Post on 12-Oct-2020
© Confederation of Indian Industry
Energy Conservation
Opportunities in
Boilers & Steam system
© Confederation of Indian Industry
Centre of “Excellence” for Energy, Environment, Green Buildings, Renewable energy, Water & Climate change activities in India
CII – Sohrabji Godrej Green Business Centre, Hyderabad
A unique Public – Private Partnership( CII, Govt of Andhra Pradesh, USAID and Pirojsha Godrej Foundation )
© Confederation of Indian Industry
Agenda
v Approach for energy conservation
Ø Example from sports
v Opportunities for energy efficiency
improvement – Case studies
© Confederation of Indian Industry
Two Examples from Sports…
v Sergei Bubka - Ukranian pole vaulter
q I person to cross 6-m mark
q Continuously improved
q Broke his own records > 14 times!
Efficiency Improvement - Continuous
Olympic Gold Medal Winners in High Jump
2.6
2.4
2.2
2
1.8
1.6
1900 1920 1940 1960 1980
Scissors
Western Roll
Straddle
FosburyFlip
Source: Pascale
v Fosbury
q Basically a Gymnast - Not successful
q Applied principles of Gymnastics to High
Jump
q Result - A Quantum Jump !!!
Adopt the Latest Technology Inputs from Other Industries - Innovation
Inference from Sports…
© Confederation of Indian Industry
© Confederation of Indian Industry
Few Case Studies…
Arrest air infiltration through APH
ESP
ESP
Q –122.56 M3/sH –406 mmM –725 kW
2.3 % O2
APH
4.6 % O2
6.7 % O2
6.8 % O2
Unit I
© Confederation of Indian Industry© Confederation of Indian Industry
Observation - Air infiltration in Air Preheater
151338151339TempoC
3006CO (ppm)
14.316.413.815.6% CO2
2.8
Inlet
APH -B
4.74.62.3% O2
OutletOutletInlet
APH -AUnit –1
v Online flue gas analyzer available
Ø Before & after air pre heater
v Combustion analysis carried out
Ø Using portable combustion analyser
© Confederation of Indian Industry© Confederation of Indian Industry
Air infiltration in Air Preheater
155325156323TempoC
0000CO (ppm)
13.413.613.314.1% CO2
4.9
Inlet
APH -B
5.44.94.6% O2
OutletOutletInlet
APH -AUnit –2
© Confederation of Indian Industry© Confederation of Indian Industry
Air infiltration in Air Preheater
Air preheater1 Kg flue gas2.3 % O2
X Kg of air20.9 % O2
1+ X Kg of Flue gas4.6 % O2
v Quantity of air infiltrationØ Unit -1
Ø APH - A - 14.1 %Ø APH – B - 11.72 %
Ø Unit –2Ø APH –A - 1.8 %Ø APH – B - 3.2 %
© Confederation of Indian Industry© Confederation of Indian Industry
v Unit – 1 quantity of air ingress is significant
v Unit -1 due for maintenance
v Arrest air preheater leakage during the maintenance
v Online monitoring available before & after APH
Ø Periodically cross check using portable analyser
v Equivalent coal saving - 0.5 tons/hr
Air infiltration in Air Preheater
© Confederation of Indian Industry
v Holes in ID fan duct bends & corners
Ø Erosion due to flue gas especially in
locations where direction of flow changes
v Increased air infiltration & hence increased
ID fan power consumption
Methods for reducing air infiltration in flue gas side
© Confederation of Indian Industry
Ceramite coating in the bends
© Confederation of Indian Industry
Castable refractory for reducing Erosion
© Confederation of Indian Industry
v Covered with “Thermal Fabric Expansion”
Ø Special material-can withstand temperature upto 700-
800oC
Ø Sandwiched with “Glass Wool”
Ø Can be installed “ON line”
Methods for reducing air infiltration in flue gas side
© Confederation of Indian Industry© Confederation of Indian Industry
v What is the effect of vacuum on turbine performance?
v Turbine capacity - 37 MW
v Present load - 15 MW
loaded less than 50% of the capacity
v During normal operating condition very low vacuum has been
achieved
Ø Achieved vacuum - 0.04 kg/cm2 (a)
Ø Design vacuum - 0.1 kg/cm2 (a)
2.Operate the condenser at design vacuum level
© Confederation of Indian Industry© Confederation of Indian Industry
v Effect of lower vacuum compared to design
v Life of the turbine
Ø Reduction in dryness fraction of exhaust steam
q Turbines normally designed for 0.86 dryness fraction
Ø Increased pitting on LP turbine blades
v Increase in energy consumption
Ø Velocity of steam flow increases
Ø Exhaust loss increases
Operate the condenser at design vacuum level
© Confederation of Indian Industry© Confederation of Indian Industry
Turbine Exhaust loss curve
© Confederation of Indian Industry© Confederation of Indian Industry
Operate the condenser at design vacuum level
6.52010.04
3.81630.05
3.0137.50.06
2.4104.80.08
2.593.80.09
2.8850.1
Exhaust loss kCal/kg
Velocity (m/sec)Pressure (kg/cm2)
© Confederation of Indian Industry© Confederation of Indian Industry
v The exhaust loss is the lowest at 0.08 kg/cm2 (a) vacuum
v How to maintain the design vacuum
Ø Reduce the quantity of water supply
Ø Optimise the operation of cooling tower fan
Ø Control on Ejector
v Equivalent reduction in steam consumption - 300 kg/hr
Operate the condenser at design vacuum level
Annual Saving - Rs 27.00 Lakhs
© Confederation of Indian Industry
v Waste heat recovery boiler in operation
v Operating steam parameters
Ø Pressure - 38 kg/cm2
Ø Saturated steam
Ø Capacity - 12 – 13 tons/hr
v Steam utilised for turbo driven circulating water
pump & exhaust steam for process
3. High efficiency Micro turbine
© Confederation of Indian Industry
v Power generation potential partially
utilised
v Specification of circulation water pump
Ø Flow - 280 m3/hr
Ø Head - 48.9 m
v Power requirement - 60 kW
High efficiency Micro turbine
© Confederation of Indian Industry
v Conventional turbine with exhaust in
superheated condition
Ø Turbine single stage
v Power generation potential – 75 kW
v Latest double stage turbine gives excellent
potential
Ø Power generation opportunity - 500 kW
Power generation potential
© Confederation of Indian Industry
Steam and Power Costing
~Two stage turbine
Pr – 38 kg/cm2 (g)Temp – satFlow – 12 tons/hr
Pr – 5 kg/cm2 (g)Temp –158oCDryness fraction –0.93
500 kW
Excellent potential for power generation
© Confederation of Indian Industry
v Supplier guaranteed upto - 560 kW
v Existing circulation water pumps needs to
be electrical motor driven
v Net power generation - 500 kW
Power generation potential
Annual Saving - Rs 105.60 LakhsInvestment - Rs 70.00 LakhsPayback period - 8 months
© Confederation of Indian Industry
4.Steam Ejector / Vacuum Pump
Condenseror
vessel
CW
Existing
Pro
pose
d
Steamejector
Steam
Water ringvacuum pump © Confederation of Indian Industry© Confederation of Indian Industry
v Presently steam ejector is in operation
v Design specification
Ø Working steam pr - 10 ata
Ø Steam temperature - 350oC
Ø Steam consumption - 1000 kg/hr
Ø Suction pressure - 0.035 ata
Ø Capacity of dry air - 20.4 kg/hr
Ø Dry air + water vapour - 65.4 kg/hr
Install vacuum pump in lieu of steam ejector
© Confederation of Indian Industry© Confederation of Indian Industry
vMain steam utilised as auxiliary steam
v From the turbine characteristic curve – Power
generation potential for 1 ton/hr of steam -250 units
v Install vacuum pump in lieu of steam ejector
v Vacuum pump specification
ØPressure - 660 mmHg
ØCapacity - 0.3 m3/sec
v Estimated power consumption - 47 kW
Install vacuum pump in lieu of steam ejector
© Confederation of Indian Industry© Confederation of Indian Industry
v Temperature gain in ejector condensor - 10oC
v Increase in steam consumption in deaerator - 1 ton/hr
steam at 5.5 kg/cm2
v Reduction in power generation - 100 units/ton
v Net benefit - 100 kW
Install vacuum pump in lieu of steam ejector
Annual Saving - Rs 48.00 LakhsInvestment - Rs 15 Lakhs
Payback period - 4 Months
© Confederation of Indian Industry
5. Install Thermo compressor and recover flash steam from feed tank
v Condensate from digester – Collected in feed tank
v Heat balance of feed tank and estimation of flash steam quantity indicate
q Flash steam quantity is about 2.55 tons/hr
Flash Steam t o atomos phere
(Y) kg
Water in feed tank @ 0.3 kg/cm2
170 TPH
Condensate (1 – Y) kg
98 °C
Flash vessel
© Confederation of Indian Industry
Install Thermo compressor and recover flash steam from feed tank
Motive Steam @ 33 kg/cm2(abs)Temp – 390 oCFlow – 1.5 tons/hr (approx)
LP Steam @ 0.1 kg/cm2(abs)Temp – 100oCFlow – 2.0 tons/hr
Discharge Steam @ 2.5 kg/cm2(abs)Flow – 3.5 tons/hr
© Confederation of Indian Industry
Install Thermo compressor and recover flash steam from feed tank
v Good potent ial to recover the flash steam
v Best option - Installing thermo compressor and inject ing
back to low pressure header
Annual saving - Rs 28.16 LakhsInvestment - Rs 30.00 LakhsPayback - 13 Months
© Confederation of Indian Industry
To sum up…
vTremendous potential for Energy Saving in
Boilers & Steam systems
vBecome a world class energy efficient unit
ØImplement the latest technologies
ØLearning the best practices from other sector /
industries
© Confederation of Indian Industry
Contact…
S KarthikeyanSenior Counsellor
CII-Sohrabji Godrej Green Business Centre
Confederation of Indian IndustrySouthern Regional Headquarters
98/1 Velacherry Main Road, GuindyChennai – 600 032
Email : s.karthikeyan@cii.inMobile : +91 98400 02983
Website : www.greenbusinesscentre.com / www.cii.in
Thank You…