As we've been occasionally documenting, most recently in:
West Virginia Coal Association | General Electric 2010 Hydrogen from Sunlight and Water | Research & Development; concerning: "United States Patent 7,820,022 - Photoelectrochemical Cell and Method of Manufacture; 2010; General Electric Company; Background and Field: This invention relates generally to an apparatus for producing hydrogen directly from solar energy. More particularly, this invention relates to hydrogen production using a photoelectrochemical cell";
technologies have been and are being developed which would enable us to begin using freely-available environmental energy to extract, from an essentially free resource, Water, elemental Hydrogen.
And, we've documented the value of such molecular Hydrogen in some rather direct Coal conversion processes, where the Hydrogen can be used to hydrogenate Coal, resulting in the straightforward production of hydrocarbon liquids and gases. One example is seen in our report of:
West Virginia Coal Association | California Rocket Scientists Liquefy Coal | Research & Development; concerning: "United States Patent 4,169,128 - Coal Liquefaction Apparatus; 1979; Assignee: Rockwell International Corporation, (CA); An apparatus for reacting (Coal) with hydrogen to produce hydrocarbon liquids and gases which (includes) electrical heating means for heating said source of hydrogen".
Herein, we learn that such direct Coal hydrogenation processes, wherein hot, gaseous Hydrogen is reacted directly with Coal, have been developed as well a little more lately and closer to home; and, by someone who should, and we use the word "should" advisedly, have all of our best interests at heart.
As seen in excerpts from the initial link in this dispatch, with additional links and excerpts appended:
"United States Patent 4,735,706 - Process and Apparatus for Coal Hydrogenation
Patent US4735706 - Process and apparatus for coal hydrogenation - Google Patents
Date: April, 1988
Inventor: John A. Reuther, McMurray, PA
Assignee: The United States of America
(Note, though not clearly spelled out in this document, the second US Patent we include in this dispatch clearly identifies Inventor John Reuther to be an employee of the USDOE in Pittsburgh, PA.)
Abstract: In the coal liquefaction process, an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture of agglomerates, excess water, dissolved catalyst, and unagglomerated solids is pumped to reaction pressure and then passed through a drainage device where all but a small amount of surface water is removed from the agglomerates. Sufficient catalyst for the reaction is contained in surface water remaining on the agglomerates. The agglomerates fall into the liquefaction reactor counter currently to a stream of hot gas which is utilized to dry and preheat the agglomerates as well as deposit catalyst on the agglomerates before they enter the reactor where they are converted to primarily liquid products under hydrogen pressure.
Claims: A method for the hydrogenation of coal in a reactor operating at a pressure substantially greater than atmospheric pressure at elevated temperatures in the presence of a catalyst for converting the coal to hydrocarbon liquids and gases, comprising the steps of preparing an aqueous slurry of coal particulates, a water soluble catalyst and water with the water being in a sufficient amount to effect the dissolution of the catalyst and to provide the slurry with the sufficiently low viscosity to be mechanically pumped, adding an adequate amount of oil to the slurry to form agglomerates of the coal particulates, agitating the slurry to form the agglomerates, mechanically pumping the resulting slurry containing the agglomerates, excess water and unagglomerated solids to a pressure of at least about 1000 psig, separating the agglomerates from excess water and unagglomerated solids, passing the separated agglomerates through a dryer-preheater, contacting the agglomerates in the dryer-preheater with a stream of hot gas flowing countercurrently to the direction of flow of the agglomerates for drying the agglomerates, depositing the catalyst on the agglomerates and preheating the agglomerates prior to introduction thereof into a hydrogenation reactor, and thereafter contacting the coal particulates in the reactor with liquid reaction products and hot hydrogen to effect the hydrogenation of coal particulates at a pressure of at least about 1000 psig and a temperature in a range of about 340 to 450 C.
The method for the hydrogenation of coal ... wherein the sufficient concentration of water provides a coal-to-water slurry containing about 10 to 40 weight percent dry coal, and wherein the reactor pressure is in the range of about 1000 to 3500 psig.
(So, this is a rather high-pressure process, similar in that respect to the original Bergius high-pressure process for direct reactions between Coal and Hydrogen, about which we reported, for one example, in:
West Virginia Coal Association | Bergius 1928 Coal Liquefaction | Research & Development; concerning: "United States Patent 1,669,439 - Process for Distilling and Liquefying Coal; 1928; Inventor: Friedrich Bergius, of Heidelberg, Germany; Abstract: This invention relates to improvements in a correlated process for distilling and liquefying coal. Claims: Process which comprises subjecting coal to distillation treatment whereby there are produced ammonia, coke, tar, a gaseous fraction relatively poor in hydrogen but of high heating value and a gaseous fraction relatively rich in hydrogen, admixing the said tar with coal and subjecting the mixture to liquefaction and hydrogenation treatment with the gaseous fraction relatively rich in hydrogen at elevated temperature and under great pressure whereby there are produced ammonia, oil, and a gas of high heating value, combining the gas of high heating value with said gaseous fraction relatively poor in hydrogen, and separately recovering the said oil".
And, which process was so innovative and so effective, that, as we reported in:
West Virginia Coal Association | CoalTL Wins Nobel Prize - in 1931 | Research & Development;
its inventor, Friedrich Bergius, was awarded the Nobel Prize in Chemistry.
The Bergius process, as we read the specifications, called for quite a lot more pressure in the reactor than does the process of our subject, "United States Patent 4,735,706 - Process and Apparatus for Coal Hydrogenation". And, we figure, that, if they could manage such even more demanding conditions back in the nineteen twenties, we should certainly be able to rather easily achieve the needed pressures of our subject in the modern chemical processing equipment available to us today.)
The method for the hydrogenation of coal ... including the additional step of recycling of excess water separated from the agglomerates for use in the step of preparing the aqueous slurry (and) wherein the step of separating the agglomerates from the unagglomerated solids and excess water comprises conveying the slurry of coal-oil-catalyst agglomerates and water into a volume having screen means therein for retaining the agglomerates while providing for the flow of water and unagglomerated solids through the screen means.
The method for the hydrogenation of coal ... wherein said oil (in which the feed Coal is slurried) is derived from the hydrogenation of coal, wherein said adequate amount of oil is in the range of about 5 to 35 weight percent based on the weight of the dry coal in the slurry, and wherein the agglomerates are in a size range of about 1 to 4 mm.
(The Coal does, as above, have to be crushed rather fine.)
The method for the hydrogenation of coal as claimed in claim 4 wherein the step of passing the agglomerates through the dryer-preheater into the reactor is provided by vertically orienting the dryer-preheater and dropping the agglomerates therethrough into the reactor (and) wherein the hot gas contacting the agglomerates in the dryer-preheater is provided by the stream of gas of primarily hydrogen for heating the agglomerates to a temperature in the range of about 190 to 350 C.
The method for hydrogenation of coal ... wherein up to about 20 mole percent hydrogen sulfide is added to the hot hydrogen in the reactor for effecting the hydrogenation reaction.
(We've previously reported several times that Hydrogen Sulfide, as above, can be made to serve to good effect in Coal hydrogenation processes, as seen, for just one example, in:
West Virginia Coal Association | Exxon Improves Coal Liquefaction with Hydrogen Sulfide | Research & Development; concerning: "United States Patent 4,094,765 - Coal Liquefaction Process; 1978; Assignee: Exxon Research and Engineering Company; Abstract: A coal liquefaction chargestock is first treated with a hydrogen sulfide-containing gas and thereafter subjected to coal liquefaction conditions. A process for the liquefaction of coal, which comprises the steps of: treating a slurry comprising coal and a diluent with a hydrogen sulfide-containing gas".)
Background: The present invention relates generally to a method and apparatus for the hydrogenation or liquefaction of coal, and more particularly to such a method and apparatus capable of continuously converting coal particulates to primarily liquid hydrocarbon products by providing an aqueous pumpable slurry containing coal and a water soluble catalyst, forming agglomerates of the coal with the aid of added oil, separating essentially all the water from the agglomerates by passing the agglomerates through a drainage means followed by a dryer and preheater, and then passing the dried and preheated agglomerates into a reactor where they are hydrogenated.
In continuous direct coal liquefaction processes as previously known, pulverized coal is fed into the process as a slurry formed of coal particles and a solvent provided by recycling a portion of the coal liquefaction product. The coal slurry is usually pressurized by a pump, passed through a preheater and then into a reactor where the coal is converted to liquid and gaseous products under the influence of elevated temperature and hydrogen pressure. ... The maximum solids content of the feed slurry in such previous processes is limited to slightly more than 40 weight percent since with greater solids content the slurry becomes so viscous as to be unpumpable. The use of such relatively large concentrations of solvent with the feed coal is disadvantageous in that it is wasteful of energy since the solvent must be heated to reaction temperature along with the coal and is also wasteful of the interior volume of process equipment in that only about 50 percent or less by volume of the feed slurry consists of coal. Thus, it is desirable to have an alternative method to the conventional coal/solvent slurry for feeding coal to a liquefaction process.
It is also known within the art that an efficient method for introducing catalysts into a coal liquefaction system is through impregnation from solution. The catalysts are often salts of transition metals such as iron, molybdenum, nickel or tin. If water-soluble salts are used, the catalysts may be impregnated from an aqueous solution. Compared to other methods of catalyst addition, impregnated catalysts are efficacious at small concentrations, which is thought to be due to the highly dispersed nature of the catalysts within the coal particles and the proximity of catalysts to reactive sites in the coal. The use of catalyst impregnation in continuous liquefaction processes has been limited to date due to the expense of drying coal after impregnation and prior to charging a coal-solvent slurry to the process.
The direct liquefaction of coal in the presence of large amounts of water is also known in the art (but) to the present time there is no commercially attractive method for liquifying coal that uses an aqueous feed slurry.
Summary: From the foregoing, it can be seen that water provides a satisfactory medium for pumping a feed slurry of coal to a reaction pressure if essentially all the water can be removed prior to introduction of the coal into the reactor. In accordance with the present invention, it has been found that this water removal can be accomplished in part by using oil agglomeration of coal ... . To prepare coal/oil agglomerates, an aqueous slurry of pulverized coal is mixed with a small amount of oil which is typically in the range of about 5 to 35 weight percent of the dry coal. After a suitable period of agitation the coal is formed into agglomerates which have favorable properties for use as a feed to a coal liquefaction process. Mineral matter present in the coal is rejected to the water phase so that the coal-oil agglomerates are concentrated in organic matter.
Coal-oil agglomerates may be prepared in a size range of less than 1 millimeter (mm) to greater than 1 centimeter in diameter. Agglomerates in a size range of about 1 to 4 mm are preferred for use in the present invention. With agglomerates in this size range, most of the water present during agglomerate formation can be removed by a simple draining step. The moisture content of the drained agglomerates is in a range of about 8 to 20 percent by weight of the dry coal in the agglomerates. The concentration of catalyst desired for the coal fed to the reactor can be readily provided by incorporating a water soluble catalyst in the coal slurry used to prepare the agglomerates. The water soluble catalyst adheres to the coal particles when the water is evaporated from the agglomerates before they are fed into the reactor.
In the present invention the only vehicle accompanying the feed coal into the reactor is provided by the binder oil used to form the agglomerates. Because this fraction of oil in the feed coal is so small, the process is thermally efficient for preheating the coal feed. Coal-oil agglomerates that have been drained to a moisture content of about 8 to 20 percent are allowed to free fall into the reactor countercurrent to a stream of hot gas (primarily hydrogen) and introduced into the dryer-preheater. The hot gas dries the agglomerates, leaving the desired concentration of impregnated catalyst. The hot gas also preheats the agglomerates prior to their dropping into the reactor. The heat of reaction of hydrogen with coal in the reactor is used to provide much of the heat necessary to bring the agglomerates up to reaction temperature.
Generally, the practice of the present invention is directed to the method for the hydrogenation of coal at a pressure substantially greater than atmospheric pressure and at elevated temperatures in the presence of a catalyst to convert the coal to hydrocarbon liquids and gases."
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As in our introductory citation of our earlier report concerning Rockwell's "US Patent 4,169,128 - Coal Liquefaction Apparatus", and as we noted in that report, direct hydrogenation processes, though seeming to require a fair amount of energy, appear to provide a continuous, high-productivity means for converting Coal into "hydrocarbon liquids and gases"; and, thus, might make up for the energy costs in terms of efficiency and relative simplicity of design and operation.
In any case, our US Department of Energy found the technology promising enough to sponsor its further development and improvement, as seen in:
"United States Patent: 5015366 - Process and Apparatus for Coal Hydrogenation
Patent US5015366 - Process and apparatus for coal hydrogenation - Google Patents
Date: May, 1991
Inventors: John Reuther, PA, and Theodore Simpson, VA
Assignee: The United States of America
Abstract: In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture is drained of excess water and dried at atmospheric pressure leaving catalyst deposited on the agglomerates. The agglomerates then are fed to an extrusion device where they are formed into a continuous ribbon of extrudate and fed into a hydrogenation reactor at elevated pressure and temperature. The catalytic hydrogenation converts the extrudate primarily to liquid hydrocarbons in the reactor. The liquid drained in recovering the agglomerates is recycled.
Government Interests: The U.S. Government has rights in this invention pursuant to the employee/employer relationship of the inventor to the U.S. Department of Energy at the Pittsburgh Energy Technology Center.
Claims: In a method for processing carbonaceous material containing mineral matter and feeding the carbonaceous material into a hydrogenation reactor operating at an elevated pressure of about 70 to 250 atmospheres and at a temperature in excess of the plastic softening temperature of the carbonaceous material, the method including the steps of providing an aqueous slurry of the carbonaceous material and mineral matter as finely divided particulates with water and water soluble catalyst in sufficient proportions to effect dissolution and dispersion of the catalyst throughout the slurry, mixing a sufficient amount of oil into the slurry to form agglomerates of the finely divided carbonaceous material and oil while leaving the mineral matter essentially as unagglomerated solids; the improvement comprising:
- separating the agglomerates of carbonaceous material from the slurry containing the unagglomerated mineral matter at about atmospheric pressure;
- separating the mineral matter from residual solution containing dissolved catalyst and recycling the residual solution and catalyst to provide aqueous slurry;
- drying the carbonaceous agglomerates at about atmospheric pressure to remove essentially all of the moisture and to deposit solute catalyst onto the agglomerates;
- (and) extruding the agglomerates with deposited catalyst from about atmospheric the agglomerates to the elevated pressure and at a temperature below that at which the carbonaceous material without the added oil enters a plastic condition and feeding the extruded agglomerates into the hydrogenation reactor.
The method ... wherein the carbonaceous material is particulate coal.
Background: The present invention relates generally to a method for the hydrogenation or liquefaction of coal, and more particularly to a method of continuously converting coal particulates to liquid hydrocarbon products.
In U.S. Pat. No. 4,735,706 to the inventor, Ruether, coal-oil agglomerates are prepared in an aqueous slurry and the resulting mixture pumped to reaction pressure where excess water and unagglomerated solids are removed. Sufficient catalyst, previously dissolved in the aqueous solution, remains deposited on the agglomerates entering the liquefaction reactor. Although this process is effective and useful it has the disadvantage of requiring dewatering and drying at elevated pressures which can substantially increase process equipment cost.
(This invention, thus, represents an efficiency improvement over the Coal hydrogenation process of our initial subject, "US Patent 4,735,706 - Process and Apparatus for Coal Hydrogenation", as above.)
Summary: In accordance with the present invention a method for introducing carbonaceous material at elevated pressure and temperature into a hydrogenation reactor is provided. The method involves providing an aqueous slurry of the carbonaceous material as finely divided particulates with water and water soluble catalyst in sufficient proportions to effect dissolution and dispersion of the catalyst throughout the slurry. A sufficient amount of oil is mixed into the slurry to form agglomerates of the finely divided carbonaceous material and the agglomerates are separated at atmospheric pressure from the excess aqueous solution and unagglomerated solids. The agglomerates are then dried to remove essentially all of the moisture and to deposit solute catalyst onto the agglomerates. The coal-oil agglomerates as thus provided with deposited catalyst are extruded as a continuous ribbon into the hydrogenation reactor at elevated pressure and elevated temperature, but with the extrusion temperature below that at which the carbonaceous material without the added oil enters a plastic condition.
The catalyst utilized is a water-soluble salt of a transition metal. For example, materials such as ammonium tetramolybdate, ammonium paramolybdate, ferrous sulfate heptahydrate, ferrous nitrate hexahydrate, and nickel sulfate and its hydrates are satisfactory for the practice of the present invention. The concentration of molybdenum-containing salts found to be sufficient for effecting desirable coal-to-liquid conversions in a reactor is in the range of about 0.005 to 0.5 weight percent molybdenum expressed as a percentage of dry coal in the agglomerates fed into the reactor. Preferably this range is 0.01 to 0.25 weight percent molybdenum. For iron-containing salts, the concentration is 0.2 to 2.0 weight percent iron. However, any water-soluble catalytic material known in the art may be satisfactorily used in the practice of the present invention. Typically, the catalyst will be in an amount less than 2 percent by weight of the dry coal.
(The catalysts, thus, aren't made of stuff that's too-expensive; and, since they aren't used up in the process, or combined into the product, they should be recoverable and recyclable.)
Hydrogen is fed to (the) reactor ... after being compressed to reactor pressure ... and heated. Additional heat beyond that generated by the exothermic liquefaction reaction is required to support the hydroliquefaction reaction. This heat is supplied via the feed hydrogen which can be heated as required for thermal balance to a temperature up to 450 C.
(The reactor) can be of a known, slurry bubble column design with the extrudate entering at the bottom and the liquefaction products and unreacted solids withdrawn ... near the top. The product of liquid and unreacted solids can be subjected to any further treatment as desired.
The present invention provides several advantages over previously employed processes for conducting direct liquefaction of coal."
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If, as our own US Government concludes, they have developed "advantages" in "processes for (the) direct liquefaction of" our abundant, domestic US "coal", in order to synthesize the "liquid hydrocarbon products" we have been mortgaging our grandchildren's futures to OPEC and fighting hugely expensive foreign wars to keep ourselves supplied with, why, we must ask, hasn't our US Government taken the additional steps of, first, telling it's US citizens all about it, and, then, helping it's US citizens, many of whom could use the jobs such an effort would create, to start mining more of that Coal and, then, to start converting that Coal into those "liquid hydrocarbon products", products that would, while creating more US jobs, choke off the flow of our money to overseas destinations, where too much of that money already has been used to finance, let's be honest about it, military conflicts and terrorism?
We didn't compose and summarize that question very well.
That doesn't make it any less deserving of an answer.