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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
Application of ATR-IR measurements to predict the deinking efficiency of UV-cured inks, TAPPI Journal January 2022
ABSTRACT: In recent years, ultraviolet (UV)-curable ink has been developed and widely used in various printing applications. However, using UV-printed products (UV prints) in recovered paper recycling causes end-product dirt specks and quality issues. A new method was developed that can distinguish UV prints from other prints by means of attenuated total reflectance infrared (ATR-IR) spectroscopy. Application of this method could allow more efficient use of UV prints as raw materials for paper recycling.First, a mill trial was performed using UV prints alone as raw materials in a deinked pulp (DIP) process. Second, test prints were made with four types of UV inks: a conventional UV ink and three different highly-sensitive UV inks. Each print sample had four levels of four-color ink coverage patterns (100%, 75%, 50%, and 25%). Next, deinkability of all prints was evaluated by laboratory experiments. Finally, each print was measured using the ATR-IR method, and the relationship between the IR spectra and deinkability was investigated. Mill trial results showed that UV prints caused more than 20 times as many dirt specks as those printed with conventional oil-based ink. There were variations in recycling performance among UV prints taken from bales used for the mill trial. Lab tests clearly revealed that not all UV-printed products lead to dirt specks. In order to clarify the factors that affected deinkability of UV prints, the print samples were investigated by lab experiments. Key findings from lab experiments include: œ The number of dirt specks larger than 250 µm in diameter increased as the ink coverage increased. œ Higher ink coverage area showed stronger intensity of ATR-IR spectral bands associated with inks. These results indicate that deinkability of UV prints could be predicted by analysis of ATR-IR spectra. œ Finally, the method was applied for assessment of recovered paper from commercial printing presses. It was confirmed that this method made it possible to distinguish easily deinkable UV prints from other UV prints. Based on these findings, we concluded that the ATR-IR method is applicable for inspection of incoming recovered paper.
Journal articles
Magazine articles
Investigation of the Cellulose-Water Relationship by the Pressure Plate Method, TAPPI Journal July 2022
ABSTRACT: The swelling and water retention properties of pulp fibers are of basic importance in papermaking.
Journal articles
Characterization of refined papermaking pulps using hydrodynamic parameters from filtration analysis, TAPPI JOURNAL May 2015
Characterization of refined papermaking pulps using hydrodynamic parameters from filtration analysis, TAPPI JOURNAL May 2015
Journal articles
Financial performance, capital expenditures, and international activities of the north american pulp and paper industry, TAPPI JOURNAL, October 1997, Vol. 80(10)
Financial performance, capital expenditures, and international activities of the north american pulp and paper industry, TAPPI JOURNAL, October 1997, Vol. 80(10)
Journal articles
Fate of trace elements in energy recovery from recycled paper sludge, TAPPI JOURNAL, September 1997, Vol. 80(9)
Fate of trace elements in energy recovery from recycled paper sludge, TAPPI JOURNAL, September 1997, Vol. 80(9)
Journal articles
Other ways to use ozone in a bleaching sequence, TAPPI JOURNAL, September 1997, Vol. 80(9)
Other ways to use ozone in a bleaching sequence, TAPPI JOURNAL, September 1997, Vol. 80(9)
Journal articles
1997 Environmental Conference reflects continuing high profile of industry environmental concerns and achievements, TAPPI JOURNAL, September 1997, Vol. 80(9)
1997 environmental conference reflects continuing high profile of industry environmental concerns and achievements, TAPPI JOURNAL, September 1997, Vol. 80(9)
Magazine articles
Recycling 'low value' post-consumer fibers to improve quality and reduce costs, TAPPI JOURNAL, September 1997, Vol. 80(9)
Recycling 'low value' post-consumer fibers to improve quality and reduce costs, TAPPI JOURNAL, September 1997, Vol. 80(9)
Journal articles
TAPPI JOURNAL April 1998; Vol. 81; No.4 - EPA Creates New Assessment Modeling, TAPPI JOURNAL, April 1998, Vol. 81(4)
TAPPI JOURNAL April 1998; Vol. 81; No.4 - EPA Creates New Assessment Modeling, TAPPI JOURNAL, April 1998, Vol. 81(4)