石化企业生产与能量系统集成建模与优化研究

发布时间：2018-06-14 09:20

  本文选题：石化企业 + 炼厂　； 参考：《浙江大学》2016年博士论文

【摘要】：随着整个社会对能源问题的日益关注,如何提高石化企业生产和管理效率,同时降低生产成本和能耗,已成为企业亟待解决的问题。能量系统作为石化企业的能源产耗核心系统,其运行优化不仅可以提高企业的经济效益,同时也能促进生产过程节能降耗。然而,目前学术界和工程界对石化企业生产计划优化的研究主要从物流方面展开,对能量系统的运行优化,尤其是在生产计划中兼顾能量系统优化的研究与应用还较少。本文首先回顾了国内外石化企业以物流为主的生产计划研究现状和能量系统运行优化进展,根据石化企业工艺生产的实际情况,按照空间和生产流程分解,以炼厂和乙烯厂为典型对象,分别构建集成工艺操作条件的生产计划非线性优化模型,能量系统多周期混合整数线性规划(Mixed-integer programming, MILP)运行优化模型。以此为基础,建立集成炼厂生产系统与能量系统的混合整数非线性规划(Mixed-integer nonlinear programming, MINLP)模型,集成能耗和工艺条件的乙烯厂计划优化模型,以及集成上游炼厂与下游乙烯厂的多周期生产计划模型。通过对多系统集成优化进行系统而深入的研究,说明未来石化企业实现多介质多系统多周期集成优化的必要性与可行性。本文的主要内容和创新点如下：1)针对目前炼油企业生产计划与实际生产操作脱离较大的应用现状,根据炼油厂的实际生产情况,采用数学规划方法,在装置物料平衡模型中引入可变产率约束条件,建立集成常减压装置(Crude oil Distillation Unit, CDU))切割温度和催化裂化装置(Fluid Catalytic Cracker, FCC)转化率的非线性规划模型。提出基于物料质量平衡和产品质量指标约束的集成优化框架,优化求解确定具体的装置操作条件,提高炼厂生产计划的可执行度。2)提出石化企业能量系统各类产耗能设备的通用建模方法,构建能源量系统运行优化框架,采用数学规划法思想,引入分段线性(piecewise linear)方法对锅炉、透平等重点产能设备进行线性回归建模。通过混合整数线性规划数学模型来描述蒸汽动力系统的运行状况,从物料传递、能量平衡、环境影响三方面建立石化企业能量系统多周期运行优化模型,为石化企业能量系统的操作优化,以及接下来与物流系统的集成提供建模基础。3)通过分析炼厂生产工艺特点,提出物流与能流系统的耦合建模方法,在考虑能源供需平衡、生产单元能耗核算与环境影响的前提下,建立系统间物料与能源多周期质量平衡约束模型,关联负荷与操作方案的生产装置能产能耗核算模型,以及耦合调和物性和锅炉燃料消耗的物性传递模型。从而构建面向炼厂节能减排的生产计划模型,通过对多场景案例验证,为企业的高效生产与节能减排提供优化决策支持。4)针对集成物流与能流的生产计划模型复杂度高与求解时间长等问题,提出一种基于启发式的模型分解策略,引入传统序列分步优化策略确定模型寻优起始点。通过对生产工艺与耦合模型的非凸性分析,对模型双线性约束进行松弛。将原集成混合整数非线性规划模型分解为一个混合整数线性规划模型和一个非线性模型,并迭代求解,通过多场景案例说明算法的实用性。5)针对目前乙烯生产计划优化中,对能源产耗与工艺条件影响考虑不足的现状,构建集成炉管出口温度(Coil outlet temperature,结焦深度等核心工艺条件的裂解炉半机理非线性产率模型和能源产耗模型。通过分析乙烯生产过程中各单元工艺特点,建立集成过程操作和能耗的乙烯装置多周期混合整数非线性规划模型。以某真实化工厂为例,分析集成模型的优化结果,包括装置物流走向、能源产耗计划、设备运行负荷与组合以及蒸汽供需平衡,验证模型实效性。6)从石化企业上下游生产物料和库存平衡,以及生产与能量系统间的能源产耗平衡角度,分析炼厂与乙烯装置间物料与能源工艺耦合关系,建立石化企业多系统集成的混合整数非线性规划模型。基于炼厂和乙烯装置的产品质量平衡与能源供需平衡特点,采用拉格朗日分解算法将原集成模型分解为一个非线性规划炼厂模型,一个混合整数非线性规划乙烯厂模型和一个混合整数线性规划能量系统模型。通过迭代求解,从整个企业网络层面,同时完成炼厂生产计划优化、乙烯装置调度、中间产品库存管理和能量系统运行优化。通过实际案例确定该集成模型与算法的有效性,突出该集成模型在提高生产利润空间与物料利用率方面的优势。7)本研究提出的多系统集成建模框架,立足于石化生产工艺特点,基于国内某大型石化企业中的炼油厂和化工厂生产流程,建立能源设备和生产工艺通用数学模型,可组合为面向炼厂或乙烯厂的生产计划模型,为企业生产运营集成建模奠定了基础。同时,生产系统与能量系统的集成优化,深化了生产过程中物流与能流关系,提高了企业经济效益和能效。
[Abstract]:With the increasing attention of the whole society to the energy problem, how to improve the production and management efficiency of petrochemical enterprises and reduce the cost of production and energy consumption has become an urgent problem for the enterprises. As the core system of energy production in petrochemical enterprises, the energy system can not only improve the economic efficiency of the enterprise, but also promote the economic efficiency of the enterprise. However, at present, the research on the optimization of production planning for petrochemical enterprises is mainly from the logistics, and the research and application of the optimization of the energy system, especially the optimization of the energy system in the production plan, is still less. This paper first reviews the logistics mainly in the petrochemical enterprises at home and abroad. The research status of production planning and the optimization progress of energy system operation are made. According to the actual situation of process production in petrochemical enterprises, according to the decomposition of space and production process, and taking refineries and ethylene plants as the typical objects, the production planning nonlinear optimization model of integrated process operation conditions is constructed respectively, and the multi cycle mixed integer linear programming of energy system (Mixed -integer programming, MILP) operation optimization model. Based on this, the integrated integer nonlinear programming (Mixed-integer nonlinear programming, MINLP) model of integrated refinery production system and energy system, the integrated energy consumption and technological conditions of the ethylene plant planning optimization model, and the integration of the upstream refinery and the downstream ethylene plant are integrated. In order to illustrate the necessity and feasibility of the future petrochemical enterprises to realize multi-media multi system and multi cycle integrated optimization, the main contents and innovation points of this paper are as follows: 1) in view of the large application of the production plan and the actual production operation of the present refinery enterprises. According to the actual production situation of the refinery, the nonlinear programming model of the cutting temperature and the conversion rate of the catalytic cracking unit (Fluid Catalytic Cracker, FCC) is established by using the mathematical programming method and introducing the variable yield constraint conditions in the device material balance model to establish the nonlinear programming model of the conversion rate of the catalytic cracking unit (Fluid Catalytic Cracker, FCC). The integrated optimization framework of material quality balance and product quality index constraints is used to optimize the solution and determine the specific operating conditions and improve the executable degree of the refinery production plan (.2). The general modeling method of all kinds of energy consumption equipment in the energy system of petrochemical enterprises is put forward, and the optimization framework of the energy system operation is constructed, and the idea of mathematical programming is adopted. The piecewise linear (piecewise linear) method is introduced to model the linear regression model of the key production equipment, such as boiler and turbine. Through the mixed integer linear programming mathematical model, the operation status of the steam power system is described, and the multi cycle operation optimization model of the petrochemical enterprise energy system is built from three aspects of material transfer, energy balance and environmental impact. In order to optimize the operation of energy system in petrochemical enterprises and provide modeling basis for the integration of the logistics system, the coupling modeling method of logistics and energy flow system is proposed by analyzing the process characteristics of refinery production. The material and energy of the system are established on the premise of considering the balance of energy supply and demand, the energy consumption accounting and the environmental impact of the production unit, based on the analysis of the process characteristics of the refinery production process. The multi cycle quality balance constraint model, the production capacity calculation model of the associated load and the operation scheme, and the physical property transfer model coupled with the harmonization and the fuel consumption of the boiler, the production planning model for the energy saving and emission reduction of the refinery is constructed, and the efficient production and energy saving and emission reduction of the enterprises are proposed by the multi scene case verification. For the optimization decision support (.4), a model decomposition strategy based on the heuristic is proposed to determine the starting point of the model optimization based on the heuristic based optimization strategy. The model bilinear model is analyzed by the non convexity analysis of the production process and the coupling model. Constraints are relaxed. The original integrated mixed integer nonlinear programming model is decomposed into a mixed integer linear programming model and a nonlinear model, and iterative solution is used to illustrate the practicability of the algorithm through multiple scenario cases.5). In view of the current ethylene production planning optimization, the shortage of energy consumption and technological conditions is considered. The semi mechanism nonlinear yield model and energy production model of the cracking furnace with integrated furnace tube outlet temperature (Coil outlet temperature, coking depth and other core process conditions) are built. By analyzing the technological characteristics of each unit in the production process of ethylene, a multi period mixed integer nonlinear programming model of the integrated process operation and energy consumption is set up. A real chemical factory is used as an example to analyze the optimization results of integrated model, including the trend of equipment logistics, energy production plan, equipment operation load and combination and steam supply and demand balance, verification model effectiveness.6) from the balance of production materials and inventory in the upstream and downstream of petrochemical enterprises, and the balance of energy production and energy consumption in the production and energy system. A hybrid integer nonlinear programming model for multi system integration of petrochemical enterprises is established. Based on the product quality balance and energy supply balance of the refinery and ethylene plant, the Lagrange decomposition algorithm is used to decompose the original integrated model into a nonlinear programming refinery model. Mixed integer nonlinear programming ethylene plant model and a mixed integer linear programming energy system model. Through iterative solution, the refinery production planning optimization, ethylene plant scheduling, intermediate product inventory management and energy system operation optimization are completed from the whole enterprise network level. The integrated model and algorithm are determined through practical cases. The effectiveness of the integrated model in improving production profit space and material utilization ratio.7) the multi system integrated modeling framework proposed in this study is based on the characteristics of petrochemical production technology. Based on the production flow of a refinery and chemical plant in a large petrochemical enterprise in China, a general mathematical model of energy equipment and production process is established. It can be combined into a production planning model for refinery or ethe plant, which lays the foundation for the integrated modeling of enterprise production and operation. At the same time, the integration and optimization of the production system and the energy system deepens the relationship between the logistics and energy flow in the production process, and improves the economic efficiency and energy efficiency of the enterprise.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TE65;TQ221.211
，

本文编号：2016883