LAFARGE BATH
Lafarge North America is the largest diversified supplier of construction materials in the United States and Canada. Their products are used in residential, commercial, and public works construction projects across North America.
Located on the North Shore of Lake Ontario, Lafarge’s Bath Cement Plant produces 1.1 million tonnes of cement each year.
The Challenge
In 2012, Lafarge’s Bath plant began preparations for two environmentally-beneficial projects. Among the projects’ bottlenecks were two identical kiln ID fans with radial-tip-blade impellers and variable speed drives. The initial assessment indicated that the fans’ efficiencies were extremely low and that future performance requirements could not be met. Lafarge contacted AirStream to investigate upgrading the fans’ performance and reducing their power consumption.
The Solution
AirStream conducted fan performance assessments in January of 2013, which indicated that fan efficiency was only 54.2 percent for a two fan flow of 488,025m3/hr. We proposed fan upgrades that guaranteed an increase in efficiency to 87 percent. The two fan drive-input power use would be lower by 287 kW at test flow. Additionally, the new rotors would attain much more pressure and a flow of 666,000m3/hr with future 1250-hp motors. For present operation up to 596,000m3/hr, the existing 800-hp motors would be used.
The upgrade consisted of two new backward curved-blade rotors and was engineered to minimize equipment and installation costs by reusing the existing fan housings, dampers, couplings, and bearings. Although the rotors were 26 percent larger than the existing rotors, only modest fan housing modifications were needed.
The Results
In June 2014, AirStream carried out verification tests to ensure that the fans were providing guaranteed efficiency and performance. Our tests indicated that following the fan rotor upgrades, efficiency was increased from 54.2 percent to 87 percent. The 32.8 percent increase in efficiency was especially important because at time, the Ontario Power Authority (OPA) offered financial incentives to reduce power consumption. In addition to the incentives received, their increase in efficiency ultimately led to reduced operating costs.
