Over 30% of the world's identified gas reserves contain carbon dioxide (CO2) and hydrogen sulfide (H2S). Recovering these acid gases is a major challenge for industry and represents a key research topic for our R&D teams. As a trailblazer in this particular field, TotalEnergies has transformed this constraint into a technological asset. A prime example is the Group's new HySWEETTM solvent, which is capable of eliminating acid gases and sulfur compounds at the same time when treating natural gas. This technology also lowers the amount of energy required by the gas treatment process and thereby helps reduce the carbon footprint.
The high additional costs with sulfur compounds
Acid gases are corrosive, toxic and even inflammable, meaning that the risks are severe. To address the hazards inherent in such gases, commercial specifications are becoming increasingly stringent as efforts are made to ensure that production activities for these resources are as environmentally friendly as possible. This applies to carbon dioxide and hydrogen sulfide, as well as their sulfur compounds, including mercaptans (RSH) and carbonyl sulfide (COS).
When it comes to such compounds, using amine-based solvents to extract the acid gases falls short of the mark. Additional treatment steps are required to specifically eliminate each sulfur impurity, with major repercussions on the final installation.
HySWEETTM: proven industry-level durability and efficiency
In response to these needs, our researchers developed the HySWEETTM technology on an industrial scale back in 2007. Drawing strength from our gas treatment expertise and skills, HySWEETTM features a hybrid solvent that combines the chemical capacities of an amine with the physical properties of a cosolvent to simultaneously absorb CO2, H2S and sulfur compounds, such as mercaptans and COS. A major upside with this technology is that it can be seamlessly integrated into existing facilities without requiring any modifications.
Switching over from the DEA-water solvent, which was previously used to sweeten this gas (containing 17% H2S and 10% CO2), to the HySWEETTM DEA solvent went smoothly without needing any changes to the equipment.
HySWEETTM: the first in an extended product line
In addition to providing an industrial-scale demonstration, our teams have pursued their R&D activities (research and development), which are focused on the physical and chemical aspects of the solvent and sulfur compounds, with the objective of enhancing the technology. As well as HySWEET® DEA, our range now includes:
- HySWEETTM MDEA, which completely extracts the H2S and its sulfur compounds, and achieves variable separation of the CO2.
- HySWEETTM MDEA-PZ, which completely extracts the H2S and ensures controlled extraction of the CO2. Not only is it more stable, but it is less energy-intensive and corrosive than DEA.
Since November 30, 2021, the HySWEETTM MDEA-PZ technology has been in the hands of Axens, which is responsible for marketing the product to meet market demand. The process of transferring knowledge and expertise is currently underway and will continue until the summer of 2023. Note that two projects (one in North America and the other in the Middle East) are already pending validation.