Nonfluidized diplegs

The vertical moving bed has been used in many chemical processes as a nonfluidized standpipe or dipleg. The main function of the nonfluidized 

A Generalized Theory for the Dynamics of Nonfluidized Gas-Particle Flow 

Investigation of nonfluidized gas-particle flow began in the 1950s, although relatively little has been published on its flow patterns, dynamics, pressure 

The basic character of non-fluidized gas-particle flow is the existence of contact pressure (or stress) among particles and between particles and the pipe wall. Both theoretical analyses and experimental results (Terzaghi, 1954 Johanson and Jenike, 1972 Li and Kwauk, 1989) showed that the pressure of the interstitial fluid in particulate material neither compresses nor increases the shear resistance of the particulate material. After Walker (1966) and Walters (1973), Li and Kwauk (1989) analyzed the stresses in a vertical pneumatic moving-bed transport tube by using the stress theory of particulate media mechanics and Mohr circles, shown in Figs. 19 and 20, and gave the following stress ratios at any point in the flow field  

In the preceding equations, xh is the average axial normal stress over radial cross-section determined by the following equation  

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