دانلود رایگان مقاله لاتین پلیمریزاسیون از سایت الزویر
عنوان فارسی مقاله:
برآورد پارامتر با تجزیه و تحلیل توانایی برآورد اعمال شده برای فرآیند پلیمریزاسیون مقیاس صنعتی
عنوان انگلیسی مقاله:
Parameter estimation with estimability analysis applied to an industrial scale polymerization process
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
The mathematical modeling must describe the process in an accurate and generalized manner, providing a trustworthy mechanism for evaluating the studied phenomena. In order to obtain accurate and reliable phenomenological model,the parameter estimation is a critical step, since incorrect parameters might lead to a significant degradation of the model predictive capacity (Benyahia et al., 2013). When approaching polymerization processes modeling, the parameters estimation becomes even more important and challenging due to the complex and large-scale models. These models present a great number of unknown parameters, which describes, a.o., quality properties such as melt index and density, kinetic constants, physical and transport properties, such as heat capacity and viscosity. In order to estimate these parameters, experimental data must be available, either from laboratory or industrial scale. Although modeling and parameter estimation for polymerization reactors have been vastly studied in the last decades (Charpentier et al., 1997; Kou et al., 2005; Kiparissides 2006; Embiruc¸ u et al., 2008; Mogilicharla et al., 2014; Pater et al., 2002), just a few number of works performs an estimability analysis in order to evaluate which parameters should indeed be estimatedand very few works focus on industrial scale models, considering the challenges faced in this case (Mjalli and Ibrehem, 2011). Estimability tries to indicate the parameters with higher impact on the model output, classifying them in order of influence. According to Quaiser and Mönnigmann (2009), the methods of estimability analysis try to verify the viability of estimating the parameters of a model based on the input and output data of the system. This preliminary step is particularly critical in the parameter estimation of complex models, as the ones for polymerization processes, as they normally present dozens of parameters which might be correlated. In these cases, it may be impossible to estimate the whole set of parameters due to their correlations and the limited amount of data available. The preliminary analysis of estimability,thus, allows simplifying the optimization problem due to the lower number of parameters to estimate. The objective of this work is to estimate the parameters of a phenomenologicalmodel representing anindustrial scale polymerization reactor (Pontes et al., 2010), carrying outfirst an estimability analysis. The high pressure and temperature conditions hinder a precise representation of the system by pilot plant or laboratory experiments, practices which are very costly. The alternative then is to use measurements directly obtained at the industrial practice. This approach usually offers some challenges since experiments cannot be designed for this purpose and lower amount of data is available because not every variable, like the polymer properties, can be measured online. A preliminary analysis becomes then even more important to reduce the number of parameters to beestimated since some of them might be correlated or might not influence process outputs. Table 1 presents a group of published works in the last decade about parameters estimation applied to polymerization processes. It indicates the studies which perform a preliminary analysis of the parameters as well as the scale where the data were collected. The works which perform the estimability analysis use laboratorial or pilot plant data. Yao et al. (2003), when estimating the parameters of the ethylene gas phase copolymerization with Ziegler-Natta catalyst, developed the orthogonalization method. Benyahia et al. (2013) use the orthogonalization method (Yao et al., 2003) when approaching the copolymerization of styrene with butyl acrylate at lab scale. Due to thehighnumber ofparameters to estimate (49),the authors reports difficulties predicting some polymer properties: mass fraction, average weight and numerical molecular weights and average particles’ diameter. The orthogonalization reduced the number of parameters to be estimated to 21, allowing a successful estimation of the parameters. Kou et al. (2005) present a wellconstructed study about the preliminary analysis of parameters when approaching the phenomenological model of the copolymerization of ethylene with 1-butene in a gas phase pilot reactor with metalocene catalysts. The model validation focuses on polymer properties, such as the incorporated molar fraction of comonomer, the average weight and numerical molecular weights, all of which measured experimentally. The authors use the estimability based on orthogonalization to reduce the number of parameters to be estimated from 22 to 17, thus allowing the satisfactory validation of the model.
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کلمات کلیدی:
Parameter estimation with estimability analysis applied to an industrial ... https://www.infona.pl/.../bwmeta1.element.elsevier-68a0cd6e-26f5-3c6e-98fd-a635266... by IBR Nogueira - 2017 - Cited by 1 - Related articles This paper aims to estimate the parameters of a complex model representing an industrial scale polymerization process. The estimability analysis of the ... Parameter estimation with estimability analysis applied to an industrial ... https://www.infona.pl/resource/bwmeta1.element.elsevier-68a0cd6e.../contributors Parameter estimation with estimability analysis applied to an industrial scale polymerization process. Idelfonso B.R. Nogueira, Karen V. Pontes. Mathematical Model and Parameter Estimation for ... - ACS Publications cdn-pubs.acs.org/doi/abs/10.1021/ie048957o?src=recsys Feb 24, 2005 - Thermal Swing Adsorption Process for Carbon Dioxide Capture and ... with estimability analysis applied to an industrial scale polymerization ... Mathematical Model and Parameter Estimation for ... - ACS Publications pubs.acs.org/doi/full/10.1021/ie048957o?src=recsys Feb 24, 2005 - A dynamic model for gas-phase ethylene homopolymerization using a supported ... from 11 experimental runs in a semibatch laboratory-scale reactor. Estimability analysis techniques were applied to aid in the parameter estimation. .... These high scavenger levels would not be encountered in industrial ... dblp: Karen V. Pontes dblp.uni-trier.de › Persons Dec 2, 2016 - Parameter estimation with estimability analysis applied to an industrial scale polymerization process. Computers & Chemical Engineering 96: ... Pontes, K.V. - 首页 en.ustc.findplus.cn/?h=search_list&query=AR...V.%22 Translate this page Parameter estimation with estimability analysis applied to an industrial scale polymerization process. Academic Journal. 作者: Nogueira, I.B.R. ; Pontes, K.V.. Optimal Flowsheet Configuration of a Polymerization Process with ... onlinelibrary.wiley.com/doi/10.1002/aic.15040/pdf by C Zhang - 2016 - Cited by 1 - Related articles Sep 29, 2015 - to achieve a variety of objectives used for optimizing the per- formance of a reactor network. ... synthesis in polymerization processes remains a complicated and time-consuming task. .... forward to implement at industrial scale. ...... distribution: estimability analysis and multistep methodology. AIChE. J. 2014 ...
