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Journal articles
Magazine articles
Open Access
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
Open Access
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
Magazine articles
Open Access
Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018

Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018

Journal articles
Open Access
Combined effect of fiber fines and dissolved organics on tissue properties, TAPPI JOURNAL April 1988 88APR141

Combined effect of fiber fines and dissolved organics on tissue properties, TAPPI JOURNAL April 1988

Journal articles
Open Access
Correlating the on-line measurement of ultrasonic velocity with strength properties, TAPPI JOURANL April 1988 88APR149

Correlating the on-line measurement of ultrasonic velocity with strength properties, TAPPI JOURANL April 1988

Journal articles
Open Access
Measurement of strains in a paper tensile specimen using computer vision and digital image correlation-Part 2: Tensile specimen test, TAPPI JOURNAL April 1988 88APR153

Measurement of strains in a paper tensile specimen using computer vision and digital image correlation-Part 2: Tensile specimen test, TAPPI JOURNAL April 1988

Journal articles
Open Access
Fourth press operation in Japan, TAPPI JOURNAL April 1988 88APR83

Fourth press operation in Japan, TAPPI JOURNAL April 1988

Journal articles
Open Access
Energy savings through hot pressing, TAPPI JOURNAL April 1988 88APR89

Energy savings through hot pressing, TAPPI JOURNAL April 1988

Journal articles
Open Access
Automatic winder slitter positioning using a programmable logic controller, TAPPI JOURNAL August 1988

Automatic winder slitter positioning using a programmable logic controller, TAPPI JOURNAL August 1988

Journal articles
Open Access
Panel discussion: Vendor-led turnkey projects-pros and cons, TAPPI JOURNAL August 1988

Panel discussion: Vendor-led turnkey projects-pros and cons, TAPPI JOURNAL August 1988

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