Paperboard Mill Research Articles

Cellulase-assisted refining in a paperboard mill: Avoided emissions from energy savings. A case study of a Finnish paperboard mill

The 2023 being on its way to be the warmest year in the 174-year global surface temperature history it is becoming more and more evident how crucial it is to break the linkage between economic growth and greenhouse gas emissions.The pulp and paper industry is highly energy intensive industry sector. It is the fourth largest industrial energy user and currently produces approximately 1.3% of global greenhouse gas emissions. While the demand for paper and paperboard products keeps rising, it is essential for the industry to find energy efficient solutions for reducing the environmental impact of the pulp and paper products. 80% of the progress in energy efficiency in Finnish paper mills is due to improved technology and more optimal operational modes. Optimizing existing processes has bigger effect on energy efficiency than closing old and starting new paper mills.Pulp refining is one of the most energy intense steps in the paperboard production, representing 15%–18% of the total energy consumption of a paper mill. The effect of a commercial cellulase enzyme product was evaluated for energy savings and avoided emissions in the refining process of a paperboard mill. Data from a paperboard line using Bleached Softwood Kraft Pulp (BSKP) from a separate pulp mill was provided by a Finnish paperboard mill containing production runs both with and without commercial cellulase product ECOPULP® R. Data was collected from the mill automation system to evaluate and compare a refining capacity restricted run and a run that was not refining capacity restricted.Analysis of the data showed a reduction of refining energy by approximately 16%–17% when the cellulase enzyme was used. This corresponds to 2 kg of CO2 emissions avoided per tonne of pulp refined when calculated using the Finnish average electricity emissions intensity in 2022. Use of the cellulase enzyme enabled the refining results that could not have been reached with the bare mechanical refining capacity of the mill.Cellulases can be efficient processing aids in pulp refining. The reduction of required mechanical refining and electrical power to run the refiners to achieve the required freeness can significantly affect the carbon footprint of the paperboard products, whereas the negative impact of emissions from enzyme production is negligible. Reduction of CO2 emissions is especially significant in the areas where the electricity mix used for the production is based heavily on fossil fuels.

Paperboard Mill Sludge Derived Nanocellulose as a Biosorbent for Hexavalent Chromium

Paperboard Mill Sludge Derived Nanocellulose as a Biosorbent for Hexavalent Chromium

Development of Drying Energy Saving Technology of Paperboard by Applying Precipitated Calcium Carbonate Made from Oyster-Shell Byproducts

In this study, we aimed to identify the possibility of the internal application of a precipitated calcium carbonate made from oyster shell byproducts (O-shell PCC) for reducing the drying energy in paperboard mills. The micro-fibrillated cellulose (MFC) was also applied to improve the strength of the paperboard containing O-shell PCC. The O-shell PCC was classified through an 80 mesh screen and then its SEM image, particle size, and zeta potential were analyzed. After the MFC was prepared by micro-grinding hardwood bleached kraft pulp (Hw-BKP), its particle size, viscosity, and fiber width were also measured. The O-shell PCC and MFC were added to the Korean old corrugated container (KOCC) stock to prepare handsheets, and their physical properties and drying energy reduction were measured to determine the effect of the O-shell PCC and MFC on the drying energy saving. The O-shell PCC was effective to improve the bulk and drying energy reduction of handsheets, but the strengths decreased. The MFC was effective in improving the strength, but more drying energy was required as the addition of MFC increased due to its hydrophilic property. In addition, the application of the PCC and MFC, which had not been used in paperboard mills, could increase the production cost. However, the reduced cost of drying energy was estimated to be more than the increased cost of PCC and MFC at the optimum dosage (6% O-shell PCC and 0.2% MFC on o.d. fiber). Therefore, it was concluded that the combination of O-shell PCC and MFC could be effective in saving drying energy in paperboard mills.

Energy Optimization in a Paper Mill Enabled by a Three-Site Energy Cooperation

Although there are opportunities to reduce electrical energy demand in unit processes of mechanical pulp-based paper and paperboard production, this may not be financially beneficial. This is generally because energy optimization opportunities connected to reduced refiner electricity demand in mechanical pulping systems also results in less steam available for the drying of the paper. As modern high consistency refiner systems produce approximately one ton of steam for each MWh of electricity when producing one ton of pulp, a reduction in electric energy demand leads to increased fuel demand in steam boilers to compensate for the steam shortage. In this study, we investigated what the financial and environmental situation would look like if we were to expand the system border from a paper mill to a larger system consisting of a mechanical pulp-based paper or paperboard mill, a district heating system with an incineration boiler and a chemical pulp mill. Mechanical pulp production has a wood to product yield of >90%, a high electric energy demand to separate woodchips to pulp and is a net producer of heat and steam while chemical pulp-based production has a wood to product yield of 50%, a low electric energy demand and is a net heat and electricity producer due to the combustion of dissolved wood polymers. The aim of this research is to create useful and robust models of how to use excess heat from certain industry sites to cover the steam shortage in other industry sites by means of utilizing and optimizing the district heating systems connecting these sites. For this purpose, we used a simulation tool which dynamically allows us to evaluate different scenarios. Our results shows that there is great potential to reduce both carbon dioxide emissions and production costs for industry sites and society by means of these tools.

Kinetic and isotherm insights of Diclofenac removal by sludge derived hydrochar

Recently, hydrothermal carbonization emerges as the most viable option for the management of solid waste with high moisture content. Sludge derived hydrochar is used as an adsorbent for emerging contaminants or micro-pollutants in the domain of sustainability. Current study demonstrates the KOH activation of hydrochar produced from paper board mill sludge and evaluates its removal potential of a Non-steroidal anti-inflammatory drug, Diclofenac from aqueous solution. The activated hydrochars exhibited porous, spherical micro-structures with higher fraction of oxygenated functional groups paving way for the efficient adsorption of Diclofenac. The effect of initial Diclofenac concentration and contact time was ascertained using adsorption kinetics and isotherms. The adsorption kinetics exhibited second-order reaction for all adsorbents indicating higher coefficient of determination (R2 > 0.9). The Diclofenac adsorption on hydrochars followed Langmuir isotherm model with the post-activated hydrochar recording a highest adsorption capacity of 37.23 mg g−1 in 40 mg L−1 initial Diclofenac concentration at 15 h equilibrium time.

Production and Characterization of Paper Board Mill ETP Sludge Derived Hydrochar

Hydrothermal Carbonization an emerging technology for the conversion of biomass into carbon rich materials called as hydrochar. In this study, the paper board mill ETP sludge has been used for the production of hydrochar. The characterization of point of zero charge, Heavy metals, proximate and ultimate constituents, structural morphology (SEM), and molecular surface functionalities (FTIR) were also analysed. The results of Hydrochar showed slightly acidic pH (6.40), EC (1.33), and the pHPZC (point of zero charge) of 7.8 and the heavy metals content were found to be below detectable limit. FTIR analysis revealed that, the produced hydrochar have oxygen containing functional groups (-OH, C-O-C, -C=O). SEM analysis has the morphological features such as spongy, fuzzy and fluffy porous network on surfaces. These results of hydrochar can be act as an active adsorbent with further activation.

Fundamental Study of the Production of Paper Ash Made from Paper Sludge II : Development of Paper Ash Application Technology to Improve the Bulk and Save Drying Energy of Paperboard

In this study, paper ash generated during the incineration process of paper sludge was applied to measure the bulk, strength, and drying energy reduction of paperboard to assess the possibility of using it as an inorganic additive in paperboard mills. Three types of paper ash were fabricated by incineration, crushed, and fractionated with three different screen sizes, and their physical properties were measured. The fabricated paper ashes were added to Korean old corrugated containers (KOCC) stock to make handsheets, and their physical properties and drying energy reduction were determined. In addition, paper ash particles classified into 200 mesh screens were surface-modified with cationic polyacrylamide (C-PAM), and the handsheets were manufactured to analyze the strength improvement effect of paperboard. The bulk and the drying energy reduction improved as the paper ashes were added into the KOCC stock, but the tensile index, compression index, and burst strength decreased. In particular, the higher the average particle size of the paper ash, the higher the bulk and the drying energy reduction, but the lower the strength. The surface modification of the paper ash with C-PAM was effective in improving the strength. Therefore, paper ash made of paper sludge collected from specialty paper mills is effective in improving the bulk and drying energy reduction of paperboard, and surface modification with C-PAM is required to prevent the deterioration of paper strength.

Hydroponic phytoremediation of paperboard mill wastewater by using vetiver (Chrysopogon zizanioides)

Floating hydroponic system (FHS) is a potential and cost-effective technique for wastewater treatment. Vetiver (Chrysopogon zizanioides) is a more efficacious material for phytoremediation due to its physiological and morphological properties. A pilot-scale investigation on phytoremediation potential of FHS was carried out using Vetiver grass (Chrysopogon zizanioides) along with aeration on treated (TE) and raw effluents (RE) from paper board mill industry. Among the treatments, the vetiver hydroponic system with aeration had the highest treatment efficiency in the remediation of treated paper board mill effluent. The outcomes of the study exhibited a significant reduction in electrical conductivity (39.39%), total soluble salts (81.19%), and total dissolved solids (56.19%). The decline in Biological oxygen demand (55.68%) and chemical oxygen demand (58.01%) was evident at the end of the study period. The decrease in nutrients like total nitrogen (59.24%), phosphorus (47.78%), potassium (54.64%) was attributed to the growth of the vetiver grass. The lead concentration was dropped by 65.63% to 0.09 mg L−1 under the regime's permissible limits, and cadmium concentration decreased by 64.29%. From these results, the hydroponically grown vetiver treatment system combined with aeration poses a promising future for developing a sustainable, cost-effective methodology for pollutant detoxification in paperboard mill wastewater.

Effect of fertigation through treated paperboard mill effluent on soil microbial properties and growth of banana

A field experiment was conducted at agricultural farm belonging to ITC paperboard mill situated at Thekkampatty Village, Coimbatore District to evaluate the influence of fertigation through treated board mill effluent on microbial property of soil and the growth of banana. From the study it was observed that biometric observations viz., the plant height, pseudostem girth, number of leaves, number of suckers and leaf area increased due to fertigation of effluent with 75 per cent NK over basin application of the effluent and farmer’s practice. Combined addition of fly ash + biocompost + green manure recorded more number of leaves. Application of green manure along with fly ash and biocompost under effluent fertigation with 75 per cent NK improved, soil biological properties (soil bacterial, fungal, actinomycetes population and soil enzymatic activity (urease, amylase, phosphatase, invertase, catalase, peroxide activity). The above findings indicated that the treated effluent from paperboard mill could possibly be used through drip irrigation along with fertigation to banana crop without any adverse effect on soil properties and crop growth.

Odor Analysis of Paperboard Mills

Odor Analysis of Paperboard Mills

Evaluation of Yield and Quality Attributes of Grafted Brinjal under Treated Paperboard Mill Effluent Irrigation and Sludge Application

Field experiment was conducted to assess the impact of paperboard mill sludge compost and treated paperboard mill effluent irrigation on growth and yield of grafted brinjal. Among the different treatment combinations, application of phosphorus enriched ETP sludge compost at 5 t ha-1 along with treated effluent through drip irrigation and recommended level of NPK (200:150:100 kg NPK ha-1) resulted the highest brinjal yield of 42.7 t ha-1. There were no adverse effects on soil properties due to sludge compost application and treated effluent irrigation. Quality attributes of the fruits which include anthocyanin content, total phenol content, ascorbic acid content, titrable acidity and protein content were not affected due to the composted sludge application along with treated effluent irrigation. Thus, the treated effluent and the composted sludge which complies with the state pollution control board norms can be used as a viable alternative source of irrigation and nutrients for grafted brinjal cultivation without adversely affecting on crop quality.

Impact of treated papermill effluent on yield and quality of Bhendi

An attempt has been made to use the treated paperboard mill effluent and well water with STCR recommended NPK, MLSS (Mixed Liquor Suspended Solids) and pressmud compost as nutrient source for cultivating Bhendi crop to assess their impact on yield and fruit quality. Application of MLSS, Pressmud compost had increased the available nutrients (N, P, K) and organic carbon content in the soil. The treatment combination of 50% STCR recommended NPK + 50% MLSS (Mixed Liquor Suspended Solids) + effluent irrigation performed better compared to other treatments. The experimental results revealed that yield of Bhendi under treated effluent irrigation was higher than well water irrigation. The yield increase was recorded as 31.20 percent over the control (100% STCR NPK + well water). The quality parameters viz., crude fibre and total protein were higher under effluent irrigation.

Identification of Foulants on Polyethersulfone Membranes Used to Remove Colloids and Dissolved Matter from Paper Mill Treated Effluent

In this study, membrane fouling caused by paperboard mill treated effluent (PMTE) was investigated based on a dead-end ultrafiltration (UF) pilot-scale study. The membranes employed were commercial hydrophobic UF membranes made of polyethersulfone (PES) with a molecular weight cut-off of 10 kDa, 50 kDa, and 100 kDa. Membrane fouling mechanism during dead-end filtration, chemical analysis, field emission scanning electron microscopy (FESEM), energy-dispersive spectrophotometry (EDS), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and 3D fluorescence excitation–emission matrix (3DEEM) analysis were applied to understand which fraction of the dissolved and colloidal substances (DCS) caused the membrane fouling. The results indicated that the phenomenon controlling fouling mechanism tended to be cake layer formation (R2 ≥ 0.98) for all membranes tested. The 3DEEM results indicate that the majority of the organic foulants with fluorescence characteristics on the membrane were colloidal proteins (protein-like substances I+II) and macromolecular proteins (soluble microbial products, SMP-like substances). In addition, polysaccharide (cellulosic species), fatty and resin acid substances were identified on the fouled membrane by the ATR–FTIR analysis and play an important role in membrane fouling. In addition, the FESEM and EDS analyses indicate that the presence of inorganic foulants on the membrane surfaces, such as metal ions and especially Ca2+, can accelerate membrane fouling, whereas Mg and Si are linked to reversible fouling.

Preparation and Characterization of Optimized Hydrochar from Paper Board Mill Sludge

The amount of Paper Board Mill Effluent Treatment Plant Sludge (PBM-ETPS) dumped from paper mills are huge and its conversion into hydrochar for the purpose of energy has broad prospects. This study investigated the optimum conditions for the production of PBM-ETPS derived hydrochar (PBM-ETPSH) through Reponse Surface Methodology (RSM) for more surface area and pore volume with minimal hydrogen to carbon (H/C) and oxygen to carbon (O/C) ratios. The PBM-ETPSH had higher heating value (HHV) of 18.39 MJ kg−1 with fixed carbon percentage of 15.6. Our results showed a reduction in H/C (35.05%) and O/C (43.7%) ratios confirming the coalification of optimized PBM-ETPSH. Thermogravimetric investigations of blending PBM-ETPSH with coal in 1:1 ratio increased its HHV to 22.25 MJ kg−1 making it suitable as an energy alternative for paper mills.

Paperboard mill wastewater treatment via combined dark and LED-mediated fermentation in the absence of external chemical addition

Paperboard mill wastewater (PMWW) was treated using two subsequent dark and photo up-flow intermitted stirring tank reactors (UISTRs) under different hydraulic retention times (HRTs) without external chemical use. HRT of 12 h revealed the maximum overall H2 productivity of 1394.1(±70.6) mL/L/d with contents of 48.9(±2.5) and 47.4(±1.4)% for dark- and photo-processes, respectively. Overall substrate removal efficiency (SDE) of 58.9(±4.5)% was registered at HRT o 12 h. High H2 productivity was ascribed to fermentation type occurred at dark reactor, since acetate and butyrate accounted for 70.9% of volatile fatty acids. Besides, pH and carbon to nitrogen ratio of dark reactor’s effluent at HRT = 12 h were 5.5(±0.1) and 30.0(±2.5), respectively which are the optimum levels for photo fermentation process. Moreover, energetic and economic analyses emphasized on the superiority of 12 h-HRT, where net gain energy, daily saving and payback period accounted for 1319.5 kWh/d, 148.7 $/d and 9.8 years, respectively.

Slagging and fouling characteristics during co-combustion of Scots pine bark with low-temperature dried pulp and paper mill chemical sludge

This paper shows how chemical sludge (CS) generated during wastewater treatment at a paperboard mill can be quickly dried at low-temperature and employed in bark-fired boilers to reduce slagging and corrosion problems. By using a cyclone-dryer operated at an inlet-air velocity of 110 m/s and a temperature of 90 °C, the dry-matter content of CS was increased from approximately 19 to 82%. The residence time of CS inside the cyclone was approximately 2 s when using the inlet-air velocity mentioned above. Disaggregation of the feedstock caused by collisions with the cyclone wall and between particles played a crucial role in enhancing the efficiency of heat and mass transfer. Three co-pelletized mixtures of Scots pine bark (SPB) and dried-CS were combusted in a 40 kW fixed-bed burner. Flue gas analysis was performed with a gas analyser. Coarse and fine ash were analysed by SEM-EDS and XRD. NOx and SO2 emissions increased with increasing amount of CS in the mixtures. Mono-combustion of SPB resulted in a large quantity of slag (i.e., molten ash) with a high degree of sintering (i.e., hardness of the slag), and ash deposits formed on heat transfer surfaces were rich in K2SO4 and KCl. Mixtures of SPB and CS were less prone to slagging, and the amount of alkali chloride in the deposits was reduced in favour of alkali sulphate formation.

Laboratory method for determining the source of brightness loss at a southern United States bleached paperboard mill

Bleached pulp is known to lose some brightness between the end of the bleach plant and the paper machine reel. An ISO brightness drop of 1–3 points is often experienced. There are many reasons for the brightness loss; however, the usual suspects tend to be water quality, metallurgy, and process chemicals. One bleached paperboard mill in the southern United States had been experiencing brightness losses in the 6–8 point range for several years. A systematic study was conducted to determine the potential sources for this brightness loss. A laboratory simulation technique was developed to demonstrate the potential causes for the brightness loss along the process.

Establishing Vetiver Based Treatment System for Treating the Wastewater from Paperboard Mill

Establishing Vetiver Based Treatment System for Treating the Wastewater from Paperboard Mill

Bio-composites for the sorption of copper from aqueous solution: A comparative study

Metal cleaning and plating baths, pulp, paper board mills, printed circuit board and wood pulp production, fertilizer industry etc. are releasing copper into the environment and seriously affecting the quality of drinking water. Even minute quantity of copper (1.3 ppm) in water is detrimental to biota. Therefore, abundantly available poultry and agricultural wastes are tested as adsorbents for the removal of copper leading to sustainable management of wastes and improving the quality of water. Sorption capacities of chitosan-Gallus domesticus eggshell, chitosan-Dromaius novaehollandiae eggshell (CH-GDES, CH-DNES) and chitosan-Dromaius novaehollandiae feather (CH-DNF) composites were first evaluated for copper removal from aqueous solution by ‘one variable at a time’ method, and further experiments were carried out by a three level full factorial design of Response Surface Methodology (RSM). The percent removal of copper by the composites increased with the increase in contact time and the kinetics best fitted to the pseudo - second order model. The optimum pH of the aqueous solution was found to be 6 for the removal of copper for all the three composites. The experimental data of initial metal ion concentration was fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption isotherm models, and the better suited is Langmuir's isotherm model. Chitosan-Gallus domesticus eggshell composite showed the highest metal uptake potential of copper (qmax 56.49 mg/g). Thermodynamically, copper adsorption onto the bio-composites is inferred as spontaneous, irreversible and endothermic in nature. Characterization of the adsorbents by SEM-EDS, FTIR, XRD and BET, before and after adsorption of copper, revealed that the sorption is due to the mechanisms of chemisorption, ion exchange and/or complexation. The adsorbent pads/filters made of natural renewable biopolymer composites like CH-GDES/CH-DNES/CH-DNF, can be placed at the source to prevent bulk water pollution with copper and maintain the concentration well below the permissible limits in the ground water.

Effect of starvation period on microbial community producing hydrogen from paperboard mill wastewater using anaerobic baffled reactor

ABSTRACTThe aim of this study is to highlight the robustness and potentials of the anaerobic baffled reactor (ABR) configuration on keeping the microbial richness and diversity after starvation period of 7 days. The module at steady state operating conditions provided an average volumetric hydrogen production (VHP) of 0.2 ± 0.08 and 0.423 ± 0.5 l/d in the 1st and last compartment (C4). The VHP was gradually decreased from 0.2 to 0.003 l/d and from 0.423 to 0.1 l/d in compartments (C1 and C4) respectively during feed less period. However, the VHP was substantially increased up to 0.035 and 0.152 l/d in 1st (C1) and fourth compartment (C4) within 24 h, after reoperation of the ABR. Moreover, the H2 producers of Clostridiaceae, Ruminococcaceae, and Enterobacteriaceae families were dominant in the reactor after reoperation process. Quantitative polymerase chain reaction and next-generation sequencing methods results revealed that the microbial community structure was mainly composed of Proteobacteria, Firmicutes, Chloroflexi, Bacteroidetes, Planctomycetes, and Actinobacteria. The results showed the unique properties of the ABR configuration for keeping the microbial richness and diversity during feed less period.