Download WHAT IS ENERGY CONSERVATION

CONSERVATION OF ENERGY IN
SUGAR INDUSTRIES
National Sugar Institute, Kanpur
AREAS OF HIGH POWER
CONSUMPTION
•Cane preparation
•Mills
•Condensing and Cooling
•Centrifugal
AREAS OF ENERGY CONSERVATION
Area
Existing plant &
process
Energy efficient
plant & process
Energy production
Boiler/Turbine
efficient operation
High pressure
boiler/condensing
turbine
Energy consumption Use of VFD,
Helical gears, Anti
friction bearings,
Use of flashes etc.
DC/AC thyristor
controlled motors,
continuous pan,
direct contact
heaters etc.
ENERGY CONSERVATION POTENTIAL IN
SUGAR INDUSTRY
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Indian sugar industry is highly energy-intensive
Energy efficiency is well below that of other
industrialized countries
Energy conservation measures shall lead to
reduction in cost of production
Thus to make Indian sugar Industry more
competitive globally
The total energy conservation potential is 25% of
total energy consumption
POTENTIAL FOR REDUCTION IN STEAM
CONSUMPTION
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Reduction in direct steam leakages
Insulation of bare pipes flanges and valves etc. to reduce surface
temperature 55oC
Reduction in redundant steam pipelines
Pressure control and syrup Brix control in the evaporator section
Adequate changes in steam and juice piping to ensure juice
heating from different bodies of evaporator
Application of continuous crystallizers for A B & C massecuites
and continuous centrifugals for B & C curing, high gravity/high
capacity batch centrifugals for a curing etc.
Improved instrumentation and control for pressure and
temperature of exhaust steam required for process
Rationalization of operations of minimize fluctuations in steam
demand
MAJOR ENERGY EFFICIENCY IMPROVEMENT
AREAS IN SUGAR INDUSTRY
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CANE MILLING
STEAM GENERATION
POWER GENERATION
SUGAR PROCESSING
LIGHTING SYSTEM
CO-GENERATION
CANE MILLING
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Use of antifriction bearings at head and tail shafts of
cane carrier and mill transmission gears
Use of HT motors for cane cutter and fibrizer
Use of VFD at cane carriers, rake carriers
Use of high efficiency planetary gear drive
Use of hydraulic motor and AC VFD for mill drive
Use of belt conveyor in place of chain and slat
conveyor
Optimization of imbibition percent
Adoption of complete mill house automation
Proper planning to decrease stoppages/reduce crushing
situation due to shortage of cane
STEAM GENERATION
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By adopting high efficiency boilers, steam generation to fuel
ratio can be increased
Reduction in specific steam consumption by adopting high
pressure and high temperature boilers
Recovery of heat from flue gas by using bagasse dryer
Use of VFD for ID and FD fans
Use of HP/LP heater for boiler feed water to increase cycle
efficiency
Recovery of heat from blowdown
The amount of blowdown should be minimized
Add waste heat recovery unit to blowdown for flash steam
generation
Adoption of complete combustion
Control on excess air supply
EFFICIENT BOILER OPERATION
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It may means to reduce the heat losses to minimum
so as to increase the efficiency of boiler
HEAT LOSSES
Heat loss in flue gas
Heat loss due to moisture in bagasse
Heat loss due to Hydrogen present in bagasse
Heat loss due to blowdown
Heat loss due to radiation/convection
Heat loss due to bad combustion of Carbon
Losses in unburned solids
REDUCE STACK TEMPERATURE
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Stack temperature greater than 170 deg. C
indicates potential for recovery of waste heat
Use of bagasse dryer
22deg.C reduction in flue gas temperature
increase boiler efficiency by 1%
COMBUSTION AIR HEATING
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The rise in combustion air temperature
by 20deg.C will improve thermal
efficiency by 1%
INCOMPLETE COMBUSTION
IT MAY BE DUE TO FOLLOWING
REASONS
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Shortage of excess air
Excess of fuel supply
Poor distribution of fuel
CONTROL ON EXCESS AIR
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The optimum excess air level varies with
furnace design, type of fuel and process
variable
Excess air % theoretical air should not
exceed to 35%
For every 1% reduction in excess air, 0.6%
rise in boiler efficiency
RADIATION AND CONVECTION HEAT LOSS
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The surfaces lose heat to the
surroundings depending on surface area
and the difference in temperature
between the surface and surroundings
With modern design boiler this loss may
represent only 1.5% on GCV
BLOWDOWN HEAT LOSS
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This loss varies between 1% to 6% and depends
on number of factors
Total dissolved solids (TDS) allowable in boiler
water
Quality of makeup water
Amount of uncontaminated condensate return
Boiler load variations
Correct checking and maintenance of feed water
and boiler water quality, maximising condensate
return and smoothing load swings will minimise
the loss
BLOWDOWN HEAT RECOVERY
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Blowdown of boilers to reduce sludge and solids
contents allows heat to go down the drain
The amount of blowdown should be minimised by
allowing a good water treatment programme
Installation of a heat recovery unit (heat
exchanger) in the blowdown line allows the waste
heat to be used in preheating make up and feed
water
AUTOMATIC BLOWDOWN CONTROL
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Uncontrolled continuous blowdown is
very wasteful
Automatic blowdown control can be
installed that sense and respond to
boiler water conductivity and pH
REDUCTION OF SCALING AND SOOT LOSSES
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Soot build up on tubes acts as an insulator against heat
transfer. Any such deposits should be removed on a
regular basis. Elevated stack temperature may indicate
excessive soot build up. Also same results will occur due
to scaling on the water side.
Stack temperature should be checked and recorded
regularly as an indicator of soot deposits.
Every millimeter thickness of soot coating increases the
stack temperature by about 55 deg.C
3mm of soot thickness can cause an increase in fuel
consumption by 2.5%
A 1mm thick scale on water side could increase fuel
consumption by 5 to 8%
SUGAR PROCESSING
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Optimization of evaporator design to minimize exhaust steam needs and
maximize vapor bleeding
Optimization of syrup Brix
Stepwise recovery of flash heat from the condensate of evaporator, juice
heaters and pans
Use of first condensate for wash water heating at centrifugals.
Recovery of waste heat from clarifier flash tank
Selective incorporation of direct contact heater
Use of continuous pans for massecuite boiling
Seed sugar melting by using syrup and very low temperature vapour in place
of exhaust steam and hot water
Use of efficient heat exchanger
Elimination of direct live steam bleeding in process
Adoption of process automation and controls
Discouraging production of bold grain
Use of low temperature vapour for pan washing
Heating of air by hot condensate at sugar dryer / hopper
Recovery of heat from non condensable gases
USE OF PLANETARY GEAR DRIVE
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Transmission efficiency is about 90%
Combined efficiency of conventional
worm and worm wheel with enclosed
worm gear box is hardly 40-50%
HELICAL GEAR DRIVE
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The efficiency of helical gear drive is
approx. 96-97%
The efficiency of worm gear box is
70-80%
LIGHTING SYSTEM
• Make maximum use of natural light (Use of
translucent sheets / more windows and opening)
• Switch off when not required
• Modify lighting layout to meet the need
• Provide lighting transformer to operate at reduced
Voltage
• Install energy efficient lamps, luminaries and controls
• Use of gas discharge lamps in place of incandescent
lamps
• Use of Compact Fluorescent lamps (CFL)
• Use of Metal Halide lamps in place
Mercury/Sodium lamps
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CO-GENERATION
• Sequential production of process heat
and electricity to export with same fuel
is termed as co-generation
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In sugar industry the co-generation is
of TOPPING CYCLE
TOPPING CYCLE
The steam generated is fed to the turbo
generator and extracted at desired
pressure for process work
BENEFIT OF CO-GENERATION
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The fuel, bagasse is renewable source of energy
The sugar industry generates additional power
with the bagasse which is used for generation of
steam to meet process requirements
Results in reduced emission levels and global
warming and is therefore environment friendly
Ensure fuel security
Co-generation project leads to reduction in
transmission losses considerably and thus helps in
stabilizing the grid voltage because of their
proximity to the load centres
ENERGY EFFICIENCY IMPROVEMENT
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The system upgradation in the entire sugar
manufacturing process for improved energy
efficiency goes for maximizing exportable power
from co-generation plant
Energy efficiency improvement and energy
conservation is of great importance for making the
co-generation project viable and sustainable in the
long run.
Implementing energy conservation measures in
respect of both steam and electricity will reduce
captive consumption and help to save additional
quantity of bagasse/electricity.
TURBINE COFIGURATIONS FOR COGENERATION
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Pure back pressure turbine
Single extraction back pressure turbine
Double extraction back
turbine
Pure condensing turbine
pressure
Single extraction condensing turbine
Double extraction condensing turbine
AREAS OF ENERGY CONSERVATION
Steam temperature at the turbine inlet,
Steam pressure at the
turbine inlet, Kg/cm
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62
63
100
440
4.25 4.00
3.90
3.86
460
4.03 3.82
3.80
3.76
470
3.98 3.79
3.70
3.60
480
3.94 3.75
3.68
3.57
490
3.90 3.72
3.60
3.50
510
3.80 3.65
3.55
3.35
RENEWABLE ENERGY
Renewable can create a significant impact in electric
power generation. Indian Renewable energy programme
is the largest and most extensive among the developing
country. Ministry of Non-conventional energy the nodal
Ministry of the Govt. is entrusted with responsibility of
policy making, planning, information and co-ordination
of various aspects of renewable energy. As per their draft
policy set up for the goal is to be achieved till 2012 an
addition of
10% share I.e. 12000 MW through
renewable.
RENEWABLE ENERGY SOURCES
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Co-generation from bagasse
Supplementary fuel such as cane
trashes, wood chips, rice husk and
other biomass material
Hydro-power
Wind power
Sea tides
Pelamis wave power