WV Coal Member Meeting 2024 1240x200 1 1

Mobil Improves Coal Conversion Catalysis

United States Patent: 4686313

 

We know that we've beaten the ExxonMobil "MTG"(r), methanol-to-gasoline technology, nearly to death.

In that process, as we're certain you will by now recall, Coal is first converted into Methanol; and, the Methanol is then converted into Gasoline.

Like some other Coal conversion technologies, arising from other sources, we have documented for you, zeolite minerals, - - synthetic versions of which, interestingly, and again as we've earlier documented, can be harvested in abundance from Coal-fired power plant fly ash - - most especially one designated as "ZSM-5", are specified as catalysts which facilitate, in ExxonMobil's technology, the condensation of Methanol from synthesis gas made from Coal, and, as we understand it, the subsequent transformation of that Methanol into Gasoline.

We further remind you that Exxon's process is not the only one which enables the production of Methanol from Coal. We have many time documented the fact that Eastman Chemical Company is, and has for some years been doing, just that at their plant in Kingsport, Tennessee. And, there are other, international, examples of the process in use, as well.

In any case, herein, from very nearly a quarter of a century ago, Mobil Oil further explains how Coal can be transformed into Methanol; and, through Methanol, into Gasoline.

As in many other oil industry US Patents we've brought to your attention and commented on, these Big Oil scientists avoid, in as much as is possible, any use of the dirty, four-letter word, Coal.

The potential sources of their "synthesis gas" are explained only once, and we reproduce the pertinent passage, as a foreword to our more extended excerpts, as follows:

"Processes are known for converting coal ... to a gaseous mixture consisting essentially of hydrogen and carbon monoxide and/or dioxide. Those of major importance depend either on the partial combustion of the fuel with an oxygen-containing gas or on the high temperature reaction of the fuel with steam, or on a combination of these two reactions."

The foregoing will be seen again, so the point isn't lost, in our more extended excerpts from:

 

"US Patent 4,686,313 - Fischer-Tropsch Catalyst and Conversion of Synthesis Gas Therewith

 

Date: August, 1987

 

Inventors: Weldon Bell, et. al., NJ

 

Assignee: Mobil Oil Corporation, NY

 

Abstract: Synthesis gas (a mixture of hydrogen gas and carbon monoxide) is converted to hydrocarbons by flowing the gas first over iron-containing Fischer-Tropsch catalyst and then over a zeolite.

Claims: (A) process for converting syngas to hydrocarbons comprising: contacting an iron-containing Fischer-Tropsch catalyst with a syngas stream under conditions effective to achieve high conversion of said syngas to substantial amounts of C3 + carbon compounds; contacting (that product) with a ... crystalline zeolite  (and) recovering from the effluent stream ... gasoline and distillate materials.

(And) wherein the zeolite is ZSM-5.

Description: This invention is concerned with low nitrogen Fischer-Tropsch catalyst, a method of preparing such catalyst, and an improved process for converting synthesis gas, i.e. mixtures of gaseous carbon oxides with hydrogen or hydrogen donors, to hydrocarbon mixtures. 

Processes are known for converting coal ... to a gaseous mixture consisting essentially of hydrogen and carbon monoxide and/or dioxide. Those of major importance depend either on the partial combustion of the fuel with an oxygen-containing gas or on the high temperature reaction of the fuel with steam, or on a combination of these two reactions.

It is also known that synthesis gas will undergo conversion to reduction products of carbon monoxide, such as hydrocarbons ... over a fairly wide variety of catalysts. The Fischer-Tropsch (F-T) process, for example, which has been most extensively studied, produces a range of liquid hydrocarbons, a portion of which have been used as low octane gasoline.

Recently, it has been discovered that the conversion of synthesis gas into valuable products can be greatly enhanced by employing a special type of crystalline zeolite exemplified by ZSM-5 in admixture with a carbon monoxide reduction catalyst. Thus, for example, in United States Patent: 4086262 (Conversion of Synthesis Gas to Hydrocarbon Mixtures), incorporated herein by reference, there is disclosed a process for the conversion of syngas by passing the same at elevated temperature over a catalyst which comprises an intimate mixture of a Fischer-Tropsch component and a shape-selective zeolite such as ZSM-5. Said patent points out that the products produced are hydrocarbon mixtures which are useful in the manufacture of heating oil, high octane gasoline, aromatic compounds, and chemical intermediates.

(We believe that we have previously reported the prior art US Patent 4,086,262. But, we will double-check to make certain. In any case, note that the "low octane gasoline" generated, as above, from Coal syngas, can, instead, when ZSM-5 zeolite is added to the basic Fischer-Tropsch catalyst, be a "high octane gasoline", which is produced along with some other useful things.)

More recently it has been discovered that a highly aromatic or highly olefinic gasoline of enhanced octane number or a gasoline plus distillate mixture can be obtained in greater yield from synthesis gas utilizing a selected synthesis gas composition of low H2 /CO ratio in a specialized Fischer-Tropsch syngas conversion operation and in a sequentially arranged dual reactor conversion process. Such a process is described in

United States Patent: 4279830 (Conversion of Synthesis Gas Using Dual Reactors), which is incorporated herein by reference. The process basically is a two-stage process comprising reacting the syngas mixture in a first stage in the presence of a special Fischer-Tropsch CO reducing catalyst under preselected conditions. The product obtained from this first stage syngas conversion is thereafter processed in a second stage reactor with a shape-selective crystalline zeolite catalyst of a desired activity to yield a synthetic hydrocarbon product containing a gasoline fraction ... .

This is a divisional of copending application Ser. No. 687,695 ... now United States Patent: 4617288 (Low Nitrogen Fischer-Tropsch Catalyst)."

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Note, that, in a way similar to other, like, technologies we have already brought to your attention, Mobil herein specifies use of a "synthesis gas composition of low H2 /CO ratio" as could be obtained from one of  the processes already "known for converting coal ... to a gaseous mixture consisting essentially of hydrogen and carbon monoxide", wherein Steam is not employed as one of the agents of gasification.

This Mobil Gasoline synthesis process can utilize, it seems, a "low H2 /CO ratio" syngas, as could be derived from the, perhaps simpler and less expensive, generation of synthesis gas from Coal via partial oxidation only with air, or purified Oxygen; and, without the added complexity and expense of generating and adding Steam to the mix of gases with which the Coal is gasified.

In any case, from very nearly one quarter of a century ago, we have herein even more United States Government-certified statement of the facts, that:

We can first convert "coal ... to a gaseous mixture consisting essentially of hydrogen and carbon monoxide and/or dioxide" and, then, convert that synthesis gas into "hydrocarbon mixtures which are useful in the manufacture of heating oil (and) high octane gasoline".