Starting January 2024, Brock University Chemistry Department Nuclear Magnetic Resonance laboratory has a helium recovery system capable of liquefying up to 20 L daily. 90 percent of the helium used to keep our NMR superconductive magnets cold is now recycled. This project was done in collaboration with Quantum Technologies a Canadian company located in Squamish, British Columbia.
Helium Recover room.
Why recover helium ?
Helium is the second-most abundant element in the universe. On earth though, it is only generated by radioactive alpha delay and trapped in certain oil and gas deposits in the earth’s crust from where it can be extracted and purified. Due to its very low molecular weight it escapes earth’s gravity and this makes it a non-renewable resource. The most familiar use of helium is as a safe, non-flammable gas to fill party and parade balloons. However, helium is a critical component in many fields, including scientific research, medical technology, high-tech manufacturing, space exploration, and defense. A few examples:
- Essential diagnostic medical equipment such as MRI’s or Helium-neon lasers used in eye surgery.
- Defense applications: rocket engine testing, scientific balloons, surveillance craft, air-to-air missile guidance systems
- Thermographic cameras and equipment used by search and rescue teams and medical personnel to detect and monitor certain physiological processes.
- Various industries use helium to detect gas leaks in their products. Helium is a safe tracer gas because it is inert. Manufacturers of aerosol products, tires, refrigerators, fire extinguishers, air conditioners and other devices use helium to test seals before their products come to market.
- Cutting edge space science and research requires helium. NASA uses helium to keep hot gases and ultra-cold liquid fuel separated during lift-off of rockets.
- Arc welding uses helium to create an inert gas shield. Similarly, divers and others working under pressure can use a mix of helium and oxygen to create a safe artificial breathing atmosphere.
- Helium is a protective gas in titanium and zirconium production and in growing silicon and germanium crystals.
- Since helium doesn’t become radioactive, it is used as a cooling medium for nuclear reactors.
- Cryogenics, superconductivity, laser pointers, supersonic wind tunnels, cardiopulmonary resuscitation pumps, monitoring blimps used by the Border Patrol, and liquid fuel rockets all require helium in either their manufacture or use.
Therefore, helium recovery is a critically important activity that all users that have demand for helium in the high technology areas should consider. This is not easily done and it is a highly sophisticated technological solution. It requires sophisticated filtration as contaminants are naturally trying to get into the purification system.
Particularly in the last 25 years, the price of helium has increased by 10 fold due to increased consumption and availability became a huge risk factor in maintaining a superconductive magnet safe at field. Recycling helium on site substantially reduces its consumption as well as the availability risk factor.
How the system works
Helium is used by all NMR magnets to keep the solenoid coil cold at 4.2K (-269C) so that it is superconducting. This helium boils off slowly during normal usage and at a very fast rate during helium refills, when liquid helium is transferred into the NMR magnet dewar. Normally, this helium evaporates into the atmosphere and from there dissipates into space. However, with the helium recovery system, it flows through copper pipes to a compressor which either directs it to a liquefier during standard boil-off or compresses it into medium pressure storage tanks during helium fills. The gas is then purified by passing it through a nitrogen-cooled purifier, and finally it is condensed to liquid helium via a cryo-compressor. The liquefier can liquefy up to 20 L per day and its production dewar can hold up to150L. From the production dewar the liquid helium is transferred directly into the NMR magnets via a long transfer line. This makes the transfer even more efficient since it eliminates the need for a transport dewar.
Construction
From the get-go this project took about one year to complete. Initial phase involved lab preparation that required high power electrical connections and chilled water being brought to the lab. Many thanks to John Clutterback, Cairns Research Building Supervisor for taking an active role and supporting this project. Design and completion of significant parts of the project such as header line, cryopurifier hoist, installation and connection of magnet dewars and the storage tanks were done by Brock University Machine Shop. Many thanks to Stephen Renda, Machine Shop Supervisor, this project would have not been possible without him. All magnets are located in the same room, a few meters away from the helium recovery system. Each magnet connects to the “recovery header” through a 3-way valve which allows us to disconnect the other magnets from the header when one magnet is filled to avoid pressure changes in the magnet dewars. This piping brings the helium from the magnets to the recovery compressor via a 20′ long flexible stainless-steel hose with 2″ diameter. The flexible line acts as a heat exchanger in order to warm up the helium gas from the magnet dewars up to room temperature in order to protect other parts of the system such as the helium compressor, from freezing. The header itself is fabricated from 2″ copper pipes. All the fittings and joints used on the header have been tested to hold 20 psi helium gas over a weekend. The comissioning and training was completed by a Quantum Technology project engineer and took one week.
System Status
Installed: January 2024
UPS for liquefier controller and recovery pump installed: March 2024
UPS Network controller for power outage messaging installed: April 2024
Cryogenic helium purifier nitrogen level sensor installed: May 2024
Liquid helium yearly consumption updated June, 2024
Without recovery system 650L & With recovery system 0L => Implied efficiency 100%
