KFU scientists publish further inquiries into solidified methane storage

Two papers saw light in Energy & Fuels and ACS Applied Energy Materials.

Chair of the Laboratory of Hydrate Technologies of Utilization and Storage of Greenhouse Gases Mikhail Varfolomeev shares the gist of the hydrate technology, "Gas molecules under high pressure and low temperature conditions are contained within the cavities of the frameworks formed by water molecules. In this case, a single hydrate volume can accommodate about 160 volumes of gas. Transforming gas into gas hydrates is a promising method of natural gas storage and transportation."

Junior Research Associate Yulia Chirkova adds, "The hydrate method is easily scalable, so it can be used to convert associated petroleum gas into gas hydrates and then transport it and use it as fuel. It's more eco-friendly than burning. In addition, many villages and towns in Russia are still not gasified, as due to geographical reasons it is not profitable to build a pipeline there. The hydrate method of gas transportation and storage can be the solution to this problem. It has proven feasible in Japan."

According to Varfolomeev, the main disadvantage of the hydrate technology is the low rate of hydrate formation. To solve this problem, promoting agents are used which can accelerate the process of hydrate formation. One of the priority tasks of the laboratory is the search for chemicals that accelerate the conversion of gases into condensed state and allow the transformation of the gas into hydrate form in large quantities. To date, young scientists have been able to develop several more efficient and environmentally friendly—compared to the now widespread sodium dodecylsulphate (SDS)—reagents to accelerate hydrate formation. Those promoters have undergone successful laboratory tests.

Lab Technician Shamil Gainullin explains, "The promoters we synthesize (amino acid derivatives) are not surfactants, unlike most currently used ones. The fact is that most surfactants are toxic and form a large amount of foam when dissociating hydrates, making their use difficult. Our compounds are devoid of these flaws. Moreover, they outperform surfactants in efficiency."

To accelerate the formation of gas hydrates, scientists proposed to use an effective class of carboxyl-sulfonated surfactants (CSS). "Optimal promoters among carboxyl-sulfonated surfactants, in our view, are reagents with butyl and dodecyl fragments in a molecule. High-pressure autoclave experiments have shown that hydrophilic-hydrophobic balance strongly influences their promotional activity. As the length of the alkyl chain increases, the efficiency increases until the sample dissolves well in water," says Lead Research Associate Roman Pavelyev.

Carboxyl-sulfonated surfactants are well studied—they are part of many shampoos and detergents, adds Junior Research Associate Abdolreza Farhadian. These substances are non-toxic, safe for humans and animals and rapidly degrade in the environment. Now young scientists are actively working on increasing the efficiency of promotion and reducing foaming when dissociating gas hydrates. A unique laboratory device for the synthesis and research of the artificial formation of hydrates, which KFU plans to establish this year in cooperation with industry, will play an important role in this process.

More information:
Novel Amino Acid Derivatives for Efficient Methane Solidification Storage via Clathrate Hydrates without Foam Formation
eng.kpfu.ru/novosti/nauka/kfu- … ied-methane-storage/

Solidified Methane Storage Using an Efficient Class of Anionic Surfactants under Dynamic and Static Conditions: An Experimental and Computational Investigation
pubs.acs.org/doi/10.1021/acsaem.2c03240

Provided by Kazan Federal University