There Reduction of alkali loss in an ash leaching system
Source abstract
Abstract
There are many points in a kraft mill where the alkaline compounds are purged from the process. Several effluents, solid waste, and air emissions contain alkali, which leads to the necessity of chemical makeups to maintain the liquor balance. The main loss of alkali at the Veracel mill is present in the wastewater from the recovery boiler; more precisely, it is from the ash leaching system, which represents 80% of the total losses. To minimize the alkaline losses while keeping the chloride level in the recovery cycle under control, a project was developed at Veracel. Key actions were taken by adjusting the control loops of the ash leaching system, mainly on the slurry density and purge control. These adjustments led to a decrease in alkali losses and to an increase of treated ash, and kept the chloride level of the recovery boiler dust at 2.6%.
Source: crossref · Quality: baseline
Research context
OpenAlex topics: Advanced Control Systems Optimization · Mineral Processing and Grinding
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References (5)
Show source-provided references
1. Tran, H.N., in Kraft Recovery Boilers (T.N. Adams, Ed.), TAPPI Press, Atlanta, GA, USA, 1997, Chap. 9.
2. Johansson, U., “Different methods for the purge of chlorides and potassium from electrostatic precipitator dust
3. in the kraft mill,” M.Sc. thesis, Lund Institute of Technology, Lund, Sweden, 2005.
4. Gonçalves, C., Tran, H., and Shenassa, R., “Factors affecting chloride and potassium removal efficiency of a recovery boiler pre-cipitator ash treament system,” Int. Chem. Recovery Conf., PAPTAC/TAPPI, Montreal/Atlanta, 2007.
5. Eaton, A.D., Clesceri, L.S., Greenberg, A.E., et al., Eds., Standard Methods for the Examination of Water and Wastewater, 20th edn., American Public Health Association, Washington, DC, 1998, pp.3-98, 4-66.