Converting Oil into Products

Converting Oil into Products

1. Modification

   • Refiners also use modification to achieve finished products with desired properties by the rearrangement or alteration of hydrocarbon molecules. Two important modification processes are catalytic reforming and isomerization.
   • Catalytic reforming. Catalytic reforming (also called cat reforming) modifies naphtha into high-octane blendstocks for gasoline
   • Isomerization. This is the process used to create isomers. An isomer is a molecule or compound that has the same number of atoms as another but has a different arrangement of those atoms, which produces different physical and chemical properties.

2. Conversion

   • Conversion is the broad term applied to processes that crack (break apart), combine, or modify nongasoline and non–middle-distillate hydrocarbons into motor gasoline and compounds called middle distillates

3. Separation/Distillation

   • In the separation state, the first issue of concern is the removal of salts and any remaining water from the crude oil stream.
     • The incoming crude is typically first routed to a vessel called a desalter, in which extra water is added and the crude/water solution is intensely mixed and heated to about 250°F.
   • After the removal of water and salt, the crude undergoes a process called distillation.

4. Combination

   • The opposite of cracking is combination—the joining together of smaller hydrocarbon molecules to produce larger, more valuable ones.
     • Polymerization. Polymerization puts together a series of molecules.
     • Alkylation. Like polymerization, alkylation is used to put together propylene and butylene (from a cracking unit), but it uses isobutane and acidic catalysts to produce the desired higher-octane gasoline blendstock.

5. Cracking

   • Cracking is the breaking of large hydrocarbon molecules into smaller ones. Thermal cracking uses heat to achieve this end, while catalytic cracking uses catalysts to do so.
   • Thermal cracking
     • Steam cracking. One type of thermal cracking, steam cracking makes use of high-temperature steam to do its work
     • Coking. converts the residuals from distillation into more-valuable gases, middle distillates, gasoline blendstock, and naphtha, plus a by-product called coke
     • Visbreaking. A second kind of thermal cracking, visbreaking is used to reduce the viscosity of heavy residual fuel oil.
     • Catalytic cracking uses heat and pressure, but it also employs a catalyst to either speed up the process or allow it to occur at a lower temperature..

6. BY HUMBERTO PONCE

7. Enhancement

   • In general terms, enhancement is the use of selected processes to remove unwanted elements or compounds from a hydrocarbon at some stage in the refinery
   • Hydroprocessing
     • Hydroprocessing uses hydrogen to remove sulfur, nitrogen, nickel, and vanadium from gasoline and middle distillates.
   • Amine treating
     • Also sometimes called amine washing, this process uses amine solvents to remove hydrogen sulfide, a highly toxic gas, from oil.
   • Solvent extraction
     • A third common enhancement process, solvent extraction is also known as solvent recovery. At various stages in the refinery system, operators introduce a solvent into a product stream to selectively remove some component.
   • Sweetening
     • Sweetening is the process used to neutralize the sulfur compound mercaptan in gasoline and other intermediate and finished products.