Novel process recovers high-value products from natural gas

LINDE has developed a novel process to recover high-value products, including helium, from natural gas that successfully combines leading BASF and Linde technologies.

BASF and Linde announced earlier this year that they were to collaborate to serve natural gas processing applications. The companies said the ability to treat gas high in CO₂ and heavy hydrocarbons could allow them to serve a part of the industry currently relying on high-cost alternatives.

The novel process developed combines the recovery of helium, liquid hydrocarbons, and purified CO₂ with the adjustment of water and heavy hydrocarbon to dew point, as well as CO₂ concentration, in preparation for pipeline transport.

The process consists of an upstream BASF Durasorb hydrocarbon removal unit (HRU), two stages of Linde’s HISELECT gas separation technology powered by Evonik membranes, an integrated BASF OASE acid gas removal unit (AGRU), and an integrated Linde pressure-swing adsorption (PSA) unit.

BASF’s Durasorb HRU removes heavy hydrocarbons and water to meet pipeline dew point, producing liquid hydrocarbons as a valuable byproduct. Removing water and heavy hydrocarbons to below specified concentrations helps to prevent pipeline issues caused by condensation of liquids, and formation of solids, such as hydrates. Additionally, removal ensures high membrane performance.

The HISELECT stages simultaneously achieve helium enrichment and adjustment of CO₂ to meet pipeline specifications. Linde’s PSA technology is able to achieve helium enrichment up to 99.999%. The technology achieves the highest recovery rates in terms of helium product obtained from the feedgas to the PSA. Additionally, offgas from the PSA which contains some helium is recycled to the AGRU with virtually no helium losses in the PSA unit.

Helium is typically recovered from natural gas using a cryogenic process, which is costly and requires intensive energy. The developed process eliminates the need for cryogenic conditions, providing a new highly profitable source of helium.

BASF’s OSAE AGRU selectively removes CO₂ from an internal recycle, without loss of helium or methane.

The combinations of these technologies and the companies’ expertise allows for performance optimisation and the generation of additional value streams from gas processing. A project using this process is expected to generate additional revenue.

Detlef Ruff, Senior VP of Process Catalysts at BASF, said: “The newly developed process changes project economics […] as an additional high value stream can be generated, we’ll see more projects move forward.”

Helium has applications in medicine, science, industry, and recreation. David Cole-Hamilton, Chemistry Professor at the University of Edinburgh, says that though in some applications helium can be recycled – such as in the cooling of superconducting magnets in MRI scanners and deep-sea diving breathing mixtures – Earth’s natural abundance is decreasing.  Luke Manickam, Founder and Director of LM Intelligas, says there is an estimated 638bn ft³ of recoverable helium available on Earth, mainly from natural gas fields.