Technology Development and Commercialisation of a Novel Sweetening catalyst –‘Thoxcat ES™’ for LPG and Lighter Petroleum Fractions

Abstract

The presence of mercaptans in petroleum products like liquefied petroleum gas (LPG), naphtha, gasoline, aviation turbine fuel (ATF), and kerosene is undesirable due to their foul odour and highly corrosive nature. In commercial practice, the lower molecular weight mercaptans present in LPG and light straight run naphtha (LSRN) are extracted with alkali and catalytically oxidised to disulfides with air. This process is termed extractive sweetening. The mercaptans in slightly heavier straight-run naphtha or light thermally cracked naphtha are converted to disulfides by a liquid-liquid sweetening process where both extraction and oxidation occur in the same vessel. In the absence of a sweetening catalyst, excess use of alkali solution makes the two approaches expensive and time-consuming.