Consultant Sets Record Straight on TCF Yield Assertion
Recycled Paper News*
This letter submitted by Neil McCubbin, of N. McCubbin Consultants, is intended to clarify an apparent erroneous statement in an article published in Recycled Paper News. Archie Beaton, director of the Chlorine-Free Products Association, did not respond to several telephone calls to discuss this issue. - Editor
We recently read an article written by Archie Beaton in the June 1997 issue of Recycled Paper News (The Case of Totally Chlorine Free Bleaching) that cites a paper Neil McCubbin presented earlier in 1997 on the subject of the effects of oxygen delignification on process yield.
The paper concerned was presented at the International Emerging Technologies Conference in Orlando in March 1997 and was subsequently published in Pulp and Papermagazine.
The article appears to be a response to one by Douglas Pryke in a previous issue of Recycled Paper News. Beaton's article asserts that, "A study presented at the International Emerging Technologies Conference in March 1997 by Neil McCubbin also confirms that oxygen delignification improves actual yield."
I did not make any such statement either in the cited paper or elsewhere. My paper reviewed the literature and other information available from several independent researchers. It concluded that laboratory work by a number of researchers working independently suggested that there is a potential to use oxygen delignification along with modified digester operations and perhaps screen upgrades to improve overall yield in the production of kraft pulp in existing mills.
I suggested that this be investigated more thoroughly in a full-scale mill. As you may have noticed TAPPI has scheduled a "mini-conference" on the subject of yield this year, showing that this is a subject of considerable interest and uncertainty.
We were not pleased to see the context of the above erroneous citation, since it implied that my paper supported Mr. Beaton's assertion that TCF processes have higher yield than ECF. By mixing the issues of oxygen delignification and TCF in the same paragraph, and by using the word "also" as you did, you are misleading less-knowledgeable readers and defaming me in the eyes of the knowledgeable ones.
I rely on a reputation for being factual and objective in my professional activities and in NOT taking up the banner for any particular interest group. Our company has been successful in bidding for several significant projects in the past 10 years because the committees awarding the contracts specifically wished an engineer with knowledge of the pulp and paper industry who is independent of any special interest group, and who is widely recognized as such.
By attributing such doctrinaire, unsupported statements to me you damage my reputation and our company's ability to obtain business. We have never seen any data to support the assertion that TCF bleaching results in better yield than the established chlorine-based and ECF processes. There have been some statements by operators of TCF mills that there is no loss of yield, but never, to our knowledge, have qualified personnel with first hand knowledge of TCF operations claimed a gain in yield.
We are of the opinion that there is probably some yield loss in a TCF mill and recent data from UPM-Kymmene and Metsa-Rauma support this view.
The field is developing and it will probably be some time before that TCF technology is stabilized, at which point reliable yield comparisons will hopefully be available from mill-scale data.
We would be interested in reading the study on ECF and TCF yields after oxygen delignification that was cited in the paragraph before the mention of the McCubbin paper.
It is quite legitimate to promote a particular way of making paper if you believe it to be environmentally superior, safer, less costly, etc. However, erroneous statements serve neither Mr. Beaton's organization nor ourselves. Neither does coupling unrelated facts in one paragraph with the potential for misinterpretation by readers.
If Mr. Beaton feels that there are any specific statements in any of the publications or verbal presentations by me or my colleagues that support the contention that TCF pulping improves yield, please feel free to contact me to discuss them. Perhaps there is a misunderstanding.
If Mr. Beaton can provide support for his assertions that I made the statements discussed above then we would withdraw this letter.
Mr. Beaton's assertions have been reproduced in the Chlorine-Free Products Association's Guide to TCF and PCF Papers. We trust that that publication will also be corrected.
*Used with permission from Recycled Paper News.