DOE - Fossil Energy Techline - Issued on: May 13, 2003
From Coal to Chemicals...
Successful Clean Coal-to-Methanol Project Boosts Prospects For "Multi-Product" Coal Plant
Now, largely because of one of the Department of Energy's most successful Clean Coal Technology projects, in the next 35 years, the future may well be "plastics...from coal."
Air Products Liquid Phase Conversion Company, L.P., a partnership between Air Products and Chemicals, Inc. (Air Products), and Eastman Chemical Company (Eastman), has successfully completed a nearly 11-year project to demonstrate an advanced method for making methanol from coal. Eastman uses the methanol as a chemical "building block" for a wide range of consumer products, from the plastics of toothbrush handles to the celluloid of photographic film.
The 69-month government co-funded operating period ended as trouble-free as it began. Since April 1997, when the Liquid Phase Methanol (LPMEOHTM) process began its first test runs at Eastman Kingsport, Tenn. chemicals-from-coal complex, the demonstration facility has operated with a remarkable on-stream availability of 97.5 percent, the best of any of the original Clean Coal Technology projects co-funded by the Energy Department in the late 1980s and early 1990s.
During its demonstration period, the facility produced nearly 104 million gallons of methanol from coal gas with a demonstrated plant capacity in excess of 300 tons of methanol per day, more than 15 percent greater than the plant's design rate.
As a result, Eastman is continuing to use the technology to provide a portion of its chemical methanol feedstock requirements, making the project another of the Energy Department's clean coal commercial "success stories."
The demonstration effort was the result of a $213.7 million cooperative agreement awarded to the Air Products and Eastman partnership by the Energy Department. The federal government provided $92.7 million while the partnership contributed nearly $121 million. The project was one of 38 joint government-industry clean coal technology demonstration ventures funded by the Energy Department in a program originally begun during the Reagan Administration.
Besides being a current success story, the technology could also offer a preview of future coal plants. One of the Energy Department's top priorities is to develop a "multi-product" coal plant - a plant that would co-produce hydrogen and other chemical compounds simultaneously with the generation of electricity. President Bush recently announced plans to build an emission-free coal plant, named FutureGen, that would employ the "multi-product" concept.
Prior to the project, Eastman Chemical made methanol using coal or synthesis gas from its Coal Gasification Facility. The synthesis gas was reacted to methanol in a fixed catalyst bed reactor. The Clean Coal Technology project demonstrated a new and more effective way to carry out the coal gas-to-methanol synthesis step with greatly enhanced feedstock flexibility.
A joint Air Products-Department of Energy research project in the 1980s had showed how the process could be improved by suspending the catalyst in an inert mineral oil and bubbling the coal gases through the slurry.
The "slurry bubble column" offered several advantages to the gas phase process. The mineral oil helps dissipate the heat created by the synthesis gas-to-methanol reaction, helping protect the catalyst and prolonging its life. The liquid phase process is also capable of processing a wide variety of feedstock gases from a coal gasifier more efficiently, converting more of the gas to methanol per pass than its conventional counterpart. Moreover, the methanol produced was a higher quality product - generally greater than 97 percent pure with only one percent water by weight when high carbon oxides feedstocks are used. The gas-phase process, by contrast, generally yields a methanol product containing from 4 to 20 percent water by weight and requires a balanced gas feedstock (a unique stoichiometric ratio of carbon oxides and hydrogen).
On December 19, 1989, the Energy Department announced that a proposal by Air Products to scale up the LPMEOHTM process to full commercial size had been selected for government co-funding. A cooperative agreement, outlining plans for the project and government-industry cost-sharing arrangements, was awarded on October 18, 1992. Plant construction began in October 1995.
The first production of methanol occurred on April 2, 1997, and stable operations were achieved only four days later. During a key part of the demonstration phase, from 1998 through 2000, the plant's operational reliability topped 99 percent.
Aside from providing a chemical feedstock for Eastman, some methanol from the demonstration unit was made available to seven test locations to study whether coal-derived methanol, free of sulfur and other impurities, could replace petroleum in transportation, or be used as a peaking fuel in combustion turbines, or supply a source of hydrogen for fuel cells. Test results indicate that stabilized (as-produced) methanol from the process can be used directly in fuel flexible vehicles, gas turbines, and diesel generators with little to no penalty on performance or fuel economy. However, purification of the methanol (similar to gas-phase systems) is needed if it is to be a source of hydrogen for a phosphoric acid fuel cell.
Successful demonstration of the LPMEOHTM technology, and the application of methanol to transportation and power generation systems, adds significant flexibility and dispatch benefits to integrated gasification combined cycle electric power plants. These facilities have traditionally been viewed as strictly baseload power generation technology. Now, central clean coal technology processing plants, making coproducts of electricity and methanol, could simultaneously meet the needs of local communities for dispersed power, transportation fuels and manufactured chemical products.
For more information, contact:
Technical Information Contacts
Air Products and Chemicals Inc.:
Eastman Chemical Company: