Lime Dosed Fume Scrubbing Plant
The three compartment fume scrubber used
screw conveyors to feed lime into the air stream to remove
acidic gases.
The existing control system had no sensors to determine if
the lime was feeding, or at what rate, with the result that
the scrubbing was often inefficient and on occasion the feeders
would flood and blind the filter bags.
The existing feeders were replaced with metering feeders mounted on loadcell
weighing assemblies. Differential pressure transducers were
installed to measure the pressure drop across the individual filter
compartments.
The addition of a Mitsubishi PLC and an
MMI package allowed precise control of the Lime dosing together
with improved diagnostics. The resultant savings in manpower
and downtime alone gave a one year payback and the improvement
in cleaning kept the plants emissions well within statutory
requirements.