SITE

Sandborn, Indiana

PROBLEM

Thermal Coal Dryers burn medium sulfur coal to produce heat and drive off the moisture from the coal prior to shipment. One major coal supplier decided, for economic reasons, to move an existing Thermal Dryer with the associated particulate scrubber to a new site in Indiana. To obtain a permit to construct this dryer, the State of Indiana required that both particulate and SO₂ emissions be controlled. This meant replacing or modifying the existing scrubber.

solution

Emtrol received the contract to design and supply a complete system for removal of SO₂ from the particulate scrubber exhaust. After careful engineering analysis, it was decided to modify the existing scrubber instead of replacing it. The modification consisted of a specially designed tray absorber stage utilizing caustic soda (NaOH) as the scrubbing reagent. The absorber was designed as a flanged module to be inserted within the existing scrubber entrainment separator. In addition, Emtrol designed and supplied all ancillary components such as recycle pumps, piping, caustic storage and feed system and all required instruments and controls.

The Emtrol Tray Scrubber design was selected over packed absorbers because of the possibility that carryover of coal fines would foul a packed design. Also, scaling problems were anticipated due to the high amount of calcium in the water supply in this location. Design criteria for this system were as follows:

result

The Emtrol W60 has exceeded the required emission limits for both particulate and SO₂ and has proven reliable and efficient. Emtrol's expertise in scrubbing technology, corrosion resistant materials and system design has proven valuable in this and many similar applications.