EFFECT OF PULPING MOUNTAIN PINE BEETLE-KILLED WOOD ON TALL OIL SOAP RECOVERY, 2008 Engineering, Pulping and Environmental Conference

ARE YOU A TAPPI MEMBER? TAPPI members have exclusive, FREE access to technical conference papers and presentations six months after the conference in TAPPI's e-library. The e-Library offers:

• Unlimited access to more than 18,000+ documents
• Fast, robust search engine for fast search results
• Members get FREE access to conference proceedings, TAPPI JOURNAL articles, Paper360º articles, archived Solutions! articles, and much more
• View thousands of technical paper abstracts
• Ability to search by keyword, title, author, events or industry segment

*Technical papers and presentations are available for sale immediately following the conferences before the 6 month embargo period.

Please Note: This document will be available in PDF format in the "My Electronic Documents" link on the home page once your order has been completed. Please make sure you have the latest version of Acrobat Reader. Click on the Acrobat Reader icon to check for the latest version, it’s FREE. To print a hardcopy of a PDF file correctly you must have a postscript printer. If you are not sure if your printer is a postscript printer please refer to your owner’s manual.

Soap solubility tests and soap analyses, using black liquor and soap samples from four British Columbia mills and one Alberta mill pulping very little beetle-killed wood, indicate that tall oil production at mills pulping beetle-killed wood could drop substantially due to higher soap solubility in black liquor, a reduced tendency for the soap to “float” off in storage vessels and skimmers, and lower soap quality (acid number). The changes in soap solubility, and a reduced tendency to float to the surface of the black liquors, are largely a result of changes in the fatty acid (FA) and resin acid (RA) content of the wood, resulting from beetle attack and subsequent fungi infestation. The FA:RA ratio in tall oil produced from soap skimmed in the mills pulping beetle-killed wood has dropped from 1.49:1.86 in the mid-1980s to 0.72:1.28. The solids concentrations at which soap solubility is minimized are now consistently in the 35 to 49% solids range. In the 17 to 32% solids range, where most British Columbia mills try to skim soap, soap solubility increased significantly. While little soap would be recovered in these mills, soap could be expected to precipitate at higher solids concentrations, aggravating evaporator and concentrator scaling problems and accumulating in strong liquor storage tanks, where it could cause further operating problems. Increasing soap concentrations in fired black liquor were found to increase the viscosity and heating value of the black liquor while decreasing the swelling propensity of the liquors, making them much more difficult to burn. Tests in two recovery boilers indicate that without operating modifications, high concentrations of soap in the fired black liquor lower the char bed temperature and increase carryover in the upper boiler.