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University of Wyoming

UW Technologies Available for Licensing
 

Various Technologies: Plasma Reactors for Gas Decomposition with Advanced Membranes for Hydrogen Recovery


THE PROBLEM
H2S is produced in large quantities as a byproduct of a number of chemical reactions particularly in the methane and petroleum industries. For example, H2S is generated during various refining processes to “sweeten” crude oils and encourage necessary precipitation of elements such as sulfide ores in metal refining operations. Just one typical oil refinery regularly produces over 1000 tons of H2S per day!

Because of its dangerous nature, H2S generally requires extensive, expensive, and complex treatment to be processed into a safe form – often involving the Claus process, sponge iron adsorption, or liquid adsorption scrubbing.

The H2S treatment program on-going at the University of Wyoming is working on ways to efficiently process large amounts of H2S without many of the complexities and costs associated with current treatment methodologies. In addition, our treatment program allows for the simultaneous recovery of valuable hydrogen (H2), which has many uses today and in tomorrow’s hydrogen economy.

While most of our work involves H2S, we have a substantial effort on-going for NOX and methane processing as well.

PROJECT DESCRIPTION
This experimental research project is actively designing, building, and testing reactors for efficient hydrogen sulfide (H2S) decomposition. As an integral part of the reactor design, advanced membranes are being developed to selectively recover hydrogen from the reaction products. The reactors produce a non-thermal plasma in which the H2S is dissociated into sulfur and hydrogen ions and atoms. Hydrogen will then be recovered within the reactors through superpermeable multi-layer membranes designed for plasma driven permeation of hydrogen atoms. Superpermeability of atomic hydrogen has been reported by several researchers using membranes constructed of niobium, tantalum, vanadium, and their alloys. The multi-layer membranes are designed to include a superpermeable metal layer, coated with a corrosion resistant layer on the surface exposed to the plasma reaction, and a hydrogen atom recombination layer on the opposite surface to promote molecular hydrogen formation and desorption.

The project goal is to develop an energy efficient process capable of decomposing H2S with simultaneous hydrogen recovery using the selective membranes. Both the reactors and membranes are intended to be robust for industrial application. Successful development of the reactor and membrane technology could be applied in any industry that produces hydrogen sulfide, including natural gas sweetening plants and petroleum refinery hydrodesulfurization or acid gas processing units. The system is designed to be a viable alternative to the Claus process for H2S treatment, with the advantage of recovering hydrogen as a pure product instead of directly converting it to water, as in the Claus process. In concept, complete H2S conversion can be obtained without the need for expensive tail gas clean up steps. Compact design and flexible operating parameters are anticipated to permit application in remote locations and to provide convenient scale-up for larger processing units. The high purity hydrogen product could be used for fuel cell or other fuel applications or as a chemical feedstock.

The research is currently funded by the Department of Energy National Energy Technology Laboratory and the University of Wyoming. Additional funding is sought to build more advanced reactors and to improve the membrane production techniques. Remaining technical challenges include improvement of the reactor electrical efficiency and optimization of both the reactor and membrane design with the reactor operating parameters to enhance superpermeable membrane operation.

Past and present research at the University of Wyoming has employed similar pulsed corona plasma reactors to convert methane to higher hydrocarbons plus hydrogen and to decompose NOx. This previous experience offers potential synergies that could include multi-component gas processing with selective conversion of undesired, low-value, or toxic components.

INTELLECTUAL PROPERTY
The University of Wyoming has aggressively protected our treatment process by filing and prosecuting U.S. and international patent applications on the following technologies:

•  01-001 Apparatus and Method for the Production of Methanethiol, 6,995,288

•  02-031 Membrane for Hydrogen Recovery from Streams Containing Hydrogen Sulfide, WO03101588A1.pdf;

•  03-007 A Novel Process for the Manufacture of Hydrogen Cyanide and Acrylonitrile with Simultaneous Recovery of Hydrogen WO2004/026462

RESEARCH FACILITIES
In 2003, the University of Wyoming constructed a 1500 square foot laboratory dedicated for this project. The laboratory has ample utilities and is designed to meet stringent safety requirements. Existing research equipment includes a co-axial cylinder corona discharge reactor, pulsed with a thyratron switch. The moderately-sized pilot scale reactor can process up to ~100 standard cubic feet of gas per hour. The design is modular, which should permit convenient scale-up for commercial applications. In additions, this research reactor has been designed with a number of adjustable parameters, including pulse frequency (up to 1000 Hz), charge voltage (15-25 kV), capacitance (640-2560 pF), pressure (0-65 psig), temperature (ambient-350°C) and flow rate (5-100 standard cubic feet per hour). Further, the electrode material can be easily changed to accommodate new membrane designs. An on-line mass spectrometer is used to analyze the product gases to measure product distributions and to quantify conversion.

KEY RESEARCH PERSONNEL
The project is being led by a team of experienced researchers in the Chemical and Petroleum Engineering and the Electrical and Computer Engineering Departments of the University of Wyoming. The Chemical and Petroleum Engineering Department is providing the process operation and membrane design expertise. The process team is led by Assistant Professor Morris D. Argyle, who holds a Ph.D. in Chemical Engineering from the University of California at Berkeley. His research specialty is reaction kinetics and heterogeneous catalysis. He has eight years of industrial experience as a B.S. chemical engineer in the petroleum refining industry. Membrane fabrication is being led by Adjunct Professor John F. Ackerman, who holds a Ph.D. in Physical Chemistry from Brown University. He works for General Electric Corporation at their Aircraft Engine division in Cincinnati, OH, but spends approximately one fourth of his time at the University of Wyoming. He has extensive experience in materials processing involving chemical and physical vapor deposition techniques used to manufacture the hydrogen membranes. The electrical design of the reactor is being conducted by a team of professors in the Electrical and Computing Engineering Department: Associate Professor Suresh Muknahallipatna, who received his Ph.D. in Electrical Engineering from the University of Wyoming; Associate Professor Jerry C. Hamann, who received his Ph.D. in Electrical Engineering from the University of Wisconsin at Madison; and Professor Stanislaw Legowski, who received his Ph.D. in Electronics Engineering from the Technical University of Gdansk. The mechanical design and construction of the reactors is being led by Senior Engineering Technician Ronald Borgialli in the Chemical and Petroleum Engineering Department.

CONTACT INFORMATION
If your company would like to learn more about this technology and how your company may help us develop it or apply it in commercial situations, please contact the director of the University of Wyoming Research Products Center, Davona Douglass.