We know that our headline, i.e., "California Magic Acid", might, for those among us old enough to have once worn flowers in our hair, conjure up some colorful images that seem wildly incongruent with that of the black bedrock of our reportage, Coal; but, bear with us as we attempt to explain.
And, we beg your patience.
We've previously alluded to our varied personal insufficiencies and disabilities, which sadly limit our capacities both to personally understand the technicalities and to explain them; and, the defection by our more technically-competent advisors, who finally had their fill of being ignored.
One among our loyal number, though, recalls that when you're manning the kitchen of a Joy 12 continuous miner and run into a hard old sand channel, sometimes all you can do is keep tramming, keep the head turning, and keep changing bits, until you hole through.
So, we're going to take a crack at this. The cut might be a little raggedy, but we'll at least get her loaded out.
Please recall that we have many times documented the use of "Hydrogen Donors" in both Coal liquefaction and Carbon Dioxide recycling technologies of various sorts.
One example of our past reportage on that topic would include:
West Virginia Coal Association | WVU Hydrogenates Coal Tar | Research & Development; concerning the: "Hydrogenation of Naphthalene and Coal Tar Distillate over Ni/Mo/Al2O3 Catalyst; Abhijit Bhagavatula; Thesis submitted to the College of Engineering and Mineral Resources at West Virginia University in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering; Department of Chemical Engineering; Morgantown, West Virginia. 2009";
in which it's explained that, in simplistic terms, elemental Hydrogen can be "loaded" into some specific types of Coal tars; and, those thus-hydrogenated Coal liquids can be made to transfer, or "donate" their Hydrogen to raw Coal, thereby liquefying the Coal and converting it into more liquid hydrocarbons.
Another example of Hydrogen transfer, or donation, is seen in:
West Virginia Coal Association | Penn State Solar CO2 + H2O = Methane | Research & Development; concerning: "High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels; Oomman K. Varghese, Maggie Paulose, Thomas J. LaTempa, and Craig A. Grimes; The Pennsylvania State University; 2009; Efficient solar conversion of carbon dioxide and water vapor to methane";
wherein, again in simplistic terms, sunlight, in combination with catalysis, is harnessed to drive the transfer of Hydrogen, from H2O, to the Carbon from CO2.
A further example is seen in:
West Virginia Coal Association | Exxon Multi-Stage Hydrogen Donor Coal Liquefaction | Research & Development; concerning: "United States Patent 4,189,371 - Multiple-stage Hydrogen-donor Coal Liquefaction Process; 1980; Exxon Research and Engineering; Abstract: An increased yield of hydrogenated liquid product is obtained from coal by treating the feed coal with a hydrogen-donor solvent and hydrogen-containing gas ... . Claims: A multiple-stage hydrogen-donor liquefaction process for producing liquid hydrocarbons from coal";
wherein a presence and pressure of molecular, elemental Hydrogen is maintained in a reaction space, and where a material serving as a Hydrogen donor actually just facilitates the transfer of available free Hydrogen atoms into chemical bondage with Carbon atoms derived from Coal.
In point of fact, we are all, perhaps unknowingly, familiar with Hydrogen transfer reactions.
They are, in a way, at the heart of what happens when acids - like vinegar, or sulfuric acid, H2SO4, - start to corrode or react with something, a metal or a "base" compound.
Other things are going on in such reactions, of course, and, sometimes, the Hydrogen isn't donated or transferred to another compound, but, instead, just liberated.
And, another thing to keep in mind is that atomic Hydrogen is pretty simple stuff, with an atom of Hydrogen consisting of just one electron and one proton. That fact sometimes leads to the use of confusing or distracting terminology, when what are essentially Hydrogen transfer reactions are described or labeled in the literature concerning Coal and Carbon Dioxide hydrogenation.
That, too, is something we'll address in future reports; but, herein, we wanted to begin reintroducing the use of what have become known as "super acids", as agents of Hydrogen transfer in Coal hydrogenation processes, since such super acid-based conversion technologies do offer the potentials of improved product control and process efficiencies.
And, "super acids" weren't always known by that name.
A scientist who should by now be familiar to you, from our report, as one example out of many, concerning:
West Virginia Coal Association | California Recycles Coal Power Plant Carbon Dioxide | Research & Development; which included, in part, information about: "US Patent Application 0110086928 - Eliminating the Carbon Footprint of Human Activities; 2011; George Olah and Surya Prakash, CA (we the University of Southern California will be the ultimate named Assignee of Rights.) Abstract: A method for neutralizing or reducing the carbon footprint from carbon dioxide emissions due to human activities related to the combustion or use of carbon containing fuels. This method includes an initial step of capturing carbon dioxide and then chemically recycling it to form and provide a permanent inexhaustible supply of carbon containing fuels";
once referred to them as "magic acids", when he first began to study them and their potentials for application in Carbon and Hydrocarbon conversion processes, as explained in:
Magic acid - Wikipedia, the free encyclopedia; which relates, that "Magic acid (FSO3H-SbF5), is a superacid (and is a) conjugate Bronsted-Lewis superacid system (that) was developed in the 1960s by the George Olah lab at Case Western University in Cleveland, and has been used to stabilize carbocations and hypercoordinated carbonium ions in liquid media. Magic Acid and other superacids are also used to catalyze isomerization of saturated hydrocarbons, and have been shown to protonate even weak bases, including methane, xenon, halogens, and molecular hydrogen."
Olah, by the way, paid his dues in Cleveland, Ohio, at Case Western University, before moving to the balmier climes of Southern California, where he won his Nobel Prize for further work on the above-noted oddity, "carbocations", which we explained in our previous report, as linked above, concerning "United States Patent Application 0110086928 - Eliminating the Carbon Footprint of Human Activities".
So intriguing was Olah's work with "magic acid", and, more broadly, "superacids", that our own USDOE hired Olah to further develop their use as Hydrogen donors, Hydrogen transfer agents, for the hydrogenation and liquefaction of Coal, as we documented in our report of:
West Virginia Coal Association | USDOE Pays California to Liquefy Coal | Research & Development; concerning: "Superacid Catalyzed Coal Conversion Chemistry; Final Technical Report; USDOE Contract Number: DE-FG22-83PC60810; 1986; Author: George Olah; Organization: University of Southern California; The basis of our studies was a novel, low temperature, mild coal conversion process developed in our laboratory. It involves the use of a superacidic system consisting of HF and BF, in the presence of hydrogen and/or a hydrogen donor solvent. The goal of the project was to study model systems to understand the basic chemistry involved and to provide a possible effective pretreatment of coal which significantly improves liquefaction-depolymerization under mild conditions. The conversion process operates at relatively low temperatures ... and pressures and uses an easily recyclable, stable superacid catalyst. It consequently offers an attractive alternative to currently available processes".
And, what might have attracted our USDOE's interest in Olah, and his "recyclable, stable superacid catalyst" for "low temperature, mild coal conversion", is the confirmation of the technology's validity which is the subject of our report herein, as seen in excerpts from the initial link above to:
"United States Patent 4,394,247 - Liquefaction of Coals Using Recyclable Superacid Catalyst
Date: July, 1983
Inventor: George Olah, Beverly Hills, CA
Abstract: This invention discloses a process for the liquefaction of coals and other predominantly hydrocarbonaceous materials by treating the same with a superacidic catalyst system consisting of anhydrous hydrogen fluoride and boron trifluoride in the presence of super-atmospheric hydrogen.
Claims: A process for the liquefaction of coals or other predominantly hydrocarbonaceous materials by treatment thereof with hydrogen gas under superatmospheric pressure of 25-150 atmospheres at temperatures of 50.-250C. in the presence of a superacidic system comprising anhydrous hydrogen fluoride and boron trifluoride, present in a mole ratio of about 0.5 to 2 to 1.
The process ... in which the temperatures used are between about 100 and 250C and the pressures used are between about 35 to 75 atmospheres.
(Rightly or wrongly, we tend to see this as a variation of other direct Coal hydrogenation technologies, such as those described, for just two examples, in:
California Rocket Scientists Liquefy Coal | Research & Development; concerning: "United States Patent 4,243,509 - Coal Hydrogenation; 1981; Rockwell International Corporation, CA; Abstract: Disclosure is made of a method and apparatus for reacting carbonaceous material such as pulverized coal with heated hydrogen to form hydrocarbon gases and liquids suitable for conversion to fuels"; and, the earlier:
West Virginia Coal Association | West Virginia Hydrocracks Coal Liquids with Brute Force | Research & Development; concerning: "United States Patent 2,913,397 - Hydrogenolysis of Coal Hydrogenation Products; 1959; Inventors: James Murray, et. al., South Charleston and Nitro, WV; Assignee: Union Carbide Corporation; Abstract: This application relates to chemical processes. More particularly it relates to an improvement in processes for obtaining chemicals from coal. Various processes have been proposed for the purpose of obtaining chemicals from coal. Among the most promising of these have been those involving coal hydrogenation. Broadly speaking, such processes encompass contacting coal with hydrogen in such a manner that the coal is converted to gaseous and liquid products, plus a pitch residue, and in most instances a small amount of ash. In the process of the invention the material to be processed, as for example the liquid product of coal hydrogenation, is subjected to reaction with hydrogen at elevated temperatures and under increased pressure, in the absence of a catalyst, for the purpose of achieving the desired hydrogenolysis and consequent simplification of the product";
with the difference being that Olah's "super acid" facilitates the transfer of available gaseous Hydrogen into chemical recombination with the available Carbon in a way that reduces the needed temperatures and pressures, and, thus, the operating costs.)
The process ... further including the step of recovering and recycling the superacidic system.
The process ... further including the step of using the hydrogen sulfide produced as a by-product of the process to form hydrogen gas to be utilized in the process.
(Regarding the above claim, we have previously documented, as in:
Florida Hydrogen and Sulfur from H2S | Research & Development; concerning: "United States Patent 6,572,829 - Photocatalytic Process for Decomposing Hydrogen Sulfide; 2003; University of Central Florida; Abstract: System for separating hydrogen and sulfur from hydrogen sulfide (H2S) gas produced from oil and gas waste streams";
that waste Hydrogen Sulfide can serve as a source of Hydrogen; and, that, as in:
West Virginia Coal Association | Allied Chemical Liquefies Coal with CO & H2S | Research & Development; concerning: "United States Patent 4,235,699 - Solubilization of Coal with Hydrogen Sulfide and Carbon Monoxide; 1980; Assignee: Allied Chemical Corporation; Abstract: Conversion of coal to products soluble in common solvents and conversion of coal tar to products of lower molecular weight, effected in liquid or fused reaction medium using a hydrogenating reactant, are carried out employing hydrogen sulfide and carbon monoxide as the sole or major hydrogenating reactant, without need of elemental hydrogen or a hydrogen donor solvent";
it can be used directly as an agent of Coal hydrogenation.)
A process for the liquefaction of coals or other predominantly hydrocarbonaceous materials comprising the steps of (i) treatment thereof with a superacidic system comprising hydrogen fluoride and boron trifluroide, present in a mole ratio of about 0.5 to 2 to 1, to effect depolymerization followed by (ii) conventional catalytic hydrogenation of the depolymerized products prepared in step (i).
Background and Field: This invention discloses a process for the liquefaction of coals and other predominantly hydrocarbonaceous materials by treating the same with a superacidic catalyst system consisting of anhydrous hydrogen fluoride and boron trifluoride in the presence of super-atmospheric hydrogen.
Coal liquefaction is of major significance as an alternative synthetic fuel source.
(Well, it should be, even if, 30 years after a Nobel Prize winner said so, it still isn't.)
The conversion of coal into liquid (as well as gaseous) hydrocarbons according to existing technology can be carried out either by direct hydrogenation or through prior conversion to synthesis gas followed by Fisher-Tropsch synthesis. The existing processes are based upon technology developed in Germany during the 1920's employing improved engineering techniques.
Hydrogenation of coals producing liquefied products generally follows two main courses: solvent assisted hydrogenation at 300 to 400C and at 1000-4000 psi or higher temperature flash pyrolysis (600 to 1000C), either at ambient hydrogen pressure or hydrogen pressure up to 1500 psi. The solvent assisted liquefaction has the virtue of being able to obtain a high yield coal conversion to liquid products of relatively low molecular weight.
The use of catalysts in coal liquefaction processes causes, in general, significant difficulties. Coal is a solid material with very limited solubility in most common solvents (organic or inorganic). Thus, a major difficulty or problem in transforming coal catalytically is finding a means to bring hydrogen gas in proper contact with the coal.
This fact obviously causes significant and as yet unresolved problems, if a solid catalyst is used.
Even when employing a very fine mesh coal (mesh size 100.mu.), there is little surface contact. Also, the organic moiety of coals is a cross-linked polymeric material, which can only be partially dissolved or swelled by organic solvents. Thus, a homogeneous catalyst should also be preferentially soluble and compatible with solvents used or the reaction conditions should be such to allow the catalyst to make molecular contact with the large organic cross-linked molecules of coals. Further, the large polyaromatic polynuclear coal backbone must be depolymerized during the process to allow the formation of hydrogenated lower molecular weight hydrocarbons.
Summary: The present invention describes an effective, new economical process to liquefy coal or other predominantly hydrocarbonaceous materials to hydrocarbons utilizing superacid catalyzed depolymerization/
Recyclable anhydrous hydrogen fluoride and boron trifluoride provide both a suitable reaction medium, as well as a very effective catalytic system to allow the depolymerization-hydrogenation of coals under mild conditions, to form liquid hydrocarbons with the co-formation of smaller amounts of gaseous hydrocarbons.
The process is efficient and can be carried out under surprisingly mild conditions.
It is a significant aspect of my invention that the hydrogen fluoride-boron trifluoride superacid medium is completely recoverable and recyclable. This is partly due to the high volatility of the system. Hydrogen fluoride has an atmospheric boiling point 20C and boron trifluoride has an atmospheric boiling point -101C. Further, complexes of boron trifluoride with water, hydrogen sulfide or various other nucleophilic donors present in coal can be readily decomposed, allowing the regeneration of boron trifluoride by thermal or acid treatment. Due to the extremely high redox potential of hydrogen fluoride and boron trifluoride, there are no oxidation-reduction processes taking place. Thus, there is no loss of the superacidic reaction medium, allowing economical conversion of coal under the exceedingly mild conditions.
Residual moisture in the coals may be removed by dehydration by boron trifluoride in the form of stable hydrate. The hydrate can be readily regenerated by heat treatment or with oleum or sulfur trioxide, liberating boron trifluoride gas. There is thus no significant loss of the acid system in the process. The acid system also acts as an advantageous reaction medium in conjunction with hydrocarbon oil for the process, allowing good contact and providing suitable continuously renewed active cationic sites on the coal surface to maintain the hydrogenation reaction.
The conversion reaction can be carried out at temperatures between 50 and 250C, preferentially between 100 and 175C., at pressures ranging from 25 to 150 atmospheres, preferably between 35 to 75 atmospheres.
Coal, after suitable drying and pulverization, is fed by slurrying with a hydrocarbon oil, particularly partial recycling of the products obtained, into a reactor containing hydrogen fluoride, which is then subsequently pressurized with the boron trifluoride and hydrogen, and heated to the required reaction temperature for suitable periods of time ranging from 1 to 24 hours, preferably from 2 to 6 hours, to achieve hydroliquefaction.
After completed conversion, the acid system is removed by depressurization, separated into its components and, after separation from any gaseous hydrocarbons (particularly methane and ethane), is recycled. The converted coal is treated in a conventional way, distilling any coal oils formed, with subsequent refining.
A further significant aspect of the present invention is the insensitivity of the superacidic system to high levels of sulfur and other impurities, allowing the utilization of a wide variety of coals, even of low grades with high levels of these impurities, which are detrimental in other catalytic hydrogenation processes."
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There is a bit, quite a bit, more to it, of course.
And, it does require a supply of free Hydrogen for the "superacid" catalysts, as identified and specified by Olah, to work with.
As we've documented, for just one example, in:
West Virginia Coal Association | Germany & Pennsylvania Hydrogen from Hydropower | Research & Development; concerning, in part: "United States Patent 6,864,596 - Hydrogen Production from Hydro Power; 2005; Voith Siemens Hydropower Generation GmbH and Incorporated, Germany and York, PA;
Abstract: A turbine installation configured for large scale hydrogen production includes a foundation structure separating an upper elevation headwater from a lower elevation tailwater";
we have some intriguing opportunities in the parts of US Coal Country blessed with both hills and streams to generate a little sustainable, economical Hydrogen.
Olah himself, in the full Disclosure, though not represented in our excerpts, suggests reclaiming Hydrogen from any co-produced Hydrogen Sulfide, as in our above-cited report concerning the University of Central Florida's: "United States Patent 6,572,829 - Photocatalytic Process for Decomposing Hydrogen Sulfide".
And, although our read of "United States Patent 4,394,247 - Liquefaction of Coals Using Recyclable Superacid Catalyst" suggests that there won't be much, if any, carbonaceous residues remaining after the bulk of the Coal is converted into "liquid hydrocarbons (and) smaller amounts of gaseous hydrocarbons", if there are, then a process such as that disclosed in our report of:
Consol Low-Cost Hydrogen from CoalTL Residue | Research & Development; concerning: "United States Patent 3,115,394 - Process for the Production of Hydrogen; 1963; Assignee: Consolidation Coal Company, Pittsburgh; Abstract: This invention relates to a process for the production of hydrogen. More particularly, this invention relates to a process for the production of high-purity hydrogen from carbonaceous solids (and) our new process (can be) applied to the hydrocarbonaceous solid residues obtained by the low temperature distillation or carbonization of hydrocarbonaceous solid fuels such as the high volatile bituminous coal found in the Pittsburgh Seam";
could be applied to those residues to generate even more Hydrogen.
In any case, the energy conserved through the milder conditions required by Olah's Coal conversion process herein could well afford sufficient savings, relative to other direct Coal hydrogenation technologies, to more than offset the expense of providing additional Hydrogen.
That, especially, when, again as study of the full Disclosure will reveal, the super acid catalysts aren't consumed within the process, but are regenerated and recycled for reuse as an integral step of the total system.
We will do our best to better explain the complexities of this type of relatively low energy demand Coal hydrogenation and conversion technology as we go along.
And, go along we will, since Olah's establishment of the technical processes disclosed herein led to rather extensive development of closely-related, derivative Coal conversion technologies by major components of the petroleum industry, all seeking to take advantage of this direct and efficient method for the "economical conversion of coal under the exceedingly mild conditions" into "liquid hydrocarbons" suitable for "subsequent refining", and "smaller amounts of gaseous hydrocarbons".