http://www.netl.doe.gov/
Right off the bat, we want to call attention to the way the United States Department of Energy titles the information we bring to you in this dispatch.
We note first, without referencing any of our past reports documenting the fact, since many more are to follow, that we have already many times documented that Coal Fly Ash, and even Flue Gas Desulfurization scrubber sludge, have rather large potentials for use in the making of cement and concrete, and other basic construction materials.
There are other quite significant uses for those byproducts, as well, some of which we have documented, and some which we will also get to in the due course of time.
Their potentials for productive use are so significant that a number of trade organizations have arisen to promote those uses, including, as accessible via:
ACAA - Promoting & Advancing Coal Combustion Products;
The American Coal Ash Association, who tell us that their "mission is to advance the management and use of coal combustion products in ways that are environmentally responsible, technically sound, commercially competitive, and supportive of a sustainable global community".
And, Coal Country Universities also participate, including through their Center for Applied Energy Research, the University of Kentucky; who tell us, as seen in:
that: "CCBs are minerals that remain after coal is burned to generate electricity".
The above, we submit, is a very limited definition of Coal-use residuals; perhaps one dictated by political correctness; since, we further note, that, the mineral residues resulting from the conversion of Coal into more versatile hydrocarbon liquids and gases are, in terms of chemical composition, closely-similar to the residues that result from the simple burning of Coal to generate electrical power.
That fact was acknowledge by both ExxonMobil and our own US Government, via the United States Patent and Trademark Office, as seen in our report of:
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; 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."
And, may blessings be upon them for their, though sadly indirect, intellectual rectitude, that fact is also acknowledged, obliquely, by our own United States Department of Energy.
Herein, via the initial and a following link in this dispatch, we submit documentation of the USDOE's very own exposition of how we can utilize, not "Coal Combustion Products", CCP's, or Coal Combustion Byproducts, CCB's, but: "Coal Utilization Byproducts", "CUB"s.
Comment is inserted within and follows excerpts from:
"Clean Coal Technology: Coal Utilization Byproducts
Executive Summary: The Clean Coal Technology Demonstration Program (CCTDP) is a government and
industry cofunded effort to demonstrate a new generation of innovative coal utilization processes in a series of facilities built across the country. These projects are carried out on a commercial scale to prove technical feasibility and provide information for future applications.
The goal of the CCTDP is to furnish the marketplace with advanced, more efficient coal-based technologies that meet strict environmental standards. Use of these technologies is intended to minimize the economic and environmental barriers that limit the full utilization of coal.
(And, just to be clear what we take some of the good folk at the USDOE to mean when they speak of the "full utilization of coal", in addition to the generation of electricity, see, for just one example, our report of:
USDOE Hydrocracks Coal with Steam and Carbon Monoxide | Research & Development; concerning: "United States Patent 4,225,414 - Hydrocracking Carbonaceous Material to Provide Fuels; 1980; Assignee: The United States of America; Abstract: A process is disclosed for hydrocracking coal or other carbonaceous material to produce various aromatic hydrocarbons including benzene, toluene, xylene, ethylbenzene, phenol and cresols in variable relative concentrations ... (which) can be used to produce desired materials for chemical feed stocks or for fuels.The invention described herein was made in the course of, or under, a contract with the U.S. Department of Energy. (It) is an object of the present invention to provide a method of hydrocracking carbonaceous material ... to produce various aromatic feedstocks for chemical processing or for blending as high octane stock in motor vehicle fuels".)
To achieve this goal, beginning in 1985, a multiphase effort consisting of five separate solicitations was administered by the U.S. Department of Energy (DOE) through its National Energy Technology Laboratory.
Selected projects have demonstrated technology options with the potential to meet the needs of energy markets while satisfying relevant environmental requirements. Two follow-on programs have been developed
that build on the successes of the CCTDP: the Power Plant Improvement Initiative (PPII) and the Clean Coal Power Initiative (CCPI).
Under the latter programs, three projects have been selected or are underway with the goal of increasing the use of coal utilization by-products (CUBs) in construction and other industries.
CUBs are the solid materials formed during the combustion or gasification of coal during electric power generation. The primary large-volume CUBs are fly ash, bottom ash, slag, ash produced via fluidized bed combustion, and flue gas desulfurization by-products. Historically, CUBs have been disposed of in ash ponds, landfills, and other sites. However, there are many incentives for developing more beneficial uses for these materials, including power generation economics, the conservation of natural resources and landfill space, and reductions in carbon dioxide emissions.
(Speaking of "carbon dioxide emissions", CO2, as well, should be seen as a "CUB", even though it's not one of the "the solid materials formed during the combustion or gasification of coal". And, even though the USDOE doesn't afford CO2 "CUB" status, they have most certainly addressed it's "use ... in other industries", as seen, for just one example, in our report of:
USDOE Converts CO2 to Gasoline | Research & Development; concerning a technology developed at the USDOE's Brookhaven, NY, National Laboratory: "United States Patent 4,197,421 - Synthetic Carbonaceous Fuels and Feedstocks; 1980; Assignee: The United States of America; Abstract: This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends.")
As time passes, more and more CUBs are being sold or reused—over 40 percent in 2004 compared to less than 25 percent in 1996 while at the same time production of CUBs has increased significantly. Government agencies and other stakeholders have established a goal of 50 percent utilization by 2010.
Although these materials have been referred to as coal combustion products (CCPs), residues, or wastes, the U.S. Department of Energy (DOE) prefers the term “utilization” over “combustion” because it accounts for coal gasification, which also produces solid by-products that must be managed.
(Such "coal gasification" can be performed to generate a gaseous fuel for use in the generation of electricity, as seen via:
http://www.clean-energy.us/
"Tampa Electric's Successful 250 MW Coal Gasification Power Plant Project; Coal/water slurry and oxygen are reacted at high temperature and pressure to produce a medium-Btu syngas in a Texaco gasifier. Molten ash flows out of the bottom of the gasifier into a water-filled sump where it is forms a solid slag. The syngas moves from the gasifier to a high-temperature heat-recovery unit, which cools the syngas while generating high-pressure steam. The cooled gases flow to a water wash for particulate removal. Next, a COS hydrolysis reactor converts one of the sulfur species in the gas to a form that is more easily removed. The syngas is then further cooled before entering a conventional amine sulfur removal system. The amine system keeps SO2 emissions below 0.15 lb/106 Btu (97% capture). The cleaned gases are then reheated and routed to a combined-cycle system for power generation";
or, especially since it's "a Texaco gasifier" that's being used to convert Coal into, as above, "a medium-Btu syngas", then, as seen in:
Texaco 1958 Coal Hydrogasification | Research & Development; concerning:
"United States Patent 2,838,388 - Gasifying Carbonaceous Fuels; 1958; Assignee: The Texas Company (i.e., Texaco); Abstract: This invention ... relates to an improved method for the synthesis of hydrocarbons from solid carbonaceous fuels. ... The process ... is particularly applicable to the treatment of coal ... .
Carbonaceous fuels other than ... liquid hydrocarbons ... may be converted to motor fuels by the Fischer-Tropsch synthesis. The carbonaceous fuel is first reacted with oxygen and steam to produce a mixture of carbon monoxide and hydrogen as the synthesis feed gas ... which is, in turn, converted ... (to) ... motor fuels";
such Coal-derived "syngas" could instead be catalytically condensed into "liquid hydrocarbons" and "motor fuels".)
Similarly, DOE prefers the term “by-products” because it describes most accurately the nature of the materials at the moment they are generated. They become “products” when they are sold or beneficially
utilized and “wastes” when they are sent to a permanent disposal site.
In 1980, CUBs were designated nonhazardous wastes by the Bevill Amendment to the Resource Conservation and Recovery Act. Further investigation has found that their properties often allow their beneficial use. In some cases, these properties make the CUB better suited for certain applications than the naturally occurring materials they replace.
The most common and economical use for Class C fly ash is as a partial replacement for Portland cement in concrete manufacturing (normally up to 30 percent, but can be as high as 50 percent in some applications). In 2004, approximately 14 million tons were used in this capacity, generating several hundred million dollars in revenue and demonstrating the wide acceptance fly ash enjoys in the concrete industry.
Two significant benefits are realized when fly ash is used to displace Portland cement.
First, aluminosilicates in the ash react with calcium hydroxide, augmenting its cementitious properties and increasing the strength and durability of the final product.
Second, Portland cement production releases high levels of CO2. For every ton of fly ash used in replacement, one ton of CO2 emission is avoided.
(The above important issue is one we have several times previously documented, and centers on the fact that not only is fuel burned to generate the heat needed to calcine limestone into cement, and thus generating Carbon Dioxide through combustion, but, the calcination reaction itself, "CaCO3 + Heat = CaO + CO2", produces one molecule of Carbon Dioxide, CO2, for each molecule of cement, or lime, CaO, produced from limestone, CaCO3. For each part of limestone replaced by Coal fly ash, at least one part of Carbon Dioxide emission is avoided. )
In addition to cement manufacture, fly ash is used to produce controlled low strength material, also known as flowable fill, and as a filler in plastic compounds.
Flowable fill pours freely, sets up quickly, and has the strength of compacted soil. In construction, it cuts man-hours and improves worker safety by allowing trenches to be backfilled remotely rather than manually.
In mining, it is used as backfill and is especially useful in preventing underground mine subsidence.
(The above are issues we will address, though briefly, in future reports. We prefer uses wherein value-added products are actually being made, with the avoidance of utilizing other valuable raw materials.)
The finest-sized fly ash is used as filler in plastic compounds, increasing the stiffness of the plastic and reducing production cost by displacing plastic resin.
(Concerning the use of Fly Ash "as filler in plastic compounds", see, for example, our report of:
Carbon Dioxide + Coal Fly Ash = Synthetic Lumber | Research & Development; concerning, in part: "United States Patent Application 20080029925 - Filled Polymer Composite and Synthetic Building Material; 2008; Abstract: The invention relates to composite compositions having a matrix of polymer networks and dispersed phases of particulate or fibrous materials. The matrix is filled with a particulate phase, which can be selected from one or more of a variety of components, such as fly ash particles".)
Of the 70.8 million tons of fly ash available annually, approximately 16.5 million tons are used as a replacement for Portland cement in concrete manufacturing and as a component of the kiln feed to produce clinker. In 2004, the United States used approximately 121 million tons of Portland cement, of which fly ash with acceptable properties could have replaced at least 30 percent (36.1 million tons).
High-volume construction is another, potentially large market for fly ash and one favored by EPA. The ash can be used in road construction, as structural and mine fill, and for waste stabilization.
(Concerning the EPA, see, for instance, our report of:
US EPA Headquarters Housed in Coal Ash | Research & Development; wherein it's documented, that: "fly ash has been used in concrete since the 1930’s. Most notably, it has been used in several construction projects and prominent buildings, including the Ronald Reagan Government Office building, home to the Environmental Protection Agency (EPA) in Washington, D.C.".)
CUB reuse carries with it many economic and environmental advantages, including cost savings to the power industry, conservation of natural resources and landfill disposal space, and reduced CO2 emissions.
The challenges are to ensure that CUBs produced are available and salable and continue to find profitable market outlets."
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The full document is much more informative than our necessarily-brief excerpts would suggest.
And, the USDOE's program is even more comprehensive, and goes even further, as evidence by yet another of their reports, from their National Energy Technology Laboratories, concerning the same potentials, as accessible via:
http://www.netl.doe.gov/
"Commercial Use of Coal Utilization By-products and Technology Trends
The availability of affordable energy will continue to be essential to our Nation’s economic strength. At present over half of the electrical energy demand in the United States is met by the combustion of coal and the reliability of low cost coal-fired power has been a significant factor in our Nation’s economic growth and development.
(Please note that above acknowledgement of Coal's overriding importance to our economy.)
Demand for electricity is expected to increase steadily throughout the future, and coal will continue to play a significant role in meeting this demand. However, the contribution of coal to the Nation’s energy mix, and the overall cost of electricity, will increasingly depend on our ability to find economical ways to reduce or eliminate any potential adverse environmental impacts associated with the disposal and utilization of coal combustion by-products.
Despite the demonstrated capability of newer, Clean Coal technologies to meet future power and environmental demands, the electric power industry’s response to the 1990 Clean Air Act has been to increase the levels of environmental control at existing plants that produce “conventional” coal utilization by-products (CUB) such as fly ash, bottom ash, and wet FGD sludge. For example, the industry’s response to the Act’s mandate to reduce emissions of nitrogen oxides has been to install low-NOx burners; the fly ash produced from these burners can have unburned carbon contents which render the ash unsuitable for use in cement manufacture. This has eliminated a source of revenue for power producers and increased the total cost of their by-product management operations.
(We've previously documented the above-noted disadvantages imposed by Clean Air Act regulations. As we will further document, technologies have been devised to correct the problems thus caused in the potential use of CUBs; all, though, entailing some additional expense.)
Also, the response of many major utilities to SO2 emissions requirements has been to accelerate the use of wet FGD devices rather than switch to “clean” coal combustion technologies. The result has been an excessive growth in the production of wet FGD material that is outpacing the utilities’ capacity to utilize the material. The American Coal Ash Association (1997) has estimated that less than 7% of the FGD by-product is currently being utilized. Concurrently, the implementations of increasingly stringent solid waste disposal regulations at the state and local level have increased the cost of developing new landfill capacity for all CUB’s. Therefore, the environmentally beneficial utilization of wet FGD by-products, high-LOI ashes, and other utility by-products for which commercial markets have not been well-developed.
(There are, though, as seen in:
Synthetic Gypsum from Coal Power Plant Flue Gas | Research & Development; concerning: "United States Patent 7,776,150 - Process and Apparatus for Handling Synthetic Gypsum; 2010; Koppern Equipment Company, NC, and Giant Cement Company, SC; Method and apparatus for converting wet synthetic gypsum from a flue desulphurization process (FGD) to easily handled and metered briquettes"; and, in:
Pittsburgh Makes Coal Flue Gas Gypsum for Fly Ash Cement | Research & Development; concerning: "US Patent 5,312,609 - Sulfur Dioxide Removal from Gaseous Streams with Gypsum Product Formation; 1994; Assignee: Dravo Lime Company, Pittsburgh; Abstract: A method is provided for removing sulfur dioxide from a hot gaseous stream while directly producing .alpha.-hemihydrate gypsum from a scrubber effluent";
some "commercial markets" for the "FGD by-products", though they could certainly be increased.)
The Coal Combustion Products Partnership (C2P2) program is a cooperative effort between the U.S. Environmental Protection Agency, American Coal Ash Association, Utility Solid Waste Activities Group, US Department of Energy, and US Federal Highway Administration to help promote the beneficial use of coal utilization by-products and the environmental benefits that result from their use.
The physical and chemical characteristics of fly ash make it well-suited for use in cement and concrete.
Most importantly, the chemical composition of many fly ashes is similar to that of Portland cement consisting mainly of silica, alumina, and calcium oxides. Fly ashes usually have much lower amounts of calcium oxides than cement mixtures. Such fly ashes tend to be pozzolanic in nature; pozzolans are substances that do not form cementatious compounds on their own when exposed to water, but will react in the presence of water and calcium hydroxide to create cementatious compounds.
Many different types of fly ashes can be used successfully in concrete, at rates ranging from 5 to 30 percent of the cement portion of the concrete mixture.
In addition to its advantage in poured structural concrete, fly ash is frequently used in the manufacture of concrete masonry units (blocks) to add plasticity to the concrete mixture and to produce blocks with better texture and better corners. Fly ash also increases the service life of the molds used to form the concrete blocks. Depending on the type of curing used, fly ash can be added to replace from 20 percent to as much as 50 percent of the cement in the block manufacturing process.
Fly ash can also be used successfully in the cement/concrete industry is as a raw material in the manufacture of Portland cement. In this application, the pozzolanic properties of the fly ash are not important. Its usefulness stems from the fact that its bulk chemical composition is very similar to shale or clays that are commonly used as feed materials to cement kilns.
Asphalt pavement normally consists of a blend of a bituminous asphalt binder, coarse aggregate, and a fine-grained additive, commonly referred to as mineral filler. Fly ash has been used since the early 1930's as mineral filler in bituminous asphalt mixes. The low plasticity and fine, relatively uniform grain size of fly ash make it particularly suitable for this application. Since the advantage of using fly ash does not relate to its pozzolanic behavior, fly ashes that do not meet ASTM specifications for use in concrete pavements can often be used successfully as mineral fillers in asphalt pavements."
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We'll close there, although both of the main references that are the core of this dispatch go on at far greater length to more fully describe the above, and other, uses for "CUBs", since we are at work now on reports concerning the use of Coal Ash, as immediately above, "as mineral fillers in asphalt pavements".
Like the use of Coal Ash as both a raw material for the manufacture of Portland Cement and as an aggregate in that cement, to form concrete, there are special properties attributed to Coal Ash which, in fact, lead to the formation of better, more durable road pavement surfaces when Coal Ash is used, instead other mineral fillers, as the aggregate in asphalt paving mixtures applied to road beds.
As with the potentials for recycling our favorite gaseous "CUB", Carbon Dioxide, as seen again in:
Illinois Algae Convert Flue Gas CO2 into $60 Oil for USDOE | Research & Development; concerning: "Removal of Carbon Dioxide from Flue Gases by Algae;1993; Institute of Gas Technology, Chicago; Illinois Dept. of Energy and Natural Resources, Springfield, IL (and) USDOE, Washington, DC; The objective of this research program is to determine the feasibility of the alga Botryococcus braunii as a biocatalyst for the photosynthetic conversion of flue gas CO2 to hydrocarbons";
we don't have a problem with "wastes" arising from our essential and vital use of Coal in the generation of economical electricity.
What we do have is an immense economic opportunity for United States Coal Country, in the profitable recycling and reuse of all of our Coal Utilization Byproducts.