Chemical Engineering Unit Operations Research Articles

An analytical method for design of electrodialysis stacks operated at high concentrations

An analytical method analogous to the Kremser-like procedure used in chemical engineering unit operations has been developed for the design and performance evaluation of co-current and counter-current electrodialysis stacks operated at high concentrations. Membrane area or concentrations and flow rates of the outlet streams can be explicitly calculated. When the method is compared with numerical procedures, no relevant discrepancies are found between the two. For its simplicity it is very useful to process engineers for quick initial estimates and plant arrangements.

A graphical method for the design of an electrodialysis stack

A graphical method, analogous to the stairlike construction used in chemical engineering unit operations, has been developed for the design and performance evaluation of co-current and counter-current electrodialysis stacks. Membrane area or concentrations of the outlet streams can be explicitly calculated in the case of low solution concentrations. When the method is compared with numerical procedures, no relevant discrepancies are found between the two. For its simplicity it is very useful to process engineers for quick initial estimates and plant arrangements.

Grenzflächenprobleme bei der Fest/Flüssig‐Trennung

AbstractInterfacial problems in solid/liquid separation. Mechanical solid/liquid separation is one of the unit operations of chemical engineering, which is far from having been mastered theoretically. This is because interfacial forces play such a pronounced role in this process step, and these forces have so far largely withstood scientific investigation. The present article enumerates the problems involved, and necessarily presents more open questions than ready answers.

Behavior of Loose Fibrous Beds During Centrifuging

A new physical model is used to explain the mechanism of moisture retention in centrifuged textile fibers and is tested experimentally. The model enables computer predictions to be made of the regain of centrifuged beds in terms of the centrifuging conditions and the physical properties of the fluid and the fibers. The model treats the retained surface moisture as large agglomerates of fluid which occupy stable sites at points of contact between the individual fibers in a compressible bed. The computer solutions adequately predict the effects of the process variables as observed by other workers and explain some of their apparently conflicting results. The proposed theory has been tested successfully using both non-hygroscopic (polyester) and hygroscopic (wool) fibers. This treatment advances the aim of making centrifuging a fully pre dictable chemical engineering unit operation.

Unit operations used to treat process and/or waste streams at nuclear power plants

An attempt is made to identify the main sources of low-level radioactive wastes (LLW) that are generated at light water reactor (LWR) nuclear power plants in the United States. To place the LWR waste problem in perspective, rough estimates are given of the annual amounts of each generic type of LLW [i.e., government and commercial (fuel cycle and nonfuel cycle)] that is generated. Most of the wet solid wastes arise from the cleanup of gaseous and liquid radioactive streams prior to discharge or recycle. Many different chemical engineering unit operations have been, are being, and likely will be used to treat process and/or waste streams at LWR plants. These include adsorption, evaporation, calcination, centrifugation, compaction, crystallization, drying, filtration, incineration, reverse osmosis, and solidification of waste residues. The treatment of these various streams and the secondary wet solid wastes thus generated (e.g., filter cartridges, filter sludges, and spent ion-exchange resins) is described. The dry wastes from all LWRs have similar physical and chemical characteristics in that they can be classified as compactible, noncompactible, combustible, noncombustible, or combinations thereof. The various treatment options for concentrates or solid wet wastes, and for dry wastes are discussed. Among the dry waste treatment methods are compaction, baling, and incineration, as well as chopping, cutting, and shredding. Organic materials [liquids (e.g., oils or solvents) and/ or solids] could be incinerated in most cases. The filter sludges, spent resins, and concentrated liquids (e.g., evaporator concentrates) are usually solidified in cement, or urea-formaldehyde or unsaturated polyester resins prior to burial. Incinerator ashes can also be incorporated in these binding agents. Asphalt has not yet been used as a solidification agent in the United States, but it probably will be used in the near future. This paper presents a brief survey of operational experience at LWRs with various unit operations, including a short discussion of problems and some observations on recent trends. Such information is a valuable aid in retrofitting old equipment and in selecting new equipment. Some areas appearing to need more research, development, and demonstration are specifically pointed out.

Unit operations of chemical engineering, 3rd edition, W. L. McCabe and J. C. Smith, McGraw‐Hill, New York (1976). 1028 pages. $22.50

Unit operations of chemical engineering, 3rd edition, W. L. McCabe and J. C. Smith, McGraw‐Hill, New York (1976). 1028 pages. $22.50

The Current State and Future Directions of Industrial Plasma Chemistry

Some current activities in industrial scale plasma chemistry are discussed in terms of their present scale of operation, the rationale behind the use of a plasma step, and the prospects for their ultimate success. Trends in industrial energy consumption are described which are expected to accelerate the development of industrial plasma chemistry. Thermodynamic considerations in the use of diatomic gases are shown to recommend them as working fluids for plasma heating operations. Cooperation between Thermodynamicists, Heat Transfer Theoreticians, and Equipment Designers is recommended for the advancement of basic understanding as well as commercial viability of this new Chemical Engineering Unit Operation.

Thirteenth Annual Review of Unit Operations in Chemical Engineering

Thirteenth Annual Review of Unit Operations in Chemical Engineering

Unit operations of chemical engineering. Warren L. McCabe and Julian C. Smith. McGraw‐Hill Book Company, Inc., New Yark (1956). 945 pages. $10.50

AIChE JournalVolume 3, Issue 1 p. 9M-10M Book Unit operations of chemical engineering. Warren L. McCabe and Julian C. Smith. McGraw-Hill Book Company, Inc., New Yark (1956). 945 pages. $10.50 John A. Tallmadge, John A. TallmadgeSearch for more papers by this author John A. Tallmadge, John A. TallmadgeSearch for more papers by this author First published: March 1957 https://doi.org/10.1002/aic.690030126Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume3, Issue1March 1957Pages 9M-10M RelatedInformation

Unit operations of chemical engineering (McCabe, W.L., and Smith, J.L.)

Unit operations of chemical engineering (McCabe, W.L., and Smith, J.L.)

Design of Unit Operations Laboratories

DURING the summer of 1947, the author and R. K. Toner, both of Princeton University, were sent by that school on a tour of representative institutions teaching chemical engineering in order to study the construction of unit operations laboratories. The objective of the study was to lay the groundwork for an expansion of the undergraduate laboratory facilities at Princeton. Previous reports have been devoted to the construction and design of research laboratories ( 1 ), to the design of buildings for general instruction in chemical engineering ( 2 ), and to descriptions of new buildings and facilities at individual institutions ( 3, 4, 5 ). This study is restricted, however, to the particular problem of facilities for undergraduate laboratory instruction in the unit operations of chemical engineering. In the course of the examination of the existing and proposed laboratories at more than 25 institutions in eastern, central, and western United States and Canada, sufficient information of general interest wa...