基于全联立方程的空分过程模拟与优化

发布时间：2018-04-18 10:29

本文选题：空分过程 + 全联立　；参考：《浙江大学》2015年硕士论文

【摘要】：空分过程是将空气进行分离,得到高纯度氧、氮、氩等工业气体的分离过程,其产品广泛应用于化工、石油、冶金、电子、能源、医疗保健、航空航天等各工业领域,对国民经济有着重要的作用。作为复杂的化工过程,空分具有产品纯度高、设备耦合多、关联性强等特点,给流程的模拟和优化带来了较大困难,选择适合的求解方法显得至关重要。联立方程法具有求解速度快、收敛性能好、模拟优化问题切换方便的优点,在化工过程的模拟优化中有着广阔的发展和应用前景。本文针对空分模型的变量耦合严重、非线性强、方程变量维数高的问题,以联立方程法为基础,分别对空分过程的机理建模、模拟和优化展开研究。本文的主要贡献有：1、选择适合计算空分深冷体系的热力学物性计算方法PR和RKS-BM,并实现了三次状态方程法的全联立求解,将热力学模型融入空分机理模型,替代了常规化工模拟软件内嵌序贯算法的复杂计算过程。2、基于空分塔的机理模型,设计了物性参数估计的优化命题,得到了准确的二元交互参数,并探究了内嵌序贯算法和全联立计算方法在迭代过程中的差异,验证了联立方程法在收敛性能上的优势。3、针对Aspen Plus模拟空分过程时收敛性差的问题,提出将全联立方法用于空分过程的模拟与优化。联立的范围包括物性计算模型和单元机理模型,实现了全流程的联立求解。在变工况下对流程进行模拟,采用了相同的初值设定,使模型实现秒级收敛,并证明了模型的准确性。4、研究了空分过程中操作条件和约束的重要性,设计了以能耗、收入为目标的优化命题,通过研究变负荷优化前后各操作变量的变化趋势,得出了规律性的结论。并基于全联立模型,对收敛域、热耦合变化等进行了深入研究。
[Abstract]:Air separation process is the separation process of high purity oxygen, nitrogen, argon and other industrial gases. Its products are widely used in chemical industry, petroleum, metallurgy, electronics, energy, health care, aerospace and other industrial fields.It plays an important role in the national economy.As a complex chemical process, air separation has the characteristics of high product purity, more equipment coupling, strong correlation and so on, which brings great difficulties to process simulation and optimization, so it is very important to select suitable solution methods.Simultaneous equation method has the advantages of fast solving speed, good convergence performance and convenient switching of simulation optimization problem. It has a broad development and application prospect in chemical process simulation optimization.In order to solve the problem of severe coupling of variables, strong nonlinearity and high dimension of equation variables, the mechanism modeling, simulation and optimization of air separation process are studied based on simultaneous equation method in this paper.The main contribution of this paper is to choose the thermodynamic physical property calculation methods PR and RKS-BM, which are suitable for calculating the cryogenic system of air separation, and realize the full simultaneous solution of the cubic equation of state method, and incorporate the thermodynamic model into the air separation mechanism model.Instead of the complex calculation process of embedded sequential algorithm in conventional chemical simulation software. Based on the mechanism model of air separation tower, the optimization proposition of physical property parameter estimation is designed, and the accurate binary interactive parameters are obtained.The difference between the embedded sequential algorithm and the full simultaneous calculation method in the iterative process is discussed, and the convergence performance of the simultaneous equation method is verified. 3. Aiming at the problem of poor convergence in the simulation of air separation process by Aspen Plus,In this paper, the simultaneous method is applied to the simulation and optimization of air separation process.The range of simultaneous operation includes physical property calculation model and unit mechanism model, which realizes simultaneous solution of the whole process.The process is simulated under variable working conditions, the same initial value is used to make the model converge in second order, and the veracity of the model is proved. Finally, the importance of operating conditions and constraints in air separation process is studied, and the energy consumption is designed.By studying the changing trend of operating variables before and after variable load optimization, the conclusion of regularity is obtained.Based on the model, the convergence domain and thermal coupling are studied.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.11

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