Landfill gas extraction systems and methods

Patent metadata

Field	Value
Publication number	US-11273473-B2
Application number	US-202016901430-A
Country	US
Kind code	B2
Filing date	Jun 15, 2020
Priority date	Oct 1, 2018
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output. The control system comprises a controller configured to: obtain a value indicating measured energy content of landfill gas collected at the gas output from the plurality of wells; determine whether the measured energy content is different from a target energy content; and in response to determining that the measured energy content is different from the target energy content: control a plurality of valves disposed in the well piping to change flow rates of landfill gas being extracted from at least some of the plurality of wells at least in part by changing degrees to which the plurality of valves are open.

First claim

What is claimed is:

1. A method for controlling, with a control system comprising at least one controller, extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output, the plurality of wells comprising a first well having a first valve for controlling a flow rate of landfill gas being extracted from the first well, the method comprising:
using the at least one controller to perform:
determining, based on a measure of concentration of a first constituent gas in landfill gas collected from at least some of the plurality of wells, a global adjustment to be made to flow rates of landfill gas being extracted from the at least some of the plurality of wells, the at least some of the plurality of wells including the first well;
determining, based on a measure of concentration of a second constituent gas in landfill gas collected from the first well, a local adjustment to be made to the first valve to adjust the flow rate of landfill gas being extracted from the first well;
determining at least one adjustment to be applied to the first valve based at least in part on the global adjustment and the local adjustment; and
adjusting the flow rate of the first well by applying the at least one adjustment to the first valve of the first well.

2. The method of claim 1 , wherein the local adjustment comprises a value indicating a degree to which to open or close the first valve.

3. The method of claim 1 , wherein the global adjustment comprises a value indicating a degree to which to open or close the first valve.

4. The method of claim 3 , wherein the at least one adjustment consists of a single adjustment determined using the local adjustment and the global adjustment.

5. The method of claim 4 , wherein the single adjustment comprises a sum of the local adjustment and the global adjustment.

6. The method of claim 5 , wherein the single adjustment comprises a weighted sum of the local adjustment and the global adjustment.

7. The method of claim 1 , wherein the at least some of the plurality of wells includes a second well having a second valve for controlling a flow rate of landfill gas being extracted from the second well, the method further comprising:
determining, with the at least one controller, based on a measure of concentration of the second constituent gas in landfill gas collected from the second well, a local adjustment to be made to the second valve;
determining, with the at least one controller, at least one adjustment to be made to the second valve based at least in part on the global adjustment and/or the local adjustment to be made to the second valve; and
adjusting, with the at least one controller, the flow rate of the second well by applying the at least one adjustment to be made to the second valve to the second valve of the second well.

8. The method of claim 1 , wherein the first constituent gas comprises methane and the second constituent gas comprises one of methane, oxygen, or nitrogen.

9. The method of claim 8 , wherein determining the global adjustment is performed based on a measure of energy content of the landfill gas being extracted from the at least some of the plurality of wells.

10. A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output, the plurality of wells comprising a first well having a first valve for controlling a flow rate of landfill gas being extracted from the first well, the control system comprising:
at least one controller configured to:
determine, based on a measure of concentration of a first constituent gas in landfill gas collected from at least some of the plurality of wells, a global adjustment to be made to flow rates of landfill gas being extracted from at least some of the plurality of wells, the at least some of the plurality of wells including the first well;
determine, based on a measure of concentration of a second constituent gas in landfill gas collected from the first well, a local adjustment to be made to the first valve to adjust the flow rate of landfill gas being extracted from the first well;
determine at least one adjustment to be applied to the first valve based at least in part on the global adjustment and the local adjustment; and
adjust the flow rate of the first well by applying the at least one adjustment to the first valve of the first well.

11. The control system of claim 10 , wherein the local adjustment comprises a value indicating a degree to which to open or close the first valve.

12. The control system of claim 11 , wherein the global adjustment comprises a value indicating a degree to which to open or close the first valve.

13. The control system of claim 12 , wherein the at least one adjustment consists of a single adjustment determined using the local adjustment and the global adjustment.

14. The control system of claim 13 , wherein the single adjustment comprises a sum of the local adjustment and the global adjustment.

15. The control system of claim 14 , wherein the single adjustment comprises a weighted sum of the local adjustment and the global adjustment.

16. The control system of claim 10 wherein the at least some of the plurality of wells includes a second well having a second valve for controlling a flow rate of landfill gas being extracted from the second well and the at least one controller is further configured to:
determine, based on a measure of concentration of the second constituent gas in landfill gas collected from the second well, a local adjustment to be made to the second valve;
determine at least one adjustment to be applied to the second valve based at least in part on the global adjustment and/or the local adjustment to be made to the second valve; and
adjust the flow rate of the second well by applying the at least one adjustment to be made to the second valve to the second valve of the second well.

17. The control system of claim 10 , wherein the first constituent gas comprises methane and the second constituent gas comprises one of methane, oxygen, or nitrogen.

18. The control system of claim 17 , wherein the at least one controller is configured to determine the global adjustment based at least in part on a measure of energy content of the landfill gas being extracted from the at least some of the plurality of wells.

Assignees

• Loci Controls Inc

Inventors

• Quigley Peter
• Martin Ian
• Neff Nicole
• Rowbottom Jack

Classifications

• B09B1/00 Primary

  Dumping solid waste · CPC title

• B09C1/005

  Extraction of vapours or gases using vacuum or venting · CPC title

• B09B1/006 Primary

  Shafts or wells in waste dumps · CPC title

• Y02W30/30

  Landfill technologies aiming to mitigate methane emissions · CPC title

• E21B34/02

  in well heads · CPC title