An assessment of energy cost saving a cement grinding plant case study
Abstract
The production of cement is an energy-intensive process. The cost of energy as part
of the total production costs in the cement industry is significant and warrants
attention to energy efficiency to improve the bottom line. As the cost of energy
continues to rise, Bamburi Cement Limited has experienced higher cost of energy
especially over the last five years. In 2008, the fuel cost had risen by 361% since
2003 and the cost of electricity had increased by 226% in the same period.
The Nairobi Grinding Plant (NGP) of Bamburi Cement had a maximum electricity
demand range of 7.7 MVA to 7.9MVA in period 2007 to 2008. The plant operates on
a 24-hour basis with an equipment maintenance strategy and schedule in place. The
plant has two grinding mills each using a 2800kW motor, and with their associated
auxiliaries they consume about 90% of the plant’s electrical energy. The balance of
the energy is consumed by fans, electric motors, and compressors and lighting.
Electrical sub-metering is done for mills, mill auxiliaries, the separators, raw
materials section, packing plant, general utilities and group information technology
(IT) infrastructure.
The grinding plant’s average monthly electricity consumption was 4,182 MWh in
2007 and 4,264 MWh in 2008 with recorded intensities of 47 kWh/ton and 41
kWh/ton respectively. In 2007 and 2008, electrical intensity varied up to 36 kWh/ton
at high production rates of over 120,000 tons per month while it went up to
48kWh/ton at low production below 80,000 tons per month. The plant target is an
intensity of 40 kWh/ton for an average production of 100,000 tons per month.
Citation
Master of Science Energy ManagementSponsorhip
University of NairobiPublisher
School of engineering department of geospacial and space technology