Experiment of Extraction and Purification Technology of Helium Dissolved In Geothermal Water In Weihe Basin

Helium is a rare inert gas, due to its special physical and chemical properties, it is widely used in defense and military industry, aerospace, nuclear industry, clinical medicine, deep-sea diving, cryogenic science and many other high-tech and cutting-edge scientific research fields. Important scarce resources for industrial development. At present, the helium consumed in the global market mainly comes from helium-containing natural gas. The helium-containing water-soluble gas (water-soluble helium) found in the geothermal water of the Weihe Basin has a different accumulation type from helium-rich natural gas and belongs to another new helium gas source,the helium content is between 0.12-3.5%, with a maximum of 9.5%. It has the characteristics of wide distribution, high grade, stable resources, and water, gas and heat associated with it. It was formed under the special geological conditions in the Wei River Basin, and its discovery and exploitation may change the situation that China’s resource-poor helium and helium-related products mainly depend on imports. In March 2016, Sinopec and the Chinese Academy of Sciences cooperated to complete the research and development of new technologies and equipment for the extraction of water-soluble helium in the basin at room temperature, and established the first "water-soluble helium extraction test station" in China. The coupled process of"membrane separation (MS)+pressure swing adsorption(PSA)"technology at room temperature has solved the problem of water-soluble helium extraction very well, the concentration of water-soluble helium is increased from about 2.5% to 50% by MS, and can be continuously purified to more than 99% by PSA, and the highest is 99.5%. The concentration of helium has reached the industrial helium level. Compared with the "cryogenic method" commonly used in helium-bearing natural gas fields at home and abroad, this method has the advantages of low investment cost, low energy consumption, low operating cost, simple process, convenient maintenance, energy saving and environmental protection. The Xianyang area is a favorable enrichment area for water-soluble helium. The establishment of a pilot development test area for water-soluble helium extraction with an annual production capacity of 10,000 cubic meters in the Xianyang area is an innovative new comprehensive development model of "geothermal + helium", which is a new model for water-soluble helium in the Weihe Basin. The development and utilization of natural gas resources plays a role in demonstration and promotion. It is recommended to pay attention to the comprehensive utilization of geothermal-related associated resources in the development of geothermal resources in other regions, so as to facilitate the high-quality development of geothermal resource development. At the same time, the helium "MS + PSA" coupling extraction technology can also be applied to the extraction of helium from gas fields with low helium content (0.05-0.1%) in China. Once the technology is successfully applied in gas fields, it will play an important role in accelerating the removal of the “helium-poor country” in my country.