数学规划法优化氢网络的应用研究

为实现不同目标函数与超结构网络氢系统稳定性、可靠性与柔性的统一,从超结构网络、目标函数、约束条件3个方面对国内外氢网络优化的研究进展进行综合分析,阐述了数学规划法在氢网络优化设计进程中的发展变迁,指出充分把握加氢、提纯、压缩等渉氢单元的物料、能量、相平衡特点及相互关系,建立有效的超结构网络,结合不同的目标函数选取不同的约束条件,将随机变量的约束转化为联合机会约束,可提高合成网络的工程可行性、改善网络的柔性。     

炼厂氢资源优化利用技术进展

综述了国内外氢气资源优化技术的进展情况,指出了现有方法存在的问题,提出了技术的未来发展方向:夹点方法以图形化的表现形式对系统瓶颈进行呈现,计算过程简单、易懂,但其忽略了压力、杂质等因素对氢气网络的影响,数学规划算法通过系统建模进行详细的模拟计算,其假定氢油比和氢分压的微量变化及杂质因素不会对装置操作和产品分布产生影响,在装置用氢条件变化不大时可实现氢气系统的效益最大化,而当装置用氢条件发生较大变化时这种假设无法成立,对加氢装置进行反应动力学建模工作可以克服这种缺陷。     

Mixing potential: A new concept for optimal design of hydrogen and water networks with higher disturbance resistance

During the last decade, the design methods of hydrogen and water networks have been improved greatly. Since the resulting network structure featuring minimum utility consumption is not unique, other properties such as disturbance resistance have drawn more and more attention. In this article, a novel concept, Mixing Potential, is proposed to improve the disturbance resistance ability of the networks in the design stage. This concept originates from measuring the concentration fluctuation of a single sink, and could be calculated by its graphical and algorithmic definition, respectively. In addition, a sufficient condition for minimizing the Mixing Potential of a single sink has been proved. Based on this sufficient condition, a graphical and its corresponding algorithmic method are proposed to design the hydrogen and water networks with minimum utility consumption. Literature examples illustrate that the disturbance resistance ability of the network can be improved by adjusting the satisfying order of sinks. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3762–3772, 2014     

数学模型在二元复配剂最优配比筛选中的应用

采用共毒系数法对复配剂的最优配比进行筛选可能会造成真正最优配比的漏筛,且工作量大,具有局限性。以朱砂叶螨、菜缢管蚜和亚洲玉米螟为试虫,分别对甲氰菊酯、阿维菌素、辛硫磷、啶虫脒、杀虫单、三唑磷、甲·阿、辛·啶和三·杀进行毒力测定并计算共毒系数Y。将甲氰菊酯、辛硫磷和三唑磷在各自复配剂有效成分中的质量分数k进行反正弦转换(X=arcsin(K)1/2),通过SPSS软件拟和K反正弦转换值与共毒系数的数学模型。甲·阿、辛·啶和三·杀的数学模型为Y1=-30179.08 769.24X1-4.8472X12;Y2=-22025.37 616.45X2-4.2513X22;Y3=-227.45 19.03X3-0.2304X32。对上述3个方程进行求导可得:Y1'=769.24-9.6944X1;Y2'=616.45-8.5026X2;Y3'=19.03-0.4608X3。令Y'=0,则有X1=79.34;X2=72.50;X3=41.30。将X1、X2和X3值分别代入各自的方程可以求得甲·阿、辛·啶和三·杀复配剂的最大共毒系数分别为340.09、321.36和165.50,将X1、X2和X3值代入X=arcsin(K)1/2中可以求得各单剂在复配剂有效成分中的质量分数K值,根据K值可以求得:甲氰菊酯和阿维菌素的最优配比为28∶1;辛硫磷和啶虫脒的最优配比为10∶1;三唑磷和杀虫单最优配比为7.7∶10。     

石化园区厂际提纯回用氢气系统优化

石化园区化肥厂、乙烯厂等富氢气体送往炼油厂,能够缓解炼油厂的氢气亏缺,因而石化园区厂际氢气系统优化具有重要的意义.本文构建了石化园区厂际提纯回用氢气系统超结构模型,以年度化总费用为目标函数,建立优化的数学模型,使用商业优化软件GAMS平台建模,用DICOPT作为求解器.对某石化园区的氢气系统进行了优化,结果表明,总的年度化费用比现行的系统降低了33.1%.     

水平同心型料管道输送的数学模型

在假设条件下,参照管道水力学理论,分别引入运动型料表面和静止管道壁面的摩阻系数,建立水平同心型料管道流的简易数学模型。该模型较好地描述了型料管道的流动特性,能快速计算型料管道输送参数,其计算值和实验测试值非常吻合,适用于型料管道输送原理的研究和管道工程系统的设计。     

Linear segmented polyurethanes. II. A mathematical model for the prepolymerization stage

In the first part of this sequel, an experimental investigation on the synthesis of linear segmented polyurethanes was presented, that included estimation of the kinetic constants at 60°C for the prepolymerization and finishing stages. This work presents two comprehensive mathematical models that simulate the mentioned prepolymerizations, in reactions between two poly(tetramethylene oxide) PTMO macrodiols and an excess of methylene diphenyl diisocyanate. The models require to input the molar mass distribution (MMD) of the initial macrodiol. The single-phase (or homogeneous) model calculates a final MMD of approximately 40,000 different molecular species, and somewhat underestimates the observed molar mass dispersities. The double-phases (or heterogeneous) model produces a better fit of the observed MMDs by simulating two independent polymerizations carried out in parallel. The double-phases model contains three adjustable parameters: the reaction imbalances into both phases, and an “effective” rate constant. In part III of this sequel, the presented models will be extended to simulate the finishing stages. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46946.     

简捷法确定提纯回用氢网络目标值

与只考虑直接回用的氢网络相比,具有提纯单元的氢网络能显著减少新鲜氢气的消耗量,但其设计及求解提纯目标值过程均更为复杂。对于单杂质、提纯单元采用固定浓度模型的提纯回用氢网络,结合此类网络的特点,提出了一种简捷法确定网络目标值。首先假设提纯后氢物流量足够大,由此得出初始提纯夹点。当初始夹点估算正确时,由夹点之下的需求物流和源物流的流量与杂质质量衡算即可得出提纯回用氢网络的目标值;当初始夹点估算不正确时,可以第一次计算结果为基础判断得出正确夹点,再增加一步简单计算,也可得到提纯回用目标值。计算实例表明本文方法计算简单且有效。     

Global superstructure optimization for the design of integrated process water networks

We propose a general superstructure and a model for the global optimization for integrated process water networks. The superstructure consists of multiple sources of water, water‐using processes, wastewater treatment, and pre‐treatment operations. Unique features are that all feasible interconnections are considered between them and multiple sources of water can be used. The proposed model is formulated as a nonlinear programing (NLP) and as a mixed integer nonlinear programing (MINLP) problem for the case when 0–1 variables are included for the cost of piping and to establish optimal trade‐offs between cost and network complexity. To effectively solve the NLP and MINLP models to global optimality we propose tight bounds on the variables, which are expressed as general equations. We also incorporate the cut proposed by Karuppiah and Grossmann to significantly improve the strength of the lower bound for the global optimum. The proposed model is tested on several examples. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

风力发电制氢与氢气网络耦合系统的氢气波动平抑特性分析

将可再生能源发电制氢集成于炼厂氢气系统中,不仅可替代部分氢气公用工程以满足炼厂的氢气需求,同时也可为炼厂中旋转设备提供电能,但可再生能源发电制氢的波动性将影响氢气网络的稳定运行。为了探究风力发电制氢与氢气网络集成中两个子系统平抑风能波动的特性,本文构建了集成风力发电制氢的氢气网络数学优化分析模型,研究了氢气网络平抑风力发电制氢波动的经济性和系统结构特性。研究表明,为了适应可再生能源发电制氢的波动,氢气网络需要更加复杂的网络结构,且风力发电制氢输出的电力和氢气经储能电池和氢气储罐的缓冲调节后仍存在较大波动,氢气网络仍需通过调节公用工程和燃气系统来实现氢气网络的稳定运行。     

棋盘模型在换热网络优化中的应用

针对复杂整数非线性的换热器网络综合和优化问题,文中应用换热网络流程模拟的棋盘模型及其相应的算法,建立了换热网络同步最优综合的数学模型,通过改变网络的结构次序的数学规划优化计算,以10SP1问题为例,获得了优于以往文献的最优换热网络结构。结果表明,文中应用棋盘算法建立的换热网络求解模型及其算法,具有简单、直观、灵活、易实现的特点,能够得到综合性能更优的网络结构。     

Novel method for targeting the optimal purification feed flow rate of hydrogen network with purification reuse/recycle

The purification reuse/recycle is one effective resource conservation strategy. In this article, a novel conceptual method is proposed to identify the optimal purification feed flow rate (PFFR) and the corresponding maximum hydrogen utility savings (HUS) of the hydrogen network with purification reuse/recycle. In this method, the sources and sink‐tie‐lines are divided into three regions according to the purified product and purification feed. The quantitative relationship between the HUS and the PFFR is analyzed for the sink‐tie‐lines and sources of each region. With the quantitative relationship line between the HUS and the PFFR of each source plotted, the quantitative relationship diagram can be obtained and can be used to identify the pinch point and the HUS for a given PFFR. Furthermore, the optimal PFFR and the maximum HUS can be identified easily. Three cases are studied to illustrate the applicability of the proposed method. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1964–1980, 2013     

基于超结构法的热集成间接式功交换网络综合

换热网络综合的研究和应用对于提高能源利用率已被证明是有效的,而用于回收更高品质能量的功交换网络综合的研究仍处于起步阶段。针对间接式功交换网络综合中复杂推动力约束对流股匹配的制约问题,构建了一种考虑级间热集成的拓展超结构,基于线性拟合压缩机和涡轮机的操作曲线,提出了功源与功阱间流股匹配的识别方法;针对压力、流量与温度的高度非凸非线性关系,提出了采用热集成优化每一级入口温度的松弛策略,建立了以年度总费用最小为目标的混合整数非线性规划模型,通过GAMS求解得到最优的间接式功交换网络结构。最后通过一个算例分析,验证所提方法的有效性和可行性。     

再生纺涤纶短纤维优化配料模型研究

根据约束线性规划原理及涤纶短纤维生产过程中物理变化的内在联系,建立了中空涤纶短纤维配料的数学模型,该模型充分考虑了再生涤纶短纤维生产的工艺要求,得到了适合生产需要的配料结果。通过实例模拟配料计算,该模型比常规配料计算更科学。     

A mathematical model of heat and mass transfer in Yankee drying of tissue

Final dewatering in the production of dry creped tissue is performed by Yankee drying, which includes hot pressing followed by simultaneous contact and impingement drying. The present study models Yankee drying and compares simulation results to the data obtained from trials on a pilot tissue machine. It advances models published previously by the representations developed for the transport of heat in the pressing stage and for the heat transfer involved in the dehydration of the cylinder coating spray. The model predicts an average specific drying rate within 4% in the range of the experimental data used.     

不同窑型熟料混合粉磨的数学模拟接触点模型

采用混杂材料的数学模拟理论,建立了可以定量计算不同强度的熟料混合磨制水泥的接触点模型,应用该模型方法可以比较不同窑型熟料混合粉磨制备水泥时掺加熟料的活性效应。在给定两种熟料的情况下,依据此模型可以快捷地判断其混合粉磨的可行性。     

A mathematical optimization framework for the design of nanopatterned surfaces

The recent explosion of capabilities to fabricate nanostructured materials to atomic precision has opened many avenues for technological advances but has also posed unique questions regarding the identification of structures that should serve as targets for fabrication. One material class for which identifying such targets is challenging are transition‐metal crystalline surfaces, which enjoy wide application in heterogeneous catalysis. The high combinatorial complexity with which patterns can form on such surfaces calls for a rigorous design approach. In this article, we formalize the identification of the optimal periodic pattern of a metallic surface as an optimization problem, which can be addressed via established algorithms. We conduct extensive computational studies involving an array of crystallographic lattices and structure‐function relationships, validating patterns that were previously known to be promising but also revealing a number of new, nonintuitive designs. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3250–3263, 2016     

A bi‐criterion optimization approach for the design and planning of hydrogen supply chains for vehicle use

In this article, we address the design of hydrogen supply chains for vehicle use with economic and environmental concerns. Given a set of available technologies to produce, store, and deliver hydrogen, the problem consists of determining the optimal design of the production‐distribution network capable of satisfying a predefined hydrogen demand. The design task is formulated as a bi‐criterion mixed‐integer linear programming (MILP) problem, which simultaneously accounts for the minimization of cost and environmental impact. The environmental impact is measured through the contribution to climate change made by the hydrogen network operation. The emissions considered in the analysis are those associated with the entire life cycle of the process, and are quantified according to the principles of Life Cycle Assessment (LCA). To expedite the search of the Pareto solutions of the problem, we introduce a bi‐level algorithm that exploits its specific structure. A case study that addresses the optimal design of the hydrogen infrastructure needed to fulfill the expected hydrogen demand in Great Britain is introduced to illustrate the capabilities of the proposed approach. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

A mathematical model for predicting the soil nitrogen status under varying fertilizer practices in a continuous cropping sequence

A mathematical model has been proposed for predicting the changes in soil nitrogen status due to continuous fertilization in a continuous cropping sequence. The model also enabled the prediction of the steady state of soil nitrogen for a specified fertilizer practice.The model was applied to six years nitrogen availability data of four fertilizer practices in finger millet-maize-cowpea sequence followed in the Long Term Fertilizer Experiments conducted at Tamil Nadu Agricultural University, Coimbatore, India. The agreement between the predicted soil nitrogen status by the model and the actuals was proved by employing reliability index.