Companies Partner to Advance Metal-Bath Gasification Technique for Coal-to-Liquids
22 April 2006
|Depiction of the HydroMax process.|
Diversified Energy Corporation and Alchemix Corporation are working together to accelerate the development of Alchemix’ HydroMax process, a distinct approach to gasification for hydrogen production or the production of a syngas for Fischer-Tropsch conversion into liquid fuels.
Although HydroMax can process a variety of hydrocarbon feedstocks, including biomass waste, sludge, and old tires, the partnership is focusing on the development of coal-to-liquids processing, with Alchemix providing the gasification front-end to the Fischer-Tropsch process.
Following a detailed analysis of the current US energy situation, worldwide energy demand, limited oil and natural gas supplies and an assessment of all potential energy alternatives, we concluded that gasification must be an element of the country’s energy portfolio.
Transportation fuels, which account for nearly all petroleum imports, will experience severe price increases as a result of decreasing oil supply and increasing worldwide demand. One HydroMax plant can produce 242 Million gallons of conventional transportation fuel per year, enough to power 240,000 automobiles, and we are convinced that this technology will have a major energy and economic impact.—W. David Thompson, Diversified CEO
The United States has a 275-year supply of coal and there is more energy value in coal under the state of Illinois alone than in all of Saudi Arabia. HydroMax allows us to put the US on the path to energy independence. Doubling our current coal production would provide us with enough energy to replace all imported oil.—Robert Horton, Alchemix Chairman
Under terms of the agreement, Diversified Energy will invest $5 Million in Alchemix in exchange for stock, a technology license, and a management/development contract for the HydroMax demonstration program. The two companies are currently pursuing both government and public/private equity sources to complete funding of a pilot-plant demonstration program. Major industrial and utility strategic partners are also being sought to support technology and commercial plant development.
Alchemix designed the HydroMax process to be lower in cost than more conventional gasifications technologies. The company asserts that HydroMax could reduce gasification capital costs by a 50%, and undercut the production economics of conventional steam methane reforming (SMR) or the gasification of petroleum coke by a factor of ten. On the other hand, the process throws off more carbon dioxide—65% more when compared to Steam Methane Reforming.
(Alchemix is quick to point out that when biomass, sewage sludge or municipal waste is used as the carbon source, the process is CO2 neutral since all inputs are renewable.)
The hydrogen production process. For hydrogen production, HydroMax uses a two-step process that combines two conventional industrial process technologies in a single reactor vessel.
|The basic HydroMax hydrogen production cycle. Click to enlarge.|
The first stage uses steam in contact with molten iron to form iron oxide and release hydrogen. The hydrogen is not commingled with carbon monoxide or other gases—as a result, separation costs are eliminated.
In the second stage, carbon is added to reduce the iron oxide back to pure metal—a typical metal smelting method. The inputs are steam, oxygen and carbon; the outputs are hydrogen, steam, carbon dioxide, and co-generated electricity.
Iron is not consumed in the process, and remains molten whether in oxide or metal form. The iron acts as a carrier for the oxygen from one part of the process to the other. After some experimentation, Alchemix selected a mixture of iron and tin. Iron strongly attracts the oxygen in steam to form iron oxide. The tin does not oxidize but allows operation at lower temperatures and helps to remove sulfur at low cost.
Both production and reduction process steps occur in the same reactor at the same temperature (1,250º C), eliminating the need to move, cool or heat the metal bath. Alchemix worked with Rio Tinto and HIsmelt to adapt a smelting reactor to be its HydroMax vessel.
A HydroMax production plant will require two or more reactors operating in tandem to produce hydrogen continuously—i.e., when the first reactor is in the first hydrogen production stage, the second reactor will be in the second iron oxide reduction stage.
|The tailored syngas production cycle. Click to enlarge.|
The syngas production process. The Fischer-Tropsch process requires carbon as well as hydrogen in the syngas used as an input. To tailor HydroMax for syngas production requires the injection of a hydrocarbon together with steam in the first stage.
By measuring and controlling the amount of steam and hydrocarbon with on-line analyzers and controllers, a tailored syngas can be produced, and then routed to the Fischer-Tropsch reactor.
Carbon dioxide and emissions. On a total output basis, Alchemix calculates that HydroMax emits 16.3 pounds of CO2 per pound of hydrogen produced, while Steam Methane Reforming emits 9.9 pounds of CO2 per pound of hydrogen.
In the basic hydrogen production process, however, the hydrogen and carbon dioxide streams are never co-mingled, allowing a HydroMax plant to capture CO2 at a cost that is an order of magnitude lower than that associated with carbon capture for alternate methods of production, according to the company.
As to other emissions and residues:
Particulates in the gas stream exiting the reactor are captured in a baghouse.
Sulfur dioxides in the exhaust gas stream are removed in a state-of-the-art scrubber
Mercury is removed with activated carbon.
Ash-forming minerals associated with the carbon source are dissolved into the slag layer within the HydroMax reactor.
The slag is tapped periodically and quenched to become a pozzolanic material, which can be used as a replacement for Portland cement.
Alchemix began working on the HydroMax technology in 2000. Since that time, Alchemix Corporation has built several small pilot systems and developed its Hydromax reactor. It has yet to run an integrated pilot plant on a sustained basis to confirm current design, operating assumptions and economics prior to commercialization. The company estimates it will need some $300 million in commitments over the next few years to commercialize the HydroMax technology.
Alchemix had been focusing on the construction of a hydrogen production plant at one of the oil sands upgraders in Alberta, Canada, as a likely outcome. (Hydrogen is used to upgrade the bitumen.) Now it appears that a CTL project might be a possible outcome as well.
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