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Abstract This article describes the key challenges and opportunities in modeling and optimization of biomass-to-bioenergy supply chains. It reviews the major energy pathways from terrestrial and aquatic biomass to bioenergy/biofuel products as well as power and heat with an emphasis on “drop-in” liquid hydrocarbon fuels. Key components of the bioenergy supply chains are then presented, along with a comprehensive overview and classification of the existing contributions on biofuel/bioenergy supply chain optimization. This paper identifies fertile avenues for future research that focuses on multi-scale modeling and optimization, which allows the integration across spatial scales from unit operations to biorefinery processes and to biofuel value chains, as well as across temporal scales from operational level to strategic level. Perspectives on future biofuel supply chains that integrate with petroleum refinery supply chains and/or carbon capture and sequestration systems are presented. Issues on modeling of sustainability and the treatment of uncertainties in bioenergy supply chain optimization are also discussed.

The production and use of fossil fuels have caused a drastic increase in greenhouse gas emissions, which is associated directly with the global warming problem. Biofuels and carbon capture through forest plantations are interesting alternatives to address this problem. This paper presents an optimization model for the design of an integrated energy system for producing fuels and biofuels considering the interaction with eco-industries able to capture emissions from biorefineries and refineries and receive a monetary benefit. The proposed mathematical model takes into account the availability of biomass, the production of oil, and a set of existing biorefineries and refineries as well as the possibility to install new eco-industries. The mathematical approach was applied to a nationwide case study for Mexico, considering the creation of new jobs, overall emissions, and net profit as objectives. The results are shown in a Pareto curve, which is useful for making decisions about the interactions between thes...

The widespread COVID-19 pandemic led to a shortage in the supply of N95 respirators in the United States until May 2021. In this study, we address the energy, environmental, and economic benefits of the decontamination-and-reuse of the N95 masks. Two popular decontamination methods, including dry heat and vapor hydrogen peroxide (VHP), are investigated in this study for their effective pathogen inactivation and favorable performance in preserving filtration efficiency and structural integrity of respirators. Two multiple reuse cases, under which the N95 masks are disinfected and used five times with the dry heat method and 20 times using the VHP method, are considered and compared with a single-use case. Compared to the single-use case, the dry heat-based multiple-use case reduces carbon footprint by 50% and cumulative energy demand (CED) by 17%, while the VHP-based case decreases carbon footprint by 67% and CED by 58%. The dry-heat-based and VHP-based multiple reuse cases also present environmental benefits in most of the other impact categories, primarily due to substituting new N95 respirators with decontaminated ones. Decontaminating and reusing respirators costs 77% and 89% less than the case of single-use and disposal. The sensitivity analysis results show that the geographical variation in the power grid and the times of respirator use are the most influential factors for carbon footprint and CED, respectively. The result also reaffirms the energy, environmental, and economic favorability of the decontamination and reuse of N95 respirators.

AbstractThis article addresses the sustainable design and synthesis of open‐loop recycling process of waste high‐density polyethylene (HDPE) under both environmental and economic criteria. We develop by far the most comprehensive superstructure for producing monomers, aromatic mixtures, and fuels from waste HDPE. The superstructure optimization problem is then formulated as a multi‐objective mixed‐integer nonlinear fractional programming (MINFP) problem to simultaneously optimize the unit net present value (NPV) and unit life cycle environmental impacts. A tailored global optimization algorithm integrating the inexact parametric algorithm with the branch‐and‐refine algorithm is applied to efficiently solve the resulting nonconvex MINFP problem. Results show that the optimal unit NPV ranges from $107.2 to $151.3 per ton of HDPE treated. Moreover, the unit life cycle greenhouse gas emissions of the most environmentally friendly HDPE recycling process are 0.40 ton CO2‐eq per ton of HDPE treated, which is 63% of that of the most economically competitive process design.

Metaverse sector growth supports energy conservation, boosts renewable energy penetration, lessens fossil fuel dependency, and reduces anthropogenic emissions, such as greenhouse gases and aerosol precursors, thereby aiding climate change mitigation.

Chemical recycling has the potential to reduce the environmental impacts from waste plastics, mitigate climate change, and contribute to circular economy. This study compares the environmental and ...

To optimize the environmental performance and the conflicting economic interests of the main stakeholders that interact within circular integrated waste management systems (CIWMSs), life cycle analysis and a game-theoretical model-based on the Stackelberg equilibrium-were integrated into a multiobjective optimization framework. The framework was used to determine the operational decisions and the configuration of a CIWMS that simultaneously minimize the total global warming impacts (GWIs) and maximize the profits of (i) the waste managers that valorize the municipal organic waste generated in the Spanish region of Cantabria and (ii) the regional farmers that purchase the resulting organic fertilizers. A bilevel optimization problem was formulated and solved by replacing the lower-level problem with its equivalent Karush-Kuhn-Tucker conditions. The balance between the stakeholders' objectives is reflected in the low prices set for the organic fertilizers (0-2 €·metric ton-1 of compost and 0-1 €·metric ton-1 of digestate). Although the minimal GWIs are constrained by the waste managers' profits, it is possible to improve the values of the objective functions by increasing the waste management tax. The proposed framework proved to be useful to plan for a sustainable circular economy, warranting the profitability of organic fertilizers for both ends of the supply chain. The authors acknowledge the financial support from the Spanish Ministry of Education 567 (EST18/00007 and FPU15/01771)

This paper addresses the optimal design and planning of biomass-to-liquids (BTL) supply chains under economic and environmental criteria. The supply chain consists of multisite distributed–centralized processing networks for biomass conversion and liquid transportation fuel production. The economic objective is measured by the total annualized cost, and the measure of environmental performance is the life cycle greenhouse gas emissions. A multiobjective, multiperiod, mixed-integer linear programming model is proposed that takes into account diverse conversion pathways and technologies, feedstock seasonality, geographical diversity, biomass degradation, infrastructure compatibility, demand distribution, and government incentives. The model simultaneously predicts the optimal network design, facility location, technology selection, capital investment, production planning, inventory control, and logistics management decisions. The problem is formulated as a bicriterion optimization model and solved with the ...

Abstract This paper proposes a multiobjective, mixed-integer nonlinear programming (MINLP) model for the superstructure optimization of hydrocarbon biorefineries via gasification pathway under economic and environmental criteria. The proposed hydrocarbon biorefinery superstructure includes a number of major processing stages, such as drying of the cellulosic biomass feedstocks, air separation unit, gasification, syngas conditioning, Fischer–Tropsch synthesis, hydroprocessing, power generation, and the diesel and gasoline production. The superstructure considers alternatives of technologies and equipment, such as gasification technologies, cooling options, hydrogen production sources, and Fischer–Tropsch synthesis catalysts. The economic objective is measured by the net present value ( NPV ), and the environmental concern is measured using global warming potential ( GWP ) that follows the life cycle assessment procedures, which evaluates the gate-to-gate environmental impacts of hydrocarbon biofuels. The multiobjective MINLP model simultaneously determines the technology selection, operation conditions, flow rate of each stream, energy consumption of each unit, economic performance, environmental impacts, and equipment sizes. The multiobjective MINLP problem is solved with the ɛ -constraint method. The resulting Pareto-optimal curve reveals the trade-off between the economic and environmental performances. The optimal solution reveals that the high-temperature gasification, direct cooling, internal hydrogen production and cobalt catalysis have the best environmental and economic performances. At the breakeven point, where the optimal NPV is 0, the unit production cost of hydrocarbon biorefinery is $4.43 per gasoline-equivalent gallon (GEG) with unit GWP of 20.92 kg CO 2 eqv./GEG. In the case of maximum NPV of $810 MM, the corresponding unit production cost is $3.17/GEG.