Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Energetics of Chemical Process.
Rozprawy doktorskie na temat „Energetics of Chemical Process”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Energetics of Chemical Process”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Orr-Ewing, Andrew John. "Laser studies of reaction dynamics". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302888.
Pełny tekst źródła
2
Saraf, Sanjeev R. "Molecular characterization of energetic materials". Texas A&M University, 2003. http://hdl.handle.net/1969.1/331.
Pełny tekst źródłaStreszczenie:
Assessing hazards due to energetic or reactive chemicals is a challenging and complicated task and has received considerable attention from industry and regulatory bodies. Thermal analysis techniques, such as Differential Scanning Calorimeter (DSC), are commonly employed to evaluate reactivity hazards. A simple classification based on energy of reaction (-H), a thermodynamic parameter, and onset temperature (To), a kinetic parameter, is proposed with the aim of recognizing more hazardous compositions. The utility of other DSC parameters in predicting explosive properties is discussed.
Calorimetric measurements to determine reactivity can be resource consuming, so computational methods to predict reactivity hazards present an attractive option. Molecular modeling techniques were employed to gain information at the molecular scale to predict calorimetric data. Molecular descriptors, calculated at density functional level of theory, were correlated with DSC data for mono nitro compounds applying Quantitative Structure Property Relationships (QSPR) and yielded reasonable predictions. Such correlations can be incorporated into a software program for apriori prediction of potential reactivity hazards. Estimations of potential hazards can greatly help to focus attention on more hazardous substances, such as hydroxylamine (HA), which was involved in two major industrial incidents in the past four years. A detailed discussion of HA investigation is presented.
3
Binnie, S. J. "Ab initio surface energetics : beyond chemical accuracy". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1318067/.
Pełny tekst źródłaStreszczenie:
Density functional theory (DFT) is the work–horse of modern materials modeling techniques, but scattered evidence indicates it often fails for important surface properties. This thesis investigates how DFT estimates of the surface energy (σ) and molecular adsorption energies of ionic systems are affected by the choice of exchange–correlation (xc) functional. Accurate diffusion Monte–Carlo (DMC) and quantum chemistry (QC) calculations are presented for these quantities showing marked improvement over DFT and agreement of much better than chemical accuracy. DFT estimates of σ are presented for the (001) surfaces of LiH, LiF, NaF and MgO. Five xc functionals, LDA, PBE, RPBE, Wu–Cohen and PW91 are used. A clear xc functional bias is demonstrated with σLDA > σWC > σPBE > σPW91 > σRPBE. To improve the picture detailed pseudopotential DMC calculations are presented for LiH and LiF. The lattice parameters and cohesive energies agree with experiment to better than 0.2 % and 30 meV respectively. For LiH novel all–electron DMC calculations are also presented showing significant improvement over pseudopotential DMC. Accurate all–electron Hartree–Fock calculations of σ for LiH(001) and LiF(001) are presented along with calculations of the LiF bulk using specially adapted Gaussian basis–sets. Combined with existing QC correlation estimates the bulk and surface properties of LiH and LiF show excellent agreement to both experiment and DMC and allow a longstanding disagreement between two experimental estimates for σLiF to be resolved. Finally the adsorption energy curve for water on LiH(001) is obtained by both DMC and incremental QC techniques leading to agreement of better than 10 meV. DFT and dispersion corrected DFT estimates are also presented highlighting the large xc functional dependence. Thus we demonstrate that is possible and necessary to obtain agreement between higher levels of theory and produce benchmark values beyond DFT.
4
Sresht, Vishnu. "Molecular-thermodynamic and simulation-assisted modeling of interfacial energetics". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107875.
Pełny tekst źródłaStreszczenie:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 189-203).
The heterogeneous molecular interactions that operate at material interfaces control the efficiency of chemical engineering processes as diverse as adsorption, emulsification, heat exchange, and froth flotation. In particular, the process of colloidal self-assembly harnesses the rich tapestry of interactions that operate at several length scales, including van der Waals and electrostatic interactions, the hydrophobic effect, and entropic considerations, to drive the autonomous aggregation of simple building blocks into intricate architectures. This bottom-up approach has increasingly become the mainstay of the colloids community in its quest to design and fabricate increasingly complex soft-matter assemblies for pharmaceutical, catalytic, optical, or environmental applications. Accurately modeling and manipulating interfacial interactions across many different length scales is vital to optimizing the self-assembly and stability of colloidal suspensions. With the above background in mind, in this thesis, I illustrate the modeling of interfacial phenomena at a range of length scales, with a particular focus on utilizing a combination of computer simulations and molecular-thermodynamic theories to evaluate the free energies associated with the formation and reconfiguration of revolutionary colloidal systems, including dynamically-responsive colloids and two-dimensional nanomaterial suspensions. First, I examine the interplay between interfacial tensions during the one-step fabrication, and stimuli-responsive dynamic reconfiguration, of three-phase and four-phase complex emulsions. This fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone, and fluorocarbon liquids and is applied to both microfluidic and scalable batch production of complex droplets. I demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by judicious variations in interfacial tensions, as controlled via conventional hydrocarbon and fluorinated surfactants, as well as by stimuli-responsive and cleavable surfactants. Subsequently, I examine the molecular origins of the ability of surfactants to modulate the interfacial tensions at fluid-fluid interfaces, including developing a computer simulation-aided molecular- thermodynamic framework to predict the adsorption isotherms of non-ionic surfactants at the air-water interface. The use of computer simulations to evaluate free-energy changes is implemented to model a surfactant molecule possessing tumor-selective cytotoxicity. Utilizing potential of mean force calculations, I shed light on the preference of this anti-cancer drug for certain types of lipid bilayers, including advancing a hypothesis for the mechanism through which this drug induces apoptosis. I then utilize potential of mean force calculations to evaluate the formation of colloidal suspensions of two novel two-dimensional materials: phosphorene and molybdenum disulfide (MoS2). I focus on the correlations between the structural features of commonly-used solvents and: (1) their ability to intercalate between nanomaterial sheets and induce exfoliation, and (2) their effect on the energy barrier hindering the aggregation of the phosphorene and MoS2 sheets. The combination of simulation-based computation of the potential of mean force (PMF) between pairs of nanomaterial sheets, as well as the application of theories of colloid aggregation, offers a detailed picture of the mechanics underlying the liquid-phase exfoliation and the subsequent colloidal stability of phosphorene and MOS2 sheets in the commonly-used solvents considered. The agreement between the predicted and the experimentally-observed solvent efficacies provides a molecular context to rationalize the currently prevailing solubility-parameter-based theories, and for deriving design principles to identify effective nanomaterial exfoliation media.
by Vishnu Sresht.
Ph. D.
5
Powers, Daryl E. "Effects of oxygen on embryonic stem proliferation, energetics, and differentiation into cardiomyocytes". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38963.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2007.Includes bibliographical references (p. 106-114).
Most embryonic stem (ES) cell research has been performed using a gas-phase oxygen partial pressure (pO2gas) of 142 mmHg, whereas embryonic cells in early development are exposed to cellular pO2 (pO2cell) values of about 0-30 mmHg. Murine ES (mES) cells were used as a model system to study the effects of oxygen on ES cell proliferation, phenotype maintenance, cellular energetics, and differentiation into cardiomyocytes. It was found that undifferentiated mES cells are capable of surviving and proliferating at pO2 conditions in the range of 0-285 mmHg, with only moderately decreased growth at the extremes in pO2 over this range. Oxygen levels had no effect on the maintenance of the undifferentiated phenotype during culture with the differentiation-suppressing cytokine leukemia inhibitory factor (LIF) in the culture medium, and low oxygen had, at most, a small differentiating-promoting effect during culture without LIF. Aerobic metabolism was used to generate approximately 60% of the energy required by undifferentiated mES cells at high pO2, but substantially smaller fractions when cells were oxygen starved. This shift from aerobic to anaerobic respiration occurred within 48 hr with minimal cell death.
(cont.) Oxygen was found to substantially affect the differentiation of mES cells into cardiomyocytes. Reduced pO2cell conditions strongly promoted cardiomyocyte development during the first 6 days of differentiation, after which oxygen primarily influenced cell proliferation. Using silicone rubber membrane-based dishes to improve oxygenation and an optimized cardiomyocyte differentiation protocol, it was possible to reproducibly obtain 60 cardiomyocytes per input ES cells and a cell population that was 30% cardiomyocytes following 11 days of differentiation. These results, obtained using a pO2gas of 7 mmHg during the first 6 days of differentiation, represent a 3-fold increase relative to those obtained with a pO2gas of 142 mmHg throughout differentiation. This work has shown that undifferentiated ES cells are able to adapt to their environmental pO2 and are relatively insensitive to its variations, whereas during differentiation oxygen affects cell fate decisions. Oxygen control can be used to improve directed ES cell differentiation into cardiomyocytes and oxygen may play a more important role in early embryonic development than heretofore appreciated.
by Daryl E. Powers.
Ph.D.
6
Fien, Gert-Jan A. F. "Studies on process synthesis and process integration". Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-08032007-102242/.
Pełny tekst źródła
7
Peterson, Charles Campbell. "Accurate Energetics Across the Periodic Table Via Quantum Chemistry". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822822/.
Pełny tekst źródłaStreszczenie:
Greater understanding and accurate predictions of structural, thermochemical, and spectroscopic properties of chemical compounds is critical for the advancements of not only basic science, but also in applications needed for the growth and health of the U.S. economy. This dissertation includes new ab initio composite approaches to predict accurate energetics of lanthanide-containing compounds including relativistic effects, and optimization of parameters for semi-empirical methods for transition metals. Studies of properties and energetics of chemical compounds through various computational methods are also the focus of this research, including the C-O bond cleavage of dimethyl ether by transition metal ions, the study of thermochemical and structural properties of small silicon containing compounds with the Multi-Reference correlation consistent Composite Approach, the development of a composite method for heavy element systems, spectroscopic of compounds containing noble gases and metals (ArxZn and ArxAg+ where x = 1, 2), and the effects due to Basis Set Superposition Error (BSSE) on these van der Waals complexes.
8
Yadav, Santosh. "The Energetics of Water Interactions with Adult and Neonatal Skin". University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1259080683.
Pełny tekst źródła
9
Gao, Ying. "Knowledge management in chemical process industry". Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/842919/.
Pełny tekst źródłaStreszczenie:
Information and knowledge are among the major resources in chemical process enterprise. Effective knowledge sharing and decision coordination are important to collaborative product development and integrated manufacturing. The integration of knowledge management in chemical process industry can provide the enterprise an environment for knowledge sharing and coordinate decision-marking, it can also help the enterprise to realize the best value of its knowledge assets and make businesses more competitive and profitable. In this work, an Ontology-based knowledge management system is proposed for knowledge integration and decision support in chemical process industry. Information technology, artificial intelligence and chemical engineering domain technology are integrated into a unified system to support knowledge integration, cooperate manufacturing, enterprise management and information service in chemical process industry. The system infrastructure includes Ontologies, knowledge repository, information retrieving agent, knowledge discovery tools and user interface. Ontology plays an important role in the knowledge management system for knowledge integration, knowledge sharing and reuse. Ontology classifies the knowledge base, integrates sources of knowledge into the knowledge repository, supervise database and user interface construction, and severs as a backbone of the knowledge management system development. A flexible and systematic approach for ontology development and implementation is established in this work to support ontology creation and application in the knowledge management system. Knowledge retrieving services are developed in the knowledge management system to extract information and knowledge from various data sources. Information retrieving agents retrieve information from the knowledge repository according to the user's requirement, and provide cleaned information through information filtering. Ontology-based information retrieving approach is utilized in this work. Data mining technique is applied to extract the implicit and potentially useful information, and also predict trends by mining the historic data. Knowledge management in chemical process industry consists of a set of practices aimed at monitoring the process operation and providing decision support for the engineers and managers. However, currently available computer-aided systems for chemical process engineering are normally isolated, which make it difficult for data and information exchange and decision support. Multi-agent system is utilized in this work to coordinate these tasks and incorporate the disparate information resources. Process simulation, rule- base decision support, artificial intelligence such as artificial neural network (ANN) are integrated in this system for process analysis, data processing, process monitoring and diagnosis, process performance prediction and operation suggestion. A multi-agent system developed on the basis of JADE (Java Agent Development Framework) is integrated in the knowledge management system, in which software agents are designed to perform the tasks of process monitoring, process performance prediction, manufacturing management and information service. With a common communication language and shared ontologies, agents can communicate and cooperate with each other to exchange and share information, and achieve timely decisions in dealing with various enterprise scenarios. The implementation of knowledge management system will provide well-organized information for technical monitoring in chemical process industry, and enable the knowledge integration and sharing among researchers, engineers and managers. The application of the knowledge management system in chemical process industry can also help the engineers to coordinate in manufacturing execution, and provide decision support based on up-to-date information and knowledge.
10
Wang, Chuangnan. "Ultrasonic technique for chemical process control". Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24442.
Pełny tekst źródłaStreszczenie:
Ultrasound has found application in chemical processing control using both low power, high frequency monitoring techniques and high power, low frequency process enhancement approaches. In many cases, standard ultrasonic systems are retrofitted to a process and while these produce efficiency improvements, the design of bespoke systems may offer more potential. In particular, this Thesis has considered two techniques used in the biomedical field; harmonic imaging and high intensity focused ultrasound (HIFU) and has translated these into ultrasonic transducers for use in an industrial process control system. Traditional ultrasound monitoring techniques are based on operation in the linear domain and are used to monitor chemical processes by measurement of material acoustic velocity, attenuation or based on spectral analysis. Both active and passive methods have been reported for application in this industrial sector. One issue is the presence of multiple reflections in the received ultrasonic signal which can mask the signals of interest from the load medium. This Thesis has considered a new ultrasonic monitoring approach using a combination of both linear and nonlinear spectral components. This was applied to high-throughput products and a dual frequency transducer designed and fabricated to acquire the ultrasonic backscattered signals in both the fundamental and second harmonic frequency regimes. The additional information provided by the harmonic device enabled discrimination between shampoo and conditioner products with the same density, but different molecular weights. HIFU transducer array designs are then considered for high power, low frequency chemical process enhancement applications. Typical applications of high power ultrasound use single or multiple discrete transducers to insonify a process. These are effective, but inflexible in the delivery of the ultrasonic field. The application of a HIFU array would provide control of the high power focal region in the load medium, which offer advantages to industry. Two transducer array approaches have been considered in this Thesis based on piezoelectric composite configurations. Three HIFU arrays based on the 1-3 piezocomposite have been fabricated to operate between 200-400kHz and fully characterised to evaluate their high power performance. A second transducer configuration was based on a novel 2-2 piezocomposite with a 2 layer stacked configuration. Simulation of this transducer design illustrated its potential for high power applications, although a number of fabrication issues resulted in the manufactured array not operating at full capacity. Importantly, the transducer configurations developed in this Thesis are shown to induce cavitation through the standard aluminium foil test.
11
Dhakal, Pratik. "EFFICIENT EARLY STAGE CHEMICAL PROCESS DESIGN". Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1533323971644795.
Pełny tekst źródła
12
Dearness, Wayne John. "Lubrication audit of chemical process plant". Thesis, Queensland University of Technology, 1999. https://eprints.qut.edu.au/36093/1/36093_Dearness_1999.pdf.
Pełny tekst źródłaStreszczenie:
A structured lubrication management model for the effective lubrication auditing of chemical
process plant has been developed, and is complemented in this report by a chemical process plant lubrication audit case study and field investigation that examines chronic long-term lubrication problems and failures of process plant machinery. The principal aim of this report is to increase the awareness of chemical process
industry personnel in identifying and resolving their lubrication requirements through effective long-term lubrication management. The report provides the vehicle and appropriate methods to identify, investigate and implement sound lubrication
management practices through lubrication auditing.
The benefits of lubrication management and the process of lubrication auditing outlined in the report pertain to the selection, purchase, storage, dispensing, use, disposal and control of lubricants . The lubrication audit benefits are often not recognised nor clearly understood by the majority of company staff, particularly those staff responsible for
plant lubrication. The potential exists for chemical process companies to raise the awareness of staff in lubrication related matters and increase plant efficiency, reliability and profitability through effective lubrication management practices identified by sound lubrication auditing.
13
Theruviparambil, Augustine Antony. "Reliability improvement of chemical process plant". Thesis, Queensland University of Technology, 1999. https://eprints.qut.edu.au/36094/1/36094_Theruviparambil_1999.pdf.
Pełny tekst źródłaStreszczenie:
When equipment acceptance procedures are ill-defined, or even neglected, customers are exposed to risks that may result in costly equipment failures. Use of well-defined acceptance procedures in an Equipment Acceptance Procedures Manual (EAPM) can be instrumental in reducing these risks. A case study was chosen to demonstrate how acceptance procedures could be instrumental in mitigating equipment failures before the equipment is introduced
into service. The acceptance procedures address design, manufacture and vibration audits of a refinery cooling tower fan gearbox. It is shown how recurrent failures of cooling tower fan gearboxes may have been avoided by
improvements to procurement procedures. During the process of the lubrication audit, it became evident that no information was available to estimate the gearbox power losses for gears rotating with their axes in the vertical lane. Hence, a simple experiment was designed to determine and evaluate the gearbox hydrodynamic power loss. The results of this experiment are compared with the data available for gears rotating about the horizontal axis and a relationship factor was determined
to evaluate the total hydrodynamic power losses quantitatively of the gearbox under consideration.
14
Lai, Sau Man. "Feasibility and flexibility in chemical process design /". View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20LAI.
Pełny tekst źródła
15
Iida, Kenji. "Systematic understanding of chemical process in solution". 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157607.
Pełny tekst źródła
16
Park, Jae-hyoung. "Process planning for laser chemical vapor deposition". Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/18367.
Pełny tekst źródła
17
Alqahtani, Abdullah. "Integrated approach to chemical process flowsheet synthesis". Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/4034.
Pełny tekst źródłaStreszczenie:
Chemical process synthesis is an open ended step of process design as it deals with the problem of how to develop and integrate the chemical process flowsheet. Over the past four decades, very few systematic procedures have been proposed for the rigorous synthesis of complete chemical process flowsheets. Mathematical design and heuristics from experience of past processes are the two main methods usually employed in process synthesis. Most approaches for new designs use heuristics based on studying reaction and separation systems in isolation. This thesis discusses the development of a new process synthesis systematic procedure and software that integrates a knowledge based system with Aspen HYSYS process simulator, HYSYS optimizer, Aspen Icarus economic evaluator, and databases, utilising knowledge from existing industrial processes to obtain design rules. The proposed generic superstructure for the synthesis and optimization of reaction-separation-recycle systems has been validated. To account for the non-ideal behaviour of reactors, modular simulation is used and an example of the approach is illustrated for a fluidized bed reactor. Preliminary work in customizing Aspen HYSYS to simulate new unit operation has been illustrated. A Visual Basic for Application (VBA) programming code has been developed to link the integrated knowledge based system (IKBS) to Aspen HYSYS. The prototype IKBS has been applied for the selection of reactor-separator-recycle systems for ethylene oxide, ethylene glycol, acetic acid and cumene manufacturing processes as case studies. A wide range of chemical reactors and separators were considered during the selection process and then elimination occurs at different levels leading to the best alternatives being selected for simulation, optimization and economic evaluation in the second phase of the IKBS for future development. The suggested alternative reactor-separator-recycle systems by the IKBS include currently used processes in addition to novel and recommended reactors/separators in industrial research. The proposed integrated knowledge based approach to chemical process flowsheet synthesis is expected to yield a cost effective design methodology for the petrochemical industry.
18
Papazoglou, Michael. "Multivariate statistical process control of chemical processes". Thesis, University of Newcastle Upon Tyne, 1998. http://hdl.handle.net/10443/408.
Pełny tekst źródłaStreszczenie:
The thesis describes the application of Multivariate Statistical Process Control (MSPC) to chemical processes for the task of process performance monitoring and fault detection and diagnosis. The applications considered are based upon polymerisation systems. The first part of the work establishes the appropriateness of MSPC methodologies for application to modern industrial chemical processes. The statistical projection techniques of Principal Component Analysis and Projection to Latent Structures are considered to be suitable for analysing the multivariate data sets obtained from chemical processes and are coupled with methods and techniques for implementing MSPC. A comprehensive derivation of these techniques are presented. The second part introduces the procedures that require to be followed for the appropriate implementation of MSPC-based schemes for process monitoring, fault detection and diagnosis. Extensions of the available projection techniques that can handle specific types of chemical processes, such as those that exhibit non-linear characteristics or comprise many distinct units are also presented. Moreover, the novel technique of Inverse Projection to Latent Structures that extends the application of MSPC-based schemes to processes where minimal process data is available is introduced. Finally, the proposed techniques and methodologies are illustrated by applications to a batch and a continuous polymerisation process.
19
Lawrence, Duncan. "Quantifying inherent safety of chemical process routes". Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/7427.
Pełny tekst źródłaStreszczenie:
Inherent safety is that which is intrinsic to a chemical plant. Chemical plants should be designed to be acceptably safe and it is better if this can be achieved through inherent safety, which can not be compromised, rather than engineered safety. The earlier that inherent safety is considered, the greater are the benefits. The choice of chemical route, that is the raw materials and the sequence of reactions that converts them to the desired products, is a key early design decision that influences the inherent safety of a plant. The inherent safety must be quantified in order to choose the optimum route from a number of alternatives. A trial inherent safety index has been developed for ranking alternative chemical routes by inherent safety. The physical properties of the chemicals involved, and the conditions in the reaction steps are parameters in the index calculation procedure. The index has been tested on a number of routes to methyl methacrylate (MMA). In order to verify and improve the index, a panel of experts was asked to rank the routes, and to make comments about the index and how it could be improved. This expert judgement exercise used three questionnaires and a group meeting to elicit the required information. Statistical methods were used to analyse the results from the questionnaires. The experts agreed closely among themselves on the rankings. The rankings from the trial index and the rankings from the experts matched closely. A new index was produced based on the comments of the experts and further research. The new index is more structured than the trial index, and separation and storage steps are included in addition to reaction steps. The inherent safety of the routes to MMA has been assessed with the new index. Developing a method for quantifying the inherent safety of chemical routes has proved to be a large and difficult task. Further research is needed to decide how the interactions between parameters affect the assessment of inherent safety. The ultimate goal is a computerised tool that could be used in the early stages of industrial process development.
20
Amar, Yehia. "Accelerating process development of complex chemical reactions". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288220.
Pełny tekst źródłaStreszczenie:
Process development of new complex reactions in the pharmaceutical and fine chemicals industries is challenging, and expensive. The field is beginning to see a bridging between fundamental first-principles investigations, and utilisation of data-driven statistical methods, such as machine learning. Nonetheless, process development and optimisation in these industries is mostly driven by trial-and-error, and experience. Approaches that move beyond these are limited to the well-developed optimisation of continuous variables, and often do not yield physical insights. This thesis describes several new methods developed to address research questions related to this challenge. First, we investigated whether utilising physical knowledge could aid statistics-guided self-optimisation of a C-H activation reaction, in which the optimisation variables were continuous. We then considered algorithmic treatment of the more challenging discrete variables, focussing on solvents. We parametrised a library of 459 solvents with physically meaningful molecular descriptors. Our case study was a homogeneous Rh-catalysed asymmetric hydrogenation to produce a chiral γ-lactam, with conversion and diastereoselectivity as objectives. We adapted a state-of-the-art multi-objective machine learning algorithm, based on Gaussian processes, to utilise the descriptors as inputs, and to create a surrogate model for each objective. The aim of the algorithm was to determine a set of Pareto solutions with a minimum experimental budget, whilst simultaneously addressing model uncertainty. We found that descriptors are a valuable tool for Design of Experiments, and can produce predictive and interpretable surrogate models. Subsequently, a physical investigation of this reaction led to the discovery of an efficient catalyst-ligand system, which we studied by operando NMR, and identified a parametrised kinetic model. Turning the focus then to ligands for asymmetric hydrogenation, we calculated versatile empirical descriptors based on the similarity of atomic environments, for 102 chiral ligands, to predict diastereoselectivity. Whilst the model fit was good, it failed to accurately predict the performance of an unseen ligand family, due to analogue bias. Physical knowledge has then guided the selection of symmetrised physico-chemical descriptors. This produced more accurate predictive models for diastereoselectivity, including for an unseen ligand family. The contribution of this thesis is a development of novel and effective workflows and methodologies for process development. These open the door for process chemists to save time and resources, freeing them up from routine work, to focus instead on creatively designing new chemistry for future real-world applications.
21
Nagel, Christopher John. "Identification of hazards in chemical process systems". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13952.
Pełny tekst źródła
22
Paulson, Joel Anthony. "Modern control methods for chemical process systems". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/109672.
Pełny tekst źródłaStreszczenie:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 301-322).
Strong trends in chemical engineering have led to increased complexity in plant design and operation, which has driven the demand for improved control techniques and methodologies. Improved control directly leads to smaller usage of resources, increased productivity, improved safety, and reduced pollution. Model predictive control (MPC) is the most advanced control technology widely practiced in industry. This technology, initially developed in the chemical engineering field in the 1970s, was a major advance over earlier multivariable control methods due to its ability to seamlessly handle constraints. However, limitations in industrial MPC technology spurred significant research over the past two to three decades in the search of increased capability. For these advancements to be widely implemented in industry, they must adequately address all of the issues associated with control design while meeting all of the control system requirements including: -- The controller must be insensitive to uncertainties including disturbances and unknown parameter values. -- The controlled system must perform well under input, actuator, and state constraints. -- The controller should be able to handle a large number of interacting variables efficiently as well as nonlinear process dynamics. -- The controlled system must be safe, reliable, and easy to maintain in the presence of system failures/faults. This thesis presents a framework for addressing these problems in a unified manner. Uncertainties and constraints are handled by extending current state-of-the-art MPC methods to handle probabilistic uncertainty descriptions for the unknown parameters and disturbances. Sensor and actuator failures (at the regulatory layer) are handled using a specific internal model control structure that allows for the regulatory control layer to perform optimally whenever one or more controllers is taken offline due to failures. Non-obvious faults, that may lead to catastrophic system failure if not detected early, are handled using a model-based active fault diagnosis method, which is also able to cope with constraints and uncertainties. These approaches are demonstrated on industrially relevant examples including crystallization and bioreactor processes.
by Joel Anthony Paulson.
Ph. D.
23
Mock, Theresa Lai-Hing. "Reducing process variability in chemical batch manufacturing". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12841.
Pełny tekst źródłaStreszczenie:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1992 and Thesis (M.S.)--Sloan School of Management, 1992.Includes bibliographical references (p. 145-148).
by Theresa Lai-Hing Mock.
M.S.
24
Smith, Fraser O. "Discontinuous flow analyser for process chemical analysis". Thesis, Queensland University of Technology, 1999.
Znajdź pełny tekst źródła
25
Joshi, R. R. "Simulation and optimization of chemical process plants". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2014. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2229.
Pełny tekst źródła
26
Shi, Ruijie. "Subspace identification methods for process dynamic modeling /". *McMaster only, 2001.
Znajdź pełny tekst źródła
27
Fung, Ka Yip. "Process development of specialty chemicals /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CENG%202006%20FUNG.
Pełny tekst źródła
28
Fisal, Zahedi B. "Real-time process plant fault diagnosis". Thesis, Aston University, 1989. http://publications.aston.ac.uk/9703/.
Pełny tekst źródłaStreszczenie:
Operators can become confused while diagnosing faults in process plant while in operation. This may prevent remedial actions being taken before hazardous consequences can occur. The work in this thesis proposes a method to aid plant operators in systematically finding the causes of any fault in the process plant. A computer aided fault diagnosis package has been developed for use on the widely available IBM PC compatible microcomputer. The program displays a coloured diagram of a fault tree on the VDU of the microcomputer, so that the operator can see the link between the fault and its causes. The consequences of the fault and the causes of the fault are also shown to provide a warning of what may happen if the fault is not remedied. The cause and effect data needed by the package are obtained from a hazard and operability (HAZOP) study on the process plant. The result of the HAZOP study is recorded as cause and symptom equations which are translated into a data structure and stored in the computer as a file for the package to access. Probability values are assigned to the events that constitute the basic causes of any deviation. From these probability values, the a priori probabilities of occurrence of other events are evaluated. A top-down recursive algorithm, called TDRA, for evaluating the probability of every event in a fault tree has been developed. From the a priori probabilities, the conditional probabilities of the causes of the fault are then evaluated using Bayes' conditional probability theorem. The posteriori probability values could then be used by the operators to check in an orderly manner the cause of the fault. The package has been tested using the results of a HAZOP study on a pilot distillation plant. The results from the test show how easy it is to trace the chain of events that leads to the primary cause of a fault. This method could be applied in a real process environment.
29
Heikkilä, Anna-Mari. "Inherent safety in process plant design : an index-based approach /". Espoo [Finland] : Technical Research Centre of Finland, 1999. http://www.vtt.fi/inf/pdf/publications/1999/P384.pdf.
Pełny tekst źródła
30
Vennapusa, Rami Reddy [Verfasser]. "Surface energetics of adsorbent-biomass interactions during expanded bed chromatography : implications for process performance / Rami Reddy Vennapusa". Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2009. http://d-nb.info/1034983792/34.
Pełny tekst źródła
31
Stuber, Matthew David. "Evaluation of process systems operating envelopes". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79143.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 229-238).
This thesis addresses the problem of worst-case steady-state design of process systems under uncertainty, also known as robust design. Designing for the worst case is of great importance when considering systems for deployment in extreme and hostile environments, where operational failures cannot be risked due to extraordinarily high economic and/or environmental expense. For this unique scenario, the cost of "over-designing" the process far outweighs the cost associated with operational failure. Hence, it must be guaranteed that the process is sufficiently robust in order to avoid operational failures. Many engineering, economic, and operations research applications are concerned with worst-case scenarios. Classically, these problems give rise to a type of leader-follower game, or Stackelberg game, commonly known as the "minimax" problem, or more precisely as a max-min or min-max optimization problem. However, since the application here is to steady-state design, the problem formulation results in a more general nonconvex equality-constrained min-max program, for which no previously available algorithm can solve effectively. Under certain assumptions, the equality constraints, which correspond to the steady-state model, can be eliminated from the problem by solving them for the state variables as implicit functions of the control variables and uncertainty parameters. This approach eliminates explicit functional dependence on the state variables, and in turn reduces the dimensionality of the original problem. However, this embeds implicit functions in the program, which have no explicit algebraic form and can only be approximated using numerical methods. By doing this, the max-min program can be reformulated as a more computationally tractable semi-infinite program, with the caveat that there are embedded implicit functions. Semi-infinite programming with embedded implicit functions is a new approach to modeling worst-case design problems. Furthermore, modeling process systems--especially those associated with chemical engineering--often results in highly nonconvex functions. The primary contribution of this thesis is a mathematical tool for solving implicit semi-infinite programs and assessing robust feasibility of process systems using a rigorous model-based approach. This tool has the ability to determine, with mathematical certainty, whether or not a physical process system based on the proposed design will fail in the worst case by taking into account uncertainty in the model parameters and uncertainty in the environment.
by Matthew David Stuber.
Ph.D.
32
Bird, Michael Roger. "Cleaning of food process plant". Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/251541.
Pełny tekst źródła
33
Stork, Christopher Lyle. "Monitoring chemical systems in the presence of process and analyzer variations /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/8670.
Pełny tekst źródła
34
Alici, Semra. "Dynamic data reconciliation using process simulation software and model identification tools". Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3025133.
Pełny tekst źródła
35
Heidebrecht, Peter [Verfasser]. "Model hierarchies for chemical process design / Peter Heidebrecht". Aachen : Shaker, 2011. http://d-nb.info/1069049441/34.
Pełny tekst źródła
36
Zhu, Jianye. "Integrated process design and control of chemical processes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/NQ34864.pdf.
Pełny tekst źródła
37
Porter, Richard Thomas James. "Kinetic mechanism reduction for chemical process hazard application". Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441227.
Pełny tekst źródła
38
Narisaranukul, Narintr. "Modeling and analysis of the chemical milling process". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43425.
Pełny tekst źródła
39
Hutton, Douglas. "Knowledge based flowsheet modelling for chemical process design". Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/15084.
Pełny tekst źródłaStreszczenie:
The aim of this work was to develop an experimental tool to perform flow-sheeting tasks throughout the course of chemical process design. Such design proceeds in a hierarchical manner increasing the amount of detail in the description of the plant, and, correspondingly, in the mathematical models used to describe the plant. The models range from the simplest overall mass balance to rigorous unit models, and the calculations required in the course of a design may include the modelling of the complete plant or any of its constituent parts at any level of detail between these two extremes. Object oriented programming has been used to represent the hierarchy of units required throughout a hierarchical design. A flexible modelling tool requires that models compatible with both the designer's intention and the context of the design are created. Sets of equations are defined in a generic form independent of process units with their selection as part of a model being dependent on the function and context of the unit being modelled. The expansion of the generic equation descriptions is achieved with reference to the structure of the unit, e.g. number of inlets and outlets, while the context of an equation determines the form of the equation to be applied, e.g. ideal or non-ideal behaviour. Equations are, therefore, represented as relations between a process item and its structural and contextual properties. An increase in modelling flexibility is obtained by allowing the designer to interact with generated models. Different sets of equations can be selected within constraints imposed by the system. At a lower level, terms in individual equations can be modified for particular applications. In chemical process design, many different analyses are performed. To demonstrate the application of different tools to a central model, the modelling system has been incorporated within a process synthesis framework. The application of the system to simple design case studies is described.
40
Xu, Dikai Xu. "Chemical Looping Partial Oxidation Process for Syngas Production". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503277899450895.
Pełny tekst źródła
41
Rawlings, Blake. "Discrete Dynamics in Chemical Process Control and Automation". Research Showcase @ CMU, 2016. http://repository.cmu.edu/dissertations/862.
Pełny tekst źródłaStreszczenie:
Formal verification has previously been applied to chemical plant control and automation systems to ensure that they operate as intended. This dissertation examines the related objective of proving that a particular control system does not operate as intended. To this end, we present a set of specifications that address certain aspects of the correct operation of a general control system. Some of those specifications, which relate to invariance and reachability of states that satisfy given logical constraints, do not fall within the classes of specifications that have been addressed in previous work related to the falsification of hybrid systems. For a specification from this class, a sound falsification algorithm is presented which can guarantee that a hybrid system does not meet the specification. The algorithm involves abstraction, as a finite-state discrete system, of the infinite-state hybrid dynamical system that arises when discrete control is applied to a continuous process. The falsification result relies on new results that we present which concern the supervisory control of discrete event systems subject to specifications that involve multiple reachability requirements. The methods we present are applied to two industrial case studies, which were provided by The Dow Chemical Company. We also present two software tools which apply the methods that we have developed. The first tool, SynthSMV, is an extension of the model checking solver NuSMV that can solve some supervisory control problems. NuSMV was chosen as the basis for our work in falsification because previous work has shown that its symbolic model checking algorithms can handle models of industrial-scale control systems in the context of verification. The second tool, st2smv, translates industrial control code to a formal model that can be solved using SynthSMV. The approach is similar to what has been done in previous work that focused on model checking and verification, with some extensions to enable the application of our work concerning supervisory control and falsification.
42
Taimoor, Aqeel Ahmad. "Biogas valorization for chemical industries via catalytic process". Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10243/document.
Pełny tekst źródłaStreszczenie:
La production de l'hydrogène à partir de biomasse est actuellement à l'étude mais la méthode de valorisation du biogaz (mélange H2/CO2) par réactions catalytiques, autres que la simple combustion, n'a pas encore été retenue. Par conséquent, le principal objectif de ce travail est d'explorer les autres voies. L'effet du CO2 sur le système catalytique est mal connu et seulement un effet négatif sur la dissociation de l'hydrogène a été mentionné. L'hydrogénation du toluène sur un catalyseur Pt a d'abord été étudiée sans CO2 pour suivre son comportement et éventuellement sa perte d'activité. En présence de CO2, l'inactivité complète du catalyseur pour l'hydrogénation du toluène a été mis en évidence. La modification de la surface du catalyseur par le CO2 est quantifiée par DRIFT et un mécanisme à deux sites a été montré. La réaction de Reverse Water Gas Shift produisant du CO se trouve être la principale cause de la désactivation de la surface de catalyseur avec le CO2. Donc la compétition d'adsorption entre le CO et des acides carboxyliques a été mise à profit pour favoriser sélectivement la conversion des acides. Pour l'alumine, elle est polluée par des carbonates complexes venant du CO2. La silice étant aussi connue pour promouvoir la décomposition, ces supports ont été rejetés. L'oxyde de titane a été utilisé pour catalyser une autre gamme de produits. Sur ce catalyseur, le changement de sélectivité entre le RWGS et la conversion de l'acide a été observé. Quant à l'oxyde de fer (catalyseur moins actif), il n’est pas capable de produire du CO à partir du CO2. La chimie de surface de l'oxyde de fer joue un rôle important sur la sélectivité du produit parmi les cétones et les aldéhydes. Un mécanisme à deux sites peut réutiliser pour l'oxyde de fer, montrant qu'un fonctionnement stable peut être trouvé si la réduction par l'hydrogène est continue. Si l'oxyde de fer est totalement oxydé par le CO2, produit de réaction, la production des cétones cesse. Énergiquement, le procédé de production d'acétone peut être autosuffisant et l'acétone peut être utilisée comme une molécule de stockage d'énergie. Le procédé va aussi compenser le nouveau procédé de production de phénol qui ne produit pas l'acétoneHydrogen potential from biomass is currently being studied but ways of valorization of such biogas (H2/CO2 mix) via catalytic reaction, other than simply burning has not yet been considered. Thus the main objective of this work is the exploration of such methods. Effect of CO2 over catalytic system was not well known and only hydrogen dissociation inhibition is reported. Toluene hydrogenation over Pt catalyst is studied and activity loss transition behavior is observed with no CO2 where as complete catalyst inactivity for toluene hydrogenation is found in presence of CO2. Catalyst surface change by CO2 is quantified by DRIFT analysis and two-site mechanism is found to prevail. Reverse water gas shift reaction producing CO is found to be the main cause behind such catalyst surface response to CO2. Adsorption competition between CO and carboxylic acids is exploited for selectivity shift in favor of acids conversion. Alumina support is fouled by carbonates complexes with CO2 while silica is reported to promote decomposition, thus both were rejected and titanium oxide is used instead with a range of products produced. The required selectivity shift between reverse water gas shift and acid conversion is thus observed. Less active iron oxide catalyst further suppresses CO2 conversion. Iron oxide surface chemistry plays an important role over product selectivity among ketones and aldehydes. Two sites mechanism still prevails over iron and stable continuous operation requires simultaneous iron reduction via hydrogen, if totally oxidized by CO2–a reaction product, will cease to produce ketones. Energetically the process devised for acetone production is self sufficient and acetone not only act as an energy storage molecule but can also compensate new phenol production process producing no acetone
43
de, Roulhac Selma Lee. "COMPARISON OF CHEMICAL PROCESS SIMULATION PROGRAMS FOR EDUCATION". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275282.
Pełny tekst źródła
44
Gomez, Giammattei Juan Alfredo. "Simultaneous optimization of a chemical process, its heat exchanger network, and the utility system using a process simulator". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11709.
Pełny tekst źródła
45
Dunn, Austin J. "Simulation and optimisation of industrial steam reformers. Development of models for both primary and secondary steam reformers and implementation of optimisation to improve both the performance of existing equipment and the design of future equipment". Thesis, University of Bradford, 2004. http://hdl.handle.net/10454/4403.
Pełny tekst źródłaStreszczenie:
Traditionally the reactor is recognised as the `heart' of a chemical process system and
hence the focus on this part of the system is usually quite detailed. Steam reforming,
however, due to the `building block' nature of its reaction products is unusual and
generally is perceived as a `utility' to other reaction processes and hence the focus is drawn " towards the 'main' reaction processes of the system. Additionally as a `mature' process,
steam reforming is often treated as sufficiently defined for the requirements within the
overall chemical process.
For both primary and secondary steam reformers several models of varying complexity
were developed which allowed assessment of issues raised about previous models and
model improvements; drawing on the advancements in modelling that have not only
allowed the possibility of increasing the scope of simulations but also increased confidence
in the simulation results. Despite the complex nature of the steam reforming systems, a
surprisingly simplistic model is demonstrated to perform well, however, to improve on
existing designs and maximise the capability of current designs it is shown that more
complex models are required.
After model development the natural course is to optimisation. This is a powerful tool
which must be used carefully as significant issues remain around its employment. Despite
the remaining concerns, some simple optimisation cases showed the potential of the models
developed in this work and although not exhaustive demonstrated the benefits of
optimisation.
46
Schug, Brett W. "Standardized modular process design with interval reasoning". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/10239.
Pełny tekst źródła
47
Pore, Mridula. "Pharmaceutical tablet compaction : product and process design". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/51623.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2009.Includes bibliographical references.
This thesis explores how tablet performance is affected by microstructure, and how microstructure can be controlled by selection of excipients and compaction parameters. A systematic strategy for formulation and process design of pharmaceutical tablets is proposed. A modified nanoindenter method was used to test the mechanical behavior of diametrally compressed excipient granules. X ray micro computed tomography and Terahertz pulsed spectroscopy (TPS) and imaging (TPI) were used to analyze the microstructure of the tablet core and detect internal defects. Granule failure mechanisms are found to be consistent with tablet microstructure. MCC granules deform plastically when tested and X ray images show individual granules undergoing increasing deformation in tablets as higher compaction forces are used. A highly interconnected pore-structure limited tablet hardness and led to bursting behavior during dissolution. No effect of compaction force or speed was observed in dissolution profiles. Lactose granules fracture at strains less than 5%, forming monolithic structures with no evidence of initial granule shape or size. Pore size decreases as compaction force is increased for DCL 11 tablets. A decreasing pore size corresponds to increasing THz refractive index, tablet hardness and dissolution time. DCL 11 and DCL 14 tablets compacted under the same conditions have the same pore size distributions and hardness, although DCL 14 granules are weaker than DCL 11, and DCL 14 tablets dissolve up to four times slower than DCL 11 tablets. No difference was observed between the THz spectra of tablets made from the two grades of lactose.
(cont.) Further work is needed to understand the physical significance of the THz measurements. TPI can detect laminated tablets and is faster than X ray micro CT. In order to develop a rational design methodology, two key areas for future research are building a process model for compaction and developing quality testing methods that can be analyzed mechanistically. The capstone project explores strategic decision making for innovator firms and generic drug manufacturers in the period surrounding patent expiry. Statin products were used as an illustrative case of a pharmaceutical technology experiencing commoditization. A system dynamics model was used to simulate historic results and explore options for products still under patent protection. Current models of technology market dynamics apply to statins, but regulation and legislation play a large role in controlling market entry, leading to strong sequencing effects.
by Mridula Pore.
Ph.D.
48
Abel, Matthew J. "Process systems engineering of continuous pharmaceutical manufacturing". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/58446.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 290-299).
Continuous manufacturing offers a number of operational and financial benefits to pharmaceutical companies. This research examines the critical blending step for continuous pharmaceutical manufacturing and the characteristics of continuous downstream pharmaceutical manufacturing systems. Discrete element method (DEM) simulations were used to develop novel insights into the mechanism of mixing for continuous blending of cohesive pharmaceutical powders and to examine the effects of particle properties, blender design and operating conditions on blend homogeneity. To place continuous blending into the context of pharmaceutical manufacturing, the scope of the analysis was expanded to process system models of continuous downstream pharmaceutical manufacturing. DEM simulations were used to study the mechanisms of mixing in the continuous blending of pharmaceutical powders. Diffusive mixing from the avalanching particles appears to be the dominant mechanism of mixing in both the axial and radial direction for the double helical ribbon blender. This result can guide the development of future continuous pharmaceutical powder blenders by optimizing the mixing elements to increase the amount of particles transported to a position where they can avalanche/flow and diffusively mix. A range of particle properties, blender designs and operating conditions were examined for their effects on flow behavior and blend homogeneity. Three particle properties were examined: particle size, polydispersity and cohesive force.
(cont.) Particle size was observed to be positively correlated to both flow rates and blend homogeneity. Polydispersity had no effect on flow rate and was negatively correlated to homogeneity. Cohesive force was negatively correlated to flow rate and had little to no effect on homogeneity. Two modifications of blender design were analyzed: changes in blender size and changes in shaft design. Blender size was observed to be positively correlated to flow rate and negatively correlated to homogeneity. The paddle shaft designs created a more homogeneous powder blend than the double helical ribbon shaft. Two operating parameters were also studied: rotation rate and fill fraction. Rotation rate was positively correlated to both flow rate and homogeneity. Fill fraction had the interesting result of being positively correlated to the absolute flow rate, but negatively correlated to the fill mass normalized flow rate. In addition, fill fraction has a clear negative correlation to homogeneity above fill fractions of 0.55, but is inconsistent for fill fractions lower than this. This research on particle properties, blender designs and operating conditions will help to guide the operation of continuous pharmaceutical blenders and the design of continuous pharmaceutical manufacturing systems. Process simulations comparing model batch and continuous downstream pharmaceutical manufacturing systems have quantified some of the potential size, cost and performance benefits of continuous processes. The models showed significant reductions in process equipment sizes for continuous manufacturing particularly in the blending step.
(cont.) This reduction in equipment size translates to capital cost (CAPEX) savings for both the continuous process equipment and manufacturing facilities. The steady state operation of continuous processing also reduces the labor requirements and gives the continuous processes an operating cost (OPEX) advantage over batch processes. This research has contributed to the understanding of continuous pharmaceutical powder blending and quantified some of the benefits of continuous downstream pharmaceutical manufacturing. This work is being continued by the Novartis-MIT Center for Continuous Manufacturing whose work is providing the foundation for future industrial scale pharmaceutical continuous manufacturing systems.
by Matthew J. Abel.
Ph.D.
49
Sinangil, Mehmet Selcuk. "Modeling and control on an industrial polymerization process". Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/10150.
Pełny tekst źródła
50
Cornell, Ann. "Electrode reactions in the chlorate process". Doctoral thesis, KTH, Kemiteknik, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3442.
Pełny tekst źródła