Weyerhaeuser's Paper Mill in Albany, Oregon has been experiencing
frequent ring formation in the #3 rotary lime kiln. Rings form when lime mud
(CaCO₃) or product lime (CaO) particles adheres to the walls of the lime kiln and
become resistant to the abrasive action of the sliding motion of product lime
particles (Notidis, 1994). Ring formation has resulted in frequent shut downs to
remove (blast) the rings and caused a significant loss of productivity and revenue to
the company. A careful analysis of the production process in the mill revealed that
concentration of sodium was high and that of sulfur low in the lime mud.
The high sodium was due to the low sulfur input to the kiln resulting in high
sodium to sulfur ratio. The use of natural gas as a fuel source in the kiln partly
causes low sulfur levels in the mud.
This study examines the effects of burning emulsified sulfur in the #3
rotary lime kiln to reduce sodium enrichment in the solids, and examine its effect
on kiln operation and SO₂ emissions from the #3 rotary lime kiln. A four day trial
of burning emulsified sulfur to reduce sodium concentration in the #3 rotary lime
kiln was planned. Tote bins of 70% solution of emulsified sulfur was fed into the #3 rotary lime kiln. The sulfur feed was controlled to ensure an excess of sulfur by
observing the SO₂ concentration in the kiln stack and maintaining a concentration
above 100 ppm corrected to 10% oxygen.
The results show that while burning emulsified sulfur had no significant
effect on kiln operation, it resulted in a high reduction of sodium in the dust caught
in the electrostatic precipitator and an increase SO₂ emission from the stack. The
reduction of sodium in the dust was 50%, which is an enrichment factor of 2.
Although lime can effectively remove SO₂, the removal efficiency decreased from
96.0% to 73.0% when emulsified sulfur was burned in the #3 rotary lime kiln.
The results of this trial are promising, since it demonstrates that burning
emulsified sulfur significantly lowers the sodium enrichment in the kiln. The
reduced levels of sodium can potentially lead to a reduction in ring formation in the
#3 rotary lime kiln in the Albany Paper Mill. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/30191 |
| Date | 08 January 2004 |
| Creators | Djokotoe, Diana |
| Contributors | Rochefort, Willie E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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