Grindex Pumps in Commonwealth Edison Plants
Application:
Removal of bottom ash from pump pit
Commonwealth
Edison, the supplier of electricity to the metropolitan area of Chicago, IL is
using approximately 15 Grindex dewatering and sludge pumps. The pumps are used
to remove bottom ash from a pump pit.
Bottom ash is
the residual coal that does not burn in the process of heating the water to turn
the turbines. The presence of this material makes the system very inefficient,
the bottom ash must be disposed of by blowing it down into a sump pit along with
water and some other chemicals. The mixture of the bottom ash, water and
chemicals makes for a heavy abrasive sludge that most pumps will not handle. The
application called for a Semi sludge pump. However, to prevent the solids
settling down in the bottom of the pit. when the pump is not running a water
wand with a solenoid valve in the bottom of the pit sends streams of water into
the pit, agitating the solids to keep them in suspension. Once in suspension the
Semi pump handles all the bottom ash along with the water that accumulates in
the sump pit. This also prevents maintenance crews from having to crawl down
into the sump pit to clean out the messy bottom ash.