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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.
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Enzymatic treated viscose fibers functionalized by chitosan, TAPPI JOURNAL August 2018
Enzymatic treated viscose fibers functionalized by chitosan, TAPPI JOURNAL August 2018
Journal articles
Magazine articles
Evaluation of novel drum chipper technology: pilot-scale production of short wood chips, TAPPI Journal October 2019
ABSTRACT: Impregnation of wood chips with acidic pulping liquors is improved when using short chip lengths. If the average wood chip length is too short, conventional chipping technology will generate excess small material, such as pin chips and fines. The possibility of using newly developed drum chipping technology to produce short-length wood chips was evaluated with a pilot drum chipper operating at different drum velocities and in-feed angles. With a drum velocity of 30 m/s, the average wood chip lengths and the combined fractions of pin chips and fines were 24 mm and 3.3%, 22 mm and 4.2%, and 17 mm and 8.5%. The highest fractions of total accept chips (large and small accepts), 89% to 90% without screening, were observed for drum velocities of 30•34 m/s and average wood chips lengths of 21•22 mm. The results indicate the potential of drum chipping technology for producing short wood chips with relatively high fractions of accept chips and tolerable fractions of pin chips and fines.
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Characterization of chia plant (Salvia hispanica) for pulping, TAPPI Journal October 2020
ABSTRACT: In this paper, chia plant was characterized in terms of chemical, morphological, and anatomical properties. Chia plant was characterized with low a-cellulose (30.5%); moderate lignin (23.2%) with syringyl to guaiacyl ratio of 1.41; and shorter fiber length (0.67 mm) with thinner cell wall (1.91 µm) and good flexibility coefficient (71.44). Anatomical features showed that chia plant consists of vessels, fibers, parenchyma cells, and collenchyma cells. Chia plant pulping was evaluated in soda-anthraquinone (soda-AQ) and formic acid/peroxyformic acid (FA/PFA) processes. Chia plant was difficult to delignify in the alkaline process. The FA/PFA process produced higher pulp yield at the same kappa number than the soda-AQ process. Unbleached soda-AQ chia pulp exhibited good properties in terms of tensile, bursting, and tearing strengths, even at the unrefined stage, due to high drainability of the pulps. Alkaline peroxide bleached FA/PFA pulp exhibited better papermaking properties and 2% higher brightness than the D0(EP)D1 bleached soda-AQ pulp.
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Effects of different ammonium lignosulfonate contents on the crystallization, rheological behaviors, and thermal and mechanical properties of ethylene propylene diene monomer/polypropylene/ammonium lignosulfonate composites, TAPPI Journal January 2020
ABSTRACT: Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has an excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the AL contents on the crystallization behaviors, rheological properties, thermal properties, and mechanical properties of the composites. The results showed that the AL content had a noticeable impact on the performance of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.
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Editorial: Special pulping and engineering issues of TAPPI Journal yield important recovery cycle research, TAPPI Journal June 2024
ABSTRACT: The June issue of TAPPI Journal, which is dominated by recovery cycle topics, is the last PEERS issue organized by Dr. Peter Hart, the fomer editor-in-chief who passed away this past May. Peter, who was heavily involved with TAPPI’s Pulp Manufacture Division and various pulping-related committees, also started working with conference technical program planning starting in 2005 with the Engineering, Pulping and Environmental (EPE) Conference, which was the precursor to the more recent Pulping, Engineering, Environmental, Recycling and Sustainability (PEERS) Conference. He was also involved with other conference planning, including that for the International Pulp Bleaching Conference. In addition, Peter was a yearly attendee of such conferences starting as far back as 1990.
Journal articles
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Effects of varying total titratable alkali and causticizing efficiency targets on kraft pulp mill productivity, TAPPI Journal March 2024
ABSTRACT: The kraft mill causticizing area is often overlooked and undervalued when it comes to mill optimization; however, the operation of the causticizing plant has downstream effects on the entire liquor cycle. Setting the right targets for the causticizing plant can have a tremendous effect on mill operating costs, as well as push the production bottleneck from one unit operation to another. The key performance parameters associated with the causticizing plant itself are liquor total titratable alkali (TTA) and causticizing efficiency. Individual facilities choose their TTA and causticizing efficiency targets based on their goals, the limits of their equipment, and past experiences. This gives a variety of operating strategies in practice, but what are the implications for optimizing total titratable alkali and causticizing efficiency, and what level of optimization can be achieved through implementation of modern technology? This paper reviews the results of several different operational strategies and models the effects of these different approaches on kraft mill liquor cycle.
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Repulping of wet strength paper towel with potassium monopersulfate, TAPPI Journal September 2020
ABSTRACT: Potassium monopersulfate (KMPS) was used in repulping of polyamide-epichlorohydrin (PAE)-containing paper towel. The effectiveness of the repulping aid was compared with that of sodium hypochlorite. Addition of a 2.4% KMPS repulping aid achieved complete repulping of the paper towel, resulting in 88% screen yield and about 5% rejects. To reach a similar pulping result, two times the oxidative equivalent amount of sodium hypochlorite had to be used. Compared to the pulp fibers obtained from sodium hypochlorite repulping, those obtained from KMPS repulping had higher physical strength, longer fiber length, and lower fines content. This study demonstrated that KMPS was superior to sodium hypochlorite in repulping of PAE-containing paper towel in terms of effectiveness and pulp quality.
Journal articles
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Does the kappa number method accurately reflect lignin content in nonwood pulps?, TAPPI Journal November 2018
Does the kappa number method accurately reflect lignin content in nonwood pulps?, TAPPI Journal November 2018
Journal articles
Magazine articles
Fate of phosphorus in the recovery cycle of the kraft pulping process, TAPPI Journal March 2020
ABSTRACT: The accumulation of nonprocess elements in the recovery cycle is a common problem for kraft pulp mills trying to reduce their water closure or to utilize biofuels in their lime kiln. Nonprocess elements such as magnesium (Mg), manganese (Mn), silicon (Si), aluminum (Al), and phosphorus (P) enter the recovery cycle via wood, make-up chemicals, lime rock, biofuels, and process water. The main purge point for these elements is green liquor dregs and lime mud. If not purged, these elements can cause operational problems for the mill. Phosphorus reacts with calcium oxide (CaO) in the lime during slaking; as a result, part of the lime is unavailable for slaking reactions. The first part of this project, through laboratory work, identified rhenanite (NaCa(PO4)) as the form of P in the lime cycle and showed the negative effect of P on the availability of the lime. The second part of this project involved field studies and performing a mass balance for P at a Canadian kraft pulp mill.