Systems and methods for nitrogen recovery from a gas stream

• US 10,239,016 B2
• Filed: 12/05/2017
• Issued: 03/26/2019
• Est. Priority Date: 12/07/2016
• Status: Active Grant

• Current Assignee: NuOrganics LLC
• Original Assignee: NuOrganics LLC
• Inventors: Giraldo, Eugenio, Wingler, Barbara Jean
• Primary Examiner(s): Vanoy, Timothy C
• Application Number:
  US15/832,213
• Publication Number:
  US 20180154306A1
• Time in Patent Office: 476 Days
• CPC Class Codes: B01D 2251/10 Oxidants
• CPC Class Codes: B01D 2251/306 of potassium
• CPC Class Codes: B01D 2251/508 Sulfur dioxide
• CPC Class Codes: B01D 2252/10 Inorganic absorbents
• CPC Class Codes: B01D 2255/70 Non-metallic catalysts, additives or dopants
• CPC Class Codes: B01D 2258/0266 from animal farms
• CPC Class Codes: B01D 2258/05 Biogas
• 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: B01D 53/263 by absorption
• CPC Class Codes: B01D 53/346 Controlling the process
• CPC Class Codes: B01D 53/56 Nitrogen oxides B01D53/60 takes precedence
• CPC Class Codes: B01D 53/58 Ammonia
• CPC Class Codes: B01D 53/78 with gas-liquid contact
• CPC Class Codes: B01D 53/79 Injecting reactants

Abstract

Methods of producing a treated gas by removing nitrogenous compounds are disclosed. Methods of recovering ammonia from a gas stream having nitrogenous compounds are disclosed. Methods of producing a fertilizer product from organic waste are disclosed. The methods may include introducing aqueous sulfurous acid into a gas stream having nitrogenous compounds to absorb the nitrogenous compounds in a liquid and produce a treated gas. The methods may also include maintaining the pH of certain solutions above 5 or introducing an oxidant into certain solutions to produce sulfate ions. Systems for removing nitrogenous compounds including a reaction subsystem, a solids-liquid separator, a temperature control subsystem, an oxidation control subsystem, and a recirculation line are also disclosed. The systems may be employed to remove nitrogenous compounds from a gas stream, recover the ammonia from the gas stream, or produce a fertilizer product from the recovered ammonia.

Claims

1. A method of producing a treated gas by removing nitrogenous compounds from a gas stream, the method comprising:

introducing sulfur dioxide vapor into water to produce aqueous sulfurous acid;

introducing the aqueous sulfurous acid into a gas stream comprising nitrogenous compounds to produce ammonium ions, sulfurous acid ions, a nitrogenous liquid, and the treated gas; and

maintaining a pH of the aqueous sulfurous acid and the nitrogenous liquid above 5.

2. The method of claim 1, further comprising diluting the aqueous sulfurous acid with water.

3. The method of claim 1, further comprising maintaining a pH of the aqueous sulfurous acid and the nitrogenous liquid between about 5 and about 7.

4. The method of claim 1, further comprising drying organic material to produce the gas stream comprising nitrogenous compounds.

5. The method of claim 4, further comprising separating solids from the gas stream.

6. The method of claim 4, wherein the organic material comprises at least one of poultry manure, poultry litter, and sewage sludge.

7. The method of claim 1, further comprising burning elemental sulfur in the presence of oxygen to produce the sulfur dioxide vapor.

8. The method of claim 7, further comprising maintaining a temperature of the aqueous sulfurous acid and the nitrogenous liquid between about 15°

C. and about 80°

C.

9. The method of claim 1, wherein the treated gas comprises less than 1% nitrogen, sulfur, phosphate, and potassium.

10. A method of recovering ammonia from a gas stream, the method comprising:

introducing sulfur dioxide vapor into water to produce aqueous sulfurous acid;

introducing the aqueous sulfurous acid into a gas stream comprising nitrogenous compounds to produce ammonium ions, sulfurous acid ions, and a nitrogenous liquid;

introducing an oxidant into the aqueous sulfurous acid or the nitrogenous liquid to oxidize a predetermined amount of the sulfurous acid ions to sulfate ions; and

collecting the nitrogenous liquid comprising remaining sulfurous acid ions, the ammonium ions, and the sulfate ions.

11. The method of claim 10, wherein the predetermined amount of the sulfurous acid ions is between about 5% and about 50% of the sulfurous acid ions.

12. The method of claim 10, further comprising maintaining a concentration of total dissolved solids in the nitrogenous liquid below about 46%.

13. The method of claim 12, wherein the nitrogenous liquid comprises at least 8% nitrogen and at least 9% sulfur by mass.

14. The method of claim 12, wherein the nitrogenous liquid comprises less than 1% phosphate and potassium.

15. The method of claim 10, further comprising maintaining a concentration of total dissolved solids in the nitrogenous liquid above about 46%, whereby the sulfate ions and the ammonium ions precipitate to form ammonium sulfate crystals.

16. The method of claim 15, further comprising collecting the ammonium sulfate crystals.

17. The method of claim 10, further comprising maintaining a pH of the aqueous sulfurous acid and the nitrogenous liquid between about 2 and about 9.

18. The method of claim 17, further comprising maintaining a pH of the aqueous sulfurous acid and the nitrogenous liquid between about 5 and about 7.

19. The method of claim 10, further comprising dosing the aqueous sulfurous acid or the nitrogenous liquid with a biological catalyst.

20. The method of claim 10, further comprising drying organic material to produce the gas stream comprising nitrogenous compounds.

21. The method of claim 20, further comprising separating solids from the gas stream.

22. The method of claim 20, wherein the organic material comprises at least one of poultry manure, poultry litter, and sewage sludge.

23. The method of claim 10, further comprising burning elemental sulfur in the presence of oxygen to produce the sulfur dioxide vapor.

24. The method of claim 23, further comprising maintaining a temperature of the aqueous sulfurous acid and the nitrogenous liquid between about 15°

C. and about 80°

C.

25. A system for removing nitrogenous compounds from a gas stream, the system comprising:

a source of sulfur dioxide vapor;

a source of a gas stream comprising nitrogenous compounds;

a source of water;

a source of an oxidant;

a reaction subsystem comprising at least one absorption chamber, a treated gas outlet, and a product outlet, the reaction subsystem fluidly connected to the source of the sulfur dioxide vapor, the source of the gas stream, the source of the water, and the source of the oxidant, and constructed and arranged to combine the sulfur dioxide vapor, the gas stream, the water, and the oxidant;

a solids-liquid separator fluidly connected downstream of the reaction subsystem through the product outlet, the solids-liquid separator comprising a solid product outlet and liquid product outlet;

a temperature control subsystem configured to maintain a predetermined temperature range within the reaction subsystem;

an oxidation control subsystem configured to maintain a predetermined oxidation reduction potential (ORP) within the reaction subsystem; and

a recirculation line extending between the at least one absorption chamber and a recycle inlet of the reaction subsystem, the recirculation line constructed and arranged to reintroduce water vapor and residual gases not absorbed in the at least one absorption chamber to the reaction subsystem.

26. The system of claim 25, wherein the temperature control subsystem comprises a temperature sensor.

27. The system of claim 26, wherein the temperature control subsystem comprises a control module electrically connected to the temperature sensor and configured to adjust a temperature within the reaction subsystem responsive to a measurement obtained by the temperature sensor.

28. The system of claim 25, wherein the temperature control subsystem comprises a heat exchanger constructed and arranged to transfer heat between the reaction subsystem and one or more of the source of the sulfur dioxide vapor, the source of the gas stream, and the source of the water.

29. The system of claim 25, wherein the predetermined temperature range is between about 15°

C. and about 80°

C.

30. The system of claim 25, further comprising a pH meter configured to measure pH of a solution within the reaction subsystem.

31. The system of claim 30, further comprising a control module electrically connected to the pH meter and configured to adjust the pH within the reaction subsystem responsive to a measurement obtained by the pH meter.

32. The system of claim 31, wherein the control module is configured to maintain the pH above 5.

33. The system of claim 32, wherein the control module is configured to maintain the pH between about 5 and about 7.

34. The system of claim 25, further comprising an ORP sensor configured to measure ORP of a solution within the reaction subsystem.

35. The system of claim 34, further comprising a control module electrically connected to the ORP sensor and configured to adjust the ORP within the reaction subsystem responsive to a measurement obtained by the ORP sensor.

36. The system of claim 25, wherein the predetermined ORP is between about +400 mV and about +900 mV.

37. The system of claim 25, further comprising a conductivity meter configured to measure conductivity of a gas or solution within the reaction subsystem.

38. The system of claim 37, further comprising a control module electrically connected to the conductivity meter and configured to adjust the conductivity of the gas or the solution within the reaction subsystem responsive to a measurement obtained by the conductivity meter.

39. The system of claim 38, wherein the control module is configured to maintain a concentration of total dissolved solids in the solution within the reaction subsystem below about 46%.

40. The system of claim 38, wherein the control module is configured to maintain a concentration of total dissolved solids in the solution within the reaction subsystem above about 46%.

41. The system of claim 25, wherein the source of the sulfur dioxide vapor comprises a sulfur burner.

42. The system of claim 25, wherein the source of the gas stream comprises an organic material dryer and a solids-gas separator comprising a solids waste outlet and a gas stream outlet, and the source of the gas stream is fluidly connected to the reaction subsystem through the gas stream outlet of the solids-gas separator.

43. The system of claim 25, further comprising a wet electrostatic precipitator positioned within the at least one absorption chamber.

44. The system of claim 25, further comprising an evaporator fluidly connected downstream of the reaction subsystem through the product outlet and upstream of the solids-liquid separation unit.