LNG production in Russia in 2024 amounted to 34.7 million tons. By 2035, it is expected to triple. While pipeline gas remains significantly cheaper, well-known political issues in recent years have reduced deliveries through this distribution channel. Additionally, LNG trade reduces dependency on a single supplier, which is particularly important under current conditions.
The growing interest in LNG trade has also driven research activity in this field. An additional incentive for Russian scientists has been the European Union's embargo on the supply of various types of industrial equipment related to LNG. One of the most relevant research areas is the development of efficient methods for utilizing boil-off gas. Scientists from Empress Catherine II Saint Petersburg Mining University have proposed an efficient LNG storage system that utilizes a gas ejector for boil-off gas recovery.
The development has already won a gold medal at the Hi-Tech innovation exhibition in St. Petersburg. Equally important is the recognition from industry professionals. According to the author of the development, Yana Martynenko, an assistant at the Department of Oil and Gas Transportation and Storage, the technical proposals for the design of an ejector system for boil-off gas recovery from LNG storage tanks have been successfully implemented at Gazprom LNG Technologies.
LNG storage tanks are well insulated, yet completely preventing vaporization is impossible. Therefore, all LNG storage facilities, tankers, and gas carrier vehicles are equipped with vapor recovery systems. The simplest method is flaring, but its environmental drawbacks are evident. Today, small-scale LNG plants often use a technology that heats boil-off gas to meet standard gas network parameters. However, from an energy consumption perspective, this is inefficient— the facility has already invested in cooling and then spends additional resources on reheating.
Large-scale LNG plants typically remove vapor from storage tanks using booster compressors. These compressors increase the pressure of the recovered gas and either direct it for re-liquefaction or use it for the storage tank system’s needs.
«In comparison with a booster compressor, the ejector we propose consumes significantly less power. It does not require an electrical connection, and its energy consumption is only associated with supplying a high-pressure active gas flow, which extracts the boil-off gas from the LNG tank through the ejector based on Bernoulli’s equation. Essentially, it operates like a gas burner or a paint sprayer. While a compressor has a power consumption of 75 kilowatts, the ejector requires only 2.5 kilowatts in equivalent terms.
Capital and operational costs are also incomparable, particularly in terms of dimensions, metal consumption for manufacturing, repair, and maintenance costs. Additionally, a compressor poses a greater risk of injury, whereas the ejector has no rotating parts.
Currently, research on ejector-based boil-off gas recovery is being conducted both in Russia and abroad. However, as far as we know, such systems have not yet been put into mass production— primarily due to challenges in selecting optimal parameters» – said Yana Martynenko.
In 2024, under the supervision of Doctor of Technical Sciences, Professor Viktor Bolobov, she defended her PhD dissertation on the development, titled "Justification for the Application and Parameter Selection of a Gas Ejector in LNG Storage Systems." The research findings have already been secured with three patents.
The study scientifically proved that the volume of recovered boil-off gas does not depend on the pressure and, consequently, the consumption of the active gas flow as long as a critical pressure differential is maintained. Simply put, this discovery enables the minimization of energy consumption for supplying the active flow. Additionally, the novelty of the development lies in the creation of an algorithm for selecting the optimal ejector geometry. This was achieved after numerous experiments conducted on an experimental test bench assembled at the university.
«Further research is possible in the direction of developing an efficient two-phase ejector. This type of ejector would not only capture boil-off gas from the storage tank but also liquefy it. Similar experiments have already been conducted, but so far, researchers have only been able to achieve liquefaction of about 50% of the vapor entering the ejector. The major research challenge now is to maximize the transition of vapor into the liquid phase, thereby improving the energy efficiency of the ejector process» – shared Yana Martynenko regarding her future research plans.
She also informed Forpost about her upcoming participation in refining the ejector-based boil-off gas recovery system at actual industrial sites. As mentioned earlier, such collaboration has already been successfully implemented at Gazprom LNG Technologies. Interest in joint work has also been expressed by Cryogas JSC and Lennpromavtomatika Research and Production Corporation. Moreover, almost all LNG production enterprises are potential stakeholders, including Gazprom LNG Portovaya, Yamal LNG, and even international manufacturers.