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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
Nonwood pulping: use of jute cuttings and caddis in Bangladesh, TAPPI JOURNAL September 2013
Nonwood pulping: use of jute cuttings and caddis in Bangladesh, TAPPI JOURNAL September 2013
Journal articles
Digester thinning: Erosion-corrosion of internal flow channel headers, TAPPI JOURNAL August 2014
Digester thinning: Erosion-corrosion of internal flow channel headers, TAPPI JOURNAL August 2014
Journal articles
A laboratory study of recoveryboiler smelt shattering, TAPPI JOURNAL August 2014
A laboratory study of recoveryboiler smelt shattering, TAPPI JOURNAL August 2014
Journal articles
Could biomass-fueled boilers be operated at higher steam temperatures? Part 1: Laboratory evaluation of candidate superheater alloys, TAPPI JOURNAL August 2014
Could biomass-fueled boilers be operated at higher steam temperatures? Part 1: Laboratory evaluation of candidate superheater alloys, TAPPI JOURNAL August 2014
Journal articles
Pressures on webs in wound rolls due to winding and contact, TAPPI JOURNAL February 2014
Pressures on webs in wound rolls due to winding and contact, TAPPI JOURNAL February 2014
Journal articles
Effect of silicon on properties of causticized calcium carbonate produced in wheat straw soda pulping, TAPPI JOURNAL July 2014
Effect of silicon on properties of causticized calcium carbonate produced in wheat straw soda pulping, TAPPI JOURNAL July 2014
Journal articles
Market projections of cellulose nanomaterial-enabled products - Part 2: Volume estimates, TAPPI JOURNAL June 2014
Market projections of cellulose nanomaterial-enabled products - Part 2: Volume estimates, TAPPI JOURNAL June 2014
Journal articles
The contribution of pulp brightness and optical brightening agents to paper whiteness, TAPPI JOURNAL March 2014
The contribution of pulp brightness and optical brightening agents to paper whiteness, TAPPI JOURNAL March 2014