We have previously cited the carbon conversion work of Richard Noceti, and colleagues, at the USDOE Pittsburgh (PA) Technology Center.
Although we would prefer to avoid redundancy, we must again reference Noceti, and colleague Charles Taylor, as they herein affirm that Methane, once it has been generated by Coal gasification or Sabatier-type Carbon Dioxide recycling and conversion, can itself be converted into gasoline.
We submit their report of this work as further confirmation that technologies, multiple technologies, exist, which would, if reduced to practice, enable the United States to achieve some level of domestic liquid fuel self sufficiency, an improving environment through greenhouse gas recycling, and, through increased reliance on domestic resources, a dramatically improved economy.
However, we append what we think to be important comment following the excerpt:
"CONVERSION OF METHANE TO GASOLINE-RANGE HYDROCARBONS
Charles E. Taylor and Richard P. Noceti
U.S. Department of Energy
Pittsburgh Energy Technology Center
P.O. Box 10940
Pittsburgh, PA 15236
Existing processes have been assembled in a novel combination capable of producing higher hydrocarbons from methane with high yield and selectivity. Methane, oxygen, and hydrogen chloride react over an oxyhydrochlorination (OHC) catalyst in the first stage to produce predominantly chloromethane and water. In the second stage, the chloromethane is catalytically converted to higher hydrocarbons, namely, paraffins, cycloparaffins, olefins, and aromatics, by an alumino-silicate zeolite. In the process described, the final hydro- carbon mixture is largely in the gasoline (C4-C10) boiling range.
Current technology for the conversion of methane to more useful compounds includes steam reforming reactions; halogenation; oxychlorination; oxidation, including oxidative coupling and metal oxide reactions; reaction with superacids; and various other methods. At present, these conversion schemes are unattractive because they are marked by low overall carbon conversions or poor selectivities.
In 1975, Mobil Oil Corporation patented a process.for the conversion of methanol to higher ,hydrocarbons by reaction over a zeolite catalyst, such as ZSM-5. Although later Mobil patents claimed that ZSM-5 wouId convert any monofunctionalized methane to higher hydrocarbons, methanol was the feedstock of interest.
In work done by Allied Chemical Corporation, Pieters, et al., reported the selective functionalization of methane by reaction with oxygen and hydrogen chloride over a supported copper chloride catalyst to give tetrachloromethane as the major product. The advantages of the Allied process are significant.
The work described below demonstrates that an effective method for selective functionalization in combination with oligomerization over a zeolite catalyst provides a facile route for conversion of methane to higher hydrocarbons.
The zeolite catalyst was regenerated by exposure to oxygen at temperatures between 350° and 550°C until the presence of carbon dioxide in the effluent stream was no longer detected by the mass spectrometer.
Removal of carbon restored the catalyst to its initial activity even after 14 cycles.
RESULTS
Conversion of methane to chloromethane
The conversion of methane to chloromethane has been observed under various reaction conditions. The data show a material balance around 100% and display several trends. ... methane conversion and polychlorination both increase as residence time and temperature increase.
Production of carbon dioxide and formic acid, undesirable by-products, also varied with residence time and temperature. As either the residence time or temperature increased, the amount of carbon dioxide increased while the amount of formic acid decreased. Carbon monoxide was not detected in the product stream.
Conversion of chloromethane to gasoline
Conversion of chloromethane over ZSM-5 to gasoline-range hydrocarbons has been observed to occur under conditions similar to those for the conversion of methanol. Two forms of the oligomerization catalyst were used in this study. One was a sample of iron-promoted ZSM-5 synthesized in our laboratory; the other was a sample of H-ZSM-5 obtained from Mobil Oil Corporation. Both catalysts produced similar products under the same reaction conditions.
Conclusion
Methane has been converted to higher hydrocarbons boiling in the gasoline range by the two-stage process described."
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Although it is herein documented that Methane, as could be produced by Coal gasification or the Sabatier recycling of Carbon Dioxide, can be converted almost directly into higher, "gasoline-range hydrocarbons", there might be an even better use for it, a better way to convert it into those higher hydrocarbons.
Methane could, instead, be reacted with even more Carbon Dioxide in a "Tri-reforming" process, as described by Song and Grimes, et. al., at Penn State University, and as we have documented in our recent reports. If Methane produced by Sabatier CO2 recycling technology were employed in that process, even more Carbon Dioxide would thus be utilized and consumed.
One contrary note: "Formic acid" is referred to herein as an "undesirable by-product". Actually, formic acid does have practical applications, including use in fuel cells, which might have evolved since this report was issued. It does now have commercial value, and if it is produced in significant quantity, it could represent another income stream for this technology.
In any case, it is again demonstrated that multiple technologies exist which would, if reduced to commercial practice, enable all US citizens to enjoy the economic and international relations benefits of a domestic liquid fuel self-sufficiency based on Coal; on products, like Methane, which can be made from Coal; and, on the byproducts, such as Carbon Dioxide, of Coal use.