Exxon Improves Coal Hydrogasification

United States Patent: 4204843

 

Herein is further confirmation of a fact which we have, from other sources, previously documented:

Treating Coal, prior to steam-gasification done to generate a fully-hydrogenated hydrocarbon synthesis gas, with certain alkali metal hydroxides, such as you might find in inexpensive drain cleaners, can improve the rate and efficiency of Coal's conversion into such hydrocarbon syngas.

Exxon figured that out for themselves, as confirmed herein by our United States Government, a shade more than three decades ago.

Comment follows excerpts from:

 

"United States Patent 4,204,843 - Gasification Process

 

Date: May, 1980

 

Inventor: Richard Neavel, TX

 

Assignee: Exxon Research and Engineering Company, NJ

 

Abstract: A novel process, and the compositions of matter formed thereby, wherein Group II-A metals, or compounds thereof, can be ion-exchanged onto coal, preferably a high rank coal, notably a subbituminous or bituminous coal, by soaking the coal in an alkali solution of a Group I-A metal compound sufficient to incorporate said metal compound, or cation portion thereof, into said coal to form ion-exchange sites, and ion-exchanging, and thereby replacing all or a portion, preferably a portion, of the Group I-A metal cations with said Group II-A metals.

Enhanced gasification rates are achieved by gasification of the so-treated coal ... .

Claims: A process for gasifying coal ... to produce a fuel gas, which consists essentially of: soaking said coal with a solution comprising a Group I-A metal hydroxide (and, subsequently) contacting the coal with a Group II-A metal compound ... (to) replace a portion of the Group I-A metal cations ...  and then gasifying said treated coal at gasification conditions in a gasification zone to produce fuel gas. 

The process ...wherein the coal subjected to treatment with said Group I-A and Group II-A compounds is a bituminous coal (and) wherein the Group I-A metal is sodium or potassium (and) wherein the Group II-A metal is calcium.

Background and Summary: Before the turn of the century it was known that hydrocarbon gases and liquids, tars and chemicals could be obtained not only from petroleum, but from coal ... .

(Something we seem to have forgotten by the turn of the following century.)

Very early processes employed destructive distillation, coal being transformed into gases and petroleum-like liquid products. Primary emphasis in many of these processes is on gasification of the coal with the objective of improving processes for the production of water gas, producer gas, or hydrogen, as opposed to the production of coal liquids.

(Currently) intensive research and development efforts are now underway to produce synthetic high-BTU, intermediate-BTU and synthesis fuel gases for commercial usages.

The thrust of present research is to develop processes for the production of synthetic high-BTU gases with far higher efficiencies than was possible in the classical European, or early Euro-American processes.

(Note: Does anyone, any regular citizen resident in US Coal Country, have the slightest idea that there even were such earlier Coal conversion technologies, so old that they could be described as "classical"?)

In a catalytic coal gasification process ... steam, and particulate coal are fed to a gasifier at elevated temperature and pressure and converted to a synthesis gas, or gaseous mixture of high methane content, which contains significant amounts of carbon monoxide and hydrogen.

There is ... need for providing better catalytic coal gasification processes, or catalysts for use in catalytic coal gasification processes which are capable of producing high-BTU fuel gases from various coals, particularly high rank coals for commercial usages at improved economies, or efficiencies. 

It is, accordingly, the primary objective of the present invention to supply this need.

In a catalytic coal gasification process ... steam, and particulate coal are fed to a gasifier at elevated temperature and pressure and converted to a synthesis gas, or gaseous mixture of high methane content, which contains significant amounts of carbon monoxide and hydrogen ... .

The process of this invention is generally applicable for the inclusion of Group I-A and Group II-A metals in virtually any rank of coal, including ... bituminous coals such as Illinois No. 6, Pittsburgh No. 8 and the like.  

Group I-A metals, or alkali metals, suitable for the practice of this invention are exemplified by lithium, sodium, potassium, rubidium and cesium, the effectiveness of the metals as gasification catalysts increasing in direct proportion to their increased atomic weight, though sodium and potassium are preferred metals based on cost-effectiveness. These are suitably employed as salts or hydroxides, e.g., sodium carbonate, potassium hydroxide, potassium nitrate, cesium nitrate and the like. Suitable Group II-A metals, or alkaline earth metals, are exemplified by magnesium, calcium, strontium and barium ... .

(Nothing is needed, in other words, that could be described as rare and exotic - or expensive.)

It is, accordingly, the primary objective of the present invention to ... provide a process for the treatment of coals, notably high rank coals, ... to render such coals amenable to gasification at increased rate, with high activities, particularly for use in the production of high-BTU fuel gases. 

A further object is to provide, as compositions or articles of manufacture, a pretreated particulate coal feed which has been rendered amenable to gasification by treating to form therein relatively inexpensive species of Group I-A or Group II-A metals, or admixtures thereof, in high concentrations."

-----------

 

In sum, Exxon knows how to effect the gasification of "steam, and particulate coal", such as from, for instance, the "Pittsburgh No. 8" seam, in order to generate a "gaseous mixture of high methane content, which contains significant amounts of carbon monoxide and hydrogen".

Thus, from such "steam, and particulate coal", we can, "at increased rate" manufacture two things:

First, "methane" - which can be reacted with Carbon Dioxide, in bi-reforming and tri-reforming processes, to synthesize higher hydrocarbons; such as described best for us so far, as we've documented, by scientists at Penn State University; but, as we're documenting further today with transmission of a report concerning: "United States Patent 5,989,457 - Process for the Production of Synthesis Gas; November, 1999; Assignee: Mannesmann & K.T.I. Group, Germany; Abstract: A catalyst for the production of synthesis gas (CO and H2) by reaction of CO2 and CH4 and/or other light hydrocarbons".

And, concurrently, "significant amounts of carbon monoxide and hydrogen" - which, we submit, would constitute a synthesis gas ideally suited for Fischer-Tropsch, or related, catalytic condensation into additional liquid hydrocarbons - are generated from that "steam, and particulate coal", along with the Methane.

For more than three decades, our US Government has known, as herein officially, that we, those of US citizens resident in northern West Virginia and western Pennsylvania, can efficiently convert the abundant Pittsburgh seam Coal, which underlies parts of our states and Ohio, into both Methane and a co-product hydrocarbon synthesis gas.