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?

Thanks.

Sundar Narayan ■