United States Patent: 7776150

We've documented many, many times that our varied and productive uses of Coal lead to the co-production of compounds and materials that we could, and should, begin to view and treat as valuable by-products, rather than as pollutants we must somehow, at great unproductive expense, find some way to just, in some way satisfactory to the seeming legions opposed to Coal, dispose of.

For just two examples, without referencing any of our past reports, it now seems incontrovertible that Coal fly ash can be utilized to good economic effect in the making of cement and concrete; and, that, Carbon Dioxide can be recycled in the synthesis of hydrocarbon fuels.

Another by-product of Coal use, which we've touched on only once or twice, is the "sludge" generated by at least some types of "Flue Gas Desulphurization", "FGD", devices, which, by regulation, are now being installed on all new Coal-fired electric power plants, and which have been retrofitted on most existing ones.

More, in general, can be learned about the various FGD technologies that are available, from the US EPA, via the link:

http://www.epa.gov/ttn/catc/dir1/ffdg.pdf: "EPA-452/F-03-034; Air Pollution Control Fact Sheet: Flue Gas Desulfurization (FGD) - Wet, Spray Dry and Dry Scrubbers";

wherein we're told that, for various reasons, "85%" of the FGD Scrubbers are of the "Wet" variety, and, because of its low expense, Limestone is used as the preferred absorbent material.

The EPA itself makes note of the fact that is the core of our report herein:

Such "wet" stack gas scrubbers, utilizing limestone as the reactive reagent for desulfurization, result in the production of "synthetic" Gypsum, which does have commercially-valuable industrial uses, as we will further illustrate.

That fact is so well-recognized, in fact, that processes have been developed for an initial processing of FGD sludge, to convert it into a form that's easier to handle and transport, as seen in excerpts from the initial link in this dispatch to:

"United States Patent 7,776,150 - Process and Apparatus for Handling Synthetic Gypsum

Date: August, 2010

Inventors: Eberhard Neumann, NC, and Claus Bech, SC

Assignees: Koppern Equipment Company, NC, and Giant Cement Company, SC

Abstract: Method and apparatus for converting wet synthetic gypsum from a flue desulphurization process (FGD) to easily handled and metered briquettes by mixing a hydraulic additive such as by-pass dust from a cement kiln with synthetic gypsum and allowing the heat from the resulting hydraulic reaction to reduce the water content of the mixture to a formable consistency without adding external heat to the mixture as it is formed into briquettes.

(Don't be discouraged by the apparent need for "by-pass dust from a cement kiln" if you're thinking in terms of utilizing FGD Gypsum at a Coal-fired power plant in order to make the "briquettes". As can be learned via:

http://www.concretethinker.com/Content/Upload%5C437.pdfsuch "by-pass dust" consists primarily of limestone dust, calcium carbonate, that escaped being calcined, and very fine sand, or quartz dust, silicon oxide, which is a major constituent of Coal-fired power plant fly ash.

There would be no trouble, or great expense, entailed by getting either for use in this process.)

Claims: A process for preparing and handling synthetic gypsum for cement production and like uses comprising the steps of: a) providing synthetic gypsum in a form consisting essentially of gypsum having a paste-like consistency; b) adding sufficient hydraulic active additive to said gypsum to initiate a hydraulic exothermic reaction to evaporate water in said gypsum; c) allowing said reaction to continue until the surface water on the mixture has been reduced to a level at which the mixture is formable; d) compacting said gypsum when the water content has been sufficiently reduced to allow stable compaction of said gypsum; and e) storing said compacted gypsum for future use or using it in a cement making process immediately.

Summary: This invention relates to a process and apparatus for handling synthetic gypsum so that it may be more effectively handled, stored, and metered in cement production and similar processes."

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Note that the primary use for FGD Gypsum specified by "United States Patent 7,776,150" is in "cement production", and, keep in mind that would be in addition to the use of other Coal residuals, i.e., Fly Ash, in the making of cement and concrete, both as one of the primary reactants in the chemical synthesis of Portland cement and as an aggregate for cement, once it is made, to form concrete. Two examples of our earlier reportage on such potentials are accessible via:

Coal Ash Can Reduce Construction Costs | Research & Development; and:

Consol Converts Coal Ash to Concrete Aggregate | Research & Development.

And, more are to follow.

However, more about the use of FGD synthetic gypsum in the making of cement can be learned via:

Lehigh Cement Company- About Lehigh and Lehigh Cement Company-Education; wherein we're told:

"Lehigh Cement Company was founded in 1897 in Allentown, Pennsylvania. Over the years, through a visionary policy of acquisitions, equipment modernization and productivity improvements, Lehigh Cement Company and its related companies have become leading suppliers of cements and construction materials in the United States and Canada."

And, that:

"Gypsum is a mineral (specifically, CaSO4…2H2O - hydrated calcium sulfate). Many Lehigh plants use gypsum that is quarried from a major reserve in Nova Scotia ... . Gypsum is a critical ingredient that helps to control the setting time of the cement when it is mixed into concrete."

And, thus, we can make a "critical ingredient" for cement making from Coal-fired power plant FGD devices, a "critical ingredient" that otherwise, for the most part, would have to be imported.

But, in addition to it's "critical" importance in cement-making, Gypsum, including FGD Gypsum, does have other important commercial applications, as explained by the United States Gypsum Company, via:

http://www.usg.com/rc/brochures/industrial-plasters-cements/industrial-plasters-gypsum-cements-brochure-en-IG504.pdf;

"From the United States Gypsum Company; Industrial Plasters and Gypsum Cements: Versatile Products for Countless Industrial Applications"; and:

http://library.acaa-usa.org/2-FGD_Gypsum_in_Wallboard_and_Other_Products.pdf;

"FGD Gypsum in Wallboard and Other Products; United States Gypsum Company; 2007.

Gypsum Key Commercial Properties: Safe and non-toxic mineral; Common by-product from sulfur processing (i.e.,) FGD Gypsum.

Can be calcined at low temperatures (and) Provides fire resistance (and) Produces a low cost inorganic binder.

FGD Gypsum in Wallboard: 63% of all FGD Gypsum produced is recovered into wallboard (and over) 27% of wallboard (is) produced from FGD Gypsum

12 new wallboard lines (have been) built to handle FGD Gypsum (and) 4 new lines (have been) announced.

Wallboard plants (are now) located near major markets or near low cost mines (and, the) East Coast (is)supplied from Nova Scotia (and, the) West Coast supplied from Mexico.

(In other words, again, we have the opportunity to replace imported natural Gypsum with domestic synthetic Flue Gas Desulfurization, FGD, Gypsum; and, there is a large, established market for it. According to graphics supplied by US Gypsum in the full presentation, there are already a dozen wallboard plants that do, or can, utilize synthetic FGD Gypsum; but, the potential exists for consumption of FGD Gypsum to quadruple, and to do so rapidly, since there are no technical barriers to its use.)

Other Industrial Products (for) FGD Gypsum: Plasters; Fillers (and) Gypsum Fiber Board (which consumes) over 200,000 tons per year of FGD Gypsum".

And, again, US Gypsum goes on to identify the definite potential for large future growth in the use of FGD Gypsum in the markets specified immediately above, all of which are in addition to the use of FGD Gypsum in the making of Portland-type cement, i,e, "cement production", as specified in our primary subject, "United States Patent 7,776,150 - Process and Apparatus for Handling Synthetic Gypsum".

All, of which suggests to us that we have yet another opportunity in United States Coal Country, in addition to the potentials for converting some of our abundant Coal into liquid hydrocarbon transportation fuels; for recycling our effluent Carbon Dioxide into hydrocarbons; and, for utilizing our Coal Fly Ash in the making of cement and concrete; to more fully employ yet another largely unappreciated, though inherently valuable, byproduct arising from one of our traditional uses of Coal, and, thus, in the course of improving our environment, provide even more productive employment for the current citizens of United States Coal Country

and secure a more prosperous future for the children and grandchildren of those citizens.

Is there some reason we don't want to know about any of those potentials, or, to start exploiting them?


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