Abstract

The preheater induced draft (ID) fan, the raw mill fan, and the baghouse ID fan are all major consumers of electrical power in a cement plant. Given such a fierce, competitive marketplace, it is wise, if not imperative, to evaluate these fans and their draft systems to optimize operating efficiency to save input horsepower and, in turn, consumed electrical power. These power-reducing upgrades can also substantially reduce the emissions and the overall carbon footprint of the process. An opportunity arose at a cement plant while the rotor of one of the preheater ID fans was becoming a maintenance issue and reaching the end of its operational life. The foresight of plant personnel reasoned that if it had to be replaced, an upgrade of the rotor should be considered, particularly considering the fact that their electricity provider was offering rebates for power savings. This paper presents a case history including all the challenges along the way to replace the original, antiquated radial blade rotor design with a more efficient, properly selected, and modern backward curved design. The result of this commitment to modernization dramatically lowered the input electrical requirements creating considerable operational savings with an attractive rate on the return of investment.

Introduction

In an industrial process such as cement production, one of the larger parasitic loads is from the horsepower requirements, resulting in electrical power consumption of the mechanical draft fans. Fans that are improperly selected and designed tend to be extremely inefficient, causing increased operational expense, unnecessary carbon emission, continual maintenance issues, and limitations on production. In today’s competitive market, it is wise, if not imperative, to examine these fans and the associated draft systems to evaluate optimizing efficiencies and what the return on investment of these power conservation upgrades would yield. These power-reducing upgrades can also substantially reduce emissions and the overall carbon footprint. Within this competitive market, upgrading your fans can be the factor that not only prevents maintenance issues, but essentially provides more production success while eliminating, or at the least minimizing, any forced outages.