Furnace Performance AssessmentA Case Study

By Chandan Sudip, IISWBM KolkataFor

Workshop on Enterprise Energy Management

Organized by AEE Delhi-NCR ChapterOn 28Apr2012 at YMCA Greater Noida

Part of BEE’s SME EE Program for25 SME clusters

Energy Team of IISWBM, Kolkata in 2010 Team leader: Dr B K Choudhury, Associate

Prof Chandan Sudip, IISWBM associated as

trainee Cluster: 100 Galvanizing Units at Howrah

(WB)

Background of the Case Study

Production: 1200Tons of job p.a. Annual Zinc consumption:250Tons

(Rs312Lac) Annual FO consumption: 72000 litres

(Rs21.6Lac) Annual electric

consumption:2.15LacKWh (Rs16Lac) Cost Ratios: 74% zinc, 8% energy/fuel,

18% others Total annual production cost; Rs433Lac

Production and Energy Costs

Facility under study is engaged in galvanizing iron fittings used in electric lines & insulators

Installed capacity: 1300Tons of jobs p.a. Production: 1200Tons of jobs p.a. Furnace: FO Fired batch type Capacity: 0.5Tons of jobs per hour Diameter of Furnace: 45Ft

Description of Facility & Furnace

Acid Pickling the job Rinsing the job with water Drying the job over coal based furnace Melting Zinc with FO fired furnace Dipping the job in Zinc bath Water Quenching of the job

Galvanization Process in Brief

Close View of Furnace

Another View of Furnace

Jobs waiting for Galvanization

Zinc Slabs waiting to be melted

Average ambient temp over a year: 40⁰C Average Burner Temp: 475⁰C Temp of Zinc Bath: 400-455⁰C⁰C Average Temp of zinc bath: 440⁰C Temp of Job coming out of Zinc bath: 140⁰C Temp of Flue Gas: 120 ⁰C % Oxygen in Flue Gas: 5.8% Excess Air(calculated): 38%

Measured Parameters

Annual Production: 1200 Ton Annual FO Consumption: 72000 litres Sp. Gr of FO: 0.93 Mass of FO=72000x0.93=66960Kg GCV of FO: 10500KCal/Kg =44100 KJ/Kg Input Heat=66960x44100= 29529,36,000KJ Mass of zinc: 250Tons=250,000Kg Sp. heat of zinc: 0.30KCal/Kg/⁰C (For sensible heat+latent heat of melting)

Temp Difference=440-40=400 ⁰C Output Heat in zinc=250000x0.3x400=300,00,000KCal=126000000KJ Mass of Iron in job=1200,000Kg Sp. heat of iron: 0.46KCal/Kg/0c/⁰C Temp Difference=140-40=100 ⁰C Output heat in iron=1200000x0.46x100=55200000KCal=231840000KJ Total output heat(KJ)=1260Lac+2318.4Lac=3578.4Lac KJ Furnace Efficiency=Output/Input=3578.4/29529.36=12.12%

Furnace Efficiency Calculation

Existing Excess Air(EA): 38% Desired Excess Air(EA): 10% Reduction in % EA : 28% per 1% reduction in EA, Av. efficiency rise: 0.6% Expected efficiency rise=28x0.6=16.8%, say 15% Improved efficiency=12+15=27%

Recommended Conservation Measure-1Excess Air Control

Pre-heating of combustion air Improved insulation over furnace walls

Other Conservation Measures

I am a final year student of Energy Management at IISWBM,Kolkata

I am accessible at mobile 09038647504 and email-chandansudip@yahoo.co.in

chandansudip36@hotmail.com

Thanks