Dear Mr Jade

These are the questions I enjoy

But to make a preliminary calculation, I need some more information of the product and pipeline.

What I miss is :

-material density (to estimate the floating velocity)

-angle of repose

-vertical distances in your pipeline, upwards and/or downwards.

-If possible the name of the product ( It could be that I have (some) experience with it)

As I have a program, that calculates dilute phase conveying, it is then rather simple to estimate an installation for you.

(see also “Unloading Fly Ash from bulktanker” from mr bharat)

Looking at the distance of 700 m, which indicates a very low loading ratio, I have the feeling that the calculation of a dilute system (pneumatic conveying seems to be possible) will show a huge installation for only a 12 tons/hr performance.

This transport of 12 tons/hr can also be achieved by 1 bulktanker.

Looking forward to your reply

best regards. ■

Have you considered a pipe conveyor?

Joseph A. Dos Santos ■

For a fine powder, low velocity dense phase conveying is nearly always the best solution, almost regardless of material density. With a mean particle size of 106 micron, however, I doubt if your material is fine enough to convey naturally in dense phase. This is one of those cases where you would need to undertake tests with a sample of your material if you really wanted to convey in dense phase.

Conveying distance is also a problem, and particularly with so many bends in the pipeline. Dense phase conveying of powders requires the material to be conveyed at a relatively high solids loading ratio and this, in turn, requires a relatively high pressure gradient. With such a long pipeline a very high air supply pressure would be required.

If the material is conveyed in dilute phase, and it is very abrasive, then you will have a major problem with erosive wear of bends in the pipeline. Suitable bends will add significantly to the cost of your installation. It is a simple duty to convey 12 tonne/h over 700 m with a pneumatic conveying system. Whether it is the best system for the duty is another matter. Compare the costs of the alternative pipe conveyor and bulk tanker and take operating and maintenance costs into acocunt as well as capital cost. ■

You need to carry 6.4m3 700m in 1 hour. With a conveyor you must construct a supportive structure. Floor space might be lost to the structure supports & this might influence other operations.

Whatever you use the system will require space for loading & receiving equipment.

To eliminate the abrasion wear associated with pneumatic conveying you might consider IBC,s (say 24 x 500kg) & carry these by overhead power & free conveyor or on a simple fork truck.

The road tanker might not be able to negotiate the bends mentioned.

A pipe/belt conveyor would have a carrying cross section of 0.0018m2 @ 1m/s. Would a suitable structure be justified?

With the pipe conveyor you will have to extend the dedusting paraphernalia over a considerable distance & that might increase your power consumption dramatically.

If the envisaged process can produce bottlenecks at either end then you have to accommodate the surges. This is comparatively easy with IBC's; you just dangle more off the powered & free conveyor. ■

If you consider a high pressure (>1.0 Barg) dilute phase conveying system, the most efficient design will have multiple segments of graduating pipe diameters. Most likely, you will need to feed the system with dual pressure tanks. High pressure rotary valves may be more economical, but may not hold-up to the abrasive material. Make sure that you have a expert, with experience in stepped diameter systems design the system for you. ■

Dear Mr Jade

I am still interested in your reply abt material properties and routing.

Then I am possibly able to explore the pneumatic option

hear from you ■

Mr. Jade

You have received a wide spectrum of advice and comments from our forum members, all of which make sense in their own way.

Your problem, while relatively simple from a duty stand point, is more complex then you may realize due to the distance and pipeline geometry. One suggestion which I don't recall seeing is to consider booster stations along with stepped pipe lines.

The right solution is not a quick and clean decision, but requires an in depth comparison and evaluation.

Our firm has been in the business of helping people like yourself evaluate alternative ideas, making cost comparisons which include capital as well as longer term operating costs for nearly twenty years.

If you would like some assistance along these lines, please send me an e-mail to the address below and we would be happy to make a proposal for you to consider.

Regards, ■