Removing hydrogen sulfide from a gaseous mixture using ferric ions bonded to calcined diatomite

• US 6,500,237 B2
• Filed: 02/07/2001
• Issued: 12/31/2002
• Est. Priority Date: 08/12/1997
• Status: Expired due to Term

• Current Assignee: Evoqua Water Technologies Canada Ltd. (Xylem, Inc.)
• Original Assignee: ADI International, Inc. (ADI Group Inc.)
• Inventors: McMullin, Michael J., Winchester, Eric L., Hum, Jeffrey K.
• Primary Examiner(s): CINTINS, IVARS C
• Application Number:
  US09/777,840
• Publication Number:
  US 20010005981A1
• Time in Patent Office: 692 Days
• Field of Search: 951/36, 951/48, 951/17, 951/21, 951/22, 423/231
• US Class Current: 95/117
• CPC Class Codes: B01J 20/0229 Compounds of Fe
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28097 being coated, filled or plugged with specific compounds
• CPC Class Codes: B01J 20/3078 Thermal treatment, e.g. calcining or pyrolizing
• CPC Class Codes: B01J 20/3092 Packing of a container, e.g. packing a cartridge or column of chromatography columns B01D15/206
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3217 Resulting in a chemical bond between the coating or impregnating layer and the carrier, support or substrate, e.g. a covalent bond
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/3433 of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• CPC Class Codes: B01J 20/3458 in the gas phase
• CPC Class Codes: B01J 2220/42 Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: B01J 2220/58 Use in a single column
• CPC Class Codes: C02F 1/281 using inorganic sorbents
• CPC Class Codes: C02F 2101/00 Nature of the contaminant
• CPC Class Codes: C02F 2101/103 Arsenic compounds
• CPC Class Codes: C02F 2101/20 Heavy metals or heavy metal compounds

Abstract

A process for removing hydrogen sulfide from a gas stream wherein the filtering media consists essentially of calcined diatomite and between 5% and 30% by weight of ferric ions bonded to the calcined diatomite. This process is particularly efficient due to the fact that the removal of hydrogen sulfide from the gas stream is effected with a single pass adsorption performance of up to 45 mg of H₂S per gram of filtering media. Other advantages include the fact that the process has the ability to remove H₂S form a gaseous mixture, from a concentration of 30,000 ppm down to non-detectable levels in a single pass. Repeated in-situ regeneration of the filtering media has been proven to be a simple matter of blowing ambient air through the filtering media.

Claims

1. A process for removing hydrogen sulfide from a gas stream, comprising the step of passing said gas stream through a filtering media consisting essentially of calcined diatomite and between 5% and 30% by weight of ferric ions bonded to said calcined diatomite.

2. The process as claimed in claim 1, wherein said step of passing said gas stream through said filtering media is effected at a velocity of 5 ft/min.

3. The process as claimed in claim 2 wherein said step of passing said gas stream through said filtering media is effected at a retention time of said gas stream through said filtering media of about 60 seconds.

4. The process as claimed in claim 2, further comprising the step of increasing a moisture content of said filtering media while maintaining said velocity.

5. The process as claimed in claim 1, wherein said step of passing said gas stream through said filtering media further comprises the step of reducing a hydrogen sulfide content in said gas stream from 30,000 ppm to a non-detectable level.

6. The process as claimed in claim 1, wherein said step of passing said gas stream through said filtering media further comprises the steps of passing said gas stream once through said filtering media and simultaneously adsorbing 45 mg of hydrogen sulfide from said gas stream for each gram of said filtering media.

7. The process as claimed in claim 1, further comprising the step of renewing said filtering media when said filtering media is saturated with sulfides by blowing ambient air through said filtering media.

8. The process as claimed in claim 7, farther comprising the step of repeating said steps of passing said gas stream through said filtering media and of renewing said filtering media, while maintaining an average hydrogen sulfide adsorption performance of said filtering media of 32 mg of hydrogen sulfide per gram of said filtering media.

9. The process as claimed in claim 8, wherein said steps of passing said gas stream through said filtering media and of renewing said filtering media are repeated 18 times while maintaining an average hydrogen sulfide adsorption performance of said filtering media of 32 mg of hydrogen sulfide per gram of said filtering media.

10. The process as claimed in claim 7, further comprising the step of enclosing said filtering media in a filtering column having a sight glass.

11. The process as claimed in claim 10, further comprising the step of visually monitoring a color change in said filtering media.

12. The process as claimed in claim 7, further comprising the steps of enclosing said filtering media in a filtering column, and carrying said step of renewing said filtering media in-situ within said filtering column.

13. The process as claimed in claim 1 further comprising the step of injecting air in said gas stream.

14. The process as claimed in claim 1 further comprising the step of causing said filtering media to have a pH of about 10.

15. A process for removing hydrogen sulfide from a gas stream, comprising the steps of;

passing said gas stream through a filtering media consisting essentially of;

calcined diatomite, and

between 5% and 30% by weight of ferric ions bonded by chemisorption bonds to said calcined diatomite, and

renewing said filtering media when said filtering media is saturated with sulfides by blowing air through said filtering media;

repeating said steps of passing said gas stream through said filtering media and of renewing said filtering media, while maintaining an average hydrogen sulfide adsorption performance of said filtering media of 32 mg of hydrogen sulfide per gram of said filtering media.

16. The process as claimed in claim 15, wherein said steps of passing said gas stream through said filtering media and of renewing said filtering media are repeated several times while maintaining an average hydrogen sulfide adsorption performance of said filtering media of 32 mg of hydrogen sulfide per gram of said filtering media.

17. The process as claimed in claim 15, wherein said steps of passing said gas stream through said filtering media and of renewing said filtering media are repeated 18 times while maintaining an average hydrogen sulfide adsorption performance of said filtering media of 32 mg of hydrogen sulfide per gram of said filtering media.

18. A process for removing hydrogen sulfide from a gas stream, comprising the step of passing said gas stream through a filtering media consisting essentially of calcined diatomite having particles ranging in sizes between about 30 mesh and about 60 mesh, and between 5% and 30% by weight of ferric ions bonded thereto by chemisorption bonds.

19. The process as claimed in claim 18, wherein said gas stream is moist, and said step of passing said gas stream through a filtering media comprises the steps of simultaneously adsorbing moisture from said gas stream in said filtering media and maintaining particle sizes in said filtering media between about 30 mesh and 60 mesh.

20. The process as claimed in claim 18, further comprising the steps of regenerating said filtering media by passing ambient air through said filtering media, and repeating said steps of passing said gas stream through said filtering media and regenerating said filtering media until a cumulative hydrogen sulfide removal capacity of said filtering media has reached about one half the weight of said filtering media, while maintaining a single-pass hydrogen sulfide removal performance of said filtering media of 32 mg per gram of said filtering media.

21. A process for removing hydrogen sulfide from an anaerobic process gas stream, comprising the step of passing said gas stream through a filtering media consisting essentially of calcined diatomite and between 5% and 30% by weight of ferric ions bonded to said calcined diatomite.