April 2007
By Graeme Rodden, Editorial Director, Magazines, RISI
In the Chemical Markets column of December 2006, I wrote about an interview I had with one chemical supplier, touching base on a lot of things. One of the topics was cooperation, not only between the pulp and paper producers and the suppliers, but between the suppliers. It was one area where he said there could be a lot more activity.
Lo and behold, recently we received a press release from Buckman Laboratories describing a new cooperative business agreement it has signed with Voith Paper. Voith has developed a new tissue machine, ATMOS, and Buckman has been chosen as its preferred supplier for process chemistry consulting and specialty chemicals supply. As the song states: This could be the start of something big. We hope to have more details about this agreement in an upcoming Chemical Markets column.
Heard on the floor
With chemicals and chemical use becoming a dominant factor in most pulp and papermaking process, it was no surprise that the recent TAPPI Papermakers Conference featured sessions devoted to the subject.
Delegates at the well-attended Additives and Wet End Session heard from three suppliers about new products. Matt Blazey, Ciba Specialty Chemicals, described a new analytical technique, the Ciba Contaminant Analyzer (CCA).
With increased mechanical-based or recovered fiber in furnishes, deposits have increased, causing "deposit storms," as Blazey called them. Deposits on the wires, foils and press section can lead to sheet defects and off-spec production.
Many mills use pitch counts as a forecasting tool, but often the data may not correlate with paper machine conditions. Mills may increase the dose of their current fixative, but the problem could get worse. Pitch counts are time consuming, do not assess true particle size, are operator sensitive and are unable to assess hydrophobicity. Others use turbidity to control deposits but this also has its pitfalls. Turbidity cannot judge good fixation from agglomeration.
With the CCA, one starts with a filtrate sample and a hydrophobic dye is added. The dyed particles are counted and measured with a laser. They are classified in both size and nature. This allows for the optimization of fixation of colloidal contaminants onto fibers/fines.
Ross Meyers, Omya, described a size press filing development. This focuses on commodity grades and is aimed at improving the papermakers' cost situation; it is not really designed to change paper attributes.
Existing starch application systems can be used to apply ultrafine (less than two microns) ground calcium carbonate (GCC) filler. Amounts of 1-3% can be added. The GCC is easy to retain and provides good offset printing properties.
Trials show that there is no effect on strength, caliper or smoothness. There can be improved stiffness and formation. Energy savings are also a benefit.
The starch to GCC ratio can be 4:1, 2:1 or 1:1. The latter would require a rod change. Some buildup in the metering size press heads can be expected. However, rod and roll life are not affected. The GCC can be used with all types of starches. No coating kitchen equipment or additional non-contact drying is needed.
Whiter and brighter
Buckman has developed a proprietary organic coagulant for high-bright grades that enhances the retention of optical brightening agents (OBA), fillers and fluorescent whiteners.
As sheet brightness increases, it can have an effect on paper machine runnability and the cost of making the grade. Gary Headrick noted how the new coagulant does not quench OBA and can be used for all grades. It is a liquid that is directly fed.
Benefits claimed include brighter paper at a lower cost; excellent PCC, titanium dioxide and clay filler retention; superior drainage that allows paper machine speed to be increased or steam consumption reduced; fewer holes and other sheet defects; and reduced linting and dusting.
Headrick provided a couple of mill case studies including one of an uncoated freesheet mill that wanted to increase brightness from 92 to 96-98. The coagulant was fed at the suction side of the fan pump. At 96 brightness, there was no change in the OBA required. The mill had fewer sheet defects and paper machine efficiency improved. The estimated ROI was $830,000.
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