检索结果-内蒙古大学图书馆

9th International Conference on Simulation and Modelling in the Food and Bio-Industry, FOODSIM 2016

作者： Valdramidis, Vasilis P. Dolan, Kirk Telen, Dries Vanimpe, Jan F.M. Department of Food Studies and Environmental Health Faculty of Health Sciences University of Malta MsidaMSD2080 Malta Department of Food Science and Human Nutrition 135 Trout Food Science Building Michigan State University East LansingMI48824 United States KU Leuven Department of Chemical Engineering BioTeC - Chemical and Biochemical Process Technology and Control Gebroeders De Smetstraat 1 GentB-9000 Belgium

ISBN: (纸本)9789077381922

Commercial thermal and non-thermal processes for food are dynamic, where temperature, water activity, and other variables can change with time. An efficient process design requires knowing the parameters of microbial mathematical models describing the underlying dynamic processes. However, most research to obtain these parameters is performed under simulated constant conditions. The objective of this session is to address some of the recent developments to model predictive microbial dynamics of food processes describing examples on how to perform inverse (parameter estimation) problems for a number of different primary-secondary models. Therefore, appropriate experimental designs, such as optimal experimental design, parameter identification under dynamic conditions, and properly statistical indices to discriminate among models are discussed.

关键词： Inverse problems

来源：评论

学校读者我要写书评

暂无评论

Fault Identification in Batch processes Using process Data or Contribution Plots: A Comparative Study ∗

引用

IFAC-PapersOnLine 2015年第8期48卷 1282-1287页

作者： Sam Wuyts Geert Gins Pieter Van den Kerkhof Jan Van Impe KU Leuven department of Chemical Engineering Chemical & Biochemical Process Technology & Control (BioTeC) Willem de Croylaan 46 3001 Leuven

In statistical process monitoring, contribution plots are commonly used by operators and experts to identify the root cause of abnormal events. Because contribution plots suffer from fault smearing - an effect that possibly masks the cause of an upset - this paper investigates whether automated fault identification can be improved by using process data instead of contributions. Hereto, both approaches (i.e., using either the sensor measurements or their contributions as inputs for a classification model) are tested on the benchmark penicillin fermentation process Pensim, implemented in RAYMOND. To optimize the performance of each approach, different manipulations of both the process data and the variable contributions are introduced based on the nature of the occurring faults. It is observed that these manipulations have a large influence on the classification performance. Furthermore, this paper demonstrates that fault smearing negatively affects the classification based on the variable contributions. It is concluded that automated fault identification is improved by using the process data rather than the variable contributions as model inputs for the case study investigated.

关键词： Batch processes Fault identification Statistical process control (SPC) Classification models Contribution plots

来源：评论

学校读者我要写书评

暂无评论

Structural identifiability analysis of the Anaerobic Digestion Model No. 1 using a local algebraic observability approach

引用

IFAC-PapersOnLine 2015年第1期48卷 470-475页

作者： Joost Lauwers Philippe Nimmegeers Filip Logist Jan Van Impe KU Leuven Department of Chemical Engineering Chemical and Biochemical Process Technology and Control (BioTeC) W. de Croylaan 46 B-3001 Leuven Belgium.

Structural identifiability is a prerequisite for a successful parameter estimation of a dynamical model. ‘Structural’ relates to the theoretical possibility of estimating the parameters under the idealized conditions that all measurements are perfect and continuous, and that the model is a perfect representation of the real process. In this research, the Anaerobic Digestion Model No. 1 (ADM1) is analysed. The model is of great importance in anaerobic digestion modelling. Due to its numerous parameters, however, its structural identifiability is an open question. The used method investigates the local algebraic observability, which is a sufficient condition for structural local identifiability. Different measurement scenarios were tested, as well as the influence of the choice of inputs. The obtained results are optimistic, since in most conditions, nearly all of the initial conditions of the states and the kinetic, stoichiometric and composition parameters are found to be structurally locally identifiable if almost any one of the states is measured. Unidentifiability occurs for the parameters pertaining to inerts and the cations and anions. For these parameters, nevertheless, structurally identifiable parameter combinations are found.

关键词： Identifiability Observability Parameter Estimation Dynamic modelling ADM1

来源：评论

学校读者我要写书评

暂无评论

The Voidage in a CFB Riser as Function of Solids Flux and Gas Velocity

引用

Procedia Engineering 2015年 102卷 1112-1122页

作者： Huili Zhang Jan Degrève Jan Baeyens Raf Dewil KU Leuven Department of Chemical Engineering Chemical and Biochemical Process Technology and Control Section De Croylaan 46 Heverlee 3001 Belgium University of Warwick School of Engineering Coventry CV4 7AL United Kingdom KU Leuven Department of Chemical Engineering Process and Environmental Technology Lab J. De Nayerlaan 5 Sint-Katelijne-Waver 2860 Belgium

Circulating Fluidised Beds (CFBs) are widely applied in the process industry, for mostly gas-solid and gas-catalytic reactions. The riser is the key component of the CFB being the process reactor. The important design parameters are the operating gas velocity (U) and the solids concentration flux (G). The CFB operation starts at moderate to high superficial gas velocities. Its voidage exceeds ∼ 0.9 and is a function of the solids circulation flux. Different flow modes have been presented in literature, and result in an operation diagram where G and U delineate specific operations, from dilute riser flow, through core-annulus flow, to dense riser upflow (mostly at any U, G exceeding 80 to 120 kg m -2 s -1 ). Increasing G whilst maintaining the gas velocity will cause an increase in suspension concentration. The riser flow can hence be characterized by its apparent voidage, ɛ. In the core-annulus operation, clusters of particles reflux near the wall, thus influencing the local radial voidage in the cross section of the riser, and also extending over a given distance, δ, from the wall to the core . Through measurements in CFBs of 0.1 and 0.14 m I.D., the research has been able to determine the average axial and radial voidages of the dense phase within the different regimes, whilst also determining the thickness of the annulus (in CAF-mode). Experimental results will be illustrated and compared with previous empirical equations, shown to have a limited accuracy only both for ɛ, and for the thickness of the annulus in CAF operation. Within the operating conditions tested, results demonstrate that the annulus thickness is about 15 to 20% of the riser diameter in CAF, and that the voidage in the riser is a function of U and G, with riser diameter and distance along the riser length as secondary parameters.

关键词： circulating fluidized bed riser voidage annulus thickness

来源：评论

学校读者我要写书评

暂无评论

Extending a novel class of predictive models to describe the effect of pH on microbial growth 8

Extending a novel class of predictive models to describe the...

引用

8th International Conference on Simulation and Modelling in the Food and Bio-Industry 2014, FOODSIM 2014

作者： Akkermans, Simen Noriega, Estefania Logist, Filip Van Impe, Jan CPMF-Flemish Cluster Predictive Microbiology in Foods OPTHC - Centre of Kxcellence Optimization in Engineering BioTeC - Chemical and Biochemical Process Technology and Control Department of Chemical Engineering KU Leuven W. de Croylaan 46 B-3001 Leuven Belgium Belgium

ISBN: (纸本)9789077381847

Despite all EU efforts to tackle food poisoning and spoilage, about 5,400 outbreaks and 1.3 billion tons of food waste are reported annually, with a significant impact on EU economy and public health. Modelling and simulation of microbial dynamics as a function of processing, transportation and storage conditions is a useful tool to guarantee food safety and quality. The goal of this research is to improve an existing methodology in order to build accurate predictive models based on multiple environmental conditions. The effect of multiple environmental conditions on microbial dynamics is often described by combining the separate effects in a multiplicative way (gamma concept). This idea was extended further in this work by including the effects of the lag and stationary growth phases on microbial growth rate as independent gamma factors. A mechanistic description of the stationary phase as a function of pH was included, based on a novel class of models that consider product inhibition. Experimental results on Escherichia coli growth dynamics indicated that also the parameters of the product inhibition equations can be modelled with the gamma approach. This work has extended a modelling methodology, resulting in predictive models that are (i) mechanistically inspired, (ii) easily identifiable with a limited work load and (iii) easily extendable to additional environmental conditions.

关键词： Food safety

来源：评论

学校读者我要写书评

暂无评论

An individual-based model for anaerobic dynamics of Escherichia coli colonies 8

An individual-based model for anaerobic dynamics of Escheric...

引用

8th International Conference on Simulation and Modelling in the Food and Bio-Industry 2014, FOODSIM 2014

作者： Tack, Ignace Logist, Filip Fernández, Estefanía Noriega Van Impe, Jan CPMF - Flemish Cluster Predictive Microbiology in Foods OPTEC - Center of Excellence Optimization in Engineering BioTeC - Chemical and Biochemical Process Technology and Control Department of Chemical Engineering KU Leuven Willem de Croylaan 46 box 2423 B-3001 Leuven Belgium Belgium

ISBN: (纸本)9789077381847

Traditional models in predictive microbiology describe microbial dynamics in homogeneous liquid food systems. However, most food systems have a semi-solid structure, in which microbial cells grow locally as colonies. Due to the high cell density in these colonies, the environment becomes inhomogeneous as a result of nutrient over- consumption and cell product accumulation. Hence, the individual cells exhibit strongly different behavior according to their position in the colony. Consequently, an individual-based modeling approach, considering the cell as the basic modeling unit, is most appropriate to describe colony dynamics in full detail. In this paper, an individual-based model is developed for anaerobic colony behavior of Escherichia coli K-12. From the simulation, characteristic colony dynamics emerge, such as a linear radius increase. These dynamics result from the pH drop and concomitant cellular stress in the colony center due to accumulation of lactic acid.

关键词： Dynamics

来源：评论

学校读者我要写书评

暂无评论

The Impact of process Variability on Statistical process Monitoring

The Impact of Process Variability on Statistical Process Mon...

引用

Conference on control and Fault-Tolerant Systems

作者： Geert Gins Jef Vanlaer Jan Van Impe KU Leuven Department of Chemical Engineering Chemical and Biochemical Process Technology and Control (BioTeC)

ISBN: (纸本)9781479928569

process simulators are widely used to develop and benchmark techniques for Statistical process Monitoring (SPM). Typically, the simulators are deterministic and do not take process variability into account. However, modern processes in (bio)chemical industry focus on bio-based production with the help of microorganisms, and are, therefore, subject to larger inherent process variability. In this work, the influence of process variability on the performance of SPM is demonstrated in two representative case studies by adding different levels of process variability to the well-known PENSIM benchmark simulator. In the first case study, a significant improvement (i.e., decrease) of fault detection times is observed. It is hypothesized that process variability causes a persistent excitation of the process, resulting in better process monitoring. In the second case study, a slightly poorer prediction of the batch-end quality was observed for increasing biological variability. Both case studies clearly illustrate that process variability has a profound influence on the performance of SPM techniques. When employing computer-generated data for development, testing or comparison of techniques, the use of a simulator that includes process variability is highly recommended.

关键词： statistical process monitoring simulator process monitoring Scanning Probe Microscopy development test

来源：评论

学校读者我要写书评

暂无评论

Gasification of plastic waste as waste-to-energy or waste-to-syngas recovery route

引用

Natural Science 2013年第6期5卷 695-704页

作者： Anke Brems Raf Dewil Jan Baeyens Rui Zhang College of Life Science and Technology The Key Laboratory of Bioprocess of Beijing Beijing University of Chemical Technology Beijing China Department of Chemical Engineering Chemical and Biochemical Process Technology and Control Section Katholieke Universiteit Leuven Heverlee Belgium

The disposal of plastic solid waste (PSW) has become a major worldwide environmental problem. New sustainable processes have emerged, i.e. either advanced mechanical recycling of PSW as virgin or second grade plastic feedstock, or thermal treatments to recycle the waste as virgin monomer, as synthetic fuel gas, or as heat source (incineration with energy recovery). These processes avoid land filling, where the non-biodegradable plastics remain a lasting environmental burden. Within the thermal treatments, gasification and pyrolysis gain increased interest. Gasification has been widely studied and applied for biomass and coal, with results reported and published in literature. The application to the treatment of PSW is less documented. Gasification is commonly operated at high temperatures (> 600℃ to 800℃) in an air-lean environment (or oxygen-deficient in some applications): the air factor is generally between 20% and 40% of the amount of air needed for the combustion of the PSW. Gasification produces mostly a gas phase and a solid residue (char and ashes). The use of air introduces N2 in the product gases, thus considerably reducing the calorific value of the syngas, because of the dilution. The paper will review the existing literature data on PSW gasification, both as the result of laboratory and pilot-scale research. processes developed in the past will be illustrated. Recently, the use of a sequential gasification and combustion system (at very high temperatures) has been applied to various plastic-containing wastes, with atmospheric emissions shown to be invariably below the legal limits. Operating results and conditions will be reviewed in the paper, and completed with recent own lab-scale experimental results. These results demonstrate that gasification of PSW can be considered as a first order reaction, with values of the activation energy in the order of 187 to 289 kJ/mol as a function of the PSW nature.

关键词： Plastic Waste Re-Use Gasification Syngas Char Sustainability Reaction Rate

来源：评论

学校读者我要写书评

暂无评论

Wall-to-Bed Heat Transfer at Minimum Gas-Solid Fluidization

引用

Journal of Powder technology 2014年第1期2014卷

作者： Huili Zhang Jan Degrève Jan Baeyens Raf Dewil Department of Chemical Engineering KU Leuven Chemical and Biochemical Process Technology and Control Section de Croylaan 46 3001 Heverlee Belgiumkuleuven.be School of Engineering University of Warwick Coventry UKwarwick.ac.uk Department of Chemical Engineering KU Leuven Process and Environmental Technology Lab J.P. De Nayerlaan 5 2860 Sint-Katelijne-Waver Belgiumkuleuven.be

The heat transfer from a fluidized bed to the cooling jacket of the vessel has been studied for various powders at minimum fluidization conditions, by both convection and conduction approaches. These heat transfer characteristics are important as the point of transition between packed and fluidized bed operations and are needed in designing heat transfer operations where bubble-flow is not permitted. The effective thermal conductivity of the emulsion moreover determines the contact resistance at the heating or cooling surface, as used in packet renewal models to predict the wall-to-bed heat transfer. In expressing the overall heat transfer phenomenon as a convective heat transfer coefficient, it was found that the results could be fitted by Nu mf, j = 0.01Ar 0.42 .

关键词：

来源：评论

学校读者我要写书评

暂无评论

Simulation of the Anaerobic Digestion of Microwave Pre-Treated Waste Activated Sludge with ADM1

引用

IFAC Proceedings Volumes 2012年第2期45卷 677-682页

作者： Joost Lauwers Lise Appels Jan Van Impe Raf Dewil Chemical and Biochemical Process Technology and Control section Department of Chemical Engineering KU Leuven (University of Leuven) Heverlee Belgium (Tel:32-16-322675)

Abstract The disposal of sludge originating from municipal waste water treatment is a major issue and represents up to 50% of the operating costs of wastewater treatment plants (WWTP). (Appels et al., 2008) This sludge, a by-product of the treatment processes, however, has the potential to be converted into an energy rich biogas, i.e. a mixture of ca. 65% CH 4 and 35% CO 2 , which can be utilized for the sustainable production of heat and/or electricity. Various pre-treatment methods have been suggested in literature for improving the solids reduction and biogas production rate by enhancing the digestion's rate limiting step, i.e. organic matter hydrolysis. They all induce the solubilization of complex particulate matter so this is more rapidly and completely consumed during the anaerobic digestion process. Methods that have been shown to have a positive effect on anaerobic digestion include chemical, mechanical, biological and thermal processes. Microwave disintegration is one of the more recently applied pre-treatment methods. The disintegration is caused by the combination of thermal and athermal effects and may hence provide superior results compared to a heat treatment (Eskicioglu et al., 2007). The application of mathematical models for the optimization of the digestion process is widely acknowledged. Due to the complexity of the microbial process, accurate modelling of anaerobic digestion is, however, a daunting task. A major stride countering this problem was achieved by the development of the Anaerobic Digestion Model no 1 (ADM1) by the corresponding IWA task group (Batstone et al. 2002). This model is ever since, considered to be the state of the art in modelling of anaerobic digestion and has been the platform for further refinements and numerous applications (Batstone et al. 2006). The main aim of this work is to investigate the ability of ADM1 to describe anaerobic digestion of microwave pre-treated sludge. Compared to untreated sludge, the composition

关键词： anaerobic digestion microwave pre-treatment ADM1

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：