Helium is a scarce strategic resource, especially in China, where helium resources are extremely scarce and almost entirely dependent on imports. However, helium has a wide range of applications and is a critical resource in high-end manufacturing fields such as military reconnaissance airships, industrial optical fibers, semiconductors, air conditioning, and welding. The 2017 Qatar diplomatic crisis once again severely disrupted the global helium supply, causing significant headaches for many gas companies and users. In China, helium consumption in the industrial sector has been growing rapidly year by year, yet there is no purification or recycling process in place. Instead, helium is used consumptively and directly released into the atmosphere, resulting in tremendous waste. Therefore, research into helium purification and recycling technologies in the industrial sector has once again become a focal issue in the industry.
[Technical Overview]
The common method for helium purification and recycling equipment is cryogenic condensation. Additionally, during the development of the equipment, numerous new technologies in the cryogenic field were employed, including vibration reduction for high-pressure helium compressors, specialized welding techniques for cryogenic-resistant high-pressure copper pipelines, and cryogenic high-pressure joint sealing technologies, to optimize the product. Building on this foundation, breakthroughs were achieved in membrane separation purification technology. Using a composite purification and separation method, low-purity helium with a concentration ≥10% can be purified to over 99.5%, with a system purification recovery rate ≥60%. It is reported that a high-purity helium recovery and purification project for optical fibers by a Chinese company successfully passed acceptance in Shenzhen and was connected to the user’s production line for formal gas supply. This project achieved disturbance-free gas recovery in high-temperature, high-speed, and high-dust environments, purifying raw gas with ≤50% helium content online and supplying it back as >99.999% high-purity helium. It features 24-hour unattended automatic operation, remote monitoring, and other functions. The project’s infrastructure, gas extraction and supply pipeline layout, and on-site construction were rigorously standardized, meeting user quality requirements. Overall, it reduces helium usage by over 55%, earning user recognition and praise.
【Technical Features】
The new industrial waste helium purification and recycling equipment manufactured by Chinese enterprises employs industrialized PLCs to monitor the purity, measurement, pressure, and temperature of helium within the system. This enables fully automated monitoring of compressors, drying and purification units, purifiers, and various control valves, achieving automated operation of the equipment. Fully intelligent, safe, and reliable automatic control technology is also a key feature and innovation of the project.
Helium purification is an internationally cutting-edge research field, utilizing methods such as cryogenic condensation, membrane separation, pressure swing adsorption, and chemical adsorption. Chinese enterprises have overcome the technical bottlenecks of cryogenic condensation separation methods based on low-temperature research, developing industrial helium membrane separation purification technologies and equipment to compete with global giants in helium purification. They are actively researching hybrid helium separation methods combining membrane separation with cryogenic separation, leveraging the high recovery rate and high purity advantages of both techniques. Helium is first coarsely purified via membrane separation and then finely purified using cryogenic separation, meeting industrial needs for both energy efficiency and high purity.
【Application Scope】
Helium is primarily used in medical, military, refrigeration, semiconductor, pipeline leak detection, high-precision welding, metal manufacturing, deep-sea diving, optoelectronic product production, balloon lifting, scientific research, and military fields. Below is an analysis of helium resource users based on its major applications.
(1) Nuclear Magnetic Resonance (Low-Temperature Superconducting) Field
Magnetic Resonance Imaging (MRI) systems utilize cryogenic superconducting magnet technology that requires liquid helium for cooling. Statistics show that MRI systems account for 34% of global helium consumption, making them a major end-use sector. Although demand for MRI systems is declining in developed countries, emerging markets continue to exhibit strong growth, sustaining robust demand for liquid helium.
(2) Refrigeration (Household Appliances) Field
Helium is primarily used for leak detection in condensers, evaporators, and piping systems.
(3) Semiconductor and Optical Fiber Field
Helium is mainly used as a protective gas for growing germanium and silicon crystals in the semiconductor industry, as well as a cooling and protective atmosphere gas in optical fiber preform production and fiber drawing processes.
(4) Welding Protective Gas
Purpose: To prevent certain metals from reacting with oxygen and nitrogen in the atmosphere when heated or melted, an inert atmosphere must be used for protection. A significant amount of helium is consumed in metal welding processes. In tungsten inert gas (TIG) welding, the non-consumable tungsten electrode, the heated metal filler, and the welding zone are shielded by a continuous flow of helium or a helium-argon mixture. The shielding gas mixture can be prepared by blending helium and argon in varying proportions. Depending on factors such as the welding technique, filler wire, and base metal being welded, the composition of the gas mixture may vary. Typically, the helium content in a helium-argon mixture ranges from 15% to 70%.
(5) Cryogenic Engineering Field
Applications: Due to helium's chemical inertness, extremely low liquefaction point, near-ideal gas behavior at all temperatures except extremely low ones, high heat capacity per unit mass, low viscosity, and high thermal conductivity, it is commonly used as the working medium in closed-cycle cryogenic refrigerators, as a cooling medium for low-temperature superconducting magnets and superconducting cavities in major scientific projects, as well as in scientific research experiments at universities and institutions.
(6) Aerospace Field
Applications: In rocket and spacecraft fuel systems, helium is used to purge cryogenic fuel and oxidizer storage tanks, as well as to pressurize the ullage space above cryogenic liquids, providing the pressure for direct transfer of liquid hydrogen and liquid oxygen or simply supplying net positive suction pressure for transfer pumps. Helium is often employed as the working medium in pneumatic control systems. Prior to rocket launches, cryogenic helium is used to pre-cool upper-stage liquid hydrogen rocket engines to achieve propulsion efficiency during the minutes of ignition. Liquid helium is also widely used in cryogenic radiation detectors and other specialized instruments for space exploration programs.