Landfill gas extraction control system throttle

Patent metadata

Field	Value
Publication number	US-2020016640-A1
Application number	US-201916510167-A
Country	US
Kind code	A1
Filing date	Jul 12, 2019
Priority date	Jul 13, 2018
Publication date	Jan 16, 2020
Grant date	—

Abstract

A system for extracting landfill gas from a landfill is provided. According to some embodiments, a control system for landfill gas extraction is provided. The control system uses a throttle to control flow of landfill gas extracted from the landfill. The throttle is actuated in use to vary the flow of gas between a well and a gas collection system, in accordance with a control algorithm that adjusts flow as a parameter in controlling gas extraction. The throttle is configured to ensure that there is at least some flow of landfill gas from the landfill to a gas output throughout operation. The extraction system provides an efficient system for landfill gas extraction, while mitigating a risk of creating undesired or unpleasant conditions and/or of violating regulations during operation.

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 gas extraction system comprising well piping for coupling at least one well to a gas output, the control system comprising:
a throttle disposed in the well piping and configured to restrict a flow of landfill gas, wherein at least some landfill gas can flow through the well piping with the throttle at a position of maximum closure; and a controller configured to control a position of the throttle to control the flow of landfill gas.

2 . The control system of claim 1 , wherein the throttle is configured to:
block a variable portion of an aperture through which the landfill gas flows.

3 . The control system of claim 1 , wherein the throttle comprises a plate configured to restrict the flow of landfill gas.

4 . The control system of claim 3 , wherein controlling the position of the throttle comprises rotating the plate.

5 . The control system of claim 3 , wherein controlling the position of the throttle comprises sliding the plate along a plane intersecting the flow of landfill gas.

6 . The control system of claim 3 , wherein the plate comprises a perforation configured to allow at least some landfill gas flow through the throttle at the position of maximum closure.

7 . The control system of claim 4 , wherein the throttle comprises a mechanism to limit a rotation range of the plate.

8 . The control system of claim 7 , wherein the mechanism to limit the rotation range is configured to limit rotation between a first position of 0 degrees at a position of minimum closure and a second position of 90 degrees at the position of maximum closure.

9 . The control system of claim 1 , wherein the throttle comprises a ball valve, the ball valve comprising a first perforation and a second perforation, the second perforation configured to allow at least some flow through the ball valve at the position of maximum closure.

10 . The control system of claim 1 , wherein the throttle is configured to allow at least 1% of a flow of landfill gas through the throttle at a position of minimum closure.

11 . The control system of claim 1 , wherein the throttle is configured to maintain a difference in pressure between upstream and downstream of the throttle greater than 0 mbar.

12 . The control system of claim 1 , wherein the flow of landfill gas through the throttle at the position of maximum closure is at least 0.1 cubic feet per minute.

13 . The control system of claim 1 , wherein the throttle comprises a motor configured to adjust a variable portion of an aperture through which the landfill gas flows.

14 . The control system of claim 13 , wherein the motor is configured to use less than 10 watts to adjust the position of the throttle.

15 . The control system of claim 13 , wherein the motor has a volume less than or equal to 10 inches cubed.

16 . The control system of claim 13 , wherein the throttle comprises a gear box configured to prevent back-drive of the throttle.

17 . The control system of claim 13 , wherein the throttle comprise:
a battery source to power the motor; and a solar panel to charge the battery.

18 . The control system of claim 1 , wherein the throttle is configured to provide control of the flow rate on a continuous scale.

19 . The control system of claim 1 , wherein the throttle has a weight less than 3 lbs.

20 . The control system of claim 1 , further comprising a flow measurement device configured to obtain a measurement of flow rate of landfill gas through the throttle, wherein the controller is configured to control the position of the throttle based at least on the obtained measurement of flow rate.

21 . The control system of claim 20 , wherein the flow measurement device comprises an orifice plate.

22 . The control system of claim 20 , wherein the flow measurement device comprises a venturi meter.

23 . The control system of claim 20 , wherein the flow measurement device comprises a pitot tube.

24 . The control system of claim 20 , wherein the flow measurement device comprises one of an optical flow meter or a thermal mass flow meter.

25 . The control system of claim 1 , further comprising:
a pressure sensor configured to obtain a measurement of pressure upstream of the throttle; wherein the controller is configured to control the position of the throttle based at least on the obtained measurement of the pressure upstream of the throttle.

26 . A method of controlling extraction of landfill gas from a landfill via a gas extraction system, the method comprising:
obtaining, using a sensor, a measurement of a characteristic of landfill gas extracted from the landfill; controlling a flow of landfill gas extracted from the landfill based at least in part on the measurement of the characteristic, wherein the controlling comprises allowing at least some flow of landfill gas from the landfill to a gas output.

27 . The method of claim 26 , wherein obtaining, using the sensor, the measurement of the characteristics of landfill gas comprises measuring a concentration of methane, oxygen, and/or carbon dioxide in the landfill gas.

28 . The method of claim 26 , wherein controlling the flow of landfill gas comprises controlling a position of a throttle configured to restrict a flow of landfill gas through the throttle.

29 . The method of claim 26 , wherein controlling the position of the throttle comprises controlling a rotational position of a plate.

30 . The method of claim 26 , wherein controlling the position of the throttle comprises controlling a linear position of a plate along a plane intersecting the flow of landfill gas.

31 . The method of claim 26 , further comprising controlling the position of the throttle with a motor using less than 10 watts of power.

32 . The method of claim 26 , further comprising maintaining flow of landfill gas from the landfill to the gas output at least at 0.1 cubic feet per minute.

33 . The method of claim 26 , further comprising maintaining a difference in pressure between upstream and downstream of the throttle greater than 0 mbar.

34 . The method of claim 31 , wherein controlling the position of the throttle with the motor comprises:
drawing electrical power when changing the position of the throttle; and holding the throttle in position with a gearbox.

35 . 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 at least one well to a gas output, the control system comprising:
a plate disposed in the well piping and configured to control a size of an area through which extracted landfill gas flows, wherein the plate, when in a position of maximum closure, is configured to allow at least some flow of landfill gas through the area; a controller configured to control a position of the plate to control the size of the area through which the extracted landfill gas flows.

36 . The control system of claim 35 , wherein the controller is configured to control a rotational position of the plate.

37 . The control system of claim 36 , fu

Assignees

• Loci Controls Inc

Inventors

• Hale Mike
• Hale Keith
• Sims Melinda

Classifications

• E21B43/12 Primary

  Methods or apparatus for controlling the flow of the obtained fluid to or in wells (E21B43/25 takes precedence; valve arrangements E21B34/00) · CPC title

• B09B1/006 Primary

  Shafts or wells in waste dumps · CPC title

• F16K1/222

  Shaping of the valve member · CPC title

• B09B1/00

  Dumping solid waste · CPC title

• E21B34/00

  Valve arrangements for boreholes or wells · CPC title