Dear Mr Hemant Apte,

I assume that you are referring to the use of an ordinary pneumatic bulk truck.

Let us assume that the tank volume is 45 m3 and that there will be approx 30 tons of flyash loaded.

Fly ash 30 micron

For a proper air velocity in a 130 mm pipeline, approx. 0.2 m3/sec of compressor displacement is required.

Calculating the installation, which you propose, the result is

pipeline capacity : 53 tons/hr at 2.0 bar

system capacity : 46 tons/hr (including pressurizing time and purge time)

To achieve 60 tons/hr the following configuration could be chosen:

Compressor displacement 0.25 m3/sec at 2 barpipeline diameter = 150 mm (6”)

pipeline capacity : 68 tons/hr at 2.0 bar

system capacity : 59 tons/hr (including pressurizing time and purge time)

If further system parameters are required, please let us know

have a nice day

Teus ■

Dear Mr Hemant Apte,

The cement conveying installation, which you describe,

should be capable of approx. 75 tons/hr at 0.4 bar

The 2 lobe blower cannot deliver more than 0.4 bar and is therefore not an option for a 2.0 bar to 2.5 bar designed system.

If you insist on using the 2 lobe blower of 1 m3/min for the fly ash installation, then you have to design the system for 0.4 bar.

The tanker can be designed for 2.5 bar, but will only be used for 0.4 bar.

The tanker outlet must then be 250 mm diameter as well as the pipeline.

The pipe line capacity in fly ash will be approx 85 tons/hr at 0.4 bar.

The filter installation and the safety valve of the silo must be adapted for the higher air volume of 1 m3/sec.

Using a 6 bar compressor of 1000 m3/hr # 0.278 m3/sec for the fly ash installation could be possible in combination with a 6”pipeline.

If you are referring to an oil filled screw compressor as usually used as plant air compressor, which is automatically controlled, there should be no problem as this is already done many times before. ( check the suitabilty before deciding)

Behind the compressor there must be installed a pressure reducer for the same air volume and set at f.i. 2.2 bar and on the air delivery pipe line there must be a safety valve set at approx 2.5 bar.

The fly ash pipe line capacity will then be approx. 68 tons/hr and the system capacity approx. 60 tons/hr

success

Teus ■

Hi Teus,

Would Apte not automatically also run into a potential water drop out issue (especially if the plant air is not treated) when he goes from 6 down to 2.5 Bar? I would be worried about product caking up in the conveying line.

Hi Apte,

How much operating time do you accrue on the tanker truck conveying system? If there is a lot of usage you may still be able to save money in two ways: For one you should evaluate if you have to add another plant air compressor to your system in order to stay afloat with your demand as you operate the truck system. On the other hand, compressing to 6 Bar and than "only" using 2-2.5 Bar can be wasteful when compraed to a sinmgle stage oil free screw compressor. Cross your t's and dot your i's by carrying out a detailed ROI sutdy. Power consumption is often overlooked but is often greater than 75% of your total compressor life cycle cost. ■

Hi Ralf, Hi Apte

An oil filled screw compressor will also be equipped with an oil/water separator and cooler.

This will create water condensation, which will be drained by an automatic water drain.

Also a refrigerant cooler can be installed.

This installation delivers drier air compared to an oil free screw compressor without cooler and condensate drain.

Both compressors are used f.i. for cement conveying and I never experienced nor heard anything about real condensation problems.

About killing energy when using a 6 bar compressor, reduced to 2 bar pressure by throttling, you are right. That is an economical choice.

Best regards

Teus ■

Hi Teus,

Normally plant air machines should also comprise a air treatment systems. A great portion of USA cement plants I have been to had either issues with their air after treatment apparatures, or in some dedictaed oil flooded screw pneumatic systems were missing altogether. That can result in a high water content in the plant air system. If his system is in working order there should not be further water knock out at the conveying line. ■

Hi Ralf,

If a plant air compressor with air treatment is used for delivering air to a pneumatic conveying system, there should be no problem at all, apart from the energy waste.

For delivering plant air, it is crucial that the air is properly treated, because there will be much more water condensation due to the higher pressures and the condensed water will harm the pneumatic tools, operating on the plant air.

As I always worked with Aerzen compressors and blowers, I am in favour of oil free screw compressors and blowers with or without pre-inlets for pneumatic conveying applications.

Simple and reliable equipment.

That is also the reason that I incorporated the Aerzen compressor gamma in my calculation program. Thanks to the helpful attitude of Aerzen.

By the way, I made a Visual Basic program to calculate water condensation in air.

If you are interested, I can e-mail it.

Have nice day

Teus ■

Hi Teus,

Agreed. Every plant air system should have an after treatment system and it should be maintained in working order. As long as that is the case nothing should happen. Emphasis on the word "should".

I think you were so kind to e-mail me the moisture drop back in February (you are just as helpful!). No need to e-mail it again unless you updated the file. Thanks! ■

dear apte sir can i have your contact details to discuss this .

u may send the same at sanjayagarwal@parthengineering.net

my cell no is 09313055226

warm regards ■

Dear Sirs,

I need to install Pneumatic conveying System for Cement and Fly ash over a Distance of 3000 Mts. Capacity would be 80 Ton Per Hour.

Could any one guide me how to proceed on this and the critical design factors associated with this.

Regards

Subbs ■