An emission control system was being redesigned by Orbital Engineering, Inc. to incorporate Variable Frequency Drive (VFD) fan systems to improve system efficiency in light of rising process demands.
The existing design consisted of two 7,500 hp (5,600 kW) damper-controlled fans, two baghouses, and two spray dryer absorbers. When the system was constructed, one of these flow paths was intended to serve as a standby system, but increased process demands led to both subsystems being used concurrently and fully utilizing maximum installed capacity at times.
