Process and equipment for nitrogen oxide waste conversion to fertilizer

A process for converting an aqueous stream containing nitrogen oxide products to a liquid fertilizer composition comprising the steps of:

• a) directing said stream to a first contact zone,
• b) exposing said stream to hydrogen peroxide which is present within said first contact zone to convert at least some of any oxy acid(s) of nitrogen other than in the nitrate form present to nitrate ions,
• c) sampling said stream within said first contact zone to determine the relative amount of hydrogen peroxide by i) directing a sample containing hydrogen peroxide to a second contact zone;
• ii) adding sodium hypochlorite to the second contact zone;
• and iii) measuring the pressure of oxygen generated in the second contact zone;
• d) adding hydrogen peroxide to said first contact zone when said sampling determines there is less than an excess of hydrogen peroxide in said solution, and
• e) adding a solution comprising potassium hydroxide to said first contact zone to maintain a pH between 5.0 and 11.0 within said first contact zone and to form a solution of potassium nitrate.

A process for converting vapor streams containing at least one oxide of nitrogen therein to a liquid fertilizer composition comprising the steps of:

• a) directing a vapor stream containing at least one oxide of nitrogen to a first contact zone,
• b) contacting said vapor stream with water to form oxy acid(s) of nitrogen from said at least one oxide of nitrogen,
• c) directing said acid(s) as a second stream to a second contact zone,
• d) exposing said second stream to hydrogen peroxide which is present within said second contact zone to convert at least some of any oxy acid(s) of nitrogen other than in the nitrate form present within said second stream to a nitrate ion,
• e) sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide by i) directing a sample containing hydrogen peroxide to a third contact zone;
• ii) adding sodium hypochlorite to the third contact zone;
• and iii) measuring the pressure of oxygen generated in the third contact zone;
• f) adding hydrogen peroxide to said second contact zone when said sampling determines there is less than an excess of hydrogen peroxide in said second stream, and
• g) adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 5.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate;
• h) removing said solution of potassium nitrate from said second contact zone.

An apparatus for converting vapor streams containing at least one oxide of nitrogen therein to a liquid fertilizer composition comprising:

• a) means for carrying a vapor stream containing at least one oxide of nitroaen to a first contact zone,
• b) means for providing water to said first contact zone to form oxy acid(s) of nitrogen from said at least one oxide of nitrogen,
• c) means for directing said acid(s) as a second stream to a second contact zone,
• d) means for providing to said second stream hydrogen peroxide within said second contact zone to convert at least some of any oxy acid(s) of nitrogen other than in the nitrate form present within said second stream to nitrate ions,
• e) means for sampling said stream within said second contact zone to determine the relative amount of hydrogen peroxide within said second contact zone,
• f) means for adding a solution comprising potassium hydroxide to said second stream to maintain a pH between 5.0 and 11.0 within said second stream within said second contact zone to form a solution of potassium nitrate, and
• g) means for removing said solution of potassium nitrate from said second contact zone.