Pressure drop in pneumatic transport

An Empirid Approach for Calculating the Pressure Drop in Pneumatic Transport 1339... 

Ally, M.R. and G. E. Klinzing, Inter-relation of Electrostatic Charging and Pressure Drops in Pneumatic Transport," Powder Tech, (short Comm.) 44, 1985, pp. 85-88. 

Ally MR, Klinzing GE. Inter-relation of electrostatic charging and pressure drops in pneumatic transport. Powder Tech 44(l) 85-88, 1985. 

Smeltzer, E. E., Weaver, M. L., and Klinzing, G. E., Pressure drop losses due to electrostatic generation in pneumatic transport, Indust. Engrg. Chem, Proc. Des. Dev., 21 390-394 (1982)... 

For transport of a gas-solid suspension, it is important to be able to evaluate the pressure drop in order to estimate the power consumption. In a pneumatic conveying system, particles are usually fed into the carrying gas and accelerated by the gas flow. The power consumption (or pressure drop per unit pipe length) for the acceleration of particles can be significant compared with that for a fully developed flow condition. Moreover, the pressure... 

Bends complicate the design of pneumatic dilute phase transport systems and when designing a transport system it is best to use as few bends as possible. Bends increase the pressure drop in a line, and also are the points of most serious erosion and particle attrition. 

Schuchart P. Pressure drop aeross bend in pneumatic transport. Chem Eng Technol 41 1251, 1969. 

S. Laouar and Y. Molodtsof, Ejqjerimental characterization of the pressure drop in dense phase pneumatic transport at very low velocity. Powder Technology 95, pp. 165-173 (1998). 

Either a liquid or a gas can be used as the carrier fluid, depending on the size and properties of the particles, but there are important differences between hydraulic (liquid) and pneumatic (gas) transport. For example, in liquid (hydraulic) transport the fluid-particle and particle-particle interactions dominate over the particle-wall interactions, whereas in gas (pneumatic) transport the particle-particle and particle-wall interactions tend to dominate over the fluid-particle interactions. A typical practical approach, which gives reasonable results for a wide variety of flow conditions in both cases, is to determine the fluid only pressure drop and then apply a correction to account for the effect of the particles from the fluid-particle, particle-particle, and/or particle-wall interactions. A great number of publications have been devoted to this subject, and summaries of much of this work are given by Darby (1986), Govier and Aziz (1972), Klinzing et al. (1997), Molerus (1993), and Wasp et al. (1977). This approach will be addressed shortly. 

Yang, W. C., and Keaims, D. L., Estimating the Acceleration Pressure Drop and the Particle Acceleration Length in Vertical and Horizontal Pneumatic Transport Lines, Pneumotransport 3, pp. D7-89 (1976a)... 

Blasco et al. [12] proposed two-dimensional mathematical model for the drying process of dense phase pneumatic conveying. However, heat and mass transfer were not considered and therefore their model may be used for dense phase pneumatic transport only. In their paper, both experimental and numerical predictions for axial and radial profiles for gas and solid velocity, axial profiles for solid concentration and pressure drop were presented. 

Powder handling—gentle treatment reduces the level of free fat hence, avoid pneumatic transport, use a type of dryer with a low cyclone fraction, operate with a low pressure drop over cyclones, allow adequate powder cooling in fluid bed, and avoid high powder moisture from first drying stage. 

Particle-fluid flow has been in existence in industrial processes since the nineteenth century. Applications include pneumatic conveying, which deals with pipe flow of solid material transported by a gas, slurry transport and processing of solids in a fluid. The necessity of predicting blower or pumping power for a given amount of material to be conveyed led to measurements of pressure drops and attempts in the correlation of physical parameters. That anomaly exists in the correlation in terms of simple parameter is one of the motivations for the exploration into the details of distributions in density and velocity and the present state of development of instrumentation. 

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