Dear JP,

Missing information is:

polypropylene pellets:

- particle size (distribution)

- particle density

- bulk density.

Are you considering a vacuum system or a pressure system?

Best regards

Teus ■

Hi there! Try the following link

https://forum.bulk-online.com/showth...-Installations

In the second list of this thread you will find the data of two industrial installations published on Bulk-online.

Regards

Manfred Heyde ■

Dear JP,

Attached a preliminary pneumatic conveying calculation for the PP pellets.

Pay attention to the rotary valve.

take care

Teus

Attachments

pppellets (PDF)

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My calculations show that a 4 inch diameter line will be adequate for conveying 10 tons/hr. Pressure drop comes to 3.8 psi and air flow comes to 1465 lbs/hr.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com ■

Dear Amrit, JP,

I recalculated the installation for a 4” pipeline, using

3.8 psi equals approx. 2700 mmWC

Airflow 1465 lbs/hr equals approx. 666 kg/hr # 555 m3/hr # 0.154 m3/sec

Find the calculation results in the attachment.

The calculation indicates a saltation problem.

Have a nice day

Teus

Attachments

calculation-4-inch (PDF)

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My calculations are based on using a pick up velocity of 65 ft/sec. This velocity keeps on increasing along the conveying line. My experience shows that pick up velocity of 65 ft/sec is sufficient for PP pellets.

I will be glad to run my calculations again if some one has a better number for PP pellets saltation velocity.

Regards,

Amrit Agarwal

Pneumatic Conveying Consulting ■

For PP pellets saltation is not an issue as chocking doesn't occurs easily, might occur very long systems. One should differentiate between fine powders and pellets when it comes to pneumatic conveying. 19 m/sec pick is very high for pp pellets will get a lot of angel hairs. Industry standard for these pellets will be a low pressure dense phase based on a standard rotary valve and roots blower running at probably quarter of the stated pick up velocity. ■

Angel hair/streamers are not a big enough concern for PP pellets as to justify a dense phase conveying system. Dilute phase systems with a cyclone at the end are satisfactory.

Regards,

Amrit Agarwal ■

Dear JP,

From your chosen data:

Material mass flow = 6000 kg/hr

SLR =5

Resulting in: Air mass flow = 6000 / 5 = 1200 kg/hr

Equals approx. 1200/1.2 = 1000 m3/hr (#16.6 m3/min # 0.277 m3/sec)

(You mention 787.48 m3/hr)

Note:

The e-motor power driving the GM10S allows for approx. 0.16 m3/sec at 0.5 barg (# 9.6 m3/min #576 m3/hr)

You have not mentioned the predicted conveying pressure.

Pipe diameter 78 mm

Velocity = 16.5 m3/sec

Airflow = 3.14/4 * 0.078 * 0.078 * 16.5 = 0.079 m3/sec (atmospheric)

In case this velocity is at the pick-up point at 0.5 barg (1.5 bara), then:

Air flow = 0.079 * 1.5 = 0.118 m3/sec. (0.1421 kg air/sec # 511.8 kg/hr)

At 6 tons/hr, this results in a SLR = 6000 / 511.8 = 11.8 (Not 5)

Conclusion:

The figures do not add up.

Have a nice day

Teus ■

Hello ,

Concerns about angel hair and skinning over ride any other design consideration .

Pipe should be rough inside , rifled or equivalent , will prevent . Sounds strange , but does work !

Line velocity management is another important consideration .

You may want to consider dense phase , BUT the particle size distribution is critical to success .

Pneumatic Conveying Consultants -- Paul Solt has a lot of experience .

Your suppler should be helping as well

Originally Posted by JP (Mechatronics)

Good day to everyone,

I was given a project to design a dilute phase pneumatic conveying system for polypropylene pellets.

I am still very much a novice at pneumatic conveying, so therefore as I get to each new section of the design, I research the system/component I will be needing. Time has however now become a concern and I am in need of some help. The system should be able to load anything from 6 to 10 tons per hour to the silo.

The components I have available are as follows:

An Aerzen GM 10 S blower with the following specifications which can be read off the corroded plates:

Pump:

- Shaft power: 12.9kW

- Speed: 4800rpm

- Q: 10.9m^3/min

- Differential P: 500mbar

Siemens Motor:

- 15kW, 29,9A

- 400V Delta

A 8-vane rotary feeder:

- Pocket volume: 0.0007541624 m^3

Motor:

- 1.37kW

- 1400rpm

- Gear ratio, 1:2

A S/S silo with 14m^3 volume capacity.

With these items I have to now be able to convey the material over a horizontal distance of 5.5m as well as a vertical distance of 5.5m. It should contain two 90 degree bends between the blower and the rotary feeder. It should also contain a 45 degree long radius bend and two 90 degree long radius bends between the rotary feeder and the silo.

My biggest concern however is the pipe diameter to use, as I need to get this order placed as soon as possible. From some rough calculations and estimates I have reckoned 100mm diameter would be sufficient, although my seniors tends to disagree. I want to figure out which pipe diameter, what conveying velocity and which solids loading ratio would best fit. I want to be able to justify it too, for my personal understanding and learning curve.

I am allowed to alternate the gear ratios on both the blower and rotary feeder, if this would help better the system.

Any help would be much appreciated. Hope the information I provided would be efficient.

Regards

JP

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Originally Posted by SCJohn

Hello ,

Concerns about angel hair and skinning over ride any other design consideration .

Pipe should be rough inside , rifled or equivalent , will prevent . Sounds strange , but does work !

Line velocity management is another important consideration .

You may want to consider dense phase , BUT the particle size distribution is critical to success .

Pneumatic Conveying Consultants -- Paul Solt has a lot of experience .

Your suppler should be helping as well

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Dense phase for PP pellets is not required. Angel hair is not a problem at all with dilute phase conveying of PP pellets. A simple cylone at the end of the conveying line is enough to remove any dust that is created. There is no need to use rifled pipe lines. This is based on my more than 30 years of designing and running PP conveying systems.

Regards,

Amrit Agarwal

Consulting Engineer

Pneuamtic Conveying Consulting ■

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Originally Posted by SCJohn

Hello ,

Concerns about angel hair and skinning over ride any other design consideration .

Pipe should be rough inside , rifled or equivalent , will prevent . Sounds strange , but does work !

Line velocity management is another important consideration .

You may want to consider dense phase , BUT the particle size distribution is critical to success .

Pneumatic Conveying Consultants -- Paul Solt has a lot of experience .

Your suppler should be helping as well

■