Energy-efficient operation of pump drives in a cement plant

Electric motors consume a large share of electricity in cement industries. Traditionally, most of the motor applications use variable frequency drive to save electricity, but they do not optimally minimize power consumption always. Pumps and fans are the applications where significant energy savings can be obtained at partial load by implementing optimal flux control. The present work identifies 10 large-size pump motors of an integrated cement manufacturing unit and proposes optimal flux control in a novel way during their operation. The proposed method eliminates run-time optimal flux computations, perturbations, and convergence issues as compared to conventional techniques along with excellent dynamic response. Significant savings of $0.237 million in annual energy cost, 3261.6 tons of combusted coal, and reduction of 3359.5 tons green-house gas emissions in a year are estimated at an average 90% loading condition. The estimated energy saving will be in line with "good practice" benchmarks for industries.