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Magazine articles
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
A case study review of wood ash land application programs in North America, TAPPI Journal February 2021
ABSTRACT: Several regulatory agencies and universities have published guidelines addressing the use of wood ash as liming material for agricultural land and as a soil amendment and fertilizer. This paper summarizes the experiences collected from several forest products facility-sponsored agricultural application programs across North America. These case studies are characterized in terms of the quality of the wood ash involved in the agricultural application, approval requirements, recommended management practices, agricultural benefits of wood ash, and challenges confronted by ash generators and farmers during storage, handling, and land application of wood ash.Reported benefits associated with land-applying wood ash include increasing the pH of acidic soils, improving soil quality, and increasing crop yields. Farmers apply wood ash on their land because in addition to its liming value, it has been shown to effectively fertilize the soil while maintaining soil pH at a level that is optimal for plant growth. Given the content of calcium, potassium, and magnesium that wood ash supplies to the soil, wood ash also improves soil tilth. Wood ash has also proven to be a cost-effective alternative to agricultural lime, especially in rural areas where access to commercial agricultural lime is limited. Some of the challenges identified in the review of case studies include lengthy application approvals in some jurisdictions; weather-related issues associated with delivery, storage, and application of wood ash; maintaining consistent ash quality; inaccurate assessment of required ash testing; potential increased equipment maintenance; and misconceptions on the part of some farmers and government agencies regarding the effect and efficacy of wood ash on soil quality and crop productivity.
Journal articles
Magazine articles
Continuous tannin extraction by use of screw reactor, TAPPI Journal February 2021
ABSTRACT: A pilot-size screw reactor (extraction unit) was used for tannin extraction of spruce. Yield of the same magnitude or better was obtained when comparing a screw reactor with batch reactors. A longer presoaking time in water seemed to be better than a short one for obtaining higher yield. A higher yield is obtained with lower dry-water ratio, which suggests that the internal diffusion in bark does not determine mass transfer as much as is the case without presoaking of bark. The higher dry-water ratio decreased the yield. The prior soaking of the bark also minimized the mechanical reactor feeding problems (clogging). The benefits of a screw reactor likely are that run time changes for different process conditions are flexible; it simplifies design and construction of an industrial unit for tannin production; and it saves space because of the need for fewer and smaller intermediate storage tanks.
Journal articles
New trends in deinking technology removing difficult inks from wastepaper, TAPPI JOURNAL, February 1991, Vol. 74(2)
New trends in deinking technology removing difficult inks from wastepaper, TAPPI JOURNAL, February 1991, Vol. 74(2)
Journal articles
Color removal from kraft bleach-plant effluents by trichoderma sp., TAPPI JOURNAL, January 1991, Vol. 74(1)
Color removal from kraft bleach-plant effluents by trichoderma sp., TAPPI JOURNAL, January 1991, Vol. 74(1)
Journal articles
Bleaching deinked pulps, TAPPI JOURNAL, January 1991, Vol. 74(1)
Bleaching deinked pulps, TAPPI JOURNAL, January 1991, Vol. 74(1)
Journal articles
Fine paper properties and the effects of wet-end starch when using deinked recycled fiber in an alkaline system, TAPPI JOURNAL, May 1991, Vol. 74(5)
Fine paper properties and the effects of wet-end starch when using deinked recycled fiber in an alkaline system, TAPPI JOURNAL, May 1991, Vol. 74(5)
Journal articles
Thermomechanical pulping of douglas-fir: mill and lab experiences at smurfit newsprint corp., TAPPI JOURNAL, October 1991, Vol. 74(10)
Thermomechanical pulping of douglas-fir: mill and lab experiences at smurfit newsprint corp., TAPPI JOURNAL, October 1991, Vol. 74(10)
Journal articles
Effect of fungal pretreatment on strength and optical properties of softwood and hardwood kraft pulps, TAPPI JOURNAL, October 1991, Vol. 74(10)
Effect of fungal pretreatment on strength and optical properties of softwood and hardwood kraft pulps, TAPPI JOURNAL, October 1991, Vol. 74(10)
Journal articles
State-of-the-art predictive maintenance programs, TAPPI JOURNAL, August 1992, Vol. 75(8)
State-of-the-art predictive maintenance programs, TAPPI JOURNAL, August 1992, Vol. 75(8)