Urea ammonium nitrate production comprising condensation

Patent metadata

Field	Value
Publication number	US-10370326-B2
Application number	US-201615573452-A
Country	US
Kind code	B2
Filing date	Dec 21, 2016
Priority date	Dec 21, 2015
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

The invention relates to a process for the production of urea ammonium nitrate, a system and a method of modifying a plant. The process comprises subjecting ammonia-containing off-gas resulting from the production of ammonium nitrate (AN off-gas) to condensation under acidic conditions so as to form an acidic a acidic scrubbing liquid in a finishing treatment section having a gas inlet in fluid communication with a gas outlet of a finishing section of a urea production unit, wherein the finishing section is adapted to solidify urea liquid, and wherein said finishing treatment section is adapted to subject ammonia-containing off-gas of the finishing section to treatment with an acidic scrubbing liquid.

First claim

The invention claimed is:

1. A method for the production of urea ammonium nitrate comprising
(a) subjecting ammonia and carbon dioxide to urea forming conditions so as to obtain an aqueous urea solution,
(b) purifying the aqueous urea solution in a recovery section to remove residual ammonium carbamate so as to form a purified aqueous urea solution, and optionally subjecting at least part of the purified aqueous urea solution to evaporation so as to form concentrated urea liquid,
(c) subjecting ammonia and nitric acid to ammonium nitrate forming conditions so as to form an aqueous ammonium nitrate solution;
(d) combining said aqueous ammonium nitrate solution and at least a part of the purified aqueous urea solution and/or concentrated urea liquid in a urea ammonium nitrate section so as to obtain an aqueous solution of urea ammonium nitrate;
(e) subjecting ammonia-containing off-gas resulting from the production of ammonium nitrate (AN off-gas) to condensation under acidic conditions so as to form an acidic condensate, and using at least part of the acidic condensate as an acidic scrubbing liquid in an off-gas treatment section downstream of a urea finishing section, said off-gas treatment section having a gas inlet in fluid communication with a gas outlet of said urea finishing section of a urea production unit, wherein the urea finishing section is adapted to solidify urea liquid, and wherein said off-gas treatment section is adapted to subject ammonia-containing off-gas of the urea finishing section to treatment with an acidic scrubbing liquid.

2. The method of claim 1 , comprising recycling all or part of the scrubbing liquid utilized in the off-gas treatment section to the urea ammonium nitrate section.

3. The method of claim 1 , comprising sending all or part of the scrubbing liquid utilized in the off-gas treatment section directly to the aqueous solution of urea ammonium nitrate.

4. The method of claim 2 , wherein in addition a Diesel Exhaust Fluid (DEF) product is prepared, the method comprising dividing a stream of urea liquid of the urea production unit having the finishing section into at least two streams, adding an additive to one of said streams downstream of said dividing, and preparing a DEF product from the other stream, and wherein the stream with said additive is subjected to solidification in the finishing section.

5. The method of claim 1 , wherein also the ammonia containing off-gas from the urea production unit and/or the urea ammonium nitrate section is sent to a gas inlet of the off-gas treatment section.

6. The method of claim 1 , wherein ammonia-containing off-gas of the finishing section is subjected to scrubbing to remove droplets and particles and subsequently to scrubbing with acidic scrubbing liquid in said off-gas treatment section.

7. The method of claim 1 , the method further comprising producing Calcium Ammonium Nitrate (CAN) granules by
(f) subjecting a part of the aqueous ammonium nitrate solution of step (c) and a calcium salt stream, to a CAN finishing unit so as to form CAN-granules and a CAN off-gas, said CAN off-gas containing ammonia, ammonium nitrate and entrained Ca-containing particles;
(g) feeding said CAN off-gas to the off-gas treatment section
wherein said off-gas treatment section is adapted to treat said CAN off-gas with an acidic scrubbing liquid thereby forming a Ca-containing salt solution before recycling the scrubbing liquid to the UAN section.

8. A system for the production of at least urea and urea ammonium nitrate comprising:
(a) a urea production unit comprising a urea finishing section, wherein the urea finishing section has a gas outlet for ammonia-containing off-gas,
(b) an ammonium nitrate section for producing ammonium nitrate in fluid communication with a source of nitric acid and a source of ammonia, having an outlet for aqueous ammonium nitrate solution and an outlet for off-gas, and a condensation section in fluid communication with said outlet for off-gas, for condensing at least part of said off-gas to form an acidic condensate,
(c) a urea ammonium nitrate section comprising a unit having an inlet in fluid connection with said outlet for aqueous ammonium nitrate solution and an inlet for receiving urea liquid, for combining said ammonium nitrate solution and said urea liquid, and having an outlet for urea ammonium nitrate solution, and
(d) an off-gas treatment section downstream of a urea finishing section, having a gas inlet in fluid connection with said gas outlet for off-gas of said urea finishing section, adapted to subject ammonia-containing off-gas of the urea finishing section to treatment with an acidic scrubbing liquid,
wherein said off-gas treatment section comprises an inlet in fluid communication with said condensation section for receiving said acidic condensate.

9. The system of claim 8 , wherein said inlet for receiving urea liquid of said urea ammonium nitrate section is in fluid connection with said urea production unit comprising a finishing section
wherein said urea production unit comprises a high pressure urea synthesis section comprising a high pressure stripper and a carbamate condenser and a urea reactor, or an integrated carbamate condenser and a urea reactor, wherein said urea production unit further comprises a recovery section and an evaporation section, and wherein said ammonium nitrate section comprises an inlet in fluid communication for off-gas with one or more of said high pressure synthesis section, recovery section and evaporation section.

10. The system of claim 8 , wherein said off-gas treatment section comprises an outlet for a liquid stream in fluid communication with a point downstream of said outlet for aqueous ammonium nitrate solution.

11. The system of claim 10 , which is adapted for the production of a DEF product, wherein the urea production unit comprises a divider for dividing a stream of urea liquid in at least two streams, and a unit for adding an additive to one of said streams downstream of said divider and upstream of a finishing section, and a unit for preparing a DEF product from the other stream.

12. The system of claim 8 , wherein said off-gas treatment section comprises a venturi scrubber.

13. The system of claim 8 , comprising a calcium ammonium nitrate (CAN) production section, said CAN production section comprising an inlet for ammonium nitrate in fluid communication with an outlet for ammonium nitrate from the ammonium nitrate section, wherein the CAN production section comprises a granulation section having an outlet for off-gas in fluid communication with a gas inlet of the off-gas treatment section.

14. The method of claim 4 , wherein the additive is formaldehyde.

15. The system of claim 12 , wherein said off-gas treatment section comprises a micro-mist venturi (MMV) scrubber.

16. The system of claim 8 which is adapted to perform a method comprising
(a) subjecting ammonia and carbon dioxide to urea forming conditions so as to obtain an aqueous urea solution,
(b) purifying the aqueous urea solution in a recovery section to remove residual ammonium carbamate so as to form a purified aqueous urea solution, and optionally subjecting at least part of the purified aqueous urea solution to evaporation so as to form concentrated urea liquid,
(c) subjecting ammonia and nitric acid to ammonium nitrate forming conditions so as to form an aqueous ammonium nitrate solution;
(d) combining said aqueous ammonium nitrate solution and at least a part of the purified aqueous urea solution and/or concentrated urea liquid in a urea ammonium nitrate section so as to obtai

Assignees

• Stamicarbon

Inventors

• Puci Giusy Elisa
• Dobree Joey

Classifications

• C01C1/185

  Preparation · CPC title

• C07C273/16

  Separation; Purification · CPC title

• B01D2257/406

  Ammonia · CPC title

• C05C1/00

  Ammonium nitrate fertilisers · CPC title

• B01D53/1493

  Selection of liquid materials for use as absorbents · CPC title