The DSU® process is a disruptive approach for removing sulphur and metals from heavy oil. At the same time, it is simple, scalable and has very little direct SOx or GHG emissions. It does not leave big piles of coke or asphaltenes behind. The key to the process is sodium, a powerful reducing agent with a strong affinity for sulphur and metals atoms interspersed in the complex heavy oil molecules.
Here’s how it works:
Sodium, hydrogen and heavy oil are mixed in a reactor. The sodium preferentially seeks out and eliminates sulphur and metal atoms from the heavy oil molecules. Hydrogen capping of the open molecular bonds created during the removal of sulphur and metals results in lower-weight molecules that make the product oil ‘lighter’ without removing coke or asphaltenes. The resulting DSU® product contains very low levels of sulphur and metals and is also much lighter and less viscous than the original feed while retaining the energy content.
2. Oil-Solids Separator
The oil leaving the reactor contains solids, which are primarily sodium sulphide and metals. These solids are separated from the oil using gravity separation. The solid sodium sulphide is then dissolved in a solvent which is fed to the sodium recovery section. The metals do not dissolve and are recovered as a saleable by-product.
3. Sodium Recovery
The dissolved sodium sulphide is introduced to a bank of electrolytic cells. When electricity is applied across the cells, pure sodium is separated from the sodium sulphide and recycled back to the reactor. The sulphur is then a saleable by-product of the process.
DSU® technology has been proven on over 40 different global feedstocks from Alberta Bitumen, a variety of vacuum residues, and Jordanian oil shale.
1. Low Sulphur Bunker Fuel
Much of the world’s sea-borne shipping is fuelled by heavy fuel oil which is inexpensive but has high sulphur content. The sulphur emission regulations are being tightened worldwide. DSU® can surgically remove the sulphur along with harmful metals making a low sulphur bunker fuel. We have successfully demonstrated that we can produce ship-ready IMO and ECA-Compliant marine bunker fuels directly from vacuum residue and other heavy feedstocks
2. Heavy Oil
There is over five trillion barrels of heavy oil in 50 basins around the world; all of them contain heavy metals and sulphur that can be removed by DSU®. Currently, over one million barrels per day of raw Alberta oil sands bitumen is exported to the US for upgrading. At the same time, the trend in oil sands production is away from big mining projects and towards smaller-scale steam injection projects. This favours the modular nature of the DSU® process.
DSU® can be used for processing intermediate refinery streams such as vacuum residue and asphaltenes which contain sulphur and heavy metals. DSU® could debottleneck existing sulphur plants or a residue destruction process (e.g., delayed coking unit) or extend catalyst life, resulting in a higher value product.
4. Oil Shale Producers
Oil Shale (Kerogen) is the one of the most prolific forms of hydrocarbon on earth. A public forecast by PWC estimates global shale oil production to rise to 14 million barrels per day by 2035. The DSU® process has been tested on shale oils and it works well for removing heavy metals and sulphur.