,6 ton of CO2

Thanks To

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We are very thankful to organization committees of previous congress and symposiums who built basis to this guide.

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