Optimal Simultaneous Design and Operational Planning of Vegetable Extraction Processes

A general multiperiod linear optimization model is proposed in this study that targets the simultaneous design and operation planning decisions of a multiproduct batch plant for the production of vegetable extracts. A multiperiod environment is considered because of the market and/or seasonal fluctuations. Thereby, the model considers changes from period to period of demands, costs, prices and raw materials supplies. The objective function maximizes the net present value of the profit considering incomes, investments and resources costs, and both product and raw material inventory costs. In the plant design problem, the sequence of operations is already defined and the pursued goal is to determine both unit sizes and its configuration in the plant. Besides the usual duplication in parallel option, a novel design alternative is included which allows adding units in series to perform a given operation. The optimal design is determined by taking into account available discrete sizes of units which corresponds to the real procurement of equipments. The model is formulated by using the linear generalized disjunctive programming (LGDP). A particular plant that produces oleoresins (solvent extracts of herbs and spices) is used to illustrate the proposed approach. Nevertheless, the developed model is general and can thus be applied to any vegetable extraction process.     

多炼厂计划优化模型的应用设计

通过信息技术等新技术与传统炼化产业的紧密结合推动炼化技术实现新突破,实现智能化生产和信息集成,提高生产和管理效率,降低生产成本。炼化行业计划优化技术发展趋势是实现生产计划各环节的集成,依托模型对生产和经营过程进行模拟,增进计划的科学性。本文结合中国石油总部先进计划系统的设计,介绍了多厂模型的总体设计方案,包括原料供应、生产、物流运输、互供料、库存及产品销售等各环节在模型中的表现方式。     

Solvent extraction engineering and design

Many component parts of solvent extraction plants are standardied. However, factors such as different raw materials, meal and oil product requirements, company marketing practices, local economic conditions, future design considerations, layout requirements, individual company standardization programs, utilities characteristics and structural considerations always vary from plant to plant. Therefore, the design of solvent extraction plants can never be completely standardized. Economic considerations must be given for each individual case for steam economizing facilities, mineral oil recovery systems, integration of a new plant with existing plant facilities, and location and availability of existing facilities. Safety and housekeeping cannot be separated from good design. An unprofitable and unsafe plant is never a bargain.     

硫酸钠复分解法生产硫酸钾的技术

硫酸钾是一种重要的无氯钾肥。在各种原料和诸多制取方法中以氯化钾和硫酸盐复分解法最为广泛应用。就我国的钾资源和已掌握的技术以及遇到的实际问题,重点叙述了硫酸钠和氯化钾复分解法的有关工艺流程、产品质量、装置规模、连续操作、设备材料和腐蚀等问题,并进行了探讨。     

Integrated design of agricultural and industrial processes: A case study of combined sugar and ethanol production

Bioethanol production from molasses has advantages in greenhouse gas emissions because of its energy acquisition from bagasse. However, the improvement of bioethanol productivity is challenging; while each elemental technology option can be greatly improved, the trade‐offs between the production of raw sugar and bioethanol are complex. This issue should be addressed through the optimization of the whole system, including both agricultural and industrial processes. In this study, we constructed a model of combined raw sugar and bioethanol production from sugarcane considering agricultural and industrial technology options. Data were acquired through a detailed investigation of actual sugar mills. Case studies on the redesign of combined raw sugar and bioethanol production demonstrated that the simultaneous implementation of both technology options increases production of food, materials, and energy from plant‐derived renewable resources, thus demonstrating the effectiveness of the interdisciplinary approach. © 2016 American Institute of Chemical Engineers AIChE J, 63: 560–581, 2017     

基于P-graph的乙烯裂解原料调度建模与优化

乙烯工业不同的裂解装置间存在着设备、技术上的差别，每一种原料在乙烯工厂不同炉型或工艺的裂解装置的乙烯产品收率、能耗也存在着差别。随着新的乙烯工厂的投产，需要同时运行台数众多的差异化裂解装置，从而为通过优化调度乙烯裂解原料实现提高物效、降低能耗提供了空间。对于此类工厂间原料调度及能耗优化问题提出了一种基于P-graph的建模和优化方法(scheduling generation based on P-graph, SGBP算法)，该算法通过P-graph本身提取过程结构信息的能力，在加速求解的同时，保留了次优解集。之后以两个实际的乙烯厂为研究实例，采用提出的SGBP方法实现了原料调度的建模和优化，该方法与MINLP优化算法的对比分析验证了提出方法的优势：(1)可以同时提供较为丰富的最优解与次优解方案；(2)提出方法的最优结果与MINLP的优化效果相当；(3)优化后的整体能耗下降明显，为生产计划人员选择可采用灵活的原料调配方案提供了多种可选择的运行方案。     

A THRESHOLD-ACCEPTING METAHEURISTIC METHOD FOR SCHEDULING THE OPERATIONS OF DEHYDRATION PLANTS

Dehydration plants are broadly characterized by a multi-product nature chiefly attributed to the utilization of different raw materials to be processed sequentially so that demand constraints are met. Processing of raw materials is implemented through a series of preprocessing operations that together with drying constitute the production procedure of a pre-specified programme. The core of the manufacturing system that a typical dehydration plant involves, is scheduling of operations so that demand is fulfilled within a pre-determined time horizon imposed by production planning. The typical scheduling operation that dehydration plants involve can be formulated as a general job shop scheduling problem. The aim of this study is to describe a new metaheuristic method for solving the job shop scheduling problem of dehydration plants, termed as the Backtracking Adaptive Threshold Accepting (BATA) method. Our effort focuses on developing an innovative method, which produces reliable and high quality solutions, requiring reasonable computing effort. The main innovation of this method, towards a typical threshold accepting algorithm, is that during the optimization process the value of the threshold is not only lowered, but also raised or backtracked according to how effective a local search is. BATA is described in detail while a characteristic job shop scheduling case study for dehydration plant operations is presented.     

Mathematical modeling for simultaneous design of plants and supply chain in the batch process industry

Most supply chain design models have focused on the integration problem, where links among nodes must be settled in order to allow an efficient operation of the whole system. At this level, all the problem elements are modeled like black boxes, and the optimal solution determines the nodes allocation and their capacity, and links among nodes. In this work, a new approach is proposed where decisions about plant design are simultaneously made with operational and planning decisions on the supply chain. Thus, tradeoffs between the plant structure and the network design are assessed. The model considers unit duplications and the allocation of storage tanks for plant design. Using different sets of discrete sizes for batch units and tanks, a mixed integer linear programming model (MILP) is attained. The proposed formulation is compared with other non-integrated approaches in order to illustrate the advantages of the presented simultaneous approach.     

A THRESHOLD-ACCEPTING METAHEURISTIC METHOD FOR SCHEDULING THE OPERATIONS OF DEHYDRATION PLANTS

ABSTRACT

Dehydration plants are broadly characterized by a multi-product nature chiefly attributed to the utilization of different raw materials to be processed sequentially so that demand constraints are met. Processing of raw materials is implemented through a series of preprocessing operations that together with drying constitute the production procedure of a pre-specified programme. The core of the manufacturing system that a typical dehydration plant involves, is scheduling of operations so that demand is fulfilled within a pre-determined time horizon imposed by production planning. The typical scheduling operation that dehydration plants involve can be formulated as a general job shop scheduling problem. The aim of this study is to describe a new metaheuristic method for solving the job shop scheduling problem of dehydration plants, termed as the Backtracking Adaptive Threshold Accepting (BATA) method. Our effort focuses on developing an innovative method, which produces reliable and high quality solutions, requiring reasonable computing effort. The main innovation of this method, towards a typical threshold accepting algorithm, is that during the optimization process the value of the threshold is not only lowered, but also raised or backtracked according to how effective a local search is. BATA is described in detail while a characteristic job shop scheduling case study for dehydration plant operations is presented.     

Optimal Production Planning for Chemical Processes under Uncertain Market Conditions

Due to lack of a systematic reliability analysis, intuitive decisions can often be made in production planning under uncertainty. These decisions will lead to either conservative or aggressive production. In this work, we propose a novel analysis and optimization framework to address this problem, with which the relationship between the profitability and reliability of a planned operation can be quantified. By using probabilistic programming, the solution of the problem provides comprehensive information on the economical achievement as a function of the desired confidence level of satisfying process constraints. The feasible region will shrink and the profit will decrease when increasing the confidence level. For complex plant operations under multiple uncertainties, the sources of risk that have the most significant impacts on the profitability can be identified. Through this approach, an optimal as well as reliable decision for operations can be made, from which a suitable compensation between the profit and the probability of constraints violation can be received. The approach is applied to three problems of production planning under uncertainty and various issues in planning these operations are discussed.     

Energiewirtschaftliche Rationalisierung bei der Projektierung von Chemieanlagen

Reduction of energy costs in planning of chemical plant . Energy consumption in the chemical industry is especially high, and on inclusion of energy sources used as raw materials the energy consumption figures are even doubled. The most important energy consumption data are presented. The economic incentives for the reduction of energy costs have increased with energy price hikes, and project engineering of new chemical plants offers an extensive field for energy saving measures. An account of the basic methods of economic optimisation of chemical plant equipment, with particular regard to the reduction of energy consumption, is followed by a systematic review of the various sectors of chemical plant design in which energy saving measures can be applied.     

Perspektiven des Ölpflanzenanbaus aus der Sicht der deutschen Agrarwirtschaft – Voraussetzungen und Forderungen

Prospects in Oil Plant Cropping from the Viewpoint of German Agricultural Economy - Prerequisites and Acquirements The cultivation of oil crops has a longstanding tradition and has so far been concentrated on the production of vegetable oils for human nutrition. Winter rape plays the dominant role in oil plant cropping here. In addition to its applications in the food sector, rapeseed oil as a renewable raw material also has other potential uses. The utilization of rapeseed oil as a raw material in the chemical industry results in high demands being made of rape breeding and its implementation. The pressure caused by the dramatic surplus production in the EC has resulted in the development of greater efforts to utilize the plants in the industrial sector. As a lubricant, rapeseed oil can already hold its own on a commercial basis. The situation in the fuel sector is different. The production of rape methyl ester, the diesel substitute, is still more expensive than diesel fuel itself. For the use of rapeseed oil as a basic material for tenside production, for solvents and additives in the paint industry and as a basic material for the production of plastics additives, the content of a fatty acid must be raised to above 85%. This would represent a great step in the direction of providing tailor-made, industrially-oriented vegetable oils. Breeding efforts must be intensified in this respect, but no short-term results are to be expected here. The prospects for vegetable raw materials on the basis of a price comparison with fossil raw materials are positive, however, if for instance a regulation specifying the admixture of rape fuel oil and rape diesel, a regulation specifying the use of hydraulic oil and rape lubricants were to be introduced and the environment-policy advantages of this were to be evaluated. As environment awareness increases, the discussion concerning the burdens placed on the atmosphere becomes more intense. The main subject in this connection is the CO₂ regime in the air. The endeavours to return to closed circuits in energy policy are very much in line with the use of renewable raw materials. Since the problems of oil plant cultivation are of such great economic and social-policy importance, they necessitate vigorous political action at national and EC level.     

我国对二甲苯行业分析及发展建议

论述了目前对二甲苯（PX）的工艺技术和我国PX的供需和市场价格情况,分析了供需存在的问题和价格变化的主要因素,同时对市场的发展趋势进行了预测,分析了PX的危害性和环保相关问题。此外,分别从原料、技术、供需、产业布局和目前地区经济发展目标与民众意愿的矛盾等角度对我国PX产业进行了分析,并针对性地对PX的产业发展提出了一些具体的建议：原料多样化,投资多元化,推进产业平衡发展;进一步积极开拓新技术;统筹规划,合理布局,建立一体化基地或产业园区;走出国门,建立全球产业链;疏导民意、科学决策。     

实时优化技术在乙烯装置在线优化中的应用

乙烯产业是重要的石化基础产业,对国民经济、石油化工产业及工业社会起着举足轻重的作用,近年来 在我国经济增长过程中保持着蓬勃发展的态势,但是,由于我国乙烯生产总体技术水平的相对滞后以及乙烯工 业所供原料复杂等因素,导致我国目前乙烯装置与世界乙烯生产先进水平存在一定差距,为了减小这一差距, 达到世界先进水平,离不开工业过程自动化和运用实时优化技术。为此,本文介绍了实时优化技术的国内外发 展现状和该技术在乙烯装置的应用情况,并通过实时优化系统的实施,建立了乙烯装置的全流程严格机理模型, 可以实时跟踪乙烯装置的生产情况,持续不断对装置进行在线优化,使装置的操作达到最佳的经济效益操作点, 此外,在优化中以装置的原料、产品和公用工程等价格为导向,对全装置生产过程自动操作执行,减少了优化 计算和结果执行中的人为干预。分析表明实时优化技术有效实现了乙烯装置增产、节能和降耗的目标,可为乙 烯生产企业创造新增经济效益。     

Produktionslogistik in der chemischen Industrie

Logistics in the manufacture of chemical products. This survery covers the fields of location analysis, organization of operational material flow, and materials management, all of which are interlocked with each other. Logistics problems with location analysis lie in the area of infrastructure, procurement, and distribution. The organization of the operational material flow has to be based on a closed concept, taking simultanously into consideration interests of production techniques and of logistics. Special attention has to be paid to the reciprocal effect of plant and storage capacity. With complex production structures simulation models should be used, including a statistical model of the market demands, systematic variation of material flows, and grouping of technical equipment. Target is a minimization of total cost. For market oriented operation of complex productions, integrated materials management systems have to be employed. The systems supply a transparent material flow starting from the market demands via the control of production up to the procurement of raw materials.     

Retrofit design of heat exchanger network of a fluid catalytic cracking plant and control based on MPC

Nowadays, the optimal control of a heat-integrated plant becomes one of the most important research areas in the chemical industry. The heat transfer between the process and recycle flows may generate instability. Accordingly, the advanced control techniques have the challenging task of assuring the safety of the process operation and providing tight control for the heat integrated plants. Investigation of an entire fluid catalytic cracking (FCC) plant taking into account its complex dynamic behaviour for heat integration design and operation has not been studied yet. The reactor–regenerator, the fractionation column and the heat exchanger network are included in the present study. Using the data from an industrial plant, a complex FCC process simulator was built. The structure of the optimal heat exchange network (HEN) was designed and implemented in the simulator. Comparison between PID and MPC control strategy was done and the incentives of the proposed MPC are revealed.     

Spatially explicit multi-objective optimisation for design and planning of hybrid first and second generation biorefineries

Climate change mitigation has become a binding driver in biofuels production. First generation bioethanol, initially indicated as the most competitive option, is now incurring in ever increasing discredits forcing the transition towards more sustainable productions (i.e. second and third generation technologies). This paper addresses the strategic design and planning of corn grain- and stover-based bioethanol supply chains through first and second generation technologies. A Mixed Integer Linear Programming framework is proposed to optimise the environmental and financial performances simultaneously. Multi-period, multi-echelon and spatially explicit features are embodied within the formulation to steer decisions and investments through a global approach. A demonstrative case study is proposed involving the future Italian biomass-based ethanol production. Results show the effectiveness of the optimisation tool at providing decision makers with a quantitative analysis assessing the economic and environmental performance of different design configuration and their effect in terms of technologies, plant sizes and location, and raw materials.     

Flow-Sheeting-Programme für die Prozeßsimulation

Flowsheeting systems for process simulation. Simulation of process plants with flowsheeting systems has been state of the art in chemical plant design and in the chemical industry for many years. Modern computers now permit steady state simulation of complex chemical plants with sufficient accuracy. This paper outlines the different approaches to steady state process simulation, names the advantages and disadvantages, and gives an outlook on further developments. Process optimization, process integration, and process synthesis will be discussed. The integration of different programs, e.g. the connection between flowsheeting systems and computer-aided design (CAD) will be described. An advance in user friendliness will be reached by latest developments in the field of personal computers and workstations and by database management systems.     

贵州宏福实业开发有限总公司磷肥厂磷肥装置与美国Farmland和IMC的评比

将贵州宏福实业开发有限总公司DAP装置与其原设计模式装置——美国Farmland和IMC磷肥装置的总图布置、工艺流程进行对比;并评比各装置操作的合理性。从合理性评比中可看出设计中的优点与不足,供同类行业在设计、生产技改中借鉴。