Experimental Measurement of Hydrate Numbers for Methane and Ethane and Comparison with Theoretical Values

Abstract

Hydrate numbers, n, were directly determined by two methods using a new apparatus, designed to alleviate the occlusion of liquid water in the hydrate crystal and to operate up to 15,000 psi in order to evaluate the pressure dependence of the hydrate composition. Experimental conditions for ethane were 1 18.0 psia at 40.0°F, 119.4 psia at 40.2"F, and 225 psia at 48.9"F. The experimental ethane hydrate numbers were from 7.90 to 8.46 with an average maximum relative uncertainty of &4.24/,. Four sets of experimental conditions were used for methane hydrate: 1030 psia at 5O.O0F, 1032 psia at 50.1 OF, 1901 psia at 59.9"F, and 1902 psia at 60.0"F. The experimental hydrate numbers were from 5.84 to 6.34 with an average maximum relative uncertainty of =t 1 5.6y0. Predictions for n from the solid solution theory of van der Waals and Platteeuw are discussed.

Prediction of CH4 and CO2 hydrate phase equilibrium and cage occupancy from ab initio intermolecular potentials

“…It equals the difference of enthalpy between the empty hydrate and ice, 1300 J/mol, plus the latent heat of water, Ϫ6009.5 J/mol. Roberts et al (1940) 259-286 16-108 5 Deaton & Frost (1946) 262-286 18-98 18 Kobayashi & Katz (1949) 295-302 340-775 4 Mcleod & Campbell (1961) 285-302 96-681 9 Marshall et al (1964) 290-320 160-4000 20 Jhaveri & Robinson (1965) 273-294 26-286 8 Galloway et al (1970) 283-289 71-131 4 Verma (1974) 275-291 30-186 7 Falabella (1975) 149-193 0.05-1.01 6 de Roo et al (1983) 273-286 27-100 9 Thakore & Holder (1987) 275-281 28-61 6 Adisasmito et al (1991) 273-286 27-106 11 Makogon & Sloan (1994) 190-262 0.8-18 6 Mei et al (1996) 274-285 30-90 12 Nakano et al (1999) 305-320.5 980-5000 16 Yang et al (2001) 276-286 36-97 10 Jager & Sloan (2001) 291-303 201-723 12 a Number of measurements. Unruh & Katz (1949) 277-283 20-45 5 Larson (1955) 257-283 5-45 45 Miller & Smythe (1970) 151-192 0.005-0.22 8 Robinson & Mehta (1971) 274-283 13-45 7 Falabella (1975) 194-218 0.25-1.01 5 Ng & Robinson (1985) 279-284 27-144 9 Takenouchi & Kennedy (1965) 283-293 45-1900 15 Adisasmito et al (1991) 274-283 14-44 9 Dholabhai et al (1993) 273-279 13-25 4 Englezos & Hall (1994) 275-283 15-42 6 Breland & Englezos (1996) 275-280 16-30 3 Nakano et al (1998) 289-294 1000-3300 13 Fan & Guo (1999) 273-283.6 13-129 13 Wendland et al (1999) 271-283 10-45 9 Seo & Lee (2001) 274-283 15-45 5 a Number of measurements.…”

“…Quite a few experimental data sets are reported for the Kobayashi and Katz (1949), 3: McLeod and Campbell (1961), 4: Marshall et al (1964, 5: Nakano et al (1999), 6: Jhaveri and Robinson (1965), 7: Verma (1974), 8: Yang et al (2001), 9: Roberts et al (1940, 10: Deaton and Frost (1946), 11: Galloway et al (1970), 12: Thakore and Holder (1987), 13: Adisasmito et al (1991), 14: Makogon and Sloan (1994), 15: Mei et al (1996), and16: de Roo et al (1983). Deaton and Frost (1946), 2: Unruh and Katz (1949), 3: Takenouchi and Kennedy (1965), 4: Robinson and Mehta (1971), 5: Ng and Robinson (1985), 6: Nakano et al (1998), 7: Fan and Guo (1999), 8: Larson (1955), 9: Adisasmito et al (1991, 10: Dholabhai et al (1993), 11: Englezos and Hall (1994), 12: Breland and Englezos (1996), 13: Wendland et al (1999), and 14: Seo and Lee (2001).…”

Enthalpy of dissociation and hydration number of methane hydrate from the Clapeyron equation

“…The volume change for reaction (1a) is Galloway et al [12] Deaton and Frost [6] Kobayashi and Katz [13] McLeod and Campbell [14] Verma [15] de Roo et al [16] Thakore and Holder [17] Adisasmito et al [18] Makogon and Sloan [7] DV 1a ¼ 1 À…”

Phase equilibria of clathrate hydrates of methane+carbon dioxide: New experimental data and predictions

“…Hachikubo et al [2] reported three hydrate dissociation data for 0. 25 Adisasmito et al [3] reported their hydrate dissociation data generally at temperatures near the ice point though some of their data are at higher temperatures. A summary of the experimental data reported in the literature for the hydrate dissociation conditions of methane + carbon dioxide binary gas mixtures in the presence of water is given in Table 1.…”

“…(♦); Ref [24]. ( ); Ref [25]. ( ), thermodynamic model[18] predictions assuming sI (solid line) and predicted pressure using Eq.…”