Helium is a scarce strategic resource widely used in leak detection, semiconductors, scientific research, and other fields. Currently, helium production primarily comes from the recovery and extraction of associated helium in natural gas. However, the helium content in China's natural gas is generally low (<0.1%), making helium resources relatively scarce. Therefore, developing research directions such as helium recovery from BOG in liquefaction plants, helium associated with geothermal water-soluble gas, and helium extraction from coalbed methane has become a primary approach to obtaining domestic helium sources.
Helium formation results from prolonged crustal movements, and neon, as a member of the same group as helium, is also generated and enriched. Due to neon's low boiling point (27K), it tends to accumulate during helium recovery processes such as BOG helium extraction. Unlike reactive gases such as hydrogen, neon is inert and cannot be removed through reactions with other substances. Thus, in helium production, neon becomes a persistent challenge, significantly affecting the quality of helium products (GB 4844-2011 requires high-purity helium to have a neon content ≤4PPM).
Common methods for removing neon from helium streams include ultra-low-temperature freezing, distillation, and cryogenic adsorption. Among these, freezing and distillation methods require an ultra-low-temperature environment below neon's boiling point, while cryogenic adsorption necessitates an environment below 60K. Higher demands for low-temperature conditions lead to increased equipment manufacturing costs and neon removal expenses, hindering the advancement of neon removal and high-purity helium purification technologies and equipment.
Different from the aforementioned common methods of neon removal, Anhui Zhongke Wanneng Technology Co., Ltd. has developed the CZ-200-80.2B molecular sieve specifically for neon removal from helium, based on years of research and development. This molecular sieve exhibits high adsorption capacity for neon across medium to low pressures and from cryogenic to deep cryogenic temperature ranges, particularly suitable for conditions where the neon partial pressure is <50Pa. Building on this, the company has also developed China's first dedicated neon removal and purification system for helium extraction from BOG at liquid nitrogen temperatures.
(VNE-80/He) has achieved excellent test results in multiple units including Inner Mongolia Sentai Natural Gas Co., Ltd. The helium purity meets the national standard for high-purity helium and satisfies the requirements for 6N electronic grade (see Figure 2). Compared to the commonly used ultra-low temperature neon removal technology, the neon removal helium purification device developed by our company features low equipment investment and operational costs, significantly reducing users' initial and secondary usage expenses.
Figure 1. On-site photo of the neon removal purifier.
Figure 2. Adsorption curves of the neon removal purifier for various impurities
Meanwhile, the CZ-200-80.2B molecular sieve has demonstrated surprising adsorption capabilities for high-pressure neon gas in the general refrigeration temperature range. Tests have confirmed its ability to achieve one-step adsorption and removal of 3500 PPM neon impurities from helium gas streams, further proving the *** adsorption performance of this molecular sieve for neon. When combined with our company's high-low temperature cycle helium purification equipment, it can meet the demand for neon removal in the general refrigeration temperature range without liquid nitrogen. This is particularly suitable for factories, laboratories, and other scenarios without liquid nitrogen, significantly reducing operational costs.
Figure 3. GC results of high-pressure neon removal experiment
The successful development of this molecular sieve and neon-removal helium purification equipment is the culmination of the company's years of research and development efforts. It also represents a significant advancement in China's high-purity helium production, marking our company's growing maturity in the research, development, and application of helium-neon separation technology and equipment. This achievement has laid a solid foundation for our company's application of natural gas helium extraction technology and market development in areas such as helium-neon separation from air separation tail gas.
Please stay tuned for updates on the development progress of our company's high-purity neon purification equipment with helium removal.