Process for ammonia recovery

• US 7,537,744 B2
• Filed: 04/02/2002
• Issued: 05/26/2009
• Est. Priority Date: 04/06/2001
• Status: Expired due to Term

• Current Assignee: Rohm and Haas Company (Dow, Inc.)
• Original Assignee: Rohm and Haas Company (Dow, Inc.)
• Inventors: Benderly, Abraham, Myers, Ronald Eugene, DeCourcy, Michael Stanley, Briegel, Keith Frederick
• Primary Examiner(s): Langel; Wayne
• Application Number:
  US10/114,224
• Publication Number:
  US 20020146363A1
• Time in Patent Office: 2,611 Days
• Field of Search: 423/238, 423/352, 422/240, 422/241, 952/43, 952/45, 952/51, 952/63, 961/55, 962/02
• US Class Current: 423/238
• CPC Class Codes: B01D 3/322 Reboiler specifications
• CPC Class Codes: B01D 3/343 the substance being a gas
• CPC Class Codes: B01D 53/18 Absorbing units; Liquid distributors therefor B01D3/16, B01D3/26, B01D3/30 take precedence; packing elements B01J19/30, B01J19/32
• CPC Class Codes: B01J 19/02 Apparatus characterised by being constructed of material selected for its chemically-resistant properties
• CPC Class Codes: B01J 2219/00006 Large-scale industrial plants
• CPC Class Codes: B01J 2219/00087 with heat exchange elements outside the reactor
• CPC Class Codes: B01J 2219/00101 Reflux columns
• CPC Class Codes: B01J 2219/00105 part or all of the reactants being heated or cooled outside the reactor while recycling
• CPC Class Codes: B01J 2219/0209 of glass
• CPC Class Codes: B01J 2219/0236 Metal based
• CPC Class Codes: B01J 2219/0245 of synthetic organic material
• CPC Class Codes: B01J 2219/0277 Metal based
• CPC Class Codes: B01J 2219/0286 Steel
• CPC Class Codes: B01J 2219/029 Non-ferrous metals
• CPC Class Codes: C01C 1/12 Separation of ammonia from gases and vapours as part of the ammonia synthesis process C01C1/04

Abstract

An improved process for ammonia recovery is provided for the recovery of substantially pure ammonia for use in industrial processes. In this improved method, specific raw materials and/or specific materials of construction are used. Overall efficiency and operational cost savings are increased as a result of the process of the present invention.

Claims

1. An ammonia recovery process, the process comprising the steps of:

a) providing an ammonia containing process stream;

b) providing a capture solution comprising one or more selected from the group consisting of;

phosphoric acid, nitric acid, oxalic acid, boric acid, and ammonium hydrogen phosphate;

c) quenching the ammonia containing process stream to form an ammoniated capture solution;

d) purifying the ammoniated capture solution to form a purified ammoniated capture solution;

e) freeing ammonia from the purified ammoniated capture solution to form a concentrated ammonia product stream;

wherein the concentration of Nickel ions in the capture solution is maintained at a concentration of less than 250 ppm.

2. The process of claim 1 wherein the ammonia containing process stream further comprises hydrogen cyanide.

3. The process of claim 1 wherein the ammoniated capture solution comprises cyanide ions.

4. The process of claim 1 wherein the concentration of nickel in the capture solution, as measured at its point of introduction into the ammonia recovery process, is less than 250 ppm nickel ions.

5. The process of claim 1 wherein the freeing is performed in a dissociation column.

6. An ammonia recovery process, the process comprising the steps of:

a) providing an ammonia containing process stream;

b) providing a capture solution comprising one or more selected from the group consisting of;

phosphoric acid, nitric acid, oxalic acid, boric acid, and ammonium hydrogen phosphate;

c) quenching the ammonia containing process stream to form an ammoniated capture solution;

d) purifying the ammoniated capture solution to form a purified ammoniated capture solution;

e) freeing ammonia from the purified ammoniated capture solution to form a concentrated ammonia product stream;

wherein the concentration of Nickel ions in the capture solution is maintained at a concentration of less than 250 ppm wherein the freeing is performed in a dissociation column and further wherein the dissociation column comprises materials of construction having less than 20% Nickel by weight.

7. An ammonia recovery process, the process comprising the steps of:

a) providing an ammonia containing process stream;

b) providing a capture solution comprising one or more selected from the group consisting of;

phosphoric acid, nitric acid, oxalic acid, boric acid, and ammonium hydrogen phosphate;

c) quenching the ammonia containing process stream to form an ammoniated capture solution;

d) purifying the ammoniated capture solution to form a purified ammoniated capture solution;

e) freeing ammonia from the purified ammoniated capture solution to form a concentrated ammonia product stream;

wherein the concentration of Nickel ions in the capture solution is maintained at a concentration of less than 250 ppm; and

wherein the freeing is performed in a dissociation column and further wherein the dissociation column comprises one or more low-nickel content materials selected from the group consisting of;

glass, epoxy, elastomer, fluoropolymer, 300 series stainless steels, 400 series steels, duplex stainless steels, tantalum, and zirconium.