Conveying of Moist powders & water droplets

(not verified)
Posted in: , on 15. Dec. 2002 - 21:53

Glad I discovered this forum. We build a grinder that also dries, without any heat input. From the grinding chamber, the powder is conveyed to a cyclone through a 3 meter long inclined and curved 0.4 m diameter duct. We pulverize and dry wood chips (hog fuel) among other things. The moisture content may reduce from 20 % wb to 10 % wb while being ground. (wb stands for wet basis).

What formula would I use to estimate the carrying velocity needed? I have seen a few formulas but they all require the density of a PARTICLE of wood.

1. How would I measure that density? Are there any formulas that use bulk density instead? Or is there a way to relate bulk density to the density of a particle?

2. How will the carrying velocity change as a function of the moisture content of the wood powder?


Sundar Narayan

Mark Kilfoil
(not verified)

Re: Conveying Of Moist Powders & Water Droplets

Posted on 18. Dec. 2002 - 06:24


1. Surely the density of a wood particle equals the density of solid wood, at the correct moisture content ?

2. The influence of moisture content is through its effect on particle density.

Hope this helps.


Mark Kilfoil

Mechancial Engineering

Technikon Witwatersrand

Phone + 27 11 406 2300

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