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The main objective of this study was to develop models for accurate prediction of municipal solid waste (MSW) generation and diversion based on demographic and socio-economic variables, with planned application of generating Canada-wide MSW inventories. Models were generated by mapping residential MSW quantities with socio-economic and demographic parameters of 220 municipalities in the province of Ontario, Canada. Two machine learning algorithms, namely decision trees and neural networks, were applied to build the models. Socio-economic variables were derived from Canadian Census data at regional and municipal levels. A data pre-processing and integration framework was developed in Matlab® computing software to generate datasets with sufficient data quantity and quality for modeling. Results showed that machine learning algorithms can be successfully used to generate waste models with good prediction performance. Neural network models had the best performance, describing 72% of variation in the data. The approach proposed in this study demonstrates the feasibility of creating tools that helps in regional waste planning by means of sourcing, pre-processing, integrating and modeling of publically available data from various sources. [ABSTRACT FROM AUTHOR]

• Cost and carbon footprint of transport fuel production from CO 2 were investigated. • Pathways based on bicarbonate electrolysis and RWGS technologies were evaluated. • Large differences in cost of diesel production were not observed. • Carbon footprint of both pathways were lower compared to conventional diesel. • Bicarbonate electrolysis technology offers further opportunities to reduce GHG emissions. Early evaluation of carbon capture and utilization (CCU) pathways in terms of cost and emission reductions is critical in guiding future R&D and commercialization. However, such evaluation is challenging due to varying technology readiness levels (TRL) of pathways, unavailability of cost and emission data for new technologies and uncertainty of performance parameters of lab scale technologies. In this study, we propose a standardized methodology that allow comparing synthetic fuel production pathways based on early stage lab scale CO 2 electrolysis technologies with mature CCU technologies and incumbent technologies. This methodology provides guidelines for defining pathways, modeling and cost and carbon footprint (CF) assessment supported by a bottom-up framework to scale- up the costs and CF of lab scale technologies. We apply the developed methodology to evaluate Fischer-Tropsh synthesis (FTS) fuel production pathways based on bicarbonate electrolysis, a novel early stage CO 2 electroreduction technology with integrated CO 2 capture, and reverse water gas shift (RWGS) reaction, a mature thermocatalytic CO 2 conversion technology. The cost of diesel fuel production using RWGS and bicarbonate electrolysis pathways were 1.7 $/L and 1.5 $/L, respectively, which is more than 140% of current cost of diesel. Nevertheless, both pathways were able to achieve significant emissions reductions with bicarbonate electrolysis reducing 90% and RWGS reducing at 70% compared to conventional diesel. Based on the uncertainties of calculated cost, neither pathway is more economically competitive than the other. However bicarbonate electrolysis pathway offer more opportunities for emission reduction as most of its energy demand can be provided by renewable electricity. RWGS pathway with relatively higher thermal energy demand will need to rely on high level of energy recovery and integration to achieve similar emission reductions. [ABSTRACT FROM AUTHOR]

The effects of mixing hydrodynamics on the particle and filtration properties of precipitated lignin from black liquor has been investigated. The hydrodynamics were varied in terms of turbulent shear rate and impeller flow pattern in the stirred tank. The precipitated lignin flocs were characterized in terms of particle size, size distribution, and particle shape. Our findings showed that the effect of hydrodynamics on the size and shape of primary lignin particles were negligible. However, the aggregation of primary particles into lignin flocs were affected by the hydrodynamics of the stirred tank. The size distribution and shape of the final lignin flocs could be controlled mainly through the manipulation of turbulent shear rate. Lignin flocs with higher compactness and size showed better filtration and washing properties. Optimal hydrodynamic conditions led to production of lignin with good filtration and washing properties at 1.83E + 09 m/kg specific filtration resistance, 243 kg/h m 2 lignin filtration rate, generating high purity lignin at 0.09% ash content. The reproducibility of the findings was validated using three other black liquor samples. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) is an attractive technology for the decarbonization of global energy systems. However, its early development stage makes impact assessment difficult. Moreover, rising popularity in carbon pricing necessitates the development of a methodology for deriving carbon abatement costs that are harmonized with the price of carbon. We develop, using a combined bottom-up analysis and top-down learning curve approach, a levelized cost of carbon abatement (LCCA) model for assessing the true cost of emissions mitigation in CCUS technology under carbon pricing mechanisms. We demonstrate our methodology by adapting three policy scenarios in Canada to explore how the implementation of CO2-to-diesel technologies could economically decarbonize Canada's transportation sector. With continued policy development, Canada can avoid 932 MtCO2eq by 2075 at an LCCA of CA$209/tCO2eq. Technological learning, low emission hydroelectricity generation, and cost-effective electricity prices make Quebec and Manitoba uniquely positioned to support CO2-to-diesel technology. The additional policy supports beyond 2030, including an escalating carbon price, CO2-derived fuel blending requirements, or investment in low-cost renewable electricity, which can accelerate market diffusion of CO2-to-diesel technology in Canada. This methodology is applicable to different jurisdictions and disruptive technologies, providing ample foci for future work to leverage this combined technology learning + LCCA approach. [ABSTRACT FROM AUTHOR]

Comprehensive evaluation of greenhouse gas emission reductions from alternative vehicle powertrains requires the use of a life cycle assessment methodology, which considers manufacturing, utilization and end-of-life phases of the vehicle and fuel production. However, vehicle powertrain technologies and regional electricity and fuel production characteristics are evolving rapidly, making such studies performed using current data obsolete in few years. For example, regional electricity generation mixes across the Canadian provinces are largely different, and they are likely to evolve with the introduction of renewable electricity. Hence, there is a general need for adaptable and flexible life cycle assessment frameworks for the transportation sector for rapid evaluation of GHG reductions using up-to-date data. The objective of this study is to develop an adaptive life cycle assessment framework for light duty vehicles that can incorporate critical new developments in vehicle powertrain technologies and changes in electricity and fuel supply. Conventional, hybrid, plug-in hybrid, battery electric and fuel cell powertrain types are included in the framework as parametrized models. Critical parameters related to vehicle size and battery capacity, fuel consumption, mileage, battery chemistry, vehicle hybridization, and electricity and fuel emission intensity are incorporated. The framework was demonstrated by applying it in the Canadian context with the analysis of scenarios associated with electricity grid emission intensity, mileage, battery capacity and battery chemistry. [ABSTRACT FROM AUTHOR]

The separation of lignin from the black liquor generated during alkaline pulping is reviewed in this article with an emphasis on chemistry. Based on published accounts, the precipitation of lignin from spent pulping liquor by addition of acids can be understood based on dissociation equilibria of weak acid groups, which affects the solubility behavior of lignin-related chemical species. Solubility issues also govern lignin separation technologies based on ultrafiltration membranes; reduction in membrane permeability is often affected by conditions leading to decreased solubility of lignin decomposition products and the presence of colloidal matter. Advances in understanding of such phenomena have potential to enable higher-value uses of black liquor components, including biorefinery options, alternative ways to recover the chemicals used to cook pulp, and debottlenecking of kraft recovery processes. [ABSTRACT FROM AUTHOR]

Bioenergy pathways based on waste-to-energy (WTE) technologies are potential solutions to address two major societal challenges: climate change and a lack of sustainable municipal solid waste (MSW) diversion solutions. This study identifies and addresses the absence of an integrated decision-making framework that includes upstream operations (collection, separation, and delivery) and energy recovery technologies of the MSW supply chain. Modeling tools are developed for each WTE stage and integrated for the first time under a single cost and carbon footprint assessment framework. This framework is validated using two case studies to capture urban and rural characteristics. The first pathway includes gasification and an Internal Combustion Engine, and the second pathway consists of combustion and an Organic Rankine Cycle. The outcomes of this study show that Greenhouse Gas (GHG) emissions of the WTE pathways are slightly higher than fossil-based heating. This difference is explained by two factors. First, upstream logistics (often overlooked) are a major contributor to the net GHG emissions (36% in rural cases), and their emissions would offset the potential credits when replacing the current heating systems with the WTE pathways. Secondly, MSW is not entirely carbon neutral, and when the fossil-based carbon is accounted for, WTE pathways show higher GHG emissions for both rural (12–16%) and urban (17–19%) communities, which confirms that the WTE pathways still require more technology optimization and improvement. However, integrated framework revealed that WTE pathways are economically competent to reduce the current heating cost by up to 36% in rural and 25% in urban communities. • A new bottom-up decision making framework has been developed including all upstream and downstream stages. • Two simulation tools has been used to model upstream and downstream stages of multiple waste to energy pathways. • The new framework has been validated through two Canadian case studies covering specificities of urban and rural communities. • Plastic waste stream is included as a mix in the feedstock providing a practical recycling pathway. • Cost and GHG breakdown are used to identify conversion technology gaps for future R&D targets. [ABSTRACT FROM AUTHOR]