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Utilization of kraft pulp mill residuals, TAPPI Journal February 2022

ABSTRACT: Kraft pulp mills produce on average about 100 kg of solid residuals per metric ton of pulp produced. The main types of mill waste are sludge from wastewater treatment plants, ash from hog fuel boilers, dregs, grits, and lime mud from causticizing plants and lime dust from lime kilns. Of these, about half is disposed of in landfills, which highlights the need and potential for waste recycling and utilization. Sludge is either incinerated in hog fuel boilers to generate steam and power or used in various forms of land application, including land spreading, composting, or as an additive for landfill or mine waste covers. The majority of hog fuel boiler ash and causticizing plant residues is landfilled. Alkaline residuals can be conditioned for use in land application, manufacture of construction materials, and production of aggregates for road work. This technical review summarizes residuals utilization methods that have been applied in pulp and paper mills at demonstration- or full-scale, and therefore may act as a guide for mill managers and operators whose goal is to diminish the costs and the environmental impact of waste management.

Preparing prehydrolyzed kraft dissolving pulp via phosphotungstic acid prehydrolysis from grape branches, TAPPI Journal January 2022

ABSTRACT: Dissolving pulp was successful prepared via phosphotungstic acid (PTA) prehydrolysis kraft (PHK) cooking followed by an elementary chlorine-free (ECF) bleaching process from grape branches. The effects of prehydrolysis temperature, reaction time, and PTA concentration that potentially affect the quality of dissolving pulp product on chemical components of pulp were studied via an orthogonal experiment. The structure of lignin was activated during the PTA prehydrolysis phase, and lignin was easily removed during the following cooking process. Thus, relatively mild conditions (140°C, 100 min) can be used in the cooking process. During the prehydrolysis phase, temperature exhibited the most significant influence on the cellulose purity of the obtained pulp fiber, followed by reaction time and PTA concentration. The optimized prehydrolysis conditions were as follows: prehydrolysis temperature, 145°C; reaction time, 75 min; and PTA concentration, 1 wt%. Whether the excessively high prehydrolysis temperature or prolonging the reaction time did not favor the retention of long chain cellulose, the delignification selectivity for the cooking process could not be further improved by excessive PTA loading. Under these prehydrolysis conditions, 94.1% and 29.0% for a-cellulose content and total yield could be achieved after the given cooking and bleaching conditions, respectively. Moreover, the chemical structure and crystal form of cellulose were scarcely changed after PTA prehydrolysis, which could be confirmed by results from Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). PTA prehydrolysis could be considered as an alternative method for preparing PHK dissolving pulp under relatively mild cooking conditions.

World’s Largest MVR Evaporation Plant for Sulphite Spent Liquor at Sappi Saiccor Pulp Mill, Paper360º July/August 2022

TAPPI Journal Summaries, Paper360º July/August 2022

TAPPI Journal Summaries, Paper360º July/August 2022

Effects of debonding agents and refining on the properties of deinked pulp, TAPPI JOURNAL, July 2008

Effects of debonding agents and refining on the properties of deinked pulp, TAPPI JOURNAL, July 2008

2008 EPE/IBBC: Getting More From What We Have, Paper360° June/July 2008

2008 EPE/IBBC Conferences Explore Pulping, Bleaching, Engineering, Environmental and Bioenergy Issues, Paper360º June/July 2008

Reappraisal of the role of turpentine vapor in noncondensible gas explosions, TAPPI JOURNAL April 2010

Reappraisal of the role of turpentine vapor in noncondensible gas explosions, TAPPI JOURNAL April 2010

Effects of impregnation time on hardwood kraft pulp characteristics and papermaking potential â?¢ a mill study, TAPPI JOURNAL April 2010

Effects of impregnation time on hardwood kraft pulp characteristics and papermaking potential • a mill study, TAPPI JOURNAL April 2010

Ozone-enhanced bleaching of softwood kraft pulp, TAPPI JOURNAL August 2010

Ozone-enhanced bleaching of softwood kraft pulp, TAPPI JOURNAL August 2010

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp â?¢ part 1: impact of oxidative extraction on chlorine dioxide stoichiometry, TAPPI JOURNAL August 2010

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp • part 1: impact of oxidative extraction on chlorine dioxide stoichiometry, TAPPI JOURNAL August 2010