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Helium Production

Helium is relatively scarce on Earth, even though it is the second-most common element in the universe. It is a non-toxic, colorless, odorless, tasteless, inert, monoatomic gas. It is the first noble gas in the periodic table of elements, and its boiling point is the lowest among all of the elements. These properties make helium absolutely unique – there is no substitute, and no natural or manufactured replacement for it.

Helium leaves the atmosphere once it is used, making it impossible to recover from a landfill in the future, as can be done with other vital materials. While there is a large amount of helium in the atmosphere, it is prohibitively expensive to extract it from this source because its concentration is so low. It is estimated that distilling helium from the atmosphere would cost over US$1,500 per Mcf of helium, so all commercial helium supply on earth comes from underground reservoirs, in which helium produced by the radioactive decay of uranium and thorium is concentrated and trapped over hundreds of millions of years.

Helium has historically been produced as a by-product of certain conventional natural gas projects (less than 3% of natural gas deposits have more than trace amounts of helium), and those sources account for the bulk of helium supply today. The process of drilling for helium is identical to drilling for natural gas, allowing for the use of the same rigs, tools and personnel in these operations. However, exploration for helium is technically challenging and requires significant technical knowledge related to helium generation (from the underground decay or uranium and thorium), concentration and migration through formation fluids, exsolution and migration to traps in a gas phase, and reservoir evolution through time. Specialized expertise and methods across multiple disciplines are required to effectively search for new helium fields.

Once a commercially viable helium reserve has been discovered and development wells have been drilled, there are two stages in the production of helium, which can be combined into a single plant for larger deposits of helium.

Helium Separation/Purification

Because even 0.35% helium in a bulk-gas is considered a high-concentration, the first step is to separate the helium from the other components of the bulk gas stream. This can be accomplished through three principal technologies, which are often combined depending on the composition of the gas stream:

Membrane Separation

The helium content of a gas can be upgraded or purified by using high-pressure membranes which either concentrate or purify helium through selective diffusion of relatively smaller gas molecules through microscopic pores in the medium. This technology is relatively new for helium separation applications and may not be suitable for longer-lifetime projects.

PSA or TSA

Pressure-Swing Adsorption (PSA) or Temperature-Swing Adsorption (TSA). These technologies use temperature or pressure to cause selective adsorption of different sized gas molecules into a medium with a large surface area consisting of uniformly sized pore spaces. These technologies are time-tested, reliable, and can be deployed at small scale. The downside is that this process is less efficient than cryogenic separation, in terms of both energy use and product losses during the process.

Cryogenic Separation

Similar to the air separation units (ASUs) that are deployed worldwide in the industrial gas business, this technology uses low temperatures to cause different gases to condense off as a liquid in a fractionation tower. This process is ideally suited to helium, which has the lowest condensation point of any gas, but requires large scale for efficiency and has a higher initial capital cost.

Helium Liquefication

In order to economically ship helium around the globe, like LNG, purified helium gas must be liquefied prior to shipping so that it will fill a smaller volume. Liquid helium product also addresses a wider market, including those end-users who require the low temperatures of liquid helium. In the larger global helium plants, the gas is liquefied and stored into specialized 40-foot long ISO intermodal shipping containers. Due to the high-value of helium, it can also be economically shipped regionally as a gas in high-pressure tube trailers, although shipping costs for helium gas are higher than for liquid helium.