Method for achieving ultra-low emission limits in VOC control

• US 20050211090A1
• Filed: 08/25/2003
• Published: 09/29/2005
• Est. Priority Date: 08/25/2003
• Status: Abandoned Application

• Current Assignee: Matthew Lee Mccullough
• Original Assignee: Matthew Lee Mccullough
• Inventors: McCullough, Matthew Lee
• Application Number:
  US10/649,016
• Publication Number:
  US 20050211090A1
• Time in Patent Office: Days
• US Class Current: 95/92
• CPC Class Codes: B01D 2253/202 Polymeric adsorbents
• CPC Class Codes: B01D 2253/25 Coated, impregnated or composite adsorbents
• CPC Class Codes: B01D 2257/206 Organic halogen compounds
• CPC Class Codes: B01D 2257/2064 Chlorine
• CPC Class Codes: B01D 2257/708 Volatile organic compounds V.O.C.'s
• CPC Class Codes: B01D 2257/93 Toxic compounds not provided for in groups B01D2257/00 - B01D2257/708
• CPC Class Codes: B01D 2258/06 Polluted air
• CPC Class Codes: B01D 2259/40007 Controlling pressure or temperature swing adsorption
• CPC Class Codes: B01D 2259/40056 Gases other than recycled product or process gas
• CPC Class Codes: B01D 2259/40081 Counter-current
• CPC Class Codes: B01D 2259/4009 using hot gas
• CPC Class Codes: B01D 2259/40094 by applying microwaves
• CPC Class Codes: B01D 2259/40096 by using electrical resistance heating
• CPC Class Codes: B01D 2259/4061 using five beds
• CPC Class Codes: B01D 2259/804 UV light
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/08 according to the "moving bed" method
• CPC Class Codes: B01D 53/10 with dispersed adsorbents
• CPC Class Codes: B01D 53/12 according to the "fluidised technique"
• CPC Class Codes: B01D 53/8662 Organic halogen compounds
• CPC Class Codes: B01D 53/8668 : Removing organic compounds not provided for in B01D53/8603 - B01D53/8665
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The present invention relates to adsorption and regeneration of adsorbent media for air pollution control, volatile organic compound (VOC) control, hazardous air pollutant (HAP) control, toxic air contaminant (TAC) control, and solvent recovery. The present invention is an improved device for removing VOCs/HAPs/TACs from high volume air streams to ultra-low levels using synthetic polymeric adsorbents. The invention is embodied in a HAP adsorption section, a regeneration section, and a chemical destruction or recovery section. In order to recover HAPs from low concentration air streams, multiple adsorption (concentration) steps may be necessary. Adsorption is typically accomplished with a multi-tray fluidized bed operating in the moving bed to fully fluidized regime. The regeneration section has either a long, multi-stage regeneration column with a high number of stages relative to the number of theoretical desorption stages required or a recirculating fluidized bed with a high make-up air to volume ratio. Destruction can be carried out through a thermal or catalytic oxidizer or the regeneration air stream can be concentrated into fixed-bed carbon vessels.

Claims

1. A process for treating HAPs in air to ultra-low emission limits, said process to include the steps of:

a. Passing the air stream through a bed of synthetic adsorbent,

b. Removing the adsorbent to a regeneration column;

c. Regenerating the adsorbent at elevated temperature and above-atmospheric pressure in a highly turbulent fluidized bed operating as an equilibrium-stage column;

d. Cooling of the adsorbent;

e. Placement of the adsorbent back into the adsorption bed;

f. Destruction of the HAP vapors using a catalytic oxidizer,

g. Scrubbing of the vapors with a caustic scrubber or solid basic adsorbent to remove acid gas; and

h. Exhausting the regeneration air stream to the atmosphere.

2. A process according to claim 1, wherein the adsorbent is also hydrophobic.

3. A process according to claim 1, wherein the HAP vapors are destroyed in a thermal oxidizer.

4. A process according to claim 1, wherein the HAP vapors are destroyed in a UV/Oxidation system.

5. A process according to claim 1, wherein the scrubbed vapors are exhausted into the adsorption bed to remove combustion by-products.

6. A process according to claim 1, wherein the regeneration column is placed under vacuum to reduce the temperature required for regeneration.

7. A process according to claim 1, wherein heat recovery is used to minimize operating costs.

8. A process according to claim 1, wherein the inlet air stream is cooled to maximize adsorption of HAPs or low-boiling point compounds.

9. A process according to claim 1, wherein the desorbed HAP vapors are adsorbed onto another adsorbent bed.

10. A process according to claim 1, wherein the adsorption bed and regeneration bed are the same device.

11. A process according to claim 1, wherein the HAP vapors are recovered in liquid or gaseous form for recycling, reuse, or off-site disposal.

12. A process according to claim 1, wherein the regeneration column is heated with a microwave generator,

13. Any combination of claims 1 through 12.

14. A process for treating HAPs in air to ultra-low emission limits, said process to include the steps of:

a. Passing the air stream through a bed of synthetic adsorbent,

b. Removing the adsorbent to a regeneration column;

c. Regenerating the adsorbent at elevated temperature and above-atmospheric pressure in a highly turbulent fluidized bed operating as an equilibrium-stage column;

d. Utilizing an inert gas or a gas with decreased oxygen levels to effect the regeneration to allow for higher temperature in the regeneration column and/or to effect regeneration of higher boiling point compounds without oxidizing the adsorbent,

e. Cooling of the adsorbent;

f. Placement of the adsorbent back into the adsorption bed;

g. Cooling of the desorbed HAP vapors;

h. Adsorption of the HAP vapors using an adsorbent bed; and

i. Exhausting the regeneration air stream to the atmosphere.

15. A process according to claim 14, wherein the adsorbent is also hydrophobic.

16. A process according to claim 14, wherein oxygen content of the regeneration gas is monitored and/or controlled to allow for higher temperature in the regeneration column and/or to effect regeneration of higher boiling point compounds without oxidizing the adsorbent;

17. A process according to claim 14, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a catalytic oxidizer and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

18. A process according to claim 14, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a thermal oxidizer and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

19. A process according to claim 14, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a UV/Oxidation system and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

20. A process according to claim 14, wherein the HAP vapors are destroyed in a UV/Oxidation system.

21. A process according to claim 14, wherein the scrubbed vapors are exhausted into the adsorption bed to remove combustion by-products.

22. A process according to claim 14, wherein the regeneration column is placed under vacuum to reduce the temperature required for regeneration.

23. A process according to claim 14, wherein heat recovery is used to minimize operating costs.

24. A process according to claim 14, wherein the inlet air stream is cooled to maximize adsorption of HAPs or low-boiling point compounds.

25. A process according to claim 14, wherein the adsorption bed and regeneration bed are the same device.

26. A process according to claim 14, wherein the HAP vapors are recovered in liquid or gaseous form for recycling, reuse, or off-site disposal;

27. A process according to claim 14, wherein the regeneration column is heated with a microwave generator.

28. Any combination of claims 14 through 27.

29. A process for treating HAPs in air to ultra-low emission limits, said process to include the steps of:

a. Passing the air stream through a bed of synthetic adsorbent;

b. Removing the adsorbent to a regeneration bed;

c. Regenerating the adsorbent at elevated temperature and above-atmospheric pressure in a highly turbulent recirculating fluidized bed;

d. Cooling of the adsorbent;

e. Placement of the adsorbent back into the adsorption bed;

f. Destruction of the HAP vapors using a catalytic oxidizer,

g. Scrubbing of the vapors with a caustic scrubber or solid basic adsorbent to remove acid gas; and

h. Exhausting the regeneration air stream to the atmosphere.

30. A process according to claim 29, wherein the adsorbent is also hydrophobic.

31. A process according to claim 29, wherein the HAP vapors are destroyed in a thermal oxidizer.

32. A process according to claim 29, wherein the HAP vapors are destroyed in a UV/Oxidation system.

33. A process according to claim 29, wherein the scrubbed vapors are exhausted into the adsorption bed to remove combustion by-products.

34. A process according to claim 29, wherein the regeneration bed is placed under vacuum to reduce the temperature required for regeneration.

35. A process according to claim 29, wherein heat recovery is used to minimize operating costs.

36. A process according to claim 29, wherein the inlet air stream is cooled to maximize adsorption of HAPs or low-boiling point compounds.

37. A process according to claim 29, wherein the desorbed HAP vapors are adsorbed onto another adsorbent bed.

38. A process according to claim 29, wherein the adsorption bed and regeneration bed are the same device.

39. A process according to claim 29, wherein the HAP vapors are recovered in liquid or gaseous form for recycling, reuse, or off-site disposal;

40. A process according to claim 29, wherein the regeneration column is heated with a microwave generator.

41. Any combination of claims 29 through 40.

42. A process for treating HAPs in air to ultra-low emission limits, said process to include the steps of:

a. Passing the air stream through a bed of synthetic adsorbent;

b. Removing the adsorbent to a regeneration bed;

c. Regenerating the adsorbent at elevated temperature and above-atmospheric pressure in a highly turbulent recirculating fluidized bed;

d. Utilizing an inert gas or a gas with decreased oxygen levels to effect the regeneration to allow for higher temperature in the regeneration column and/or to effect regeneration of higher boiling point compounds without oxidizing the adsorbent;

e. Cooling of the adsorbent;

f. Placement of the adsorbent back into the adsorption bed;

g. Cooling of the desorbed HAP vapors;

h. Adsorption of the HAP vapors using an adsorbent bed; and

i. Exhausting the regeneration air stream to the atmosphere.

43. A process according to claim 42, wherein the adsorbent is also hydrophobic.

44. A process according to claim 42, wherein oxygen content of the regeneration gas is monitored and/or controlled to allow for higher temperature in the regeneration column and/or to effect regeneration of higher boiling point compounds without oxidizing the adsorbent;

45. A process according to claim 42, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a catalytic oxidizer and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

46. A process according to claim 42, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a thermal oxidizer and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

47. A process according to claim 42, wherein oxygen is reintroduced in the HAP vapor stream and the vapors are destroyed in a UV/Oxidation system and the vapors are scrubbed using a caustic scrubber or solid basic adsorbent.

48. A process according to claim 42, wherein the HAP vapors are destroyed in a UV/Oxidation system.

49. A process according to claim 42, wherein the scrubbed vapors are exhausted into the adsorption bed to remove combustion by-products.

50. A process according to claim 42, wherein the regeneration column is placed under vacuum to reduce the temperature required for regeneration.

51. A process according to claim 42, wherein heat recovery is used to minimize operating costs.

52. A process according to claim 42, wherein the inlet air stream is cooled to maximize adsorption of HAPs or low-boiling point compounds.

53. A process according to claim 42, wherein the adsorption bed and regeneration bed are the same device.

54. A process according to claim 42, wherein the HAP vapors are recovered in liquid or gaseous form for recycling, reuse, or off-site disposal;

55. A process according to claim 42, wherein the regeneration column is heated with a microwave generator.

56. Any combination of claims 42 through 55.