Landfill Gas Treatment Method With Polishing
First Claim
1. A method for using a solvent in treating a gas from a landfill, wherein the gas and the solvent have a varying concentration of carbon dioxide, the method comprising:
- conveying the gas through a main absorber;
conveying substantially all of the gas from the main absorber through a polishing absorber;
conveying at a main mass flow rate a main current of solvent through the main absorber, thereby exposing the gas to the main current of solvent;
the main current of solvent extracting carbon dioxide from the gas;
conveying at a polishing mass flow rate a polishing current of solvent through the polishing absorber, thereby exposing the gas to the polishing current of solvent; and
the polishing current of solvent extracting additional carbon dioxide from the gas, the main mass flow rate through the main absorber being at least three times greater than the polishing mass flow rate in the polishing absorber.
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Abstract
A method for recovering methane gas from a landfill involves the use of a main absorber, a flash system, an optional ancillary absorber and an optional polishing absorber. The recovered gas is maintained at a temperature that enhances a solvent'"'"'s ability to absorb carbon dioxide from the recovered gas. While the main absorber uses the solvent for absorbing most of the carbon dioxide from the recovered gas, the flash system removes much of the carbon dioxide from the solvent exiting the main absorber. In some examples, at least portion of the flash system operates at subatmospheric pressure to create a vacuum that draws in a generally inert stripper gas (e.g., air, nitrogen, etc.) at atmospheric pressure. The stripper gas helps remove carbon dioxide from the solvent in the flash system.
27 Citations
5 Claims
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1. A method for using a solvent in treating a gas from a landfill, wherein the gas and the solvent have a varying concentration of carbon dioxide, the method comprising:
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conveying the gas through a main absorber; conveying substantially all of the gas from the main absorber through a polishing absorber; conveying at a main mass flow rate a main current of solvent through the main absorber, thereby exposing the gas to the main current of solvent; the main current of solvent extracting carbon dioxide from the gas; conveying at a polishing mass flow rate a polishing current of solvent through the polishing absorber, thereby exposing the gas to the polishing current of solvent; and the polishing current of solvent extracting additional carbon dioxide from the gas, the main mass flow rate through the main absorber being at least three times greater than the polishing mass flow rate in the polishing absorber. - View Dependent Claims (2, 3, 4, 5)
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Specification