Patent ID: 9493364
Filing Date: 2016-11-15
CPC Classification: C01B,C01C,F28D,Y02E

Claim Text:
1. A method for producing ammonium nitrate, comprising: providing a non-explosive gaseous oxidiser feed comprising ammonia, steam and an oxidising gas to a reactor; in the reactor, oxidising the ammonia of the non-explosive gaseous oxidiser feed to produce a reaction mixture comprising nitrogen monoxide and water vapour; providing the reaction mixture to a heat exchanger; in the heat exchanger, cooling the reaction mixture and conducting a reaction-absorption process in which (i) the nitrogen monoxide is oxidised to produce one or more oxidation products, (ii) the water vapour is condensed to liquid water and (iii) the one or more oxidation products react with and are absorbed by the liquid water to form nitric acid in a nitric acid stream, wherein substantially all of the nitrogen monoxide in the reaction mixture is converted to the nitric acid in the nitric acid stream, and wherein the concentration of nitric acid in the nitric acid stream is from about 20% to 40% on a weight basis (w/w); providing the nitric acid stream to an additional reactor; and in the additional reactor, reacting the nitric acid in the nitric acid stream with ammonia to form an ammonium nitrate solution comprising the ammonium nitrate and water, wherein heat available from the reaction mixture above its dew point is sufficient to concentrate the ammonium nitrate solution to a concentration of about 75% to 85% w/w upon application to the ammonium nitrate solution, and wherein water that is evaporated from the ammonium nitrate solution is recycled so as to comprise at least a portion of the steam of the non-explosive oxidiser feed.