Cement Plant General

In cement plants generic measures like preventive maintenance, use of efficient motors, efficient and variable speed drives, proper insulation, optimization of compressor and lighthing systems can help reduce energy consumption. 

Cement Plant GeneralTechnologies & Measures

Technology or MeasureEnergy Savings PotentialCO2 Emission Reduction Potential Based on LiteratureCostsDevelopment Status
Preventive Maintenance

Reduction of up to 5 kWh/t-clinker through various preventative maintenance and process control measures was reported  Typical savings are around 3 kWh/t clinker.

Start-up and implementation costs of preventive maintenance tend to be very low, often resulting in payback times of less than one year. 

Commercial
High efficiency motors & drives

Power savings may vary considerably between different plants, ranging from 3 to 8%. 

By retrofitting 13 motors with high efficiency ones a cement plant in Davenport, California, has saved 2.1 MWh of electricity annually.

For a 5000 tons per day plant, it is estimated that replacing all motors in plant fan systems with high-efficiency motors costs US $0.22 per annual ton of cement capacity. 

The cement plant in Davenport, California, has reduced its annual energy and maintenance costs by US $168 000 and US $30 000 annually. The implementation costs amounted to US $ 134 000 (including a rebate from the local utility company) giving a payback time of around 8 months.  

Commercial
Variable Speed Drives

The savings VSDs provide can vary between 7 to 60% depending on the flow pattern and loads. (ECRA, 2009)

Other sources estimate that the potential savings are 15% for 44% of the installed power, or roughly equivalent to 8 kWh/t cement (LBNL, 2008)

In a Canadian plant, replacing the kiln ID fans with VSDs saved 6 kWh/t.

The specific costs depend strongly on the size of the system. For systems over 300 kW the costs are estimated to be 70 €/kW (75 US$/kW) or less and for the range of 30-300 kW at 115-130 €/kW (120-140 US$/kW). Based on these, the specific costs for a modern cement plant was estimated to be roughly US $0.9 to 1.0/annual ton cement capacity.

VSDs for clinker cooler fans have a low payback, even when energy savings are the only reason for installing. 

Commercial
Compressed air system maintenance

Through more frequent filter chaning, a 2% reduction of annual energy consumption in compressed air systems can be realized. 

The payback for filter cleaning and maintaining drain traps is usually under 2 years.

Commercial
Reduced Leaks in Compressed Air Systems

A 20% reduction of annual energy consumption in compressed air systems is projected for fixing leaks.

Commercial
Compressor Controls

 

Sophisticated controls can provide up to 12% energy savings annually. 

Changing the compressor control from on/zero/off to a variable speed control can save up to 8% per year. 

Typical payback for start/stop controls is 1 to 2 years.

Commercial
Proper Selection of Compressed Air Dryer

A rule of thumb is that desiccant dryers consume 7 to 14% of the total energy of the compressor, whereas refrigerated dryers consume 1 to 2% as much energy as the compressor

Commercial
Reducing Compressor Inlet Air Temperature

As a rule of thumb, each 3 °C will save 1% compressor energy use.

Importing fresh air can have paybacks of 2 to 5 years.

Commercial
Proper Sizing of Pipe Diamaters

Increasing pipe diameter typically reduces annual energy consumption by 3%. 

Commercial
Lighting ControlsNot availableNot availablePayback of lighting control systems is generally less than 2 years.Commercial
Replace T-12 Tubes by T-8 TubesEfficacy of lighting can be doubled. Not availableNot availableCommercial
Replacing Mercury LightsMetal halide lamps can replace mercury or fluorescent lamps with an energy savings of 50%. High pressure sodium lamps offer energy savings of 50 to 60% compared to mercury lamps.Not availableNot availableCommercial
Replacing Metal Halide HIDHigh-intensity fluorescent systems yield 50% electricity savings over standard metal halide HID.Commercial
Replace Magnetic Ballasts with Electronic BallastsElectronic ballasts save 12-25 percent more power as compared to magnetic ballasts. Not availableNot availableCommercial