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Danalakshmi Paper Mills Ltd. Paper Industry Case Study. 60 Tonnes per day capacity Products : Newsprint, Cream wove, White Wove, Deluxe Newsprint, White printing. Energy Costs. Energy and Steam supplied from Cogeneration Plant Electricity cost : Rs 4.06 / Kwh
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Danalakshmi Paper Mills Ltd Paper IndustryCase Study • 60 Tonnes per day capacity • Products : Newsprint, Cream wove, White Wove, Deluxe Newsprint, White printing
Energy Costs • Energy and Steam supplied from Cogeneration Plant • Electricity cost : Rs 4.06 / Kwh • Steam( 5 bar) Cost : Rs 500 / Tonne • Annual Power Costs : Rs 3.63 Crores • Annual Steam Costs : Rs 1.2 Crores
Steam System Krima Paper M/c I (Drying Cylinders) 1 bar PRDV Paper M/c II (Drying Cylinders) Condensate 1.5 bar Steam 5 bar Condensate 1.5 bar
Condensate System Before Modified I Dryer II Dryer III Dryer IV Dryer Flash Steam Condensate Line Condensate Tank Flash Steam I Dryer II Dryer III Dryer Condensate Line Condensate Tank
Recover Flash Steam from Condensate Tanks –After Modified Steam, 5 Kg/cm2 Thermo compressor Krima 1.5 bar header Drying Cylinders Condensate Tank Steam, 5 Kg/cm2 Thermo compressor Investment - Rs. 4 Lakhs Annual Savings - Rs 4.48 Lakhs Payback Period - 1 year Condensate Tank
Drying Cylinders Steam Line 2.5 Kg/cm2 Pope, 11 Kw Calender, 52.5 Kw Condensate Line 2 Kg/cm2 Heat Loss due to Radiation in Drying Cylinders Annual Loss due to Radiation - Rs.5.44 Lakhs
1.2 m dia 100oC Avoid Heat Loss by Insulating the sides Drying Cylinders Steam Line 2.5 Kg/cm2 Pope, 11 Kw Calender, 52.5 Kw Condensate Line 2 Kg/cm2 Investment - Rs.
Energy Audit in Cogeneration Plant(5 MW Bio mass based) 1800 m3/hr Wet bulb temp - 28oC 8 Fan 2 nos 38 Kw each Hot water temp - 40oC Cooling Tower Cold water temp -32oC Condensate Tank (80oC) DM water Tank (32oC) Q -840 m3/hr H - 20 m P - 90 Kw Condenser 17.5 - 23 TPH 0.9 Kg/cm2 Q -25 m3/hr H -81 m P -15 Kw Triveni Turbines 5.5 MW, 11 Kv Extraction Steam 10 - 20 TPH 5 Kg/cm2 Hot well Tank (45oC) Turbine Q -30 m3/hr H - 62 m P - 15 Kw DOB Saw Dust Coal Rice Husk Lignite 37.5 TPH 40 Kg/cm2 415oC Deaerator (105oC) 160 Kw 105oC 220oC ESP Air Preheater 140oC Economiser 205oC 430oC Fluidsised Bed Boiler Cethar Vessels Ltd. (1996) 45 TPH 42 Kg/cm2g, 420oC Surface area - 1648 m2 4.56 m3/s 800 mm WC 3000 RPM 90 Kw 34 m3/s 230 mm WC 980 RPM 132 Kw Bed temperature 700oC 12.26 m3/s 700 mm WC 1480 RPM 132 Kw
Old FD Fan Operation DOB Saw Dust Coal Rice Husk Lignite 37.5 TPH 40 Kg/cm2 415oC 105oC 220oC ESP Air Preheater 140oC Economiser 205oC 430oC Fluidsised Bed Boiler Cethar Vessels Ltd. (1996) 45 TPH 42 Kg/cm2g, 420oC Surface area - 1648 m2 4.56 m3/s 800 mm WC 3000 RPM 90 Kw 34 m3/s 230 mm WC 980 RPM 132 Kw Bed temperature 700oC 12.26 m3/s 700 mm WC 1480 RPM 132 Kw FD Fans operated with 75 % damper opening
Modified FD Fan Operation with VSD DOB Saw Dust Coal Rice Husk Lignite 37.5 TPH 40 Kg/cm2 415oC 105oC 220oC ESP Air Preheater 140oC Economiser 205oC 430oC Fluidsised Bed Boiler Cethar Vessels Ltd. (1996) 45 TPH 42 Kg/cm2g, 420oC Surface area - 1648 m2 4.56 m3/s 800 mm WC 3000 RPM 90 Kw 34 m3/s 230 mm WC 980 RPM 132 Kw Bed temperature 700oC 12.26 m3/s 700 mm WC 1480 RPM 132 Kw VSD One FD Fan with 100 % damper opening Other FD fan with Variable Speed Drive
HIGH EFFICINCY FRP BLADE • More efficient than Al. blades • Efficiency is high due to Aero dynamic profile of blades • Easy to install • Better moisture resistance. • Annuals savings Rs. 1 Cr. Against Invst.-Rs.50 lacs
REFRIGERATION SYSTEM (ICE Bank System) Chilled water from process 5 to 7°C Pasteurization PROCESS PLANT Ammonia liquid at -20 °C ICE bank system Receiver Ammonia vapor Chilled water to process 1°C PHE Condenser Compressed air Ammonia Compressor 270 HP,152 TR x3Nos Roots Blower Cooling Tower
Energy Use Mix Total Energy Use 156.23 Giga Calories
7. CONVERSION OF FO FIRED BOILER TO BRIQUETTE FIRED EXTERNAL FURNACE BOILER ECONOMICS OF FUEL CONVERSION • Briquette has GCV up to 4200Kcal/kg. • 2.2 kgs of briquette are equivalent to 1 liter of furnace oil. • Price of furnace oil =18.Rs/ lit • Price of briquette = 4 Rs. /kg • Substitution will result in saving of 10 Rs. /lit. of F.O. fired. • Saving of > 60% in operating cost Conversion requires only removal of its existing burner-blower assembly, adding a grate to burn the briquette in same combustion chamber and installation if ID fan. Adiabatic flame temperature with solid fuel is lesser by 200 to 300oC. Thus in spite of on addition of extra furnace usually up to 70% capacity can be achieved
Briquettes • Briquettes , Bagasse which is a residue of sugar cane after sugar extraction. The bagasse is dried in the Sun and extruded. The compaction gives bulk density up to 1100 Kg/m3, due to which 10 tons of briquette can be loaded in single truck. • Being cellulosic in nature briquettes can be easily burnt in boiler without clinker formation.
3. Saving by using Briquette instead of Firewood Annul cost for Firewood usage in Boiler and Thermic Fluid Heater: Annual firewood consumption = 12T/day * 6 * 52 = 3744T/year Annual cost for firewood = 3744T * Rs.1700/T = Rs.63, 64,800/year Annul cost for Briquette usage in Boiler and Thermic Fluid Heater: Annual Briquette consumption = 4T/day * 6 * 52 = 1248T/year Annual cost for Briquette = 1248T * Rs.4000/T = Rs.49, 92,000/year Annual cost saving by fuel switching = 63, 64,800 – 49, 92,000 = Rs. 13, 72,800/year Invstment for new grate to withstand High Temperature = 2. Lakhs Pay back period =2/13.7 = 2 months
Firewood to Briquette Thermic Fluid heater Thermic Fluid heater Boiler 3TPH Boiler 3TPH Fire wood Briquettes
Use steam for furnace oil preheating in power plant Annual Savings – Rs.1.28 crores 60OC Furnace oil storage tanks DG Power Plant LP Steam 120OC Steam line heaters HP Steam
Use vapour absorption system for chilled water Steam 36 TPD Chilled water tank 200 TR Power drawn by existing ammonia compressor – 150 kW • Additional 200m3/hr • Cooling water is required • Net power for • CTpump & CT fan – 30 kW • Power savings – 120 kW Plant Annual Savings Rs.30 lakhs
Heat integration of product cooler with weak acid Existing Modified Weak Acid 50oC 13.5 m3/hr Weak Acid 40oC Weak acid preheater Condensate 80oC Condensate 50oC 2 m3/hr Weak Acid 40oC Weak Acid 50oC New heat exchanger 2 m3/hr Hot Acid 124oC Cooled Acid 42oC Hot Acid 124oC Cooled Acid 42oC Z5 acid cooler Cooling water 30oC Cooling water 34oC 33 m3/hr
Textile Industry Case Studies
Boiler Efficiency Improvement by damper control Thermax Boiler 6 TPH 10.75 Kg/cm2 Coconut shell fired Economiser Dust Collector Primary Air Fan Secondary Air Fan 14 % Damper 9 % Hopper Induced Draft Fan Coconut shell crusher
Fuel Savings due to Boiler Efficiency Improvement • By damper control O2 in flue gas brought down from 14 to 9 % • Correspondingly excess air from 200 to 75 % • Savings in coconut shell consumption – 5 % Annual Savings – Rs. 3.5 Lakhs
Energy saving in Boiler ID fan by speed reduction through pulley change 10” 26 kW 8” 1470 RPM 1181 RPM 14 kW 10” 6” 1470 RPM 882RPM Motor Puly PumpPully Power Consumption
Stafi Drier Steam 6 Kg/cm2 Steam 6 Kg/cm2 Radiator Radiator Suction Suction Roots Blower 1620 m3 2000 mm WC 19 Kw Roots Blower 1571 m3 3000 mm WC 22 Kw
Power Supply Sources Windmills Wheeling ,5% Avg,5.0 lakhs unit/month TNEB grid 9.0 lakhs unit/month Rane Brake Linings Ltd Chennai CD- 2300 kVA Standby DG sets 1.5%
Annual Energy Bill Rs. 4.81 Crores
2. Replace reciprocating air compressor with Energy efficient Screw compressor Energy Saving Calculation Annual Operating hours = 7500 hrs Measured consumption = 31.6kW Energy saving (30% basis)=31.6*0.3 = 9.48 kwh Annual energy savings=(9.48*7500hr/yr) = 71,100kWh Annual cost savings (Rs 4/unit) = 71100*4 = Rs.2.84 lakhs Investment =Rs.4.0 lakhs Payback period =1.4 year
12 9 8 8 3. Reduce loading and unloading setting in small compressors Location Range Rated Kw Measured %Load ΔP Remarks R&D 8.0-11.0 7.5 10.9 123.5 3.0 Over load R&D 8.0-12.0 7.5 10.8 122.4 4.0 Over load Annual energy savings (5.4x5000hr/yr) =27,000 kWh Annual cost Savings (Rs 4/unit) =Rs.1.08 lakhs Investment =nil Payback period =immediate
Solar water heater for preheating feed water(Canteen) Steam, 120oc Cooking Ex gas Steam Boiler Washing vessel Future purpose 100 lit/day Diesel Water, 85oc
Regulate with dampers in each equipment Avoid parallel operationProvide VSD Cyclone VSD 75 hpx1No 30 hpx3 No blower Pneumatically actuated dampers • Existing: • No dampers, Suction remains even when M/c not operating • Common suction and Unbalanced parallel operation • Proposed: • Provide dampers • Install Single Fan of 75 hp with VSD
7. Replace Old Window Air-Conditioners with New Energy Efficient Air-Conditioners OLD AIRCONDITIONER =2.5KW NEW ENERGY EFFICIENT =1.86 KW Saving per m/c =0.64kw Effective operating hours =10 hrs Energy savings/yr(10x0.64x312) =1997 Annual cost saving/year Rs 4/unit =7987 Annual maintenance cost saving =1750 Investment for 11.5 TR New machines =17500 Pay back =1.8 year Annual cost saving for 10Acs =Rs.97,380
Summary of Energy Saving Recommendations Overall Cost Reduction Potential = 8% of Annual Energy Bill
Energy Consumption Indicators in Energy Intensive Indian Industries
AVERAGE SPECIFIC POWER / THERMAL ENERGY CONSUMPTION IN INDIAN CEMENT UNITS
ENERGY SAVINGS POTENTIAL IN CEMENT INDUSTRY
Best SEC Achieved By An Indian Cement Unit ELECTRICAL • Specific power consumption is 62.44 kWh per tonne of cement THERMAL • Specific thermal energy is 687 kCal/kg clinker