Devices and techniques relating to landfill gas extraction

Patent metadata

Field	Value
Publication number	US-11072006-B2
Application number	US-202016745892-A
Country	US
Kind code	B2
Filing date	Jan 17, 2020
Priority date	Nov 4, 2013
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A control system for controlling extraction of landfill gas, comprising: at least one sensor configured to measure one or more characteristics of landfill gas; at least one flow control mechanism disposed in well piping and configured to control flow of the landfill gas through the well piping; and at least one processor configured to: obtain a measured concentration of a first gas in landfill gas; determine whether the measured concentration of the first gas is either less than a first threshold concentration or greater than a second threshold concentration; when it is determined that the measured concentration is less than the first threshold concentration, control the at least one flow control mechanism to reduce flow rate of landfill gas; and when it is determined that the concentration is greater than the second threshold concentration, control the at least one flow control mechanism to increase the flow rate of landfill gas.

First claim

What is claimed is:

1. A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the control system comprising:
at least one processor configured to:
obtain a measured concentration of a first gas in landfill gas extracted from the landfill;
determine whether the measured concentration of the first gas is either less than a first threshold concentration or greater than a second threshold concentration;
when it is determined that the measured concentration is less than the first threshold concentration, control at least one flow control mechanism to reduce flow rate of landfill gas through the at least one flow control mechanism; and
when it is determined that the measured concentration is greater than the second threshold concentration, control the at least one flow control mechanism to increase the flow rate of landfill gas through the at least one flow control mechanism.

2. The control system of claim 1 , wherein, when it is determined that the measured concentration is less than the first threshold concentration, the at least one processor is further configured to:
after controlling the at least one flow control mechanism to reduce the flow rate of the landfill gas through the at least one flow control mechanism,
obtain a second measured concentration of the first gas in landfill gas extracted from the landfill;
determine whether the second measured concentration of the first gas is less than the first threshold concentration; and
when it is determined that the second measured concentration of the first gas is less than the first threshold concentration, control the at least one flow control mechanism to further reduce the flow rate of landfill gas through the at least one flow control mechanism.

3. The control system of claim 1 , wherein, when it is determined that the measured concentration is greater than the second threshold concentration, the at least one processor is further configured to:
after controlling the at least one flow control mechanism to increase the flow rate of the landfill gas through the at least one flow control mechanism,
obtain a second measured concentration of the first gas in landfill gas extracted from the landfill;
determine whether the second measured concentration of the first gas is greater than the second threshold concentration; and
when it is determined that the second measured concentration of the first gas is greater than the second threshold concentration, control the at least one flow control mechanism to further increase the flow rate of landfill gas through the at least one flow control mechanism.

4. The control system of claim 1 , wherein the first gas is methane, and wherein the at least one processor is configured to determine whether the measured concentration of methane is less than the first threshold concentration at least in part by determining whether the measured concentration of methane is less than 45 percent of methane by volume.

5. The control system of claim 1 , wherein the first gas is methane, and wherein the at least one processor is configured to determine whether the measured concentration of methane is greater than the second threshold concentration at least in part by determining whether the measured concentration of methane is greater than 55 percent of methane by volume.

6. The control system of claim 1 , wherein the first threshold concentration is less than the second threshold concentration.

7. The control system of claim 1 ,
wherein the at least one flow control mechanism comprises at least one valve,
wherein the at least one processor is configured to control the at least one flow control mechanism to increase the flow rate of landfill gas at least in part by causing the at least one valve to open to a greater degree, and
wherein the at least one processor is configured to control the at least one flow control mechanism to decrease the flow rate of landfill gas at least in part by causing the at least one valve to close to a greater degree.

8. The control system of claim 1 , wherein the first gas is methane.

9. The control system of claim 1 , wherein the gas extraction system comprises at least one sensor, the at least one sensor comprising a sensor configured to detect partial pressure or concentration of methane.

10. The control system of claim 1 , wherein the gas extraction system comprises at least one sensor coupled to the at least one flow control mechanism.

11. The control system of claim 1 , wherein the at least one processor is located remotely from the at least one flow control mechanism and is configured to wirelessly communicate with the at least one flow control mechanism.

12. A method for controlling extraction of landfill gas from a landfill via a control system, the method comprising:
obtaining a measured concentration of a first gas in landfill gas extracted from the landfill,
determining whether the measured concentration of the first gas is either less than a first threshold concentration or greater than a second threshold concentration;
when it is determined that the measured concentration is less than the first threshold concentration, controlling at least one flow control mechanism to reduce the flow rate of landfill gas through the at least one flow control mechanism; and
when it is determined that the measured concentration is greater than the second threshold concentration, controlling the at least one flow control mechanism to increase the flow rate of landfill gas through the at least one flow control mechanism.

13. The method of claim 12 , wherein, when it is determined that the measured concentration is less than the first threshold concentration, the method further comprises:
after controlling the at least one flow control mechanism to reduce the flow rate of the landfill gas through the at least one flow control mechanism,
obtaining a second measured concentration of the first gas in landfill gas extracted from the landfill;
determining whether the second measured concentration of the first gas is less than the first threshold concentration; and
when it is determined that the second measured concentration of the first gas is less than the first threshold concentration, controlling the at least one flow control mechanism to further reduce the flow rate of landfill gas through the at least one flow control mechanism.

14. The method of claim 12 , wherein, when it is determined that the measured concentration is greater than the second threshold concentration, the method further comprises:
after controlling the at least one flow control mechanism to increase the flow rate of the landfill gas through the at least one flow control mechanism,
obtaining a second measured concentration of the first gas in landfill gas extracted from the landfill;
determining whether the second measured concentration of the first gas is greater than the second threshold concentration; and
when it is determined that the second measured concentration of the first gas is greater than the second threshold concentration, controlling the at least one flow control mechanism to further increase the flow rate of landfill gas through the at least one flow control mechanism.

15. The method of claim 12 , wherein the first gas is methane, and wherein determining whether the measured concentration of methane is less than the first threshold concentration comprises determining whether the measured concentration of methane is less than 45 percent of methane by volume.

16. The method of claim 12 , wherein the first gas is methane, and wherein determining

Assignees

• Loci Controls Inc

Inventors

• Campanella Andrew
• Michels Joseph G
• Quigley Peter
• Martin Ian

Classifications

• B09B1/006 Primary

  Shafts or wells in waste dumps · CPC title

• E21B43/00

  Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells (applicable only to water E03B) · CPC title