Supply chain optimization of continuous process industries with sustainability considerations

Single and Multiobjective Shutdown Optimization of a Multistage Continuous Crystallizer

This study presents the first model-based optimal shutdown procedure of a multistage continuous crystallization process which aims at the maximization of on-spec production and minimization of the shutdown time. The cooling antisolvent crystallization of Aspirin (acetylsalicylic acid) in a three-stage continuous crystallizer was used as a case study. To address the optimal shutdown problem, several single optimization scenarios were considered to assess the impact of the degrees of freedom, discretization schemes, and optimization settings such as the constraints. The proposed optimal shutdown procedures showed that significant amounts of on-spec crystals can be produced both at fixed and variable shutdown times. Most importantly, the optimal shutdown procedures can match the steady-state productivity, based on the shutdown to steady-state productivity ratio (STSPR) which can easily reach 100%. Moreover, the residual shutdown material, considered as waste, can be dramatically reduced by >80% compared to the current standard shutdown procedures. Given the conflicting nature of the maximization of on-spec production and minimization of the shutdown time, multiobjective optimization of the shutdown operation was also addressed to identify the set of Pareto optimal solutions. Finally, a multicriteria decision-aiding method, based on multiattribute utility theory, was proposed to rank the Pareto optimal solutions to support the decision-making and help identify a suitable and feasible single optimal shutdown solution.

Opportunities for Using Analytical Hierarchy Process in Green Building Optimization

The adoption of green building technology has become significant for ensuring sustainable development; it has become the main step to a sustainable future. The designs for green buildings include finding a balance between comfortable home construction and a sustainable environment. Moreover, the application of emerging technology is also used to supplement existing methods in the development of greener buildings to preserve a sustainable built environment. The main problem of this research is how to tackle the environmental parameters balance based on new techniques that are being used for green building optimization. To mitigate the cumulative effect of the constructed climate on human wellbeing and the regular ecosystem, the most popular goals for green buildings should be planned. This can be achieved by efficient use of natural resources such as energy, water, and other resources and minimizing waste. This will contribute to the security of occupant health, enhancement of work performance, emissions control, and improvement of the environment. In the construction of green buildings, several criteria that may contradict, interrelated indistinct and of qualitative and/or quantitative environment are broadened to utilize. This paper provides a detailed state of the art analysis on improving existing practices in green architecture/building using analytical hierarchy process (AHP) techniques to tackle the environmental balancing values based on optimal strategies and designs by green solutions to help make the best possible option from numerous options.

Sustainability, cooperation and mobility of workers within and between European countries: a two-stage goal programming model

Facing multiple and often considered as conflicting stakes, either economical, migratory, or environmental, policy-making may struggle to identify and implement relevant policy action allowing for balanced and joint completion of such challenges. Addressing this important public issue, we develop a multi-criteria two-stage Goal Programming (GP) model to identify optimal policy paths towards the Europe 2020 strategy on economic growth, employment levels and environmental sustainability. The model is calibrated on current contributions of economic sectors in all European countries to each policy objective: contribution to economic output (GDP), emissions of Green House Gas, electric consumption and number of jobs. First, we study the optimal allocation of workers within economic sectors of each European country to maximize the joint achievement of Europe 2020 multi criteria sustainability targets. We then extend the model to allow cooperation between states, namely allowing internal migrations of workers between countries. We highlight how supranational allocation schemes of surplus workers improve the satisfaction of national sustainability objectives. Finally, we consider extra-European migrants regional integration and study the consequences of such opening over EU2020 targets satisfaction and per capita GDP. Simulation results highlight countries performance comparison, and sheds light on significant benefits from such cooperation for the majority of countries. Improved integration of internal and external workforce generally improves the achievement of EU2020 objectives, while keeping per capita GDP at least constant. Moreover, we expose the relevance of cooperative work-flows allocation strategies across Europe and emphasize the importance of workers mobility in order to ensure more sustainable common development.

Sustainable Liquefied Natural Gas Supply Chain Management: A Review of Quantitative Models

Natural gas is an essential fuel in the transitions towards a sustainable energy future as it is considered a cleaner source of fuel when compared to other hydrocarbon sources. To enable natural gas delivery from the producer to consumers, natural gas is liquified to enhance transportation efficiency and reliability. The main contribution of this paper is to develop sustainable LNG supply chain through a review of different sustainable supply chain management tools and assessing their applicability in managing LNG supply chains. Energy security has evolved to include the protection of the entire energy supply chain and infrastructure rather than a consideration for the availability of resources alone. There is a particular focus on coupling sustainability and resilience/risk as part of the need to develop integrated approaches to manage energy supply chains to deliver cargo at minimal cost and environmental impact, and to ensure that supply chains can overcome vulnerabilities withstanding potential disruptions to the supply chain. Outcomes of this review demonstrate the possibility to develop multi criteria models, which consider sustainability dimensions within the LNG supply chains and to integrate parameters that form part of the annual delivery plan ensuring day to day LNG supply chain planning consider multiple objectives.

Components of sustainability considerations in management of petrochemical industries

Sustainability comprises three pillars of social, environmental, and economic aspects. Petrochemical industry has a great inter-related complex impact on social and economic development of societies and adverse impact on almost all environmental aspects and resource depletion in many countries, which make sustainability a crucial issue for petrochemical industries. This study was conducted to propose components of sustainability considerations in management of petrochemical industries.A combination of exploratory study-to prepare a preliminary list of components of sustainable business in petrochemical industries based on review of literature and Delphi-to obtain experts' view on this preliminary list and provide a detailed list of components and sub-components that should be addressed to bring sustainability to petrochemical industries, were used.Two sets of components were provided. First general components, which include stakeholders (staffs, society, and environment) with four sub-components, financial resources with 11 sub-components, improvement of design and processes with nine sub-components, policy and strategy of cleaner production with seven sub-components and leadership with seven sub-components. The second operational components included raw material supply and preparation with five, synthesis with ten, product separation and refinement with nine, product handling and storage with five, emission abatement with eight, and improvement of technology and equipment with 16 sub-components.

Techno-ecological synergy as a path toward sustainability of a North American residential system

For any human-designed system to be sustainable, ecosystem services that support it must be readily available. This work explicitly accounts for this dependence by designing synergies between technological and ecological systems. The resulting techno-ecological network mimics nature at the systems level, can stay within ecological constraints, and can identify novel designs that are economically and environmentally attractive that may not be found by the traditional design focus on technological options. This approach is showcased by designing synergies for a typical American suburban home at local and life cycle scales. The objectives considered are carbon emissions, water withdrawal, and cost savings. Systems included in the design optimization include typical ecosystems in suburban yards: lawn, trees, water reservoirs, and a vegetable garden; technological systems: heating, air conditioning, faucets, solar panels, etc.; and behavioral variables: heating and cooling set points. The ecological and behavioral design variables are found to have a significant effect on the three objectives, in some cases rivaling and exceeding the effect of traditional technological options. These results indicate the importance and benefits of explicitly including ecosystems in the design of sustainable systems, something that is rarely done in existing methods.

Towards sustainable food production: a scenario study of the European pork sector

European pork supply chains, like other agri-food supply chains, currently face numerous challenges such as globalization, emerging markets, changing consumer requirements, and new governmental regulations related to issues such as environmental pollution and food safety. These challenges require continuous innovation of supply chain network structures, reconsideration of business processes, relocation of logistics infrastructures and renewed allocation of chain activities to these infrastructures in order to achieve sustainable performances. This paper presents a scenario analysis of the spatial allocation of pork supply chain activities in Europe. Supply chain production and distribution activities are optimized in various scenarios based on economic and sustainability performance indicators. A mixed integer linear programming (MILP) model, which includes piglet production, fattening, slaughtering of pigs, processing of pork and pork consumption, is used to analyse the scenarios. The results reveal major opportunities for reductions in cost as well as in CO2 equivalent emissions if a European sector perspective is taken and some chain activities are relocated to other countries. However, as minimizing costs will not always lead to an optimal reduction in CO2 equivalent emissions, a differentiated strategy is needed for the European pork sector to move towards more sustainable production.

Economic and environmental optimization of a multi-site utility network for an industrial complex

Most chemical companies consume a lot of steam, water and electrical resources in the production process. Given recent record fuel costs, utility networks must be optimized to reduce the overall cost of production. Environmental concerns must also be considered when preparing modifications to satisfy the requirements for industrial utilities, since wastes discharged from the utility networks are restricted by environmental regulations. Construction of Eco-Industrial Parks (EIPs) has drawn attention as a promising approach for retrofitting existing industrial parks to improve energy efficiency. The optimization of the utility network within an industrial complex is one of the most important undertakings to minimize energy consumption and waste loads in the EIP. In this work, a systematic approach to optimize the utility network of an industrial complex is presented. An important issue in the optimization of a utility network is the desire of the companies to achieve high profits while complying with the environmental regulations. Therefore, the proposed optimization was performed with consideration of both economic and environmental factors. The proposed approach consists of unit modeling using thermodynamic principles, mass and energy balances, development of a multi-period Mixed Integer Linear Programming (MILP) model for the integration of utility systems in an industrial complex, and an economic/environmental analysis of the results. This approach is applied to the Yeosu Industrial Complex, considering seasonal utility demands. The results show that both the total utility cost and waste load are reduced by optimizing the utility network of an industrial complex.