(438a) Development and Testing of Amine-Type Scavengers for the Removal of H2s from    Liquid Sour Crudes

Agbroko, O. - Presenter, Lamar University
Benson, T. J., Lamar University
Holmes, W. E., University of Louisiana
As the worldwide transportation sector grows due to global population expansion as well as growing economies, particularly in China and India, fossil fuel hydrocarbon based energy will continue to be the primary energy feedstock over the next few decades. Consequently, meeting the demand for fossil fuels has been met with many environmental and processing challenges, especially for crudes with higher H2S content. Crude oils that have sulfur concentrations more than 0.5 wt% are considered sour crudes, since they are characterized by a foul, odorous smell. Sour crudes are of lower quality and present serious health and environmental concerns. Therefore, sustainable measures to lower the sulfur content (i.e. crude oil sweetening) are of significant importance, financially and environmentally. Organic sulfur compounds, such as di-benzothiophene, are usually converted using hydro-desulfurization reactions and are not seen has problematic for transportation of crude oils from the wellhead to the refinery. Removing of H2S at the wellhead before transporting via pipeline or railcar increases the value of crude oil and in some cases is necessary to conform to legal transport laws. Hydrogen sulfide, however, is normally removed using amine based absorbing materials, known as scavengers.

Hydrocarbon companies are exploring the prospect of greener and more cost-efficient methods for the scavenging (i.e. chemical absorption) of H2S from crude oils. The most used non-regenerative absorbent for H2S scavenging is a class of compounds known as triazines. Triazines are typically formed from a condensation reaction between an amine and a carbonyl compound. In-line scavenging of H2S is the favored technique for producing subsea wells containing crude oils with minute H2S concentrations especially when the well is coupled to a host facility for which there is no H2S scavenging or where it is too costly to implement. This work explores the fundamental characteristics of seven common scavengers, namely through FTIR and Raman spectroscopies, to identify the molecular facets for top-performing scavengers. In particular, this work identifies which scavenger-type is best for a particular crude oil type (i.e. acidity, aqueous content, H2S content, etc.). Each of the scavengers were tested in H2S-contaminated crude oils at various conditions, including temperature and reactor stirring rates. These results will be shown along with a proper delivery system to add scavenger compounds during the filling of a rail tanker or even injection into a pipeline.