Significant Energy Savings with VSDs on Plant Feed Pumps
PLANT FEED PUMPS
Surface applications at most mining sites make use of pumps feeding water into the plant. In a recently installed application, Energy Drive identified two water feed pumps which provide water to the storage dam suppling a wash plant. The pumps are belt driven by two 132 kW motors at 415 V.
Due to the varying plant water requirements, the pumps are sized to deliver adequate water to meet the highest demand. As a result, the storage dam overflows during periods where less water is required; therefore, the site expends energy for no process gain.
The site team recognised this energy saving opportunity, and elected to partner with Energy Drive to deliver a solution. Energy Drive’s unique zero-capex “energy as a service” approach allowed the client to focus on production with the confidence that the project would be delivered effectively. Going forward Energy Drive will monitor and fully maintain the installation providing guaranteed uptime and response.
During the assessment phase Energy Drive collaborated with the site engineering team to analyse the operation of the water feed pumps. A proposal that detailed a capex-free energy saving solution was developed and approved
by both parties.
In June of 2021, Energy Drive installed a tailored variable speed drive solution on the existing water feed pumps. This allowed the site to make use of an ultrasonic level detector to control the storage dam level to a setpoint that suited them. This solution allowed the site to run the pumps at much lower frequencies, only providing the water necessary to keep the dam level at the stipulated setpoint.
The system has been operating under Energy Drive control since 01 June 2021 and is forecast to produce 1 598 166 kWh in savings over the contract period. The Energy Drive team will continue to maintain contact with engineers and operators on site to further understand and optimise the system on an ongoing basis. In addition to energy saving, the system will also lengthen the service intervals on the motors, pumps and pulley system due to a decrease in the electrical and mechanical load.