Dear Mr. Talreja, Soda ash is very higroscopic material in nature.There is a special type of discharge rotary valve below the hopper outlet which serves as a discharger cum lump crusher you can provide the same.If you have provided air cannons/shock blasters in your bin then always keep supply of dry air for their actions.

Anil Seth

Libran Engineering & Services

www.libranengineering.com ■

Soda ash is hygroscopic material and caking is very common in soda ash silos. The best solution is to have a gravity mass flow silo with a suitable discharger “First in first out” so that whole mass of material moves and no stagnant zones. But since you have mentioned you want to keep the existing silos this option might not be feasible.

Caking is assisted by high humidity levels in the silo and temperature changes (day-night cycle). You can install a dehumidifier to control the humidity of the air in the silo and for temperature changes you can lag / clad the silo. If you are pneumatically blowing material into air then using the dehumidifier on the blower also helps. ■

dear Talreja,

Lump formation in silos, storing hygroscopic materials, is often experienced, but the cause is not often discovered.

For sure is:

1-water is involved

2-The water is concentrated or accumulated at the location where the lump is formed

3-The water has entered the silo in some way.

Lump formation can prevented by keeping the water outside the silo.

Therefore it is important to know the entering path of the water and the way it can concentrate or accumulate at one location.

1-water can enter the silo through leakages. The lumps then will form underneath the leak or at the leak.

2-Condensation of water vapor from the air above the product in the silo. This water runs to the lowest point, where it drops off f.i. the ceiling in to the soda ash.

3-Condensation of water vapor from conveying or fluidization air above the product in the silo.

4-Condensation of water vapor from breathing air above the product in the silo.

5-Long term condensation at a location, where the material is not moving (dead spot), where condensed water accumulates over time. (f.i air slides, bin blasters etc)

Some of these possibilities can be estimated by calculation.

Listing all the possibilities of water coming into the silo and then investigate whether those possibilities can exist and estimate their influence on lump forming could be the first step in solving your problem.

After you have identified the possible causes, the next step is to find a remedy.

success

teus ■

The type of the unit doesn’t matter much as long as you define the duty properly. First ask your soda ash supplier for CRH (critical relative humidity) and keep the RH below it. If you want to dehumidify the silo only it will be a small unit and desiccant type should work fine. Since you are in tropics I recommend you should ask your local suppliers to assess the duty. ■