The sodium salts you refer to are fiercely hygroscopic and should never have been pneumatically conveyed in the first place. Since they were, it appears that the air dryers are not up to the job. This is one of the most common failings. Many equipment suppliers provide systems which are contradictory. Alumina is conveyed pneumatically all over the world. People pay a fortune for dryers and when they fail the lines block. If they don't block they will wear out the bends...But they are the automatic first choice. I gave up decades ago! ■

Dear muhammadsial,

In your post, you mention to have a blockage problem while transporting soda ash.

To guide you in this matter, a lot more information is needed.

Assuming a pressure system.

Did the problem manifest right after taking the installation in operation?

Where are the blockages occurring?

In the first section of the conveying line or in the receiving filter?

Is the blockage occurring at high feeding rates (higher pressure)?

To start investigating the cause of the problem, a full description of the installation is required to calculate the performance. (Actually repeating the design calculation)

Also the ambient conditions are important, to evaluate the condensation problem.

Possibly, the recalculation already reveals the cause of the choking behavior.

The thread, you started with, is not enough to give you an useful answer.

To John,

I worked for a cement stevedoring company, which operated one of the floating pneumatic cement unloaders for an alumina transshipment project.

The floating unloader unloaded approx. 400.000 tons to 450.000 tons alumina per year over more than a decade.

The alumina was vacuum unloaded from a rhine barge and pressure discharged into a nearby silo.

From the silo, the alumina was transported by road tankers to the smelters.

The compressed air was not dried and we never had problems with condensation.

Bend wear was taken care of by wearing boxes on the outside of the bends.

The wear on the flexible hoses was higher than in cement, caused by static electricity.

Also the wear on butterfly valves was higher.

Generally, the pneumatic conveying installation performed satisfactorily.

Have a nice day ■

Sodium sulfate is basic ingredient in washing powder manufacturing and it is also very difficult

to convey pneumatically. It requires special conveying pipe line to get decent conveying rates.

Soda ash is also similar but is bit better.

As john has already mentioned they are both hygroscopic and can form lumps. But most of the

unloading stations on these plants have lump breakers installed. It is very likely that you have

changed suppliers recently and the PSD has changed . Hence blockages. if you can provide the

PSD data for original material and new material then some recommendations can be made. ■

Originally Posted by muhammadsial

Hi Everyone

I am having a problem at my plant where i am facing blockage while transporting the soda ash with a compressed air while the volume rate of sodium sulphate has also slowed down. please guide me in this matter.

Dear Sir,

From your brief write-up, it looks like you have a pressure type conveying system using compressed air from a central compressed air system. Most plants have 2 types of compressed air systems, one for general use, and the second called "instrument air" for operation of instruments. Instrument air has a very low dew point. For conveying sodium sulphate, you should be using instrument air.

Before feeding this material into the conveying line, make sure that it is fully purged with instrument air. This will prevent any humid air that is entrained in the voidage space of this material from entering the conveying line.

Best regards,

Amrit Agarwal

Pneumatic Conveying Consulting

Email: polypcc@aol.com ■

hi guys i got an excel sheet for the pneumatic conveying calculation can you guys please check whether its correct or not.i got it from google and did some editing in the equations.

https://drive.google.com/drive/folde...UQ?usp=sharing ■