Overview
Flex desulfurization is a low-intensity oil treatment process that utilizes oxidation to reduce sulfur and impurities. This method leverages the natural tendency of certain oil-based impurities to oxidize, offering an alternative to high-energy hydroprocessing.
Comparison of Desulfurization Methods
Traditional Hydroprocessing (HDP)
Hydroprocessing reduces sulfur by heating oil to very high temperatures and applying high-pressure hydrogen. This forces chemical reactions that break down sulfur compounds. However, heavier oil feeds require even higher temperatures, leading to increased utility demands and higher greenhouse gas (GHG) emissions.
In addition, hydroprocessing is sensitive to the composition of the oil feed. High levels of impurities, especially in heavy crude, tend to deactivate HDP catalysts, reducing process efficiency over time.
Oxidation-Based Desulfurization Process
By contrast, the oxidation-based process involves adding oxygen to the oil to remove sulfur and other contaminants through catalyzed reactions at room temperature. This method reduces both capital and operating costs while also lowering GHG emissions. It is less affected by the presence of heavy impurities, making it more consistent for treating heavier crude sources.
Challenges Associated with Hydroprocessing
Several drawbacks are associated with hydroprocessing, particularly when treating heavier or more variable oil streams:
Environmental Impact
The process requires high operating temperatures and pressures, resulting in elevated GHG emissions and increased utility consumption.
Capital Requirements
Upgrading or replacing aging hydroprocessing units involves significant financial investment, often without yielding measurable decarbonization improvements.
Scale Limitations
Hydrogen gas is cost-effective only at large production scales, making HDP less suitable for smaller or distributed fuel inventories.
Catalyst Deactivation
Heavy crudes contain impurities that rapidly deactivate HDP catalysts, making the method less viable for treating lower-quality or high-sulfur feedstocks.
Alternative Approach to Oil Treatment
Oxidation-based desulfurization offers a method to treat oil and fuels with reduced environmental intensity and a smaller equipment footprint. In particular, this approach is better suited for processing distributed inventories and high-impurity feedstocks, which pose challenges for conventional hydroprocessing technologies.