Multi-Purpose Catalytic Distillation Column and Etherification Process Using Same

~™ ii 1 1 mi ii ii i ii mi ii in ii i ii (19) J European Patent Office

Office europeen des brevets (11) EP 0 643 033 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) int. CI.6: C07C 43/04, C07C 41/06, of the grant of the patent: C07C 41/42, B01D3/00 06.05.1998 Bulletin 1998/19

(21) Application number: 94306447.7

(22) Date of filing: 01.09.1994

(54) Multi-purpose catalytic distillation column and etherif ication process using same Katalytischer Destillationsreaktor fur verschiedene Anwendungen und ein Etherifizierungsverfahren unter Verwendung dieses Reaktors Reacteur de distillation catalytique a usage multiple et un procede d'etherification utilisant celui-ci

(84) Designated Contracting States: • Adams, John R. BE DE ES FR GB IT NL SE Houston, Texas 77062 (US)

(30) Priority: 09.09.1993 US 118311 (74) Representative: Smaggasgale, Gillian Helen et al (43) Date of publication of application: Mathys & Squire, 15.03.1995 Bulletin 1995/11 100 Gray's Inn Road London WC1X8AL(GB) (73) Proprietor: CHEMICAL RESEARCH & LICENSING (56) References cited: COMPANY EP-A- 0197 348 EP-A- 0 455 029 Pasadena, Texas 77507 (US) WO-A-93/19032 DE-A-3 813 689 GB-A-2 265145 US-A-5196 612 (72) Inventors: US-A-5 243102 • Hickey, Thomas P. Houston, Texas 77068 (US)

CO CO CO o CO Note: Within nine months from the publication of the mention of the grant of the European patent, give CO any person may notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in o a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. Q_ 99(1) European Patent Convention). LU Printed by Xerox (UK) Business Services 2.16.2/3.4 EP 0 643 033 B1

Description

BACKGROUND OF THE INVENTION

5 Field of the Invention

The present invention relates to a multi-purpose catalytic distillation column and the use of the column to produce an ether from the reaction of an isoolef in with an alcohol. More particularly the invention relates to the production of tertiary amyl methyl ether by the reaction of the isoamylenes contained within a cracked naphtha stream with methanol in 10 a distillation column reactor which removes the C6+ fraction, sweetens the feed by removing mercaptans, removes the nitriles in the feed, selectively hydrogenates the dienes in the feed and reacts the isoamylenes with methanol to produce tertiary amyl methyl ether.

Related Art 15 The C5 refinery cut is valuable as a gasoline blending stock or as source of isoamylene to form an ether by reaction with lower alcohols. Tertiary amyl methyl ether (TAME) is rapidly becoming valuable to refiners as a result of the recently passed Clean Air Act which sets some new limits on gasoline composition. Some of these requirements are (1) to include a certain amount of "oxygenates", such as methyl tertiary butyl ether (MTBE), TAME or ethanol, (2) to reduce 20 the amount of olefins in gasoline, and (3) to reduce the vapor pressure (volatility). In most C5 cuts the isoamylene suitable for the production of TAME is frequently present in small quantities, e.g. less than 1 5%, whereas there are other C5 olefin isomers and enough dienes and acetylenes to inhibit the etherif ication process. It is an advantage of the present invention that the contaminants such as the diolef ins, acetylenes, mercaptans and nitriles are removed before the etherif ication in the single distillation column reactor. It is also an advantage that the 25 stream recovered from the column containing the ether is suitable without further treatment to be used as an octane blending stock. These and other advantages and features of the present invention become clear from the following descriptions. US-A-5243102 describes a process for the production of ethers suitable for use as high octane oxygenate additives for motor fuels in a multistage catalytic distillation process. The heavier paraffins and olefins in the olefin feed stream 30 and a first product ether are concentrated into the bottoms stream of the first catalytic distillation zone. The bottoms stream and additional alcohol is passed into a second catalytic distillation zone in which the heavier isolefin is con- sumed in the production of a second ether. US-A-5196612 describes a process for producing ethers suitable for use as high octane oxygenate additives for motor fuels. The ethers are produced by a catalytic distillation process in which a mixture of C5-plus isolefin isomers 35 and an alcohol are charged to a catalytic distillation zone containing both etherification and double bond isomerization catalysts. EP-A-0455029 relates to the reaction of a hydrocarbon stream containing olefins with alkanols in the presence of hydrogen and a catalyst to form ethers useful as fuel components. EP-A-01 97348 describes the production of gum-free engine fuel components obtained from crude hydrocarbon 40 mixtures containing olefins by simultaneous reaction in the liquid phase at 30-1 40°C with alkanols and hydrogen on a suitable catlyst. DE-A-3813689 descibes the reaction of branched-chain olefins with alkanols in the presence of hydrogen and a catalytically active layered clay.

45 SUMMARY OF THE INVENTION

Briefly the present invention comprises a single distillation column reactor wherein a cracked light naphtha stream is fed to produce tertiary amyl methyl ether. The distillation column reactor acts as a depentanizer to remove the C6 and heavier fraction and because methanol is fed at the same time an azeotropic separation of the nitriles from the C5 por- 50 tion is effected. Suitable beds of catalytic distillation structure are arranged to achieve all of the desired reactions. A first bed selectively reacts some of the diolefins with mercaptans to produce heavier materials which can be removed with the C6 bottoms and selectively hydrogenates the diolefins in the feed and a second bed performs the etherification func- tion. According to the first aspect of the present invention there is provided a distillation column reactor comprising: a 55 lower stripping section containing inert distillation structure; a first distillation reaction zone disposed above said stripping section said first zone containing a first catalytic distillation structure comprising a supported hydrogenation catalyst; and a second distillation reaction zone disposed above said first distillation reaction zone said second zone containing a second catalytic distillation structure comprising an etherification catalyst.

2 EP 0 643 033 B1

The invention also relates to a process for the treatment of a light cracked naphtha stream comprising isoamylene, said process comprising the steps of:

(a) feeding a light cracked naphtha stream to a distillation column reactor having a stripping section and two distil- 5 lation reaction zones in series; (b) concurrently feeding a stream containing a hydrogen to said distillation column reactor; (c) separating a C6 and heavier boiling fraction from said light cracked naphtha in said stripping section while boiling a C5 boiling fraction containing mercaptan and diolefin contaminants up into a first distillation reaction zone comprising a hydrogenation catalyst in the form of a catalytic distillation structure; 10 (d) concurrently in said distillation reaction zone;

(i) reacting said mercaptans contained within said C5 boiling fraction with a portion of said diolefins contained within said C5 boiling fraction to produce sulfides having a boiling range higher than said C5 boiling fraction; (ii) reacting the remainder of said diolefins and any acetylenes contained within said C5 boiling fraction with a 15 portion of said hydrogen; and (iii) separating said C5 boiling fraction from said sulfides by fractional distillation;

(e) feeding a stream containing methanol to said distillation column reactor to form a methanol/C5 adeotrope in said first distillation reaction zone, said azeotrope having a lower boiling point than said C5 boiling fraction; 20 (f) boiling said azeotrope up into a second distillation reaction zone comprising an etherification catalyst in the form of a catalytic distillation structure wherein a portion of the isoamylenes contained within said azeotrope react with a portion of the methanol contained within said azeotrope to form tertiary amyl methyl ether; (g) removing said tertiary amyl methyl ether, said C6 and heavier boiling fraction and said sulfides from said distillation column reactor as bottoms. 25 The hydrogenation catalyst preferably comprises an alumina supported particulate palladium oxide catalyst. The catalyst may be contained within an open mesh container coiled within a demister wire support. In a preferred arrange- ment the etherification catalyst is contained in pockets on a cloth belt and wound together with a demister wire support. The etherification catalyst is preferably an acidcation exchange resin catalyst. 30 The lower stripping section of the distillation column reactor is preferably contained in a separate vessel and the reactor preferably further comprises, a first conduit to carry liquid from the first distillation reaction zone to the stripping section and a second conduit to carry vapor from the stripping section to the first distillation reaction zone. The preferred process of the invention for the production of tertiary amyl methyl ether comprises the steps of:

35 (a) feeding a first stream comprising a light cracked naphtha to a distillation column reactor having a stripping section and a first distillation reaction zone containing a hydrogenation catalyst in the form of a catalytic distillation structure and a second distillation reaction zone containing an acid cation exchange resin in the form of a catalytic distillation structure; (b) concurrently feeding a second stream containing hydrogen and a third stream containing methanol to said dis- 40 tillation column reactor; (c) separating the C6 and heavier boiling fraction from said light cracked naphtha in said stripping section while boiling the C5 fraction up into said first distillation reaction zone; (d) concurrently in said first distillation reaction zone:

45 (i) removing sulfur compounds, which are primarily mercaptans by reacting the mercaptans contained within said C5 boiling fraction to produce sulfides having a boiling range higher than said C5 boiling fraction; (ii) reacting the remainder of the diolefins and any acetylenes contained within said C5 boiling fraction with a portion of said hydrogen to reduce the unsaturation and isomerizing a portion of isoolefins; and (iii) forming a Cs/methanol azeotrope and boiling said azeotrope up into said second distillation reaction zone so while separating said sulfides and any nitrogen containing compounds contained within said C5 fraction by fractional distillation;

(e) concurrently in said second distillation reaction zone:

55 (i) reacting the isoamylenes contained within said azeotrope with methanol contained within said azeotrope to form tertiary amyl methyl ether, and (ii) separating said tertiary amyl methyl ether from unreacted C5's and methanol by fractional distillation;

3 EP 0 643 033 B1

(f) withdrawing unreacted C5's, unreacted methanol and unreacted hydrogen from said distillation column reactor as overheads; and (g) withdrawing said C6 and heavier fraction, said tertiary amyl methyl ether, said sulfides and said nitrogen containing compounds from said distillation column reactor as bottoms. 5 Any nitrogen containing compounds within the C5 fraction are preferably removed with the bottoms. The methanol may be fed above the second distillation reaction zone. The heavier boiling components of step (c) above include TAME, the sulfides and nitriles which ultimately leave the reactor column in the bottoms. 10 BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a simplified schematic representation of a catalytic distillation column configured for the present invention. 15 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The C5's in the feed to the present TAME unit are contained in a single "light naphtha" cut which may contain eve- rything from C5's through C8's and higher. This mixture can easily contain 150 to 200 components. Mixed refinery 20 streams often contain a broad spectrum of olef inic compounds. This is especially true of products from either catalytic cracking or thermal cracking processes. Refinery streams are usually separated by fractional distillation, and because they often contain compounds that are very close in boiling points, such separations are not precise. A C5 stream, for instance, may contain C4's and up to C8's. These components may be saturated (alkanes), unsaturated (mono-olefins), or poly-unsaturated (diolefins). Additionally, the components may be any or all of the various isomers of the individual 25 compounds. Such streams typically contain 1 5 to 30 weight % of the isoamylenes. Several of the minor components (diolefins) in the feed will react slowly with oxygen during storage to produce "gum" and other undesirable materials. However, these components also react very rapidly in the TAME process to form a yellow, foul smelling gummy material. Thus it is seen to be desirable to remove these components whether the "light naphtha" cut is to be used only for gasoline blending by itself or as feed to a TAME process. 30 Such refinery streams also contain small amounts of sulfur and nitrogen compounds which must be removed. The sulfur compounds are generally found in a light cracked naphtha stream as mercaptans which react with the etherification catalyst to inhibit the etherification reaction. Removal of sulfur compounds is generally termed "sweetening" a stream. The nitrogen compounds normally exist as nitriles which may hydrolyze forming compounds which are basic in nature and can neutralize the acidic nature of the etherification catalyst. Thus, the removal of the mercaptans and 35 nitriles is desirable. The nature of sulfur compounds present is also dependent upon the boiling range of the distillate. In a light naphtha (43-121°C (110-250°F) boiling range), the predominant sulfur compounds are mercaptans. Typical of the mercaptan compounds which may be found to a greater or lesser degree in a light cracked naphtha are: methyl mercaptan (b.p. 6°C (43°F)), ethyl mercaptan (b.p. 37°C (99°F)), n-propyl mercaptan (b.p. 68°C (154°F)), iso-propyl mercaptan (b.p. 57- 40 60°C (135-140°F)), iso-butyl mercaptan (b.p. 88°C (190°F)), tert-butyl mercaptan (b.p. 64°C (147°F)), n-butyl mercaptan (b.p. 98°C (208°F)), sec-butyl mercaptan (b.p. 95°C (203°F), iso-amyl mercaptan (b.p. 121°C (250°F)), n-amyl mercaptan (b.p. 126°C (259°F)), a-methylbutyl mercaptan (b.p. 112°C (234°F)), a-ethylpropyl mercaptan (b.p. 145°C (293°F)), n-hexyl mercaptan (b.p. 151°C (304°F)), 2-mercapto hexane (b.p. 140°C (284°F)), and 3-mercapto hexane (b.p. 57°C(135°F)). 45 Typical diolefins in the C5 boiling range fraction include: isoprene (2-methyl butadiene-1,3), cis and trans piperylenes (cis and trans 1 ,3-pentadienes), and minor amounts of butadienes. A suitable feed for the present invention would be a light naphtha cut comprising primarily C5 hydrocarbons comprising normal alkanes, normal alkenes, isoalkanes and isoalkenes and very minor amounts of contaminant compounds containing sulfur and nitrogen. so As described above there are concurrently at least seven functions being carried out in the catalytic distillation reactor as described, i.e.

1. etherification; 2. distillation of unreacted C5 components from the etherization; 55 3. separation of C5 components from nitrile contaminants by azeotrope distillation of the alcohol and the C5's; 4. hydrogenation of the diolefins and acetylenes; 5. removal of sulfur compounds including the reaction of mercaptans with diolefins; 6. isomerization of isoolefins;

4 EP 0 643 033 B1

7. distillation of C5's from the sulfides; 8. distillation of the lighter components from the ether product, the C6's and heavier hydrocarbons, nitriles and sulfides.

5 Referring now to the figure the column and process can be understood. The distillation column, reactor 1 0 is shown to be generally cylindrical in shape and oriented vertically. A methanol inlet 2 is provided near the lower end of zone 1 2. The lower portion 20 of the vessel contains inert distillation structures such as inert packing, sieve trays, bubble cap trays or the like. Section 20 is the stripping section for separating the C6 and higher boiling material from the C5 and lower boiling material in the light cracked naphtha. A light naphtha inlet 1 is directly above the stripping section 20. 10 Hydrogen may be fed separately but is preferably fed with the light naphtha. Directly above the stripping section within the column 10 is a first distillation reaction zone 7 containing hydrogenation catalyst prepared as a first catalytic distillation structure. Section 7 is the hydrogenation zone where the diolefins and acetylenes are selectively hydrogenated, mercaptans are reacted with diolefins and isoolefins are isomerized. The isomerization under the conditions of hydrogenation is of the bond type and very little, if any, skeletal isomerization 15 occurs in the present process. The sulfides formed from the reaction of the mercaptans with the diolefins are higher boiling than the C5's and are distilled downward and removed with the bottoms. Hydrogenation is the reaction of hydrogen with a carboncarbon multiple bond to "saturate" the compound. This reaction is usually carried out at super atmospheric pressures and moderate temperatures using an excess of hydrogen over a metal catalyst. Among the metals known to catalyze the hydrogenation reaction are platinum, rhenium, cobalt, 20 molybdenum, nickel, tungsten and palladium. Generally, commercial forms of catalyst use supported oxides of these metals. The oxide is reduced to the active form either prior to use with a reducing agent or during use by the hydrogen in the feed. These metals also catalyze other reactions, most notably dehydrogenation at elevated temperatures. Addi- tionally they can promote the reaction of olefinic compounds with themselves or other olefins to produce dimers or oli- gomers as residence time is increased. 25 Selective hydrogenation of hydrocarbon compounds has been known for quite some time. Peterson, et al in "The Selective Hydrogenation of Pyrolysis Gasoline" presented to the Petroleum Division of the American Chemical Society in September of 1962, discusses the selective hydrogenation of C4 and higher diolefins. Boitiaux, et al in "Newest Hydrogenation Catalyst", Hydrocarbon Processing. March 1985, presents an over view of various uses of hydrogenation catalysts, including selective hydrogenation, utilizing a proprietary bimetallic hydrogenation catalyst which is also 30 suitable in the present invention. The reactions of interest in the first distillation zone 7 are:

(1) isoprene (2-methyl butadiene-1,3) + hydrogen to 2-methyl butene-1 and 2-methyl butene-2; (2) cis- and trans 1 ,3-pentadienes (cis and trans piperylenes) + hydrogen to pentene-1 and pentene-2; 35 (3) 1 ,3-butadiene to butene-1 and butene-2, (4)

40 C H2 | RSH + R1C=C-C=C-R2 - R-S-C-C=C-R2 Pd

45 and (5) 3-methyl butene-1 <^ 2-methyl butene-1/2-methyl butene-2

A catalyst suitable for the hydrogenation section 7 is 0.34 wt% Pd on 3 to 8 mesh Al203 (alumina) spheres, supplied so by United Catalysts Inc. designated as G-68C. Typical physical and chemical properties of the catalyst as provided by the manufacturer are as follows:

TABLE I Designation G-68C Form Sphere

5 EP 0 643 033 B1

TABLE I (continued) Nominal size 5x8 mesh Pd. wt% 0.3 (0.27-0.33) Support High purity alumina

The catalyst is believed to be the hydride of palladium which is produced during operation. The hydrogen rate to the reactor must be sufficient to maintain the catalyst in the active form because hydrogen is lost from the catalyst by 10 hydrogenation, but kept below that which would cause flooding of the column which is understood to be the "effectuat- ing amount of hydrogen " as that term is used herein. Generally the mole ratio of hydrogen to diolefins and acetylenes in the feed to the fixed bed of the present invention will be at least 1 .0 to 1 .0 preferably 2.0 to 1 .0. Other suitable catalysts for both the hydrogenation/isomerization and the etherification include a macroporous or gelatinous acid cation exchange resin in the H+ form which has been charged with a metal of Groups VI, VII or VIII of 15 the periodic table of elements as described in U.S. Pat. No. 4,330,679. The catalyst must be suitably supported and spaced within the column to act as a catalytic distillation structure. In the preferred embodiment the catalyst is contained in a woven wire mesh structure as disclosed in U.S. 5266546 to which reference may be made for more detailed information, structures suitable for use in the present process are those described in U. S. Pat. No.s 4,731,229 and 5,073,236 and European Patent No. 0396650. 20 Above the hydrogenation section within the column 10 the second distillation reaction zone 12 contains an acid cation exchange resin catalyst in the form of a second catalytic distillation structure. In this section 12 the isoamylenes are reacted with methanol to form tertiary amyl methyl ether (TAME) which is higher boiling than the C5's and is distilled downward and removed with the C6 and heavier materials via line 8. Zone 12 may be directly above zone 7 or there may be intervening inert distillation structures (not shown) as described in zone 20. 25 Additionally, methanol and the C5's form an azeotrope that is lower boiling than the C5's and the nitrile contaminants. It is this azeotrope that is boiled up from the first reaction distillation zone 7 into the second reaction distillation zone 12. The isoamylenes in the azeotrope react with the methanol to form the TAME. In the case of the C5's, the azeotrope contains about 12 wt% methanol, and the boiling point of the azeotrope is 5 to 8 degrees C (1 0 to 1 5 degrees F) below that of the corresponding C5's. Thus, if the net flow of methanol into the col- 30 umn (allowing for that reacting in the column) is less than the azeotrope concentration in the distillate, the methanol concentration in the reaction distillation zone will be relatively quite low, about 1%. If the net methanol flow into the column is higher than the azeotrope, the methanol concentration will increase (60% has been measured) until methanol leaves with the TAME bottoms product. Neither case is desirable, because at low concentration the conversion of isoamylene to TAME is low, whereas at high concentrations the TAME purity is affected by the presence of the excess methanol. 35 Thus the rate of methanol feed is constantly adjusted to maintain the amount of methanol in the column above the azeotrope but below the excess to appear in the bottoms. In one embodiment this may be adjusted by feeding a portion of the methanol above the etherification catalyst bed via line 1 4. The methanol/C5 azeotrope (less the nitrogen compounds and sulfides) is boiled up into the etherification section 12 which contains an acid cation exchange resin catalyst in the form of a catalytic distillation structure. The etherif ica- 40 tion is, for example, that described in U.S. Pat. No. 4,336,407, to which reference may be made for detailed infomation. Generally the size of the particles of resin are such that a fine mesh such as a cloth container is preferred. Such a container and catalytic distillation structure are disclosed in U.S. Patent No. 4,443,559, to which reference may be made for detailed information, and is shown to comprises a fiber glass cloth belt with a plurality of pockets containing the resin catalyst. The cloth belt is wound with demister wire to make the distillation structure. 45 The unreacted methanol, C5's, and hydrogen are taken as overheads via outlet 5 and passed through condenser 13 where the condensible materials are condensed and then collected via line 4 in accumulator-separator 11. A third set of inert distillation structures 15 is optionally position above the second reaction distillation zone 12. The light incondensibles, including the hydrogen are removed from the accumulator via line 3. Liquid is removed form the separator via line 9 with a portion being recycled to the column 10 via line 6 as reflux. so The TAME is not generally separated from the heavier components, but all are used directly as octane blending stocks.

Claims

55 1. A distillation column reactor (10) comprising: a lower stripping section (20) containing inert distillation structure; a first distillation reaction zone (7) disposed above said stripping section said first zone containing a first catalytic distillation structure comprising a supported hydrogenation catalyst; and a second distillation reaction zone (1 2) disposed above said first distillation reaction zone said second zone containing a second catalytic distillation structure

6 EP 0 643 033 B1

comprising an etherification catalyst.

2. The distillation column according to Claim 1 wherein said hydrogenation catalyst comprises an alumina supported particulate palladium oxide catalyst. 5 3. The distillation column according to Claim 1 or 2 wherein said hydrogenation catalyst is contained within an open mesh container coiled within a demister wire support.

4. The distillation column according to Claim 1 wherein said etherification catalyst comprises an acid cation exchange 10 resin catalyst.

5. A distillation column reactor according to any one of Claims 1 to 4 wherein said etherification catalyst is contained in pockets on a cloth belt and wound together with demister wire support.

15 6. A distillation column reactor according to any one of Claims 1 to 5 wherein said lower stripping section (20) is contained in a separate vessel and said distillation column reactor (10) further comprises, a first conduit to carry liquid from said first distillation reaction zone to said stripping section and a second conduit to carry vapor from said stripping section to said first distillation reaction zone.

20 7. A process for the treatment of a light cracked naphtha stream comprising isoamylene, said process comprising the steps of:

(a) feeding a light cracked naphtha stream to a distillation column reactor (10) having a stripping section (20) and two distillation reaction zones (7, 12) in series; 25 (b) concurrently feeding a stream containing hydrogen to said distillation column reactor; (c) separating a C6 and heavier boiling fraction from said light cracked naphtha in said stripping section while boiling a C5 boiling fraction containing mercaptan and diolefin contaminants up into a first distillation reaction zone (7) comprising a hydrogenation catalyst in the form of a catalytic distillation structure; (d) concurrently in said distillation reaction zone; 30 (i) reacting said mercaptans contained within said C5 boiling fraction with a portion of said diolefins contained within said C5 boiling fraction to produce sulfides having a boiling range higher than said C5 boiling fraction; (ii) reacting the remainder of said diolefins and any acetylenes contained within said C5 boiling fraction 35 with a portion of said hydrogen; and (iii) separating said C5 boiling fraction from said sulfides by fractional distillation;

(e) feeding a stream containing methanol to said distillation column reactor to form a methanol/C5 azeotrope in said first distillation reaction zone, said azeotrope having a lower boiling point than said C5 boiling fraction; 40 (f) boiling said azeotrope up into a second distillation reaction zone (12) comprising an etherification catalyst in the form of a catalytic distillation structure wherein a portion of the isoamylenes contained within said azeotrope react with a portion of the methanol contained within said azeotrope to form tertiary amyl methyl ether; (g) removing said tertiary amyl methyl ether, said C6 and heavier boiling fraction and said sulfides from said distillation column reactor as bottoms. 45 8. The process according to Claim 7 wherein any nitrogen containing compounds within said C5 fraction are removed with said bottoms.

9. The process according to Claim 7 or 8 wherein a portion of said methanol is fed above the second distillation reac- 50 tion zone (12).

10. A process according to any one of Claims 7 to 9 for the production of tertiary amyl methyl ether wherein the etherification catalyst is an acid cation exchange resin.

55 Patentanspruche

1. Destillationskolonnenreaktor (10), umfassend: einen unteren Rektifizierbereich (20), der eine inerte Destillations- struktur enthalt, eine uber dem Rektifizierbereich angeordnete, erste Destillationsreaktionszone (7), wobei die

7 EP 0 643 033 B1

erste Zone eine erste, einen getragerten Hydrierungskatalysator aufweisende katalytische Destillationsstruktur enthalt, und eine uber der ersten katalytischen Destillationsreaktionszone angeordnete, zweite katalytische Destil- lationsreaktionszone (12), wobei die zweite Zone einen einen Etherif izierungskatalytsator aufweisende, zweite katalytische Destillationsstruktur enthalt.

2. Destillationskolonne gemaB Anspruch 1 , bei der der Hydrierungskatalysator ein auf Aluminiumoxid getragertes, teilchenformiges Palladiumoxid als Katalysator aufweist.

3. Destillationskolonne gemaB Anspruch 1 oder 2, bei dem der Hydrierungskatalysator in einem offenmaschigen Behalter enthalten ist, der in einem Tropfenabscheiderdraht als Trager verknault ist.

4. Destillationskolonne gemaB Anspruch 1 , bei der der Etherif izierungskatalysator ein saures Kationenaustauscher- harz als Katalysator umfaBt.

5. Destillationskolonnenreaktor gemaB einem der Anspruche 1 bis 4, bei dem der Etherifizierungskatalysator in den Taschen eines Tuchstreifens enthalten und mit einem Tropfenabscheiderdraht als Trager verwunden ist.

6. Destillationskolonnenreaktor gemaB einem der Anspruche 1 bis 5, bei dem der untere Rektifizierbereich (20) in einem separaten Kessel enthalten ist und der Destillationskolonnenreaktor (10) zusatzlich eine erste Leitung zum Fuhren der Flussigkeit aus der ersten Destillationsreaktionszone zum Rektifizierbereich und eine zweite Leitung zum Fuhren des Dampfes aus dem Rektifizierbereich in die erste Destillationsreaktionszone aufweist.

7. Verfahren zur Behandlung eines Isoamylen enthaltenden, leichten, gecrackten Naphthastroms, wobei das Verfah- ren die Schritte umfaBt:

(a) Einspeisen eines leichten, gecrackten Naphthastroms in einen Destillationskolonnenreaktor (10) mit einem Rektifizierbereich (20) und zwei Destillationsreaktionszonen (7, 12) in Serie, (b) gleichzeitiges Einspeisen eines Wasserstoff enthaltenden Stroms in den Destillationskolonnenreaktor, (c) Abtrennen einer C6- und hoher siedenden Fraktion vom leichten, gecrackten Naphtha im Rektifizierbereich, wahrend eine C5-Siedefraktion, die Mercaptan- und Olefinverunreinigungen enthalt, in eine einen Hydrie- rungskatalysator in Form einer katalytischen Destillationsstruktur enthaltende erste Destillationsreaktonszone gekocht wird, (d) in der Destillationsreaktionszone gleichzeitiges

(i) Umsetzen der in der C5-Siedefraktion enthaltenen Mercaptane mit einem Teil der in der C5-Siedefrak- tion enthaltenen Diolefine zur Erzeugung von Sulfiden mit einem hoheren Siedebereich als die C5-Siede- fraktion, (ii) Umsetzen des Rests der Diolefine und jeglicher, in der C5-Siedefraktion enthaltener Acetylene mit einem Anteil der Wasserstoffs und (iii) Abtrennen der C5-Siedefraktion mittels fraktionierter Destination von diesen Sulfiden,

(e) Einspeisen eines Methanol enthaltenen Stroms in den Destillationskolonnenreaktor zur Bildung eines Methanol / C5-Azeotrops in der ersten Destillationsreaktionszone, wobei das Azeotrop einen niedrigeren Sie- depunkt als die C5-Siedefraktion aufweist, (f) Absieden des Azeotrops in eine zweite, einen Etherifizierungskatalysator in Form einer katalytischen Destil- lationsstruktur enthaltene Destillationsreaktionszone (12), in der ein Teil der in dem Azeotrop enthaltenen Iso- amylene mit einem Teil des in dem Azeotrop enthaltenen Methanols zur Bildung von tert.-Amylmethylether reagiert, und (g) Entfernen des tert.-Amylmethylethers, der C6- und hoher siedenden Fraktionen und der Sulfide als Boden- produkte aus dem Destillationskolonnenreaktor.

8. Verfahren gemaB Anspruch 7, bei dem jegliche Stickstoff enthaltenden Verbindungen in der C5-Fraktion mit dem Bodenprodukt entfernt werden.

9. Verfahren gemaB Anspruch 7 oder 8, bei dem ein Teil des Methanols uber der zweiten Destillationsreaktionszone (12) eingespeist wird.

10. Verfahren gemaB einem der Anspruche 7 bis 9 zur Erzeugung von tert.-Amylmethylether, bei dem der Etherif izie-

8 EP 0 643 033 B1

rungskatalysator ein saures Kationenaustauscherharz ist.

Revendications

5 1 . Reacteur a colonne de distillation (1 0) comprenant une section inferieure de separation (20) contenant une structure inerte de distillation; une premiere zone de reaction avec distillation (7) disposee au-dessus de cette section de separation, cette premiere zone contenant une premiere structure de distillation catalytique comprenant un catalyseur d'hydrogenation supporte; et une seconde zone de reaction avec distillation (12) disposee au-dessus de cette premiere zone de reaction avec distillation, cette seconde zone contenant une seconde structure de dis- 10 tillation catalytique comprenant un catalyseur d'etherification.

2. Colonne de distillation suivant la revendication 1 , dans laquelle ce catalyseur d'hydrogenation comprend un catalyseur a base d'oxyde de palladium particulaire supporte sur de I'alumine.

15 3. Colonne de distillation suivant les revendications 1 ou 2, dans laquelle ce catalyseur d'hydrogenation est contenu a I'interieur d'un recipient a maille ouverte enroule a I'interieur d'un support de f il metallique demister.

4. Colonne de distillation suivant la revendication 1 , dans laquelle ce catalyseur d'etherification comprend un catalyseur de type resine d'echange de cation acide. 20 5. Colonne de distillation suivant I'une quelconque des revendications 1 a 4, dans laquelle ce catalyseur d'etherification est contenu dans des poches sur une bande de tissu et enroule avec un support metallique demister.

6. Colonne de distillation suivant I'une quelconque des revendications 1 a 5, dans laquelle cette section inferieure de 25 separation (20) est contenue dans un recipient separe et ce reacteur a colonne de distillation (10) comprend de plus, un premier conduit pour transporter le liquide provenant de cette premiere zone de reaction avec distillation vers cette section de separation et un second conduit pour transporter la vapeur de cette section de separation vers cette premiere zone de reaction avec distillation.

30 7. Procede pour le traitement d'un courant de naphta craque leger comprenant de I'isoamylene, ce procede comprenant les etapes de :

(a) charge d'un courant de naphta craque leger dans un reacteur a colonne de distillation (10) ayant une section de separation (20) et deux zones de reaction avec distillation (7, 12) en serie; 35 (b) concurremment, charge d'un courant contenant de I'hydrogene dans ce reacteur a colonne de distillation; (c) separation d'une fraction d'ebullition en C6 et plus de ce naphta craque leger dans cette section de separation, tandis qu'une fraction d'ebullition en C5 contenant des contaminants de type mercaptan et diolefine monte par ebullition dans une premiere zone de reaction avec distillation (7) comprenant un catalyseur d'hydrogenation sous la forme d'une structure de distillation catalytique; 40 (d) concurremment dans cette zone de reaction avec distillation:

(i) reaction de ces mercaptans contenus dans cette fraction d'ebullition en C5 avec une partie de ces dio- lefines contenues dans cette fraction d'ebullition en C5 pour produire des sulfures ayant une gamme d'ebullition superieure a celle de cette fraction d'ebullition en C5; 45 (ii) reaction du restant de ces diolef ines et de quelconques acetylenes contenus dans cette fraction d'ebullition en C5 avec une partie de cet hydrogene; et (iii) separation de cette fraction d'ebullition en C5 de ces sulfures par distillation fractionnee;

(e) charge d'un courant contenant du methanol dans ce reacteur a colonne de distillation pour former un azeo- 50 trope methanol/C5 dans cette premiere zone de reaction avec distillation, cet azeotrope ayant un point d'ebullition inferieur a celui de cette fraction d'ebullition en C5; (f) montee par ebullition de cet azeotrope dans une seconde zone de reaction avec distillation (1 2) comprenant un catalyseur d'etherification sous la forme d'une structure de distillation catalytique dans laquelle une partie des isoamylenes contenus dans cet azeotrope reagit avec une partie du methanol contenu dans cet azeotrope 55 pour former de Tether t-amyl methylique; (g) elimination de cet ether t-amyl methylique, de cette fraction d'ebullition en C5 et plus, et de ces sulfures de ce reacteur a colonne de distillation en tant que fraction de queue.

9 EP 0 643 033 B1

8. Procede suivant la revendication 7, dans lequel de quelconques composes contenant de I'azote dans cette fraction en C5 sont elimines avec cette fraction de queue.

9. Procede suivant les revendications 7 ou 8, dans lequel une partie de ce methanol est chargee au-dessus de la seconde zone de reaction avec distillation (12).

10. Procede suivant I'une quelconque des revendications 7 a 9 pour la production d'ether t-amyl methylique, dans lequel le catalyseur d'etherification est une resine d'echange de cation acide.