How to calculate proper compressor size
asked 30 May 2017 asked by Yakoub (420 points)
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.