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ENERGY SAVING IN STEAM GENERATION AND TRANSPORT IN FOOD INDUSTRY B. K. Kumbhar B. K. Kumbhar 6/10/20141.

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Presentation on theme: "ENERGY SAVING IN STEAM GENERATION AND TRANSPORT IN FOOD INDUSTRY B. K. Kumbhar B. K. Kumbhar 6/10/20141."— Presentation transcript:

1 ENERGY SAVING IN STEAM GENERATION AND TRANSPORT IN FOOD INDUSTRY B. K. Kumbhar B. K. Kumbhar 6/10/20141

2 2 Introduction Energy – Important Sources Exhausting at rapid rate prices increasing day by day Energy cost 5% of total production cost Neglected

3 HOT WATER OR STEAM? More accurate control without costly control equipments More accurate control without costly control equipments Efficient processing and high standard of hygiene with maximum fuel economy Efficient processing and high standard of hygiene with maximum fuel economy Thermal efficiency of hot water boilers is more and fuel requirement is about half Thermal efficiency of hot water boilers is more and fuel requirement is about half Savings in water, maintenance and labour requirements, Savings in water, maintenance and labour requirements, Maximum recovery is possible Maximum recovery is possible Lower reconstruction and capital costs Lower reconstruction and capital costs Lower instrumentation costs Lower instrumentation costs Obviation of the use of chemicals Obviation of the use of chemicals High heat and moisture release is eliminated resulting a simple ventilation system High heat and moisture release is eliminated resulting a simple ventilation system Improvement in safety Improvement in safety

4 6/10/20144 Boiler Input-Output Fuel Air Water Fuel Air Water Boiler * Combustion * Heat Transfer SteamFlue gasBlowdown

5 6/10/20145

6 6 1. STEAM GENERATION 1.1 Fuel 1.1 Fuel 1.2 Air 1.2 Air 1.3 Water 1.3 Water A. Treatment of water A. Treatment of water B. Preheating of feed water B. Preheating of feed water C. Use of condensate as feed water C. Use of condensate as feed water 1.4 Flue gas 1.4 Flue gas a) Temperature of flue gas a) Temperature of flue gas b) Quantity of flue gas b) Quantity of flue gas c) Condition of heat transfer surface in the boiler c) Condition of heat transfer surface in the boiler 1.5 Blowdown 1.5 Blowdown 1.6 Radiation and convection losses 1.6 Radiation and convection losses

7 6/10/ Fuel Quality of Fuel- Sulphur, Moisture content Fuel oil Fuel oil Burners – Atomization - Air - Specific heat is less - Air - Specific heat is less - Steam – Specific heat is more- twice - Steam – Specific heat is more- twicePreheating Coal CoalPulverization Natural gas Natural gas

8 6/10/ Air Quantity Quantity Sufficient amount

9 6/10/ Water Treatment of water Ca, Mg salts- scale formation- less heat transfer Treatment of water Ca, Mg salts- scale formation- less heat transfer 0.79 mm – Increased fuel consumption – 7% 2.82 mm – 16% Oxygen and CO2, Low pH- Corrosion & Erosion treatment of feed water outside the boiler within the boiler (internal treatment) within the boiler (internal treatment) chemicals which remove hardness or scale forming materials that can not be removed by filtration. chemicals which remove hardness or scale forming materials that can not be removed by filtration. Oxygen and carbon dioxide - vacuum deaerators steam scrubbing deaerators steam scrubbing deaerators

10 6/10/ Water contd Preheating of feed water Temperature of feed water- efficiency Preheating of feed water Temperature of feed water- efficiency 6 C increase- 1% fuel saving 6 C increase- 1% fuel saving Economizer for preheating Economizer for preheating Use of condensate as feed water Use of condensate as feed water Reduction in use of chemicals for water softening Reduction in use of chemicals for water softening Preheating is prevented Preheating is prevented Reduced water requirement Reduced water requirement Temperature increase from 15.5 to 35 C with 100% condensate return reduced 4.2% fuel Temperature increase from 15.5 to 35 C with 100% condensate return reduced 4.2% fuel

11 6/10/ Flue gas Loss of energy> 18% Temperature of flue gas Temperature of flue gas Temperature 70 C more than water temperature Temperature 70 C more than water temperature Clean surface Clean surface Use of economizer- 10% fuel saving- payback period 1 year Use of economizer- 10% fuel saving- payback period 1 year Reduction of 22 C 1% increase in efficiency Reduction of 22 C 1% increase in efficiency

12 6/10/ Quantity of flue gas Quantity of flue gas Proper air-fuel ratio Temperature Barometric pressure Humidity Specific gravity and viscosity of the fuel oil Table 1 Suggested levels of excess air Table 1 Suggested levels of excess air FuelBurner Excess air, % Coal Spreader stoker Fuel oilRegister type5 10 Multifuel type10 20 Natural gasRegister type5 10 Multifuel7 12 Multifuel7 12 Reduce excess air Reduce excess air Keep CO 2 level above 13% or O 2 level below 3.5% 3% change in CO 2 level increases 4% in efficiency 3-5% saving in automated control devices

13 6/10/ Condition of heat transfer surface in the boiler Condition of heat transfer surface in the boiler Clean surface – more heat transfer Clean surface – more heat transfer Regular cleaning of all surfaces Regular cleaning of all surfaces Standstill for few months corrosion of boiler due to residual moisture. Remove residual moisture with dryain Residual moisture in dry air <30% Residual moisture in dry air <30%

14 6/10/ Blowdown Affects Affects Make up water - Heat loss in blowdown Chemicals requirement Frequency Frequency Quantity Quantity Heat recovery Heat recovery

15 6/10/ Advantages of automatic Blowdown Discharge less heat Discharge less heat Reduces treatment chemicals Reduces treatment chemicals Decrease make up water Decrease make up water About 20% saving from changeover About 20% saving from changeover

16 6/10/ Radiation and convection losses Significant loss if not insulated Significant loss if not insulated 1.5% loss in well insulated 1.5% loss in well insulated capacity utilization. capacity utilization. Less- Radiation loss more Less- Radiation loss more Boiler operation few hours a day Boiler operation few hours a day Use boiler stack damper Use boiler stack damper Close boiler house doors & windows Close boiler house doors & windows

17 6/10/ STEAM TRANSPORT 2.1 Quality steam 2.1 Quality steam 2.2 Insulation 2.2 Insulation 2.3 Correct piping 2.3 Correct piping 2.4 Strainers, steam traps and steam separators 2.4 Strainers, steam traps and steam separators

18 6/10/ Quality steam Steam Quality Steam Quality Amount of water droplets present Amount of water droplets present Quality steam Quality steam Better heat transfer Better heat transfer Long life of the system Long life of the system Dry, Clean, free from non condensable gases, right pressure and right temperature Dry, Clean, free from non condensable gases, right pressure and right temperature Dirty steam Dirty steam Erode and corrode value Erode and corrode value Clogging of ports body Clogging of ports body Leakage through valves Leakage through valves Non condensable – limit steam flow less heat transfer Non condensable – limit steam flow less heat transfer 0254 moss film thickness – 3.3m of cu panel 0254 moss film thickness – 3.3m of cu panel Carbon di-oxide-carbonic acid- corrosion Carbon di-oxide-carbonic acid- corrosion Oxygen – accelerates corrosion Oxygen – accelerates corrosion

19 6/10/ Insulation Personal protection Personal protection Condensation prevention Condensation prevention Process temperature control Process temperature control Heat loss prevention Heat loss prevention Poor insulation – Up to 50% heat loss To reduce loss of heat To reduce loss of heat Economic thickness – cost of fuel & insulating material installation cost, Economic thickness – cost of fuel & insulating material installation cost, pipe size, annual hours of operation, boiler efficiency, pay back period. Replace damaged insulation Replace damaged insulation Insulate values and flanges – uninsulated flange heat loss from 60 cm of untagged pipe. Insulate values and flanges – uninsulated flange heat loss from 60 cm of untagged pipe.

20 6/10/ Correct piping Pipe size * Amount of steam to be transported * Pressure * Pressure Oversize pipe Pressure drop increases, Pressure drop increases, Temperature. Decreases – heat transfer reduction Temperature. Decreases – heat transfer reductionLength Just sufficient Just sufficient Excess length & redundant piping increases loss of heat Excess length & redundant piping increases loss of heat condensation of stem, corrosion of pipe condensation of stem, corrosion of pipe

21 6/10/ Strainers, steam traps & steam separators Strainers Strainers Upstream of values and steam trafs to protect from clogging with dust & dire. Upstream of values and steam trafs to protect from clogging with dust & dire. Steam traps Steam traps to remove condensate and non condensable correct size of steam trap. to remove condensate and non condensable correct size of steam trap. Steam separator Steam separator To get drier steam – water dropter To get drier steam – water dropter Direction of flow path to changed Direction of flow path to changed Accumulated water droplets sent to stem traps Accumulated water droplets sent to stem traps Near a point of usage Near a point of usage

22 6/10/ STEAM FOR PROCESSING Quality steam Quality steam Efficient processes and equipment Efficient processes and equipment Collecting condensate Collecting condensate Boiler feed water Boiler feed water Cleaning the equipment Cleaning the equipment Heating process streams Heating process streams

23 6/10/ WHAT CAN BE DONE? a. Calculate the total heat, Q, present in the fuel by knowing the calorific value (cv) of the fuel and quantity of fuel (m) used. a. Calculate the total heat, Q, present in the fuel by knowing the calorific value (cv) of the fuel and quantity of fuel (m) used. b. Calculate the process heat requirement. This will include heat required for heating, evaporation and drying duties as the case may be. b. Calculate the process heat requirement. This will include heat required for heating, evaporation and drying duties as the case may be. Overall thermal efficiency of plant Overall thermal efficiency of plant Calculate total heat required in the plant Calculate total heat required in the plant Calculate total heat available in the fuel Calculate total heat available in the fuel Boiler efficiency – 80% Boiler efficiency – 80% Transport efficiency – 95% Transport efficiency – 95% Process/thermal efficiency – 80% Process/thermal efficiency – 80% No. of plants – 61% No. of plants – 61%

24 6/10/ Boilers Large boiler – 75-85% efficiency Gas fired boilers – 92 % efficiency Efficient boiler operation and maintenance saving up to 35% Energy savings up to 20% in new boilers Efficiency Combustion efficiency - how efficiently the boiler burns the fuel Combustion efficiency - how efficiently the boiler burns the fuel Steady – state efficiency – under full load Steady – state efficiency – under full load Seasonal efficiency – over the entire heating season Seasonal efficiency – over the entire heating season

25 6/10/ Improving Efficiency Energy saving devices Energy saving devices - Economizer - Economizer - Condensate recovery - Air preheaters - Turbulators - Oxygen trim controls - Load controls - older pneumatic control system - Analog control systems - Digital computer based distributed control systems Modern, multiple burner control and trim control – 3-5% saving

26 6/10/ Selecting a new Boiler System Replace old biter – 15 years old with a high efficiency model – save up to 35% Replace old biter – 15 years old with a high efficiency model – save up to 35% Older boilers oversized, inefficient Older boilers oversized, inefficient Multiple boiler systems more efficient than single boilers Multiple boiler systems more efficient than single boilers Pay back period 2-4 years Pay back period 2-4 years

27 6/10/ Fire Side Maintenance Minimize excess air – Regular monitoring (weekly) of gas oxygen or carbon dioxide content Minimize excess air – Regular monitoring (weekly) of gas oxygen or carbon dioxide content Keep heat transfer surfaces clean Keep heat transfer surfaces clean - Soot build up on tubes – insulation - Elevated stack temperature Water side Maintenance Reduce scale formation Reduce scale formation Scale build up – loss by as much as 10-12% 1/8 inch. – 2-3% loss in boiler efficiency Scale build up – loss by as much as 10-12% 1/8 inch. – 2-3% loss in boiler efficiency

28 6/10/ Reduce boiler pressure – Reduction in fuel consumption and stack temperatures Reduce boiler pressure – Reduction in fuel consumption and stack temperatures Insulate Boiler and boiler piping 2.5 cm insulation – 80-90% reduction in heat loss Insulate Boiler and boiler piping 2.5 cm insulation – 80-90% reduction in heat loss Optimize Boiler blowdown waters Optimize Boiler blowdown waters Blowdown heat recovery Blowdown heat recovery - Blowdown rat4e 4-8% of total steam generated - AS high as 10% Repair of steam leaks Repair of steam leaks Steam leaks develop around valve stems pressure regulators and pipe joints Small leak represents a significant loss of energy Repair of leak have a short pay back (2-3) months. Repair of leak have a short pay back (2-3) months.


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