Industrial Charcoal Breakthrough
I have copied this material from Renewable Resources Research Laboratory. It is very important, even though they are still in the post prototyping stage and certainly have a lot more fussing around to do.
We have explored traditional methods and so called conventional methods for producing char coal and biochar and have learned both their strengths and shortcomings. The challenge faced was to come up with a basic design that cou8ld be operated at the farm gate and also be scaled to handle any feedstock volume. We seem to have at least the first clear cut demonstration of this principal.
The Q&A part brings home that our economy needs to focus on maximizing charcoal production. The market is clearly unlimited when we accept non woody plant waste char as a soil re mediator.
This also means that forest management can now focus on harvesting waste wood as a matter of course. After all, we are sending a ten ton truck out into the forest every day with a chipper and taking the annual surplus out of the forest. Forest management demands this for best practice. The daily yield is then brought directly to the local flash carbonizer and either kept in inventory to dry or processed.
The carbonizer uses pressure to force a fast burn. This was a bit unexpected, but the ramifications are obvious. It takes perhaps thirty minutes for the heat to fully penetrate the feedstock. The process is not taken to the point of full reduction which leaves a substantial residue of gases and tars. I assume the light gases provide most of the heat. These gases and residues will become continuously available and can be immediately used to fire a boiler for power generation. Any more than that is likely to be swapping dollars.
The point of this is that we have a reliable productivity for the whole spectrum of feed stocks. The principal feedstock can be waste wood fiber. Seasonal sources of agricultural waste can then be folded into fuel stream. Even manure is a good potential feedstock although moisture content might be a problem.
What is very important is that a farmer can bring his load in, have it treated and then take the product back to the farm for soil remediation. I think that we will learn that carbonized cattle manure is a very excellent soil additive.
That sewage waste also makes an excellent product is no surprise and has the added benefit of eliminating the cultural objection to human waste been added to soils.
My earlier arguments for the development of a distributed two lung incinerator system all apply here.
Here we are using pressure but not trying to go to the high pressure methodology that has romanced so many.
I suspect that this is the enabling technology that will now allow industrial scale production of soil charcoal and also a major supply of charcoal suitable for metallurgy and perhaps occasional replacement of coal.
Can you imagine the boreal forests been properly managed for a sustainable crop of waste wood and also a sustainable crop of cattails? This technology makes those types of ideas actually work.
Renewable Resources Research Laboratory
The Renewable Resources Research Laboratory (R3Lab) is a test-bed for the development of innovative technologies and processes for the conversion of biomass into fuels, high-value chemicals, and other products. A consistent theme of the lab's research throughout its history has been the search for new uses for Hawaii's abundant agricultural crops and by-products.
Currently the R3Lab is perfecting the operation of the catalytic afterburner that cleans the effluent of the Flash Carbonization™ Demonstration Reactor. Also, we are producing Flash Carbonization™ charcoal for use in carbon fuel cell research, terra preta and carbon sequestration studies, and metallurgical process research. Finally, we are fabricating an aqueous carbonate/alkaline biocarbon fuel cell that we hope to begin testing soon.
Earlier in its life the R3Lab engaged in research on conversion of biomass into gaseous fuels (hydrogen), and liquid fuels (ethanol). Reprints of publications are available upon request to Prof. M.J. Antal.
News Item: Recently we began Flash Carbonization™ studies of raw sewage sludge produced in Honolulu's Ewa sewage sludge treatment plant. We were surprised by the ease with which air-dry sewage sludge can be converted into charcoal. We obtained charcoal yields of about 30% (dry basis) from the sewage sludge. The charcoal contained 45-51% ash and 40% fixed-carbon. Studies of the use of sewage sludge charcoal as a soil amendment (i.e., terra preta application) with the side-benefit of carbon sequestration are now beginning at UH. Results of these studies will be reported at the forthcoming AIChE meeting in Philadelphia (November, 2008).
A recent article appeared in the Honolulu Advertiser newspaper about the Flash Carbonization™ process. The following is a question and answer explanation relative to that article.
Q1: You mention that the University has licensed the Flash Carbonization™ technology to several companies that plan to use it for the commercial production of charcoal. Can you tell us who these companies are?
A1: Our three current licensees are Carbon Diversion Corp., which has operations here in Hawaii; the Kingsford Products Company, which most people recognize as the largest manufacturer of BBQ charcoal in the world; and Pacific Carbon and Graphite. Licenses are also being discussed with other companies on the US mainland, in Canada, and elsewhere in the world.
Q2: Isn't charcoal merely a barbeque fuel?
A2: No! Charcoal is the sustainable fuel replacement for coal. Coal combustion is the most important contributor to climate change. Coal combustion adds about 220 lb of CO2 to the atmosphere for every million BTU of energy that it delivers; whereas crude oil adds 170 lb per million BTU, gasoline adds 161 lb per million BTU, and natural gas adds 130 lb of CO2 to the atmosphere per million BTU of delivered energy. On the other hand, the combustion of charcoal - sustainably produced from renewable biomass - adds no CO2 to the atmosphere! Thus, the replacement of coal by charcoal is among the most important steps we can take to ameliorate climate change.
Q3: Do we burn coal to generate electrical power here in Hawaii?
A3: Yes! In the year 2000 we operated a 180 MW coal fired power plant on Oahu, a 22 MW power plant on the Big Island, and a 12 MW coal and bagasse fired power plant on Maui. The HC&S Puunene power plant on Maui could be the perfect starting point for replacement of coal by charcoal. The highest priority for knowledgeable people who care about the environment is the replacement of coal by cleaner, renewable fuels.
Q4: Why doesn't the combustion of charcoal add to the CO2 burden of the atmosphere and thereby cause climate change?
A4: The combustion of charcoal does not add to the CO2 burden of the atmosphere because charcoal is produced from waste wood, crop residues, and other renewable biomass that would otherwise decompose (i.e. rot) in a landfill or in the ground and become CO2. Thus the combustion of charcoal is a small part of nature's great carbon cycle upon which life depends.
Q5: Does the replacement of coal by charcoal have other benefits?
A5: Yes! Coal is laden with mercury and sulfur. Mercury is a deadly toxin. Mercury from the combustion of coal in China has been found in fish taken from the Great Lakes in the USA. Thus mercury emissions can be windborne and carried across continents and oceans. New regulations concerning the release of mercury to the atmosphere may greatly increase the cost of electric power generation by coal combustion. Similarly, because coal is also laden with sulfur, the combustion of coal leads to the release of sulfur oxides into the atmosphere. Sulfur oxides are a principal cause of acid rain. In contrast, charcoal contains no mercury and virtually no sulfur. In fact, our drug stores sell charcoal tablets to eat as an aid for digestion! Moreover, on a pound per pound basis, charcoal contains much more energy than most coals.
Q6: Are you suggesting that charcoal would be a better choice than ethanol for the sustainable production of electric power here in Hawaii?
A6: Yes! From the standpoints of resource utilization, energy efficiency, and economics; charcoal is preferred over ethanol as a fuel for electric power generation.
Here in Hawaii we have an abundance of macadamia nut shells and husks, green wastes including tree trimmings, wood logs, coconut shells and husks, and increasing amounts of invasive species (e.g. gorse wood, strawberry guava) that should be contained or eradicated. These biomass feedstocks cannot be converted into ethanol in a practical process, but they are all ideal feedstocks for the production of charcoal.
Likewise, as a result of seed corn production, we also have significant amounts of corn stover including cobs. If this stover is converted into charcoal, the charcoal retains 59% of the energy content of the stover. This energy conversion efficiency (i.e. 660 lb charcoal per ton of dry stover) has been proven in the commercial scale Flash Carbonization™ reactor that is in operation on the UH campus. On the other hand, if the corn stover is converted into ethanol, the conversion efficiency is projected to be only 43% (i.e. 85 gal of ethanol per ton of stover). We emphasize that this efficiency is an optimistic projection, since the conversion of corn stover into ethanol is unproven on a commercial scale. Thus a ton of corn stover will deliver 37% more energy if it is converted into charcoal instead of ethanol. That's 37% more energy available for the generation of electric power!
Furthermore, because of tax incentives ethanol does not appear to be an expensive fuel. But appearances can be deceptive, especially in light of the relatively low energy content of a gallon of ethanol. The current rack price nationwide of a gallon of ethanol is $2.40. Reflecting the low energy content of ethanol this price is $3.66 per gallon of gasoline equivalent (i.e. $31.75 per million BTU). Note that this price includes no taxes. The comparable price of imported charcoal is $279/ton, or $0.79 per gallon of gasoline equivalent (i.e. $10.48 per million BTU). Thus the price of ethanol is 3 times more expensive than charcoal! Also, note that the production of charcoal enjoys no Federal tax credits; nevertheless, on an energy basis charcoal is about 87% the price of crude oil at $70 per bbl ($12 per million BTU). Given the high price of ethanol, Hawaiian consumers of electric power should contemplate the very large increase in their energy cost adjustment that will appear if ethanol begins to be used as a boiler fuel to generate electricity!
Q7: What about HECO's plan to use biodiesel produced from imported palm oil to fuel a 110 MW power plant in the Campbell Industrial Park?
A7: Biodiesel fuel (B100) is manufactured from vegetable oils. Anyone who purchases vegetable oils for salads or cooking knows that these oils are expensive. Thus, common sense leads us to expect that B100 - manufactured from soy, canola, rapeseed, or palm oil - will be expensive. The Union of Concerned Scientists predicts that the price of B100 will be double that of diesel fuel. The National Renewable Energy Laboratory estimates the price of B100 from soy oil will exceed $2.40 per gallon, and from canola oil will exceed $3.00 per gallon. In Seattle the recent price of B100 was $3.29 per gallon.
If we make the optimistic assumption that B100 will cost $3.00 per gallon, HECO will be paying about $25 per million BTU (or $2.89 per gallon of gasoline equivalent without taxes) for its boiler fuel. On an energy basis, this is 2.4 times the comparable price of charcoal. As with ethanol, Hawaiian electric power consumers will be shocked by the energy cost adjustment that will be added to their bill when B100 is burned to generate electric power.
Q8: Is charcoal being used for the commercial production of electric power anywhere?
A8: Yes! The largest charcoal producer in Europe, the Carbo Group BV, has sold substantial quantities of wood charcoal to ESSENT for co-firing in their Borselle coal fired station.
Q9: If charcoal is so inexpensive, can a business make a profit producing charcoal?
A9: Yes! The cost of producing a ton of charcoal in the USA is usually much less than $200, depending upon the local cost of biomass and labor. The wholesale price of charcoal imports during 2006 was $279 per ton. Obviously, the production of charcoal is a very profitable enterprise.
Q10: Does charcoal have any uses besides fuel for barbeque and electric power generation?
A10: Yes! Iron, steel, and ferrosilicon alloys are all produced using a carbon reductant. Almost one pound of carbon is consumed to produce a pound of steel. In the USA coal ("coke") is used as the carbon reductant and this use of coal adds substantial amounts of CO2 to the atmosphere and is an important contributor to climate change. Brazil and Norway use charcoal instead of coal to produce iron, steel, and ferrosilicon alloys. As the steel industry moves to reduce its carbon footprint, the demand for charcoal as a substitute for reductant coal will explode.
Also, here in Hawaii charcoal is an important ingredient in potting soils, and is the preferred rooting medium for orchids. Moreover, the addition of charcoal to soil has been shown to greatly enhance the growth of corn and other cash crops. This use of charcoal to enrich the soil is attracting much attention around the world as a practical means for permanently sequestering carbon from the atmosphere.
A11: No. A local company, Carbon Diversion Corp., has exclusive rights to manufacture charcoal using the UH Flash Carbonization™ process here in Hawaii and in parts of the Pacific basin. Carbon Diversion is headed by Michael Lurvey; a prize winning MBA graduate of the UH Business School, and a Vietnam veteran.
Q12: What does this all mean for Carbon Diversion?
A12: The markets for charcoal as a boiler fuel for the sustainable production of electricity, a reductant for the sustainable production of metals, and a soil amendment for sustainable agriculture and carbon sequestration are enormous. We believe that Carbon Diversion is destined to become one of the Exxons of the 21st century.
Flash Carbonization™ process
Research at the University of Hawaii (UH) has led to the discovery of a new Flash Carbonization™ process that quickly and efficiently produces biocarbon (i.e., charcoal) from biomass. This process involves the ignition of a flash fire at elevated pressure in a packed bed of biomass. Because of the elevated pressure, the fire quickly spreads through the bed, triggering the transformation of biomass to biocarbon. Fixed-carbon yields of up to 100% of the theoretical limit can be achieved in as little as 20 or 30 minutes. (By contrast, conventional charcoal-making technologies typically produce charcoal with carbon yields of much less than 80% of the theoretical limit and take from 8 hours to several days.) Feedstocks have included woods (e.g., leucaena, eucalyptus, and oak), agricultural byproducts (e.g., macadamia nutshells, corncobs, and pineapple chop), wet green wastes (e.g., wood sawdust and Christmas tree chips), various invasive species (e.g., strawberry guava), and synthetic materials (e.g., shredded automobile tires). Results of many of these tests are described in a series of technical, peer-reviewed, archival journals paper that can be obtained by request to Prof. M.J. Antal.
We are now testing a commercial-scale, stand-alone (off-the-grid) Flash Carbonization™ Demonstration Reactor ("Demo Reactor") on campus (see photos below). The first successful test occurred on 24 November 2006. A canister full of corn cobs was carbonized in less than 30 min. This test proved that the Flash Carbonization™ process can be scaled-up to commercial size.
Recently HNEI received a two-year $215,000 research grant from the Consortium on Plant Biotechnology Research (CPBR) for "Flash Carbonization™ Catalytic Afterburner Development." The CPBR funding will enable us to make progress towards the elimination of smoke and tar from the reactor's effluent.
After we satisfy all emissions regulations, the University will team with its licensee for the State of Hawaii (Carbon Diversion Corporation) and use the equipment to convert green wastes into charcoal. Large, dense, green waste feedstocks (e.g., tree logs, coconut shells) will be marketed as barbeque charcoal. Lighter material (e.g., tree trimmings and macshells) will be marketed as orchid potting soil (see below). Some charcoal may also be marketed as an ultra-clean coal. Synthetic materials (e.g., shredded automobile tires and other shredded synthetics) may also be carbonized. When it is fully operational, the Demo Reactor will have the capacity to produce about 10 tons of charcoal per 24 hr day and provide employment to two or three workers. The capital cost of the Flash Carbonization™ Demonstration Reactor (pictured above), gantry, and two canisters was about $200,000 (including delivery to
The Flash Carbonization™ technology is protected by U.S. Patent No. 6,790,317. The UH has applied for patents on the Flash Carbonization™ process in many other countries, and these patents are pending. The first license for charcoal production was signed in 2003. Since then Carbon Diversion Corp. has acquired an exclusive license for the State of Hawaii and various islands in the Pacific region, and the Kingsford Products Co. has acquired a license. Inquiries from other firms, in the US and around the world, are welcome. The University's licensing approach has been to grant territorial exclusivity with regard to production of Flash Carbonization™ charcoal and non-exclusive rights to sell such charcoal worldwide. All licensing activity is handled by the Office of Technology Transfer and Economic Development (OTTED).
Based on this prior experience, we recommend that a potential licensee take the following steps to determine if the Flash Carbonization™ process represents an attractive technology for adding value to locally available biomass feedstocks.
Contact Professor Michael J. Antal, Jr. and provide information on the proposed region for practice of the technology, the feedstock characteristics, etc. The potential licensee should have the ambition and the ability to produce and market at least 10,000 tons per year of charcoal.
Visit Professor Antal and Richard Cox (OTTED) to discuss license terms. The potential licensee should have significant engineering expertise.
Test the proposed feedstock's carbonization behavior in the Lab Reactor. This test costs $1000 and typically requires about 1 month to complete (including the shipping time of the biomass sample to Hawaii).
If you plan to use the FC process to produce charcoal in a region where the UH holds patents (ie., the
HNEI will assist licensees of its Flash Carbonization™ technology by offering apprenticeship training that includes a parts list, drawings, an operator's manual, and intensive training in the operation of Flash Carbonization™ reactors that are now being operated and tested on campus. The apprenticeship program can accommodate more than one apprentice from a single licensee; it is scheduled at the mutual convenience of the licensee and HNEI, and it has a typical duration of 3 weeks. Note that the apprenticeship program is only offered to licensees of the technology.
Biocarbon Fuel Cells
HNEI researchers have fabricated and tested a moderate-temperature, aqueous-alkaline "direct" carbon fuel cell that "burns" charcoal as its fuel and directly generates electricity. The exciting results of this research are described in a technical paper that has just been published. The abstract of the paper appears below. Reprints of this paper are available upon request to Prof. M. J. Antal. Currently Prof. Antal and his team are fabricating an aqueous carbonate/alkaline biocarbon fuel cell that has been designed to achieve higher voltages and power densities. We hope to begin testing this new carbon fuel cell later this year.
Because the carbon fuel cell has the potential to convert the chemical energy of carbon into electric power with an efficiency approaching 100%, there has been a keen interest in its development for over a century. A practical carbon fuel cell requires a carbon feed that conducts electricity and is highly reactive. Biocarbon (carbonized charcoal) satisfies both these criteria, and its combustion does not contribute to climate change. In this paper we describe the performance of an aqueous-alkaline biocarbon fuel cell that generates power at temperatures near 500 K. Thermochemical equilibrium favors the reduction of oxygen on the cathode at temperatures below 500 K; whereas the chemical kinetics of the oxidation of carbon by hydroxyl anions in the electrolyte demands temperatures above 500 K. Nevertheless, an aqueous-alkaline cell operating at 518 K and 35.8 bar was able to realize an open-circuit voltage of 0.57 V, a short-circuit current density of 43.6 mA/cm², and a maximum power of 19 mW by use of a 6 M KOH/1M LiOH mixed electrolyte with a catalytic Ag screen/Pt foil cathode and an anode composed of 0.5 g of compacted corncob charcoal previously carbonized at 950 °C. A comparison of Temperature Programmed Desorption (TPD) data for the oxidized biocarbon anode material with prior work suggests that the temperature of the anode was too low: carbon oxides accumulated on the biocarbon without the steady release of CO2 and active sites needed to sustain combustion; consequently the open-circuit voltage of the cell was less than the expected value (1 V). Carbonate ions, formed in the electrolyte as a product of the reaction of CO2 with hydroxyl ions, can halt the operation of the cell. We show that the carbonate ion is not stable in hydrothermal solutions at 523 K and above; it decomposes by the release of CO2 and the formation of hydroxyl anion. Consequently it should be possible to regenerate the electrolyte by use of reaction conditions similar to those employed in the fuel cell. We believe that substantial improvements in performance can be realized from an aqueous-alkaline cell whose cathode is designed to operate at temperatures significantly below 500 K, and whose biocarbon anode operates at temperatures significantly above 500 K.
High-Yield Activated Carbons from Biomass
Activated carbons made from biomass (i.e., coconut shells) charcoal are used to purify water and air. The R3Lab has developed an air oxidation process that produces high-yield activated carbons from biomass charcoal. This work was supported by the National Science Foundation.
A conventional method for hydrogen production from fossil fuels involves the reaction of water with methane (steam reforming of methane) at high temperatures in a catalytic reactor. Research sponsored by the U.S. Department of Energy led to the development of a process by the R3Lab for hydrogen production by the catalytic gasification of biomass in supercritical water (water at high temperature and pressure). This "steam reforming" process produces a gas at high pressure (>22 MPa) that is unusually rich in hydrogen. Researchers at the Institut fur Technische Chemie CPV, Forschungszentrum Karlsruhe in Karlsruhe, Germany are commercializing a biomass gasification process that employs the conditions identified by the R3Lab in its pioneering work. However, research on this topic within HNEI halted after a U.S. Department of Energy economic study projected dismal economics for the process
The R3Lab has been a leader in the development of a pretreatment process that employs hot liquid water to render lignocellulosic biomass susceptible to simultaneous saccharification and fermentation for the production of ethanol. This process can also be used to produce microcrystalline cellulose from biomass. The research was supported by the U.S. Department of Agriculture and the Consortium for Plant Biotechnology Research.
Contact: Michael J. Antal, Jr.
Renewable Resources Research Laboratory