LAFARGEHOLCIM HOLLY HILL
In October 2013, the cement plant in Holly Hill, South Carolina completed a successful upgrade of their Kiln ID fan rotor. AirStream conducted in-depth system testing according to AMCA standards to determine the actual system resistance and flow distribution characteristics. The new rotor was modeled in the existing fan housing to deliver and increased flow at continuous temperatures of 500⁰C (932⁰F). The high temperature fan capabilities enabled the plant to significantly decrease cooling water, natural gas and electrical power consumption, reducing their carbon footprint. The project was completed reusing the existing fan housing, motor, and coupling. Verification testing was conducted after commissioning, confirming the fan performance and efficiency improvements.
The Challenge
The existing Kiln ID Fan rotor was experiencing hard build up resulting in vibration, as well as wear to the centerplate. Additionally, the rotor’s design limited operation of the fan to 425⁰C requiring cooling of the gas upstream of the fan, and reheating the gas downstream of the fan. Efficiency was also identified to be in the mid-60% range.
The Solution
AirStream conducted site performance tests in accordance with AMCA publication 203-90 to verify the existing system resistance and operating conditions. AirStream chose field performance testing because it measures fan capacity in the actual operating environment, the system characteristics and system effects that affect fan efficiency and wear life.
Development of a custom high efficiency rotor capable of continuous operation at 500⁰C was carried out by AirStream engineers using special design techniques and advanced high-strength materials. The final design was given a detailed FEA to confirm all parameters.
The Results
The rotor was installed during the 2013 shutdown in the existing fan housing, reusing the existing motor. The follow up performance test conducted by AirStream and LafargeHolcim in May 2014 verified the fans design efficiency of 81%, and power savings of 335 kW.
In addition to the fan power savings, the operational project benefits also included:
- Reduced down time due to elimination of the hard slate-like buildup on the impeller blades;
- AirStream’s unique aerodynamic design has extended rotor wear life;
- Increased capacity in accordance with plant’s operating requirements;
- Significantly reduced plant cooling water use, saving 8176.5 litres/hour;
- Reduction in thermal energy consumption of approximately 64 MJ/t raw meal, equal to 4,600 tonnes/year of natural gas; and
- Virtually eliminated the need for the 600kW raw mill hot gas booster fan and other associated infrastructure.
