Process for the conversion of a normally gaseous hydrocarbon to carbon monoxide and hydrogen

 

The title of the US Patent we enclose in this dispatch, relative to our headline label, might at first seem misleading, since it doesn't mention Coal, but only "gaseous hydrocarbon".

A close read of the full document reveals, however, that the subject "gaseous hydrocarbon" is, or can be, generated by, specifically,  "the gasification of coal with oxygen and steam".

And, the entire, though obliquely stated, purpose of this US Government-approved technology is to "improve" the product gas obtained by such Coal gasification, and "particularly" when it is to be used "as a feed for the Fischer-Tropsch synthesis", wherein, as the Disclosure states, "hydrogen and carbon monoxide are converted into hydrocarbons, including those in the gasoline range and ... alcohols".

Brief comment follows more complete excerpts from:

 

"US Patent 2,942,958 - Conversion of a Normally Gaseous Hydrocarbon to Carbon Monoxide and Hydrogen

 

Date: June, 1960

 

Inventor: John Dwyer, NY

 

Assignee: The M.W. Kellogg Company, NJ

 

Abstract: This invention relates to the preparation of a gas rich in hydrogen. In one aspect the invention relates to the preparation of a feed gas comprising hydrogen and carbon monoxide suitable for the synthesis of hydrocarbons.

In the gasification of coal with oxygen and steam at elevated pressures by modern methods, as exemplified by the Lurgi process, considerable amounts of methane are produced along with hydrogen.

Although this methane-containing gas is useful for many purposes, it is desirable to improve it considerably, particularly when used in a hydrogenation process of as a feed for the Fischer-Tropsch hydrocarbon synthesis (wherein) hydrogen and carbon monoxide are converted into hydrocarbons, including those in the gasoline range.

Methane and other gaseous hydrocarbons are not polymerized in the Fischer-Tropsch process; therefore, greater efficiency can be realized by converting methane and gaseous hydrocarbon components of synthesis feed gas into hydrogen and carbon monoxide.

In the gas preparation method described herein ... this is accomplished by the partial combustion of a portion of the methane with oxygen and the reformation of another part of methane with steam. By this means synthesis feed gases with methane content below 5 volume percent can be economically prepared from gases containing sizeable amounts of methane.

(And) the process of the present invention is specifically disclosed in connection with modifying a coal gas into a synthesis feed ... .

 

(Objects of the present invention are):

 

(To) provide an improved method for the preparation of a gas rich in hydrogen.

 

(To) provide an improved method for the preparation of a hydrocarbon synthesis feed gas comprising hydrogen and carbon monoxide.

 

(To) provide an improved method for the conversion of coal gas into a hydrocarbon synthesis feed gas.

 

(And, to) increase the conversion of methane ... to hydrogen and oxides of carbon with a minimum of carbon formation in the reaction zone.

 

The present invention relates to a process for the simultaneous partial combustion and reforming of a normally gaseous hydrocarbon ... in the presence of sufficient steam to both prevent carbon deposition and to shift the reaction equilibrium to promote the formation of hydrogen ... .

(The) invention relates to the production of a hydrocarbon synthesis feed from a mixture of coal gas and recycled product gas from the synthesis reactor.  By this process it is possible to produce additional hydrogen and carbon monoxide in a mole ratio exceeding 2:1 respectively. This is important inasmuch as superior results have been obtained in hydrocarbon synthesis in which the feed contained more than (twice as much) hydrogen (as) carbon monoxide.

The charge gas ... is derived from the gasification of coal ... .

(And, it) is often desirable to recycle a portion of the gaseous components of the hydrocarbon synthesis effluent in order to utilize its content of light hydrocarbons. Accordingly, after removal of oxygenated organic compounds and hydrocarbons containing more than three carbon atoms, part of the cooled synthesis gas is optionally returned to the plant ... ."

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There are several points worthy of emphasis in this half-century-old technology, now owned by "KBR", aka Kellogg, Brown & Root, the Texas-based oil industry services company.

One is that Methane can be generated, along with Carbon Monoxide and Hydrogen hydrocarbon synthesis gas, via the Steam-gasification of Coal, as in the specified Lurgi process.

Now, assuming that we didn't want to reclaim the Methane, and react it with reclaimed Carbon Dioxide, from whatever source, and, through such "reforming" reactions, generate hydrocarbons, we can, as herein, cycle the Methane, in confirmation of earlier of our reports, back into the system, react it with more Steam, and thereby generate additional, Hydrogen-rich synthesis gas with a Methane content "below 5 volume percent".

And, by such a "process it is possible to produce additional hydrogen and carbon monoxide in a mole ratio exceeding 2:1 respectively. This is important inasmuch as superior results have been obtained in hydrocarbon synthesis in which the feed contained more than (twice as much) hydrogen (as) carbon monoxide".

Finally, this is just further confirmation of many of our earlier reports, in that:

We can make hydrocarbon synthesis gas, consisting of Hydrogen and Carbon Monoxide, in whatever ratios we might want, for direction into a variety of end-use hydrocarbon synthesis processes, in compositions which can be varied, according to the end hydrocarbon product desired, simply by varying and adjusting the amount of Steam that is reacted, in the first place, with Coal, to generate synthesis gas; and, then, by manipulating some components of that synthesis gas through additional reactions with more Steam.

Kellogg only generally specifies some of the end products which can be obtained as including "oxygenated organic compounds and hydrocarbons containing more than three carbon atoms".

We submit that Methanol is representative of  "oxygenated organic compounds"; and, that "hydrocarbons containing more than three carbon atoms" do include those, as Kellogg specifies "in the gasoline range".


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