An energy efficient approach for flow control of parallel blowers

Iron and Steel Industries are one of the largest consumers of energy. The cost of energy accounts for nearly one third of production cost of the steel. In this paper operating conditions of blowers are investigated and an energy efficient approach to finding optimized speeds of VFD equipped parallel blowers for further energy saving is developed based on pattern search algorithm. This approach can find each turbo machine's optimized speed for any desired total flow. The minimum energy consumption is the goal of this approach. We have considered effect of motor and VFD efficiency variation on system's optimized operating point. Furthermore mechanical rules governing parallel blower's appropriate operation are considered carefully in goal and constraints functions of pattern search algorithm. Unmatched blowers are rarely used for parallel operation so we neglected unmatched parallel blowers configuration. As a case study the amount of energy saving gained by applying our suggested approach to the parallel blowers of steel making plant of Hormozgan steel complex is calculated.