We enclose in this dispatch report of an intriguing use for Sulfur Dioxide, SO2, which can be scrubbed, in greater or lesser quantities, depending on the grade of Coal used, from the exhaust gases of some Coal-fired power plants.
Maybe we don't like to talk about the supposed pollutants arising from our productive and essential uses of Coal, but, when, as in the case of CO2, and the technologies related to it's productive recycling, as seen in:
USDOE 1976 Atmospheric CO2 to Methanol | Research & Development; which concerns: "United States Patent 3,959,094 - Electrolytic Synthesis of Methanol from CO2; 1976; Assignee: The USA; A method and system for synthesizing methanol from the CO2 in air using electric power"; and:
USDOE Converts 100% of Power Plant CO2 to Methanol | Research & Development; concerning: "The Carnol Process System for CO2 Mitigation and Methanol Production";
we learn that those supposed pollutants are actually raw materials of potentially great value, why not?
Again, though, Sulfur Dioxide is the wrongly-vilified substance we address herein.
And, as you will see, it can provide anyone who has it, and who is willing to take advantage of it's attributes, both a product needed to convert Coal and to recycle Carbon Dioxide into valuable hydrocarbons, along with what you will also see to be described as the "largest-volume industrial chemical produced in the world".
Comment follows excerpts from the initial link in this dispatch to:
"United States Patent 4,244,794 - Hydrogen Production by the Decomposition of Water
Date: January, 1981
Inventors: Charles Hollabaugh and Melvin Bowman, Los Alamos, NM
Assignee: The United States of America
Abstract: How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolytical-thermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO2 react in (an) electrolyzer ... so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode.
Background and Field: This invention relates generally to the production of hydrogen gas from water and in particular relates to a sulfuric acid process for producing hydrogen. It is a result of a contract with the Department of Energy.
Claims: A process for producing hydrogen comprising:
(1) passing an electric current from a cathode to an anode through water containing sulfur dioxide so as to produce hydrogen gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid at the anode, thus producing an aqueous solution of sulfuric acid;
(2) separating said hydrogen gas from said aqueous solution of sulfuric acid.
Background and Field: In recent years, much effort has been directed toward development of an economically viable process for the production of hydrogen by the decomposition of water. Investigation of the use of a sulfuric acid cycle for producing hydrogen has been a very popular area of research because of the favorable thermodynamic considerations of such a cycle and because of the fact that methods of handling sulfuric acid have long been known.
It is an object of this invention to produce hydrogen gas from water by a sulfuric acid process employing electrolysis and thermo-chemical decomposition.
It is a further object of this invention to produce concentrated sulfuric acid, as well as hydrogen gas.
Summary: According to the invention, hydrogen gas is produced from water in a process comprising:
passing an electric current from a cathode to an anode through water containing sulfur dioxide (SO2) so as to produce hydrogen (H2) gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid (H2SO4) at the anode;
(and) separating the produced hydrogen gas from the aqueous solution of sulfuric acid".
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We close our excerpts there so that we can emphasize a few things.
First of all, equations and reaction summaries, provided by our USDOE in the full Disclosure, demonstrate that: producing Hydrogen by the electrolysis of a Water solution of Sulfur Dioxide, SO2, reduces the energy required, relative to producing Hydrogen by the electrolysis of Water alone, by fully 80%.
That, we submit, is dramatic. The USDOE itself suggests that environmental, i.e., Solar, energy alone would be sufficient to drive the entire process.
And, much of the energy required by that total process is utilized in the conversion of product Sulfuric Acid back into SO2.
Keep in mind that a, perhaps dilute, solution of SO2 in Water is what we could get by scrubbing a Coal-fired power plant's exhaust fumes.
We could thus reduce the energy requirements, and the costs, of our "United States Patent 4,244,794" process, by substituting fresh solutions of SO2 obtained from such power plant exhaust gas scrubbers, instead of by reprocessing the by-product Sulfuric Acid, H2SO4.
And, in fact, since, as seen in:
Sulfuric Acid, which relates that: "Sulfuric acid is ... the largest-volume industrial chemical produced in the world, consumption of sulfuric acid is often used to monitor a country's degree of industrialization. Agricultural fertilizers represent the largest single application for sulfuric acid (65%). Other uses include production of dyes, alcohols, plastics, rubber, ether, glue, film, explosives, drugs, paints, food containers, wood preservatives, soaps and detergents, pharmaceutical products, petroleum products, pulp and paper";
and, in:
Chemical of the Week -- Sulfuric Acid, wherein we're told: "Sulfuric acid is the product of the U.S. chemical industry produced in largest quantity in terms of mass. About 40 million tons are produced annually";
a large and ready commercial market exists for H2SO4, if we were to sell what of it was produced by our subject "United States Patent 4,244,794" into that market, instead of reconverting it back into Sulfur Dioxide, those sales would help to lower even further the actual cost of the primary product generated so efficiently by this patented technique: Hydrogen.
Which inexpensive Hydrogen is actually the point of our little thesis, since, once we have it, generated so efficiently for us, via the process herein of "United States Patent 4,244,794", from Coal-fired power plant stack gas scrubbing water, we can, as in:
NASA Rocket Fuel from CO2 | Research & Development; which tells us to: " Mix some carbon dioxide (CO2) with hydrogen (H), then heat the mixture to produce CH4 and H20 -- methane and water";
use that Hydrogen to recycle Carbon Dioxide into "synthetic" Methane, a substitute natural gas. Or, as in:
Germany Invents WVU Coal Liquefaction Solvent - in 1926 | Research & Development; concerning: "United States Patent 1,582,310 - Hydrogenation of Naphthalene; 1926; The ... hydrogenation of commercial naphthalene (using Hydrogen, to form) tetrahydronaphthalene", aka "Tetralin";
we can use the Hydrogen to hydrogenate the primary Coal, or Coke Oven, tar, "naphthalene", to form "Tetralin", which, as in:
WVU Hydrogenates Coal Tar | Research & Development; wherein is reported: "Hydrogenation of Naphthalene and Coal Tar Distillate; West Virginia University, 2009; The hydrogenation of naphthalene (to form) tetralin (for use in) the conversion of coal to ... gasoline, diesel, kerosene, etc.";
can then be used to directly convert Coal into a full range of liquid hydrocarbon fuels.