No manufacturer routinely makes an agitator to disperse compressed air through the agitator shaft and blades. If you have enough money, lots of money, you may be able to find someone who will fabricate a custom agitator. I can't think of any reason why going to that much trouble, with both fabrication and operation, would be justified over other highly effective methods of gas dispersion. It sounds as if you are trying to duplicate a laboratory scale design, with self-induced gas dispersion. This idea is not recommended.