Paper360 - March/April 2015 - (Page 46)

techlink | INSIDE carbon footprints of the bleached pulp. A comparison of the data from the different scenarios showed a large range of carbon footprints for the chemicals used for pulp bleaching. Although the focus has been on carbon footprints, the contributions to other environmental effects commonly included in LCAs were also assessed and only minor differences between the alternative bleaching sequences were found. PAPERMAKING A comparison of five optical surface topography measurement methods Marja Mettänen and Ulrich Hirn TJ SUMMARIES THE PAPERS SUMMARIZED HERE ARE from the January 2015 issue of TAPPI Journal, an online publication of relevant and timely peer-reviewed research delivered via email and free to all TAPPI members. To receive TAPPI Journal, join TAPPI at JANUARY PULPING Impact of wood chip leaching pretreatment on wood chemical composition Ricardo B. Santos, José Lívio Gomide, and Peter W. Hart Examines the effect of wood chip acid leaching pretreatment on non-process elements removal and its impact on wood chemical components. Acid leaching treatments were carried out using two different acid pretreatment approaches: (1) acidified water and (2) filtrate from an acidic bleaching stage. Optimization experiments were performed to identify the most suitable leaching conditions with regard to non-process elements removal and chemical oxygen demand generation. Incorporation of an acid leaching stage significantly reduced 46 Paper360º MARCH/APRIL 2015 The results of optical surface topography measurement techniques have been questioned in the past because of possible measurement artifacts due to light penetration into the paper. This study compared the topography measurement results from five optical techniques: laser profilometry, shapefrom-focus, stripe projection, chromatic sensing, and photometric stereo. These techniques were tested on coated and uncoated papers with a PPS roughness range from 0.7 μm to 7.7 μm. The researchers made the measurement results directly comparable by measuring exactly the same regions on the paper samples and registering the resulting the non-process elements content in the wood chips. BLEACHING Life cycle assessment of ECF bleaching sequences with focus on carbon footprint Pia Jour, Karin Halldén, and Eva Wackerberg This study presents a life cycle assessment (LCA) of bleached eucalyptus kraft pulp production in Brazil. The entire production system was investigated, starting with forestry and ending with bleached pulp at the gate of the pulp mill. Alternative bleaching sequences were compared for three different scenarios using somewhat different elemental chlorine-free (ECF) sequences: Dhot(EPO) DD, Dhot(EPO)DP, and aZeDP. For each scenario, the alternative bleaching sequences studied resulted in similar PAPERMAKING. In copy paper, different measurement techniques produce similar aligned surface topography maps, but for the smoother WFC grade, the images are not as alike.

Table of Contents for the Digital Edition of Paper360 - March/April 2015

Guest Editorial
Over the Wire
TAPPI's Centennial: A Celebration 100 Years in the Making
Precision Alignment of Winders
Single-stream Waste Processing
iRoll at Irving
Fully Automated Continuous Digester
Twin Roll Press Upgrade
TAPPI Journal Summaries
Effluent Treatment
Microfibrils to Transform Paper Furnish
Consolidation Watch
Knowledge Builder
New Energy Windfall
Power from Waste
Safety Survey
Association News
Online Exclusives
Advertisers Index

Paper360 - March/April 2015