Energy efficiency opportunities resulting from splitting a compressed air ring

The purpose of this study was to implement an energy efficient strategy on a compressed air ring of a South African gold mine. The basis of the strategy was to identify the high- and low pressure end users and, if possible, divide the single compressed air system into two separate systems that would receive compressed air at different but correct operating pressures. Energy savings could then be expected because of reduced pipe friction losses as a result of lower operating pressures. Air leaks, through holes in the pipeline and other possible leak prone areas would also be reduced because of the lower pipeline operating pressure. It was possible to divide this compressed air ring into high- and low pressure sections. The reduced air flow in the low pressure section of the ring resulted in less air being lost through air leaks. Furthermore, smaller pressure losses were experienced over the length of the line as a result of reduced line friction. The resulting energy savings achieved was a direct result of the compressors being able to supply lower pressure compressed air to selected parts of the compressed air ring. High pressure compressed air was still maintained on the high pressure side and each compressed air system received compressed air at the correct pressure to maintain operational production as before.