Sulfur Chemicals for Ethylene Production

Sulfur chemicals, primarily dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), have long been reliably and safely used as sulfiding agents to generate the needed H2S utilized in the production of ethylene. The addition of sulfur chemicals in the feedstock being cracked stabilizes the cracking furnace radiant coil inner diameter surfaces which reduces the formation of coke and CO that adversely impacts furnace operational run lengths and some acetylene removal operations. Sulfur chemicals allow operators to maximize furnace utilization rates and profitability for their overall production unit.

In North America, both DMS and DMDS are produced domestically as either by-products or as intermediates within other dependent chemical processes, or they are imported from Europe or Asia. In the last 5 years, plentiful advantaged feedstocks and increased global demand for polyethylene have driven significant investments that have expanded ethylene production in North America. At the same time, changes in unrelated markets and technology are impacting the traditional supply balance of the by-product or intermediate sulfur chemicals. In addition, challenges with global supply chains also continue to occur. This paper discusses the dynamics driving uncertainties in the supply of these critical sulfur chemicals as well as Chevron Phillips Chemical’s effort to evaluate the sulfur chemical dimethyl sulfide (DES) as a potential candidate.