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Books > Professional & Technical > Industrial chemistry & manufacturing technologies > Industrial chemistry > General
Dry sulfurization processes offer the significant advantages of low capital and low operating costs when compared to wet desulfurization. They hold great potential for the economical reduction of sulfur emissions from power utilities that use high-sulfur coal. Dry Scrubbing Technologies for Flue Gas Desulfurization represents a body of research that was sponsored by the State of Ohio's Coal Development Office for the development of technologies that use coal in an economic, environmentally-sound manner. One of the project's major goals was the development of dry, calcium-based sorption processes for removing sulfur dioxide from the combustion gases produced by high-sulfur coal. Dry Scrubbing Technologies for Flue Gas Desulfurization highlights a number of fundamental research findings that have had a significant and lasting impact in terms of scientific understanding. For example, the experimental investigation of the upper-furnace sulfur capture obtained time-resolved kinetic data in less than 100 millisecond time-scales for the first time ever, thereby revealing the true nature of the ultra-fast and overlapping phenomena. This was accomplished through the development of a unique entrained flow reactor system. The authors also identify a number of important areas for future research, including reaction mechanisms, sorbent material, transport effects, modeling, and process development. Dry Scrubbing Technologies for Flue Gas Desulfurization will appeal to both chemical and environmental engineers who examine different ways touse coal in a more environmentally benign manner. It will make an essential reference for air pollution control researchers from coal, lime, cement, and utility industries; for government policy-makers and environmental regulatory agencies; and for those who teach graduate courses in environmental issues, pollution control technologies, and environmental policy.
Metal-Oxygen Clusters is the first book, providing an overview of the surface chemistry and catalytic properties of heteropoly oxometalates. After a brief look at the early knowledge of heteropoly oxometalates, the book discusses the synthesis, characterization, structure, bulk properties and stability of these materials. The remainder and the largest portion of the book explores the properties of these solids as catalysts in acid-catalyzed and oxidation processes in supported or unsupported forms. The book provides an up-to-date review of the methods for synthesizing heteropoly oxometalates of Keggin structure, techniques from spectroscopic through electrochemical to elemental analysis for their characterization and the current information on their structure, bulk properties and their stabilities at high temperatures and under acid and alkaline conditions. The book discusses the materials employed as supports for the title solid and the results of the examination of the supported materials. Methods for the identification of the nature and source of the two catalytic functions, the acidic and oxidative properties, of the heteropoly oxometalates are reviewed and discussed. The use of both the supported and unsupported heteropoly oxometalates as catalysts in acidity-requisite processes ranging from methanol conversion to hydrocarbons to ring-expansion and contraction processes and in oxidation processes from methane cyclohexane are described and related to the aforementioned properties.
It may be argued that silicon, carbon, hydrogen, oxygen, and iron are among the most important elements on our planet, because of their involvement in geological, biol- ical, and technological processes and phenomena. All of these elements have been studied exhaustively, and voluminous material is available on their properties. Included in this material are numerous accounts of their electrochemical properties, ranging from reviews to extensive monographs to encyclopedic discourses. This is certainly true for C, H, O, and Fe, but it is true to a much lesser extent for Si, except for the specific topic of semiconductor electrochemistry. Indeed, given the importance of the elect- chemical processing of silicon and the use of silicon in electrochemical devices (e. g. , sensors and photoelectrochemical cells), the lack of a comprehensive account of the electrochemistry of silicon in aqueous solution at the fundamental level is surprising and somewhat troubling. It is troubling in the sense that the non-photoelectrochemistry of silicon seems "to have fallen through the cracks," with the result that some of the electrochemical properties of this element are not as well known as might be warranted by its importance in a modern technological society. Dr. Zhang's book, Electrochemical Properties of Silicon and Its Oxide, will go a long way toward addressing this shortcoming. As with his earlier book on the elect- chemistry of zinc, the present book provides a comprehensive account of the elect- chemistry of silicon in aqueous solution.
Corinna Reisinger has developed a new organocatalytic asymmetric epoxidation of cyclic and acyclic , -unsaturated ketones. In this thesis, Corinna documents her methodology, using primary amine salts as catalysts, and hydrogen peroxide as an inexpensive and environmentally benign oxidant. She describes the unprecedented and powerful catalytic asymmetric hydro peroxi dation of , -enones, a process which produces optically active five-membered cyclic peroxyhemiketals in a single operation. She also proves the versatility and synthetic value of the cyclic peroxyhemiketals by converting them into highly enantioenriched acyclic and cyclic aldol products. Currently, these cyclic aldol products are inaccessible by any other synthetic means. Furthermore, cyclic peroxyhemiketals are precursors to optically active 1,2-dioxolanes which are of biological relevance. This work is a breakthrough in the field of asymmetric epoxidation chemistry and outlines the most efficient method in the literature for generating highly enantioselective cyclic epoxyketones known to date.
One of the most significant challenges facing mankind in the twenty-first century is the development of a sustainable global economy. Within the scientific community, this calls for the development of processes and technologies that will allow the sustainable production of materials from renewable natural resources. Plant material, in particular lignin, is one such resource. During the annual production of about 100 million metric tons of chemical wood pulps worldwide, approximately 45 and 2 million metric tons/year of kraft lignin and lignosulfonates, respectively, are also generated. Although lignosulfonates have found many applications outside the pulp and paper industry, the majority of kraft lignin is being used internally as a low-grade fuel for the kraft pulping operation. A surplus of kraft lignin will become available as kraft mills increase their pulp production without expanding the capacity of their recovery boilers that utilize lignin as a fuel. There is a tremendous opportunity and an enormous economic incentive to find better uses of kraft lignin, lignosulfonates and other industriallignins. The pulp and paper industry not only produces an enormous amount of lignins as by products of chemical wood pulps, but it also utilizes about 10 million metric tons of lignin per year as a component of mechanical wood pulps and papers. Mechanical wood pulps, produced in a yield of 90-98% with the retention of lignin, are mainly used to make low-quality, non-permanent papers such as newsprint and telephone directories because of the light-induced photooxidation of lignin and the yellowing of the papers.
Multiphase reactors are becoming an important subject as a result of numerous applications in various fields ranging from chemical and petrochemical to food, biological and pharmaceutical (FBPl en gineering, namely in the hydrodesulfurization of petroleum, produc tion of antibiotics and wastewater treatment. The importance of the subject is measured by the increasing num ber of publications and meeting sections dedicated to it. Therefore an Advanced Study Institute on Multiphase Chemical Reactors was held in Vimeiro, Portugal from 18 to 30 August 1980, following an International Symposium on Chemical Engineering of Gas-Liquid-Solid Catalyst Reactions, held in Liege, 1978. The purpose of this NATO ASI was to present a didacted approach to multiphase reactor design, through the interaction among hydro dynamics, reaction and transport processes. The lectures delivered there are compiled in two volumes. In the first volume an overview of the field is presented, followed by a detailed analysis of the fundamental concepts (interphase mass transfer models, mass transfer with chemical reaction, theory of residence time distributions and micromixing phenomenal.Numerical methods are often required to solve the mathematical models involved; so a chapter is dedicated to this subject followed by a discussion of steady-state multiplicity and stability. Finally, a section with special applications of multiphase reactors is included, presenting topics on biological reactors, emulsion po lymerization, supported liquid phase catalyst and enhanced oil re- VI covery."
In recent years, the technology of cryogenic comminution has been widely applied in the field of chemical engineering, food making, medicine production, and particularly in recycling of waste materials. Because of the increasing pollution of waste tires and the shortage of raw rubber resource, the recycling process for waste rubber products has become important and commercially viable. This technology has shown a great number of advantages such as causing no environmental pollution, requiring low energy consumption and producing high quality products. Hence, the normal crusher which was used to reclaim materials, such as waste tires, nylon, plastic and many polymer materials at atmospheric 12 temperature is being replaced by a cryogenic crusher. * In the cryogenic crusher, the property of the milled material is usually very sensitive to temperature change. When a crusher is in operation, it will generate a great deal of heat that causes the material temperature increased. Once the temperature increases over the vitrification temperature, the material property will change and lose the brittle behavior causing the energy consumption to rise sharply. Consequently, the comminution process cannot be continued. Therefore, it is believed that the cryogenic crusher is the most critical component in the cryogenic comminution system. The research on the temperature increase and energy consumption in the cryogenic crusher is not only to reduce the energy consumption of the crasher, but also to reduce the energy consumption of the cryogenic system.
Among the most promising techniques to handle small objects at the micrometer scale are those that employ electrical forces, which have the advantages of voltage-based control and dominance over other forces. The book provides a state-of-the-art knowledge on both theoretical and applied aspects of the electrical manipulation of colloidal particles and fluids in microsystems and covers the following topics: dielectrophoresis, electrowetting, electrohydrodynamics in microsystems, and electrokinetics of fluids and particles. The book is addressed to doctoral students, young or senior researchers, chemical engineers and/or biotechnologists with an interest in microfluidics, lab-on-chip or MEMS.
An apparently appropriate control scheme for PEM fuel cells may actually lead to an inoperable plant when it is connected to other unit operations in a process with recycle streams and energy integration. PEM Fuel Cells with Bio-Ethanol Processor Systems presents a control system design that provides basic regulation of the hydrogen production process with PEM fuel cells. It then goes on to construct a fault diagnosis system to improve plant safety above this control structure. PEM Fuel Cells with Bio-Ethanol Processor Systems is divided into two parts: the first covers fuel cells and the second discusses plants for hydrogen production from bio-ethanol to feed PEM fuel cells. Both parts give detailed analyses of modeling, simulation, advanced control, and fault diagnosis. They give an extensive, in-depth discussion of the problems that can occur in fuel cell systems and propose a way to control these systems through advanced control algorithms. A significant part of the book is also given over to computer-aided engineering software tools that can be used to evaluate the dynamic performance of the overall plant. PEM Fuel Cells with Bio-Ethanol Processor Systems is intended for use by researchers and advanced students on chemical, electrical-electronic and mechanical engineering courses in which dynamics and control are incorporated with the traditional steady-state coverage of flowsheet synthesis, engineering economics and optimization.
This thesis details the significant progress made in improving the performance of organic transistors and the network conductivity of carbon nanotubes. The first section investigates organic semiconductor nucleation and growth on the most common dielectric surface used to fabricate organic thin film transistors. The nucleation and growth of the semiconductor was determined to be a critical factor affecting the device performance. Excellent dielectric modification layers, which promote desirable semiconductor growth leading to high conductivity were identified, and a technologically relevant deposition technique was developed to fabricate high quality dielectric modification layers over large areas. This may represent an important step towards the realization of large area organic circuity. In the final section, lessons learned from studying organic semiconductor nucleation and growth were utilized to improve the conductivity of carbon nanotube networks. Selective nucleation of materials at the junctions between nanotubes in the network significantly decreased the network's sheet resistance. The resulting networks may be promising candidates for transparent electrodes with a variety of optoelectronic applications.
A thermodynamically consistent description of the transport across interfaces in mixtures has for a long time been an open issue. This research clarifies that the interface between a liquid and a vapor in a mixture is in local equilibrium during evaporation and condensation. It implies that the thermodynamics developed for interfaces by Gibbs can be applied also away from equilibrium, which is typically the case in reality. A description of phase transitions is of great importance for the understanding of both natural and industrial processes. For example, it is relevant for the understanding of the increase of CO2 concentration in the atmosphere, or improvements of efficiency in distillation columns. This excellent work of luminescent scientific novelty has brought this area a significant step forward. The systematic documentation of the approach will facilitate further applications of the theoretical framework to important problems.
Control of Integral Processes with Dead Time provides a unified and coherent review of the various approaches devised for the control of integral processes, addressing the problem from different standpoints. In particular, the book treats the following topics: How to tune a PID controller and assess its performance; How to design a two-degree-of-freedom control scheme in order to deal with both the set-point following and load disturbance rejection tasks; How to modify the basic Smith predictor control scheme in order to cope with the presence of an integrator in the process; and how to address the presence of large process dead times. The methods are presented sequentially, highlighting the evolution of their rationale and implementation and thus clearly characterising them from both academic and industrial perspectives.
The increasing global demand for energy requires a versatile approach, prompting many researchers to focus on renewable bioenergy from different biomasses, especially cellulosic biomass. Such biomasses can be agricultural wastes, municipal wastes or direct harvests from high-yield energy corps. If properly pre-treated, the subsequent enzyme hydrolysis step is much more effective and can effectively minimises the waste disposal. "Green Biomass Pretreatment for Biofuels Production " reviews a range of pretreatment methods such as ammonium fiber explosion, steam explosion, dilute acid hydrolysis, alkali hydrolysis, and supercritical carbon dioxide explosion focusing on their final sugar yields from hemicellulose, glucose yields from cellulose, as well as on their feasibilities in bioenergy production processes at various scales. This book emphasises the tactical mobile and on-farm scales applications that use green pretreatments and processing technologies without the need of on-site waste treatment. Because of the varieties of different biomasses, no single pretreatment is expected to be the universal choice. Some of the pretreatment methods present niche applications are also discussed.
Ruthenium Oxidation Complexes explores ruthenium complexes, particularly those in higher oxidation states, which function as useful and selective organic oxidation catalysts. Particular emphasis is placed on those systems which are of industrial significance. The preparation, properties and applications of the ruthenium complexes are described, followed by a presentation of their oxidative properties and summary of the different mechanisms involved in the organic oxidations (e.g. oxidations of alcohols, alkenes, arenes and alkynes, alkanes, amines, ethers, phopshines and miscellaneous substrates). Moreover, future trends and developments in the area are discussed. This monograph is aimed at inorganic, organic, industrial and catalysis chemists, especially those who wish to carry out specific organic oxidations using catalytic methods.
Since 1971 when useful working concepts for the technique of phase-transfer catalysis (PTC) were introduced, the understanding, development, and applica tions of this method for conducting organic reactions has expanded exponentially. PTC has brought vast new dimensions and options to chemists and chemical engineers. From its use in less than ten commercial processes in 1975, PTC use has increased so that in the early 1990s it is involved in more than 600 industrial applications to manufacture products valued at between 10 and 20 billion U.S. dollars. PTC is widely used for simple organic reactions, steps in synthesis of pharmaceuticals, agricultural chemicals, perfumes, ftavorants, and dyes; for specialty polymerization reactions, polymer modifications, and monomer synthe sis; for pollution and environmental control processes; for analysis oftrace organic and inorganic compounds; and for many other applications. Often, PTC offers the best (and sometimes only) practical technique to obtain certain products. The authors experience in teaching a short course on phase-transfer catalysis has shown to us that a newcomer to PTC can easily be frustrated and confused by the large amount of information available in the literature and in patents. The purpose of this book, therefore, was to bring this information together in a logical and user-friendly way, without sacrificing matters of scholarly and fundamental importance."
Conventional synthetic materials, like metals, ceramics or glass, are usually isotropic substances, and their suitability for structural applications is achieved by morphological design and combination in the macroscopic scale. However, in modem engineering this is often not acceptable. As an alternative, the use of non-homogeneous, anisotropic materials, with significant stiffness and strength only in the directions these mechanical properties are really needed, can lead to enormous material (and weight) savings. This is the case of multiphase systems called composite materials. In these composites, different material parts are added and arranged geometrically, under clearly designed and controlled conditions. Usually, a structure of fibers provides strength and stiffness and a matrix helds them together, whilst providing the geometric form. Carbon fibers are among the high-performance fibers employed in these advanced structural composites, which are profoundly changing many of today's high technology industries. New research and development challenges in this area include upgrading the manufacturing process of fibers and composites, in order to improve characteristics and reduce costs, and modifying the interfacial properties between fibers and matrix, to guarantee better mechanical properties. The interdisciplinary nature of this "new frontier" is obvious, involving chemistry, materials science, chemical and mechanical engineering. Other topics, which more often are treated separately, are also important for the understanding of the processes of fiber production. Carbon filaments is one such topic, as the study of their mechanisms of nucleation and growth is clearly quite relevant to the production of vapour-grown carbon fibers.
Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions."
The immobilized biocatalyst (IMB) is a key component of biotransformation systems that are used to transform substrates to desired products. The impro- ment of biocatalyst properties has a direct influence on the overall effectiveness of the process based on the biotransformation. The basic catalytic characte- stics of biocatalyst that are followed include kinetic properties, pH optima, stability,and inhibition. The investigation of catalytic properties of immobilized enzymes is still a time consuming procedure and is not always simple. In the 1980s,a major effort was made to standardize the rules by which IMB is char- terized. The Working Party of EFB on immobilized biocatalysts has formul- ed principles of individual methods, among them the requirement of kinetic characterization [1]. It was recommended to use a packed-bed reactor,equipped with temperature control and with infinite flow circulation. The system should be equipped with a post-column unit to measure the time-dependence of the product or substrate concentration [2, 3], the most commonly used analytical methods being spectrophotometry, chemiluminiscence, automatic titration, bioluminiscence, chromatography, polarimetry, and biosensors based on the oxygen electrode. There are two main drawbacks to the application of these methods: 1. The need to vary the analytical principles, depending on the chemical and physical-chemical properties of analytes; 2. In some cases, mainly in the study of hydrolytic enzymes, the natural s- strate must be replaced by an artificial one,that is chromolytic,chromogenic, chemiluminiscent,bioluminiscent,or fluorescent.
PEO Unsaturated Macromonomers ................... 21 PEO Saturated Macromonomers ..................... 24 PEO Block and Graft Copolymers .................... 25 Dispersion Polymerization of PEO Macromonomers ......... 27 Copolymerization of PEO Macromonomers with Styrene ...... 27 Copolymerization of PEO Macromonomers with Alkyl Acrylates and Methacrylates .................... 33 Emulsion Polymerization of PEO Macromonomers ......... 34 Homopolymerization of PEO Macromonomers ............ 34 Copolymerization of PEO Macromonomers with Styrene ...... 39 Copolymerization of PEO Macromonomers with Other Comonomers ............................ 45 Polymerization of PEO Macromonomers in Other Disperse Systems .......................... 48 Conclusion ................................. 50 References ................................. 52 List of Abbreviations and Symbols A acrylic group second virial coefficient A2 AA acrylic acid AVA 4,4'-azobis(4-cyanovaleric acide) AIBN 2,2'-azobiisobutyronitrile B A butyl acrylate BzMA benzyl methacrylate BMA butyl methacrylate CAC critical association concentration concentration of monomer in water cw concentration of polymer micelle concentration CMC critical CFC critical flocculation concentration CFT critical flocculation temperature chain length (CL) Radical Polymerization of Polyoxyethylene Macromonomers in Disperse Systems 3 methyl Cl t-butyl tC4 chain transfer constant to stabilizer cs chain transfer to solvent css chain transfer constant for transfer to polymeric stabilizer CSP D particle diameter DLS dynamic light scattering volume median diameter D50 final particle diameter " f DBP dibenzoyl peroxide number average degree of polymerization DPn diffusion coefficient of the radical in water " w overall activation energy EO activation energy for propagation E activation energy for termination E t activation energy for decomposition of initiator Ed EO ethylene oxide unit f initiator efficiency monomer feed composition fw graft available G a graft required G r HLB hydrofile-lipophile balance
The flow of two-phase mixtures through restrictions. is a complex phenomenon that to date has not been fully described analytically. It is an area that received a geat deal of attention because of its application to nuclear reactor technology. The majority of the work done in this area considered ideal geometries such as nozzles, orifices and straight pipes. In the area of control valves very little work has been done. Brockett & King [1] studied subcooled water. Stiles [2] looked at subcooled freon. Martinec [4] compared subcooled freon in valves with ideal geometries. Sheldon & Schuder [3) looked experimentally at airjwater mixtures through valves that resulted in a sizing procedure. Fagerlund [10] presented an analytical model that required use of the Sheldon & Schuder data to establish the behavior of valves as opposed to more ideal geometries. However, the data used was limited to a single valve travel. Fagerlund & Storer [11] have expanded this to include several valve travels that further generalizes the technique. It is the intent of this paper to summarize a practical approach to s1z1ng valves for two-phase service that may be reduced to either a graphical or calculator procedure. Discussion of Analysis A fundamental assumption in this method is that the quality remains constant between the inlet and the vena contracta. For gas-liquid flows it is obvious providing vaporization does not occur.
The Industry-University Cooperative Chemistry Program (IUCCP) has sponsored eight previous international symposia covering a range of topics of interest to industrial and academic chemists. The ninth IUCCP Symposium, held March 18-21, 1991 at Texas A&M University was the second in a two part series focusing on Biotechnology. The title for this Symposium "Applications of Enzyme Biotechnology" was by design a rather all encompassing title, similar in some respects to the discipline. Biotechnology refers to the application of biochemistry for the development of a commercial product. Persons employed in or interested in biotechnology may be chemists, molecular biologists, biophysicists, or physicians. The breadth of biotech research projects requires close collaboration between scientists of a variety of backgrounds, prejudices, and interests. Biotechnology is a comparatively new discipline closely tied to new developments in the fields of chemistry, biochemistry, molecular biology and medicine. The primary function of Texas A&M University is to educate students who will be appropriately trained to carry out the mission of biotechnology. The IUCCP Symposium serves as an important forum for fostering closer ties between academia and industry and exchanging ideas so important to this evolving area. |
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