cogeneration project opportunity
TRANSCRIPT
Cogeneration project opportunity
KMITL COMBUSTION LAB
Introduction to cogeneration
KMITL COMBUSTION LAB
• conventional steam production in industrial
• What if we place Micro-turbine before the boiler ?
Air inlet
NGV inlet
Introduction to cogeneration
KMITL COMBUSTION LAB
• What if we place Micro turbine and afterburner before the boiler ? • High value by product electrical generation • Generating by product electrical power with the same cost of fuel heating value• To generate by product electrical power while sustaining boiler capacity and
efficiency
Micro turbine exhaust manifold
After burner
Exhaust stack
Air inletNGV inlet
Steam generation
Electrical generation
Cogeneration introduction ( Micro turbine application )
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Duct combustor
Micro turbine & generator unit
Exhaust manifold duct To boiler burner
Boiler unit
Cogeneration introduction ( piston engine application )
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• Considerable higher thermal efficiency ( around 40-45% ) • More complicate thermal recovery • Exhaust direct combustion to boost temperature may not capable
Example of cogeneration application
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• Electrical & hot water generation ( commercial set ) • Electrical & steam generation with direct burner • Electrical & cold water generation (trigeneration)• Integration with ORC or Rankine bottom cycle ( >40% electrical efficiency )
Capstone with ORC integration
C65 electrical & hot water generation commercial unit
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Capstone C65 energy analysis
KMITL COMBUSTION LAB
• Electrical & hot water generation, commercial package
246.67 KWNGV burn C65
turbine
65 KW electrical generation
120 KW hot water generation
61.67 KW stack loss
Capstone C65 business analysis
KMITL COMBUSTION LAB
• Electrical & hot water generation, commercial package
398.31baht/hrNGV burn C65
turbine
240.5 baht/hr electrical generation
193.77 baht/hr hot water generation
0 baht /hr
• profit = (240.5 + 193.77) – 398.31 = 35.96 baht / hr = 315,009.6 baht / yr / unit
Note : NGV cost 17 baht/Kg , Electrical cost 3.7 baht / Kwh NGV heating value @ 37.9 MJ/Kg
C65 Electrical & steam generation with afterburner
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Energy analysis (compare with conventional boiler system )
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• Energy flow with conventional boiler
80 % boiler efficiency 85.4 KW stack loss
427 KW (fuel burn)
341.6 KW of steam generation
Business analysis (compare with conventional boiler system )
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341.6 KW of steam generation
• Money flow with conventional boiler
750 baht/hr (NGV burn)
80 % boiler efficiency 20 % stack loss
• pay 750 baht / hr for NGV fueled to generate steam 341.6 KW
Note : NGV cost 17 baht/Kg , Electrical cost 3.7 baht / Kwh NGV heating value @ 37.9 MJ/Kg
Energy analysis ( C65 CHP application with afterburner )
KMITL COMBUSTION LAB
• Energy flow with CHP integrate system (micro turbine )
246.67 KW (fuel burn)
29 % GT efficiency 80 % boiler efficiency
341.6 KW of steam generation
65 KW electrical generation
181.67 KW (exhaust gas)
246 KW (After burner)
427 KW (flue gas)
85.4 KW stack loss
Business analysis ( C65 CHP application with afterburner )
KMITL COMBUSTION LAB
• Money flow with CHP integrate system (micro turbine )
400 baht/hr (fuel burn)
29 % GT efficiency 80 % boiler efficiency
341.6 KW of steam generation
240 baht/hr electrical generation
400 baht/hr (After burner)
427 KW (flue gas)
85.4 KW stack lossPay 800 baht to generate 341.6 Kw Generate 240 baht of electrical powerProfit = 750 - (800 -240 ) = 190 baht / hr /unit = 1,641,600 baht / yr /unit
Thermal process analysis on electrical and steam generation with direct burner
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• Typical steam generation process o Air / fuel was mixed and burned with burnero Combustion hot gas temperature is nearly at adiabatic flame temperatureo Heat transfer characteristic in fire tube boiler is strongly depends on flame
temperature
• Heat transfer in fire tube boiler o Radiation ( heat up tube surface of fire tube and hot gas ) o convection ( Transfer hot gas energy to water cooled tube surface )o conduction ( Transfer energy from hot side tube surface to cool side )
• Hot gas temperature parameter is effect on heat transfer characteristic, boiler
capacity and boiler efficiency
Evaluation on boiler performance and efficiency on combustion gas temperature and velocity (example)
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• Employ dimensionless approach o Heat transfer through the tube wall electrical circuit analogy
o Fire tube boiler TA is known, temperature of the combustion gas o Water temperature TB is know, temperature saturated water o h1 is known by dimensionless approach correlation of …o h2 can remodel to conduction analogy using K water approach or other
available correlation can be employed. o Effect of radiation will resulting in raising of T1
Hot gas temperature analysis on electrical and steam generation with direct burner
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• cogeneration application Exhaust gas temperature was boosted by direct burner
• thermodynamics analysis (energy conservation ) The boosted exhaust gas temperature = (1-n)*(qin ) + (qad –qin ) / Cp air Typical flue gas temperature = qad /Cp air
p
v
Thermal process analysis on electrical and steam generation with direct burner
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• Micro-turbine with 30% thermal efficiency • There is 15 % in temperature drop comparing to conventional burner ( for 2000K
adiabatic temperature fuel ) • How can we estimate boiler performance and capacity deteriorate due to this effect
?
Business opportunity analysis (compare with conventional boiler system )
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80 Joule of steam generation • Money flow with conventional boiler
100 baht (fuel burn)
80 % boiler efficiency 20 % stack loss
• Money flow with CHP integrate system (micro turbine )
xx baht (fuel burn)
xx baht electrical generation
29 % GT efficiency
xx baht (fuel burn)
80 % boiler efficiency
80 Joule of steam generation xx joule (GT exhaust)
Heat transfer scaling law for systems prediction
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• Example NGV fueled Micro-turbine with 30% thermal efficienc
Future development opportunity
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