Catalyst – solid sorbent – or support therefor: product or process – Regenerating or rehabilitating catalyst or sorbent – Gas or vapor treating
Reexamination Certificate
2001-09-07
2004-05-11
Silverman, Stanley S. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Regenerating or rehabilitating catalyst or sorbent
Gas or vapor treating
C502S035000, C502S036000, C502S053000, C502S325000, C502S330000
Reexamination Certificate
active
06734130
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a hydrocarbon hydrogenation catalyst composition, a process of treating a hydrogenation catalyst composition, and to a hydrogenation process employing such hydrogenation catalyst composition.
It is known to one skilled in the art that a less unsaturated hydrocarbon compound can be produced by a thermal cracking process. For example, a fluid stream containing a saturated hydrocarbon such as, for example, ethane, propane, butane, pentane, naphtha, and the like and combinations thereof can be fed into a thermal (or pyrolytic) cracking furnace. Within the furnace, the saturated hydrocarbon is converted to an unsaturated hydrocarbon compound such as, for example, ethylene or propylene. Such unsaturated hydrocarbons are an important class of chemicals that find a variety of industrial uses. For example, ethylene can be used as a monomer or comonomer for producing a polyolefin. Other uses of unsaturated hydrocarbons are well known to one skilled in the art.
However, unsaturated hydrocarbons produced by a thermal cracking process generally contain an appreciable amount of less desirable highly unsaturated hydrocarbon(s) such as alkyne(s) or diolefin(s). For example, ethylene produced by thermal cracking of ethane is generally contaminated with a highly unsaturated hydrocarbon, such as acetylene, which must be selectively hydrogenated to a less unsaturated hydrocarbon, such as ethylene, but not to a saturated hydrocarbon such as ethane, in a hydrogenation process.
In addition, catalyst compositions comprising palladium and an inorganic support, such as alumina, are known catalyst compositions for the hydrogenation of highly unsaturated hydrocarbons such as alkynes and/or diolefins. For example, U.S. Pat. No. 4,484,015 discloses the use of a palladium and silver catalyst composition supported on alumina for the selective hydrogenation of acetylene to ethylene. Also for example, U.S. Pat. No. 5,510,550 discloses the use of a palladium, silver, and alkali metal catalyst composition supported on alumina for an even more selective hydrogenation of acetylene to ethylene. The operating temperature for the hydrogenation process is selected such that essentially all highly unsaturated hydrocarbon such as alkyne (e.g., acetylene) is hydrogenated to its corresponding less unsaturated hydrocarbon such as alkene (e.g., ethylene) thereby removing the alkyne from the product stream while only an insignificant amount of alkene is hydrogenated to a saturated hydrocarbon such as alkane (e.g., ethane). Such selective hydrogenation process minimizes the loss of desired less unsaturated hydrocarbons.
Thus, the development of a catalyst composition, a process of treating such catalyst composition, and a process of using such catalyst composition for the hydrogenation of highly unsaturated hydrocarbons such as diolefins (alkadienes) or alkynes to less unsaturated hydrocarbons such as monoolefins (alkenes) where such catalyst composition has improved selectivity, increased activity, and/or longer operating life would be a significant contribution to the art and to the economy.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved process of treating a hydrogenation catalyst composition, such as a palladium-containing hydrogenation catalyst composition, and a catalyst composition prepared according to such treatment process.
Another object of the present invention is to utilize a catalyst composition treated by a process of the present invention to hydrogenate a highly unsaturated hydrocarbon, such as acetylene, in admixture with a less unsaturated hydrocarbon, such as ethylene, to produce a further amount of less unsaturated hydrocarbon, such as ethylene, without the concurrent consumption of a significant portion of such less unsaturated hydrocarbon.
According to an embodiment of the present invention, a catalyst composition is provided which can be used for selectively hydrogenating a highly unsaturated hydrocarbon such as, for example, an alkyne or a diolefin. Such catalyst composition can be prepared by a process which comprises treating a hydrogenation catalyst composition, such as a palladium-containing hydrogenation catalyst composition, by contacting such catalyst composition with a first treating agent to provide a treated catalyst composition followed by optionally contacting with a second treating agent. Generally, such first treating agent comprises carbon monoxide. Generally, such second treating agent comprises a hydrogen-containing fluid.
According to another embodiment of the present invention, a process which can be used for selectively hydrogenating a highly unsaturated hydrocarbon to a less unsaturated hydrocarbon is provided. The process comprises contacting a highly unsaturated hydrocarbon with hydrogen, in the presence of a catalyst composition which has been treated according to a process of the present invention, under a condition sufficient to effect a selective hydrogenation of the highly unsaturated hydrocarbon.
Other objects and advantages of the present invention will be apparent from the detailed description of the present invention and the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
As used in the present invention, the term “fluid” denotes gas, liquid, vapor, or combinations thereof. The term “palladium” refers to palladium metal. The term “silver” refers to silver metal. The term “substantial” or “substantially” generally means more than trivial. The term “saturated hydrocarbon” refers to any hydrocarbon which does not contain any carbon-to-carbon double bonds or carbon-to-carbon triple bonds. Examples of saturated hydrocarbons include, but are not limited to, ethane, propane, butanes, pentanes, hexanes, octanes, decanes, naphtha, and the like and combinations thereof.
The term “highly unsaturated hydrocarbon” refers to a hydrocarbon having a triple bond or two or more double bonds between carbon atoms in the molecule. Examples of highly unsaturated hydrocarbons include, but are not limited to, aromatic compounds such as benzene and naphthalene; alkynes such as acetylene, propyne (also referred to as methylacetylene), and butynes; diolefins such as propadiene, butadienes, pentadienes (including isoprene), hexadienes, octadienes, and decadienes; and the like and combinations thereof.
The term “less unsaturated hydrocarbon” refers to a hydrocarbon in which a triple bond in a highly unsaturated hydrocarbon is hydrogenated to a double bond or a hydrocarbon in which the number of double bonds is one less, or at least one less, than that in the highly unsaturated hydrocarbon. Examples of less unsaturated hydrocarbons include, but are not limited to, monoolefins such as ethylene, propylene, butenes, pentenes, hexenes, octenes, decenes, and the like and combinations thereof.
The term “hydrogenation process” refers to a process which converts a highly unsaturated hydrocarbon such as an alkyne or a diolefin to a less unsaturated hydrocarbon such as a monoolefin or a saturated hydrocarbon such as an alkane. The term “selective” refers to such hydrogenation process in which a highly unsaturated hydrocarbon such as an alkyne or a diolefin is converted to a less unsaturated hydrocarbon such as a monoolefin without further hydrogenating the less unsaturated hydrocarbon to a saturated hydrocarbon such as an alkane. Thus, for example, when a highly unsaturated hydrocarbon is converted to a less unsaturated hydrocarbon without further hydrogenating such less unsaturated hydrocarbon to a saturated hydrocarbon, the hydrogenation process is “more selective” than when such highly unsaturated hydrocarbon is hydrogenated to a less unsaturated hydrocarbon and then further hydrogenated to a saturated hydrocarbon.
The term “gas hourly space velocity” refers to the numerical ratio of the rate at which a treating agent, such as a first or second treating agent of the present invention, is charged to a treating zone of the present invention (or the numerical ratio of the rate at which a hydrocarbon-containing
Bergmeister Joseph J.
Cheung Tin-Tack Peter
Johnson Marvin M.
Carroll Rodney B.
Chvron Phillips Chemical Company LP
Conley Rose PC
Reed K. KaRan
Silverman Stanley S.
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