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Determining operating variables that impact internal fiber bonding using Wedge statistical analysis methods, TAPPI Journal November 2021
ABSTRACT: In this study, Wedge statistical analysis tools were used to collect, collate, clean up, plot, and analyze several years of operational data from a commercial paper machine. The z-direction tensile (ZDT) and Scott Bond tests were chosen as representative of fiber bond strength. After analyzing thousands of operational parameters, the ones with the most significant impact upon ZDT involved starch application method, starch penetration, and the amount of starch applied. Scott bond was found to be significantly impacted by formation and refining. Final calendering of the paper web has also shown an impact on internal fiber bonding.
Journal articles
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Temperature profile measurement applications of moving webs and roll structures with intelligent roll embedded sensor technology, TAPPI Journal November 2021
ABSTRACT: An intelligent roll for sheet and roll cover temperature profiles is a mechatronic system consisting of a roll in a web handling machine that is also used as a transducer for sensing cross-machine direction (CD) profiles. The embedded temperature sensor strips are mounted under or inside the roll cover, covering the full width of the roll’s cross-dimensional length. The sensor system offers new opportunities for online temperature measurement through exceptional sensitivity and resolution, without adding external measurement devices. The measurement is contacting, making it free from various disturbances affecting non-contacting temperature measurements, and it can show the roll cover’s internal temperatures. This helps create applications that have been impossible with traditional technology, with opportunities for process control and condition monitoring. An application used for process analysis services without adding a roll cover is made with “iRoll Portable Temperature” by mounting the sensor on the shell in a helical arrangement with special taping. The iRoll Temperature sensors are used for various purposes, depending on the application. The two main targets are the online temperature profile measurement of the moving web and the monitoring of the roll covers’ internal temperatures. The online sheet temperature profile has its main utilization in optimizing moisture profiles and drying processes. This enables the removal of speed and runnability bottlenecks by detecting inadequate drying capacity across the sheet CD width, the monitoring condition of the drying equipment, the optimization of drying energy consumption, the prevention of unnecessary over-drying, the optimization of the float drying of coating colors, and the detection of reasons for moisture profile errors. This paper describes this novel technology and its use cases in the paper, board, and tissue industry, but the application can be extended to pulp drying and industries outside pulp and paper, such as the converting and manufacture of plastic films.
Journal articles
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Evaluation of rice straw for purification of lovastatin, TAPPI Journal November 2021
ABSTRACT: Cholesterol synthesis in the human body can be catalyzed by the coenzyme HMG-CoA reductase, and lovastatin, a key enzyme inhibitor, can reduce hypercholesterolemia. Lovastatin can be obtained as a secondary metabolite of Aspergillus terreus ATCC 20542. In this study, rice straw of lignocellulose was used in aeration and agitation bath fermentation in a 1-L flask, and a maximal crude extraction rate of 473 mg/L lovastatin was obtained. The crude extract was treated with silica gel (230•400 mesh) column chromatography. Ethyl acetate/ethanol (95%) was used as the mobile phase, and isolation was performed through elution with various ethyl acetate/ethanol ratios. The highest production rate of 153 mg/L was achieved with ethyl acetate/ethanol in a ratio of 8:2. The lovastatin gained from the crude extract was added to 12 fractions treated with 0.001 N alkali, and acetone was then added. After 24 h of recrystallization at 4°C, the extract underwent high-performance liquid chromatography. The purity had increased from 25% to 84.6%, and the recovery rate was 65.2%.
Journal articles
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Control of malodorous gases emission from wet-end white water with hydrogen peroxide, TAPPI Journal October 2021
ABSTRACT: White water is highly recycled in the papermaking process so that its quality is easily deteriorated, thus producing lots of malodorous gases that are extremely harmful to human health and the environment. In this paper, the effect of hydrogen peroxide (H2O2) on the control of malodorous gases released from white water was investigated. The results showed that the released amount of total volatile organic compounds (TVOC) decreased gradually with the increase of H2O2 dosage. Specifically, the TVOC emission reached the minimum as the H2O2 dosage was 1.5 mmol/L, and meanwhile, the hydrogen sulfide (H2S) and ammonia (NH3) were almost completely removed. It was also found that pH had little effect on the release of TVOC as H2O2 was added, but it evidently affect-ed the release of H2S and NH3. When the pH value of the white water was changed to 4.0 or 9.0, the emission of TVOC decreased slightly, while both H2S and NH3 were completely removed in both cases. The ferrous ions (Fe2+) and the copper ions (Cu2+) were found to promote the generation of hydroxyl radicals (HOœ) out of H2O2, enhancing its inhibition on the release of malodorous gases from white water. The Fe2+/H2O2 system and Cu2+/H2O2 system exhibited similar efficiency in inhibiting the TVOC releasing, whereas the Cu2+/H2O2 system showed better perfor-mance in removing H2S and NH3.
Journal articles
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Effects of phosphogypsum whiskers modification with calcium stearate and their impacts on properties of bleached softwood paper sheets, TAPPI Journal September 2021
ABSTRACT: By combining the structural properties and characteristics of phosphogypsum whiskers, a preliminary study on the modification of phosphogypsum whiskers and their application in papermaking was carried out. The effects of reaction temperature, reaction time, and reaction concentration on the solubility and retention of modified phosphogypsum whiskers and the effects of phosphogypsum whiskers on the physical properties of paper under different modified conditions were explored. The research results show that, after the phosphogypsum whiskers are modified with calcium stearate, a coating layer will be formed on the surface of the whiskers, which effectively reduces the solubility of the phosphogypsum whiskers. The best modification conditions are: the amount of calcium stearate relative to the absolute dry mass of the phosphogypsum whisker is 2.00%; the modification time is 30 min, and the modification temperature is 60°C. The use of modified phosphogypsum whiskers for paper filling will slightly reduce the whiteness, folding resistance, burst resistance, and tensile strength of the paper, but the tearing degree and retention of the filler will be increased to some extent.
Journal articles
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A true green cover for industrial waste landfills, TAPPI Journal April 2024
ABSTRACT: Greenhouse gas (GHG) emissions in the United States totaled 5,981 million metric tons of carbon dioxide equivalent (MMT CO2eq) in 2020. Of that, GHG emissions by the pulp and paper sector amounted to 35 MMT CO2eq direct emissions and those by industrial waste landfills summed to 7.4 MMT CO2eq direct emissions. Loss of GHG sinks due to change in land use further contributes to the net GHG emissions. Industrial waste landfills are typically required to comply with certain federal and state regulations, including meeting requirements for final cover systems. Conventional final cover systems have included use of soil covers and/or soil-geosynthetic composite covers. An engineered turf cover provides for an excellent “green” alternative final cover system for industrial waste landfills.This paper discusses various sustainability aspects pertaining to use of an engineered turf final cover, including: (i)significantly low carbon footprint associated with the construction of an engineered turf alternative final coverwhen compared to closure using a traditional or prescriptive cover system; (ii) saving valuable soil and land resourc-es; (iii) saving water resources by reduction in its use during and after construction; (iv) reducing impacts associated with borrow areas; and (v) reducing overall carbon footprint. Further, when using an engineered turf cover, opportunities exist for beneficial reuse of land, including development of solar energy. A brief discussion on the potential fordevelopment of solar energy is included.
Journal articles
Magazine articles
Surface modification of TiO2 with MPS and its effects on the wettability and physical properties of Kawayan Kiling (Bambusa vulgaris Schrad ex. Wendl) handsheets, TAPPI Jouranl April 2024
ABSTRACT: The need for hydrophobic papers has steadily increased over past years. These papers are often sought after as packaging materials and have high demand in the food industry and medicine. In this study, various concentrations of surface-modified TiO2-MPS were added to Kawayan Kiling (B. vulgaris) pulp at the wet-end section of handsheet formation. Surface-modified TiO2-MPS was made from nano-titanium (IV) oxide using 3-(trimethoxysilyl)propyl methacrylate as a coupling agent. The wettability of handsheets and physical properties were tested using various standard methods. Results reveal that the handsheets without surface-modified TiO2-MPS had the lowest water contact angle (WCA), while the handsheet with 12.34% (w/w) surface-modified TiO2-MPS had the highest WCA. At 17% (w/w) surfacemodified TiO2-MPS, the WCA rapidly declined. Handsheets with surface-modified TiO2-MPS have a rougher surface compared to the handsheets without chemicals and handsheets with unmodified TiO2. This roughness made the handsheet hydrophobic. The handsheet with 12.34% (w/w) unmodified TiO2 has a smoother surface than the control handsheet. Energy-dispersive X-ray spectroscopy (EDS) analysis shows that the handsheet with 12.34% (w/w) unmodified TiO2 contained titanium, while the handsheet with 12.34% (w/w) surface-modified TiO2-MPS contained both titanium and silicon. Generally, the physical properties of handsheets improved with surface-modified TiO2- MPS, especially grammage, bulk thickness, tensile index, and water absorptiveness, which showed statistically significant differences across treatments. The tear index did not differ between treatments.
Journal articles
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Convolutional neural networks enhance pyrolysis gas chromatography mass spectrometry identification of coated papers, TAPPI Journal August 2024
ABSTRACT: In the evolving paper industry, accurate identification of coated paper components is essential for sustainability and recycling efforts. This study employed pyrolysis-gas chromatography mass spectrometry (Py-GCMS) to examine six types of coated paper. A key finding was the minimal interference of the paper substrate with the pyrolysis products of the coatings, ensuring reliable analysis. A one-dimensional convolutional neural network (1D-CNN) was employed to process the extracted ion chromatograms directly, simplifying the workflow and achieving a predictive accuracy of 95.2% in identifying different coating compositions. Additionally, the study high-lighted the importance of selecting an optimal pyrolysis temperature for effective feature extraction in machine learning models. Specific markers for coated papers, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene succinate (PBS), polylactic acid (PLA), and waterborne polyacrylates (WP), were identified. This research demonstrates a novel approach to coated paper identification by combining Py-GCMS with machine learning, offering a foundation for further studies in product quality and environmental impact.
Journal articles
Magazine articles
The role of hornification in the deterioration mechanism of physical properties of unrefined eucalyptus fibers during paper recycling, TAPPI Journal February 2024
ABSTRACT: Physical properties of cellulosic paper deteriorate significantly during paper recycling, which hinders the sustainable development of the paper industry. This work investigates the property deterioration mechanism and the role of hornification in the recycling process of unrefined eucalyptus fibers. The results showed that during the recycling process, the hornification gradually deepened, the fiber width gradually decreased, and the physical properties of the paper also gradually decreased. After five cycles of reuse, the relative bonding area decreased by 17.6%, while the relative bonding force decreased by 1.8%. Further results indicated that the physical property deterioration of the paper was closely related to the decrease of fiber bonding area. The fiber bonding area decreased linearly with the reduction of re-swollen fiber width during paper recycling. Re-swollen fiber width was closely related to the hornification. Hornification mainly reduces the bonding area of unrefined eucalyptus fiber rather than the bonding force. The work elucidates the role of hornification in the recycling process of unrefined eucalyptus fibers and the deterioration mechanism of paper physical properties, which will be helpful to control the property deterioration of paper and achieve a longer life cycle.
Journal articles
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Next generation dry strength additives: Leveraging on-site synthesis to develop high performance glyoxalated polyacrylamides, TAPPI Journal January 2024
ABSTRACT: Although glyoxalated polyacrylamides (gPAMs) have been described since the 1950s, the freedom to design new materials based on this chemistry has been limited by practical concerns; namely, a balance between solution concentration and material characteristics must be met to make the economics of gPAM strength additives work for the paper industry. For traditional “delivered” gPAMs, only a very narrow range of polyacrylamide molecular weights and compositions could be considered for glyoxalation. However, the development and successful implementation of automated reactor equipment that allows for the synthesis of gPAMs from glyoxal and polyacrylamide copolymers at the mill, known as “on-site” glyoxalation, obviates the shipping and stability concerns that have traditionally held back gPAM development. As such, on-site generators represent a platform that enables the glyoxalation of materials that would otherwise not have been suitable for use in a traditionally delivered gPAM product. These on-site generators therefore open new avenues for polymer design to allow for the creation of the next generation of strength additives. By leveraging the synthetic freedom of the on-site generators, a suite of high performance gPAMs has been designed, yielding materials that provide both exceptional strength and drainage performance in poor quality furnishes.