The Xanthate Method of Grafting: XI. Grafting of Methylmethacrylate on Hardwood Pulp

1986 ◽  
pp. 97-105
Author(s):  
Claude Daneault ◽  
Bohuslav V. Kokta
Keyword(s):  
Hardwood Pulp

Use of cold tolerant eucalyptus species as a partial replacement for southern mixed hardwoods

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 29-35 ◽  
Author(s):  
PETER W. HART ◽  
DALE E. NUTTER
Keyword(s):  
Potential Method ◽  
The United States ◽  
Partial Replacement ◽  
Growth Time ◽  
Eucalyptus Species ◽  
Cold Tolerant ◽  
Hardwood Pulp ◽  
Time Required ◽  
The Cost ◽  
Operational Data

During the last several years, the increasing cost and decreasing availability of mixed southern hardwoods have resulted in financial and production difficulties for southern U.S. mills that use a significant percentage of hardwood kraft pulp. Traditionally, in the United States, hardwoods are not plantation grown because of the growth time required to produce a quality tree suitable for pulping. One potential method of mitigating the cost and supply issues associated with the use of native hardwoods is to grow eucalyptus in plantations for the sole purpose of producing hardwood pulp. However, most of the eucalyptus species used in pulping elsewhere in the world are not capable of surviving in the southern U.S. climate. This study examines the potential of seven different cold-tolerant eucalyptus species to be used as replacements for, or supplements to, mixed southern hardwoods. The laboratory pulping and bleaching aspects of these seven species are discussed, along with pertinent mill operational data. Selected mill trial data also are reviewed.

From biorefineries to bioproducts: conversion of pretreated pulp from biorefining streams to lignocellulose nanofibers

TAPPI Journal ◽  
2019 ◽  
Vol 18 (4) ◽  
pp. 233-241
Author(s):  
CHENGGUI SUN ◽  
RICHARD CHANDRA ◽  
YAMAN BOLUK
Keyword(s):  
Energy Consumption ◽  
Enzymatic Hydrolysis ◽  
Rheological Behavior ◽  
Material Basis ◽  
Softwood Pulp ◽  
Energy Consumptions ◽  
Hardwood Pulp ◽  
The Stability ◽  
Lignocellulose Nanofibers

This study investigates the use of pretreatment and enzymatic hydrolysis side streams and conversion to lignocellulose nanofibers. We used a steam-exploded and partial enzymatic hydrolyzed hardwood pulp and an organosolv pretreated softwood pulp to prepare lignocellulose nanofibers (LCNF) via microfluidization. The energies applied on fibrillation were estimated to examine the energy consumption levels of LCNF production. The energy consumptions of the fibrillation processes of the hardwood LCNF production and the softwood LCNF production were about 7040-14080 kWh/ton and 4640 kWh/ton on a dry material basis, respectively. The morphology and dimension of developed hardwood and softwood LCNFs and the stability and rheological behavior of their suspensions were investigated and are discussed.

Bleaching optimization at WestRock mill in Covington, Virginia

TAPPI Journal ◽  
2016 ◽  
Vol 15 (9) ◽  
pp. 581-586 ◽  
Author(s):  
RICARDO B. SANTOS ◽  
PETER W. HART ◽  
DOUGLAS C. PRYKE ◽  
JOHN VANDERHEIDE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hydroxide ◽  
Chlorine Dioxide ◽  
Capital Expenditures ◽  
Equipment Repair ◽  
Optimization Program ◽  
Hardwood Pulp ◽  
Improved Performance

The WestRock mill in Covington, VA, USA, initiated a long term diagnostic and optimization program for all three of its bleaching lines. Benchmarking studies were used to help identify optimization opportunities. Capital expenditures for mixing improvement, filtrate changes, equipment repair, other equipment changes, and species changes were outside the scope of this work. This focus of this paper is the B line, producing southern hardwood pulp in a D(EP)DD sequence at 88% GE brightness. The benchmarking study and optimization work identified the following opportunities for improved performance: nonoptimal addition of caustic and hydrogen peroxide to the (EP) stage, carryover of D0 filtrate to the (EP) stage, and carryover of (EP) filtrate to the D1 stage. As a result of actions the mill undertook to address these opportunities, D0 kappa factor decreased about 5%, sodium hydroxide consumption in the (EP) stage decreased about 35%, chlorine dioxide consumption in the D1 stage decreased about 25%, and overall bleaching cost decreased about 15%.

Wood fibre - cement composites by extrusion

2000 ◽  
Vol 27 (3) ◽  
pp. 543-552 ◽  
Author(s):  
Yixin Shao ◽  
Shylesh Moras ◽  
Nilgun Ulkem ◽  
George Kubes
Keyword(s):  
Cement Composite ◽  
Temperature Cycling ◽  
Wood Fibre ◽  
Flexural Behavior ◽  
Cement Composites ◽  
Building Product ◽  
Toughness Index ◽  
Composites Materials ◽  
Fibre Cement ◽  
Hardwood Pulp

Wood fibres derived from both hardwood and softwood, being relatively inexpensive and in ample supply, have gained increasing popularity in the fibre-cement building product industry. Presently, the manufacture of most wood fibre - cement composites employs the Hatschek process. The purpose of this paper is to examine the feasibility of using extrusion technology for the production. Wood fibre - cement sheets, composed of both hardwood and softwood fibres of different fibre contents, were fabricated using an auger-type extruder. The flexural behavior, moisture content, water absorption, and density of all batches were evaluated. To investigate the weathering durability of the extruded composites, materials were also subjected to a temperature-cycling test and a natural exposure weathering test. With a relative ease of manufacture and a much cleaner production, extrusion was found to be a suitable means for making cement composite thin sheets with up to 8% fibres by weight. The extruded composites exhibited a performance comparable to or even better than that of the Hatschek products. Hardwood fibres, which are cheaper and more available than the softwood fibres, were found to be more suitable for extrusion production in terms of the extrudability, finished surface, and long-term mechanical properties.Key words: wood fibre - cement composites, hardwood pulp, softwood pulp, extrusion, strength, toughness index, temperature cycling, natural weathering.

Pre-bleaching of mixed hardwood pulp with sulphuric acid

2010 ◽  
Vol 7 (1-2) ◽  
pp. 30-35
Author(s):  
D. Weley Siddhartha ◽  
Pradeep Kumar ◽  
Surendra P. Singh
Keyword(s):  
Sulphuric Acid ◽  
Hardwood Pulp

Refining Characteristics of Hardwood Pulp Using Straight- and Curved-bar Plates: A Time Series Study

2019 ◽  
Vol 51 (5) ◽  
pp. 45-60
Author(s):  
Huan Liu ◽  
Jixian Dong ◽  
Xiya Guo ◽  
Xiaojun Jiang ◽  
Chong Luo ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Study ◽  
Hardwood Pulp ◽  
Series Study

Features of the Bleached Sulfate Hardwood Pulp Production When Using the Birch and Aspen Wood Resources in the Ratio of Seventy-to-Thirty

2015 ◽  
Vol 347 (5) ◽  
pp. 174-182
Author(s):  
L Milovidova ◽  
◽  
T Koroleva ◽  
M Romanov ◽  
E Okulova ◽  
...  
Keyword(s):  
Aspen Wood ◽  
Hardwood Pulp ◽  
Pulp Production

scholarly journals TOTAL CHLORINE-FREE BLEACHING OF SULFATE HARDWOOD PULP WITH HYDROGEN PEROXIDE

2019 ◽  
pp. 287-294
Author(s):  
Фирдавес (Firdaves) Харисовна (Harisovna) Хакимова (Hakimova) ◽  
Константин (Konstantin) Андреевич (Andreevich) Синяев (Sinyaev)
Keyword(s):  
Hydrogen Peroxide ◽  
Mechanical Strength ◽  
Small Proportion ◽  
Pulp Fibers ◽  
Pulp Bleaching ◽  
Sulfate Pulp ◽  
Environmentally Safe ◽  
Hardwood Pulp ◽  
High Degree ◽  
Pulp Production

The work is devoted to the study of the possibility and feasibility of environmentally safe bleaching of sulfate hardwood pulp by TCF-technology without the use of traditional oxygen and ozone as a delignifying reagent. The TCF-technology of sulphate hardwood pulp bleaching (scheme Pa-EP-Pd-Aac-P-A) was developed with only one oxidizing reagent – hydrogen peroxide. It is proposed to carry out of pulp delignification with hydrogen peroxide in an acid medium conditions, additional delignification and bleaching – with hydrogen peroxide in an alkaline medium conditions. Soft oxidizing effect of hydrogen peroxide used at all stages of bleaching provides selectivity of the process along with ecological compatibility of the scheme. The mechanical strength of pulp varies during bleaching in accordance with the change of the degree of delignification and is very moderate, and the total loss of pulp fibers is only 6.1%. Production of hardwood sulfate pulp, as well as sulfite, is associated with difficulties caused by a "harmful" resin at a small proportion of extractives. The proposed scheme of bleaching provides a high degree of resin removal and contributes to the depitching, i.e. decision of very important problems in sulphate hardwood pulp production.

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