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Anhydrous ammonia storage vessels in the pulp and paper industry, TAPPI JOURNAL, April 1997, Vol. 80(4)

Anhydrous ammonia storage vessels in the pulp and paper industry, TAPPI JOURNAL, April 1997, Vol. 80(4)

Shop talk: reducing voc emissions with thermal oxidation units, TAPPI JOURNAL, December 1997, Vol. 80(12)

Shop talk: reducing voc emissions with thermal oxidation units, TAPPI JOURNAL, December 1997, Vol. 80(12)

Service with a smile: john d. callahan named the 1997 herman l. joachim distinguished service award winner, TAPPI JOURNAL, April 1997, Vol. 80(4)

Service with a smile: john d. callahan named the 1997 herman l. joachim distinguished service award winner, TAPPI JOURNAL, April 1997, Vol. 80(4)

Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)

Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)

1994 polymers, laminations and coatings conference highlights technology basics, TAPPI JOURNAL, December 1994, Vol. 77(12)

1994 polymers, laminations and coatings conference highlights technology basics, TAPPI JOURNAL, December 1994, Vol. 77(12)

Extend the life of your hoists, TAPPI JOURNAL, February 1994, Vol. 77(2)

Extend the life of your hoists, TAPPI JOURNAL, February 1994, Vol. 77(2)

Understanding and minimizing the safety hazards of the deinking process, TAPPI JOURNAL, July 1994, Vol. 77(7)

Understanding and minimizing the safety hazards of the deinking process, TAPPI JOURNAL, July 1994, Vol. 77(7)

World’s Most Northerly Paper Mill Makes Sustainable Choices, Paper360º January/February 2024

TAPPI Journal Summaries, Paper360º January/February 2024

Effects of different soda loss measurement techniques on brownstock quality, TAPPI Journal July 2024

ABSTRACT: The efficiency of the kraft recovery plant, bleaching process, and paper machine are affected when black liquor carryover from the brownstock washers is not controlled well. Measuring soda loss within a mill can vary from using conductivity, either in-situ or with a lab sample of black liquor filtrate squeezed from the last stage washer, to measuring absolute sodium content with a lab sodium specific ion probe or spectrophotometer. While measuring conductivity has value in tracking trends in black liquor losses, it is not an acceptable method in reporting losses in absolute units, typically in lb/ton of pulp. This is further complicated when trying to benchmark soda loss performance across a fleet of mills with multiple washer lines. Not only do the testing methods vary, but the amount of bound soda on high kappa pulps can be significant. This variability creates inconsistent results, and studies are needed to understand the effect of different testing methods on the pulp quality. In this study, soda loss is expressed as sodium sulfate (Na2SO4). Four different methods to measure soda content in pulp off commercial brownstock washers were studied: full digestion (FD), washing soaking overnight and washing (WSW), soaking in boiling water and stirring 10-min (SW-10), and squeeze-no wash (Sq). Total, washable, and bound sodium sulfate calculations were determined for each soda content measuring technique using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed bound and washable sodium sulfate amounts significantly depend on which soda measurement technique was used. In addition, the soda results were correlated with the pulp kappa numbers. As the kappa number increases, bound soda increases, regardless of the soda measurement method used. Impacts of high sodium sulfate in brownstock are also discussed.