Chemistry of hydrocarbon compounds – Adding hydrogen to unsaturated bond of hydrocarbon – i.e.,... – Hydrocarbon is contaminant in desired hydrocarbon
Reexamination Certificate
1999-06-24
2001-10-02
Yildirim, Bekir L. (Department: 1764)
Chemistry of hydrocarbon compounds
Adding hydrogen to unsaturated bond of hydrocarbon, i.e.,...
Hydrocarbon is contaminant in desired hydrocarbon
C585S262000, C585S275000, C203S029000, C203SDIG006
Reexamination Certificate
active
06297415
ABSTRACT:
The present invention relates to a process for catalytic hydrogenation in which a heterogeneously catalyzed hydrogenation is combined with a distillation or rectification over a catalyst packing. The invention further relates to the use of a catalyst packing in processes for catalytic distillation.
The catalytic reaction of materials with simultaneous distillative separation of the reaction products is widely employed in the refinery sector, with cracker streams being selectively hydrogenated and separated.
EP-A1-0 556 025 relates to the selective hydrogenation of C
5
streams. The selective hydrogenation of a C
5
stream for preparing tert-amyl methyl ether (TAM) is described. Little to no saturation of the monoolefins occurs during the hydrogenation. Part of the monoolefins in the stream is isomerized. Diolefins are hydrogenated to monoolefins by passing a stream of light naphtha and hydrogen over a distillation structure which contains a catalyst comprising palladium oxide on aluminum oxide. Here, the catalyst is present in a plurality of pockets made of woven fabric which is held in a helical arrangement by means of a framework of open-meshed steel wire braid. The woven fabric used is preferably woven fiberglass fabric or teflon.
U.S. Pat. No. 4,443,559 relates to a catalytic distillation structure. The structure serves both as catalyst and as distillation packing. In the structure, the catalytic material having a particle size in the range from 0.25 to 1 mm is present in porous containers such as containers of woven fabric, wire mesh or woven polymer fabrics. These catalyst pockets are arranged in a matrix in such a way that at least 70% by volume of free space remains so that the catalyst bed can expand and contract. A plurality of catalytic reactions is indicated.
U.S. Pat. No. 4,242,530 relates to a process for separating isobutene from C
4
streams. The isobutene is catalytically polymerized or dimerized and separated off from the bottoms of the column. The distillation column is charged with an acid catalyst on a support. The catalyst is enclosed in pockets of woven fabric which are in turn surrounded by an open-mesh knitted fabric of steel wire. This wire mesh forms the support of the catalyst and allows the passage of the steam through the catalyst pockets. In particular, use is made of an acid cation-exchange fixed-bed catalyst.
EP-A1-0 631 813 relates to a catalytic fixed-bed reactor. The fixed-bed reactor contains stacked packing elements which form cushion-like packing parts having walls permeable to the distillation medium. These closed cushion-like packing parts contain the catalyst in the form of granules. The granules are introduced into the packing elements, for example, from above via a vibrating apparatus.
EP-B1-0 201 614 relates to a reactor for carrying out heterogenous, catalyzed chemical reactions. The catalyst here comprises corrugated plates arranged parallel to the main flow axis of the reactor, the corrugation being inclined at an angle to the main flow axis and being aligned in opposite directions in adjacent plates. A band-like, at least partially corrugated catalyst body is inserted in such a way that it can be removed between adjacent plates. The catalyst body can here be made, for example, of glass metal, woven wire fabric or knitted wire fabric. The catalyst body can consist entirely of a catalytically active material or be catalytically activated on the surface.
EP-B1-0 068 862 relates to a packing module for a catalyst having an ordered bed. The catalyst bed comprises alternate layers of flat and corrugated sheets which are rolled out into a roll. The bed has passages for fluid between the flat and corrugated sheets.
The flat sheet comprises a woven, knitted or felted cloth of a wick-like textile material which is hydrophilic in respect of the liquid in a gas-liquid transfer reaction to be carried out. The corrugated sheet comprises an open-mesh material which is hydrophobic in respect of the liquid and can comprise catalyst crystallites of at least one element of group VIII of the Periodic Table. The crystallites are here dispersed in the porous matrix and are partially enclosed so that the porous matrix essentially blocks contact of the liquid with the crystallites but makes possible contact with the gas under liquid in vapor form. Matrices of this type which are described are polytetrafluoroethylane with a catalyst comprising platinum crystallites which are supported on carbon particles having a high surface area. The catalytically active Pt/C particles are applied in the form of an aqueous suspension of Pt/C powder to the hydrophobic polymer and fixed by drying at from 60° C. to 200° C. and subsequent sintering at 365° C. As gas-liquid transfer reaction, mention is made of the hydrogen isotope exchange between hydrogen and liquid water.
EP-B1-0 433 223 relates to catalyst bodies and a reactor for carrying out a reaction heterogeneously. The catalyst body here has a support structure in the form of static mixer elements which are formed of a metal skeleton or can comprise a ceramic layer. A washcoat is applied to this support structure. The actual catalyst is located on the surface of the washcoat. The support structure can consist of one piece. Specific heterogeneous, catalytic reactions are not described.
Mechanical stressing of washcoated catalyst bodies tends to result in destruction of the applied layers which can become detached owing to inadequate adhesive strength.
In the case of the catalysts having granulated catalyst beds in packing elements such as woven fabric pockets, abrasion occurs particularly during charging of the catalytic distillation apparatus and when bumps occur during operation addition, higher pressure drops occur in beds than in the surroundings which leads to poor radial mixing in the reactor, to inhomogeneous concentration profiles and frequently to undesired leakage past the catalyst.
It is an object of the present invention to provide a catalyst for catalytic distillation in which a heterogeneously catalyzed reaction is combined with a distillation or rectification over a catalyst packing. A further object of the invention is the provision of a suitable catalyst system for catalytic distillation which avoids the disadvantages mentioned above. A further object of the invention is the provision of a reactor for catalytic distillation in which the catalyst packing can easily be changed. Another object of the invention is the provision of a process for catalytic hydrogenation.
We have found that these objects are achieved by the use of a catalyst packing which can be produced by vapor deposition and/or sputtering of at least one substance active as catalyst and/or promotor onto woven or knitted fabrics or sheets as support material in a process for catalytic distillation in which a heterogeneously catalyzed reaction is combined with simultaneous distillation or rectification over the catalyst packing. Preferred embodiments are indicated in the subclaims. In addition, the objects are achieved by a reactor for catalytic distillation, which reactor comprises a distillation column which is packed with a catalyst packing as described above. Furthermore, the objects are achieved by a process for catalytic hydrogenation using the catalyst packing.
Support Material
As support material for the catalysts used according to the present invention, it is possible to use a variety of sheets and woven or knitted fabrics, as well as knitted fabrics. Suitable woven wire fabrics are, according to an embodiment of the invention, woven fabrics of weavable metal wires such as iron, spring steel, brass, phosphor bronze, pure nickel, Monel, aluminum, silver, nickel silver, nickel, nichrome, chromium steel, stainless, acid-resistant and highly heat-resistant chromium nickel steels or titanium.
It is likewise possible to use woven fabrics of inorganic materials such as Al
2
O
3
and/or SiO
2
.
Synthetic wires and woven fabrics of plastics can also be used according to an embodiment of the invention. Examples are polyamides, polyester
Brocker Franz Josef
Erdbrugger Cristina Freire
Flick Klemens
Kaibel Gerd
Meyer Gerald
BASF - Aktiengesellschaft
Keil & Weinkauf
Yildirim Bekir L.
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