Reverse Osmosis to Concentrate Ammonium Nitrate in Condensates, from Laboratory Studies to Industrial Scale Design and Operation

In the manufacturing of ammonium nitrate, a condensate containing ammonia and ammonium nitrate is obtained. The concentrations of these species are in practically all cases too high for direct discharge into a water recipient. At some plants, some of the dilute ammonium nitrate solution can be spread out on adjacent farmland, as it is a fertilizer, but commonly, nitric acid is added to this stream to convert all the ammonia to ammonium nitrate, and this stream or part of it is concentrated in a separate evaporator, here called the low concentration evaporator. When the existing low concentration evaporator has reached its capacity limit, the manufacturing plant has to spend some capital to increase its condensate treatment capacity. Pre-concentrating the ammonium nitrate condensate with reverse osmosis (RO) is one way to accomplish this.