Optimisation Of Inlet Guide Vanes (IGV) Low Pressure Compressed Air Blower Number 5 Process Description Number 5 blower at Mines Power Station (MPS) is an Ingersoll Rand centrifugal blower capable of delivering 17 m 3 /s of compressed air at 140 kPa. It supplies low pressure compressed air to the various process plants at MIM site. Process demand for low pressure compressed air varies during the day which necessitates blower operation under unloaded condition or lower duty for significant periods of time which is an inefficient operation from energy consumption perspective. Copper Smelter recognised the need for optimisation of blower operation to reduce energy consumption.
As part of EEO cycle 2006-2011, a workshop was held to identify energy efficiency opportunities for Copper Smelter. Workshop was attended by technical personnel from Copper Smelter who raised the energy wastage issue related to Number 5 blower operation. Preliminary investigations indicated that the opportunity had energy savings potential and is worth pursuing. Copper Smelter included this opportunity as part of Continuous Improvement (CI) investigation after carrying out initial assessment process.
6 Energy savings by IGV optimisation One of the ideas recorded during the EEO workshop was to save blower energy consumption during unloaded and partially loaded operating condition by the optimisation of IGV. IGV’s perform the function of controlling blower output by opening and shutting of the vanes. Operational trials were conducted to observe the effect of vanes opening on power consumption. Optimum settings under different operating conditions were determined. All trials were conducted by internal resources.
7 Steps Followed Following steps were followed from identification of idea to implementation: Identification of idea Internal discussions and preliminary investigations Supervisor’s involvement CI process assessment and evaluation Operational trials Determination of cost benefits and resources requirements Implementation Verification of benefits.
10 Results of test trials Unloaded Energy Consumption KW Before Modification1797 After Modification1662 Power Reduction kW135
11 Energy savings and CO2 reductions * Energy savings and cost savings are function of process demands. Power reduction135 kWh Energy saved per annum*1080 MWH Cost savings*~$100,000/year Reduction in CO 2 615 tonnes/year Energy savings10.8TJ/year
12 Typical monthly cost savings MonthsCost savings February 2010$9,413 May 2010$11,609 January 2011$4,008 April 2011$5,970
13 Lessons learned Involvement of site technical personnel is critical in the identification of energy efficiency opportunities Support of middle management encourages the involvement of operational personnel and results in effective outcomes An EEO assessment is very beneficial in the understanding of entire process and operational and maintenance issues There are many opportunities for realising energy savings and cost benefits without the need for large capital expenditure Xstrata’s CI process is complimentary to EEO assessment, particularly Key Elements 4 and 5.