Dear m.shabkhosh,

Bentonite pneumatic conveying handling systems are often made for the offshore industry as “high pressure” systems at approx. 3.5 to 4.5 barg operating pressure.

The design pressure is then approx. 5.5 to 6.0 barg.

The high pressure is selected, because flexible hose connection diameters between a PSV and a drilling rig can be kept at 6” and still have an acceptable conveying rate.

High pressure bentonite conveying require the application of oil filled screw compressors with dryers.

High pressures cause condensation in the conveying lines of the conveying air is not dried.

High pressure conveying requires high pressure conveying tanks.

However, if the installation is land based, a low pressure system is preferred.

A tank system should then operate at approx. 2.5 barg and a screw-feeder system at approx. 1.5 to 1.8 barg.

In other words, the system to be designed depends on the application circumstances.

Before a system can be calculated, the operational requirements and routing needs to be known:

-bentonite properties (bulk density, particle density, particle size)

-conveying rate

-pipe routing (horizontal distance, vertical distance, number of bends or the exact geometric description of the routing)

-ambient conditions (pressure, temperature, RH, altitude above sea level)

I doubt sincerely that your reference will result in a reliable design calculation, as the underlying theory is mostly rather vague.

A lot of suppliers in this branch do not really calculate their systems, but use a kind of regression formula approach or only design their systems based on previously built installations

The design calculation(s) of such a pneumatic conveying system requires a calculation algorithm, which solves the relation between airflow, pressure and conveying rate and at the same time checks the chance of sedimentation and condensation in the pipe line.

The company Yarca pcs (http://yarca.nl/) uses such an extensive computer program, based on physical laws (Newton laws, gas laws, conservation of energy and including all components of the installation), which is used also many times for the calculation of bentonite and barite conveying installations (among others).

For a better indication of your system, let us know the above mentioned required information.

Have nice day ■

Bentonite I have come across is normally very fine powder.

Never had any problems with this one! I class It as a reletevely

easy material to convey both in lean or dense Phase. To get any

meaningful reply as our good friend Mr Tues has pointed out

material properties and a system design perameters are required. ■

Dear Mani,

From the installation description, I understand it is configured as shown in the attachment.

I also understand that there is an existing compressor.

What is the type and performance (volume and pressure) of this compressor?

Are there already pipelines with valves or diverters installed?

If so, what are the diameters of those pipelines?

Have you already decided for a feeder system? (single/double tank system, rotary valve, screw pump).

The calculation procedure www.Yarca.nl uses, is based on the physical laws s.a. conservation of energy, gas laws, Newton laws and thermos dynamics.

The algorithm is a numerical integration method in the time domain, which iterates to a consistent result.

I never came across a practical and reliable reference book for calculation and I doubt, that there exists one.

The attached PRELIMINARY calculations are to be considered as an indication.

The technical execution of a pneumatic conveying installation requires a full design process in which all aspects are evaluated, s.a. used components, controls, safety devices, etc.

Unless you are confident of yourself (which seems not to be the case, regarding your problem with your referenced “Pneumatic Conveying of Conveying of Solids”), I strongly advise to ask a reputable and experienced supplier for this project.

Have a nice day,

Attachments

calculation for bentonite (PDF)

bentonite storage model (1) (PDF)

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Originally Posted by m.shabkhosh

Hi, everybody.

We are going to design pneumatic conveying system for handling "Bentonite".

Does anybody have experience with this bulk material?

Our reference for design is "Pneumatic Conveying of Conveying of Solids" author "R.D Marcus" and I need your guide and experience for obtaining following items for Bentonit:

1. Min. Froude : Fr

2.Max. load ratio:

3.Pipe diameter calculation

4.Pressure lose

5.Air Requirement

Your cooperation in this regards would be highly appreciated.

===================================================================================

Dear Mani,

I have used dilute phase conveying for similar materials. For your design of this conveying system, you can use the method described in detail in my article "Theory and Design of Pneumatic Conveying Systems". This method is based on more than 50 years of work in the design and operation of pneumatic conveying systems.

The main issue is proper design of storage silos because this material is not free flowing and tends to arching.

Regards,

Amrit Agarwal

Pneumatic Conveying Consulting

email: polypcc@aol.com ■

Dear Mani,

You are more than welcome

Regarding the calculated routing, nothing changes with this exact description.

I attached the modified drawing.

The calculations, already made are for a 4” and 6” pipeline.

For a 5” pipeline, the resulting pressure will be between the already calculated pressures for the

4” and 6” pipeline.

The compressor size will also between the already calculated sizes.

A new calculation for a 5”pipeline can be made, if required.

- An airlock operates best at low conveying pressures, because of low leakage and low leakage velocities, minimizing wear.

- This implies larger pipe diameters.

- A Screw feeder, Fuller Kinyon pump, requires more energy.

- A tank system is more complicated and requires height to install

- A pressure pot system is also feasible, but is intermittent.

Leave the chosen installation to the suppliers and ask for their motivation to quote their solution.

This software is developed by me, and I am working on it from 1980, including the description of the physics and the used formulas and the technical aspects of the installations.

This software is unique and not available on the market.

Search the internet and use the list of bulk-online Leaders of this forum.

For general understanding how pneumatic conveying works, your reference book is OK.

For checking vendor data, you have to check vendor ‘s references.

Best Regards,

Teus

Attachments

bentonite storage model (2) (PDF)

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Dear Mani,

I made the calculation for a 5" pipeline as well.

See Attachment.

I understand that you are modifying or upgrading an existing installation.

This work needs to be organized as a project.

- Starting with the investigation of the present situation.

- Then the new requirements have to be defined.

- Pre-design new installations of various compositions of equipment

- Establish the use of existing equipment components

- Review the installation to bring the technology and controls up the nowadays standards.

- Write a specification

- Ask quotations.

- etc.

Success

Attachments

calculation for bentonite-vers-4-5-6 (PDF)

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Dear Mani,

Hope you are feeling better now.

I am not sure, what you mean by “a typical technical specification and data sheet”.

-In the preliminary calculations, the input variables describe the basic design of the installation.

-The calculation gives the output variables.

If the output variables are meeting the requirements, then the technical design and selection of components can start.

After the selection of components, the pneumatic conveying calculation has to be repeated with component variables.

If it is necessary to modify the design during the technical design process, then the calculations have to be repeated with the new input variables.

Have a nice day and success ■

Dear Mani,

The company TBMA is based in The Netherlands approx. 90 km from where I live.

The Pneumatic conveying specification sheet from TBMA is a good start to begin with.

According to their website, TBMA must be considered well capable of designing and delivering the components to your project.

The actual construction work, including the supply of the piping, should be done by a local company.

(Maybe under supervision of the vendor)

There are many companies in the world, who manufacture these kind of installations, especially for the offshore industry.

Ask those companies for an offer to you and supply them with all the information and pre-information, which you have.

And if a company needs more information, they will certainly ask for it. From the nature of the extra required information, the company 's skill can be estimated.

Carefully read their delivery conditions and try to get references.

Take care ■