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How to use total dissolved solids measurements to evaluate the performance of diffuser washers—A mill study, TAPPI Journal April 2020
ABSTRACT: Various types of pulp washing equipment are available. Each washing device has a unique mechanical construction, and the washing principle is often a combination of dilution, thickening, and displacement washing. In this work, the performance of the pressure diffuser washer is studied. In stepwise trials, the effect of the feed and discharge consistencies on the performance of the diffuser was studied. The effect of the downward velocity of the screen on the pressure diffuser’s washing efficiency was also studied. The measurement of total dissolved solids (TDS) by a process refractometer was used as a wash loss measurement unit and the refractometer’s results were used in the calculations of standardized Nordén efficiency (E10) values. The chemical oxygen demand (COD) and conductivity values were also measured and their results compared to the TDS results.The results indicated that feed consistency has a significant effect on the performance and effectiveness of the diffuser washers in the mill. It can also be stated that when the downward velocity of the screen is adjusted to too high a level, the washing efficiency of the pressure diffuser decreases. As a conclusion from the mill tests, it can be stated that even small process parameter changes can provide enhanced diffuser washing at the beginning of the washing line, which has a direct effect on the performance of post-oxygen washing.
Journal articles
Magazine articles
Mill experience of calcium carbonate scale formation in green liquor pipelines, TAPPI Journal August 2020
ABSTRACT: Experience of hard calcite (CaCO3) scale formation in green liquor pipelines at four kraft pulp mills was systematically investigated to determine if there is any correlation between the severity of the scaling problem at each mill and the design and operating conditions of its causticizing plant. The results show that the high degree of supersaturation of calcium ions (Ca2+) in the liquor is the main contributing factor. Mills that operate at a lower green liquor total titratable alkali (TTA), higher causticity, and a larger liquor temperature drop are more likely to produce a green liquor that is supersaturated with Ca2+, and thus experience more severe scaling problems. In order to minimize CaCO3 scaling, the green liquor handling equipment should be operated as steady as possible to avoid conditions that allow Ca2+ to be supersaturated. The strategies include minimizing variations in liquor TTA, insulating the green liquor pipelines to reduce temperature gradients, and adding lime mud to weak wash to provide seeds for precipitation to occur on mud particles instead of on metal substrate.
Journal articles
Magazine articles
Combustion behavior of kraft black liquor droplets from hot
Combustion behavior of kraft black liquor droplets from hot water pretreated hardwood and softwood chips, November 2016 TAPPI JOURNAL
Journal articles
Continuous Time Domain Characterization of Mixing in Agitated Pulp Chests, TAPPI JOURNAL May 2008
Continuous Time Domain Characterization of Mixing in Agitated Pulp Chests, TAPPI JOURNAL May 2008
Journal articles
Chemical and Mechanical Techniques for Improving the Papermaking Properties of Jack Pine TMP Fibers, TAPPI JOURNAL May 2008
Chemical and Mechanical Techniques for Improving the Papermaking Properties of Jack Pine TMP Fibers, TAPPI JOURNAL May 2008
Journal articles
An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part A: Background and Assumptions, TAPPI JOURNAL November 2008
An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part A: Background and Assumptions, TAPPI JOURNAL November 2008
Journal articles
Tailoring Softwood Kraft Pulp Properties by Fractionation and Refining, TAPPI JOURNAL November 2008
Tailoring Softwood Kraft Pulp Properties by Fractionation and Refining, TAPPI JOURNAL November 2008
Journal articles
Toward Predicting the Char Bed Shape in Kraft Recovery Boilers, TAPPI JOURNAL October 2008
Toward Predicting the Char Bed Shape in Kraft Recovery Boilers, TAPPI JOURNAL October 2008
Journal articles
Improvement of the Fiber-Bonding Capacity of Unbleached Recycled Pulp by the Laccase/Mediator Treatment, TAPPI JOURNAL October 2008
Improvement of the Fiber-Bonding Capacity of Unbleached Recycled Pulp by the Laccase/Mediator Treatment, TAPPI JOURNAL October 2008
Journal articles
Black Liquor Spraying Experiments With Six Splashplate Nozzles in Two Recovery Boilers, TAPPI JOURNAL October 2008
Black Liquor Spraying Experiments With Six Splashplate Nozzles in Two Recovery Boilers, TAPPI JOURNAL October 2008