Helium is a scarce resource and to meet the global demand for helium, the construction of an LNG-BOG helium recovery plant not only produces helium, but also improves the efficiency of the LNG plant and brings considerable economic benefits. Fullcryo offers helium recovery systems and equipment that provide a reliable solution.
Boil-off gas (BOG) is the gas formed when part of the liquefied natural gas evaporates during the loading, storage, transportation and unloading of LNG. LNG is a cryogenic liquid (temperature below its boiling point) that is stored in insulated tanks (either storage tanks or cargo tanks) and evaporates when the temperature is above its boiling point.
Despite the insulation design of the tanks, heat still penetrates into the tanks during the transportation of LNG from the liquefaction plant to the receiving terminal, resulting in boil-off gas.
Boil-off gas increases the temperature in the tank and may cause the natural gas to return to its gaseous state. The increase in temperature causes the gas to expand in volume, which in turn increases the pressure in the tank. In order to maintain a stable tank pressure, the boil-off gas must be discharged from the tank.
The production of boil-off gas depends on the design and operating conditions of the liquefaction plant storage tanks and the transport ship cargo tanks. Taking a Chinese LNG plant with a daily processing capacity of 3 million cubic meters as an example, the evaporation gas flow rate it produces can reach 4,900 standard cubic meters per hour.
The main components of the evaporation gas produced by the LNG storage tank include methane, nitrogen, hydrogen, helium and a small amount of heavy hydrocarbons. By testing the composition of the non-condensable gas produced during the natural gas liquefaction process and the evaporation gas produced by the evaporation of LNG (collectively referred to as BOG for simplicity), it was found that the helium content was as high as about 3%. Based on this data, helium extraction has good economic benefits.
Therefore, in the existing natural gas liquefaction industry, extracting helium from BOG as a raw material and developing a process technology for the co-production of high-purity helium (gas helium or liquid helium with a purity of up to 99.999%) in LNG plants are of great significance to improving the economy of LNG plants and ammonia production units.
Helium is critical in electronics, medical (e.g. MRI equipment), aerospace and energy. However, helium is a scarce resource with limited global reserves, and demand continues to be intense.
Helium resources are expensive. Co-producing helium in the LNG production process can improve plant profitability, reduce waste and lower operating costs.
Recovering helium from LNG evaporated gas can support energy security and reduce reliance on traditional helium extraction methods.
Reading more：Sustainable Helium Extraction from LNG BOG
The evaporated gas, which is rich in methane and also contains helium, is collected from the LNG storage tanks. The evaporated gas is then cooled in a cold box through a series of heat exchangers.
Cryogenic Distillation (main method)
Purification and Liquefaction
The following figure is a schematic diagram of Fullcryo’s LNG-BOG recovery and liquefaction process.
The helium recovery process can be operated in parallel with LNG production, with no impact on LNG production. Fullcryo is available for LNG plants with capacities of 500,000 m3 and above. It can reduce the operating costs of LNG plants and there are short payback period and high profitability.
The following figure is a simulation design diagram of Fullcryo’s LNG-BOG recovery liquefaction system
Fullcryo’s LNG-BOG Cryogenic Helium Extraction System uses cryogenic separation to purify and liquefy helium. In cooperation with the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences, the system utilizes the results of large-scale cryogenic helium refrigeration technology to successfully industrialize domestic helium refrigeration equipment, forming a cryogenic industrial chain layout with LNG-BOG helium extraction, recovery, purification and liquefaction at its core. The purity of helium produced by the company can reach over 5N, with an annual output of about 280,000 cubic meters.
At present, Fullcryo has supplied nearly 10 sets of BOG helium extraction equipment and successfully operated them, contributing to the independent control of the country’s strategic helium resources.
During the project cooperation, Fullcryo gives full play to its own advantages and leads the whole process of construction and management, including design, procurement, construction and commissioning, providing one-stop service to ensure the project’s efficient progress and smooth delivery.
The picture below shows the site of our LNG-BOG helium extraction plant-based project, including related helium recovery equipment.
Regions with abundant natural gas resources and large LNG infrastructure are ideal for evaporative helium recovery, including:
USA (Texas, Wyoming): Established LNG hubs with an existing helium production base.
Middle East (Qatar, Saudi Arabia): Large-scale LNG export facilities.
Russia (Siberia): abundant natural gas reserves and stable helium levels.
Recovering helium from LNG vaporization gas and converting the by-product into a high-value resource will not only improve the economics of LNG plants, but also alleviate the global helium shortage. With advanced cryogenic technology and proven scalability, evaporative gas helium recovery technology promises to be a key innovation for the LNG and rare gas industries. For LNG operators, exploring evaporative gas helium recovery technology could open up new revenue streams, and providers such as Fullcryo can be contacted for customized solutions.
