Home About us Contact
|
Home About us Contact | ||
|
|
||
Control Technologies (control + technology)
Selected AbstractsEvolution of hazardous waste combustors MACT standardsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2001Charles W. Lamb Ph.D. This year, on July 24, the DC Circuit Court ruled that the EPA had not correctly derived emission standards, and vacated the MACT (Maximum Achievable Control Technology) rule for Hazardous Waste Combustors (HWC) [1, 2]. A major complaint, voiced by the Sierra Club, was that the MACT methodology was misapplied in a manner that produced overly lenient standards. Industry and trade associations argued just the opposite. The Sierra Club won the first round when the court agreed that the emission standards should be based on the average of the best-performing 12% of units in each category. The next question was, "What will be the regulations until the final standards can be developed?" This caused considerable angst because, if no standards were in place by May 15, 2002, control would revert to case-by-case permits by Federal and State regulatory agencies as set forth in Section 112 of the Clean Air Act. Obviously, that would be the antithesis of the Congressional mandate and the objectives of environmental groups. The Sierra Club and most litigants did not want the uncertainties and inconsistencies this would introduce. [source] Feedback control design for an anaerobic digestion processJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002Jose Alvarez-Ramirez Abstract An approach for the design of linear feedback controllers for anaerobic digestion systems is presented. The effluent chemical oxigen demand (COD) concentration and the dilution rate are taken respectively as the regulated and the manipulated variables. The control design is based on simple step-response models of the process endowed with an input delay to account for dead-times induced by measurement devices. The resulting feedback controller has a traditional proportional-integral (PI) control structure, so it can be easily implemented with conventional control technologies. Since the concentration of volatile fatty acids can be easily and quickly measured as compared with COD concentration, it is used as a secondary measurement that is incorporated into the feedback loop scheme to enhance the robustness of the control scheme with respect of influent disturbances. The performance of the proposed control scheme is illustrated via numerical simulations and experimental work. © 2002 Society of Chemical Industry [source] Comprehensive process design study for layered-NOX -control in a tangentially coal fired boilerAICHE JOURNAL, Issue 3 2010Wei Zhou Abstract As emissions regulations for coal-fired power plants become stricter worldwide, layering combustion modification and post-combustion NOX control technologies can be an attractive option for efficient and cost-effective NOX control in comparison to selective catalytic reduction (SCR) technology. The layered control technology approach designed in this article consists of separate overfire air (SOFA), reburn, and selective noncatalytic reduction (SNCR). The combined system can achieve up to 75% NOX reduction. The work presented in this article successfully applied this technology to NRG Somerset Unit 6, a 120-MW tangential coal-fired utility boiler, to reduce NOX emissions to 0.11 lb/MMBtu (130 mg/Nm3), well under the US EPA SIP Call target of 0.15 lb/MMBtu. The article reviews an integrated design study for the layered system at Somerset and evaluates the performance of different layered-NOX -control scenarios including standalone SNCR (baseline), separated overfire air (SOFA) with SNCR, and gas reburn with SNCR. Isothermal physical flow modeling and computational fluid dynamics simulation (CFD) were applied to understand the boiler flow patterns, the combustible distributions and the impact of combustion modifications on boiler operation and SNCR performance. The modeling results were compared with field data for model validation and verification. The study demonstrates that a comprehensive process design using advanced engineering tools is beneficial to the success of a layered low NOX system. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Interfirm Innovation under Uncertainty: Empirical Evidence for Strategic Knowledge Partitioning,THE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 5 2008Jaegul Lee This paper analyzes how uncertainty and life-cycle effects condition the knowledge boundary between assemblers and suppliers in interfirm product development. Patents associated with automotive emission control technologies for both assemblers and suppliers are categorized as architectural or component innovations, and technology-forcing regulations imposed by the government on the auto industry from 1970 to 1998 are used to define periods of high and low uncertainty. Results confirm that suppliers dominate component innovation whereas assemblers lead on architectural innovation. More importantly, when facing uncertainty firms adjust their knowledge boundary by increasing the knowledge overlap with their supply-chain collaborators. Suppliers clearly expand their knowledge base relatively more into architectural knowledge during such periods. But assemblers' greater emphasis on component innovation in periods of greater uncertainty is only true as a relative deviation from an overall trend toward increasing component innovation over time. This trend results from an observed life-cycle effect, whereby architectural innovation dominates before the emergence of a dominant design, with component innovation taking the lead afterward. Thus, for assemblers life-cycle effects may dominate over task uncertainty in determining relative effort in component versus architectural innovation. This work extends research on strategic interfirm knowledge partitioning as well as on the information-processing view of product development. First, it provides a large-scale empirical justification for the claim that firms' knowledge boundaries need to extend beyond their task boundaries. Further, it implies that overlaps in knowledge domains between an assembler and suppliers are particularly important for projects involving new technologies. Second, it offers a dynamic view of knowledge partitioning, showing how architectural knowledge prevails in the early phase of the product life cycle whereas component knowledge dominates the later stages. Yet the importance of life-cycle effects versus task uncertainty in conditioning knowledge boundaries is different for assemblers and suppliers, with the former dominating for assemblers and the latter more influential for suppliers. Finally, it supports the idea that architectural and component knowledge are critical elements in the alignment of cognitive frameworks between assemblers and suppliers and thus are key for information-exchange effectiveness and resolution of task uncertainties in interfirm innovation. [source] Online-Analytik zur Prozessführung,CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 10 2004G. Dünnebier Dr. Abstract Sichere, leistungsfähige und damit auch wirtschaftlich optimale Prozessführung in der chemischen Industrie ist mehr denn je auf Messdaten aus den betreffenden Prozessen angewiesen. Zunehmend werden zur Regelung stoffspezifische Informationen, z.,B. Sätze von Einzelstoffkonzentrationen, eingesetzt. Die Online-Analytik birgt in Kombination mit Prozessführung ein enormes wirtschaftliches Potenzial. Es ist jedoch ein steiniger Weg, der zur Ausschöpfung dieses wirtschaftlichen Potenzials führt, weshalb die Zahl der realisierten Anwendungen erst in den letzten Jahren stetig wächst. Der zentrale Teil dieses Beitrags veranschaulicht an Beispielen die Möglichkeiten, Online-Analytik und Prozessführung zu kombinieren, u.,a. anhand einer Batch-Destillationskolonne, einer kontinuierlichen destillativen Isomerentrennung sowie der Automatisierung einer kompletten Feinchemieanlage. Aus den Erfahrungen und Problemen der bisherigen Projekte lassen sich Wünsche und Regeln sowohl für die Definition und Abwicklung solcher Projekte in einem interdisziplinären Team als auch für die systemtechnische Anbindung der Online-Analytik an das Leitsystem ableiten. Online Analyzers for the Process Control Save, efficient, and economical operation of chemical processes more and more relies on online analyzers. The use of component properties (e.g., concentrations) for control becomes even more common. The combination of online analyzers and advanced control technologies holds an enormous economic potential, though a rocky path is leading there. As a result the number of existing applications is only growing slowly, but steadily. The main part of this contribution shows the potential of the combination of advanced control technologies and online analyzers using some illustrative examples like a batch distillation column, a continuous isomer distillation unit and the automation of a complete fine chemicals unit. Based on the experiences and problems encountered in the past projects, some guidelines and requests are formulated to optimize the definition and implementation of these projects in an interdisciplinary team and the integration of the online analyzers in a distributed control system. [source] Recovery of CO2 with MEA and K2CO3 absorption in the IGCC systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2004Baoqun Wang Abstract Recovery of CO2 with monoethanolamine (MEA) and hot potassium carbonate (K2CO3) absorption processes in an integrated gasification combined cycle (IGCC) power plant was studied for the purpose of development of greenhouse gas control technology. Based on energy and exergy analysis of the two systems, improvement options were provided to further reduce energy penalty for the CO2 separation in the IGCC system. In the improvement options, the energy consumption for CO2 separation is reduced by about 32%. As a result, the thermal efficiency of IGCC system is increased by 2.15 percentage-point for the IGCC system with MEA absorption, and by 1.56 percentage-point for the IGCC system with K2CO3 absorption. Copyright © 2004 John Wiley & Sons, Ltd. [source] A simple and low-cost solution for the automation of X-ray powder diffractometers with chart recorder outputJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2006M. Jayaprakasan X-ray powder diffraction is an established method for the qualitative identification of crystalline materials and their quantitative analysis. The new generation of X-ray diffraction systems are based on expensive digital/embedded control technology and computer interfaces. Yet many laboratories use conventional manual-controlled systems with XY strip-chart recorders. Since the output spectrum is a strip chart (hard copy), raw data, essential for structural and qualitative analysis, are not readily available for further analysis. Upgrading to modern computerized diffractometers is very expensive. The proposed automation design described here is intended to enable the conventional diffractometer user to collect, store and analyze data quickly. The design also improves the resolution by five times compared with the conventional setup. For the automation, a PC add-on card has been designed to control and collect the timing and intensity counts from the conventional X-ray diffractometer, and suitable software has been developed to collect, process and present the X-ray diffraction data for both qualitative and quantitative analysis. Moreover, a major advantage of this design is that it does not warrant any physical modification of the hardware of the conventional setup; it is simply an extension to enhance the performance of collecting raw data with a higher resolution at desired intervals/timings. [source] Projective virtual reality as a basis for on-line control of complex systems-not only-over the internetJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2005Eckhard Freund Already in 1994 the term Projective Virtual Reality was coined and a first implementation was used to control a complex multirobot system in Germany over the Internet from California. Building on this foundation, the general aim of the development of virtual reality technology for automation applications at the Institute of Robotics Research (IRF) today is to provide the framework for Projective Virtual Reality for a broad range of applications. The general idea of Projective Virtual Reality is to allow users to "project" actions carried out in the virtual world into the real world by means of robots or other means of automation. The framework is based on a task-oriented approach which builds on the "task deduction" capabilities of a newly developed virtual reality system and a task planning component. The advantage of this approach is that robots which work at great distances from the control station can be controlled as easily and intuitively as robots that work right next to the control station. Robot control technology now provides the user in the virtual world with a "prolonged arm" into the physical environment, thus paving the way for intuitive control of complex systems over the Internet,and in general for a new quality of user-friendly man-machine interfaces for automation applications. Lately, this work has been enhanced by a new structure that allows one to distribute the virtual reality application over multiple computers on a network. With this new feature, it is now possible for multiple users to share the same virtual room, although they may physically be thousands of miles apart. They only need an Internet connection to share this new experience. Lately, the network distribution techniques have been further developed to not just allow users to cooperate over networked PCs but also to be able to set up a panorama projection or a cave running of a networked cluster of PCs. This approach cuts down the costs for such a high-end visualization environment drastically and allows for a new range of applications. © 2005 Wiley Periodicals, Inc. [source] Industrial perspectives of AFM controlASIAN JOURNAL OF CONTROL, Issue 2 2009Chanmin Su Abstract The controllers delivered by atomic force microscope (AFM) manufacturers to AFM users are several decades behind various advanced control technology. This paper is trying to analyze factors that created this gap to reach certain specifications, either quantitatively or qualitatively, of an ideal controller viewing from AFM industries. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Hazardous air pollutants emission from coal and oil-fired power plantsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Deepak Pudasainee Abstract Hazardous air pollutants (HAPs) emission characteristics from coal (anthracite, bituminous) and oil-fired power plants were studied in order to control pollutants by formulating US maximum achievable control technology (MACT)-like regulation in Korea. Sampling and analysis were carried out according to either Korean standard test method or US EPA method. Relatively lower levels of NOx and SOx were emitted from plants burning bituminous than the anthracite coal. Less dust was emitted from oil-fired power plants. Mercury, lead, and chromium were dominant in coal-fired power plants, following which, nickel and chromium were emitted from oil-fired power plants. The major volatile organic compounds (VOCs) emitted from coal-fired plants were 1,2-dichloroethane, benzene, carbon tetrachloride, chloroform, trichloro-ethylene. The emission of mercury and other heavy metals in flue gas was attributed to fuel types, operating conditions, residence time in the control devices and air pollution control devices configuration. After emission tests in the field and on analysis of the continuous emission monitoring data collected from facilities under operation and consideration of other various factors, management guidelines will be suggested with special reference to US MACT-like regulation. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Advanced and intelligent technologies for reliable operation of power systems and electricity marketsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 5 2008Ryuichi Yokoyama Senior Member Abstract Deregulation of power industries is still progressing in many countries, aiming at reduction of the electricity price, diversity of customer diverse choices, services and promotion of new business and keeping supply reliability. Many countries are testing this notion in anticipation of lower power prices through open competition. In such a competitive situation, it is necessary for suppliers to take on the responsibility of keeping supply reliability at the load end in order to prevent outages, for instance, independent power producers (IPP) placing distributed generations (DGs) close to the load or conventional utilities utilizing advanced and intelligent system operation/control technologies that are costly. Usually, customers pay one price for power that is good enough for ordinary use, therefore not necessarily highly consistent in quality of voltage, current, frequency or reliability. However, if customers desire better quality power, additional fees are added according to the particular characteristics desired, thus customers are supplied with this type of better power that they choose. Under such a worldwide new trend in power systems and markets, this article is edited for the purpose of introducing the most advanced technologies and the newest issues related to reliable and stable operations of power markets and systems in the competitive environment. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] | |||||||||||||