Re: Sunflower Shells Pneumatic Conveying
Dear Tanase,
I quickly recalculated your project and found that the design would work well.
From the presented data I was not able to account for all the possible pressure drops, which could explain that I calculate a somewhat lower conveying pressure.
The suspension velocity of the sunflower shells is not yet assessed properly, but due to the low SLR of no significant importance.
The Rotary Valve seems a bit too small. ■
Teus
Sunflower Shells Pneumatic Conveying
Dear Mr. Teus,
Thank you very much for your attention and advices.
I'm sure the pressure loss calculated by you is the right one, since i rounded-it up at 230 mbar, adding some safety margin.
More, the system is configured as following:
- for 6 to/h there is one valve
- for 12 to/h there are 2 pcs. of valves arranged in line, with single larger loading hopper
Capacity:
1. for the line of 7,0 to/h:
- the valve diam. i was considered is having a diam. of 450 mm
- following your advice i reconsidered the valves and provided valves with diam. of 500 mm
- the 500 mm diam. valves has a specific volumetric capacity of 95 liters/rev., which for 20 rev/min gives a theoretical volume capacity 114,0 m3/h
- for a filling degree of about 60 % and product bulk density of 110 kg/m3, gives a capacity of 7,5 to/h (required 7,0 to/h)
2. for the line of 12,0 to/h:
- details of single valves as here above
- for 16 rev/min, it gives a capacity of 91 m3/h x 2 = 182 m3/h
- for the same loading degree and same bulk density gives a capacity of 12,01 to/h (required 12,0 to/h and there is still some margin, if necessary, for to increase the speed to 18 rev/min)
3. Pipe diam. and line configuration:
- for the system of 7,0 to/h it is the specified one of 141 mm inside diameter
- for the system of 12,0 to/h the pipe is 229 mm inside diameter
- line configuration: each one as described previously (slightly differences in the horizontal straight length)
One more time, thank you for sharing with us your valuable experience for free.
Sincerely yours,
Tanase TANASE ■
Re: Sunflower Shells Pneumatic Conveying
Sunflower shells are surprisingly abrasive. Rotary valve and bends will wear fast.
Keep this in mind.
Don't forget to add RV air leakage to airflow since it is big one. ■
Sunflower Shells Conveying Air Leakage
Dear Dr. Mantoo,
Thank you very much for your valuable comment.
Yes, i know, the abrasiveness of the sunflower shells is really a pain in the back for the factory maintenance.
They are using a kind of reinforced bends with high abrasion resistance material.
Air leakage on RV: yes, thank you for the mention. Given the diameter of the valve the total length of the slot is a large one.
But having a compression ratio lower than 1,4:1 it is somehow very diminished.
Wish you all a pleasant week-end.
Sincerely yours,
Tanase TANASE ■
Sunflower shells pneumatic conveying
Dear All,
Hope you are doing well and you are safe of this corona.
I have an issue and hope you can help me with your valuable advices.
I have to design a pneumatic conveying system for sunflower shells. The capacity is quite high, about 6,0 to/h for this product having a bulk density of about 110-120 kg/cubicmeter.
The total length of the line is about 60 m, of which 20 vertical and 40 horizontal. There are about 5 bends at 90 deg. each.
I will design it as a dilute phase conveying system, using a blower compressor and drop-through valve.
My questions to you will be about:
1. drop-through valve:
- i considered it drop-through and not blow-through, since this product comes in forms of chips and sound more appropriate to me to use drop-through
- valve speed: this product has a very low floating speed and therefore for a good loading of the compartments of the valve, i considered a 16 rev/min as speed of the valve
- valve diam.: this should be correlated with the speed and therefore i have chosen a 450 mm diam. valve, with a specific volume capacity of about 60 liters/rev.
- i considered a filling degree of about 60 %
- the question here is: should i use an off-center valve or standard one ? i'm afraid about the possible stuck of the rotor due to the shell getting into the gap between the rotor and body. What is your experience and opinion ?
2. Pipe diam.: the pipe i provided is 141 mm inside diam. Mixing ratio of about 3,5 and 24 m/s as air flow end speed.
3. System resistance:
- i estimated a pressure loss of about 230 mbar.
- i do not have any clue about the clogging condition (clogging constant)
- i do not have any clue about the saltation velocity. The shape of this chip is very asymmetrical.
- having this lower sistem resistance, i decided to make straight pipe, single diameter and not stepped (low compression degree as for 19,52 m/s in the feeding zone).
Your advice or experience will be highly appreciated. Especially about the type and solution for the valve.
Thank you for your support.
Sincerely yours,
Tanase TANASE ■