Sulfur Removal and Recovery

Abstract

Petroleum, natural gas and other fossil fuels contain significant amounts of sulfur. When burned, the sulfur becomes sulfur oxides (SO _x ), which can cause significant damage to the environment and human health. To minimize such damage and to ensure that finished products meet performance specifications, the sulfur is removed and transformed into useful chemicals, primarily sulfuric acid and fertilizers.

About 57% of the world's sulfur is a byproduct of oil and gas processing. The sulfur in natural gas is primarily H₂S, sometimes accompanied by mercaptans. The sulfur compounds in heavier fossil fuels include entrained H₂S, inorganic sulfur compounds and organic sulfur compounds. For natural gas and petroleum, the predominant sulfur recovery strategy is:

• 1. To convert all sulfur compounds into H₂S

• 2. To adsorb the H₂S into a solution containing an alkanolamine

• 3. To transport the H₂S-laden amine to a sulfur plant

• 4. To convert the H₂S into elemental sulfur with the modified Claus process

• 5. To employ Claus tail-gas treatment to increase overall recovery to > 99.5%.

Sulfur removal and recovery protects the planet from pollution by sulfur oxides and acids, which continue to threaten our atmosphere, water, land, and inhabitants. The challenge is worldwide, and so must be the solution.