How to size soild particle pipe line velocity

[koba78]

Dear Eng-tips members:

Anyone can kindly help me any easy program, excel or... to

determine the velocity of the solid phase in pneumatic

transport?

It seems this solid phase transport in a stagnated dense phase
or dilute phase in pipelines is very complex configuration
or totally different from each other.

In dilute phase,if we increase the velocity,the pressure drop will go up. Conversely,if we crank up velocity,we may need more pressure to do this.

But, in dense phase, if we want to increase the velocity,and we may need to decrease the pressure drop. Or the distribution of solid in the pipe have to get first so that we can size the pressure drop of the pipe.(Ex.uniformly distrusted change to half distribute, pressure drop behavior may be different)

So, the pressure drop for the dilute phase solid seems could be sized just as sizing the pressure drop for the liquid phase, but dense phase solid couldn't mean the same thing.

Is my comprehension for this subject is correct or any other pro
can help me out?


Thank you very much for your generous help.

 

[koba78]

First approximation of the solid vessel pressure (dilute phase)

delta P_dp = W_dp/A_dp * g/g_c (psi)
where delta P_dp = the dilute phase pressure differential (psi)
W_dp= the dilute phase holdup(lb)
A_dp = the vessel cross sectional area in the dilute phase region (in^2)
g = the acceleration due to gravity (32 ft/S^2)
g_c= the gravitional conversion factor (32 ft lb mass/ S^2 lb force)

 

[cheute79]

Aside from calculating velocities, also consider the impacts (a pun) of pneumatic transport methods. Dilute phase will tend to pulverize the solids more than dense phase, dense phase can blind if the solids are even the least bit sticky, dilute phase will induce a lot more erosion in the pipe (especially elbows), and other considerations. Being aware of or considering such might help you drop one as an option, and help you make quicker work of the design.