On the use of filters to facilitate the post-optimal analysis of the Pareto solutions in multi-objective optimization

Multi-objective optimization (MOO) has emerged recently as a useful technique in the design and planning of engineering systems because it allows identifying alternatives leading to significant environmental savings. MOO models typically contain an infinite number of Pareto solutions, from which decision-makers should choose the best one according to their preferences. An approach is here presented that identifies and retains for further inspection a reduced set of Pareto solutions showing better overall performance. The capabilities of our approach are illustrated through its application to the design of reverse osmosis desalination plants considering simultaneously the unitary production cost and a set of environmental impacts in several damage categories. Our method reduces significantly the number of Pareto points, thereby facilitating the decision-making process in MOO.     

推进规划环评工作存在的问题及建议对策研究

该文基于笔者从事环境影响评估多年的工作经验,对规划环境影响评价发展过程中存在的主要问题进行了思考和总结,并提出了解决相应问题的对策建议,以期能对国内规划环境影响评价工作的有效推进提供一些参考。     

考虑环境影响的产业规划决策

在工业规划决策中,引入环境价值与环境容量的概念对环境影响因素进行量化的评估,纳入经济效益优化,以达到经济、环境效益的综合最优。提出了以绿色效益F、绿色效益率E来量化产业发展的经济和环境效益的总体优劣,建立了以绿色效益F为目标函数的产业规划决策数学模型。以某磷化工产业为背景,进行了案例计算分析。     

高速公路环境影响评价主要技术方案探讨

高速公路建设项目施工和营运将对沿线区域环境产生一定的影响。环境影响评价应对项目沿线进行现场踏勘,重点走访项目沿线林业、环保、城建、水利等部门,收集公路沿线珍稀植物、古树名木、水源地分布、相应的环境功能区划、城市规划等相关资料。在对项目区域环境现状调查的基础上,编制完成环境影响报告书。其目的是为项目决策提供依据,指导项目环境保护设计和施工期、营运期环境管理,使项目建设达到经济效益、社会效益和环境效益的统一。     

Supply chain redesign through optimal asset management and capital budgeting

Manufacturing and inventory facilities along with the materials present in them are the physical assets of a company. Companies strive to maximize their shareholder values by managing these assets through a variety of business decisions. In this work, we present a new mixed-integer linear programming model for asset management and capital budgeting, which can aid the decision-making process for supply chain redesign. The decisions include facility location, relocation, investment, disinvestment, technology upgrade, production–allocation, distribution, supply contracts, capital generation, etc. To the best of our knowledge, this model is the first to address disinvestment, technology upgrade, material supply contracts, and loans and bonds for capital generation, while including strategic asset management and tactical planning, capacity planning, financial/regulatory factors, and production–distribution. We illustrate the impact of ignoring disinvestment and/or relocation decisions as a 14% decrease in profit for an example case study.     

植物纤维纸蜂窝制备的环境影响评价

利用CML环境影响评价方法,研究并比较了植物纤维纸蜂窝和传统芳纶纸蜂窝制备的环境影响。结果表明,针对所涉及的11个环境影响指标,植物纤维纸蜂窝低于芳纶纸蜂窝0.68 %~49.41 %;权重化结果表明,植物纤维纸蜂窝制备环境影响总体低于芳纶纸蜂窝18.77 %;制备芳纶纸蜂窝的环境影响主要来自于芳纶纸和电能的消耗;制备植物纤维纸蜂窝的环境影响主要来自于混杂纸和电能的生产。     

A property‐based approach to the synthesis of material conservation networks with economic and environmental objectives

This article presents a multiobjective optimization model for the recycle and reuse networks based on properties while accounting for the environmental implications of the discharged wastes using life‐cycle assessment. The economic objective function considers fresh sources and treatment costs, whereas the environmental objective function is measured through the eco‐indicator 99. The model considers constraints in the process sinks as well as in the environment based on stream properties such as pH, chemical oxygen demand, toxicity, density, and color, in addition to the composition of the waste streams. A global optimization procedure is developed by indirectly tackling properties through property operators and by segregating the process streams before treatment. Three examples are included, and the results show that it is possible to consider simultaneously the trade‐offs between the total annual costs and the overall environmental impact using the proposed methodology. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Life cycle assessment of oxygen-18 production using cryogenic oxygen distillation

In this study, life cycle assessment of oxygen-18 by using cryogenic distillation of oxygen is performed using SimaPro 8.3 software. Life cycle assessment is performed to understand the environmental profile and hotspots of this process in order to be used in design and development. Simulation of oxygen-18 process is executed by Hysys software, and the required inputs and outputs for inventory of life cycle were acquired. By doing life cycle assessment and considering achieved results after characterization and normalization of inventory data it has been investigated that in the majority of environmental impacts electricity consumption has a huge contribution relative to other parts of the system like liquefied oxygen production from air separation unit, required facilities for air separation and oxygen-18 units, and needed transportation. Also, among 17 impact categories investigated in ReCiPe impact assessment method, fossil depletion, climate change (human health), particulate matter formation, climate change (ecosystem), human toxicity, and metal depletion have the most contribution in entire environmental loads respectively. Furthermore, sensitivity analysis showed that changing life cycle impact assessment method from ReCiPe to IMPACT 2002 + has no significant effect on acquired results and results are confident. In addition, assumption of market for depleted oxygen from heavy isotopes which is withdrawn from top of distillation columns showed some positive effects compared to first case and environmental impacts resulted from liquefied oxygen production (feed) reduced but because of huge contribution of electricity consumption compared to other sections, this positive effect has no remarkable influence on entire environmental loads of product system.     

Design and planning of infrastructures for bioethanol and sugar production under demand uncertainty

In this paper, we address the strategic planning of integrated bioethanol–sugar supply chains (SC) under uncertainty in the demand. The design task is formulated as a multi-scenario mixed-integer linear programming (MILP) problem that decides on the capacity expansions of the production and storage facilities of the network over time along with the associated planning decisions (i.e., production rates, sales, etc.). The MILP model seeks to optimize the expected performance of the SC under several financial risk mitigation options. This consideration gives a rise to a multi-objective formulation, whose solution is given by a set of network designs that respond in different ways to the actual realization of the demand (the uncertain parameter). The capabilities of our approach are demonstrated through a case study based on the Argentinean sugarcane industry. Results include the investment strategy for the optimal SC configuration along with an analysis of the effect of demand uncertainty on the economic performance of several biofuels SC structures.     

Clean technology—an introduction

A Clean Technology is a means of providing a human benefit which, overall, uses less resources and causes less environmental damage than alternative means with which it is economically competitive. Life Cycle Assessment is central to Clean Technology, as the way to identify overall resource usage and environmental damage. Pollution Prevention and Waste Minimisation are important parts of Clean Technology, but more fundamental is the shift from selling products to providing services. Some specific technological challenges for the chemical and biotechnology industries are identified.     

A LCA Based Biofuel Supply Chain Analysis Framework

This paper presents a life cycle assessment （LCA） based biofuel supply chain （SC） analysis framework which enables the study of economic, energy and environmental （3E） performances by using multi-objective opti-mization. The economic objective is measured by the total annual profit, the energy objective is measured by the average fossil energy （FE） inputs per MJ biofuel and the environmental objective is measured by greenhouse gas （GHG） emissions per MJ biofuel. A multi-objective linear fractional programming （MOLFP） model with multi-conversion pathways is formulated based on the framework and is solved by using theε-constraint method. The MOLFP prob-lem is turned into a mixed integer linear programming （MILP） problem by setting up the total annual profit as the optimization objective and the average FE inputs per MJ biofuel and GHG emissions per MJ biofuel as constraints. In the case study, this model is used to design an experimental biofuel supply chain in China. A set of the weekly Pareto optimal solutions is obtained. Each non-inferior solution indicates the optimal locations and the amount of biomass produced, locations and capacities of conversion factories, locations and amount of biofuel being supplied in final markets and the flow of mass through the supply chain network （SCN）. As the model reveals trade-offs among 3E criteria, we think the framework can be a good support tool of decision for the design of biofuel SC.     

Evaluating and improving environmental performance of HC's recovery system: A case study of distillation unit

Waste solvents/valuable products in the effluent stream are one of the major environmental problems in the chemical industry if not properly controlled. Separation processes are vital for the recovery of waste solvent/valuable product from the effluent stream to reduce the pollution along with improvement in economic performance. Among the various separation processes, distillation is most widely used. A number of environmental indicators, each satisfying researchers own need, and methodologies such as life cycle assessment (LCA), minimum environmental impact assessment (MEIM), waste reduction algorithm (WAR) and environmental fate and risk assessment (EFRAT) are available for evaluation of environmental performance of chemical processes. In this article, a systematic procedure, introducing an environmental performance index (EPI) based on potential environmental impact (computed from waste reduction algorithm (WAR)), energy consumption, resource conservation and fugitive emission, for evaluating environmental performance is presented. Analytical hierarchy process (AHP) is used at two levels for the determination of weighting of individual categories. The procedure is applied for the study of environmental performance of distillation column (steam stripping column) from a real chemical plant for the recovery of acetone and HC's from the off gases of the distillation fraction (DF) plant. Alternatives are compared using environmental performance index and best alternative is selected.     

Life‐Cycle Assessment of Ammunition Demilitarization in a Static Kiln

The demilitarization of ammunition that has reached the end of life (or become obsolete) has to be carried out with minimum energy and environmental impacts. The Portuguese Armed Forces have significant amounts of ammunition that need to be eliminated. In order to assess and improve ammunition demilitarization, a life‐cycle approach must be adopted. The main goal of this article is to present a comprehensive life‐cycle assessment (LCA) of the ammunition demilitarization performed by the Portuguese company IDD (Industria de Desmilitarização e Defesa). A life‐cycle model was developed for the entire demilitarization process, which involves ammunition dismantling, discharging, the incineration of energetic material, and the subsequent flue gas treatment. A detailed inventory was based on data collected from the IDD. A life‐cycle impact assessment was carried out, based on three complementary methods used to assess a total of ten impact categories: cumulative energy demand (primary energy); CML 2001 (six environmental impact categories) and USEtox (three toxicological categories). The results show that the main contributor in nine out of the ten impact categories is the incineration and gas treatment process, due to the high energy requirements (electricity and propane). Nevertheless, equipment manufacture also has a significant impact in the Human Toxicity (non‐cancer) category, mainly related to the manufacture of the static kiln. These findings enhance our understanding of demilitarization using a static kiln, showing that the associated impacts are significant and should be reduced.     

Designing biomass supply chains within planetary boundaries

The design of sustainable supply chains, which recently emerged as an active area of research in process systems engineering, is vital to ensure sustainable development. Despite past and ongoing efforts, the available methods often overlook impacts beyond climate change or incorporate them via standard life cycle assessment metrics that are hard to interpret from an absolute sustainability viewpoint. We here address the design of biomass supply chains considering critical ecological limits of the Earth—planetary boundaries—which should never be surpassed by anthropogenic activities. Our method relies on a mixed-integer linear program that incorporates a planetary boundaries-based damage model to quantify absolute sustainability precisely. We apply this approach to the sugarcane-to-ethanol industry in Argentina, identifying the optimal combination of technologies and network layout that minimize the impact on these ecological boundaries. Our framework can find applications in a wide range of supply chain problems related to chemicals and fuels production, energy systems, and agriculture planning.     

彬长矿区规划环境影响评价指标体系的建立

环境影响评价指标体系的建立是矿区规划环评的重要内容,指标体系的建立制约着矿区环境目标的实现以及规划方案的优化调整建议。以彬长矿区为例,参阅大量矿区规划环评报告的基础上,参照《规划环境影响评价导则(试行)》及《环境影响评价技术导则煤炭工业矿区总体规划》,结合矿区规划实施后主要的环境影响及规划所在区域自然环境特点、环境制约因素,提出了矿区规划环境影响评价的指标体系。     

Comparison of Oleo‐ vs Petro‐Sourcing of Fatty Alcohols via Cradle‐to‐Gate Life Cycle Assessment

Alcohol ethoxylates surfactants are produced via ethoxylation of fatty alcohol (FA) with ethylene oxide. The source of FA could be either palm kernel oil (PKO) or petrochemicals. The study aimed to compare the potential environmental impacts for PKO‐derived FA (PKO‐FA) and petrochemicals‐derived FA (petro‐FA). Cradle‐to‐gate life cycle assessment has been performed for this purpose because it enables understanding of the impacts across the life cycle and impact categories. The results show that petro‐FA has overall lower average greenhouse gas (GHG) emissions (～2.97 kg CO₂e) compared to PKO‐FA (～5.27 kg CO₂e). (1) The practices in land use change for palm plantations, (2) end‐of‐life treatment for palm oil mill wastewater effluent and (3) end‐of‐life treatment for empty fruit bunches are the three determining factors for the environmental impacts of PKO‐FA. For petro‐FA, n‐olefin production, ethylene production and thermal energy production are the main factors. We found the judicious decisions on land use change, effluent treatment and solid waste treatment are key to making PKO‐FA environmentally sustainable. The sensitivity results show the broad distribution for PKO‐FA due to varying practices in palm cultivation. PKO‐FA has higher impacts on average for 12 out of 18 impact categories evaluated. For the base case, when accounted for uncertainty and sensitivity analyses results, the study finds that marine eutrophication, agricultural land occupation, natural land occupation, fossil depletion, particulate matter formation, and water depletion are affected by the sourcing decision. The sourcing of FA involves trade‐offs and depends on the specific practices through the PKO life cycle from an environmental impact perspective.     

Spatial temperature profiles in an aluminum reduction cell under different anode current distributions

The development of a thermal model to estimate energy distribution in an aluminum reduction cell and its impact on local conditions based on anode current signals are presented. In the Hall–Héroult process, routine practices carried out during operation give rise to spatial energy imbalances and consequently temperature variation in the cell. This phenomenon has been ignored in thermal models developed to date as they are only concerned with overall process dynamics. Implementing anode current signals as model inputs along with the discretization method allows the change of spatial conditions caused by current distribution to be calculated. Simulation studies have been performed to investigate the cell thermal balance affected by anode shorting. The article shows the potential of using anode current signals as model inputs to compute spatial thermal conditions based on the proposed model structure that are not considered in traditional modeling approaches. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1544–1556, 2013     

Combined use of MILP and multi-linear regression to simplify LCA studies

Life cycle assessment (LCA) has become the prevalent approach for quantifying the environmental impact of products over their entire life cycle. Unfortunately, LCA studies require large amounts of data that are difficult to collect in practice, which makes them expensive and time consuming. This work introduces a method that simplifies standard LCA studies by using proxy metrics that are identified following a systematic approach. Our method, which combines multi-linear regression and mixed-integer linear programming, builds in an automatic manner simplified multi-linear regression models of impact that predict (with high accuracy) the damage in different environmental categories from a reduced number of proxy metrics. Our approach was applied to data retrieved from ecoinvent. Numerical results show that few indicators suffice to describe the environmental performance of a process with high accuracy. Our findings will help develop general guidelines for simplified LCA studies that will focus on quantifying a reduced number of key indicators.     

Comparative analysis of the life cycle impact assessment of available cement inventories in the EU

Life cycle impact assessment (LCIA) is one of basic steps in life cycle assessment methodology (LCA). This paper presents a comparative study of the LCIA of different life cycle inventories (LCI) for EU cements. The analysis unit used is the manufacture of 1 kg of cement, from “cradle to gate”. The impact categories considered are those resulting from the manufacture of cement and include greenhouse effects, acidification, eutrophication and summer and winter smog, amongst others.The results of the study highlighted some inconsistencies in existing inventories. As for the LCIA, the main environmental interventions related to cement manufacture were classified and characterised and their effect on different impact categories analysed. Differences observed in evaluation of the impact of cement type were essentially related to their clinker content.     

Sustainable scheduling of batch processes under economic and environmental criteria with MINLP models and algorithms

We address the bi-criterion optimization of batch scheduling problems with economic and environmental concerns. The economic objective is expressed in terms of productivity, which is the profit rate with respect to the makespan. The environmental objective is evaluated by means of environmental impact per functional unit based on the life cycle assessment methodology. The bi-criterion optimization model is solved with the ε-constraint method. Each instance is formulated as a mixed-integer linear fractional program (MILFP), which is a special class of non-convex mixed-integer nonlinear programs. In order to globally optimize the resulting MILFPs effectively, we employ the tailored reformulation-linearization method and Dinkelbach's algorithm. The optimal solutions lead to a Pareto frontier that reveals the tradeoff between productivity and environmental impact per functional unit. To illustrate the application, we present two case studies on the short-term scheduling of multiproduct and multipurpose batch plants.