Research Terms
Mechanical Engineering Aerospace Engineering
This reactor produces high-purity hydrogen with inputs of readily available coal gases and water using a magnetically stabilized iron/silica porous structure, increasing efficiency and lowering production costs. Hydrogen is an energy-dense, clean fuel that releases only water upon combustion. The most common fuel for fuel cells, high-purity hydrogen is an essential element for making green liquid fuels (such as methanol) for combustion engines. Production of low-cost, high-purity hydrogen can help prevent energy crises and limit the spread of environmental pollutants. Although it is the most abundant chemical element in the universe, hydrogen is not available for immediate use as an energy source. It is possible, however, to liberate hydrogen gas from water and then immediately trap it from reactive metals at high temperatures via a chemical looping process that uses coal gases to enable the process to progress in a cyclic manner. Coal gasification converts raw coal into methane and syngas (a mixture of hydrogen and carbon monoxide also called coal gas). Chemical looping then produces high-purity hydrogen using steam in the oxidation step, and syngas in the reduction step. Highly concentrated carbon dioxide suitable for sequestration is produced during the reduction step, and the recovered reactive material is ready for the oxidation reaction in the next cycle. Researchers at the University of Florida have improved on the stability, reactivity, and efficiency of hydrogen production via the looping process by developing magnetically stabilized reactor beds that split water and are regenerated using coal derived syngas.
A device that inexpensively isolates clean hydrogen gas for energy from abundant water resources using coal-based syngas as an input
University of Florida researchers have developed a unique, high-porosity, magnetically stabilized iron/silica structure that can be used to produce high-purity hydrogen at high temperatures with significant throughput using an established iron-based chemical looping process. By applying an external magnetic field to stabilize fluidized iron/silica particles, the researchers can create natural spaces between the iron particles in order to exploit sintering. These spaces expand the surface area with which the gas can maintain contact during the necessary chemical reactions at high temperatures. These high porosity, very well controlled sintered structures are prepared in such a way that they maintain their shape during the hydrogen production looping processes at high temperatures. The system, which boasts improved hydrogen output, is compatible with standard methods for carbon capture and storage. This same reactor technology can also be used with carbon-neutral solar-based hydrogen production.
This sinter-resistant reactor system enables efficient and sustainable storage and release of high-quality solar energy, and can operate effectively at temperatures above 1150°C (2102°F). Concentrated solar power (CSP) is a rapidly growing market, with a global value of $10.2 trillion through 2020, and a comparative annual growth rate of 60 percent. However, to reach the Department of Energy’s target cost of $0.05/kWh for solar energy by 2030 – a rate that might allow it to compete with fossil fuels for global energy production – a transformative discovery is necessary. Current solar thermochemical energy storage compounds tolerate moderate amounts of heat (500-1000°C) and are vulnerable to sintering which steadily depletes the compounds available for solar energy storage. The sintering process requires frequent replacement of the expensive storage compounds to maintain efficiency of the solar energy reactor system.
Researchers at the University of Florida have developed a thermochemical energy storage system – strontium carbonate mixed with strontium zirconate – capable of tolerating extreme heat (above 1150°C) without significant loss of efficiency. This system can repeatedly capture and store high-quality solar energy during the day, and rapidly release energy for electricity production during the day and at night.
Sinter-resistant reactor system provides efficient high-temperature storage and on-demand release of solar energy
This reactor system utilizes solar thermal energy to facilitate endothermic decomposition of strontium carbonate (SrCO3). Resulting chemical compounds are stored separately, and then mixed as needed for on-demand generation of electrical power via a heated fluid and turbine method. The chemical equilibrium is regulated by solar heat, thus eliminating the need for coolant catalysts. The decomposition and exothermic reaction of strontium carbonate does not yield significant side products. Strontium carbonate is highly resistant to sintering through repeated cycles of power generation – this resistance is enhanced by mixture with strontium zirconate (SrZO3) compounds to maintain efficiency of the power generation process.
