Recovery of Argon from Hydrocarbon Furnace Exhaust Streams
Publication Date: 2017-Feb-03
The IP.com Prior Art Database
A method for recovering argon from a combustion exhaust gas from a hydrocarbon furnace is disclosed, the combustion exhaust gas comprising carbon dioxide,oxygen, nitrogen and argon.
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 Recovery of Argon from Hydrocarbon Furnace Exhaust Streams
 BACKGROUND OF THE INVENTION
 Hydrocarbon furnace power plants typically produce considerable combustion exhaust
streams containing a variety of gases (i.e., flue gases), including carbon dioxide (CO2), oxygen (O2),
nitrogen (N2), and argon (Ar). Emission of these gases into the atmosphere—particularly carbon
dioxide and other greenhouse gases—is an ever-present concern, and techniques have been
developed to lessen such emissions.
 One technique, referred to as oxy-fuel combustion, involves replacing air that is
ordinarily used to burn fuel in hydrocarbon furnaces with an oxygen-enriched gas mixture (e.g., 95%
oxygen). Using an oxygen-enriched gas mixture as the oxidant produces significantly lower volumes
of combustion exhaust gases. Further, using an oxygen-enriched gas mixture decreases nitrogen
oxide (NOx) production and results in a combustion exhaust stream primarily consisting of water
(H2O) and carbon dioxide, which can make subsequent purification of the combustion exhaust
stream more efficient. The water in the combustion exhaust stream can be removed by condensation,
and the carbon dioxide can be sequestered. For example, compressed carbon dioxide can be
sequestered by pumping it into depleted underground oil and natural gas reservoirs or saline aquifers
for long-term storage rather than being vented into the atmosphere. Alternatively, the carbon dioxide
can be used for enhanced oil recovery (EOR).
 After the combustion exhaust stream is compressed for carbon dioxide separation and
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sequestration, the resulting pressurized waste stream is usually vented to the atmosphere or expanded
to drive a turbine for power generation. This waste stream, however, has a relatively high
concentration of argon (e.g., ten- to twenty-eight-fold increase in argon concentration) as compared
to air, and such an argon-enriched gas stream can have significant value in terms of both the value of
argon and the ability to recover argon from the stream with less cost and greater efficiency.
 Accordingly, there is an unmet need for improved, cost-effective systems and processes
that enable an argon gas stream to be recovered from hydrocarbon furnace exhaust streams.
 BRIEF DESCRIPTION OF THE DRAWINGS
 The present invention will hereinafter be described in conjunction with the appended
drawing figures wherein like numerals denote like elements.
 Figure 1 is a block diagram of a production system in accordance with a first exemplary
embodiment of the invention.
 Figure 2 is a block diagram of a production system in accordance with a second
exemplary embodiment of the invention.
 Figure 3 is a block diagram of a production system in accordance with a third exemplary
embodiment of the invention.
 Figure 4 is a block diagram of a production system in accordance with a fourth exemplary