3 replies to this topic

[Monica_Staff]

Hi,
I am new to the forum but have been reading for quite some time. I must admit this is a valuable and impressive resource, and I would like to thank you in advance for the help.
Now to the question. I am trying to calculate the amount of sodium hypochloride fugitives from loading a truck. I am assuming it takes 30 minutes to load and that the temperature of the liquid is 60oF. I've been browsing the EPA website for any models that might closely represent the situation. I understand that given the conditions if I try to model the event, I will end up having transient mass transfer (depending on variable volume of liquid as time progresses) into the air. Has any one come accross a model that could be used in this case?

Again thank you and have a good one.

[djack77494]

Monica,

If I correctly understand your question, then you are loading a tank truck with an aqueous solution of sodium hypochloride. Your solution is at 60oF, and so your water vapor pressure will be pretty small; the vapor pressure of sodium hypochlorite will be virtually nil.

I'm not sure what mechanism would produce fugitive emissions in this case. The only thing I can think of would be entrainment of your liquid solution. Your have a volumetric flowrate of air leaving the truck during the filling operation. If you can somehow estimate how much entrained liquid (solution) is carried out with the air, then you would have your estimate. I know of no correlations/equations/standards that provide a way of doing this, but would be interested in hearing of a solution.

Good luck,
Doug

[Monica_Staff]

Doug,
Given the conditions I am aware that the emissions are so small they can be neglected. However I need to know and show that my facility is not breaking any rules. I did come across a document (rather old by the way) that suggests a way to estimate emissions ("Control of Volatile Organic Compound Emissions from Batch Processes-Alternative Control Techniques Information Document"). The terminology (VOC) might be a little misleading; however after reading the paper I am positive about the applicability of the equations to my situation. I found out none of the models (software) on the EPA website can be applied.
By the way, thanks for replying and have a good one.

[djack77494]

Monica,
If you're just looking to document a rate of emissions, find the vapor pressure of sodium hypochlorite at your operating temperature. Estimate a rate of inbreathing and outbreating for your tank. This is based on normal heating/cooling throughout the day plus venting due to transfers of solution into and out of the tank. Gases vented from the tank will have a concentration of NaOCl that is approximately the vapor pressure of NaOCl in psia divided by atmospheric pressure (14.7 psia). Multiply that fraction times the total outflowing gases to get the amount of released NaOCl. My guess is that it will be an extremely small number.
Doug