US 5,595,634 A · Process for selective hydrogenation of highly unsaturated compounds and isomerization of olefins in hydrocarbon streams

Abstract

A process for treating C.sub.3 to C.sub.12 petroleum fractions, such as a light cracked naphtha to be used as an etherification feed stock in which H.sub.2 S is removed by distillation of at least the C.sub.3 fraction and mercaptans and diolefins are removed simultaneously in a distillation column reactor using a dual catalyst bed. The mercaptans and H.sub.2 S are reacted with the diolefins in the presence of a reduced nickel catalyst to form sulfides which are higher boiling than the portion of the feed which is fractionated to an upper hydrogenation catalyst bed of palladium for hydrogenating diolefins and acetylenes. The higher boiling sulfides are removed as bottoms along with heavier materials. Any diolefins not converted to sulfides and acetylenes are selectively hydrogenated to mono-olefins in the presence of a palladium oxide catalyst in an upper bed, producing overheads, substantially free of sulfur compounds, diolefins and acetylenes.

Claims14

Dependent claims

A process for the removal of mercaptans and/or hydrogen sulfide from aliphatic hydrocarbon streams, containing 3 to 12 carbon atoms comprising distilling a hydrocarbon stream comprising C.sub.3 to C.sub.12 hydrocarbons including alkanes, mono-olefins, diolefins, acetylenes and sulfur compounds to remove a fraction comprising at least C.sub.3 's and a portion of the sulfur compounds and leaving a residual, concurrently

(a) feeding hydrogen and a portion of the residual to a distillation column reactor containing a first bed comprising a first hydrogenation catalyst selected from the group consisting of nickel, cobalt, iron and compounds thereof and prepared in the form of a distillation structure and a second bed positioned in said column above said first bed, said second bed comprising a second hydrogenation catalyst selected from the group consisting of platinum, palladium, rhodium and the compounds thereof and prepared as a distillation structure wherein any sulfur compounds in the residual react in said first bed with a portion of the diolefins to form sulfides in a first reaction mixture,
(b) fractionally distilling the first reaction mixture to remove the sulfides with a heavier fraction and passing a lighter fraction into the second bed,
(c) hydrogenating the diolefins and acetylenes in said lighter fraction in said second bed to form a second reaction mixture,
(d) fractionally distilling the second reaction mixture, and
(e) removing a fraction overhead, which is substantially free of sulfur compounds, acetylenes and diolefins.

2 more elements

A process for removing mercaptans and hydrogen sulfide from a hydrocarbon stream and for selectively hydrogenating the diolefins and acetylenes therein while isomerizing the mono-olefins to equilibrium, comprising the steps of:

(a) feeding a C.sub.3 and heavier hydrocarbon stream containing hydrogen sulfide, mercaptans, olefins, diolefins and acetylene to a distillation column where the C.sub.3 's and hydrogen sulfide are removed as overheads and the remainder of the stream is removed as bottoms;
(b) feeding said bottoms and hydrogen to a distillation column reactor and concurrently therein:
(1) separating the C.sub.5 and lighter hydrocarbons and mercaptans from the C.sub.6 and heavier hydrocarbons in a stripping section;
(2) distilling the C.sub.5 and lighter hydrocarbons along with the mercaptans upwards into a first distillation reaction zone containing a supported nickel sulfide catalyst in the form of a catalytic distillation structure whereby a portion of the mercaptans react with a portion of the diolefins to form higher boiling sulfides which are distilled downward into said stripping section;
(3) distilling the C.sub.5 and lighter hydrocarbons, less said reacted mercaptans and diolefins, upward into a second distillation reaction zone containing a supported palladium oxide catalyst in the form of a catalytic distillation structure whereby a portion of the remaining diolefins and acetylenes are selectively hydrogenated to mono-olefins and a portion of the mono-olefins are isomerized;
(c) removing said hydrogenated and isomerized C.sub.5 and lighter hydrocarbons along with unreacted hydrogen as overheads from said distillation column reactor;
and
(d) removing said C.sub.6 and heavier hydrocarbons and said sulfides from said distillation column reactor as bottoms.

5 more elements

Dependencies are inferred from the claim text.

Process for selective hydrogenation of highly unsaturated compounds and isomerization of olefins in hydrocarbon streams

Life of this patent

Process for selective hydrogenation of highly unsaturated compounds and isomerization of olefins in hydrocarbon streams

Life of this patent

Abstract

Claims14