Copper sweetening is a petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

 refining

Refining

Refining is the process of purification of a substance or a form. The term is usually used of a natural resource that is almost in a usable form, but which is more useful in its pure form. For instance, most types of natural petroleum will burn straight from the ground, but it will burn poorly...

 process using a slurry

Slurry

A slurry is, in general, a thick suspension of solids in a liquid.-Examples of slurries:Examples of slurries include:* Lahars* A mixture of water and cement to form concrete* A mixture of water, gelling agent, and oxidizers used as an explosive...

 of clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

 and cupric chloride to oxidize mercaptans. The resulting disulfide

Disulfide

In chemistry, a disulfide usually refers to the structural unit composed of a linked pair of sulfur atoms. Disulfide usually refer to a chemical compound that contains a disulfide bond, such as diphenyl disulfide, C6H5S-SC6H5....

s are less odorous and usually very viscous, and are usually removed from the lower-boiling fractions

Fractional distillation

Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation...

 and left in the heavy fuel oil fraction. http://nobel.scas.bcit.ca/resource/glossary/a-c.htm#coppersweethttp://productsearch.machinedesign.com/definition/Chemical_Engineering/Linde_copper_sweetening

Copper sweetening introduces trace amount of copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 into the resulting products, which tends to have detrimental effecs as it leads to formation of gum

Gum

-Natural gums:* Natural gum, any of a number of naturally occurring resinous materials in vegetative species* Gum anima* Gum arabic, used as food additive, adhesive et al.* Cassia gum* Dammar gum* Gellan gum* Guar gum* Kauri gum* Locust bean gum* Spruce gum...

my residues. (Other sources of copper include contact with refinery parts made of copper and copper alloys.) Copper is one of the most active instability promoters, and concentrations as low as 0.1 ppm can have marked negative effect. To combat these, metal deactivator

Metal deactivator

Metal deactivators, or metal deactivating agents are fuel additives and oil additives used to stabilize fluids by deactivating metal ions, mostly introduced by the action of naturally occurring acids in the fuel and acids generated in lubricants by oxidative processes with the metallic parts of...

s are added to some fuels.