Pneumatic transport, of solids

Although the phenomena are not clearcut, partial settling out of solids from the gas stream and other instabilities may develop below certain linear velocities of the gas called choking velocities. Normal pneumatic transport of solids accordingly is conducted above such a calculated rate by a factor of 2 or more because the best correlations are not more accurate. Above choking velocities the process is called dilute phase transport and, below, dense phase transport. 

For pneumatic transport of solids in a dilute suspension, the effects of apparent mass, Basset force, diffusion, and electric charge of the particles may be ignored. Thus, the dynamic equation of a small particle in a gas medium is given by... 

Conference on the Pneumatic Transport of Solids in Pipes (Pneumotransport 3), Bath, England. E5 - 49. 

Colver, G. M. and A. M. Sarhan, Pneumatic Transport of Solids with Electric Field, Second Internl. Particle Tech. Forum, 5th World Congress of Chemical Engineering, Vol. VI, AIChE, San Diego, CA., July 14-18, 1996, pp. 436-442. Colver, G. M. and D. L. Howell, Particle Diffusion in an Electric Suspension, Conference Record, IEEE Industry Applications Society Annual Meeting, Sept. 28-Oct. 3, 1980, pp. 1056-1062. 

Pneumatic transportation of solids is important to many industrial processes, for example transporting coal and powder particles. To an operator of such a pneumatic conveyor, the mass flow rate of the solids is the primary process parameter to be measured accurately. A solid/gas flow is very difficult to control because it behaves quite differently from solid/liquid flows. A recent review (Yan, 1996) discussed several variables that may affect the performance of a flow instrument. The distribution of solids in a pneumatic pipeline can be highly inhomogeneous consequently, the particle velocity distribution over the pipe cross section can be widespread. Figure 6.28 shows examples in which the roping type flow is particularly difficult to understand and monitor. 

Molerus O., Overview - pneumatic transport of solids. Powder Technology, 88,309—321, 1996. 

In the entrained-flow reactor (Figure 18.11), the solid particles travel with the reacting fluid through the reactor. Such a reactor has also been described as a dilute or lean-phase fluidized bed with pneumatic transport of solids. 

Klinzing GE, Rohatgi ND, Myler CA, Dhodapkar SV, Zaltash A. Pneumatic transport of solids in an inclined pipe. Can J Chem Engr 67 237-244, 1989. 

K. Konrad, D. Harrison, R.M. Nedderman and J.F. Davidson, Prediction of the pressure drop for horizontal dense phase pneumatic conveying of particles, Proc. 5th Int. Conf. on Pneumatic Transport of Solids in Pipes, Pneumotransport 5, pp.225-244 (1980). 

The pneumatic transportation of bulk solids through pipelines has been in existence for over one hundred years. Some of the earlier applications included the vacuum unloading of grain from ships and the extraction of sawdust from timber mills. 

Pipelines to transport solids are called freight pipelines, of which three different types exist pneumatic pipelines, the use of which is known as pneumotransport or pneumatic conveying slurry pipelines, which may also be called hydrotransport or hydraulic conveying and capsule pipelines. When air or inert gas is used to move the solids in the pipeline, the system is called a pneumatic pipeline and often involves a wheeled vehicle inside the pipeline, propelled by air moving through the pipe (25). Slurry pipelines involve the transport of solid particles suspended in water or another inert liquid. Hydraulic capsule pipelines transport solid material within cylindrical containers, using water flow through the pipeline for propulsion. 

The adhesion of colloidal particles to solid substrates is of fundamental and technological importance (e.g. pneumatic transport of powders, printing, filtration, detergency, air pollution). In general,... 

The spouted beds (SBs) can also be used to dry polymer beads. It is an efficient solid-gas contactor. In the conventional SB there is dilute-phase pneumatic transport of particles entrained by the spouting jet in the central core region and dense-phase downward motion of the particles along the... 

In horizontal pneumatic transport of particulate solids, what is meant by the term saltation velocity ... 

Matsumoto S, Kikuta M, Maeda S. Effect of particle size on the minimum transport velocity for horizontal pneumatic conveying of solids. J Chem Eng Japan 10, No. 2 273, 1977. 

Bulk handling of solids is usually accomplished by use of bins and conveyors. But solids may also be transported by suspension in a liquid or a gas. The latter method of transport is the subject of this book. Often, the suspension of solids in a liquid is not desirable from a process standpoint. The solids may dissolve or change character in the liquid, or the presence of the liquid may not be desirable in some high-temperature process. In these cases, one must resort to gas-solid transport or pneumatic transport of the solids for movement. 

P.W. Wypych and A.R. Reed, The advantages of stepping pipelines for the pneumatic transport of bulk solids. Powder Handling Processing, 2 (19W) 217-221. 

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