Pulp line pressure drop?

[asolhu]

Hi everyone!

What calculations do you use for estimating pressure drop for kraft pulp pipes?

I can calculate the pressure drop for water line. Is there a correction factor etc available, which could handle the effect of consistency/ pulp type? I can live with a rough estimate.

Thanks for your time!

 

[JKEngineer]

Quite a bit has been published on this in the last 50 years. Do a literature search. Also look to TAPPI, CPPA, and the other technical organizations in the industry. I would be surprised if some of the texts on pulping don't also have some correlations or corrections.

I have seen what you are looking for, but not in the last 10 years or I would be more specific in my comments.

Jack

Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

http://www.KleinfeldTechnical.com

 

[drnyhus]

Unfortunately, there is no simple conversion factor since piping losses are affected by stock consistencies, temperatures, freeness, velocities, type of stock, whether it is virgin or repulped, etc, etc, and the behavior due to these factors is not a linear correlation with the behavior of water. If you have access, follow the recommendations of TAPPI TIS 0410-14 or as laid out in the technical section of most pump supplier manuals (I use Goulds Pump Manual GPM6 as a quick reference, but others are as good).

As a quick reference, 3.5% Northern Kraft at 190 deg F pumped at 4 ft/sec in a 10" stainless line has a straight pipe friction loss of approx 6 ft/ 100ft. Friction losses for fittings and valves are higher than with water as well (rule of thumb is a 20% increase for every 1% increase in consistency).

All bets are off over 5% consistency...you need to have advice when dealing with medium and high consistency kraft slurries.....it dewaters and turns to presto-logs if you don't know what you are doing.

Good luck,

Dwayne Nyhus,
Manager, Engineering
NorskeCanada Powell River Division