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Addition of corn stover arabinoxylan into hardwood during pu
Addition of corn stover arabinoxylan into hardwood during pulping for improved physical properties, TAPPI JOURNAL September 2017
Journal articles
Magazine articles
Decision-making process for the identification of preferred
Decision-making process for the identification of preferred lignin-based biorefinery strategies, TAPPI JOURNAL April 2017
Journal articles
Magazine articles
Evaluation of the particle size of organosolv lignin in the
Evaluation of the particle size of organosolv lignin in the synthesis of resol resins for plywood and their performance on fire spreading, TAPPI JOURNAL July 2017
Journal articles
ABSTRACT: This study investigates the impact of pulp screening on oxygen delignification of high lignin content kraft pulps from spruce wood. An alternative process is proposed: terminating kraft cooking at higher kappa numbers and applying oxygen deligni
ABSTRACT: This study investigates the impact of pulp screening on oxygen delignification of high lignin content kraft pulps from spruce wood. An alternative process is proposed: terminating kraft cooking at higher kappa numbers and applying oxygen delignification directly to unscreened and non-defibrated pulp. The objective is to evaluate whether this non-standard approach can maintain delignification efficiency while improving yield and reducing energy input. The findings demonstrate that screening prior to oxygen delignification is not essential for effective lignin removal or pulp quality. Similar delignification degrees and ISO brightness levels were obtained after oxygen delignification, whether it was performed on screened or unscreened pulps. Notably, the delignification rate in the oxygen stage was the same for the non-standard procedure as for pulp from the standard procedure with the reject fractionremoved prior to the oxygen stage. No significant differences were seen in fiber morphology, brightness level, orbrightness stability. The amount of total fiber charges in pulps not screened before oxygen delignification was slightly higher than in screened pulps.
Journal articles
ABSTRACT: Lignin’s potential as a source of sustainable aromatic compounds is significant, but its utilization is currently limited by its chemical reactivity. Chemical reactivity of lignin depends on the present functional groups, such as hydroxyl, metho
ABSTRACT: Lignin’s potential as a source of sustainable aromatic compounds is significant, but its utilization is currently limited by its chemical reactivity. Chemical reactivity of lignin depends on the present functional groups, such as hydroxyl, methoxy, and carbonyl groups. Therefore, in this study, multivariate analysis-based chemometric models have been developed for rapid determination of aliphatic hydroxyl (Alp-OH) and phenolic hydroxyl (Ph-OH) groups in lignin samples. Two chemometric models, principal component regression (PCR) and partial least squares regression (PLSR), were established with Fourier transform infrared spectroscopy (FTIR) spectral data of 28 lignin samples. Both the models were developed based on raw and pretreated spectroscopic data with Savitky-Golay (S-G) filtering and standard normal variate (SNV) and multiplicative scatter correction (MSC). The predictive performance of the PLSR model is better for predicting Alp-OH (R2 = 0.94%), syringyl-OH (R2 = 0.96%), guaiacyl-OH (R2 = 0.98%), p-hydroxyphenyl (R2 = 0.93%), and total Ph-OH groups (R2 = 0.97%) with the data pretreated by MSC. Finally, the predicted results of these parameters for three new samples for the developed models are found to be very close to the estimated values by NMR.
Journal articles
Magazine articles
Value creation by converting pulp mill flue gas streams to green fuels, TAPPI Journal March 2023
ABSTRACT: Climate change mitigation induces strong growth in renewable electricity production, partly driven by shifts in environmental policies and regulation. Intermittent renewable electricity requires supporting systems in the form of sustainable hydrocarbon chemicals such as transportation fuels. Bulk chemical production fits well into a pulp mill environment, given their large volumes, stable operation, and ample supply of biomass-based carbon feed-stock in the form of flue gases. Until now, the utilization of the flue gases from conventional operation of a pulp mill has received little attention. Harnessing these flue gases into usable products could offer additional value to mill operators, while also diversifying their product portfolio. However, electricity-based fuels and products require extra energy in the conversion step and may not be commercially competitive with current fossil products under the current regulation. There might also be uncertainties about future commodity prices. Thus, the objective of this study is to estimate the economic competitiveness and the added value of selected side products that could be produced alongside conventional pulp and paper products. A typical modern pulp mill is modeled in different product configurations and operational environments, which allows testing of various development paths. This illustrates how the overall energy and mass balance of a pulp mill would react to changes in different final products and other parameters. The focus of the study is in synthetic methanol, which is produced from flue gases and excess resources from the mill, with minimal interference to the pulping process. The results aid in assessing the necessity and magnitude of a premium payment for subsidizing green alter-natives to replace current fossil fuels and chemicals. Additionally, the results function as an indicator of the development state of the pulp and paper industry in the turmoil of climate change regulation. The results indicate that power-to-X systems offer one more viable pathway alternative for broadening the product portfolio of the pulp and paper sector, as well as opening new flexibility measures and services to grid stabilization. Market conditions were found to have a significant impact on the perceived profitability.
Journal articles
Exploratory study on how sub-ply fiber orientation affects t
ABSTRACT: The transition to 100% biobased packaging presents considerable challenges, particularly in the development of a petroleum-free barrier. Generally, biobased barriers exhibit lower flexibility compared to traditional barriers, thereby increasing the risk of cracking during the converting process. The present study examines the possibility of optimizing the substrate to reduce cracking in brittle barriers. Five three-ply composites were fabricated using commercial paperboard to enable a composite with different fiber orientation in the individual plies. The different orientations achieved varying mechanical properties, including strain-atbreak and folding resistance, with a ranking that is comparable to a standard multi-ply paperboard. The composites were subjected to creasing at five distinct depths to assess the area percent of barrier cracks across the crease bead. Micro-cracks appeared on the surface before larger coating cracks were registered. As expected, the area percent of barrier cracks increased significantly with greater creasing depths. The orientation of the bulky middle ply showed little difference in the cracking propensity. However, by replacing the stiffer bottom ply with a ply of lower stiffness, the cracking propensity was significantly reduced without a substantial loss in mechanical properties. Hence, these findings indicate that it is possible to reduce the cracks in the barrier by modifying the fiber orientation in the different plies.
Journal articles
Improving barrier performance of coated paper and paperboard
ABSTRACT: Market demand for barrier coated packaging paper and paperboard has been on a steady rise and is forecasted to further increase. As a result, there is a continued interest in improving barrier coating functionalities, which is currently an active area of investigation. In this work, a multi-layer approach was adopted that involved applying a biowax emulsion, latex, or a combination of biowax and latex top coating layer onto the kaolin/latex (20/80, 50/50, 65/35, or 70/30) precoated solid bleached sulfate (SBS) paperboard. Our main objective was to demonstrate the effect of these top coating layers on various barrier properties, especially water vapor transmission rate (WVTR) at high relative humidity (RH) and high temperature (90% RH; 38°C), known as tropical/jungle test conditions. While the top coat with latex and/or biowax showed dramatic improvement in both water resistance (Cobb) and WVTR, the biowax coating increased contact angle significantly compared to the latex top coat. Contact angle increased from about 65° for the latex top coat to as high as 96° for the biowax top coat. Generally, it is much more difficult to improve WVTR at the jungle conditions below 100 g/m2/day, even with the high aspect ratio platy pigment. However, using the coating strategies adopted in this study, we were able to achieve WVTR values notably below 50 g/m2/day at the tropical test conditions, as well as significant improvements in regard to fold crack barrier integrity at high kaolin clay usage.
Journal articles
Prediction of residual calcium carbonate (CaCO3) in the lime
ABSTRACT: In a kraft pulp mill, the rotary lime kiln is responsible for converting calcium carbonate (CaCO3) into calcium oxide (CaO) to be reused in the causticizing plant. An important parameter of the calcination efficiency and the product quality is the amount of CaCO3 not converted to CaO, commonly defined as residual carbonate. This parameter is usually determined through laboratory analysis, which introduces delays in process control and limits the ability to make timely operational adjustments. This work presents a predictive model that functions as a soft sensor for the residual carbonate in a lime kiln of a Brazilian kraft pulp mill. This model was able to estimate residual CaCO3 every 30 min using routinely measured online process variables, which is a considerable reduction from the 6-h average laboratory measurement. The correlation coefficient (r) between the model predictions and the mill values was 0.83, with a mean absolute error (MAE) of 0.33%. Considering the effect of the residence time throughout the lime kiln proved to be decisive in obtaining a satisfactory prediction result. After model validation, a variable importance analysis showed that the carbon monoxide (CO) concentration in the stack flue gas (in ppm), secondary air temperature (in oC), and fan speed (in %) were the most influential variables in predicting the residual carbonate content. Combined with commonly used operation expertise, this subset of variables can serve as additional information to achieve smoother lime kiln operation.
Journal articles
Magazine articles
Experimental investigations into fold cracking of double coated barrier dispersion coatings, TAPPI Journal November 2024
ABSTRACT: The trend for replacing single-use plastics with fiber-based barrier coated board packaging has prompted a significant amount of research. There are many proposed ways of providing suitable packaging for applications like food service. Among these are dispersion coated barriers on board, as well as laminated boards that can be produced using conventional polyethylene (PE) or new biodegradable plastics. Minerals have also been shown to be suitable additives to these coatings for improving barrier performance through surface chemistry and by increasing the tortuosity of the pathway through the barrier layer. They also improve the cost effectiveness of the layer by lowering the material cost and raising the solids content, and by improving hold out of the functional layers, leading to a reduction in the amount of barrier coating needed to meet a given performance requirement. Minerals can also aid in the barrier handling in terms of rheology and reduced “stickiness,” as well as blocking of the films. When incorporated as fillers into extruded films, improved adhesion of the film to the board has been reported. One of the remaining challenges is the potential for cracking at the fold during converting and the loss of barrier performance that this can lead to. In this work, we systematically looked at the impact of mineral type and level in a dispersion coating. We assessed the differences in performance resulting from different coating application methods for the precoat layer by looking at the cracking tendency and loss of barrier functionality after folding for both the precoat alone and the final double coated sheets. Barrier results include moisture vapor transmission rate (MVTR), viscous vegetable oil, and the fluid blue stain in industrial methylated spirits (IMS) and Cobb water absorption, both before and after folding.