How is sulfur recovered from natural gas and petroleum refining?

Sulfur is recovered from natural gas and petroleum refinery gases primarily by separating it as hydrogen sulfide and subsequently converting it into elemental sulfur.1

The recovery process generally involves two key stages:

• Removal: In the refining of natural gas, "sour gas" is purified through a process called sweetening, where sulfur compounds are removed using a liquid absorbent such as ethanolamine. Similarly, in petroleum refining, a process known as hydrodesulfurization is used to strip sulfur atoms from oil molecules by mixing sulfurous fractions with hydrogen and a catalyst, which yields hydrogen sulfide.23
• Conversion: Once separated as hydrogen sulfide, the gas is converted into elemental sulfur using the Claus process. This method involves the partial burning of hydrogen sulfide to produce sulfur dioxide, followed by a reaction between the two to yield elemental sulfur.41