Downstream (petroleum industry)
The downstream oil sector is a term commonly used to refer to the refining of crude oil, and the selling and distribution of natural gas and products derived from crude oil. Such products include liquified petroleum gas (LPG), gasoline or petrol, jet fuel, diesel oil, other fuel oils, asphalt and petroleum coke.
The downstream sector includes oil refineries, petrochemical plants, petroleum product distribution, retail outlets and natural gas distribution companies. The downstream industry touches consumers through thousands of products such as petrol, diesel, jet fuel, heating oil, asphalt, lubricants, synthetic rubber, plastics, fertilizers, antifreeze, pesticides, pharmaceuticals, natural gas and propane.
Crude oil is a mixture of many varieties of hydrocarbons, and may contain sulfurous compounds. The refining process converts most of that sulfur into hydrogen sulfide.
Raw natural gas also may contain gaseous hydrogen sulphide and sulfur-containing mercaptans, which are removed in natural gas processing plants before the gas is distributed to consumers.
The hydrogen sulfide removed in the refining and processing of crude oil and natural gas is subsequently converted into byproduct elemental sulfur. In fact, the vast majority of the 64,000,000 metric tons of sulfur produced worldwide in 2005 was byproduct sulphur from refineries and natural gas processing plants.