Skip to page content
USDA Forest Service
  
Treesearch

Research & Development Treesearch

 
Treesearch Home
About Treesearch
Contact Us
Research & Development
Forest Products Lab
International Institute of Tropical Forestry
Northern
Pacific Northwest
Pacific Southwest
Rocky Mountain
Southern
Help
 

GeoTreesearch


Science.gov - We Participate


USA.gov  Government Made Easy


Global Forest Information Service

US Forest Service
P.O. Box 96090
Washington, D.C.
20090-6090

(202) 205-8333

You are here: Home / Search / Publication Information
Bookmark and Share

Publication Information

(216 KB)

Title: Single fiber lignin distributions based on the density gradient column method

Author: Boyer, Brian; Rudie, Alan W.

Date: 2007

Source: Proceedings of TAPPI engineering, pulping and environmental conference: 2007 October 21-23; Jacksonville, FL. Atlanta, GA: TAPPI Press, 2007: [35] pages.

Publication Series: Miscellaneous Publication

Description: The density gradient column method was used to determine the effects of uniform and non-uniform pulping processes on variation in individual fiber lignin concentrations of the resulting pulps. A density gradient column uses solvents of different densities and a mixing process to produce a column of liquid with a smooth transition from higher density at the bottom to lower density at the top. Properly prepared pulp fibers float in the column, stabilizing at the level where the mixed solvent density equals the density of the fiber. Because lignin is the lowest density component of pulp fibers and has the largest influence on fiber density, the column effectively separates fibers by lignin concentration and allows them to be counted and the distribution of lignin concentrations determined. Ten experimental kraft pulps and three commercial pulps were evaluated. The laboratory pulps were produced from a single loblolly pine tree using 2.5-mm and 10-mm chips. All cooks used a 24% effective alkali (EA) charge on wood, 6-to-1 liquor-to-wood ratio, and 30% sulfidity. The cooking schedule was constant at 60 min rise to temperature and 240 min at temperature. The maximum cooking temperature was varied from 150°C to 170°C to provide a kappa number variation from about 60 to approximately 20. Pulps produced from 2.5-mm-thick chips gave uniform density distributions that were accurately modeled with a standard normal distribution. However, pulps produced using 10-mm chips contained an extended low density (high kappa number) tail that can be modeled as a second, high-standard-deviation distribution. The two distributions can be explained as that portion of the wood chips with ready access to pulping chemicals and rate controlled by pulping kinetics, and the interior portion of the chip where chemical penetration is slow and the pulping rate is controlled by diffusion. The commercial pulps show variations in the lignin concentration standard deviation that demonstrate improved uniformity when using modified continuous cooking processes.

Keywords: Lignin analysis, lignin, loblolly pine, pulping, sulphate pulping process, chemical reactions, plant fibers, chemical composition, solvents, wood chips, bleaching, fibers, lignin chemistry, density gradient column method, softwoods, pulping, pulp and paper processes, sulfate pulping, delignification, pulp density, chips, kinetics

Publication Notes:

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

XML: View XML

Citation:


Boyer, Brian; Rudie, Alan W. 2007. Single fiber lignin distributions based on the density gradient column method. Proceedings of TAPPI engineering, pulping and environmental conference: 2007 October 21-23; Jacksonville, FL. Atlanta, GA: TAPPI Press, 2007: [35] pages.

 


 [ Get Acrobat ]  Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.