Study On The Influence Of Water-soluble Reagents On Methane Hydrate Formation

Natural gas hydrate is not only an important potential energy source,but also derived from a series of hydrate technology applications based on the basic characteristics of hydrates.Therefore,the optimization of hydrate's own characteristics and generation and decomposition process has become an important topic in human research today.When pipelines transport natural gas or submarine gas pipelines,due to appropriate temperature and pressure conditions,natural gas hydrates are often blocked,causing serious economic losses and production safety problems.It is necessary to suppress the formation of natural gas hydrates in pipelines,but when natural gas hydrates As a medium for transporting natural gas,it needs to accelerate the formation of natural gas hydrates.Therefore,whether it inhibits or promotes the formation of natural gas hydrates,it has important research value for the application of hydrate technology.In this paper,the promotion or inhibition of three water-soluble reagents on natural gas hydrates was studied,and the promotion or inhibition mechanism was further explored,which provided some experimental support and theoretical basis for the rational application of natural gas hydrate technology.Salt is one of the most widely used methane hydrate inhibitors in the industrial field.Firstly,the inhibition performance of NaCl on methane hydrate was studied under static conditions.The experimental temperature was 276.15 K and the initial pressure was 6Mpa.The methane hydrate is inhibited in a NaCl solution with a mass fraction of 5%,but under pure conditions,whether it is pure water or a 5% mass NaCl solution,methane hydrate is preferentially formed at the gas-liquid interface,preventing The hydrate formation reaction continued,resulting in a decrease in the integrity and reliability of the experimental results.In order to further verify theinhibition performance of NaCl on methane hydrate,agitating(300r/min)was added to continue the comparative experiment;tetrahydrofuran to methane hydration was examined.The effect of the formation of the product,the optimal concentration of tetrahydrofuran on methane hydrate was explored,and the effect of tetrahydrofuran concentration and the addition of stirring on methane hydrate was compared.Finally,the amphoteric surfactant LAD-40(lauroyl amphoteric II)was examined.The effect of disodium acetate on the formation of methane hydrate in different concentration ranges(10~500ppm).The experimental results show that NaCl has a significant inhibitory effect on the formation of methane hydrate,which makes the temperature and pressure conditions of methane hydrate formation more severe.With the increase of NaCl concentration(5%~10%),the inhibition performance is enhanced.The results show that tetrahydrofuran not only It can improve the thermodynamic conditions of methane hydrate formation,and can promote the nucleation of methane hydrate and shorten the nucleation induction period.Tetrahydrofuran has the best effect on the promotion of methane hydrate formation.When the concentration is low(1%,5%)),the promotion of methane hydrate formation is weak,when the concentration is increased to20%,30%,the promotion effect on methane hydrate formation is optimal,but when the concentration of tetrahydrofuran continues to increase to 45%,it is hydrated to methane.The effect of the formation of the substance is weakened.When the pressure is constant,compared with the core temperature of methane hydrate formation under pure water conditions,the concentration of(10~500ppm)LAD-40 is added,and the nucleation temperature of methane hydrate changes little.Improve the thermodynamic conditions of methane hydrate formation;LAD-40 increases the gas-liquid contact area,shortens the nucleation induction time,and makes the hydrate in the reactor body phase As the concentration of LAD-40 solution increases,the rate of methane hydrate formation increases linearly,and the gas consumption does not change much,but it is significantly higher than that under pure water.Therefore,LAD-40 is a good kinetic promoter,but Does not have thermodynamically promoted properties.