Mechanical processing technology

During most processes of mechanical process technology, the solid matter treated is divided into particles of different sizes and shapes. According to Figure 2 the size range covers six to eight orders of magnitude. 

The discrete elements are called particles their sizes range from large pieces with linear dimensions of several meters through millimeter-sized grains to submicrometer dust. Therefore, the descriptive term particle technology is often applied to large areas of mechanical process technology. 

Beginning in 1957 by H. Rumpf, Professor at and Director of the Institute of Mechanical Process Engineering at the Technical University (TH) of Karlsruhe, West Germany, and later by others, mechanical process technology was opened to scientific treatment by introducing definitions and classifications. 

Figure 3. Unit operations and related fields of mechanical process technology according to Rumpf ...

It must be stressed that, in the context of this book, the treatment of methods of particle size analysis, which are of great importance for all unit operations of mechanical process technology, must be simple and can not be complete. The task of these chapters will be to provide an overview, to discuss specific problems and limitations of certain methods, and to point out suitable procedures for application in size enlargement. For more detailed information the extensive literature covering this field should be consulted. 

Fig. 1.1 Unit operations and associated techniques of Mechanical Process Technology...

Tab. 5.11 lists the operations of Mechanical Process Technologies (see Chapter 1, Fig. 1.1) and indicates if agglomeration is desired or undesired or, sometimes, both. 

While in the newer fields of industrial technologies, for example chemistry, electronics, communications, etc., process research and plant development started from first principles and many of the equipment and system designs had to be newly elaborated for a particular purpose using modem thought processes as well as manufacturing and industrial methods, even the new Mechanical Process Technologies mostly still rely on fundamentals that are rooted in the purely empirical past enhanced by the know-how of expert persons and/or companies. 

B.15 H. Schubert et al., Mechanische Verfahrenstechnik (Mechanical Process Technology), Deutscher Verlag fur Grundstoffindustrie, Leipzig, DR Germany (1977). 

K. Schonert, Mechanische Verfahrenstechnik - Insbesondere Umgang mit feinen Parti-keln (Mechanical Process Technology - Particularly processing of fine particles), Friderici-ana, Z. der Univ. Karlsruhe, Verlag C.F. MuUer, Karlsruhe, FR Germany (1977)21, 12-33. 

Like many original methods of mechanical process technology, an old technique for the successful removal of airborne dust was first observed in nature. The capacity of rain to clear the air has been used since ancient times to remove suspended dust particles by passing the contaminated gas through a water spray (wet scrubbers). The liquid droplets capture the solid (and some of the gaseous) pollutants and collect them in a sump. While this reduces air pollution it transfers part of the separation problem to a secondary cleaning process the removal of fine particulate solids from a liquid. 

In conclusion, test equipment is available in all areas of interest for the determination of feed and product characteristics, including new techniques that have been developed in response to advancements in modem mechanical process technology and to new applications for the manufacturing of novel, for example, engineered products. However, testing is only as good and predicts industrial performance of the projected plants as correctly as test conditions reflect what will be found later in the actual installation. 

In the process industry, a HAZOP study is most commonly applied to process line diagrams. A standard P ID (Process and Instrumentation Diagram) is a description of the future intent, typically the steady state of a continuous process. Batch systems can also be studied but in those cases a description of the batch process steps is required in addition to the P ID. In systems of mechanical process technology (powder and bulk solids), at various points, the characteristics of the solids and, if applicable, their interactions with each other and with process fluids and their possible deviations must be included in the study. 

In contrast to chemical processes, where the feed materials and process aids (catalysts) are in most cases well defined, clean, and consistent, the particulate solids in mechanical process technologies, especially if they are or were derived from naturally occurring raw materials (minerals, concentrates), may vary widely in composition and/ or physical characteristics. As mentioned before (Chapter 3), when agglomeration processes are involved, the surface properties of the particles (macroscopic and microscopic shape, roughness, contamination by adsorption and absorption) are of particular importance and modifications that are sometimes difficult to detect, may require a new set of operating parameters or the introduction of for example, binders, surfactants, or other additives. 

For installations of mechanical process technology, whether new or adapted to different process conditions, feed materials, and/or products, these limiting preconditions on design, selection, execution, and initial operational availability should be avoided. Particularly if agglomeration processes are involved (above. Chapter 3,... 

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