The subject of how to increase the capacity of pneumatic conveying systems is covered in detail in my article in the April 2004 issue of Chemical Engineering. I will be glad to send a PDF copy if you don't get this magazine.

Regards,

A. T. Agarwal

Consulting Engineer

polypcc@aol.com ■

Mr. Ahmed Ali,

I have read and found the article by Mr. Amrit Agrawal , very useful to understand the likely bottlenecks in lean as well as dense phase conveying and measures to take care of these bottlenecks.

Good luck.

AKSanghani ■

Dear Amrit may I have a PDF copy of the your article?

regards

debashisde@in.dclgroup.com ■

Debashisde,

I have emailed a copy to you.

Amrit

A. T. Agarwal

Consulting Engineer

polypcc@aol.com ■

Dear Lexter,

My article "Theory and Design of Pneumatic Conveying Systems" will be published in a well-known magazine very soon. This article will help you in analyzing the effect of bends and pipe length, and also of other variables, on conveying system's capacity. This article should be helpful to you if you can wait until it is published. In the meantime, I will be glad to run calculations for you if you send me details.

Regards,

Amrit T. Agarwal

Consultant

Pneumatic Conveying Services LLC

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Could you please email me your papers?

Debottleneck pneumatic conveying systems

Theory and Design of Pneumatic Conveying Systems

my email: shengming.tan@studentmail.newcastle.edu.au

I need your papers as my references in my thesis.

Thanks.

■

This article was published in the April 2004 issue of Chemical Engineering. I think you can access this magazine through your library. If you can't, please send an e-mail to me and I will then send you a PDF copy.

Regards,

Amrit T. Agarwal

Pneumatic Conveying Technologies LLC

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

I was able to read the abstracts and text from our online library. However, all of the figures are omitted and I could not get the completed copy of your paper. So please email me one. Thanks.

■

As requested a copy of the article has been emailed to you. If you work with Peter Wypych, please give my regards to him.

Amrit Agarwal

Consultant

Pneumatic Conveying Technologies

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Actually, I stay in Newcastle University and Prof Mark Jones is my supervisor, where Peter is in Wollongong Univeristy and 300km away from my university. Thanks for yoru paper.

■

Dear Mr Agrawal,

I would like acopy of you article above.

epoegy@yahoo.com

Freddy Dawoud

EPO, Consultants ■

Dear Freddie,

I will be able to send a copy of this article only after it has been published. It is expected to be published in Powder Handling and Processing magazine in February 2005.

In the meantime, let me know if you need any help.

Regards.

Amrit T. Agarwal

Consultant

Pneumatic Conveying Technologies

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Dear Ramesh,

You seem to have two problems, poor regulation of conveying velocity and poor materials of construction. These have been covered in many articles and books. You can find solutions if you study them.

Alternatively, let me know if you need our help.

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Technologies

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Mr. Agarwal:

Can I have a copy of this article?

Thanks.

Pravin

ppatel@labtops.com ■

One other possible option is to reduce air flow (and make more pressure available for conveying product) - as long as you are not operating close to minimum transport. However, conveying characteristics for large capacity systems are fairly "flat", so benefits here may be minimal. If the pipeline is long, you also could look at stepping up pipe size towards the end. I do not think that you have to reduce pressure loss significanctly to get the extra 10 t/h.

I presented a cement modelling paper at the Powder Show (Chicago) in 1992 - this could help you find some answers (for free).

wypych@uow.edu.au ■

The problem this gentlemen has isn't the pipeline from what I can tell in discussions with himself and others at his cement plant. The line pressure at the present capacity is basically what we would predict for a typical screw pump system, operating in the two-phase flow regime.

I believe, from what I can gather, the pressure losses between the air manifold on the pump and the compressor discharge may very well be too great and there isn't sufficient pressure left to convey the additional material.

This first assumes the pump has the capability to deliver the increased flow rate into the system. I've seen plenty of screw pump systems where the pump is rated for a specific capacity but the suppliers always assume a certain loose bulk density for Cement, as the screw pumps are volumetric devices. When the cement is lighter in weight, the nominal capacity in TPH has to be derated accordingly.

There are many other factors which could be contributing to the shortfall in their capacity but the end user is reluctant to have someone with the proper experience and knowledge visit the plant to help them. ■

Theory and Practice for Increasing the Capacity of Pneumatic Conveying Systems are described in detail in my article published in the April 2004 issue of Chemical Engineering. As discussed in this article, we have mainly 4 reasons that prevent a capacity increase: pressure, velocity, feeder, and system design. From what I have learnt in this case, capacity is limited by the feeder and there is no easy way to fix it. One possibility is to add and blend a flow-agent to improve the performance of the feeder, but this change is expensive. Another is to install a small additional feeder in parallel. Any other ideas?

Regards,

A. T. Agarwal

Pneumatic Conveying Consulting Services LLC

polypcc@aol.com

Ph and Fax:304 346 5125 ■

It's possible the original screw pump manufacturer, CPAG, has a screw with adequate pitch and compression to handle the higher capacity requirements they are looking for. If not, the next step, as you suggest, is an expensive one.

By the way, if you have a .pdf version of your paper, can you forward it to me?

thanks ■

Dear Jack,

As requested, I am sending a PDF copy of this article to you. Let me know if you have any comments.

Regards,

A. T. Agarwal

Pneumatic Conveying Consulting Services LLC

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Thanks Tim

I'll do that

Jack ■

Jack, I need your email address for sending this article. You may also give me your phone number.

Regards,

A. T. Agarwal

Pneumatic Conveying Consulting Services LLC

polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Tim

I will forward it to you

thanks again

jack ■

Provided that the air supply pressure is above about 0.8 bar gauge, or 0.4 bar vacuum for a negative pressure system, stepping the pipeline to a larger bore part way along its length will generally guarantee an improvement in performance, provided that the step is correctly located and that an increase in material flow rate can be achieved by the feeding device. An alternative to this, if you do not want to step the pipeline, is to extract air from the pipeline part way along its length. An article of mine on this subject will be found in the latest issue of Bulk Solids Handling [Vol 24 (2004) No 6]. A comparison is presented of single bore, stepped pipelines and air extraction systems and the conveyed material considered is cement. Air extraction, of course, is only applcable to positive presure conveying systems. ■

Dear Loyal,

Please send me an email requesting this article.

Regards,

A. T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services LLC

Email: polypcc@aol.com ■

Paulus

Adding more air is not a sure fix for a capacity problem. It sometimes helps but many times it results in less capacity. The extra air volume has to be handled and friction losses are significantly increased as they are a function of the square of the air velocity.

As friction losses increase, the available pressure remaining to impart energy to the matetrial is decreased and therefore capacity suffers.

Wet air can definitely have an impact on the conveying system. Product characteristics will change and build ups in the line will most likely begin to take place.

Adverse effects at the discharge end relative to caking of the filter media can alo begin to take place.

Regards ■

Mr. Agarwal

May I get the copy of PDF file from you?

Thanks ■

Dear Shenjie,

I will be glad to send you a PDF copy of my article on the above subject. Please send your request to me at the email address given below:

Amrit T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■