To produce paper, the pulp wood is placed in a digester to dissolve the cellulose and produce wood fibers. The by-product of this process, black liquor, is sprayed into a recovery boiler and burned, producing green liquor in a bed combustion unit, where the temperature has to be maintained at approximately 1037°C (1900°F) to keep it burning. If the liquor is too wet, it will cause a “black-out” condition. If there is a lack of combustible material, then a starving condition occurs.
A sensor with a wide temperature range is required to monitor gas temperatures in the boiler tube area to insure they are hot enough to prevent the fly ash from building up on the water tubes.
The temperature of the green liquor and other chemicals in a rotary kiln is heated to about 1150°C (2100°F) and monitoring of the kiln temperature for hotspots or excessive wear of the refractory is important for quality and maintenance.
- Control black liquor moisture affecting boiler flame consistency
- Reduce maintenance costs through flame temperature monitoring