# SO2 scrubbing with NaOH aquas solution

1. Oct 9, 2014

### HP Raj

Hi friends, as part of my research work, I need to scrub off the SO2 content in the exhaust flue gas from a tubular furnace in my lab.

I got the information about the usage of NaOH aquas solution for the SO2 scrubbing.

Could you please suggest the ratio of water and NaOH that would be mixed together.

The flow rate of the exhaust gas mixture is 200 ml/min. The SO2 content in the gas mixture os 0.25%.

2. Oct 9, 2014

### Staff: Mentor

This is more chemical engineering than just chemistry.

3. Oct 9, 2014

### HP Raj

Hmmm, could you please suggest an approximate ratio....

4. Oct 10, 2014

### Staff: Mentor

It depends on the setup. How is the contact being carried out?

Chet

5. Oct 12, 2014

### HP Raj

We are planning to bubble the exhaust gas which contain SO2 through the NaOH solution in a container.
The flow rate of the exhaust gas is 200 ml/min.
The 'ppm' (Parts Per Million) of SO2 in the exhaust flue gas is 5.26.
But, the allowable ppm for SO2 is below 5 ppm.
I don't know in what ratio we need to mix the water and NaOH for scrubbing the SO2 from this exhaust flue gas.

6. Oct 13, 2014

### Staff: Mentor

As Borek said in #2, this is a chemical engineering problem involving convective mass transfer and interphase equilibrium near rising bubble interfaces. Hire a chemical engineering consultant to help you.

Chet

7. Oct 14, 2014

### Hyo X

If you are already at 5.26 ppm, and you want <5 ppm, you are pretty close. The most NaOH in water you can get is 50%, a saturated solution. At that concentration you will have some salt precipitation if any water evaporates.

So try 25-40%. NaOH in water

8. Oct 15, 2014

### HP Raj

It means, for 1 ltr of water, we can go for 250 - 400 g of NaOH. Am I rt?

9. Oct 15, 2014

### HP Raj

It means, for 1 ltr of water, we can go for 250 - 400 g of NaOH. Am I rt?

10. Oct 15, 2014

### Staff: Mentor

Not exactly, but most likely close enough.

11. Oct 16, 2014

### HP Raj

Friends, could you please let me know the solubility of K2SO4 and Na2SO4 in water at room temperature....

12. Oct 16, 2014

### Staff: Mentor

Have you tried wikipedia?

13. Oct 16, 2014

### HP Raj

Yes, but in that, they have given the solubility at 20-25 Deg. C.
Can we consider this as the solubility of these chemicals at room temperature?
Am totally confused......

14. Oct 16, 2014

### Staff: Mentor

20-25 deg C is a room temperature.

Any decent chemistry handbook will contain solubility tables, typically for different temperatures. Mine definitely has them.

15. Oct 27, 2014

### HP Raj

Friends, if we know the individual melting point of the compounds, is there any way to find out the eutectic temperature of the mixture of these compounds?
Thank you for the information....it worked well...

16. Oct 27, 2014

### HP Raj

Hi friends,
If we know the individual melting point of certain compounds, is it possible to find out the Eutectic temperature of the mixture of these compounds?

Could you please help me to find out the Eutectic temperature of the mixture contains K2SO4, Na2SO4, Fe2O3, Al2O3 and SiO2

17. Oct 27, 2014