Hydrates at high pressures: Part I. Methane‐water, argon‐water, and nitrogen‐water systems

Abstract

qi,qz,qi,qz = General quantities given by Equation (S), SM' = S M / d R = r = rt = a = rm = s = T = T = Ti = Tz = N T~ = -NTa* = .. v * A Part I ratio of cylinder speeds radius or coordinate radius of inner cylinder radius of outer cylinder mean radius shape function given by Equation (23), Part I temperature average temperature in annulus temperature of inner cylinder temperature of outer cylinder Taylor number Tavlor number ( \ i N~a " __-N T~~ = t = tl= u = u 1 = us = o = 0 1 = o = -. w = w1 = z = z = , . NTac* = crkcal Taylor number critical Taylor number ( \ / N T u~* ) time first harmonic component of temperature disturbance velocity in r direction first harmonic component of u disturbance velocity at edge of boundary layer velocity in 8 direction. first harmonic component of o disturbance average velocity of flow in potentially unstable region of annulus velocity in z direction first harmonic component of w disturbance constant given by Equation ( 2 2 ) , Part I coordinate Greek Letters (Y = dimensionless constant @ = constant in Equation ( l l ) , Part I p1 = coefficient of voIume expansion 6 = potentially unstable region of gap SM = momentum boundary-layer thickness 8T = 6 T 1 = v = r = e = A = m = a = a1 = nz = thermal boundary-layer thickness kinematic viscosity dimensionless coordinate coordinate dimensionless wave length dimensionless constant given in Equation ( 13), 6 T / d -Part I meed of rotation of cylinder (rad./sec.) r k i o n a l speed of kner cylinder rotational speed of outer cylinder LITERATURE CITED 1. Becker, K. M., and J. Kaye, Am. Soc. Mech. Engrs. Paper 2. Bjorklund, I . S., and W. R4. Kays, Am.A gas hydrate may be defined as the stable crystalline icelike complex formed from the lower molecular weight nonpolar and slightly polar compounds and water when a mixture of these is subjected to external pressure. Gas hydrates may occur above and below the ice point and fall in a subdivision of the class of compounds known as inclusion compounds.The first hydrate of this type, chlorine hydrate, was discovered by Davy in 1810. After this discovery considerable work was done by Villard (17) and De Forcrand (9, 10) on the direct determination of hydrate formulas and formation conditions. Donald R. Marshall is with E. I. d

Thermodynamic and Raman Spectroscopic Studies of Ar Hydrate System

“…(2) shows the pressure temperature relations of Ar hydrate system accompanied with the literature values [3,18]. In the low-pressure region (up to 200 MPa), our data are in good agreement with Marshall's ones [18]. Moreover, except less than 20 MPa, the present data are in almost agreement with Dyadin's ones [3].…”

“…The region A corresponds to the pressure range up to 281 MPa. The pressure range from 281 to 456 MPa is region B, and over 456 MPa defined as region C. Especially, in the region B, the present data show the large discrepancies with the literature [3,18]. The Raman spectrum of intermolecular O-O stretching vibration mode of water molecules was detected around 210 cm -1 in the structure-II gas hydrate systems; we have already reported about N 2 and SF 6 hydrate systems [19,20].…”

“…(2). Pressure -temperature relations of Ar hydrate stability boundaries: , three-phase coexisting curve of Ar hydrate (present study); , Marshall, Saito, and Kobayashi [18]; , Dyadin, Larionov, Mirinski, Mikina, and Starostina [3]. From our experimental data (up to 485 MPa), Ar hydrate has two structural transition points located at 281 MPa and 456 MPa.…”

Organic Geochemistry of Gases, Fluids, and Hydrates at the Cascadia Accretionary Margin

“…A CO 2 -methane-water hydrate is stable at higher temperatures or lower pressures than a pure methane-water hydrate and thus could not account for an upward translation of the hydrate stability field. Likewise, at constant temperature, a natural gas-water hydrate is stable at much shallower depths than a methane-water hydrate (Marshall et al, 1964). For example, a 10% addition of ethane to a pure methane hydrate at 15°C would shift the phase boundary from 140 bar to 75 bar (Katz et al, 1959).…”

Different Mechanism Effect between Gas-Solid and Liquid-Solid Interface on the Three-Phase Coexistence Hydrate System Dissociation in Seawater: A Molecular Dynamics Simulation Study

“…Sarupria compared the MD simulations result with experimental data, and found that the difference in the melting points (T m (hydrate)-T m (ice)) that was obtained from MD simulations is in good agreement with the experimental value. Under the experimental conditions, the hydrate melting point at 30 MPa is 295 K [61], 22 K higher than the melting point of Ice Ih. The melting point of SPC model is 190 K at 30 MPa, the corresponding hydrate melting point is about 212 K. In our simulation work, the temperature range of 243 K-263 K is higher than the melting point of both Ice Ih and hydrate at 30 MPa.…”