Coal & Coal Biomass to Liquids
Alternate Hydrogen Production
In the Alternate Production technology pathway, clean syngas from coal is converted to high-hydrogen-content liquid hydrocarbon carriers, alcohols, or methane (“substitute natural gas or SNG). After syngas from gasification is cleaned of sulfur and other impurities, Fischer-Tropsch catalysts can be used to cause the hydrogen and carbon in the syngas to combine to form a variety of hydrocarbon molecules, and the composition of the product can be adjusted by changing process conditions. By further changes in process conditions and catalysts, alcohols such as methanol, or SNG can be produced.
These products have the benefit of being deliverable through our existing fuel distribution infrastructure and reformed to provide hydrogen near the point of use, thus providing a potential acceleration of hydrogen market penetration until hydrogen pipeline systems are installed. The evaluation and identification of these alternate pathways are an important part of this RD&D program. Computational studies and analyses are expected to play a key role in identifying promising reaction chemistries and chemical processing routes.
While Fischer-Tropsch technology for producing liquid fuels from coal has been commercialized in South Africa, further cost reductions and improvements in environmental performance, particularly CO2 capture, are necessary to surpass economic hurdles for application in U.S. markets. Studies are needed to identify the most optimal hydrogen-rich, synthesis gas-derived liquid fuel that can be used for hydrogen generation at sub-central or distributed hydrogen production sites. To be effective hydrogen carriers, synthesis gas-derived liquids and SNG must be produced, delivered, and converted into hydrogen in an efficient manner that overrides the number of energy-using steps required to provide the hydrogen. These systems require improvements in reactor design and advanced catalysts. SNG production processes need to be optimized to improve process efficiency and operations.
Current, small-scale, distributed reformer technologies are currently too expensive to supply hydrogen at a cost comparable to that of gasoline. An alternative plant could be a sub-central reformer. Multiple-unit operations and insufficient heat integration contribute to large, costly production and purification subsystems. Improved reforming and shift catalysts are needed to reduce side reactions and improve performance, bearing in mind the availability of the catalyst materials. Operating and maintenance costs are too high for distributed hydrogen generation plants that use hydrogen-rich, synthesis gas-derived liquids as feedstocks. Small-scale, distributed generation and sub-central reforming of fossil fuel-derived liquid fuels will emit greenhouse gases. Cost-effective capture of CO2 from distributed generation facilities is more difficult than at central locations.
Some of the significant RD&D issues for this pathway are:
- Studies must be completed, including computational chemistry analysis, to identify the most optimal hydrogen-rich, synthesis gas-derived liquid that can be used for hydrogen generation in sub-central or distributed hydrogen production.
- Improvements are needed in reactor design and advanced catalysts.
- Integrated operation of the coal-to-syngas with the hydrogen-rich liquids production process has to be demonstrated at commercial-scale. Use of hydrogen-rich liquids derived from synthesis gas needs to be demonstrated in reforming/fuel cell systems to confirm their suitability as hydrogen carriers.
- SNG production processes need to be optimized to improve process efficiency and operations.
- Improved processes that require less operator control and maintenance are needed.
- Research is needed to discover potential options to sequester CO2 from distributed generation systems.
Goal and Milestones – Alternate Hydrogen Production Pathway
Goal: By the end of 2013, optimize, integrate and make available an alternative economic and environmentally responsive hydrogen production pathway and reforming system to produce decentralized hydrogen.
- By the end of 2010, hydrogen-rich liquid fuels and SNG from coal technologies are feasible as an alternate hydrogen from coal production pathway and are able to meet the hydrogen cost target.
- By the end of 2013, optimize, integrate and make available an alternate hydrogen production pathway and reforming system to produce decentralized hydrogen.
Accomplishments and Current Activities
FE has a long history as a leader in researching, developing, and demonstrating the production of liquid fuels from coal-derived synthesis gas. FE’s RD&D program has included the Liquid Phase Methanol (LPMEOH) demonstration project, a DOE Clean Coal Technology Demonstration Program project. Air Products and Chemicals, Inc. (APCI) was the lead on the $213-million project, which demonstrated commercial-scale production of methanol and dimethyl ether (DME) from coal-derived synthesis gas. The project produced nearly 104 million gallons of methanol, subsequently used by Eastman Chemical as the basis for producing a variety of chemical products.
Co-production of Electric
Power and FT Liquids
Waste Management Processors, Inc.
The project will convert more than 4,700 tons per day of anthracite coal waste into electric power and more than 5,000 barrels per day of liquid fuels.
Until recently, DOE has been funding the LaPorte Alternative Fuels Development unit (AFDU) located at LaPorte, Texas and operated by APCI. This unit utilized simulated coal-derived synthesis gas to produce zero-sulfur FT liquid fuels, DME, and alcohols and successfully demonstrated liquid phase water gas shift. More recently, as part of the Clean Coal Power Initiative (CCPI), Waste Management and Processors, Inc. and its partners were selected to perform a six-year project to convert coal waste into electric power and clean, synthesis gas-derived liquid fuels (see box at right). This fuel could eventually serve as a significant early source of hydrogen for an emerging hydrogen economy.
Current R&D activities in this pathway are addressing the following objectives:
- Develop computational and analytical tools to simulate hydrogen-rich, synthesis gas-derived liquid fuels and SNG production to determine the optimum processes, and to simulate the separation of hydrogen from hydrogen-rich, synthesis gas-derived liquid fuels and SNG in sub-central or distributed production facilities.
- Develop novel reactor and catalyst systems to produce the most optimal, hydrogen-rich, synthesis gas-derived liquid fuels for reforming applications.
- Develop and optimize advanced SNG production technologies.
- Optimize sub-central production and distributed reformers for hydrogen-rich, synthesis gas-derived liquid fuels and SNG.
- Demonstrate reforming of the most optimal, hydrogen-rich, synthesis gas-derived liquid fuels and SNG in sub-central and distributed reforming applications.
Specific R&D projects are listed in the following table.
Other program elements within Hydrogen & Clean Fuels Technology include the following: