One dirty little secret left publicly unstated by outspoken proponents of increased Natural Gas usage, as a means to "cleanly" overcome our domestic energy shortage, is that, as we have earlier documented, Natural Gas is most often, as found in geologic reservoirs, already mixed with a large, sometimes surprisingly large, percentage of Carbon Dioxide.
That inherent CO2 content can be reduced by the Gas producer, with the extracted CO2 then most often, as we understand the literature, just released into the atmosphere; or, depending on concentrations, it can be simply passed along to the consumer, where it, along with the Gas combustion products, still eventually winds up in the atmosphere.
The enthusiastic claims of outspoken and wealthy proponents of increased reliance on Natural Gas, as some sort of economical, and "clean", energy alternative notwithstanding.
As we have also documented, producers of Natural Gas long ago recognized that fact and began developing ways in which it could be turned to advantage.
Herein, we see that Mobil Oil was one of the companies who addressed the issue, and developed a means by which such Carbon Dioxide-contaminated, and, thus, "low-BTU", Natural Gas could be further processed, through a technology that sounds very similar to the "tri-reforming" technology espoused, as we've reported, by Chunsan Song and Craig Grimes at Penn State University, and the CO2 and Methane reacted together with Steam in order to synthesize liquid hydrocarbons.
The technology disclosed herein should have implications obvious to anyone who has followed our posts thus far. We will, though, emphasize and reiterate some important facts, following excerpts from:
"United States Patent 4,098,339 - Utilization of Low BTU Natural Gas
Date: July, 1978
Inventors: Paul Weisz, PA, and John Zahner, NJ
Assignee: Mobil Oil Corporation, NY
Abstract: Natural gas of low heating value, high CO2 content, is converted to valuable products by the combination process of steam reforming the desulfurized gas, subjecting the effluent of the steam reformer to a water gas shift reaction and converting the resultant carbon dioxide, the unreacted carbon monoxide and hydrogen to liquid product useful as fuel, e.g. methanol. In a preferred embodiment, the gas phase separated from the liquid fuel products is processed to provide a gas sufficiently rich in carbon dioxide for use in tertiary recovery of petroleum from natural reservoirs which have produced the quantity of oil available by natural drive.
Claims: A process for economic utilization of natural gas having low heating value by reason of containing carbon dioxide in admixture with the methane content thereof, which process comprises subjecting a natural gas having substantial methane content in admixture with at least fifty volume percent of carbon dioxide based on total volume of said gas to the following steps in the sequence recited: (a) mixing said gas with water and reacting the mixture in contact with a catalyst to promote the reforming reaction of methane and water to produce carbon monoxide and hydrogen under temperature and pressure conditions conducive of said reforming reaction;
(b) reacting the product of step (a) in contact with a catalyst to promote the water gas shift reaction of a portion of the carbon monoxide with water to produce carbon dioxide and hydrogen under temperature and pressure conditions conducive of said shift reaction; and
(c) reacting the product of step (b), in contact with a carbon monoxide reduction catalyst for promotion of synthesis reaction between carbon dioxide, the unreacted carbon monoxide and hydrogen, to produce methanol or hydrocarbons, which are liquid at normal temperature of 70F and atmospheric pressure, under conditions of temperature and pressure conducive of said synthesis reaction thereby producing as the product of said synthesis reaction a mixture comprising:
(1) said methanol or hydrocarbons which are liquid at normal temperature of 70F and atmospheric pressure, and
(2) a gaseous by-product enriched in carbon dioxide as compared with said natural gas."
(b) reacting the product of step (a) in contact with a catalyst to promote the water gas shift reaction of a portion of the carbon monoxide with water to produce carbon dioxide and hydrogen under temperature and pressure conditions conducive of said shift reaction; and
(c) reacting the product of step (b), in contact with a carbon monoxide reduction catalyst for promotion of synthesis reaction between carbon dioxide, the unreacted carbon monoxide and hydrogen, to produce methanol or hydrocarbons, which are liquid at normal temperature of 70F and atmospheric pressure, under conditions of temperature and pressure conducive of said synthesis reaction thereby producing as the product of said synthesis reaction a mixture comprising:
(1) said methanol or hydrocarbons which are liquid at normal temperature of 70F and atmospheric pressure, and
(2) a gaseous by-product enriched in carbon dioxide as compared with said natural gas."
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Why not, instead, use the Sabatier process, as being further developed by NASA, as we've documented, to convert that leftover Carbon Dioxide into even more Methane, and, then, react that Methane with even more Carbon Dioxide - which can, as we've also documented, be, using environmental energy, recovered with adequate efficiency even from the atmosphere itself?
And, of course, lest we forget, Mobil knows how, using their MTG(r) technology, to further convert "said methanol", as synthesized above from reactions between CO2 and CH4, into Gasoline.