Hydrate Dissociation Data Research Articles

Dimethyl sulfoxide as a novel thermodynamic inhibitor of carbon dioxide hydrate formation

• Dimethyl sulfoxide decreases the thermodynamic stability of carbon dioxide hydrate. • Obtained CO 2 hydrate dissociation data are reliable and thermodynamically coherent. • Phases of sI hydrate, crystalline ice I h , and solid CO 2 were identified by PXRD. • DMSO avoids inclusion into the CO 2 hydrate framework. • DMSO is an effective thermodynamic inhibitor of CO 2 hydrate formation. The paper investigates dimethyl sulfoxide (DMSO) as a promising inhibitor of gas hydrates. The equilibrium conditions of the CO 2 hydrate were measured over a broad range of temperatures (from 243 K to 283 K) and DMSO concentrations (up to 50 mass%). DMSO decreases the thermodynamic stability of the CO 2 hydrate. Thermodynamic coherence of new hydrate equilibria data was demonstrated. The sI hydrate, crystalline ice I h , and solid CO 2 phases were identified using PXRD at 143 K. Measured unit cell parameter for sI hydrate (11.86 Å) coincided with the pure sI CO 2 hydrate literature value. The DMSO inhibition activity grows much faster in water solution in comparison to lower alcohols. We explain this behavior by the more pronounced non-ideality of DMSO water solutions. Thus, DMSO can be considered an effective thermodynamic inhibitor of the formation of CO 2 hydrate, superior in anti-hydrate activity to alcohol THIs within a specific range.

Thermodynamic modeling of clathrate hydrate stability conditions in the presence of amino acid aqueous solution

The drawbacks of using chemical compounds in the oil and gas industries necessitate applying green and environmentally friendly compounds. Amino acids can be considered as a fantastic remedy to the regular widely used organic hydrate inhibitors in the gas pipelines and facilities. In the present work, hydrate stability conditions of various hydrate formers including methane, CO2, and natural gas in the attendance of a variety of amino acids (Glycine, Alanine, Serine, Valine, Proline, Arginine, Threonine, Asparagine, Phenylalanine and Histidine) aqueous solutions were theoretically studied. Two distinct approaches are considered: The van der Waals-Platteeuw (vdW-P) theory-based approach in which the activity coefficient parameters of the amino acids are available and the modified Pieroen model proposed by Dickens and Quinby-Hunt in which no information is available for the activity coefficient parameters of the amino acids. The vdW-P theory-based approach applies the solid solution theory in which, the UNIQUAC activity coefficient model is employed to calculate the water activity in the liquid/aqueous phase and the Peng-Robinson equation of state (EoS) is applied for calculation of the vapor/gas phase fugacity. The Dickens and Quinby-Hunt model preforms the cryoscopic method and relates the liquid water-hydrate-vapor/gas curve to the ice-water curve. The average absolute deviation (AAD) for the hydrate dissociation temperatures for all 333 reported hydrate dissociation data points is about 0.22 K, which is satisfactory.

Thermodynamic modeling and experimental measurement of semi-clathrate hydrate phase equilibria for CH4 in the presence of cyclohexane (CH) and tetra-n-butyl ammonium bromide (TBAB) mixture

In the current study, the effect of tetra-n-butyl ammonium bromide (TBAB) and cyclohexane mixture on CH4 semi-clathrate hydrate formation was studied. Semi-clathrate dissociation conditions for CH4 + TBAB + cyclohexane + water were investigated at different concentrations of TBAB (0.05, 0.10, and 0.15) mass fraction in the presence of cyclohexane at the pressure and temperature ranges of 1–8 MPa and 275.1–295 K, respectively. In addition, a thermodynamic model was suggested to predict the phase equilibria of our system, which is divided into four phases, where the van der Waals–Platteeuw Solid Solution Theory has been used to predict the hydrate phase. For gas phase, The SRK equation of state was applied. For oil phase, the cyclohexane activity coefficient in the organic phase was calculated by the non-random two-liquid model (NRTL). Finally, to determine the activity coefficient of the electrolyte species in the aqueous phase, the semi-empirical electrolyte NRTL (eNRTL) activity model was used. The results showed that the proposed model has an acceptable agreement with the experimental semi-clathrate hydrate dissociation data with an approximately average absolute relative deviation of 5.4%.

Use of 1-butyl-3-methylimidazolium-based ionic liquids as methane hydrate inhibitors at high pressure conditions

The performance of 1-Butyl-3-methylimidazolium chloride ([BMIM][Cl]) and 1-Butyl-3-methylimidazolium bromide ([BMIM][Br]) as methane hydrate inhibitors is evaluated in this work. New hydrate dissociation data were obtained through high-pressure calorimetry for aqueous solutions with inhibitor mole fractions of 1.0%, 5.0%, 10.0%, and 15.0% and pressures from 9.6 to 100 MPa. Challenging situations from the experimental point of view were also explored. These ionic liquids are known to be both kinetic and thermodynamic inhibitors, but they promote hydrate growth at mole fractions of 1% and 5% in the pressure range studied. The effectiveness of these ionic liquids as thermodynamic inhibitors at high pressures is compared to that of methanol, a commercial inhibitor commonly used in the oil and gas industry. [BMIM][Cl] is more effective than [BMIM][Br] and methanol, considering equimolar aqueous solutions, even though methanol is more effective for solutions with the same mass fraction.

Phase stability conditions for clathrate hydrate formation in (fluorinated refrigerant + water + single and mixed electrolytes + cyclopentane) systems: Experimental measurements and thermodynamic modelling

Phase equilibrium conditions (dissociation data) for clathrate hydrates (gas hydrates) were studied for systems involving fluorinated refrigerants + water + single and mixed electrolytes (NaCl, CaCl2, MgCl2 and Na2SO4) at varying salt concentrations in the absence and presence of cyclopentane (CP). The ternary systems for (R410a or R507) + water + CP were performed in the temperature and pressures ranges of (279.8–294.4) K and (0.158–1.385) MPa, respectively. Measurements for {R410a + water + (NaCl or CaCl2) + CP} were undertaken at salt concentrations of (0.10, 0.15 and 0.20) mass fractions in the temperature and pressure ranges of (278.4–293.7) K and (0.214–1.179) MPa, respectively. The temperature and pressure conditions for the (R410a + water + Na2SO4) system were investigated at salt concentration of 0.10 mass fraction in range of (283.3–291.6) K and (0.483–1.373) MPa respectively. Measurements for {(R410a or R507) + water + mixed electrolytes NaCl, CaCl2, MgCl2} were undertaken at various salt concentrations of (0.002–0.15) mass fractions in the temperature and pressure ranges of (274.5–292.9) K and (0.149–1.119) MPa in the absence and presence of CP, for which there are no published data related to mixed salt and a promoter. The phase equilibrium measurements were performed using a non-visual isochoric equilibrium cell and the pressure-search technique. This study was focused on obtaining equilibrium data that can be utilized to design and optimize for water desalination process and the development of a Hydrate Electrolyte–Cubic Plus Association (HE–CPA) Equation of State based model. The results indicate hydrate dissociation pressure reduction/hydrate dissociation temperature increase up to ambient conditions in the presence of promoter (CP). The experimental results were then modelled. The modelling results are in good agreement with the measured hydrate dissociation data.

Thermodynamic Stability Conditions of Clathrate Hydrates in Methane/Carbon Dioxide + Tetrahydrofuran + Cyclopentane + Water Systems: Experimental Measurement and Modeling

In this communication, experimental hydrate dissociation data for methane + tetrahydrofuran (THF) (0.03 and 0.0555 mole fractions in aqueous solution) + cyclopentane (CP) + water systems are reported in the temperature range from 294.8 to 301.3 K and pressure range from 1.91 to 4.95 MPa, which are measured using an isochoric pressure-search method. Other experimental data were collected from the literature. Then a thermodynamic model for four-phase equilibria, hydrate (H)–aqueous liquid (Lw)–organic liquid (La)–vapor/gas (V), systems composed of water, methane (CH4), carbon dioxide (CO2), and/or CP was developed. The thermodynamic model is based on the solid solution theory of van der Waals–Platteeuw (vdW-P) for the hydrate phase and Peng–Robinson equation of state (P-R EOS) for vapor/gas phase. For calculating the activity coefficient of water and THF in the aqueous phase, the universal quasichemical (UNIQUAC) functional-group activity coefficient (UNIFAC) model is also used. The Langmuir constants of TH...

Can 2-methyl-2-butene and isoprene form clathrate hydrates?

In order to establish whether 2-methyl-2-butene and isoprene can form hydrates, experimental hydrate dissociation data were measured for the following systems: methane + water, 2-methyl-2-butene + methane + water and isoprene + methane + water. An isochoric pressure search method was used to perform the measurements in the ranges of (274.6 to 288.3) K and (3.25 to 13.35) MPa. The reported results are discussed in terms of the ability of isoprene (2-methyl-1, 3-butadiene) and 2-methyl-2-butene to interfere with methane hydrate dissociation conditions. It is found that the two C5 hydrocarbons are likely not hydrate formers. However, a further confirmation via appropriate analytical tools is recommended.

Phase stability conditions of clathrate hydrates in the (methane + 3-methyl-1-butanol + water), (methane + 3,3-dimethyl-2-butanone + water) and (methane + 2,3-dimethyl-2-butene + water) systems: Experimental measurements and thermodynamic modeling

Abstract In this communication, hydrate dissociation data for methane + three liquid hydrocarbons namely 3-methyl-1-butanol, 3,3-dimethyl-2-butanone and 2,3-dimethyl-2-butene are reported. An isochoric pressure-search method was employed to generate the four-phase equilibrium data in the diverse pressure ranges (2.43–8.23 MPa, 1.73–7.56 MPa, and 2.81–7.05 MPa), respectively. The corresponding temperature ranges are (274.3–284.3 K, 277.1–288.9 K and 274.4–283.3 K), respectively. The obtained results in comparison with methane hydrate dissociation data indicate that at a given pressure, the hydrate dissociation temperature in the system consisting of methane + 3-methyl-1-butanol + water roughly equals to those in the system with methane hydrate. Although four phase hydrate dissociation data of methane + 2,3-dimethyl-2-butene + water system has not been determined to exhibit promotion effect, the reduction of hydrate dissociation pressure was observed in the methane + 3,3-dimethyl-2-butanone + water system. Furthermore, estimation of hydrate dissociation conditions of the aforementioned systems has been done by applying the van der Waals-Platteeuw type thermodynamic model and a good agreement is observed.

Gas hydrate equilibria in the presence of monoethylene glycol, sodium chloride and sodium bromide at pressures up to 150 MPa

Hydrate dissociation data for single hydrate formers are widely available, however there is a clear gap for multicomponent systems over a wide range of pressures and in presence of inhibitor or electrolytes. This data is required to validate thermodynamic models being used to predict hydrate inhibitor (monoethylene glycol (MEG)) requirements in pipelines transporting unprocessed well streams with highly concentrated formation waters and, in the case of sodium bromide, drilling fluids. In this work, hydrate dissociation temperature measurements at pressures up to 150 MPa were conducted for a multicomponent synthetic gas mixture in equilibrium with deionised water, an aqueous sodium chloride solution, mixed aqueous MEG/sodium chloride and MEG/sodium bromide solutions using the isochoric step heating method. The Soave-Redlich and Kwong – Cubic-Plus-Association equation of state combined with a modified Debye Hückel electrostatic term is employed to model the phase equilibria. The hydrate-forming conditions are modelled by the solid solution theory of van der Waals and Platteeuw. The thermodynamic model has been evaluated using these new generated hydrate data. The thermodynamic model (as implemented in our in-house software HWPVT 1.1) and experimental data are in good agreement, supporting the reliability of the developed model.

Phase stability conditions of carbon dioxide and methane clathrate hydrates in the presence of KBr, CaBr2, MgCl2, HCOONa, and HCOOK aqueous solutions: Experimental measurements and thermodynamic modelling

Experimental data on dissociation conditions of carbon dioxide clathrate hydrate in the presence of KBr, CaBr2, MgCl2, HCOONa, and HCOOK aqueous solutions, as well as methane clathrate hydrate in the presence of HCOONa and HCOOK aqueous solutions have been measured and are reported in this study. Measurements were conducted in the temperature and pressure ranges of (266.9–285.8)K and (1.47–9.68)MPa, respectively, using an isochoric pressure-search method. Results reveal that at varying concentrations, the aqueous salt solutions have a satisfactory inhibition effects on both carbon dioxide and methane hydrate formation, causing a shift in the P-T (pressure–temperature) equilibrium cruves to higher pressures and lower temperatures. A thermodynamic model based on the solid solution theory of van der Waals and Platteeuw (vdW-P) was used for estimation of hydrate dissociation conditions in the presence of the salt aqueous solutions. The gas phase was modeled using the Valderrama modification of the Patel-Teja equation of state (VPT EoS). The UNIQUAC approach, along with the Debeye-Huckel method, was applied to calculate the activity coefficient of water in the presence of salt. The UNIQUAC interaction parameters between water and anions and cations were optimized using the measured hydrate dissociation data. The model results provide a reasonable agreement with the experimental data, with an average absolute deviation (ARD%) below 0.3%.

Four phase hydrate equilibria of methane and carbon dioxide with heavy hydrate former compounds: Experimental measurements and thermodynamic modeling

We experimentally investigated the hydrate dissociation condition for four phase hydrate (H)-aqueous liquid (LAq)-hydrocarbon rich liquid (LHC)-vapor (V) for the ternary systems of help gas-heavy hydrate former-water. Methane and carbon dioxide are known as help gases and benzene and cyclohexane are considered as heavy hydrate formers. The experimental data were generated using an isochoric pressure-search method. Two different equations of state (EOS) were employed to study the equilibrium phase behavior of ternary four phase systems. The EOSs considered are Valderama-Patel-Teja EOS combined with non-density dependent mixing rule (VPT+NDD) and Statistical Associating Fluid Theory EOS proposed by Huang and Radosz (SAFT-HR). The required binary interaction parameters (BIP) were obtained using vapor-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE) data. The hydrate phase was modeled by the modification of the solid solution theory of van der Waals and Platteeuw. To obtain reliable results, distortion of cages due to occupation of large molecules was considered. The Kihara parameters of cyclohexane were adjusted to hydrate dissociation data. Model calculations for hydrate forming conditions were found to be in satisfactory agreement with the newly reported data in this work and literature data.

Experimental Clathrate Hydrate Dissociation Data for Systems Comprising Refrigerant + CaCl2 Aqueous Solutions

Hydrate dissociation data are presented for systems of refrigerants (R134a, R410a, and R507) + water + CaCl2 at varying salt concentrations. The R134a + water + CaCl2 system was measured at salt concentrations of (0, 0.358, 0.591, and 0.756) mol·kg–1 in the temperature range of (276.2 to 283) K and a pressure range of (0.125 to 0.428) MPa. The systems composed of {R410a or R507} + water + CaCl2 were measured at salt concentrations of (0, 0.358 and 0.756) mol·kg–1 in the temperature range of (274.7 to 293) K and a pressure range of (0.179 to 1.421) MPa. The isochoric pressure-search method was used for all the hydrate measurements. The data generated can be used in the design and optimization of industrial wastewater treatment and desalination processes. The presence of CaCl2 in the aqueous solutions shifts the hydrate–liquid water–vapor (H–Lw–V) equilibrium phase boundary toward lower temperatures as salt concentration increases. The experimental data were modeled using a combination of the solid solution...

Thermodynamic stability conditions of clathrate hydrates for refrigerant (R134a or R410a or R507) with MgCl2 aqueous solution

Clathrate hydrate dissociation data were measured for systems comprising of refrigerants (R134a, R410a and R507) + water + MgCl2 at varying salt concentrations. The ternary system for R134a + water + MgCl2 was measured at salt concentrations of (0.259, 0.546, and 0.868) mol.kg−1 in the temperature range of (277.1–283) K and a pressure range of (0.114–0.428) MPa. Hydrate measurements for the {R410a or R507} + water + MgCl2 systems were measured at salt concentrations of (0.259 and 0.546) mol.kg−1 in the temperature range of (274.3–293) K and a pressure range of (0.154–1.421) MPa. The isochoric pressure-search method was used to measure the hydrate dissociation data. This study is a continuation of previous investigations which focused on obtaining hydrate dissociation data for R134a, R410a and R507 refrigerants in NaCl and CaCl2 aqueous solutions. The measured hydrate dissociation data can be used to design industrial wastewater treatment and desalination processes. The results show that the effect of salt concentration on hydrate formation is smaller for MgCl2 aqueous solutions compared to CaCl2 and NaCl as salt concentration increases. Modelling of the measured data is performed using a combination of the solid solution theory of van der Waals and Platteeuw, the Aasberg–Petersen et al. model, and the Peng–Robinson equation of state with classical mixing rules. The model is in good agreement with the measured hydrate dissociation data.

Clathrate hydrate formation in (methane, carbon dioxide or nitrogen + tetrahydropyran or furan + water) system: Thermodynamic and kinetic study

Experimental hydrate dissociation pressures for (methane, carbon dioxide, or nitrogen+tetrahydropyran or furan+water) are reported in the temperature ranges of (278.8 to 299.7)K. An isochoric step-heating method was used to generate the experimental data. A comparison between the generated hydrate dissociation data for (methane+water) system in this work and corresponding data from the literature is set forth to confirm the reliability of the experimental method used herein. In order to investigate the promotion effects of tetrahydropyran and furan, the experimental results obtained for the systems containing these two chemicals are compared to some selected experimental data in their absence, reported in the literature. It is shown that both tetrahydropyran and furan have remarkable promotion effects and furan exhibits a slightly better performance. Moreover, the reliability of the literature data for the systems containing tetrahydropyran and furan is investigated. Finally, it is shown that the presence of THP or furan in the system has a negative effect on the kinetics of methane and carbon dioxide hydrate formation, and reduces the amount of gas uptake in the hydrate formation process.

Experimental measurement and thermodynamic modelling of hydrate phase equilibrium conditions for krypton + n-butyl ammonium bromide aqueous solution

In this study, experimental hydrate dissociation data for krypton in the presence of aqueous solutions of TBAB at varying concentrations of 0, 0.05, 0.10 and 0.20mass fraction TBAB were measured. The measurements were undertaken in the temperature range of (274.1 to 297.1) K and pressures ranging from (0.22 to 11.97) MPa. In addition, semi-clathrate hydrate dissociation data for the TBAB+water system at a pressure of 99.8kPa and at various TBAB concentrations of 0.05, 0.10, 0.20 and 0.30mass fractions were measured. The isochoric pressure-search method was used to undertake the measurements. The purpose of this study was to investigate the effect of TBAB aqueous solution on krypton hydrates. The results reveal that the TBAB aqueous solutions with concentrations of 0.05, 0.10 and 0.20mass fractions show a drastic promotion effect on the krypton hydrate causing a shift of the P-T equilibrium line to lower pressures and higher temperatures. In addition, increasing the TBAB concentration increases its promotion effect. The hydrate dissociation conditions for krypton+water+TBAB system were represented using a model based on the work of Chen and Guo, (Chem. Eng. J. 71 (1998) 145–151) and Joshi et al. (J. Nat. Gas Chem. 21 (2012) 459–465). The model results show a satisfactory agreement with the experimental data, with an absolute relative deviation (ARD%) below 0.3%.

Experimental Measurement and Thermodynamic Modeling of Hydrate Dissociation Conditions for the Argon + TBAB + Water System

Gas hydrate (clathrate hydrate) dissociation data at low to moderate pressures are necessary for practical applications, e.g., for gas separation. However, it is often known or recognized that the separation conditions encountered exist at high pressures and low temperatures. One solution to this problem is the application of the quaternary ammonium salts (QAS) semiclathrate hydrates such as tetra-n-butyl ammonium bromide (TBAB) which can moderate the hydrate dissociation conditions. The addition of TBAB to the solution enables a shift in the pressure-temperature diagrams to lower pressures and higher temperatures. In this study, the isochoric pressure search method1,4,13,28,34−37 was used to measure hydrate dissociation conditions for the argon + TBAB + water system. The measurement of hydrate dissociation conditions were performed at various TBAB concentrations, namely, (0, 0.05, 0.10, 0.20, and 0.30) mass fraction. The experiments were performed in the temperature range of (274 to 293.6) K and pressures ranging from (0.34 to 12.32) MPa. Results indicate that TBAB has a significant promotion effect on argon hydrate formation. In addition, increasing the TBAB concentration increases its promotion effect. A thermodynamic model was developed to predict the hydrate dissociation conditions for the system of argon + TBAB + water. The results show good agreement between the experimental measurements and model results.

Experimental Measurements and Thermodynamic Modeling of the Dissociation Conditions of Clathrate Hydrates for (Refrigerant + NaCl + Water) Systems

Experimental gas hydrate dissociation data for the refrigerants R134a, R410a, and R507 in the absence and presence of NaCl aqueous solutions at various molalities were measured. The binary systems, in this study, which consisted of {chloro(difluoro)methane (R22), 1,1,1,2-tetrafluoroethane (R134a), (0.5 mass fraction difluoromethane + 0.5 mass fraction 1,1,1,2,2-pentafluoroethane) (R410a), or (0.5 mass fraction 1,1,1-trifluoroethane + 0.5 mass fraction 1,1,1,2,2-pentafluoroethane) (R507)} + water were measured in the temperature range between (276.4 to 291.8) K and pressures ranging from (0.114 to 1.421) MPa. The ternary system R134a + water + NaCl, at three salt molalities of (0.900, 1.901, and 3.020) mol·kg–1, was measured in the temperature range between (268.1 to 280.6) K and pressures ranging from (0.086 to 0.383) MPa. For the ternary systems comprising of {R410a or R507} + water + NaCl, at two salt molalities of (0.900 and 1.901) mol·kg–1, measurements were undertaken in the temperature range between (273.9 to 290.9) K and pressures ranging from (0.226 to 1.345) MPa. The isochoric pressure-search method was used to undertake the measurements. The purpose of this study is to generate accurate hydrate phase equilibrium data which will be used to design wastewater treatment and desalination processes using gas hydrate technology. The results show that the presence of NaCl in the aqueous solutions has a thermodynamic inhibition effect on refrigerant gas hydrates. Modeling of the data measured was undertaken using a combination of the solid solution theory of van der Waals and Platteeuw for the hydrate phase, the Aasberg–Petersen et al. model for the electrolyte aqueous system, and the Peng–Robinson equation of state with classical mixing rules for the liquid and vapor phases. The correlated model results show good agreement with the experimental dissociation data.

Equilibrium Data of (tert-Butylamine + CO2) and (tert-Butylamine + N2) Clathrate Hydrates

In this work, experimental hydrate dissociation pressures of the (tert-butylamine + CO2) and (tert-butylamine + N2) systems were reported at (0.005, 0.015, 0.03, 0.056 and 0.093) mole fraction of tert-butylamine with measurements made in the temperature range of (273.5 to 283.3) K and in the pressure range of (2.27 to 13.79) MPa. The equilibrium data were generated using an isochoric pressure-search method. The hydrate dissociation data for the (CO2 + water) system were obtained in advance and compared with experimental data reported in the literature, and the acceptable agreements demonstrate the reliability of the experimental method and apparatus employed in this work. Dissociation experimental results indicated that tert-butylamine had an inhibition effect on the dissociation conditions of carbon dioxide, shifting the dissociation conditions of CO2 hydrate to lower temperatures/higher pressures, while for the (tert-butylamine + N2 + water) system, tert-butylamine showed a hydrate promotion effect, whi...

Dissociation Data and Thermodynamic Modeling of Clathrate Hydrates of Ethene, Ethyne, and Propene

Ethene, ethyne, and propene are common and important industrial gases which are known to form hydrates. There exists in the open literature some hydrate dissociation data for simple hydrates of the three hydrocarbons. Unfortunately the data reported in literature are in some instances very limited, and the data sets are not always in agreement with each other. To evaluate the hydrate data for these hydrocarbons, new hydrate dissociation data were measured and are compared to that in the literature. Measurements for ethyne were undertaken in the temperature and pressure ranges of (273.2 to 285.5) K and (0.614 to 2.467) MPa, respectively. The temperature and pressure ranges for the propene measurements were (273.5 to 274.4) K and (0.492 to 0.613) MPa, respectively. The solid solution theory of van der Waals and Platteeuw, together with the Valderama–Patel–Teja equation of state and the non-density-dependent mixing rules were used to model the experimental hydrate dissociation conditions. Model predictions w...

Phase Equilibria of Clathrate Hydrates in (Methane + Cyclooctane + Water), (Methane + 3,3-Dimethyl-1-butene + Water), (Methane + 2-Pentanone + Water), or (Methane + 3-Pentanone + Water) Systems

In this communication, experimental hydrate dissociation data for the (methane + cyclooctane + water), (methane + 3,3-dimethyl-1-butene + water), (methane + 2-pentanone + water) and (methane + 3-pentanone + water) systems are reported in the temperature range of (273 to 286) K. Experimental data were generated using an isochoric pressure search method. The experimental hydrate dissociation data for the (methane + 2-pentanone + water) and (methane + 3-pentanone + water) systems are compared to experimental dissociation data for methane hydrate, and it is found that 2-pentanone or 3-pentanone likely shows an inhibition effect on methane clathrate hydrates.