METHODS AND APPARATUSES TO REDUCE HYDROGEN SULFIDE IN A BIOGAS

• US 20110042307A1
• Filed: 04/22/2010
• Published: 02/24/2011
• Est. Priority Date: 04/23/2009
• Status: Abandoned Application

• Current Assignee: DVO, Inc.
• Original Assignee: GHD, Inc.
• Inventors: Dvorak, Stephen W., VanOrnum, Douglas
• Application Number:
  US12/765,301
• Publication Number:
  US 20110042307A1
• Time in Patent Office: Days
• US Class Current: 210/603
• CPC Class Codes: B01D 2251/102 Oxygen
• CPC Class Codes: B01D 2256/24 Hydrocarbons
• CPC Class Codes: B01D 2258/05 Biogas
• CPC Class Codes: B01D 53/346 Controlling the process
• CPC Class Codes: B01D 53/52 Hydrogen sulfide
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: C12M 21/04 for producing gas, e.g. biogas digesters for manure with production of biogas A01C3/028, biological treatment of water, waste water or sewage C02F3/00, C02F11/02, preparation of natural gas or syngas C10L3/06, C10L3/10
• CPC Class Codes: C12M 23/36 Means for collection or storage of gas; Gas holders
• CPC Class Codes: C12M 29/24 Recirculation of gas
• CPC Class Codes: C12M 47/18 Gas cleaning, e.g. scrubbers; Separation of different gases separating dispersed particles from gases or vapours B01D45/00; separation of gases or vapours B01D53/00; gas washing apparatus for laboratory uses B01L5/04
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

Apparatuses and methods for anaerobic digestion of high-solids waste and the removal of hydrogen sulfide from a biogas are provided. The methods may include and the apparatuses may be used for moving the solid waste in a corkscrew-like fashion through a closed container. The method may further include moving the high-solids waste into contact with a heating device to facilitate the corkscrew-like movement. Other methods and apparatuses may use at least one of a partition and a conduit from which liquid or gas is discharged. The invention also relates to methods and apparatuses for reducing the amount of H₂S in a biogas produced from an anaerobic digester.

Claims

1. A method for reducing hydrogen sulfide in a biogas comprising

passing biogas through a low pressure inlet of a positive displacement device, wherein the positive displacement device also comprises a high pressure outlet;

passing the biogas from the low pressure inlet into an apparatus located between the low pressure and high pressure sides of the positive displacement device, wherein a gas eductor is coupled to said apparatus,

adding air through the gas eductor to the biogas;

compressing the biogas; and

passing the compressed biogas through the high pressure outlet to the digester vessel.

2. The method of claim 1, wherein said positive displacement device is a root'"'"'s blower.

3. The method of claim 1, wherein said adding air is regulated through a mass flow controller.

4. The method of claim 3, further comprising measuring the amount of biogas produced by said anaerobic digestor.

5. The method of claim 4, wherein said measuring an amount of biogas is accomplished through a mass flow sensor.

6. The method of claim 5, wherein said mass flow sensor communicates with the mass flow controller to adjust the amount of air.

7. The method of claim 1, wherein a constant ratio of biogas to air is maintained.

8. The method of claim 1 further comprising returning said biogas to an anaerobic digestor.

9. The method of claim 8, wherein returning said biogas comprises injecting the biogas near the floor of the digester.

10. The method of claim 9, wherein the injected biogas increases the rapidity of a corkscrew like flow path for heated sludge in the anaerobic digestor.

11. A method for reducing hydrogen sulfide in a biogas comprising

passing biogas through a low pressure inlet of a positive displacement device, wherein the positive displacement device also comprises a high pressure outlet;

passing the biogas from the low pressure inlet into an apparatus located between the low pressure and high pressure sides of the positive displacement device, wherein a gas eductor is coupled to said apparatus,

measuring an amount of biogas produced by the digester, wherein the measurement is accomplished by a mass flow sensor;

adding a regulated amount of air through the gas eductor to the biogas, wherein the regulation is accomplished by a mass flow controller that communicates with the mass flow sensor;

compressing the biogas; and

passing the compressed biogas from the high pressure outlet to the digester vessel.

12. The method of claim 11 further comprising injecting the biogas near the floor of the digester.

13. The method of claim 11 further comprising increasing the flow of heated sludge in a corkscrew like flow path in the digester.

14. The method of claim 11, wherein adding a regulated amount of air comprises maintaining a ratio of biogas to air of 20:

1.

15. An apparatus for reducing hydrogen sulfide in a biogas comprising:

a positive displacement device with a low pressure inlet and a high pressure outlet;

an apparatus with a first port, which is coupled to the low pressure inlet, a second port, which is coupled to the high pressure outlet, and a third port;

a gas eductor that is coupled to the third port of the apparatus;

a mass flow controller coupled to the gas eductor; and

a mass flow sensor that measures the amount of biogas produced by the digester and communicates with the mass flow controller.

16. The apparatus of claim 15, wherein the positive displacement device is a root'"'"'s blower.

17. The apparatus of claim 15, wherein the gas eductor pulls in air.

18. The apparatus of claim 17, wherein the mass flow controller and mass flow sensor communicate to establish a constant ratio of biogas to air.

19. The apparatus of claim 17, wherein the apparatus further comprises an air filter coupled to the gas eductor.

20. The apparatus of claim 18, wherein the ratio of biogas to air is 20:

1.