Abstract
Sulfur contaminants in the form of hydrogen sulfide and mercaptans are undesirable for various reasons during sour crude production. For example, hydrogen sulfide and mercaptans can be hazardous to personnel. Their presence can create major corrosion issues pertaining to the assets. Furthermore, these components can be objectionable because of their chemical reaction with other hydrocarbons or fuel system components. In addition to the risk of direct harm to exposed personnel, products and equipment, environmental considerations such as odor and emission control must also be addressed. Increasing urbanization is moving more and more housing developments within the affected zone of many facilities. Depending on local and national regulations, penalties and fines can result from exceeding either hydrogen sulfide or mercaptan emissions standards.
There are several chemistries available for treating hydrocarbon feeds containing sulfur compounds and acidic components like hydrogen sulfide and mercaptans. The early processes included treatment of the hydrocarbon fractions with caustic, clays and hydro-treating as well as the UOP Merox™ process. One disadvantage of caustic treatment is that disposal of spent caustic is undesirable for environmental reasons. One of the most popular methods of treatment comprises scrubbing with mono or diethanolamine in a regenerative amine system. Amine systems, however, cannot sufficiently remove mercaptans. Although several chemistries are effective in scavenging hydrogen sulfide, there is a need for chemistries effective for scavenging mercaptans, especially in the presence of hydrogen sulfide.
The paper presents new chemistries that scavenge hydrogen sulfide and simultaneously scavange mercaptans extremely efficiently. A lab technique is also presented that was designed to mimic a field gas-tower application. A new analytical technique is described that simultaneously detects hydrogen sulfide and mercaptans. The gas concentrations are detected before and after scavenging. A systematic performance evaluation proves the efficacy of the scavengers in simultaneously scavenging hydrogen sulfide as well as mercaptans.
