Transport pellets

The automated pellet hardness tester is computer controlled and transports pellets to a measuring gage. The result is given as the force required to crush a pellet of a measured diameter. ... 

Table 4 shows, the sources are available with physical sizes ranging from 1 mm x 1 mm up to 3 mm x 3 mm. They are produced from firmly compressed selenium pellets of cylindrical shape. The activities range up to 3 TBq or 80 Ci, which is the maximum allowed loading of the GammaMat SE portable isotope transport and working container, as well as the Source Projector M-Se crawler camera. 

The final chapters, 11 and 12, are concerned with the particular application of transport theory to which this monograph is principally directed, namely the modeling of porous catalyst pellets. The behavior of a porous catalyst is described by differencial equations obtained from material and... 

Particle Size Reduction. Changes in the physical characteristics of a biomass feedstock often are requited before it can be used as a fuel. Particle size reduction (qv) is performed to prepare the material for direct fuel use, for fabrication into fuel pellets, or for a conversion process. Particle size of the biomass also is reduced to reduce its storage volume, to transport the material as a slurry or pneumatically, or to faciHtate separation of the components. 

Applications have largeU been for plastics in powder and pellet forms. By modifications, needed coohng operations have been simultaneously effected with transport to stock storage [Plost. Des. Process., 28 (December 1968)]. 

Alfalfa dehydration is carried out in a direct-fired rotary dryer. The dried product is transported pneumatically to an air cooler and then to a collecting cyclone. The collected particles are ground or pelletized and then packaged for shipment. The major atmospheric emission from the process is particulate matter, which is controlled by baghouses. Odors may also be a problem, but they disperse rapidly and are no longer a problem at distances of over 1 km. 

Table 4-4 summarizes the ratings of the various reactors. The CFSTR and the recirculating transport reactor are the best choices because they are satisfactory in every category except for construction. The stirred batch and contained solid reactors are satisfactory if the catalyst under study does not decay. If the system is not limited by internal diffusion in the catalyst pellet, larger pellets could be used and the stirred-contained solids reactor is the better choice. However,... 

In the Cape Basin region of the South Atlantic, polyethylene and polypropylene pellets were observed at concentrations of 1333-3600 pellets km (48). Since this area is far from any major shipping lane and is dominated oceanographically by the Antarctic West-Wind Drift with possibly some input from the Brazil Current, the source of the floating plastic was thought to be ships transporting the raw material in the South Atlantic (48). The weathered appearance of the pellets indicated that they had been adrift for an extended period and, therefore, carried long distances by the ocean currents. 

Polyethylene pellets were Very abundant" on the Mediterranean coast of Spain, particularly near plastics fabrication factories (39, 40). Wastes from these factories and spillage during cargo loading and transport of raw materials were considered to be the major sources. Similarly, wastes from local plastic fabrication factories were thought to be the source of pellets on the beaches of Lebanon (40). 

Whitaker, S, Transport Processes with Heterogeneous Reaction. In Concepts and Design of Chemical Reactors Whitaker, S Cassano, AE, eds. Gordon and Breach Newark, NJ 1986 1. Whitaker, S, Mass Transport and Reaction in Catalyst Pellets, Transport in Porous Media 2, 269, 1987. 

While the previously described techniques were measuring the nanoscopic and microscopic properties of the catalyst pellets, respectively, fluid transport within... 

As the screw turns, it conveys the pellets from the feed zone towards the melting zone. A combination of external heating and mechanical work melts the polymer as it is transported towards the metering zone. The metering zone pumps a uniform stream of molten polymer to a forming device, such as a profile die. Other types of extruders that employ two or more screws are commonly used for compounding polymer blends. The principles of twin screw extrusion will be discussed in Chapter 12. 

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