Pulp Industry Research Articles

Phosphorus adsorption of a residue from the pulp and paper industry (grits): contributions to tertiary wastewater treatment

Phosphorus adsorption of a residue from the pulp and paper industry (grits): contributions to tertiary wastewater treatment

Enhancing water quality prediction with advanced machine learning techniques: An extreme gradient boosting model based on long short-term memory and autoencoder

Achieving carbon neutrality in the pulp and paper industry necessitates effectively recycling pulp and papermaking wastewater, where continuous monitoring of effluent quality indices is crucial. This study suggests a novel machine learning-based model named LSTMAE-XGBOOST that integrates the feature extraction capabilities of autoencoder, the sequential feature learning capabilities of LSTM, and the high prediction accuracy of XGBOOST. This model is capable of extracting the complex relationships, non-Gaussian characteristics, and time series features from the papermaking wastewater data, and it demonstrates superior predictive performance. Compared to traditional machine learning models, the proposed model exhibits higher prediction accuracy. Specifically, when contrasted with partial least squares regression, LSTMAE-XGBOOST achieves a 40% increase in R2 and a 35% reduction in RMSE. Further comparative assessments against other machine learning-based hybrid models with similar structures confirm the superiority of integrating LSTM and XGBOOST within the hybrid model approach. This study contributes a compelling methodology for modeling effluent quality indices, offering significant implications for environmental management in the pulp and paper industry.

2024 IEEE IAS Pulp and Paper Industry Committee (PPIC) Conference [Society News

2024 IEEE IAS Pulp and Paper Industry Committee (PPIC) Conference [Society News

Corrigendum to “Economic impact of more stringent environmental standard in China: Evidence from a regional policy experimentation in pulp and paper industry” Resources, Conservation and Recycling 158 (2020), 104831

Corrigendum to “Economic impact of more stringent environmental standard in China: Evidence from a regional policy experimentation in pulp and paper industry” Resources, Conservation and Recycling 158 (2020), 104831

Unraveling latent affinity of strategically designed histidine-rich biosurfactant via tannery waste bio-upcycling in environmentally-relevant lignin removal from pulp and paper industry effluent

Bioremediation of pulp and paper industry (PPI) effluent is hindered due to biorefractory lignin. Herein, we demonstrate a lignin-specific designer biosurfactant with synergistic binding sites for enhanced lignin removal from PPI effluent. The histidine rich-cationic lipoprotein biosurfactant (HR-CLB) was synthesized by Bacillus tropicus using tanning industry solid waste, animal fleshing by de novo substrate-dependent synthesis pathway. Interestingly, the HR-CLB anchored functionalized carbon (HR-CLBAFC) demonstrated a high lignin sequestration capacity of 93.2 mg/g HR-CLBAFC at optimized time, 60 min; pH, 5; temperature, 45 °C; and mass of HR-CLBAFC, 1.0 g. The sequestration was confirmed by HR-SEM, UV–Vis., FT-IR, and WCA analyses. The isotherm studies revealed the involvement of Freundlich isotherm (regression coefficient, R2: 0.988) in regulating lignin sequestration onto HR-CLBAFC with a Freundlich constant (Kf) of 16.46 ((mg/g)(L/mg)1/n). Moreover, the kinetics studies divulged the contribution of the pseudo-second-order kinetic model (R2: 0.992) in regulating the dynamic mechanism of lignin sequestration onto HR-CLBAFC with a rate constant (k2) of 0.00022 g/mg min. Additionally, the thermodynamics studies discovered a positive Gibbs free energy (ΔG: +170 kJ/mol) and entropy (ΔS°: +130 kJ/mol), indicating the involvement of chemical interaction during the sequestration. Furthermore, the mechanistic study confirmed the role of an incomplete valence shell of nitrogen in histidine centers of HR-CLB in regulating electrostatic interaction with lignin molecules during the sequestration process. Subsequently, the HR-CLBAFC applied for lignin sequestration from the real-time PPI effluent demonstrated an outstanding sequestration efficiency (>99.4%), confirming the unequivocal potential of the HR-CLBAFC matrix in lignin sequestration from real-time PPI effluent.

Environmental Sustainability Assessment of Tissue Paper Production

The environmental performance of tissue paper varies greatly based on factors such as the type of fibre used as the raw material, the production process and the fuels used to meet the energy requirements. One possible strategy to decrease greenhouse gas emissions in tissue production is the integration of pulp and paper mills and their energy systems at the same site. However, the environmental trade-offs associated with this strategy are still unclear. Therefore, this study aimed (i) to assess for the first time the environmental impacts of tissue paper produced at a typical industrial site in Portugal using slush and market pulp as the main raw material, and (ii) to assess the environmental effects of the integration of bioenergy produced in the pulp mill in tissue production. A life cycle assessment was conducted from cradle to gate using real data from the production of eucalyptus wood, eucalyptus pulp and tissue paper. The results showed that energy consumption in tissue paper production is the main hotspot for most impact categories. When bioenergy is used in tissue production, the environmental impacts decrease by up to 20% for categories other than marine eutrophication and mineral resource scarcity. These results are relevant to support decision making concerning sustainable practices not only for the pulp and paper industry but also for the authorities in charge of defining environmental policies, incentives and tax regulations.

A Review of Welding Process for UNS S32750 Super Duplex Stainless Steel

Super duplex stainless steel UNS S32750 is widely used in marine industries, pulp and paper industries, and the offshore oil and gas industry. Welding manufacturing is one of the main manufacturing processes to make material into products in the above fields. It is of great importance to obtain high-quality welded UNS S32750 joints. The austenite content and ferrite content in UNS S32750 play an important role in determining UNS S32750 properties such as mechanical properties and corrosion resistance. However, the phase proportion between the ferrite phase and austenite phase in the welded joint will be changed during welding. Lots of research has been done on how to weld UNS S32750 and how to obtain welded joints with good quality. In this work, the recent studies on welding UNS S32750 are categorized based on the welding process. The welding process for UNS S32750 will be classified as gas tungsten arc welding, submerged arc welding, plasma arc welding, laser beam welding, electron beam welding, friction stir welding, and laser-MIG hybrid welding, and each will be reviewed in turn. The microstructure and properties of the joints welded using different welding processes will also be discussed. The critical challenge of balancing the two phases of austenite and ferrite in UNS S32750 welded joints will be discussed. This review about the welding process for UNS S32750 will provide people in the welding field with some advice on welding UNS S32750 super duplex stainless steel.

Social-LCA providing new insights and learnings for social responsibility—case pulp and paper industry

Abstract Purpose This paper presents the lessons learnt from testing the ORIENTING S-LCA methodology for a case product of Stora Enso, a globally operating forest industry company. The main purpose of the study was to explore what kind of additional insights and benefits the S-LCA method could provide compared to other existing social responsibility methods and approaches used by companies. Methods The paper briefly describes the applied ORIENTING S-LCA method and its application in the case study, focusing on main learnings gained and development needs identified. The S-LCA methodology proposed in ORIENTING builds upon the UNEP Guidelines for S-LCA (UNEP 2020) and the Handbook for Product Social Impact Assessment (Goedkoop et al. 2020). S-LCA methodology relies on the reference scale approach (RSA) and combines qualitative and quantitative evaluations for assessing social performance and social risk along the product’s life cycle. Social performance assessment approach was applied for company’s own processes covering several life cycle stages and the risk assessment for assessing the supply chain. Results and discussion Based on the case company’s experience, social assessments are currently conducted mainly on company or facility level. Moving towards product-based assessments could help gaining a more transparent view of products’ value chains and bring new possibilities for example to supplier specific sustainability audits. With the product-based S-LCA, the company could more easily identify, e.g., in which life cycle stage they would have most gaps on information and on which social matters, and take different stakeholders’ needs better into consideration in different life cycle stages. Areas that require further development concern especially data availability, assessment efficacy, and formulation of social topics. Conclusions The study demonstrates that the S-LCA methodology offers several benefits when addressing social sustainability issues in the pulp and paper industry. Comprehensive view over different social topics, life cycle perspective, and stakeholder identification are key elements of S-LCA that may support identifying relevant sustainability topics for the purposes of corporate sustainability reporting. Additionally, they can support defining appropriate mitigation actions that will be required for complying with the requirements related to corporate sustainability due diligence.

Thermothelomyces thermophilus cultivated with residues from the fruit pulp industry: enzyme immobilization on ionic supports of a crude cocktail with enhanced production of lichenase.

β-Glucans comprise a group of β-D-glucose polysaccharides (glucans) that occur naturally in the cell walls of bacteria, fungi, and cereals. Its degradation is catalyzed by β-glucanases, enzymes that catalyze the breakdown of β-glucan into cello-oligosaccharides and glucose. These enzymes are classified as endo-glucanases, exo-glucanases, and glucosidases according to their mechanism of action, being the lichenases (β-1,3;1,4-glucanases, EC 3.2.1.73) one of them. Hence, we aimed to enhance lichenase production by Thermothelomyces thermophilus through the application of response surface methodology, using tamarind (Tamarindus indica) and jatoba (Hymenaea courbaril) seeds as carbon sources. The crude extract was immobilized, with a focus on improving lichenase activity, using various ionic supports, including MANAE (monoamine-N-aminoethyl), DEAE (diethylaminoethyl)-cellulose, CM (carboxymethyl)-cellulose, and PEI (polyethyleneimine)-agarose. Regarding lichenase, the optimal conditions yielding the highest activity were determined as 1.5% tamarind seeds, cultivation at 50°C under static conditions for 72h. Moreover, transitioning from Erlenmeyer flasks to a bioreactor proved pivotal, resulting in a 2.21-fold increase in activity. Biochemical characterization revealed an optimum temperature of 50°C and pH of 6.5. However, sustained stability at varying pH and temperature levels was challenging, underscoring the necessity of immobilizing lichenase on ionic supports. Notably, CM-cellulose emerged as the most effective immobilization medium, exhibiting an activity of 1.01 U/g of the derivative (enzyme plus support), marking a substantial enhancement. This study marks the first lichenase immobilization on these chemical supports in existing literature.

Conversion of Lignin to Nitrogenous Chemicals and Functional Materials.

Lignin has long been regarded as waste, readily separated and discarded from the pulp and paper industry. However, as the most abundant aromatic renewable biopolymer in nature, lignin can replace petroleum resources to prepare chemicals containing benzene rings. Therefore, the high-value transformation of lignin has attracted the interest of both academia and industry. Nitrogen-containing compounds and functionalized materials are a class of compounds that have wide applications in chemistry, materials science, energy storage, and other fields. Converting lignin into nitrogenous chemicals and materials is a high-value utilization pathway. Currently, there is a large amount of literature exploring the conversion of lignin. However, a comprehensive review of the transformation of lignin to nitrogenous compounds is lacking. The research progress of lignin conversion to nitrogenous chemicals and functional materials is reviewed in this article. This article provides an overview of the chemical structure and types of industrial lignin, methods of lignin modification, as well as nitrogen-containing chemicals and functional materials prepared from various types of lignin, including their applications in wastewater treatment, slow-release fertilizer, adhesive, coating, and biomedical fields. In addition, the challenges and limitations of nitrogenous lignin-based materials encountered during the development of applications are also discussed. It is believed that this review will act as a key reference and inspiration for researchers in the biomass and material field.

Catalytic influence of alkali and alkali earth metals in black liquor on the gasification process: a review

AbstractDuring the pulping process, either alkali or alkali earth metals are added in a cooking solution to turn wood chips into pulp, and these alkali and alkali earth metals (AAEMs) end up in the black liquor. These AAEMs are known to catalyze the gasification process, by lowering the reaction temperature and degrading tar in the syngas. Of the various black liquor valorization methods, gasification is a promising process that can be integrated into existing pulping processes to recover the process energy via syngas utilization. It is, therefore, important to firmly understand how AAEMs in black liquor catalyze the gasification process. This review paper also discusses how black liquor is generated from both the Kraft pulping and the sulfite pulping process. The paper also examines advances that have been made in terms of an integrated gasification process into the existing pulping process. The paper explores the supercritical water gasification of back liquor and syngas as fuel in the pulp and paper industry. A discussion of the co-gasification of black liquor with either fossil fuels or biomass, focusing on the catalytic effect of AAEMs in the co-gasification process as well as the synergistic effects of fossil fuels and biomass is presented.

Conversion of kraft lignin to hydrocarbons using an integrated molten salt pyrolysis/catalytic hydrotreatment approach

Thermochemical conversion of underutilized lignocellulosic streams such as kraft lignin from the pulp and paper industry has the potential to produce sustainable chemicals and biofuels. We here report a process to continuously convert softwood-based lignoboost lignin to hydrocarbons using a three-step approach: i) liquefaction/dispersion of the lignin in a suitable molten salt, ii) pyrolysis of the liquefied/dispersed lignin in a molten salt mixture (ZnCl2, KCl, and NaCl), to obtain a crude lignin oil and iii) upgrading of the lignin oil using a catalytic hydrotreatment to yield hydrocarbons. Step 1 and 2 were integrated using a twin screw extruder with different heating sections at a scale of 20 g/h lignin input. Besides char, a lignin oil, mainly composed of monomeric phenolics, and propylene were the major products. The highest yield of the latter two products was around 32 wt% (23 wt% crude lignin oil and 9 wt% propylene). The lignin oil was subsequently converted to hydrocarbons using a two-step catalytic hydrotreatment approach (stabilization step using CoMo/Al2O3 catalyst and a further deep hydrotreatment over a NiMo/Al2O3 catalyst). The final liquid product contained less than 0.5 wt% of oxygen and was shown to be rich in (cyclo)alkanes and aromatic hydrocarbons. The carbon yield for the overall conversion of lignin to hydrocarbons was 23 %.

Boron-modified super duplex stainless steels: microstructure, hardness, and industrial applications

In this work was investigated the boron modified super duplex stainless steel processed by spray-forming, to characterize the workpiece using different techniques, among them, optical microscopy, SEM-FEG, X-ray diffraction, Rama spectroscopy and Vickers hardness (VH) and Thermo-Calc software. As result, in this research was verified that in the ferrite phase the Cr element predominates, but in the austenite phase the Fe and Ni elements prevail by the EDS technique. As well as XRD spectra showed different meta-stable phases and (FeCr)2B phase. Besides, the Vickers microhardness measurement was around 460 HV, being much taller than the duplex stainless steel. This alloy can be successfully used in the chemical, oil and gas industries, petrochemical process plants, the pulp and paper industry, pollution control equipment, transportation and for general engineering thanks to their outstanding corrosion resistance and mechanical properties.

Comprehensive Insights into Microbial Lipases: Unveiling Structural Dynamics, Catalytic Mechanism, and Versatile Applications.

Microbial lipases (MLs) are pivotal biocatalysts in lipid biotechnology due to their diverse enzymatic properties and substrate specificity, garnering significant research attention. This comprehensive review explores the significance of MLs in biocatalysis, providing insights into their structure, catalytic domain, and oxyanion hole. The catalytic mechanism is elucidated, highlighting the molecular processes driving their efficiency. The review delves into ML sources, spanning fungi, yeasts, bacteria, and actinomycetes, followed by a discussion on classification and characterization. Emphasizing the scattered findings in the literature, the paper consolidates the latest information on ML applications across various industries, from food and pharmaceuticals to biofuel production and the paper and pulp industry. The review captures the dynamic landscape of ML research, emphasizing their structure-function relationships and practical implications across diverse sectors.

Control of continuous digester kappa number using generalized model predictive control

Kappa number variability at the digester impacts pulp yield, physical strength properties, and lignin content for downstream delignification processing. Regulation of the digester kappa number is therefore of great importance to the pulp and paper industry. In this work, an industrial application of model-based predictive control (MPC), based on generalized prediction control, was developed for kappa number feedback control and applied to a dual vessel continuous digester located in Western Canada. The problem was complicated by the need to apply heat at multiple locations in the cook. In this study, the problem was reduced from a multiple to a single input system by identifying three potential single variable permutations for temperature adjustment. In the end, a coordinated approach to the heaters was adopted. The process was perturbed and modeled as a simple first order plus dead time model and implemented in generalized predictive control (GPC). The GPC was then configured to be equivalent to Dahlin’s controller, which reduced tuning parameterization to a single closed loop time constant. The controller was then tuned based on robustness towards a worst-case dead time mismatch of 50%. The control held the mean value of the kappa number close to the setpoint, and a 40% reduction in the kappa number’s standard deviation was achieved. Different kappa number trials were run, and the average fiberline yield for each period was evaluated. Trial results suggested yield gains of 0.3%–0.5% were possible for each 1 kappa number target increase.

Upgrading of kraft lignin pyrolysis products: Managing sulfur impurities

Pyrolysis stands as a powerful method for the valorization of biomass like kraft lignin, an aromatic-rich and sulfur-containing polymeric by-product from the pulping industry. Sulfur in the raw matrix is released during thermal processes and is redistributed in pyrolysis products. However, the presence of sulfur lowers the quality of products due to its corrosive and toxic character. In this work, commercial activated carbons have been used as adsorbents to remove the main sulfur compounds from the gas phase (i.e., CH3SH, COS, H2S). The analysis of sulfur content in biochar has been performed through SEM-EDXS, while the sulfur content in oils has been obtained by GC–MS analysis. The adsorption of sulfur on the activated carbon bed results in an enhancement of the release of sulfur in the gas phase from 34 % without activated carbon to 44 %. Up to 88 % of H2S removal is achieved after the adsorption step, together with a reduction of the overall sulfur content in the bio-oil rich in intermediates such as guaiacols and alkylated phenols. The residual sulfur contained in the liquid product is lowered to 3 % of the total sulfur in the system, thus improving the quality of the liquid pyrolysis product. This process limits the amount of sulfur in the gas and improves its quality and market value. At the same time, this results in a redistribution of sulfur in pyrolysis products such as bio-oil, improving its range of application as a source of chemical intermediates from kraft lignin.

Bleached cellulose biochars as a sustainable alternative for oilfield-produced water (OPW) treatment and environmental remediation

Eucalyptus, a renewable and fast-growing raw material widely used in the paper industry, has great potential for new applications beyond papermaking. Bleached eucalyptus pulp, traditionally used in the pulp industry, has proved to be a promising alternative for removing complex organic compounds such as naphthenic acids (NAs), often found in oil-produced water (OPW). This study aimed to optimize the production of biochars from bleached eucalyptus pulp through pyrolysis at 700, 800, and 900 °C and to correlate the resulting properties with the ability to adsorb NA at low concentrations and in acidic and alkaline media. The research explores realistic environmental scenarios where naphthenic acids may be present in dilute concentrations after initial treatments. The biochars were characterized by their micro and mesoporous structures, amorphous structures, and distinct functional groups and were evaluated in simulated effluents. Biochar B900 reached a maximum adsorption capacity of 35 mg/g at pH 4 and 25 °C, excelling in acidic environments, while at pH 8, biochar B700 showed better performance. The PVSDM model revealed that mass transfer and pore diffusion coefficients increased with increasing pyrolysis temperature. The Langmuir model was the best fit for the experimental data. The biochar produced at 900 °C had the highest specific surface area (1,041.55 m2/g) and pore volume (0.56 cm3 g−1), favoring its adsorption capacity. Although the biochar shows good initial efficiency, the progressive reduction in adsorption capacity over the cycles suggests limited reusability, highlighting the need for optimization in the regeneration process to improve its economic viability in wastewater treatment.

One Health, One Forest: Harnessing Reclaimed Wood as a Sustainable Solution

Deforestation is a multifaceted and wicked problem characterized by its complexity and resistance to straightforward solutions. The issue is driven by human activities and has severe ecological, socio-economic, and climatic consequences. Between 1990 and 2015, approximately 129 million hectares of forest were lost globally, a trend contributing to biodiversity loss, increased carbon dioxide emissions, and climate change. In Canada, deforestation due to logging significantly impacts the boreal forests, with consequences such as habitat fragmentation affecting species like the threatened boreal caribou. The Canadian logging industry aims to provide essential raw materials while fostering economic growth and employment, supplying critical resources for sawmills, planing mills, shingle mills, and pulp and paper industries. Despite economic benefits, logging, particularly clearcutting, disrupts natural forest regeneration, soil composition, and water cycles, leading to long-term ecological consequences. The One Health approach, integrating human, non-human animal, and environmental health, is proposed to address this issue sustainably. Actions like those by Forests Ontario and Evergreen focus on reforestation and urban greening, while companies like Consolidated Pallet Co. promote wood recycling. This action plan showcases the potential for community-driven solutions to reduce environmental footprints, enhance sustainability, and foster economic and social well-being.

Ecotoxicity of alkaline residue from the pulp and paper industry to soil faunal organisms

The increased production and expanding demand for cellulosic products have required companies to provide solutions for the proper disposal of generated residues without compromising soil quality. In this context, the current research aimed at evaluating the ecotoxicological impacts of dregs application in subtropical soils. The experiments were carried out with the earthworm Eisenia andrei, the springtail Folsomia candida, and the potworm Enchytraeus crypticus in two subtropical soils (Neosol and Cambisol) collected in the southern region of Brazil. The considerable differences in texture and organic matter content motivated the choosing of these soils. The reproductive rate of all organisms was influenced, with varying EC50 values depending on the soil type. However, more pronounced effects were observed for Neosol. The springtail F. candida proved to be the most sensitive to contamination (EC50 = 5.8 g kg−1 for Neosol and 48.5 g kg−1 for Cambisol), followed by the earthworm E. andrei (EC50 = 62.4 g kg−1 for Neosol and 129.5 g kg−1 for Cambisol) and the potworm E. crypticus (EC50 = 67.2 g kg−1 for Neosol and 230.4 g kg−1 for Cambisol). As a result, while dregs can be used to correct soil acidity, they have been shown to have negative effects on important organisms responsible for functions critical to maintaining ecosystem quality.

Evaluation of Commercially Available Plant-based Food Serving Disposable Crockery for Quality Standards

Biomass-based disposable crockery products are in high demand as an alternative to the plastic-based products considering negative effects of plastic-based products on environment. Biomass-based cutleries are being made from locally available different sources such as leaves, sheaths, straws and other plant fibres. A study was conducted to assess the quality of the biomass-based utensil product and provide the standard technical requirements of selected biomass-based disposable products. The plant-based utensils made from corn starch, sugarcane bagasse, areca, paper and Sal (Shorea robusta) leaves were selected for this study. The available standard methods such as International Organization for Standardization (ISO), Technical Association of the Pulp and Paper Industry (TAPPI), National Standard of the People’s Republic of China, and Bureau of Indian Standards (BIS) were adapted, with suitable modifications wherever required, for conducting the experiment. The test included measurement of dimensional specifications, grammage, moisture content, temperature resistance test, load bearing test, high heat performance test, drop test, tensile test and three point bending rig test. The plant-based utensils were classified as very strong, strong and weak based on the strength characteristics test. The utensils made from sugarcane bagasse fall in all three categories (very strong, strong and weak), whereas areca-based lies between very strong and strong while corn starch- based fall between strong and weak category. Overall, the results showed a lot of variation in strength characteristics of biomass-based disposable crockery products. The data of this study can serve as a valuable information for manufacturers and suppliers of plant-based utensils to ensure and improve product quality while maintaining the technical standards.