Gasification Systems - Closely Aligned Programs
Applied Research Programs
Applied Research Programs that rely on use of the syngas produced by the Gasification Systems program include:
Development of effective hydrogen separation membranes is essential to strategies for the capture and sequestration of carbon dioxide for reduction of greenhouse gas emissions. The Gasification Systems and Hydrogen from Coal areas are cooperating closely with the Carbon Capture program to develop these technologies include:
Click here for more information on NETL Carbon Capture Program.
Solid Oxide Fuel Cells
Achieving IGCC plant efficiency targets in the 2015 to 2020 time frame is expected to require the incorporation of fuel cell technology as a topping cycle. That is, a fuel cell fueled by syngas or by the hydrogen component of syngas would drive the primary electrical generator directly (topping cycle), while a secondary turbine and generator would be driven by residual steam from the gasification process (bottoming cycle). In such a configuration, the fuel cell would take the place of the gas turbine used in a conventional IGCC plant.
Fuel cell development work at NETL was initiated with natural gas as the primary fuel. As fuel cell technologies have progressed, adaptation for use with either syngas or hydrogen from gasification systems has become an integral part of the R&D plan, thus interfacing the two technology areas. As in the turbine area, the interface between gasification and fuel cells occurs with the delivery of syngas from the gasification and gas cleaning systems to the fuel cell part of the plant. Susceptibility of the fuel cell components to the contaminants in the syngas is a concern that influences performance and design requirements for both technologies. Integrated power generation systems incorporating fuel cells are likely to be fueled by hydrogen produced in near-zero emissions plant, so the interaction of three program areas (Gasification Systems, Hydrogen from Coal, and Solid Oxide Fuel Cells) is important to achieving successful technology deployment.
Click here for more information on NETL Solid Oxide Fuel Cells Programs.
Hydrogen from Coal
Gasification represents the most promising approach for production of hydrogen fuel from coal, as well as for the next generation of coal-based power plants. The Gasification Systems program is responsible for providing economically competitive syngas (primarily carbon monoxide and hydrogen), while the Hydrogen from Coal program is responsible for developing processes to economically: 1) Separate hydrogen from carbon dioxide to make pure hydrogen, and 2) Make liquid fuels from the clean syngas.
- Hydrogen Production: A commercial process — the water-gas-shift reaction — chemically replaces each carbon monoxide molecule in the syngas with one hydrogen molecule and one carbon dioxide molecule, thereby creating more hydrogen. The challenge is then to economically separate the hydrogen and carbon dioxide.
- Liquid Fuels: The production (or co-production along with electricity) of clean liquid fuels requires delivery of ultra-clean syngas from the gasification section of the plant. The completely developed process, including syngas production, must be able to compete economically with conventional processes, such as those used in oil refineries.
The Gasification Systems and the Hydrogen from Coal programs are jointly supporting development of projects (including membranes) to separate hydrogen from carbon dioxide at high temperatures to reduce cost and increase efficiency. (Conventional gas separation is done at cold or cryogenic temperatures.) Membrane development is also being pursued in combination with the water-gas-shift reaction.
Shared projects include:
Click here for more information on NETL Hydrogen from Coal Program.
One of the most promising applications of gasification is Integrated Gasification Combined Cycle (IGCC). IGCC systems typically: 1) Convert solid feedstock (such as coal) into a clean syngas, 2) Burn the syngas to drive a gas turbine, and 3) Use the still-hot exhaust from the gas turbine to make steam, which is used to drive a steam turbine. This efficient integrated system for power generation was created originally for firing with natural gas. Effective deployment of IGCC systems requires close coordination and integration of the gasification and turbine areas and their separate requirements.
Other important areas of interaction between gasification and turbines are co-production (the simultaneous production of electricity and hydrogen, liquid fuels, and/or chemicals); hydrogen-powered turbines; and the capture of carbon dioxide. For co-production to reach optimum value, the various processes must be tightly integrated. For instance, hydrogen-powered turbines making electricity could be combined under the purview of the Hydrogen from Coal program with the production of high-purity hydrogen for other uses — a potentially appealing combination because lower-purity hydrogen can be burned in the turbine, while much higher-purity hydrogen is required for use in either fuel cells or chemical production. Some of the more efficient hydrogen production processes produce both high- and lower-purity hydrogen.
Hydrogen-based and co-production clean-fuel applications both require oxygen-blown gasification. The Gasification Systems program is developing an innovative ion-transport membrane (ITM) oxygen separation unit that has passed proof-of-concept testing and is now undergoing pilot-phase scale-up to pre-commercial operation. Turbine integration to provide inexpensive preheating of the air input to the ITM is a critical part of the vision for the ITM technology.
Shared projects include:
Click here for more information on NETL Hydrogen Turbine Program.