本文關(guān)鍵詞： 物性計算 代理模型 流股和單元 自動化實現(xiàn) 空氣分離過程 乙烯淤漿聚合　出處：《浙江大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：熱力學(xué)物性計算是化工過程模擬與優(yōu)化計算的基礎(chǔ),它對于流程的收斂性能和求解結(jié)果有著至關(guān)重要的影響。依據(jù)化工對象建立的機理模型通常都會涉及到流股或是操作單元的物性數(shù)據(jù),這些物性參數(shù)一般包括了相平衡常數(shù)、密度、焓、熵等。在對模型進行模擬計算前,首先要確定精確可靠的物性計算方法。但在實際體系中的物性計算往往比較復(fù)雜,可能存在以下難點：①使用聯(lián)立方程法建模時,某些涉及到條件判斷、序貫迭代等過程的物性計算過程破壞了模型的全聯(lián)立；②使用代理模型模擬時,求解器無法獲得迭代點的梯度信息；③大規(guī)模過程模型中需要建立數(shù)量眾多的物性計算模塊,建模的成本巨大。針對以上問題,本文的主要研究工作和貢獻如下：1、基于Kriging回歸方法和LHS采樣方法,提出了對熱力學(xué)物性模型建立代理模型的方法,研究了物性模型輸入輸出特征并結(jié)合Kriging回歸方法選擇合適的回歸模型和參數(shù),使得針對不同的物性體系都能得到精度較好的代理模型。2、為了使得物性代理模型有較好的收斂性,提出了代理模型的梯度模型,通過改寫回歸模型的解析導(dǎo)數(shù)得到代理模型的梯度信息,并傳遞給建模平臺下的求解器,使得加入了物性代理模型的全聯(lián)立模型依然保持很好的收斂性。3、針對化工對象流股和操作單元眾多的情況,提出了基于流股和單元的物性建模方法,可以根據(jù)對象物性體系中工況和組成情況快速建立物性代理模型,且滿足最大化復(fù)用性和相互獨立性,降低了建模的成本。4、為了提高建立物性模型的效率,開發(fā)了一套自動化程序和外部函數(shù)模型,用戶可以根據(jù)需求完成物性代理模型的參數(shù)回歸工作并自動生成所需的參數(shù)文件,只需將外部函數(shù)語句寫入原模型中并關(guān)聯(lián)參數(shù)文件即可實現(xiàn)物性代理模型的計算。5、針對空氣分離過程和乙烯淤漿聚合過程,使用了物性代理模型構(gòu)建模型中的物性計算部分,克服了原有物性計算方法存在的條件判斷、序貫迭代等問題,保證了模型的全聯(lián)立,通過模擬結(jié)果驗證了物性計算較好的準確性和收斂性。
[Abstract]:The calculation of thermodynamic properties is the foundation of chemical process simulation and optimization calculation. It plays an important role in the convergence performance of the process and the solution results. The mechanism model based on chemical objects usually involves the physical property data of the flow stock or the operation unit, and these physical parameters generally include the phase equilibrium constant. Density, enthalpy, entropy, etc. Before simulating the model, it is necessary to determine the accurate and reliable calculation method of physical properties. However, the calculation of physical properties in practical systems is often complicated, and there may be the following difficulties: 1, when modeling by simultaneous equation method, Some physical properties calculation processes involving conditional judgment, sequential iteration and so on destroy the whole simultaneous modeling of the model when the agent model is used to simulate the model. The solver can't get the gradient information of the iteration point in the large-scale process model, which needs to build a large number of physical properties calculation modules, and the cost of modeling is huge. The main research work and contributions of this paper are as follows: 1. Based on Kriging regression and LHS sampling method, a method of establishing agent model for thermodynamic properties model is proposed. This paper studies the input and output characteristics of physical property model and selects appropriate regression model and parameters combined with Kriging regression method. The agent model .2with good precision can be obtained for different physical property systems, in order to make the physical agent model have better convergence. The gradient model of the agent model is proposed. The gradient information of the agent model is obtained by rewriting the analytic derivative of the regression model, and the gradient information is transferred to the solver under the modeling platform. The whole model with physical agent model is still convergent. 3. In view of the large number of flow stocks and operation units of chemical objects, a physical property modeling method based on flow stocks and units is proposed. The physical agent model can be established quickly according to the working condition and composition of the object physical property system, and it can satisfy the maximization of reusability and mutual independence, and reduce the cost of modeling .4. in order to improve the efficiency of building the physical property model, A set of automatic program and external function model are developed. The user can complete the parameter regression work of the physical agent model according to the requirement and automatically generate the required parameter file. The calculation of physical property agent model can be realized by writing the external function statement into the original model and associating the parameter file. For the air separation process and ethylene slurry polymerization process, the physical properties calculation part of the physical property agent model is constructed by using the physical property agent model. It overcomes the problems of conditional judgment and sequential iteration in the original physical property calculation method, and ensures the whole simultaneous operation of the model. The simulation results verify the accuracy and convergence of the physical property calculation.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ013.1;TQ019

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