Simulation-based fault propagation analysis—Application on hydrogen production plant

Recently production of hydrogen from water through the Cu–Cl thermochemical cycle is developed as a new technology. The main advantages of this technology over existing ones are higher efficiency, lower costs, lower environmental impact and reduced greenhouse gas emissions. Considering these advantages, the usage of this technology in new industries such as nuclear and oil is increasingly developed. Due to hazards involved in hydrogen production, design and implementation of hydrogen plants require provisions for safety, reliability and risk assessment. However, very little research is done from safety point of view. This paper introduces fault semantic network (FSN) as a novel method for fault diagnosis and fault propagation analysis by using evolutionary techniques like genetic programming (GP) and neural networks (NN), to uncover process variables’ interactions. The effectiveness, feasibility and robustness of the proposed method are demonstrated on simulated data obtained from the simulation of hydrogen production process in Aspen HYSYS^®. The proposed method has successfully achieved reasonable detection and prediction of non-linear interaction patterns among process variables.     

A mathematical approach for retrofit and optimization of total site steam distribution networks

This paper presents a generic mathematical model for retrofitting the steam power plants in an industrial site. The industrial sector under review consists of one steel mill, one oil refinery, and several petrochemical plants, where only small-scale steam integration has been implemented before this study. The relevant unit models in a typical steam power plant are established, and the steam plant retrofit problem is formulated as a mixed-integer nonlinear program (MINLP). Feasible retrofit alternatives suggested by experienced field engineers are investigated in sequence to examine the revenue of those possible modifications. The first scenario examines operational optimization of existent plants; the second option allows installation of one new turbine and replacement of several boilers and turbines with lower efficiency; the third scenario considers using a steam ejector to upgrade the disqualified import steam in the oil refinery. The significant merits from these three retrofit alternatives show that the proposed MINLP formulation has been a great help to enhance the inter-plant steam integration in an industrial sector.     

Fuzzy optimization of multi-period carbon capture and storage systems with parametric uncertainties

Carbon capture and storage (CCS) is an important technology option for reducing industrial greenhouse gas emissions. In practice, CO₂ sources are easy to characterize, while the estimation of relevant properties of storage sites, such as capacity and injection rate limit (i.e., injectivity), is subject to considerable uncertainty. Such uncertainties need to be accounted for in planning CCS deployment on a large scale for effective use of available storage sites. In particular, the uncertainty introduces technical risks that may result from overestimating the limits of given storage sites. In this work, a fuzzy mixed integer linear program (FMILP) is developed for multi-period CCS systems, accounting for the technical risk arising from uncertainties in estimates of sink parameters, while still attaining satisfactory CO₂ emissions reduction. In the model, sources are assumed to have precisely known CO₂ flow rates and operating lives, while geological sinks are characterized with imprecise fuzzy capacity and injectivity data. Three case studies are then presented to illustrate the model. Results of these examples illustrate the tradeoff inherent in planning CCS systems under parametric uncertainty.     

基于CLUE-S和灰色线性规划的嘉兴北部土地利用优化配置研究

构建基于CLUE-S与灰色线性规划混合模型的土地利用优化配置方法,在导入区域政策、社会经济、生态目标和土地利用现状等条件下,进行土地利用数量结构与空间布局的统一优化,并以嘉兴北部地区为例进行实证研究,共设置现状趋势情景、规划目标情景和规划可持续情景这3种模拟情景.规划可持续情景侧重社会经济环境效益,故对建设用地快速增长和农用地持续减少起到明显调控作用,可实现生态敏感区环境和粮食安全的双重保护,是理想的土地利用优化方案.CLUE-S模型与灰色线性规划的耦合能够兼顾现状条件和区域发展目标,模拟土地利用的数量和空间变化,是解决土地资源优化配置问题的有效方法.     

The growing role of web‐based geospatial technology in disaster response and support

This paper examines changes in disaster response and relief efforts and recent web‐based geospatial technological developments through an evaluation of the experiences of the Center for Geographic Analysis, Harvard University, of the Sichuan (2008) and Haiti (2010) earthquake responses. This paper outlines how conventional GIS (geographic information systems) disaster responses by governmental agencies and relief response organisations and the means for geospatial data‐sharing have been transformed into a more dynamic, more transparent, and decentralised form with a wide participation. It begins by reviewing briefly at historical changes in the employment of geospatial technologies in major devastating disasters, including the Sichuan and Haiti earthquakes (case studies for our geospatial portal project). It goes on to assess changes in the available dataset type and in geospatial disaster responders, as well as the impact of geospatial technological changes on disaster relief effort. Finally, the paper discusses lessons learned from recent responses and offers some thoughts for future development.     

突发事件下城市群应急医疗床位共享建模

为给突发事件下城市群应急医疗床位共享提供理论依据,针对突发事件下城市群应急医疗床位共享问题,阐述突发事件下城市群应急医疗床位共享的必要性和可行性,并运用Multi-Hub理论,建立应急医疗床位在城市群集中的优化网络模型,并分析其内涵。在此基础上,采用基于层次分析法的线性回归方法,对多出救点、单个资源、多受灾点的应急医疗床位共享进行优化与讨论,并采用排队分配原则进行应急医疗床位具体去向的落实。研究结果表明:基于Multi-Hub理论的应急医疗床位区域集中优化模型与基于层次分析法的线性规划应急医疗床位调配优化模型,对突发事件下城市群应急医疗床位的共享具有优化和指导作用,能够提高突发事件下城市群应急医疗床位共享的效率,排队分配法能够在不超过医院容纳限度的前提下,保障应急救援的有序性和及时性。     

多目标规划在应急物流中的应用综述

为充分提高突发事件的应急救援效率,应急物流系统的建设至关重要。围绕应急物流系统,从应急物资管理、设施建立以及物流路径规划等方面入手开展相关研究工作的梳理和讨论,结果表明:目前相关研究受限于应急物流的应急体制建设不完善、多目标联系不紧密、信息化程度低、应急物资需求的动态性把握不准确等方面,而根据多目标规划方法提出的相应改进建议,能够实现救援线路最优化、救援时间最短化以及应急投入最小化等多个目标。     

区域联防联控挥发性有机物(VOCs)最优减排方案研究

VOCs区域性联防联控治理是当前彻底治理VOCs污染的有效手段,为了实现VOCs区域性联防联控治理,建立了以减排总量最大、减排成本最低、VOCs减排限产产生的经济影响最小为目标的多目标最优减排模型,提出了基于自适应变异率的分解多目标进化算法（Decomposition Multi-objective Evolutionary Algorithm based on Adaptive Mutation Rate,简称MOEA/DAMA）.选取关中某城市群为研究对象,将VOCs的排放数据代入到最优减排模型中,运用MOEA/DAMA算法对其求解.根据最终的优化结果与MOEA/D初始算法和NSGA-Ⅱ优化算法的优化结果进行对比,结果表明MOEA/DAMA相较于NAGA-Ⅱ和MOEA/D的Pareto解的分布性更广、解的收敛性更高.在对Pareto解的分析上融入决策者的根据实际情况的权衡,计算出更合理的VOCs最优减排方案,为长效科学治理VOCs污染提供借鉴.     

城市内涝灾害应急救援指派模型

为实现应急救援队伍的合理派遣以快速营救受困人员,根据城市内涝灾害特点、城市内涝灾害情况和救援资源的分布,综合考虑应急救援队伍的救援效率、救援可靠性、救援时间等因素,构建多目标应急救援指派模型。运用模糊数学思想,将各目标下的属性值矩阵转化为模糊关系矩阵。针对优化模型的特点,采用反点法对模型进行求解。为证明反点算法的可行性,采用标准匈牙利算法对模型进行求解并加以验证。算例结果表明,多目标优化方案可以进行良好的任务分配,可满足应急救援任务的需要。     

线性规划法计算工业区大气承载力的探讨

分析了目前我国常用的模拟法、线性规划法和A-P值法三种大气承载力计算方法各自的缺点和局限性,探讨了线性规划法在工业园区规划环评大气承载力计算中的应用。以福建省某石化工业园区为实例,采用线性规划法计算了大气环境对SO2的承载力并用模拟法进行验证,计算结果10846t/a与模拟法结果13141t/a吻合性较好,表明线性规划法是计算区域大气承载力的科学可行的方法。