50 Years of Chip Quality
A short 50 years ago, I started work at Weyerhaeuser’s Pulp R&D lab in Everett, Washington with degrees in Wood Technology and Pulp and Paper Science. This combination allowed me to pursue chip quality from the unique perspective of forest to the product. One of my daughters asked me one night while I was looking at some chip sample photos “How do you make a living knowing about chips?” I don’t remember my answer, but I am still active and challenged “knowing about chips.”
During those decades, there have been significant accomplishments in supplying uniform and high-value chips to pulp mills. Longwood and tree-length logging, wood handling and debarking has managed wood costs as harvested tree diameters drastically decreased. As woodyards aged and no longer matched the wood supply, chip mills are placed both near and far from mills to replace woodyards and to economically transport chips from a larger supply circle. Woods chipping with flail delimbing/debarking provides both incremental and stable supply from smaller tracts and thinnings. Chip storage is done with stacker/reclaim systems that eliminate compaction that results in deterioration from high temperatures, allows blending and achieves reliable first-in/first-out with minimum fines generation. The risk of chip pile fires has virtually been eliminated. With the appreciation of chip thickness as a key chip property, chip screening systems can control chip thickness and fines levels. Good relationships with chip suppliers and those transporting and handling chips have almost eliminated plastic contamination. Wood product residual chip suppliers have the capability of producing chips that are no longer described as “those chips we don’t want but have to buy to keep the mill running.” Chip quality control programs can measure size distribution, including thickness, of representative samples taken with automated sampling devices. Chip costs, however, continue to rise due to demand, seasonal variability, labor and fuel needed to transport longer distances. We do have the opportunity to produce and deliver chips with a higher value that offsets this cost by being more consistent with each pulp mill’s unique needs, especially uniformity. Appreciation of this value is still on the horizon for most mills.
There are, however, some significant disappointments in my 50-year career in chips, especially since chips have always been more than half of the variable cost of making pulp. Precision chipper maintenance is required to consistently produce a narrow chip size distribution. It takes both knowledge and commitment to do this. Both seem to have waned. A 50-year-old chipper can still make good chips. Again due to lack of maintenance, there are chip thickness screening systems that do no better than the rudimentary gyratory screens they replaced. Chip magnets are positioned to remove virtually nothing. Dozers manicure chip piles, only increasing compaction and producing fines. Chip inventory strategy seems too often the FISH system (first-in/still here). Most of these issues are easily identified with representative chip sampling and good testing. Data will drive the economic justification for maintenance and change.
Chip quality control is my biggest frustration. Excellent programs around the industry were implemented and produced sound data until around 2005. Mills started to do things like decrease staffing, forgot to adequately train new testers, allowed unreliable methods to creep in and sampling shortcuts to be taken. Two managers of large pulp mills even told me that “We don’t need to test our chips. We can’t do anything about the quality, anyway!” Well, the cost of chip quality data certainly shouldn’t be the reason for this. To establish and maintain a great program costs $0.25 to $0.35 per bone dry ton. Without sound and representative chip quality data, a chip buyer and pulp mill cannot make correct decisions on production, processing and using chips. A key element of restoring the emphasis on chip quality is providing easy access to the fundamentals of chip production, correct methods of sampling and guidance in problem-solving. The “Chip Quality Manual” was published initially under the American Pulpwood Association flag and revised in 2005 by FRA’s Western Region. Another revision is in the works. This manual will contain the fundamental information to manage a chip quality control program, solve chip quality problems and facilitate communication between the suppliers and buyers of chips on the value of chip quality. You will hear more about this later this year.