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Techno-economic analysis of hydrothermal carbonization of pulp mill biosludge, TAPPI Journal March 2023
ABSTRACT: For many mills, the biosludge from wastewater treatment is difficult to recycle or dispose of. This makes it a challenging side stream and an important issue for chemical pulping. It often ends up being burned in the recovery or biomass boiler, although the moisture and non-process element (NPE) contents make it a problematic fuel. Biosludge has proven resistant to attempts to reduce its moisture. When incinerated in the biomass boiler, the heat from dry matter combustion is often insufficient to yield positive net heat. Mixing the sludge with black liquor in the evaporator plant for incineration in the recovery boiler is more energy efficient, but is still an additional load on the evaporator plant, as well as introducing NPEs to the liquor. In this study, treating the biosludge by hydrother-mal carbonization (HTC), a mild thermochemical conversion technology, is investigated. The HTC process has some notable advantages for biosludge treatment; taking place in water, it is well suited for sludge, and the hydrochar product is much easier to dewater than untreated sludge. In this study, two HTC plant designs are simulated using IPSEpro process simulation software, followed by economic analysis. Low temperature levels are used to minimize investment costs and steam consumption. The results show that if the sludge is incinerated in a biomass boiler, payback periods could be short at likely electricity prices. The HTC treatment before mixing the sludge with black liquor in the evaporator plant is profitable only if the freed evaporator capacity can be used to increase the firing liquor dry solids content.
Journal articles
Magazine articles
Research on flame-retardant paper prepared by the method of in-pulp addition of ammonium polyphosphate, TAPPI Journal May 2023
ABSTRACT: At present, the production of flame-retardant paper usually uses the impregnation method of phosphorus-nitrogen flame retardants in paper. There are few reports on the application of an in-pulp addition method. In this paper, the solubility of ammonium polyphosphate (APP) and its effect on flame-retardant paper were investigated for use in an in-pulp addition method. It was found that APP particles were square, with an average particle size of 21.88 µm. The particle size decreased significantly after immersion in water at 25°C for 24 h. Furthermore, most of the APPs were dissolved after immersion in water at 90°C for 0.5 h, and the residuals agglomerated and their shape turned into an amorphous form. The APP possessed strong electronegativity and could partially ionize in water. The solubility of APP was 0.18 g/100 mL water at 25°C and increased quickly when the temperature was higher than 30°C. Therefore, APP should be added to the pulp at temperatures below 30°C. The tensile strength of the paper initially increased with the addition of APP, and it reached the maximum value when the APP content was 10% and then gradually decreased. The limiting oxygen index (LOI) value of the paper was 28.7% when the added amount of APP was 30% and cationic polyacrylamide (CPAM) was 0.08%, reaching the flame-retardant level.
Magazine articles
Editor's Note: Bright future for coating at ACFS, TAPPI JOUR
Editor's Note: Bright future for coating at ACFS, TAPPI JOURNAL November 2010
Journal articles
Magazine articles
Citrus-based hydrocolloids: A water retention aid and rheology modifier for paper coatings, TAPPI Journal July 2019
ABSTRACT: The rheological and dewatering behavior of an aqueous pigmented coating system not only affects the machine runnability but also affects the product quality. The current study describes the use of natural hydrocol-loids derived from citrus peel fibers as a rheology modifier in paper coating applications. The results were compared with carboxymethyl cellulose (CMC) in a typical paper coating system. Water retention of the coating formulation was increased by 56% with citrus peel fibers compared to a default coating, and it also was higher than a CMC-containing coating. The Brookfield viscosity of paper coatings was found to increase with citrus peel fibers. Compared to CMC, different citrus peel fibers containing coating recipes were able to achieve similar or higher water retention values, with no change or a slight increase in viscosity. Coatings were applied on linerboard using the Mayer rod-coating method, and all basic properties of paper were measured to assess the impact of citrus peel fiber on the functional value of the coatings. Paper properties were improved with coated paper containing citrus peel fibers, including brightness, porosity, smoothness, surface bonding strength, and ink absorption.
Journal articles
Magazine articles
The evolution of reel statistical methods, TAPPI Journal June 2019
ABSTRACT: Multiple statistical methods for calculating the variance partition analysis (VPA) of reel data have existed for decades. In the paper industry, VPA is also commonly known as reel statistics. VPA commonly consists of total variance (TOT) that is then divided into three components: cross direction (CD), machine direction (MD), and residual (RES). A common mathematical procedure is referred to as ANOVA (analysis of variance). TAPPI Standard Test Method T 545 “Cross-machine grammage profile measurement (gravimetric method)” addresses paper testing and includes the ANOVA equations that have also been used to analyze scanning data.In the 1990s, TAPPI published TIP 1101-01 “Calculation and partitioning of variance using paper machine scanning sensor measurements,” which contained simple formulas that were easy to implement and could be used by a nov-ice to generate statistics on a spreadsheet. All involved quality control system (QCS) suppliers agreed to support this common method in their QCS. TIP 1101 was recently revised, and this paper concerns the analysis of data collected from a scanning sensor in a QCS and the creation of a common method for the calculation of reel statistics by TAPPI’s Process Control Division.
Journal articles
Magazine articles
Lignin-based resins for kraft paper applications, TAPPI Journal November 2019
ABSTRACT: We investigated miscanthus (MS) and willow (W) lignin-furfural based resins as potential reinforce-ment agents on softwood and hardwood kraft paper. These resins might be sustainable alternatives to the commercial phenolformaldehyde (PF) resins. Phenol is a petrochemical product and formaldehyde has been classified as a carcinogen by the U.S. Environmental Protection Agency. The lignin used in this study was derived from hot water extraction (160ºC, 2 h) of MS and W biomass, and may be considered sulfur-free. These biorefinery lignins were characterized for their chemical composition and inherent properties via wet chemistry and instrumental techniques. The resin blends (MS-resin and W-resin) were characterized for their molecular weight, thermal behavior, and mechanical properties. Mechanical properties were measured by the resin’s ability to reinforce softwood and hard-wood kraft papers. The effect of adding hexamethylenetetramine (HMTA), a curing agent, to the resin was also examined. Mixtures of PF and lignin-based resins were investigated to further explore ways to reduce use of non-renewables, phenol, and carcinogenic formaldehyde. The results show that lignin-based resins have the potential to replace PF resins in kraft paper applications. For softwood paper, the highest strength was achieved using W-resin, without HMTA (2.5 times greater than PF with HMTA). For hardwood paper, MS-resin with HMTA gave the highest strength (2.3 times higher than PF with HMTA). The lignin-based resins, without HMTA, also yielded mechanical properties comparable to PF with HMTA.
Journal articles
Magazine articles
Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018
Impact of fiber structure on edge-wicking of highly-sized paperboard, TAPPI JOURNAL August 2018
Magazine articles
A visit to mount st. helens; meta lake illustrates natural recovery following volcanic eruption, TAPPI JOURNAL, April 1994, Vol. 77(4)
A visit to mount st. helens; meta lake illustrates natural recovery following volcanic eruption, TAPPI JOURNAL, April 1994, Vol. 77(4)
Magazine articles
The epa's process safety management program for preventing accidental chemical releases (40 cfr 68), TAPPI JOURNAL, April 1994, Vol. 77(4)
The epa's process safety management program for preventing accidental chemical releases (40 cfr 68), TAPPI JOURNAL, April 1994, Vol. 77(4)
Magazine articles
Suction roll pilot bearing failure due to inadequate lubrication, TAPPI JOURNAL, December 1994, Vol. 77(12), TAPPI JOURNAL, December 1994, Vol. 77(12)
Suction roll pilot bearing failure due to inadequate lubrication, TAPPI JOURNAL, December 1994, Vol. 77(12), TAPPI JOURNAL, December 1994, Vol. 77(12)