I have a compressor that is on its last legs (it's more than 40 years old), and I am in the market for a new one.
We use it to oxidize iron, so I need to be able to produce a specific mass of oxygen (O2) and therefore automatically provide a specific flow.
That is the background info.
According to my research, the aeration basin into which the air is injected has an average concentration of Fe2+ iron on the order of 53 kg per hour. My calculations indicate that to oxidize this amount, we need 7.5 kg of O2 per hour. As a result, based on this mass, I calculated the flow rate for the injection at 81 m3/h.
I would like to know if my calculations are right. This is not exactly in my wheelhouse, so can anybody out there confirm or refute these numbers?
The compressor in question pretty old, and that is where I have found the problem lies, since my supplier does not have the technical specs on this particular equipment. The machine dates back to 1974. I don't have access to an engineering firm and could use your help.
Thanks in advance.
What type of water and what flow rate? The hourly amount of iron seems huge compared to what is commonly encountered in drinking water facilities.
And, can you tell us if after you oxidize, you use filters? If so, can you describe the process?
We are talking about industrial effluent.
At the aeration basin inlet, we have a certain concentration of iron as well as hydrochloric acid. But by adding lime, we can increase the pH and create water.
Everything is OK in the basin and meets regulatory standards. However, I'd like to know if my calculations are correct. I have a background in mechanics but the wastewater industry really interests me. Not being an expert, I'm looking for advice on my vintage compressor.
The flow rate is very variable: it can go from 18.5 m3/h to 0.
I would like to improve the system, but my first task is to change the compressed air unit.
It is very hard to answer your question:
-The addition of lime helps neutralize the acid but also transforms the iron into insoluble hydroxide: 2 FeCl3 + 3 Ca (OH) 2 = 2 Fe (OH) 3 + 3 CaCl2, so it is difficult to calculate the air required for complete oxidation.
- We would need to know the oxygenation output. When you introduce a certain amount of air into a liquid, only a portion gets dissolved as a function of temperature, height, size of the bubbles, and features of the effluent.
It might be interesting to measure the concentration of dissolved oxygen in the basin. If there is oxygen saturation (consult a chart of corresponding temperature and salinity), this means that the compressor could be replaced with a lower airflow.
If the current treatment is adequate and you are unsure of your numbers, it is probably best to replace the compressor with a unit that delivers the same flow rate.