Quantitative kinetic inhibitor comparisons and memory effect measurements from hydrate formation probability distributions

Abstract In contrast with conventional experiments for ranking the performance of kinetic hydrate inhibitors (KHIs), the high pressure automated lag time apparatus (HP-ALTA) is not limited by the stochasticity of hydrate formation because it can make large numbers of formation measurements rapidly. An improved procedure for analysing HP-ALTA data is presented here in which formation probability density histograms with uniform temperature bin widths are constructed. Operations such as numerical integration and subtraction can then be applied to entire formation distributions without the need to regress the data to model analytic functions. This approach enables apparatus effects on the measured formation distributions to be quantified and mitigated. Using analogue natural gas mixtures, a demonstration of the improved method is reported here for six KHIs that were also tested using a conventional rocking cell. The cumulative formation probability distribution functions determined by numerical integration of the histograms were used to quantitatively (1) assess the performance of the KHIs, (2) study the memory effect in pure water, and (3) assess its impact on the performance of each KHI. The rankings of the KHIs obtained from the various performance metrics accessible through the HP-ALTA data were generally consistent with the rocking cell rankings, with the average absolute deviation in net subcooling for the two apparatus being 2 to 3 K. In the quiescent HP-ALTA samples, the three worst performing KHIs still had expected subcoolings of about 14 K unless the memory effect was present, in which case the expected net subcoolings of the three worst performing KHIs ranged from 0–6 K. In contrast the memory effect reduced the expected subcoolings of the three best performing KHIs by only 1–2 K. Using the new method of analysis, hydrate formation distributions measured with the HP-ALTA can also be used to identify regions of good and poor performance for a given KHI, which might aid in the determination of improved inhibition strategies or assist the development of improved hydrate inhibitors.

[1]  A. Soper,et al.  Search for memory effects in methane hydrate: structure of water before hydrate formation and after hydrate decomposition. , 2005, The Journal of chemical physics.

[2]  E. Chen,et al.  Cationic kinetic hydrate inhibitors and the effect on performance of incorporating cationic monomers into N-vinyl lactam copolymers , 2013 .

[3]  P. Hartley,et al.  Synthesis of Effective Kinetic Inhibitors for Natural Gas Hydrates , 2012 .

[4]  Amadeu K. Sum,et al.  Effective kinetic inhibitors for natural gas hydrates , 1996 .

[5]  C. Dicharry,et al.  Laboratory Evaluation of Kinetic Hydrate Inhibitors: A Procedure for Enhancing the Repeatability of Test Results , 2009 .

[6]  P. Rodger.  Methane Hydrate: Melting and Memory , 2000 .

[7]  P. Hartley,et al.  Probability distributions of gas hydrate formation , 2013 .

[8]  Jinhai Yang,et al.  Characterization of inhibition mechanisms of kinetic hydrate inhibitors using ultrasonic test technique , 2011 .

[9]  M. Kelland,et al.  Investigation into the strength and source of the memory effect for cyclopentane hydrate , 2013 .

[10]  Praveen Linga,et al.  Experimental investigation of the effect of poly-N-vinyl pyrrolidone (PVP) on methane/propane clathrates using a new contact mode , 2013 .

[11]  P. Bishnoi,et al.  A kinetic study of methane hydrate formation , 1983 .

[12]  M. Kelland,et al.  First Investigation of the Kinetic Hydrate Inhibitor Performance of Polymers of Alkylated N-Vinyl Pyrrolidones , 2013 .

[13]  E. D. Sloan,et al.  Quantifying hydrate formation and kinetic inhibition , 1998 .

[14]  J. Ripmeester,et al.  Structures of hydrocarbon hydrates during formation with and without inhibitors. , 2012, The journal of physical chemistry. A.

[15]  F. Esmaeilzadeh,et al.  Experimental and Theoretical Investigation of Double Gas Hydrate Formation in the Presence or Absence of Kinetic Inhibitors in a Flow Mini‐Loop Apparatus , 2009 .

[16]  E. May,et al.  Characterization of the volume and shape of quasi-spherical resonators using coordinate measurement machines , 2010 .

[17]  T. M. Svartaas,et al.  Experiments Related to the Performance of Gas Hydrate Kinetic Inhibitors , 2000 .

[18]  C. Dicharry,et al.  Hydrate Precursor Test Method for the Laboratory Evaluation of Kinetic Hydrate Inhibitors , 2010 .

[19]  Feridun Esmaeilzadeh,et al.  Experimental and theoretical investigation of simple gas hydrate formation with or without presence of kinetic inhibitors in a flow mini-loop apparatus , 2009 .

[20]  M. Kelland,et al.  An investigation into the laboratory method for the evaluation of the performance of kinetic hydrate inhibitors using superheated gas hydrates , 2011 .

[21]  P. Wilson,et al.  Development of a high pressure automated lag time apparatus for experimental studies and statistical analyses of nucleation and growth of gas hydrates. , 2011, The Review of scientific instruments.

[22]  A. Haymet,et al.  Liquid-to-crystal nucleation: A new generation lag-time apparatus , 2002 .

[23]  M. Kelland,et al.  Exploring Kinetic Hydrate Inhibitor Test Methods and Conditions Using a Multicell Steel Rocker Rig , 2013 .

[24]  J. Ripmeester,et al.  Assessing the performance of commercial and biological gas hydrate inhibitors using nuclear magnetic resonance microscopy and a stirred autoclave , 2013 .

[25]  Peter Englezos,et al.  Enhanced rate of gas hydrate formation in a fixed bed column filled with sand compared to a stirred vessel , 2012 .

[26]  J. Ripmeester,et al.  Natural Gas Hydrate Formation and Decomposition in the Presence of Kinetic Inhibitors. 2. Stirred Reactor Experiments , 2011 .

[27]  P. Hartley,et al.  Statistical Analysis of Supercooling in Fuel Gas Hydrate Systems , 2012 .

[28]  Ponnivalavan Babu,et al.  Pre-combustion capture of carbon dioxide in a fixed bed reactor using the clathrate hydrate process , 2013 .

[29]  Malcolm A. Kelland,et al.  History of the Development of Low Dosage Hydrate Inhibitors , 2006 .

[30]  E. D. Sloan,et al.  Fundamental principles and applications of natural gas hydrates , 2003, Nature.

[31]  Molecular simulations as a tool for selection of kinetic hydrate inhibitors , 2005 .

[32]  E. D. Sloan,et al.  Determining gas hydrate kinetic inhibitor effectiveness using emulsions , 2009 .

[33]  J. Ripmeester,et al.  Natural Gas Hydrate Formation and Decomposition in the Presence of Kinetic Inhibitors. 1. High Pressure Calorimetry , 2011 .

[34]  N. Solms,et al.  Synergistic kinetic inhibition of natural gas hydrate formation , 2013 .

[35]  P. Servio,et al.  Morphology Study of Structure I Methane Hydrate Formation and Decomposition of Water Droplets in the Presence of Biological and Polymeric Kinetic Inhibitors , 2009 .

[36]  Abbas Firoozabadi,et al.  Nucleation of gas hydrates , 2002 .

[37]  P. C. Chua,et al.  Tetra(iso-hexyl)ammonium Bromide-The Most Powerful Quaternary Ammonium-Based Tetrahydrofuran Crystal Growth Inhibitor and Synergist with Polyvinylcaprolactam Kinetic Gas Hydrate Inhibitor , 2012 .

[38]  Ross Anderson,et al.  Do We Have New Solutions to the Old Problem of Gas Hydrates , 2012 .