Canadian Pulp Research Articles

Metagenomes and metagenome assembled genomes from anaerobic digesters at three Canadian pulp and paper mills.

We present a dataset of six metagenomes and 323 metagenome assembled genomes (MAGs) describing the microbial community of anaerobic digesters at three Canadian pulp and paper mills. Our objective was to assess the coding potential of the microbial community and obtain draft genomes of key organisms in the digesters.

Estimating lags in a kraft mill.

In pulp mills, lags obscure the effect of upstream operations on downstream measurements. Here, we estimate lags in a Canadian pulp mill using autoregressive exogenous (ARX) models. First, we show that ARX models can approximate lags in a process simulation that resembles the liquor storage tanks in pulp mills, a major source of lag inthe kraft recovery cycle. Then, we use ARX models to estimate the lagged effect of a change in species pulped on as-fired liquor heating value, viscosity, and boiling point rise. Additionally, we compare the predictions of the ARX models to autoregressive (AR) models and a persistence model. The estimated lags between a change in species and heating value (49 h) and boiling point rise (41 h) agree with a detailed simulation of the mill and are close to estimated hydraulic residence times, suggesting that the liquor tanks exhibit imperfect mixing. A lagged effect of species change on viscosity could not be identified. ARX and AR models produce similar predictions that are slightly better than those of a persistence model. Finally, we show that process measurements upstream of units characterized by large residence times will likely provide little benefit to prediction accuracy.

A multi-level production-inventory-distribution system under mixed make to stock, make to order, and vendor managed inventory strategies: An application in the pulp and paper industry

In today's competitive environment, most companies tend to adopt a hybrid manufacturing strategy to provide more reliable services to a wide range of customers. Based on a real-world case study, we investigate a customer-wise production-inventory-distribution system in a multi-level supply chain. Within this system, at a tactical planning level, the decision concerning the production strategies including make to stock (MTS), make to order (MTO), or vendor managed inventory (VMI) strategy, to choose for each customer is made, and then at the operational planning level, the production, inventory, and distribution activities are coordinated according to the strategy assigned to the customers. The objective is to optimize the total cost while the VMI customers are timely satisfied and the target service level for MTO customers is respected. Furthermore, the purchase acceptance rate for MTS customers can be controlled to enhance capacity utilization. We develop a rolling horizon planning approach to deal with the dynamics of customers' demands under different forecasting scenarios. We perform numerical experiments under both static and rolling horizons based on adapted data from a real-world application from a Canadian pulp and paper industry. The results reveal that customers placing smaller orders are classified within the VMI strategy to mitigate potential delays. Conversely, MTS customers are predominantly characterized by larger order quantities. A sensitivity analysis of key problem parameters demonstrates that the backorder cost for MTO customers can effectively influence the strategy allocation. Moreover, our results underscore the notable influence of sales prices on the distribution of customers among strategies.

Model and solution approach to coordinate production-inventory strategies considering nonlinear price-sensitive demand: application to Canadian pulp and paper industry

This study addresses a practical problem within a multi-level supply chain where a wide range of customers can be served through different strategies such as make-to-stock, make-to-order, or vendor-managed inventory. The customer demand is stochastic, and sensitive to pricing associated with different production-inventory strategies. We propose a two-stage stochastic mixed-integer non-linear programming model. In the first stage, decisions are made regarding the selection of production-inventory strategies and pricing to maximise the expected profit. The second stage involves decisions related to production, inventory, and distribution, which are used to evaluate the first-stage decisions under various scenarios with different levels of accuracy. To solve the model, a metaheuristic approach based on the Simulated Annealing algorithm is developed. To showcase the practical applicability of our model and solution approach, we use a real case study in a Canadian pulp and paper supply chain. The results revealed that both the production-inventory strategy assigned to customers and the sales price underwent changes across scenarios. Furthermore, we demonstrated that by implementing the SA algorithm, we could improve the initial profit by up to 1.43% through slight adjustments in the sales price and assigned strategies for customers.

Polygon generation and video-to-video translation for time-series prediction

This paper proposes an innovative method for time-series prediction in energy-intensive industrial systems characterized by highly dynamic non-linear operations. The proposed method can capture the true distributions of the inputs and outputs of such systems and map these distributions using polygon generation and video-to-video translation techniques. More specifically, the time-series data are represented as polygon streams (videos), then the video-to-video translation is used to transform the input polygon streams into the output ones. This transformation is tuned based on a model trustworthiness metric for optimal video synthesis. Finally, an image processing procedure is used for mapping the output polygon streams back to time-series outputs. The proposed method is based on cycle-consistent generative adversarial networks as an unsupervised approach. This does not need the heavy involvement of the human expert who devotes much effort to labeling the complex industrial data. The performance of the proposed method was validated successfully using a challenging industrial dataset collected from a complex heat exchanger network in a Canadian pulp mill. The results obtained using the proposed method demonstrate better performance than other comparable time-series prediction models. This allows process operators to accurately monitor process key performance indicators (KPIs) and to achieve a more energy-efficient operation.

Energy efficiency as a critical resource to achieve carbon neutrality in the pulp and paper sector

The urgent challenge of reducing industrial greenhouse gas emissions has created a growing demand for a more comprehensive understanding of how various technology options can contribute to achieving carbon neutrality. Energy efficiency has long been regarded as a key pathway in this context, but the volume and diversity of efficiency options has resulted in an unclear understanding of their combined impacts. In this study, we present a novel technology-explicit method to estimate the overall abatement potential associated with a comprehensive suite of 115 energy efficiency technologies spanning all relevant sector processes and energy types. By applying our flexible analysis framework to a case study of the Canadian pulp and paper sector, we demonstrate that energy efficiency could be the single largest contributor to achieving a carbon-neutral target for the sector. We find that efficiency can reduce emissions by 4.92 MtCO 2 e/yr (66%) relative to business-as-usual by 2050 at a weighted average abatement cost of -$162/tCO 2 e when accounting for capital, operating, maintenance, and energy costs. Abatement at the energy system-wide level is even larger, reaching 6.67 MtCO 2 e in 2050 when accounting for upstream effects. Adoption of the full suite of efficiency measures could materially improve the competitiveness of the sector by reducing energy and carbon costs. On the whole, our results suggest that proven energy efficiency technologies could be the primary element of a credible low-cost pathway towards achieving a target of carbon neutrality for the pulp and paper sector.

Development of technology-explicit energy saving bandwidths: A case study for the pulp and paper sector

Industrial energy efficiency has long been recognized as a critical tool for energy management and emissions reduction and is increasingly considered to be an energy resource in its own right. However, the complexity of most industrial sectors creates barriers for modellers, companies, and policymakers in understanding and achieving the overall potential for efficiency-driven energy savings. To address this gap, we have developed a novel method that combines disaggregated bottom-up sector energy modelling with analysis of a comprehensive set of technology-explicit energy efficiency measures. This approach overcomes the deficiencies of top-down analyses and better represents the complexities of multi-measure efficiency investments compared to piecewise studies of individual measures. In this study, we demonstrated application of our method to the case of the Canadian pulp and paper sector. Our analysis shows that the sector can reduce its natural gas and electricity use by 95% and 41%, respectively, by adopting economical efficiency measures. This equates to 71 PJ of natural gas and 44 PJ of electricity saved annually and would result in cost savings of $81 per tonne of output sector-wide. Notably, we find that efficiency and fuel switching have the technical potential to reduce natural gas consumption by 98% across the sector. Taken together, the results provide quantitative evidence that energy efficiency is an underestimated resource for cost-effective energy savings in the Canadian pulp and paper sector. Our analysis framework can be applied to any industrial sector in any region to provide insights regarding energy conservation strategies and policy design.

International trade standards and competitiveness of the chemical wood pulp and conifer sawn wood sectors do Brazil and Chile front of major world exporters

Given the importance that the forestry sector plays in the economy of several countries and considering the magnitude of world demand, it is understood that the participation of the forestry-based sector in the market is below its potential. The main objective of this research was to analyze the competitiveness of Brazil and Chile in the conifer sawn wood (CSW) and Chemical Wood Pulp (CWP) international market, through revealed symmetric comparative advantages (RSCA) and volume (in tons) exported compared to the world's largest exporters of these products. Brazil and Chile were chosen because they are the two main producers and exporters of these products in Latin America. Furthermore, linear regression analysis techniques were used to explain the factors that supported this competitiveness. The results of the RSCA index showed that for conifer sawn wood there are different patterns of competitiveness among the analyzed countries. For the CWP sector, Brazil is the world's leading exporter, and the RSCA indices showed that Brazil with high dynamism and Chile with lower competitiveness in the CWP sector. The results of the regression analysis to assess competitiveness via exported volume for both conifer sawn wood and CWP proved inconclusive for Chile. In relation to Brazil, the results for the exported volume of wood suggest a dependence on the US interest rate. We thus conclude that the results were probably affected by the volatility of the data analyzed from countries or sectors for which there are factors other than those considered in this study. Furthermore, Canadian pulp exports are influenced by the Brazilian price, not the other way around.

Ash properties relevance to beneficial uses

Despite being a wood-derived biomaterial, wood ash generated by Canadian pulp paper mills (PPM) is generally landfilled. This is mainly because of the heterogeneous nature of ash, variations in ash quality and differences in the requirement of ash applications. Unlike limited past work on ash analysis for environmental compliance purposes for specific mills, a comprehensive database of ash quality for the PPM has been developed. Samples of three ash streams, bottom ash (BA), multiclone ash and electrostatic precipitator (ESP) ash, were collected. They were analyzed for physical, chemical and engineering properties of relevance to potential ash uses in areas such as the construction industry, compost production, soil amendment and waste stabilization/ solidification. Results show that the ash quality varied widely from one mill to another. Even within a mill individual ash streams varied substantially in properties. For example, the unburned carbon, a unique parameter for wood ash, in multiclone ash could be over twice the amount in the ESP ash. It is suggested that the traditional definition of fly ash (FA) could be refined to multiclone ash and ESP (or baghouse) ash thereby promoting the source segregation concept for the various ash streams produced at a mill. It is believed that the ash segregation approach, whereby ash sub-streams are kept separate to preserve their quality for specific uses, will minimize heterogeneity and quality variations of ash. This study will not only help divert wood ash away from landfills in favour of beneficial applications but also reduce carbon footprint of a mill.

Integrated forest biorefinery network design under demand uncertainty: a case study on canadian pulp & paper industry

Transforming Pulp and Paper (P&P) mills into Integrated Forest Biorefineries (IFBR) is a prominent solution to save Canadian P&P industry that has been facing decline of conventional paper demand. We propose a comprehensive decision model for the design of IFBR value chains by taking the uncertain demand of bioproducts into consideration. In particular, we propose a multi-stage stochastic programming model to obtain the optimal investment plan over a long-term planning horizon in the presence of various market trends. We also develop a Monte-Carlo simulation platform to validate the proposed model and to compare its performance with alternative decision models. The model is applied to a realistic case study inspired from P&P companies in Canada, where the value of incorporating the dynamic nature of uncertain demand has been estimated. Further, we elaborate on the value of considering flexibility in terms of adjusting the investment plan in response to changes in the demand. Our results indicate that the demand for bioproducts has a substantial impact on the profitability of the IFBR. We also demonstrated the significant value of explicitly incorporating the uncertainty in IFBR network design as well as adapting the investment plan to the changes in the demand.

Screening of two freshwater green microalgae in pulp and paper mill wastewater effluents in Nova Scotia, Canada.

In recent years, the use of microalgae as feedstock for many marketable products, such as animal/aqua feeds, bioplastics and fertilizers, has gained renewed interest due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrient content. An algal biorefinery at an industrial site has the potential to sustainably and profitably convert carbon dioxide emissions into microalgal biomass and concomitantly reduce nitrogen and phosphorus from wastewaters. Industrial wastewaters are a potential alternative to traditional media used for large-scale microalgal cultivation. Pulp and paper mills are major consumers of water resources and discharge a huge amount of water to nearby lakes or rivers. This study investigated whether pulp and paper mill waste water is suitable for microalgal cultivation with the aim of achieving significant biomass production. Six different process waters from one Canadian pulp and paper mill were tested with two freshwater green microalgae. All of these waters were unable to support growth of microalgae due to inadequate nutrient concentrations, colour, turbidity and possible toxicity issues.

Seafloor and sediment characteristics of pulp mill waste discharges in the 20th century: Framework data for Boat Harbour, Nova Scotia, remediation projects and for baseline surveys of new pulp waste outfall installations in Northumberland Strait

During the 20th century, contamination of marine environments by Canadian pulp and paper mill effluent (PPE) resulted in the imposition of federal government regulations in 1971 that were revised and strengthened in 1992. This report reviews seafloor sediment features for three marine settings (intertidal, subtidal and prodelta) arising from 20th century PPE discharges from four pulp and paper mills, one located near New Richmond, Quebec, and three situated along the lower reaches of the Saguenay River, Quebec. The four mills began operations between 1965 and the early 1900’s. Observations of their proximal and distal sediment and Foraminifera characteristics in relation to PPE discharge outfalls offer guidance for the remediation of potentially toxic, multi-decadal waste accumulations in several lagoons of Boat Harbour, Nova Scotia. Seafloor environmental data discussed for a fifth mill’s subtidal outfall, located on the eastern shore of Canso Strait, may be particularly germane for selecting the site and baseline environmental survey criteria for a new PPE submarine outfall that has been proposed (presently rejected) by Northern Pulp Company for the Caribou Harbour area of the Northumberland Strait coast, in the event that the currently closed mill is permitted to be reactivated in the future. Keywords: effluent, environmental effects, organic matter, pulp mill waste, sediments

Multivariate data analysis of full-scale sludge dewatering

A multivariate data analysis (MVDA) was conducted to identify operating parameters that affect the sludge dewatering efficiency in a Canadian pulp and paper mill. The sludge is a mixture of waste activated sludge (WAS) and three different types of primary sludge. The dewatering efficiency was defined by three target parameters: the cake solids content after dewatering, the solids capture efficiency, and the costs of dewatering aids (chemicals) used per ton of dewatered sludge solids. The results show that the most influential parameters affecting the dewatering efficiency are 1) the type and amount of primary sludge added to the sludge mix, 2) the operating parameters of the dewatering equipment and 3) the sludge solids throughput. A high proportion of fiber-rich primary sludge in the sludge mix substantially enhances dewaterability. Operating the screw press at a low torque and/or at a high screw press speed lowers the dewatering performance. The pH adjustment of the sludge prior to dewatering also significantly affects dewaterability. The effectiveness of the dewatering aids decreases notably when the pH is not within the target range. Besides the processes in the dewatering plant, the activated sludge process and the associated amount and quality of the WAS also affect the dewaterability of the sludge mix. In particular, the dewatering efficiency seems to be seasonal. The higher temperature during the summer produces less WAS, and thus increasing the proportion of primary sludge in the sludge mix and improving dewaterability. Also, WAS with high microbial activity and firm flocs, as well as a low sludge volume index enhances dewaterability.

Survival of the cleanest? Evidence from a plant-level analysis of pollutant emissions in Canadian pulp and paper industry, 2005–2013

We capitalize on access to plant-level data in examining the changes in emissions of biochemical oxygen demand (BOD), total suspended solids (TSS), and greenhouse gas (GHG) for a set of Canadian pulp and paper mills from 2005 to 2013. In particular, we investigate the roles played by changes in output, emission intensity, allocation of production among surviving plants, and plant closures. Output change is the main factor and improvement of emission intensity by surviving plants—the so-called technique effect—brings a small, yet positive contribution. However, there are no indications that market operations determining plant output and plant survival lead to lower emissions.

Teaching Case. PF Integrated: Developing and Experimenting Competencies in Sustainability Accounting

ABSTRACTThis teaching case presents the struggles of PF Integrated, a fictional Canadian pulp and paper and lumber company facing mounting socio-environmental stakeholder expectations within a difficult economic context. It intends to engage accounting students in business sustainability issues and opportunities and to familiarise them with the role they can play in helping organisations transitioning toward a more sustainable business approach. Students are invited to use different socio-environmental accounting tools, integrate socio-environmental factors and stakeholder considerations in decision making and adopt an integrated perspective on the strategy and management of an organisation. The teaching note supports this endeavour by proposing three teaching plans organised around different areas of accounting (strategy and eco-control; reporting and governance; impacts on performance), which can be tailored to the instructor’s pedagogical objectives. The broad coverage of accounting issues offered by the case makes it interesting to deconstruct to cover one specific issue at a time in order to develop the students’ technical skills, or to use comprehensively for a more global study of sustainable organisational management to develop the students’ reflective thinking and integration abilities.

Dewatering of pulp and paper mill biosludge and primary sludge

Dewatering and handling of pulp and paper mill sludge is challenging and often comprises more than half of the overall wastewater treatment costs at a mill. Primary sludge is usually more dewaterable than biosludge (waste activated sludge), and the ratio between both types of sludge largely determines the dewaterability of the sludge mix. This study has quantified the benefits of adding primary sludge to biosludge to enhance the dewaterability in terms of cake solids and filtrate/pressate solids content. Furthermore, the effects of the particle size distribution and the monovalent to divalent cation ratio of the various types of sludge were investigated. Biosludge and three types of primary sludge from a Canadian pulp and paper mill were mixed at various ratios and tested for dewaterability using a Crown Press®, a bench-scale device which simulates industrial belt press dewatering. Results show that after addition of primary sludge at up to 40% mass proportion (dry solids basis) the dewatered cake solids content increased substantially, from 10.4% to 18.7–19.9%, depending on the type of primary sludge added. Further addition of primary sludge led to comparably only small improvements. Primary sludge addition also resulted in decreased total suspended solids (TSS) concentrations in the combined gravity filtrate / Crown Press pressate. Primary sludge content of only 10% in the sludge mix was sufficient to decrease the TSS concentration from 1.8 g/L to 0.2 – 0.4 g/L. The study shows that only less than half of the sludge mix needs to consist of primary sludge, in order to achieve adequate dewaterability. This opens up the possibility of retaining more primary fiber within the pulping process, without compromising downstream sludge dewatering.

Sustainability assessment of integrated forest biorefinery implemented in Canadian pulp and paper mills

To overcome declining markets and low-cost competition, the integrated forest biorefinery (IFBR) business model has received a lot of attention from the pulp and paper (P&P) sector. This article deals with sustainability assessment of IFBR implemented in P&P mills for bioenergy production. The objective is to develop a mathematically-based approach, for decision makers within the forest sector, that aims to optimize the sustainability of the IFBR value creation network. A multi-objective optimization model, applied to a Canadian case study and integrating environmental life cycle assessment (LCA), is developed. The life cycle inventory is performed for the whole system. The objective functions consist in minimizing greenhouse gas emissions and maximizing the financial value of the IFBR over a long-term planning horizon, while optimizing the existing P&P activity. Different economic and environmental indicators are introduced to compare Pareto optimal investment roadmaps. The proposed model leads to a decision support tool for the transformation of P&P companies by planning sustainable bioenergy investment implementation. Furthermore, this model may assist decision makers in emissions planning and reporting according to related regulations requirements. The obtained results show that the IFBR allows the P&P industry to diversify its portfolio and generate new revenues, while contributing substantially to emission reduction efforts in Canada and producing clean and renewable energy. However, government support will be needed to perform a successful business plan.

Ultrasonic pretreatment effects on the bio-oil yield of a laboratory-scale slow wood pyrolysis

Research on biomass conversion into energy through pyrolysis has emerged in the past several years. Pyrolysis is believed to have a real future for green-fuel production and as the means of the revitalization of the Canadian pulp and paper industry. As pyrolysis has recently been successfully optimized through the use of heterogeneous catalysts, attention has been drawn to ultrasound for its ability to cleave lignocellulosic bonds. In this study, we investigated the use of ultrasound techniques as a pretreatment for biomass before wood pyrolysis with respect to bio-oil yields. Different conditions in terms of frequency (40, 68 and 170kHz), time (0.5, 1 and 1.5h) and power (125, 250, 500 and 1000W) were explored to include the primary action mechanisms of ultrasound: mechanical and sonochemical effects. The combination of using 40kHz and 170kHz frequencies in a sequence of 0.5h at 170kHz and 1.5h at 40kHz and a power of 1000W has been demonstrated to be the best, achieving a 12% increase in bio-oil yield compared to untreated wood. However, contrary to what was thought at first, the best energy efficiency was obtained at low power (125W) with a Watt per percentage of extra oil produced ratio of 47. Therefore, depending on the final production goal, the ultrasonic conditions could be adjusted accordingly. Finally, the chemical analysis of the oils by GC indicated no influence of the pretreatment on the final composition of the recovered oils.

The Canada–United States productivity puzzle: regional evidence of the pulp and paper industry, 1971–2005

We analyze the total factor productivity (TFP) of the pulp and paper industry in three Canadian provinces (British Columbia, Ontario, and Quebec) and in three United States (US) states that are contiguously located south of the border (Washington, Illinois, and Maine) over the period of 1971 to 2005. We find that the industry in the three Canadian provinces had much higher TFP growth rates in the era following the Free-Trade Agreement (FTA) signed in 1988. In terms of productivity level, this relative TFP surge allowed the industry in Ontario and British Columbia to move ahead of Illinois and Washington, respectively; however, Quebec trailed further Maine, which is the overall leader in the sample. Our results in this particular case reveal that the Canadian pulp and paper industry did not contribute to the overall Canada–US productivity gap.

Exploring our Past Through the Woodlands Section of the Canadian Pulp and Paper Association

Exploring our Past Through the Woodlands Section of the Canadian Pulp and Paper Association