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Magazine articles
A novel unit operation to remove hydrophobic contaminants, TAPPI Journal April 2020
ABSTRACT: For mills making paper with recovered fiber, removal of hydrophobic contaminants is essential for trouble-free operation of paper machines. Significant cost savings on paper machine operation can be achieved by reducing deposits, which results in better quality, reduced downtime, increased fiber yield, and reduced energy consumption. Bubble nucleation separation (BNS) is a relatively new process for removing hydrophobic particles. When vacuum is applied to a slurry, dissolved gas bubbles nucleate on hydrophobic particles and drag them to the surface for easy removal. We constructed a 16-L batch unit to evaluate the effect of operating parameters on removal of hydrophobic particles, using statistical design of experiments. These results were used to guide our design of a 16-L continuous unit. We tested this unit on laboratory and mill samples. The removal of 60%•80% of hydrophobic particles was achieved with a low reject rate of < 2%.Following on this success, we built a 200-L pilot unit and tested it in our pilot plant. With promising results there, we installed the pilot unit at a commercial paper recycling mill. Over the course of several mill trials, we showed that it was possible to remove a considerable amount of suspended solids from paper machine white water with less than 2% rejects. Unfortunately, due to the unit only treating 50 L/min and the mill flow being 12000 L/min, we were not able treat a sufficient portion of the white water to know whether a large-scale implementation of BNS would improve paper machine runnability.
Magazine articles
Leveraging mill-wide big data sets for process and quality i
Authors: Jianzhong Fu and Peter W. Hart | ABSTRACT: The MWV mill in Covington, VA, USA, experienced a long term trend of increasing episodes of paper indents that resulted in significant quantities of internal rejects and production downtime. When traditional troubleshooting techniques failed to resolve the problem, big data analysis techniques were employed to help deter-mine root causes of this negative and increasingly frequent situation. Nearly 6000 operating variables were selected for a deep dive, multi-year analysis after reviewing mill-wide process logs and 60000+ PI tags (data points) collected from one of the major data historian systems at the MWV Covington mill. Nine billion data points were collected from November 2011 to August 2014. Strategies and methods were developed to format, clean, classify, and sort the various data sets to compensate for process lag time and to align timestamps, as well as to rank potential causes or indicators. GE Intelligent Platforms software was employed to develop decision trees for root cause analysis. Insights and possible correlations that were previously invisible or ignored were obtained across the mill, from pulp-ing, bleaching, and chemical recovery to the papermaking process. Several findings led the mill to revise selected process targets and to reconsider a step change in the drying process. These changes have exhibited significant impacts on the mill’s product quality, cost, and market performance. Mill-wide communications of the identified results helped transform the findings into executable actions. Several projects were initiated.
Journal articles
Three-Dimensional Observation of Coated Paper by Confocal Laser Scanning Microscope, TAPPI JOURNAL, February 2006, Vol. 5(2) (393 KB)
Three-Dimensional Observation of Coated Paper by Confocal Laser Scanning Microscope, TAPPI JOURNAL, February 2006, Vol. 5(2) (393 KB)
Journal articles
A Low-Temperature, Black Liquor Gasifier Model for Use in WinGEMS, TAPPI JOURNAL, February 2006, Vol. 5(2) (242 KB)
A Low-Temperature, Black Liquor Gasifier Model for Use in WinGEMS, TAPPI JOURNAL, February 2006, Vol. 5(2) (242 KB)
Journal articles
Soot blower lance tube corrosion in recovery boilers, TAPPI JOURNAL, January 2006, Vol. 5(1) (436 KB)
Soot blower lance tube corrosion in recovery boilers, TAPPI JOURNAL, January 2006, Vol. 5(1) (436 KB)
Journal articles
The applicability of natural colorants in papermaking, TAPPI
The applicability of natural colorants in papermaking, TAPPI JOURNAL, July 2006, Vol. 5(7)
Journal articles
Characterizing the Pore Structures of Paper Coatings with Scanning Probe Microscopy, TAPPI JOURNAL, March 2006, Vol. 5(3) (470KB)
Characterizing the Pore Structures of Paper Coatings with Scanning Probe Microscopy, TAPPI JOURNAL, March 2006, Vol. 5(3) (470KB)
Journal articles
Purification of Peroxide-Bleached TMP Waterby Dissolved Air
Purification of Peroxide-Bleached TMP Waterby Dissolved Air Flotation, TAPPI JOURNAL, May 2006, Vol. 5(5) (395 KB)
Journal articles
Characterizing Liquid-Vapor Phase Change Phenomena in Impuls
Characterizing Liquid-Vapor Phase Change Phenomena in Impulse Technology With Resistivity Probes, TAPPI JOURNAL, May 2006, Vol. 5(5) (280 KB)
Journal articles
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, Novem
Editor's Notes: Ready for a Test Drive, TAPPI JOURNAL, November, 2006