United States Patent: 6755901

As we have begun to document, the Fly Ash byproduct of Coal-fired power generation can be employed in a number of very productive ways, as can, as we've documented, for one instance, in:

Exxon Converts Coal Conversion Residues to Cement | Research & Development; concerning: "United States Patent 4,260,421 - Cement Production from Coal Conversion Residues; 1981; Exxon Research and Engineering Company: Abstract: Cement is produced by feeding residue solids containing carbonaceous material and ash constituents obtained from converting a carbonaceous feed material into liquids and/or gases into a cement-making zone and burning the carbon in the residue solids to supply at least a portion of the energy required to convert the solids into cement";

the solid mineral residues resulting from our conversion of the Carbon content in Coal into hydrocarbons..

We've reported, and will continue to report, that Fly Ash can, in fact, be seen and treated as a rich source of metal ores, especially ores of Aluminum, Iron and Titanium; and, others, as well.

However, one use for Coal Ash that has been long-established, and, which consumes a surprisingly large amount of Ash, but could consume much more, is as a raw material in the making of traditional "Portland" cement, or substitutes for Portland cement, and, subsequently, in the further making of concrete.

Such Ash-based, or Ash-supplemented, cement and concrete, according to all our research thus far, meets or exceeds, or can be made to meet or exceed, all applicable and established standards and specifications.

More about such potentials, pending our further reports on the matter, can be learned from several of the many sources included and accessible within our earlier report concerning:

The Coal Combustion Byproducts Recycling Consortium | Research & Development; which contains links to other references, such as:

05-CBRC-M20: "New Technology Based Approach to Advance Higher Volume Fly ash Concrete with Acceptable Performance; The 2004 fly ash survey conducted by the American Coal Ash Association (ACAA) states that out of the 70 million tons of fly ash produced, about 40% was beneficially utilized ... . The 2004 survey also shows that out of the fly ash that was beneficially used about 60% was used in cement and concrete applications. Even though ready mixed concrete forms the single largest market for fly ash it can still offer the largest potential for increased fly ash utilization."

In fact, as noted recently by one of West Virginia's own US Congressmen, Representative David McKinley, as reported by the West Virginia Coal Association in:

McKinley: Shame on you, Lisa Jackson - W.Va. rep reacts to outrageous attack on coal | Latest;

and, as we reported in a dispatch yet to be published by the Coal Association, entitled:

"US EPA Headquarters Housed in Coal Ash";

the US Government's own Ronald Reagan office building in Washington, DC, in which the Environmental Protection Agency is housed, is itself constructed, in large part, out of concrete made using Fly Ash from Coal-fired power plants.

Unfortunately, one of the US EPA's own sets of regulations and recommendations concerning the treatment of exhaust gases from Coal-fired power plants, especially as regards the to control of Nitrogen Oxides, makes the resulting Fly Ash, and the cement or concrete which could be made out of that Fly Ash, unsuitable for many applications.

As seen in one of the EPA's own publications concerning the matter:

http://www.epa.gov/ttn/catc/dir1/fnoxdoc.pdf; "EPA-456/F-99-006R; Nitrogen Oxides (NOx), Why and How They Are Controlled; November 1999";

one of their favored and recommended technologies, for dealing with Nitrogen Oxides generated by stationary sources, is the employment of exhaust gas scrubbers utilizing Ammonia, which they specify as:

"Method 3. Chemical Reduction of NOx – This technique provides a chemically reducing ... substance to remove oxygen from nitrogen oxides. Examples include Selective Catalytic Reduction (SCR) which uses ammonia, Selective Non-Catalytic Reduction (SNCR) which use ammonia or urea".

Interestingly, you will find in that report documentation of the fact, that, relative to the emission of Nitrogen Oxides from motor vehicles, and, as well, a number of other human sources which the EPA, seriously,  lumps together under the anonymous title of "Everything Else", the amount of Nitrogen Oxides emitted by all, not just Coal, fossil fuel-burning power plants amounts to just twenty percent of the total NOx created and emitted by human activity.

The gist of how Ammonia is utilized for the control of Nitrogen Oxides in exhaust gas can be gleaned from the full Disclosure of one United States Patent centered on such technology, as in:

"United States Patent: 4911900 - Removing Nitrogen Oxides from a Flue Gas Stream

Date: March, 1990

Inventors: Klaus Horch, et. al., Germany

Assignee: Deutsch Babcock AG, Germany

Abstract: In the selective reduction of nitrogen oxides of flue gases with ammonia, the ammonia is added as ammonia water upstream of the reduction zone. Residual gas phase ammonia and ammonia compounds collected with the flyash serve as recycled ammonia sources and ammonia is formed from them and, in an ammoniacal solution, is added to the ammonia water supply vessel."

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Note, that, as intimated by our brief excerpts, as in "ammonia compounds collected with the fly ash", some of the Ammonia utilized in exhaust gas scrubbers does get entrained in the Fly Ash; and, though some attempt can be made, as indicated, at the recovery of the Ammonia from the Ash, some does get through.

Now, if, as in some of the brief references we've already made, with more to follow, the Fly Ash is to be used as one of the raw materials for the making of basic Portland Cement, that's not too much of a problem, since the heat in the cement kiln should destroy the residual Ammonia.

However, another vast potential for the use of Fly Ash in cement and concrete applications is as one of the inert composite fillers, in addition to, and replacing some of, the ordinary sand and gravel typically used; and, as indicated in our above reference to:

"New Technology Based Approach to Advance Higher Volume Fly ash Concrete with Acceptable Performance", wherein some Ash is utilized, as an aggregate, in "ready mixed concrete".

In that fashion, even more Coal Ash could be consumed and utilized, but in an essentially non-chemical way that leaves anything in the Ash pretty much physically unchanged.

Unfortunately, the entrained Ammonia from the NOx exhaust scrubber is one of those things that remain chemically unchanged; and, it is then free to leach out of the resulting concrete and to make anything made out of that concrete begin to smell like the men's porta-john at the Lions Club's annual 4th of July softball tournament.

As it happens, one public utility in the United States, recognizing the inherent value in Coal Ash, but apparently unwilling to engage in the likely-futile exercise of seeking relief from the EPA regulations concerning NOx reduction, and how to go about achieving that reduction, has devised a system, a set of technologies, for removing residual Ammonia from Coal Ash that has been so contaminated, so that Ash can then be utilized as a concrete, or other, aggregate in civilized applications.

An additional link, and comment, follow excerpts from the initial link in this dispatch to:

"United States Patent 6,755,901 - Ammonia Removal from Fly Ash

Date: June, 2004

Inventors: Bruce Ramme, WI, and Brian Fisher, TX

Assignee: Wisconsin Electric Power Company, Milwaukee

Abstract: A method and apparatus for the application of beat to remove ammonia compounds from fly ash, thereby making the fly ash a marketable product is disclosed. The method includes the steps of providing an amount of fly ash wherein at least a portion of the amount of fly ash comprises particulates having ammonia compounds affixed to the particulates, and exposing the fly ash to flowing air having a temperature of at least 1,500F... such that the fly ash is maintained in the flowing air until the fly ash reaches a temperature of at last 900F... . The apparatus includes a source of fly ash comprising particulates having ammonia compounds affixed to at least some of the fly ash particulates, a heating chamber including a treatment bed comprising a floor having openings, a fly ash supply conduit in communication with the heating chamber and the source of fly ash for transferring fly ash from the source of fly ash to the treatment bed of the heating chamber, a source of heated air, an air supply conduit in communication with the source of heated of heated air and the heating chamber for providing a flow of heated air to the treatment bed of the beating chamber for contacting the fly ash on the treatment bed with the flow of air, a heated air conduit in communication with the beating chamber for transferring the flow of heated air form the heating chamber, and an ash removal conduit in communication with the heating chamber for transferring heated fly ash from the heating chamber.

(Now, that is some pretty-danged hot air. However, in case you haven't noticed, many of our Coal-fired power plants have been compelled to install really big and really expensive water-based cooling towers adjacent to their Coal-fired boilers. You don't suppose, do you, that, instead of just heating water for tea that no one will be drinking, we could, instead, utilize some of that waste heat to help warm the air we'll blowing over our fly ash?

And, since were already at the power plant, won't at least the freshly-produced Ash already be nearly up to the needed temperature?

They do indicate such potentials for related efficiencies in the fuller Disclosure.)

Claims: A method for reducing the amount of ammonia compounds affixed to fly ash, the method comprising: introducing an amount of fly ash into a heating chamber, at least a portion of the amount of fly ash comprising particulates having ammonia compounds (on) the particulates; exposing the amount of fly ash to flowing air having a temperature of at least 1500 F; transferring heat from gases exiting the heating chamber to preheat a second amount of fly ash, at least a portion of the second amount of fly ash comprising particulates having ammonia compounds affixed to the particulates; introducing the second amount of fly ash into the heating chamber; and exposing the second amount of fly ash to flowing air having a temperature of at least 1,500 F. 

The method ... wherein: the amount of fly ash is maintained in the flowing air until the amount of fly ash reaches a temperature of at least 900 F. 

The method ... further comprising: preheating the amount of fly ash to a temperature of at least 300 F before exposing the amount of fly ash to the flowing air. 

The method ... wherein: the second amount of fly ash is preheated to a temperature of at least 300 F. 

The method ... further comprising: removing particulate material from the flowing air after heat has been recovered from the flowing air. 

The method ... further comprising: recovering heat from the particulate material after the particulate material has been removed from the flowing air (and) using the heat recovered from the particulate material to preheat the second amount of fly ash.

The method ... wherein the step of exposing the amount of fly ash to flowing air comprises: providing a metal media having openings; passing flowing air through the openings; and depositing the amount of fly ash on the metal media.

The method ... further comprising: measuring an in process ash temperature of the amount of fly ash when the amount of fly ash is exposed to the flowing air; and controlling a flow rate of the flowing air in response to the measured in process ash temperature.

Background: This Invention relates to the treatment of coal ash to remove ammonia compounds that contaminate the ash as part of post-combustion treatments of exhaust gases to remove nitrogen compounds. 

In 1990, the United States Environmental Protection Agency put into place the Clean Air Act Amendments which were designed to reduce the emissions of 'greenhouse gases'. Among the emissions covered are the nitrogen compounds NO and NO2 referred to generically as NOx. NOx is generated through the combustion of coal and its generation is directly affected by combustion temperature, residency time and available oxygen. Several technologies have been developed to meet the mandated NOx reduction limits. 

The NOx reduction technologies fall into two major categories. One category includes technologies that modify or control the combustion or firing characteristics. The effect of these approaches has been an increase in residual unburned carbon in the coal ash.

(Which "unburned carbon", as we have superficially documented, but as we will document more fully in reports to follow, can, as well, be utilized in various Fly Ash recycling technologies.)

The other category includes technologies that are employed after combustion has taken place. These technologies include selective non-catalytic reduction, selective catalytic reduction, and amine enhanced fuel lean gas reburn. These technologies involve adding ammonia (NH3), and a significant amount of the ammonia finds its way onto the coal ash, typically by combining with available sulphur and other compounds that attach to the ash particles. 

Coal ash is a marketable product if it is not contaminated. The ash may be used, for example, in concrete products as a replacement for a portion of the cement. However, ash that has been treated to reduce NOx and which is contaminated either by unburned carbon or ammonia compounds is not marketable.

There, again, the EPA regs impeding Ash utilization; and, thus, the need for this technology.)

Summary: Accordingly, the present invention is directed to a method and apparatus for the application of heat to remove ammonia compounds from fly ash, thereby making the fly ash a marketable product."

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And, we'll leave our excerpts from "United States Patent 6,755,901 - Ammonia Removal from Fly Ash" there, to emphasize, again, that it is a process to remedy contamination of a Coal-use byproduct, contamination which impairs the otherwise broad commercial utility of that byproduct; and, which contamination, as the "Wisconsin Electric Power Company" clearly states is directly caused by EPA regulations.

In any case, the inventors of our above remedy to certain EPA regs continued their good work in the beneficiation of Ammonia-contaminated Coal Ash, and were, subsequently, awarded another US Patent acknowledging their achievements, as seen in:

"United States Patent: 6945179 - Ammonia Removal from Fly Ash

Date: September, 2005

Inventors: Bruce Ramme, WI, and Brian Fisher, TX

Assignee: Wisconsin Electric Power Company, Milwaukee

Abstract: An apparatus for the application of heat to remove ammonia compounds from fly ash is disclosed. The apparatus includes a source of fly ash comprising particulates having ammonia compounds affixed to the fly ash particulates, a heating chamber including a treatment bed comprising a media having openings, a fly ash supply conduit for transferring fly ash from the source of fly ash to the treatment bed of the heating chamber, a source of heated air, an air supply conduit for providing a flow of heated air to the treatment bed of the heating chamber for contacting the fly ash on the treatment bed with the flow of heated air, a heated air conduit in communication with the heating chamber for transferring the flow of heated air from the heating chamber, and an ash removal conduit in communication with the heating chamber for transferring heated fly ash from the heating chamber.

Claims: An apparatus for reducing an amount of a substance affixed to fly ash, the apparatus comprising: a source of fly ash, at least a portion of the fly ash comprising particulates having a substance affixed to the particulates; a heating chamber including a treatment bed comprising a media having openings; a fly ash supply conduit in communication with the heating chamber and the source of fly ash, the fly ash supply conduit transferring fly ash from the source of fly ash to the treatment bed of the heating chamber; a source of heated air; an air supply conduit in communication with the source of heated air and the heating chamber, the air supply conduit providing a flow of heated air to the treatment bed of the heating chamber for contacting the fly ash on the treatment bed with the flow of heated air; a heated air conduit in communication with the heating chamber for transferring the flow of heated air from the heating chamber; a heat recovery unit for recovering heat from the flow of heated air passing through the heated air conduit; and an ash removal conduit in communication with the heating chamber for transferring heated fly ash from the heating chamber. 

The apparatus ... further comprising: a heater for heating the fly ash passing through the fly ash supply conduit. 

The apparatus ... further comprising: a heat recovery unit for recovering heat from heated fly ash passing through the ash removal conduit. 

The apparatus ... further comprising: a heater for heating the fly ash passing through the fly ash supply conduit, the heater receiving heat recovered by the heat recovery unit from heated fly ash. 

The apparatus ... further comprising: a heater for heating the fly ash passing through the fly ash supply conduit, the heater receiving heat recovered by the heat recovery unit from the flow of heated air. 

The apparatus ... wherein: the substance (affixed to fly ash to be reduced) is selected from the group consisting of ammonia compounds.

Background and Summary: This invention relates to the treatment of coal ash to remove ammonia compounds that contaminate the ash as part of post-combustion treatments of exhaust gases to remove nitrogen compounds.

Accordingly, the present invention is directed to a method and apparatus for the application of heat to remove ammonia compounds from fly ash, thereby making the fly ash a marketable product."

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And, there you have the essence of the thing.

The "apparatus" of "US Patent 6,945,179" is, as we see it, simply the gear we need to carry out the "method" of "US Patent 6,755,901".

In any case, neither would be needed, and Coal "fly ash" would otherwise be a perfectly "marketable product", if not for the fact that it has been polluted with Ammonia by EPA regulations.

And, as herein, we have to expend valuable energy, as in, for one instance, "exposing the amount of fly ash to flowing air having a temperature of at least 1500 F", to remedy such Environmental Protection Agency pollution, so that we can then make "the fly ash a marketable product".

But, - - and we shouldn't be deceived to the contrary by recent press concerning the EPA and their supposedly-official points of view about Coal ash disposal - - in the end, that is the real point:

Even if we have to clean it up a bit, Coal "fly ash" is "a marketable product".


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