Theoretically two gm moles of NaOH will absorb one gm mole SO2 . However many other factors have to be considered in scrubbing flue gas. The following two papers may be of help.
Assuming 1.3 kg/m3 Fluegas density and taking into account the properties of SO2 one gets 1.86 x 40 or about 75 kg NaOH consumption/hr.
Since the efficiency may be less than theoretical a bit more maybe needed.
This is a back of the envelope kind of quick and dirty calculation. If commercial issues are involved better get it checked.
Actually you will need more than that amount. 75 kg/hr is the theoretical amount of Naoh needed to absorb the amount of SOx that is present in the flue gas as specified.
You are talking about cleaning 546 tons of flue gas in a day.
Room temperature water can absorb 0.2 kg SO2 . So 300 litres water can absorb 60 kg SO2. This translates to only 7200 litres water per day.You have to throw away this water subject to local environment laws. You can completely avoid using NaOH.
Since you said something about 12000 litres water you may not need any NaOH.
thanks for your response sir,
but our procedure is like we are adding naoh into 12000 ltr water and maintaining its ph value 10-12 ph. and this solutions we will spray on scrubber tower which convert sox into sulphuric and sulphuras acid.
and we must have to add naoh in water and solution spray in tower with number of nozzles by using 15 hp centrifugal pump. so there is any calculations or according your experience how many naoh required?
If your requirement is only pH maintenance 4.8 kg NaOH in 12 m3 water will give a pH of 12 as you mentioned before.
But the chemical reaction between SOx and NaOH does need 75 kg NaOH/hr for the contamination level you have given. I am unable to suggest a way around that.
@Sagar Jiyani , I am writing from just the chemistry point of view. I have not done anything on flue gas scrubbing.We id have a small incinerator at work for bio waste, which had a scrubber for washing the exhaust gases from bio waste combustion, which did not have much SOx. We just used waterspray more to cut down dust and smoke. It has been working for many decades now.
There are stringent environment regulations now on flue gas emissions. You have to conform to applicable rules. One option that may be cheaper is to use a spray tower with limestone powder slurry.
Please see these links: https://en.wikipedia.org/wiki/Flue-gas_desulfurization
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