It is estimated that sugar mill units could save around 1,900 MWh of electricity and 5,080 GJ of thermal energy. By implementing energy efficiency the sector could achieve monetary savings of about 210 Lakh Nepalese Rupees annually. In total food sector could save energy costs of around 78 Crore NPR by going efficient (GIZ/NEEP, 2012).
| Sector | Electrical MWH | Thermal GJ | Money Npr |
|---|---|---|---|
| Cement | 1,488,829,349 | ||
| Clinker-based | 45,854 | 383,938,427 | |
| Limestone-based | 35,390 | 1,598,359 | 1,104,890,923 |
| Pulp & Paper | 919 | 136,848 | 33,663,972 |
| Food & Beverage | 783,680,733 | ||
| Beverage | 23,075 | 177,635 | 430,210,534 |
| Biscuit | 1,551 | 12,835 | 18,988,796 |
| Dairy | 7,584 | 192,145 | 257,647,474 |
| Noodle | 478 | 52,577 | 15,298,110 |
| Sugar | 1,900 | 5,080 | 21,020,412 |
| Vegetable Oil & Ghee | 1,911 | 124,337 | 40,515,407 |
| Metal | 5,522 | 202,695 | 281,870,090 |
| Soap & Chemical | 1,210 | 149,334 | 42,087,972 |
| Hotel | 29,445 | 97,056 | 360,432,716 |
| Brick | 3,374,780,735 | ||
| FC-BTK | 0 | 5,329,804 | 3,374,019,929 |
| VSBK | 0 | 1,214 | 760,806 |
| Cold Storage | 1,838 | 13,191,798 | |
| Total | 156,676 | 8,079,920 | 6,378,537,366 |
Moreover, by implementing the concept of co-generation based on its by-product bagasse , sugar mills in Nepal could generate electricity of around 70 MW capacity. They could feed electricity into the grid during dry season and, thus, contribute to mitigate load shedding.
Experience from the past have identified many options for improving energy efficiency in sugar industries that are highly profitable, most of them with payback periods of investment of less than 1 year.
Table 2: Energy saving options for sugar mills and payback period of investment (Danida/ESPS, 2005)| Options | Payback of Investment |
|---|---|
| Utilization of exhaust steam for sugar drier and sugar melter | 6 month |
| Installation of conial jet nozzles for mist cooling system | 2 years |
| Installation of an extensive vapour bleeding system at the evaporators | 1.5 years |
| Improvement of boiler combustion efficiency by regular monitoring and adjustment of air to fuel ratio | 1 year |
| Insulation of bare steam pipes, valves & flanges and hot water tanks | 1 year |
| Installation of commercial co-generation plant | 3-5 years |
Energy Saving Tips
Huge saving opportunities in sugar mills can be achieved in the following areas:
- Install lower size pump for weighted juice pump/Install VFD for weighed juice pump
- Install correct size pump for crusher
- Install correct size pump for imbibition water pump
- Install lower head pump with VFD for raw juice pump
- Install right size pump for imbibition water pumping
- Install Variable Frequency Drive for Imbibition Water Pump
- Install variable frequency drive(VFD) for cane carrier drives
- Install VFD for weighed juice pump
- Install DC drives/hydraulic for mill drives & shredder
- Install electronic mass flow meters for all three mills and avoid use of weighed juice transfer pump.
- Utilize L P steam for sugar dryer and sugar melting
- Avoid condensate water pumps at juice heaters and evaporators
- Commission load/unload mechanism for sulphur air compressors
- Improve flash steam utilization for S K condensate and quad-1
- Improve sealing of the stand-by blower, avoid damper control and reduce impeller size of the sugar drier blower
- Install lower size pump for clarified pumping/install VFD for clarified juice pump
- Install lower size pump for sulphite juice tank/install VFD for sulphite juice pump
- Install right pump for filter condenser water pumping
- Install rotary blower in place of Compressor for supplying air to syrup sulphur burner
- Install Variable Frequency Drive for super heated wash water pump
- Install VFD/small size pump/lower size impeller for mill IV juice transfer pump
- Optimize operation of spray pump
- Provide VFD for booster vacuum pump of vacuum pans (1-12)
- Provide VFD for rotary blowers of sulphur burner
- Segregate high vacuum and low vacuum requirements of Oliver filter
- Segregate spray water and jet water and use cold water only for spray
- Install lower head pump with VFD for raw juice pump
- Install right size pump for imbibition water pumping
- Install Variable Frequency Drive for Imbibition Water Pump
- Install variable frequency drive(VFD) for cane carrier drives
- Install VFD for weighed juice pump
- Install DC drives/hydraulic for mill drives & shredder
- Install electronic mass flow meters for all three mills and avoid use of weighed juice transfer pump.
- Arrest air infiltration in boilers
- Arrest identified steam leaks and improve the working of steam traps in identified areas
- Improve combustion efficiency of all the boilers
- Improve insulation in identified areas
- Rationalize condensate collection system
- Reduce RPM of power plant air compressor
- Use exhaust steam for deaerator water heating
- Convert identified MP steam users to LP steam users
- Install a flash vessel to recover the flash from the boiler continuous blow down & HP steam header traps drain and connect to exhaust header
- Install correct size pump for the condensate transfer pump
- Install L P steam heater in delivery of boiler feed water pump
- Install steam jet ejectors in place of vacuum pumps for vacuum filters
- Install thermo compressors with 150 psi steam for compressing 8 psi and 12 psi exhaust vapors to 16 psi
- Install variable fluid coupling for boiler ID fans
- Install Variable Frequency Drive for Auxiliary Cooling Water (ACW) pump
- Install Variable Frequency Drive for Condenser Water pump
- Install Variable Frequency Drive for SA & PS fans and operate in open loop control
- Install VFD for Boiler feed water pump
- Optimize capacity of boiler house compressor
- Replace identified fans with correct size high efficiency fans
- Commission de-aerator and utilize L P steam for heating condensate water in de-aerator
- Install heat exchanger to preheat boiler feed water
- Increase the temperature of fermented wash from 83 degree C to 90 Degree C by installing additional plates
- Install additional standby PHE for fermented wash heating
- Install lower head pump for fomenter circulation pump
- Install steam ejector and utilize LP steam for distilleries
- Convert delta to permanent star connection for the identified lightly loaded motors
- Install automatic star - delta - star converter in the identified lightly loaded motors
- Optimize the plant operating frequency, if operating in island mode
- Optimize the plant operating voltage
- Improve the P.F of the Identified feeders and reduce the cable loss
- Install automatic slip ring controller for the cane leveler
- Install soft starter cum energy saver at the lightly loaded motors
- Replace filament lamps installed in panel on/off indications with energy efficient led lamps
- Replace identified faulty capacitor banks
- Install lower size pump for weighted juice pump/Install VFD for weighed juice pump
- Install correct size pump for crusher
- Install correct size pump for imbibition water pump
- Install lower head pump with VFD for raw juice pump
- Install right size pump for imbibition water pumping
- Install Variable Frequency Drive for Imbibition Water Pump
- Install variable frequency drive(VFD) for cane carrier drives
- Install VFD for weighed juice pump
- Install DC drives/hydraulic for mill drives & shredder
- Install electronic mass flow meters for all three mills and avoid use of weighed juice transfer pump.
- Convert delta to permanent star connection for the identified lightly loaded motors
- Install automatic star - delta - star converter in the identified lightly loaded motors
- Optimize the plant operating frequency, if operating in island mode
- Optimize the plant operating voltage
- Improve the P.F of the Identified feeders and reduce the cable loss
- Install automatic slip ring controller for the cane leveler
- Install soft starter cum energy saver at the lightly loaded motors
- Replace filament lamps installed in panel on/off indications with energy efficient led lamps
- Replace identified faulty capacitor banks
- Install level based ON / OFF control for service water pumps
- Install LIC for service tank/Install correct size pump for service tank
- Install temperature cut-off switch for cooling tower fans
- Arrest compressed air leakages at packing section
- Convert ‘V’ belt to flat belt drive at the identified equipment
- Install auto drain valve for instrument air compressor
- Install correct size pumps for hot water pumping at cooling tower
- Install FRP blades for process Cooling Tower fans
- Install next lower size impeller for hot water process cooling tower pump
- Install Variable Frequency Drive for Cooling Tower fans
- Install Variable Frequency Drive for service water pump
- Provide cooling tower for identified equipments and stop use of fresh water
- Segregate the low vacuum and high vacuum of Oliver filter
References
- GIZ/NEEP, 2012: Baseline Study of Selected Sector Industries to assess the Potentials for more efficient use of energy.
- Danida/ESPS, 2005: Cleaner Production report of Sugar industry.
- Confederation of Indian Industry: Investors manual for Energy Efficiency.
Supported By
