CTS-9634899 Sloan, E.D. Colorado School of Mines PROJECT SUMMARY A new state-of-the-art protoype for hydrate experiments is proposed by measurements of the hydrate phase structure and composition, using Raman and NMR spectroscopy. In this work we propose to do the following six things: 1. Measure the relative cage occupancies of 129Xe and 13C (methane) in sI hydrate via NMR, for calibration with data of Ripmeester and our Raman work, 2. Use the hydration numbers and cavity occupation measured via NMR and Raman methods to assess the van der Waals and Platteeuw statistical theory, 3. Determine the kinetics of solid phase transitions between hydrate structures( e.g. sI to sH ) using our existing 400 MHz NMR, and a new Raman instrument, 4. Design, fabricate, and test a new type of apparatus which combines a Raman devices (to measure the solid) with a regular macroscopic phase equilibria instrument, 5. Assess the viability of Raman spectroscopy for kinetic hydrate studies, and 6. Assess the viability of a Fiber Optics Raman device as an in-line hydrate monitor. The work will have three major impacts: 1. The hydrate structure is virtually never measured but predicted. There are multiple instances in which the incorrect hydrate structure has been predicted. With at least three common hydrate structures, the incorrect structure(and associated formation conditions) is predicted more frequently than commonly realized. The proposed work will demonstrate how this problem may be corrected. 2. The hydrate phase composition( cavity occupation, guest-to-host and guest-to-guest ratios) is also predicted rather than measured. However, such measurements are necessary to correct the existing thermodynamic model since hydrate formation conditions depend not only on structure but also on the phase composition. 3. The advent of Fiber Optics technology enables measurement of hydrate phase composition simultaneously with the macroscopic measurements of phase equilbria. This technology not only has the potential to change the method of hydrate measurements in the laboratory, it also has the potential to be used as an in-line monitor for hydrate formation in process streams. To date industry only has pressure drop to determine the initiation and growth of hydrate in a pipeline. The proposed work should be done now in our laboratory because: 1. We have experimentally validated the concept of the Raman measurement of hydrate structure and guest composition for sI, sII, and sH. 2. A recent NSF matching-funds equipment grant has provided a 400 MHz NMR instrument capable of solid or liquid measurements. 3. We have expert personnel available to supervise the work. Mr. Ben Bloys (ARCO) will be industrial liaison with our consortium of 10 companies to the project. Dr. Bob Burruss. (USGS) will provide Raman expertise and apparatus availability. Dr. John Ripmeester will act as an adjunct professor in supervising the proposed NMR work.
