HR: 1340h
AN: OS23A-1032    [Abstracts]
TI: Guest Chemical Composition as a Significant Parameter for Hydrate Interpretation
AU: * Osegovic, J P
EM: josegovic@mdswater.com
AF: Marine Desalinations Systems, L.L.C., 1601 3rd St. South, St. Petersburg, FL 33701, United States
AU: Max, M D
EM: mmax@mdswater.com
AF: Marine Desalinations Systems, L.L.C., 1601 3rd St. South, St. Petersburg, FL 33701, United States
AB: Each guest in compound hydrate has both independent and co-dependent links to formation and dissociation processes. At the simplest level, compound hydrate can be modeled as a single entity that grows at a fixed composition, for example, the case where an infinite reservoir of gas is exposed to a limited quantity of water. In real systems, the rate at which reactant guests are brought to the formation region will often be the limiting process and an infinite gas supply cannot be assumed. Under these conditions compositional changes that occur during formation lead to multiple hydrate formation processes, some of which are concurrent but others which are sequential. Longer time scales (but relatively short on the geologic time scale) can lead to redistribution of materials to their lowest energy states: it looks like an infinite supply of gas caused the hydrate to form, but one cannot accurately back predict the original gas phase based only on the hydrate composition due to selective uptake processes. One must understand the formation/composition history to understand the current state. Dissociation processes can also be complex. These processes include selective release of guests, and restabilization due to changes in the concentration of supporting solutions. For example, bleaching of select formers occurs when hydrate is exposed to an under saturated fluid stream. In some cases these composition changes can lead to azeotrope-like behavior, while in others complete loss of certain guests can occur.
DE: 0714 Clathrate
DE: 1011 Thermodynamics (0766, 3611, 8411)
DE: 3004 Gas and hydrate systems
DE: 3620 Mineral and crystal chemistry (1042)
DE: 5410 Composition (1060, 3672)
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting