[nobushi]

Hello.


First of all, I am new to the forum and I don't know if this is the right section to post my doubt since I am still an engineering student. Moderators please feel free to move if necessary.

I am an intern at a chemical factory that produces chemical intermediates to other industries (B2B).
I am responsible to analyze and study the operation of the Spray Dryers that dry Sodium Dodecylbenzenesulfonate (SDBS). At the end of this three-month internship I must propose improvements to the enterprise, aiming to increase powder production.

The equipment is described as follows:

    Two-fluid nozzle atomizer
    Indirect air heating (thermal oil radiator)
    Cyclone and bag filter to collect powder
    Open cycle design
    Liquid solution (SDBS) to dry
    Compressed air to atomize

The image below from GEA Niro represents well the equipment:



I am exhaustively studying the equipment and the operation at the internet and in some books too, but the informations are a bit confusing and too much disperse.
I have visited a couple of days ago another industry that has spray dryers too (food industry), and the person in charge of the SDs gave to me some advice:

    Increase air flow
    Increase inlet air temperature
    Increase feed temperature
    Increase concentration

And also a modification to the SD: our equipments have one-point powder discharge (air and powder go to the cyclone together, where they are separated. The product is collected at the bottom of the cyclone and the air goes to a bag filter to retain the fines).
The recomendation was to create an air outlet after the cylindrical drying chamber, in the cone. So the most part of the powder would be collected just at the bottom of the SD an the air with fines goes to the cyclone. Therefore the powder separation would be increased and much less product goes to the bag filter.

What are your opinion about this? Are these recomendations valid, or is something else better?


Thank you very much!

[Wald_ron]

You could have more than one feed and chamber. I bet that's your limiting step.

[nobushi]

You could have more than one feed and chamber. I bet that's your limiting step.

Hi, thanks for the answer. But I think that our equipment is actually underused. Here are some data from the operation:

Spray dryer:
Height: 10 m (only cylindrical part)
Diameter: 3 m

Air (inlet):
Ambient temperature: 20°C
Inlet temperature: 235°C
Outlet temperature: 98°C
Flow: 20 m³/min (at air inlet)
Air inlet area: 0,78 m²
Relative humidity: 85%

Air (compressed):
Pressure: 2 kg/cm²
Temperature: slightly above ambient

Product:
Inlet temperature: 70°C
Flow (liquid): 260 L/h
Production (solid): 140 kg/h

[pikab00m]

What if you try to combine two elements into one so you can remove one of the steps. I suggest redesigning the shape of the drying chamber into a helycoidal one, bigger drying surface(as the substance moves forward) if I'm not wrong.
You could try a shape with some inner panels that will make the vortex happen.
Also, increasing the drying air pressure wouldn't that fulfill the role of the cyclone?
What you think about it?

I'm a student as you are, no internship though . I hope it helps!