Dear Neval,

I understand your thread as a possible replacement of a mechanical transport installation (auger, elevator) by a pneumatic conveying installation.

That means that a pneumatic conveying installation has to be designed and then the cost to be estimated.

To design and calculate a pneumatic conveying installation, at least the following data and parameters have to be known:

-pipeline routing (horizontal length, vertical length and nr of bends)

-pipe diameter (already set to 100 mm # 4”)

-Particle size (of each material)

-Particle density (of each material)

-Bulk density (of each material)

-Pneumatic conveying capacity (15 tons/hr)

-Method of feeding (Rotary valve with VFD e-motor drive)

From the particle size and particle density, the suspension velocity is determined

From the suspension velocity, the required air velocity is determined.

With the pipe diameter and the required air velocity, the required air volume displacement is calculated.

After that, in combination with the required capacity, the necessary pressure drop is calculated and the type of compressor can be chosen.

(The calculated pressure drop influences the leakage through the rotary valve and might require a second calculation iteration for a bigger or smaller compressor)

Subsequently, the filter size (m2) and filter fan (m3/min) on top of the silos can be determined.

In relation to the material properties (f.i. hygroscopic), the necessity of air treatment (drying) is established.

The pneumatic installation should be designed for the maximum capacity of the worst material. All the other materials will then be conveyed properly.

I assume that the mentioned materials can be supplied by bulk tankers (use 4” outlet), which can fill the silos directly. (No further equipment is needed)

If the materials are supplied in big bags, then use a bag emptying unit.

See: http://www.telschig.com/bigbag.html

If you can supply the above mentioned required input parameters, a indicative calculation can be made.

Have a nice day

Teus ■

Originally Posted by Neval

We have no experience with blowers. We have to fill silos with materials with different bulk density. We need assistance in choice of a relevant blower.

We do reconstruction in the company for the production of detergents. There are four silos, two unloading sites / hopper, auger and elevator /. Should be built pneumatic transport to silos of 4 products / sodium carbonate fine powder - bulk density 0.6, 1.5 sodium sulfate, sodium tripolyphosphate - 0.7 and zeolite - 0.5. On the screw, filling the elevator we put slide gate and blow- rotary valve with variable speed.

The height of the silo is 14 meters, the available vertical pipe DN 100. How to accommodate proper/suitable blower / m3/hr / to be able to fill silos 10-12-15 tons per hour with each of these materials separately.

Do I need to change the blower mode of work / m3/hr / depending on the material?

Thanks

Neval

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

Hello Neval,

Please start at the beginning:

Is this detergent manufacturing plant served by rail or

truck for ingredients?

A bucket elevator with four legs is easier to mantain as the piping is not subject to

pressure changes and excess wear from fast moving ingredients as they are traveling by gravity

after they leave the dumping spout. The bucket elevator is also much less likely to plug.

Why do they want to eleiminate the bucket elevator?

If by truck are the trucking companies using pneumatic

tankers or dump trucks with tarpaulins covering the loads?

If pneumatic tankers are used they typically have a positive displacement blower to create

pressure gradients to move material out of the pneumatic tank trailer into the silo.

NOW with that said:

You need to know what size piping that you need as well as the grade of steel and whether it has to be stainless which is what you may need for the dry ingredients. This has to/must be be determined before you size the positive displacement rotary lobe blower(s).

Sizing the blower is the easy part Nevel, so no worries there. you have to determine the pipe inside diameter then the steel type then you can determine the lengths of pipe needed as well. ■

Dear Neval,

The material data are:

Sodium Carbonate:

Na2CO3

Material density = 2540 kg/m3

Bulk density = 600 kg/m3

Average particle size = 253 micron

Resulting suspension velocity = 3.64 m/sec

Sodium Sulfate:

Na2SO4

Material density = 2664 kg/m3

Bulk density =1500 kg/m3

Average particle size = 395 micron

Resulting suspension velocity = 4,65 m/sec

sodium tripolyphosphate:

Na5P3O10

Material density = 2520 kg/m3

Bulk density =700 kg/m3

Average particle size = 250 micron

Resulting suspension velocity = 3.6 m/sec

Zeolite:

Na2Al2Si3O10-2(H2O)

Material density = 2000 kg/m3

Bulk density =500 kg/m3

Average particle size = 3 micron

Resulting suspension velocity = 0.35 m/sec

Horizontal length = 11 m

Vertical length = 14 m

3 bends

4” pipe

Altitude sea-level.



Calculation results (indicative estimates):

Calculation results:

Sodium Carbonate:

15 tons/hr at approx. 0.5 barg

Compressor volume = 0.2 m3/sec

air velocity = 18 – 29 m/sec

Sodium Carbonate velocity = 3.9 – 4.6 m/sec

Energy consumption = 1.72 kWh/ton

Sodium Sulfate:

15 tons/hr at approx. 0.41 barg

Compressor volume = 0.2 m3/sec

air velocity = 19 – 28 m/sec

Sodium Sulfate velocity = 4.8 – 5.6 m/sec

Energy consumption = 1.67 kWh/ton

sodium tripolyphosphate:

15 tons/hr at approx. 0.49 barg

Compressor volume = 0.2 m3/sec

air velocity = 19 – 30 m/sec

Zeolite velocity = 5– 6 m/sec

Energy consumption = 1.72 kWh/ton

Zeolite:

15 tons/hr at approx. 1.85 barg

Compressor volume = 0.2 m3/sec

air velocity = 8 – 24 m/sec

Zeolite velocity = 6 – 12 m/sec

Energy consumption = 2.67 kWh/ton

A compressor of 0.2 m3/sec (12m3/sec) at the 4” pipeline would bring the 15 tons/hr for all products.

The compressor has to generate a pressure below 1.0 bar for Sodium Carbonate, Sodium Sulfate and sodium tripolyphosphate.

For these materials a lobe blower is the best choice.

However, for the Zeolite, a conveying pressure of approx. 1.85 bar is required and this pressure requires the application of a screw compressor with internal compression.

(The reason for the higher pressure is caused by the higher Zeolite velocities as a consequence of the low suspension velocity, caused by the very small particle size (3 micron))

Conveying the Zeolite at lower airflows is possible, however, the pressure will be higher then.

The estimated installation, matches an ordinary bulk tanker installation.

The calculations indicate condensation, drying of the conveying air is required.

If you need more info, please let us know.

Best regards

Teus ■

Originally Posted by Teus Tuinenburg

Dear Neval,

Calculation results (indicative estimates):

Calculation results:

Sodium Carbonate:

15 tons/hr at approx. 0.5 barg

Compressor volume = 0.2 m3/sec

air velocity = 18 – 29 m/sec

Sodium Carbonate velocity = 3.9 – 4.6 m/sec

Energy consumption = 1.72 kWh/ton

Sodium Sulfate:

15 tons/hr at approx. 0.41 barg

Compressor volume = 0.2 m3/sec

air velocity = 19 – 28 m/sec

Sodium Sulfate velocity = 4.8 – 5.6 m/sec

Energy consumption = 1.67 kWh/ton

sodium tripolyphosphate:

15 tons/hr at approx. 0.49 barg

Compressor volume = 0.2 m3/sec

air velocity = 19 – 30 m/sec

Zeolite velocity = 5– 6 m/sec

Energy consumption = 1.72 kWh/ton

Zeolite:

15 tons/hr at approx. 1.85 barg

Compressor volume = 0.2 m3/sec

air velocity = 8 – 24 m/sec

Zeolite velocity = 6 – 12 m/sec

Energy consumption = 2.67 kWh/ton

Hi TT, i have read a lot of thread posted by you on pneumatic conveying and are pretty amazed of your experience in this field. Can you please show me how do you calculate to obtain those values ?

Do you have an email where we can communicate directly ? Thanks in advance ■

Dear SeventhEro,

Thank you for your interest.

The calculation algorithm is a result of many years (from 1981 – present) of mathematical evaluation of the physics of pneumatic conveying and correlating the mathematical description with many field tests.

The resulted knowledge and computer program (approx. 50 Mb now) are not available on the market.

Communication through the private messaging feature of this forum is possible.

Have a nice day

Teus ■

Dear Tues,

Thanks for still being around, your expert opinion is very much appreciated ■