EP2097159A1

EP2097159A1 - Adsorption composition and process for removing co from streams

Info

Publication number: EP2097159A1
Application number: EP07847460A
Authority: EP
Inventors: Stephan Hatscher; Michael Hesse
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-12-01
Filing date: 2007-11-28
Publication date: 2009-09-09
Also published as: JP2012110893A; JP5619788B2; US8236264B2; CN101547733A; TWI425985B; CN101547733B; WO2008065135A1; JP2010510879A; TW200835551A; US20090301301A1; KR20090086106A

Abstract

Carbon monoxide is removed from streams by adsorption on an adsorption composition comprising copper oxide, zinc oxide and aluminium oxide.

Description

Adsorption composition and method for removing CO from material streams

The present invention relates to an adsorption composition and a process for removing CO from material streams. In particular, the invention relates to an adsorption composition and a process for removing carbon monoxide from hydrocarbon streams.

In various fields of technology, it is important to have particularly pure material flows available. In this context, "pure" means that the material flow is free from constituents which have a disturbing effect on the intended use of the material flow, for example breathable air which must be free of toxic compounds and, for example, in the production of electronic components In order to avoid introducing contaminants that adversely affect the electronic properties of the components produced, it is often necessary to use particularly pure nitrogen or particularly pure argon as the protective gas, for example, catalytic chemical reactions, and catalysts are often very sensitive to poisoning For economic reasons, usually seeking to maximize the feed stream to be used per volume or mass of catalyst, even exceedingly small amounts of impurities in the feedstream can accumulate on the catalyst and poison it For olefin polymerization reactions on modern catalysts - for example, metallocene catalysts - olefin streams are needed that contain no more than a few ppb (parts per billion, ie, 10 " ⁹ parts of impurities per part of desired material) (" polymer grade "olefins). Olefins derived from typical olefins (steam crackers, fluid catalytic crackers, dehydrogenations, MTO processes ("methanol to olefins") usually contain much higher proportions (ppm or even per thousand) of impurities such as carbon monoxide or oxygen ("chemical grade "), these proportions must be reduced accordingly before use for polymerization.

Typically, the streams to be purified are air, nitrogen or argon or hydrocarbons such as ethylene, propylene, 1-butene, 2-butene, 1, 3-butadiene or styrene. Typical impurities that usually have to be removed are oxygen and carbon monoxide, and often also water, carbon dioxide, hydrogen, or else sulfur, arsenic or antimony compounds. Methods for removing such contaminants from streams are known.

The best known is the removal of carbon monoxide from oxygen-containing gas streams, for example from breathing air. This is usually done by catalytic conversion of carbon monoxide with oxygen, usually on copper-containing catalysts. The most widely used catalyst in this reaction is Hopcalite, originally developed for CO removal from breath in respiratory masks, for conversion of carbon monoxide with oxygen highly active copper-manganese mixed oxide, at which the highly toxic carbon monoxide converts with oxygen to carbon dioxide.

However, other uses of hopcalite and methods of purifying streams other than respiratory air are also known. Thus, WO 98/041 597 A1 discloses a process for the removal of alkynes, mono- or polyunsaturated hydrocarbons, sulfur, antimony or arsenic compounds, oxygen, hydrogen and carbon monoxide from streams by a sequence of two or three specific catalytic and absorptive process steps. EP 662 595 A1 teaches a process for removing hydrogen, carbon monoxide and oxygen from cold liquid nitrogen by contacting them with certain zeolites or other metal oxides, especially hopcalite. EP 750 933 A1 discloses a similar process for the removal of oxygen and carbon monoxide from cold nitrogen or cold noble gases by contacting them with metal oxides, in particular hopcalite. The angewende- th low temperatures below -40 ⁰ C but reaction with little or no catalytic occurs, oxygen and carbon monoxide are adsorbed on hopcalite and only react at higher temperatures, unless they are in the cold in a desorption away. EP 820 960 A1 discloses a method for removing oxygen and carbon monoxide from nitrogen or noble gases by inconsis- clock bring with metal oxides such as hopcalite, particularly at temperatures of 5 to 50 ⁰ C.

T.-J Huang and D.-H. Tsai, Catalysis Letters 87 (2003) 173-178 report studies on the influence of the degree of oxidation of copper on the oxidation of carbon monoxide. CU2O is more active overall than CuO, which is attributed to the higher mobility of oxygen in CU2O compared to Cu or CuO.

WO 02/094 435 A1 teaches a process for the oxidative removal of CO from ethylene at temperatures in the range of 70 to 1 10 ⁰ C to copper and zinc-containing nachkalzinierten copper (oxide), zinc oxide and alumina-containing catalysts. WO 02/47818 A1 discloses a process for the hydrogenation of maleic anhydride on such catalysts.

WO 02/026 619 A2 discloses a process for the removal of carbon monoxide by a water gas shift reaction and WO 03/051 493 A2 a process for the selective oxidation of carbon monoxide, in each case in gas streams containing carbon monoxide, oxygen and hydrogen, in particular in fuel cells, and each of catalysts containing copper, a platinum group metal and a reducible metal oxide on an oxidized support of activated aluminum, zirconia, titania, silica, zeolites or their combinations. The reducible metal oxide is selected from the group of oxides of Cr, V, Mo, Ce, Pr, Nd, Ti, Ni, Mn, Co and their combinations. US 6 238 640 B1 describes a process for removing carbon monoxide. xid from hydrogen-containing gas streams by reaction with steam and oxygen to carbon dioxide and hydrogen in the presence of a catalyst containing copper and alumina and at least one metal oxide of the group formed by zinc oxide, chromium oxide and magnesium oxide.

In these processes for the removal of carbon monoxide in the presence of oxygen by the reaction of carbon dioxide. This may be inert in subsequent processes or may even be an interfering contaminant. In the latter case, it is removed, and various methods are known for this as well. For example, CA 2 045 060 A1 teaches a process for the removal of carbon monoxide, carbon dioxide, hydrogen, oxygen and water vapor from inert gas streams at a temperature in the range from -30 ⁰ C to + 40 ⁰ C, in particular from -30 ⁰ C and 0 ⁰ C, wherein carbon monoxide is reacted to transition metal oxides such as hopcalite or copper-cobalt oxide to carbon dioxide and the latter is removed by adsorption on copper on an aluminum oxide support or nickel on an alumina or silica support.

However, in some applications, carbon monoxide needs to be removed other than by reaction with oxygen or water, for example, when carbon monoxide, but no oxygen, water, or just a stoichiometric excess thereof is present in the stream to be purified. In some applications, oxygen must be removed from the carbon monoxide, especially if in addition to the formation of carbon dioxide and other disturbing by-products can be formed. For example, in the removal of oxygen and carbon monoxide from copper-containing catalysts from liquid hydrocarbons such as propylene, butene, butadiene or styrene, oxidation products of the hydrocarbon can also be formed (so-called "oxygenates"), which themselves constitute interfering impurities Oxygen can be removed before the removal of carbon monoxide, and carbon monoxide can not be removed by oxidation.

In such cases, carbon monoxide is therefore usually removed by distillation, but so that no CO removal is possible except for residual contents in the ppb range. However, adsorptive processes and adsorbents for purifying material streams are also known. The German Offenlegungsschrift DE 1929977 teaches 20 to 60 parts CuO per 100 parts of ZnO-containing catalysts and their use for the removal of CO from ethylene and propylene streams at a temperature in the range of 50 to 200 ⁰ C. US 3,676,516 teaches a supported Cu catalyst whose copper is present to 20 to 95% as Cu ²⁺ , and its use for CO removal from ethylene or propylene lenströmen at a temperature below about 200 ⁰ C, in the examples concretely at about 93 ⁰ C. US 4,917,711 discloses an adsorbent which contains a copper compound on a high surface area carrier but also adsorbs olefins and therefore only is suitable for the purification of nitrogen, noble gases and saturated hydrocarbons. WO 01/007 383 A1 teaches a process for purifying olefin streams by passing over porous adsorbents such as carbon black or aluminum and / or silicon oxides. JP 02 144 125 A2 (CAS Abstract 113: 177 506) teaches a process for the removal of carbon monoxide and metal carbonyls from exhaust gases produced during semiconductor production by adsorption on manganese oxide and copper oxide-containing adsorption compositions. JP 05 337 363 A2 (CAS Abstract 120: 274 461) discloses adsorbents for removing carbon monoxide, which contain palladium and further oxides on a carrier, the oxides consisting of the oxides of the elements of groups 1 1, 2 and 12 (without Be, Cd, Hg and Ra), 13 (without Al, Tl and the actinides), 14 (without C, Si, Pb and Hf), 5 and 15 (without N, P, As and the "Pa series"), 6 and 16 (without O, S, Se and U), 7 and 8 of the Periodic Table of the Elements.

WO 95/021 146 A1 teaches a process for the removal of carbon monoxide and, if present, also arsine from liquid hydrocarbon streams by contacting with a sorbent, depending on the embodiment of disperse copper in the Oxidati- onstufen 0, +1 or +2, and in certain cases also contains manganese dioxide. EP 537 628 A1 discloses a process for removing carbon monoxide from alpha-olefins and saturated hydrocarbons by contacting them with a catalyst system based on at least one oxide of a metal selected from Cu, Fe, Ni, Co, Pt and Pd and at least one oxide of one from groups 5, 6 or 7 of the Periodic Table of the Elements of selected metal at 0 to 150 ⁰ C. US 4713 090 describes an adsorbent for the recovery of high purity carbon monoxide by pressure or Temperaturwechseladsorption. The adsorbent comprises a composite support having a core of silicon or alumina and an outer layer of activated carbon on which a copper compound is supported.

WO 2004/022 223 A2 teaches a copper, zinc, zirconium and optionally aluminum-containing adsorption composition and their use for the removal of CO from Stoffströ- men in a fully reduced state.

Copper-containing catalysts are also known for applications other than the removal of CO from inert gases or hydrocarbons. No. 4,573,710 and US Pat. No. 4,871,710 disclose Cu / Zn catalysts for desulfurization and de-sizing. WO 95/023 644 A1 teaches a copper catalyst for the hydrogenation of carbon oxides, for example to methanol, or for the so-called shift reaction of carbon monoxide with water to carbon dioxide and hydrogen, in addition to disperse copper and stabilizers such as silica, alumina, chromium oxide, magnesium oxide and / or zinc oxide and optionally also a carrier such as alumina, zirconia, magnesia and / or silica, and its activation and passivation. DE 198 48 595 A1 discloses a catalyst for nitrous oxide decomposition of the general formula M _x AbO ₄ , in which M is Cu or a mixture of Cu and Zn and / or Mg is and may contain further dopants, in particular Zr and / or La. US 5,328,672 teaches an automotive exhaust gas purifying catalyst consisting of a transition metal-containing oxide and a transition metal-containing zeolite, the transition metal being Cu, Co, Ni, Cr, Fe, Mn, Ag, Zn, Ca and "compatible mixtures thereof, preferably in oxide and zeolite, and particularly preferably Cu, and the oxide is selected from La, Ti, Si, Zr oxide and is preferably ZrO.sub.2 EP 804 959 A1 discloses a NO _x decomposition catalyst which, in addition to copper and an MFI zeolite, also comprises SiO 2, Al 2 O 3, SiO 2 / AbO 3, MgO, ZrO 2 and the like, as well as any other elements such as the transition elements Pt, Rh, Cr, Co, Y, Zr, V, Mn, Fe and Zn as well as Ga, In, Sn, Pb, P, Sb, Mg and Ba, may preferably contain P. DE 199 50 325 A1 teaches a spinel monolith catalyst for NOx decomposition with the general formula A _x B (i- _X ) E 2 O 4 in which A is Cu, which may be up to half replaced by Co, Fe, Ni, Mn or Cr; B at least ens is an element selected from Zn, Mg, Ca, Zr, Ce, Sn, Ti, V, Mo and W, and E is Al, which may be replaced in half by Fe, Cr, Ga, La or mixtures thereof.

US Pat. No. 4,552,861 teaches a preparation process for catalysts comprising Cu, Zn, Al and at least one rare earth-zirconium element and their use for methanol synthesis. The methanol catalysts disclosed in US Pat. No. 4,780,481 contain Cu, Zn and at least one alkali metal or alkaline earth metal, noble metals and / or rare earths, it being possible for Zn to be partially replaced by Zr. WO 96/014 280 A1 teaches catalysts which contain Cu, Zn and at least one compound of Al, Zr, Mg, a rare earth metal and / or mixtures thereof and their use for the hydrogenation of carboxylic acid esters. EP 434 062 A1 also teaches a process for the hydrogenation of carboxylic acid esters on a catalyst comprising Cu, Al and a metal selected from the group consisting of Mg, Zn, Ti, Zr, Sn, Ni, Co and their mixtures. No. 4,835,132 describes CO shift catalysts which are produced from a precursor of the formula (Cu + Zn) 6Al _x R _y (CO 3) (x + y) / 2θHi 2 + 2 (x + y) nH 2 O with a layer structure by calcination where R is La, Ce or Zr, x is at least 1 and at most 4, y is at least 0.01 and at most 1.5, and n is about 4.

Methods are also known for activating or reactivating catalysts, including copper-containing ones, or passivating them for transport. Patent DD 0 153 761 relates to a process for the activation or reactivation of iron molybdate redox catalysts, which may also contain copper, wherein the catalysts are first calcined in a non-oxidizing atmosphere and then with an oxidizing

Gas be brought into contact. DE 199 63 441 A1 teaches a process for the regeneration of copper-containing hydrogenation catalysts by first oxidizing and then reducing treatment, wherein the reduction is preferably carried out only in the hydrogenation reactor. WO 02/068 119 A1 discloses copper-containing hydrogenation and dehydrogenation catalysts which are used in a reduced state and passivated for transport by partial oxidation of the copper. EP 296 734 A1 describes copper-containing shift or methanol catalysts obtained by reduction at a temperature below 250 ⁰ C have a Cu surface of at least 70 m ² / g, based on copper. Such activation, regeneration and passivation processes are also known for other catalysts, for example JP 55/003 856 A (WPI Abstract No. WP198013664C) discloses a process for activating palladium-based catalysts by reduction with methanol, oxidation with oxygen, then with acetic acid and oxygen and final reduction with hydrogen. WO 03/002 252 A1 describes an activation process for a cobalt-containing catalyst by treatment with hydrocarbon.

The European patent applications with the file numbers 06101648.1 and

No. 06101654.9 describe copper, zinc and zirconium-containing adsorption compositions in various degrees of reduction and their use for removing carbon monoxide from streams.

However, the increasing demands on the purity of material streams for some applications make new and improved tools and methods for the removal of impurities necessary. Particularly problematic is the removal of carbon monoxide from hydrocarbons, and there especially from typically present in liquid hydrocarbons such as propene, 1- or 2-butene. This invention is therefore based on the object to find an improved adsorbent and an improved process for the adsorptive removal of carbon monoxide from streams.

Accordingly, an adsorption composition comprising copper, zinc and aluminum oxides was found, which is characterized in that the proportion containing its copper has a degree of reduction, expressed as the weight ratio of metallic copper to the sum of metallic copper and copper oxides, calculated as CuO, of at most 60%. Furthermore, processes have been found for removing carbon monoxide from streams which are characterized by the use of the adsorption composition according to the invention as adsorption composition, but alternatively also by their use as catalyst for the reaction of carbon monoxide with oxygen or as a reaction partner of carbon monoxide. In particular, a process has been found for the removal of carbon monoxide from streams by adsorption, which comprises bringing the carbon monoxide-containing stream into contact with an adsorbent mass containing copper, zinc and aluminum oxides characterized as containing copper contains a reduction ratio, expressed as a weight ratio of metallic copper to the sum of metallic copper and copper oxides, calculated as CuO, of at most 60%.

The adsorption composition according to the invention is well suited for use in processes for the purification of streams, in particular for the removal of carbon monoxide (CO) from liquid hydrocarbons such as propylene. A particular advantage of the adsorption composition according to the invention is its extraordinarily high adsorption capacity. It is therefore particularly well suited for liberating streams with a low and constant CO content from CO, without the need for double-sided adsorber systems.

The degree of reduction is a measure of the oxide content of the copper contained in the adsorption composition according to the invention. The degree of reduction is determined as the weight ratio of metallic copper, ie copper in the oxidation state 0 (Cu ⁰ ) to the sum of metallic copper and copper oxides, calculated as CuO, ie copper in the oxidation state +2 (degree of reduction [%] = mass CuO ^■ 100 / (Mass CuO + mass CuO)). Pure metallic copper would have a reduction of 100%, pure CuO would have a 0%. However, a certain degree of reduction does not necessarily mean that the adsorption composition according to the invention contains metallic copper or CuO. A particular degree of reduction can be afforded by any possible combination of corresponding proportions of metallic copper, CuO 2 or CuO. Pure CU2O, ie copper in the oxidation state +1, is formally an equimolar mixture of Cu and CuO and therefore has a degree of reduction of 44.4%. The degree of reduction is determined by any method capable of quantitatively determining copper in its various oxidation states. Particularly simple, however, is the complete oxidation of the copper in a sample of the adsorption by contacting with air at a temperature of at least 250 ⁰ C and at most 500 ⁰ C to constant weight, which should normally be reached after at least 10 minutes and at most 12 hours. The degree of reduction of the sample is calculated from the weight gain of the sample assuming that the added weight is exclusively oxygen and assuming a stoichiometry of the oxidation of

2 Cu + O ₂ -> 2 CuO

calculated.

The degree of reduction of the adsorption composition of the invention is finite, i. different from zero. It is typically at least 1%, preferably at least 5%, and most preferably at least 10%, and generally at most 60%, preferably at most 50%, and most preferably at most 40%. Examples of suitable degrees of reduction are 15%, 20%, 25%, 30%, or 35%, intermediate values are also suitable.

The adsorption composition according to the invention acts by adsorption in the adsorptive process according to the invention. Adsorption refers to the attachment of an adsorbate to the surface of an adsorbent mass ("adsorbent"), generally is reversible by desorption. The adsorbate can also be chemically reacted on the adsorbent, the adsorbent remains chemically substantially unchanged, it is called catalysis (example: the known method for the reaction of CO with oxygen on a metallic copper catalyst to carbon dioxide), the adsorbate is chemically with the Adsorbent to, of absorption (examples: the known method for removing oxygen from gas streams by contacting with metallic copper to form copper (I) oxide and / or copper (II) oxide; or the known method for the removal of carbon monoxide Gas streams by contacting with copper (I) oxide and / or copper (I) oxide to form carbon dioxide and metallic copper). In a pure adsorption as well as in catalysis, the adsorbate or its reaction product is removed by desorption again from the surface, in the absorption is usually a chemical regeneration of the absorbent necessary. In any case, in both catalysis and absorption, the initial step is adsorption, and whether or not an adsorptive purification process ultimately (eg, regeneration of the adsorption mass) results in a catalytic or absorptive step or a purely adsorptive process is involved from the individual case. In the context of the present invention, "adsorptive" means that during the removal of CO from the stream to be purified, no reaction product of the carbon monoxide is released into the stream, and the adsorption composition used remains chemically essentially unchanged, ie its composition is not or only in Whether carbon monoxide or a reaction product thereof is released during the regeneration of the adsorbent according to the invention, ie, catalysis takes place or not, is irrelevant to the invention.

Adsorption or absorption masses are colloquially often referred to as "catalysts" without actually acting catalytically in their intended use.

The adsorption composition according to the invention contains copper, zinc and aluminum oxides. Copper can also be partly present as metallic copper and is otherwise present in the form of Cu (I) and Cu (II) oxides. In pure form, the adsorption composition according to the invention generally contains copper in an amount which, calculated as CuO, is at least 10% by weight, preferably at least 20% by weight and more preferably at least 30% by weight, and generally at most 70% by weight. -%, preferably at most 60 wt .-% and most preferably at most 50% by weight of copper oxide CuO, in each case based on the total amount of the adsorption composition. The adsorption composition according to the invention generally contains in pure form zinc oxide (ZnO) in an amount of at least 10% by weight, preferably at least 20% by weight and more preferably at least 30% by weight and generally at most 70% by weight. , preferably at most 60 wt .-% and more preferably at most 50 wt .-%, each based on the total amount the adsorption mass. It also generally contains in pure form alumina (Al 2 O 3) in an amount of at least 0.1% by weight, preferably at least 5% by weight and more preferably at least 10% by weight and generally at most 50% by weight. %, preferably at most 40 wt .-%, and most preferably at most 30 wt .-%, each based on the total amount of the adsorption. "Pure form" in the context of this invention means that apart from the copper (oxide) zinc oxide and aluminum oxide fractions, no further constituents are present, apart from insignificant constituents which, for example, are still entrained from production, such as residues of starting materials and reagents. Thus, "pure form" means that the adsorption composition consists essentially of the named components.

The percentage amounts of the components of the adsorption mass always add up to 100 wt .-%.

A very suitable adsorption composition is in pure form, for example, from about 40 wt .-% CuO, about 40 wt .-% ZnO and about 20 wt .-% ZrO ₂ , with their shares add up to 100 wt .-%.

The components of the adsorption composition may be in the form of any possible mixed oxide.

The adsorption composition according to the invention can - if desired in individual cases - contain other components, but this is generally not preferred. In particular, the adsorption composition according to the invention and to be used in the process according to the invention preferably contains no zirconium dioxide except for unavoidable impurities, in a particularly preferred form it contains no zirconium dioxide.

The adsorption composition according to the invention may, but does not necessarily have to be in pure form. It is possible to mix them with excipients or apply them to an inert carrier. Suitable inert carriers are the known catalyst carriers such as alumina, silica, zirconia, aluminosilicates, clays, zeolites, kieselguhr and the like.

The adsorption composition according to the invention is prepared as known oxidic catalysts. A convenient and preferred method for producing the adsorption composition according to the invention comprises the following method steps in the order mentioned:

a) preparing a solution or suspension of the components of the adsorption composition and / or starting compounds thereof; b) precipitating a solid from this solution by adding a base, optionally mixing the precipitate with other components of the adsorption composition and / or starting compounds thereof; c) separation and drying of the solid; d) a calcination of the solid; e) deformation of the solid to form bodies; and f) a further calcination of the moldings;

wherein after or simultaneously with step f) step

g) Adjustment of the degree of reduction of the copper-containing fraction of the adsorption composition, expressed as the weight ratio of metallic copper to the sum of metallic copper and copper oxides, calculated as CuO, to a value not exceeding 60%

is carried out.

In the first process step, step a), a solution of the components of the adsorption composition is prepared in a customary manner, for example by dissolving in an acid such as nitric acid. Optionally, instead of the components of the adsorption composition, their starting compounds are also used, for example the nitrates, carbonates, hydroxycarbonates of the metals in an aqueous solution which may also be acidic, for example nitric acid. The quantitative ratio of the salts in the solution is calculated and adjusted stoichiometrically according to the desired final composition of the adsorption composition. It is also possible to add components in insoluble form, for example alumina, as finely divided particles and thus to produce and use a suspension in which some components are dissolved and others are suspended.

From this solution, a solid is precipitated as a precursor of the adsorption in step b). This is done in the usual way, preferably by increasing the pH of the solution by adding a base, such as by adding sodium hydroxide solution or soda solution.

The resulting solid precipitate is usually separated from the supernatant solution prior to drying in step c), such as by filtration or decantation, and washed with water free of soluble constituents such as sodium nitrate. It is also possible to precipitate only some components of the adsorbent mass or their precursors in this way and to mix the solid precipitate with other, for example, insoluble components such as alumina. It is basically possible to do this by mixing dried powders, but preferably the mixing takes place as a suspension before separation and drying of the precipitate. The precipitate (optionally mixed with other insoluble components) is then normally dried before further processing by conventional drying methods. In general, this is sufficient temperature treatment at slightly elevated tempera-, such as at least 80 ⁰ C, preferably at least 100 ⁰ C and most preferably at least 120 ⁰ C., for a period of 10 minutes to 12 hours, preferably 20 minutes to 6 Hours, and more preferably 30 minutes to 2 hours. It is also possible and particularly convenient to directly convert the product of the precipitation - some alkali, for example, sodium content of the adsorption mass, generally - or, after washing by spray drying, to a dry, further processable powder.

After drying, the precipitated and dried precursor of the adsorption composition is optionally subjected to the calcination step d). The calcination temperature used here is in general at least 350 ⁰ C, preferably at least 400 ⁰ C and most preferably at least 450 ⁰ C, and generally not more than 650 ⁰ C, preferably at most 600 ⁰ C and in a particularly preferred manner at most 550 ^° C. An example of a suitable temperature window for this calcination is the range of 470 to 530 ^° C., ie 500 ± 30 ^° C. The calcination time is generally at least 5 minutes, preferably at least 10 minutes, and most preferably at least 20 Minutes, and generally at most 6 hours, preferably at most 2 hours, and most preferably at most 1 hour. An example of a suitable range of residence time for this calcination step is the range of 20 to 30 minutes. The drying step c) and the calcination step d) can merge directly into each other.

After the drying step c) or the calcination step d), the adsorption composition or its precursor in the shaping step e) by conventional shaping procedures such as Verstrangen, tableting or pelletizing into shaped articles such as stranded or extrudates, tablets or - even spherical - pellets processed.

After the shaping step, the adsorption mass (ie, its precursor, in fact) is subjected to a calcination step f). The here applied Kalzinati- onstemperatur lies generally at least 300 ⁰ C, preferably at least 350 ⁰ C and most preferably at least 400 ⁰ C, in particular at least 450 ⁰ C and generally not more than 700 ⁰ C, preferably at most 650 ⁰ C and most preferably at most 600 ⁰ C, especially at most 580 ⁰ C. An example of a suitable temperature window for this calcination step is the range of 490 to 550 ⁰ C, in particular the range of 500 to 540 ⁰ C. The calcination is generally at least 30 minutes, preferably at least 60 minutes, and generally at most 10 Hours, preferably at most 3 hours, and more preferably at most 2 hours, in particular at most 90 minutes. In a particularly preferred embodiment, the temperature in the said region is slowly increased over the calcination time.

During the calcination steps, the adsorption mass precursor is converted into the actual adsorption composition and, as usual, the BET surface area and the pore volume of the adsorption composition are adjusted. As is known, the BET surface area and the pore volume decrease with increasing calcination time and calcination temperature.

Preferably, at least a total of so long calcined that the content of the adsorption of carbonate (calculated as CO3 ^{2 "} ) at most 10 wt .-%, based on the total weight of the calcination, and their BET surface area in the range of at least 10 m ² / g, preferably at least 30 m ² / g and in a particularly preferred form at least 40 m ² / g, in particular at least 50 m ² / g and generally at most 100 m ² / g, preferably at most 90 m ² / g and in particular preferably not more than 80 m ² / g, in particular at most 75 m ² / g. the pore volume of the adsorption, measured as absorption of water, is adjusted during the calcination at a value of at least 0.05 ml / g. These values are for the inventive Adsorption preferred.

The adsorption composition according to the invention can also be deposited on a carrier as mentioned above. This is done by conventional impregnation or precipitation processes. A patterning method is known to be a precipitation method in the presence of a support or a carrier precursor. In order to carry out an application process, a carrier or carrier precursor is preferably added to the solution prepared in step a) in the precipitation process described above. If the carrier is already present in the form of preformed finished moldings, ie a pure impregnation process eliminates the shaping step e), otherwise the carrier in the course of processing of the precursor of the adsorbent by precipitation, drying, calcination and shaping is formed.

In the preparation of the adsorption composition, it is of course possible to use known auxiliary substances, such as, for example, calcination-decomposing pore formers or tabletting aids.

The adjustment of the degree of reduction can be made by setting appropriate process conditions in the calcination (especially calcination under copper not fully oxidizing atmosphere) or in a separate process step after calcination, in the latter case, the adjustment of the degree of reduction must not necessarily take place immediately after calcination , The setting of the Degree of reduction is carried out by any known method suitable for changing the degree of oxidation of copper. If copper is present predominantly in reduced form, it is reacted with oxygen, copper is present predominantly as copper oxide, with hydrogen.

Most calcination is carried out under air, copper is therefore present in the form of CuO in the obtained after calcination precursor of the adsorption composition according to the invention. The degree of reduction is then adjusted by reduction of the copper to the desired degree of reduction. This is done by treating the precursor present after calcination with a reducing agent. Any known reducing agent that can reduce copper can be used. The precise reduction conditions to be used depend on the precursor and its composition as well as the reducing agent used and can be easily determined in a few routine experiments. A preferred method is the treatment of the precursor with hydrogen, usually by passing a hydrogen-containing gas, preferably a hydrogen / nitrogen mixture at elevated temperature.

It is also possible first to completely reduce the precursor of the adsorption composition according to the invention and then to oxidize to the desired degree of reduction. The complete reduction of the precursor of the adsorption composition is achieved by reducing the copper contained in the adsorption composition to copper metal. In principle, this can be done by any reducing agent which can reduce copper from the oxidation stages I or II to the oxidation state O. This can be done with liquid or dissolved reducing agents, in which case it must be dried after the reduction. Much more convenient therefore is the reduction with a gaseous reducing agent, especially the reduction with hydrogen by passing a hydrogen-containing gas. The temperature to be used in this case is generally at least 80 ^° C., preferably at least 100 ^° C., and more preferably at least 120 ^° C., and generally at most 180 ^° C., preferably at most 160 ^° C., and most preferably at most 140 ^° C. A suitable temperature is for example about 130 ^° C. The reduction is exothermic. The amount of reducing agent supplied must be adjusted so that the selected temperature window is not left. The course of the activation can be followed by the temperature measured in the adsorbent bed ("temperature programmed reduction, TPR").

A preferred method for reducing the precursor of the adsorption composition is to adjust the desired reduction temperature following a drying carried out under a stream of nitrogen and to add a small amount of hydrogen to the nitrogen stream. A suitable gas mixture initially contains, for example, at least 0.1% by volume of hydrogen in nitrogen, preferably at least 0.5% by volume and more preferably at least 1% by volume, and at most 10% by volume, preferably at most 8% by volume and most preferably at most 5% by volume. A suitable value is, for example, 2% by volume. This initial concentration is either maintained or increased to reach and maintain the desired temperature window. The reduction is complete when, despite the constant or increasing level of the reducing agent, the temperature in the bulk of the mass decreases. A typical reduction time is generally at least 1 hour, preferably at least 10 hours and more preferably at least 15 hours, and generally at most 100 hours, preferably at most 50 hours, and most preferably at most 30 hours.

The drying of the precursor of the adsorption composition, if necessary, is carried out by heating the precursor to a temperature of generally at least 100 ^° C., preferably at least 150 ^° C., more preferably at least 180 ^° C., and generally at most 300 ^° C., preferably at most 250 ⁰ C and most preferably reaches at most 220 ⁰ C. A suitable drying temperature is, for example, about 200 ^° C. The precursor is kept at the drying temperature until no more disturbing residues of adhering moisture are present; this is generally the case for a drying time of at least 10 minutes, preferably at least 30 minutes, and more preferably at least 1 hour, and generally at most 100 hours, preferably at most 10 hours and most preferably at most 4 hours. Preferably, the drying takes place in a gas stream in order to remove the moisture from the bed. Dry air can be used for this purpose, for example, but it is particularly preferred to flow the bed with an inert gas; nitrogen or argon are particularly suitable here.

After complete reduction, the degree of reduction by oxidation of the adsorption mass precursor is adjusted to the desired value. This can be done by any known oxidizing agent that can oxidize copper. Conveniently, oxygen is used, in particular air or an oxygen / nitrogen or air / nitrogen mixture ("lean air"). [. Eine] A preferred method for oxidizing the precursor of the adsorption composition is to shut off the hydrogen supply after the reduction, with the residual hydrogen present Nitrogen must be rinsed out of the reaction vessel, then adjusted to the desired oxidation temperature and the nitrogen flow is mixed with a small amount of oxygen Temperature, total gas oxygen content and treatment time must be optimized by routine experiments with determination of the degree of reduction for each individual case. 2 vol.% Oxygen in nitrogen, preferably at least 0.3 vol.% And more preferably at least 0.4 vol.%, And at most 1.0 vol.%, Preferably at most 0.9 vol. % and most preferably not more than 0.8% by volume rt is for example, 0.6 vol .-%. A typical oxidation time is generally at least 15 minutes, preferably at least 30 minutes, more preferably at least 45 minutes, and generally at most 2 hours, preferably at most 90 minutes, and most preferably at most 75 minutes. For example, it is oxidized for one hour. The amount of gas to be used is typically generally at least 1500 Nl of gas per liter of adsorbent mass precursor and hour (Nl = standard liters, ie based on 0 ^° C and atmospheric pressure), preferably at least 2,000 Nl / l ^* h and most preferably at least 2,300 Nl / L ^* h and generally not more than 4 000 Nl / l ^* h, preferably not more than 3 500 Nl / l ^* h and more preferably not more than 3 200 l / lh. For example, 2 500 Nl / l ^* h are well suited. The set temperature is generally at least 0 ⁰ C, preferably at least 10 ⁰ C and in a particularly preferred form at least 20 ⁰ C and generally at most 60 ⁰ C, preferably at most 50 ⁰ C and in a particularly preferred form at most 40 ⁰ C. For example Room temperature well suited.

The Adsorptionsmassen-shaped bodies are filled for their use in a usually called "adsorber", sometimes called "reactor" container in which they are brought into contact with the stream to be purified.

The finished adsorption composition is preferably dried before use for the adsorption of CO (optionally again) to remove traces of adhering moisture and to increase the adsorption capacity. The drying of the finished adsorption composition is carried out in the same way as the drying of its precursor described above.

Conveniently, the setting of the degree of reduction and the drying in the adsorber is carried out, since otherwise a great deal of effort is required to protect the ready-to-use activated adsorption when filling in the adsorber from air and moisture.

Following the adjustment of the degree of reduction and any drying carried out before or after the setting of the degree of reduction, the adsorption composition according to the invention is ready for use.

The adsorptive process according to the invention is a process for the removal of carbon monoxide from streams by adsorption, which comprises contacting the carbon monoxide-containing stream with an adsorption compound which contains copper, zinc and aluminum oxides and which in turn is characterized is that the copper-containing portion thereof has a degree of reduction in terms of weight ratio of metallic copper to the sum of metallic copper and copper oxides, calculated as CuO, of at most 60%. The adsorptive process according to the invention is thus achieved by the use of the invention. characterized according to the invention adsorption. An advantage of the adsorptive process according to the invention is its applicability to material flows which are either oxygen-free, at a temperature which is insufficient for the customary catalytic conversion of carbon monoxide with oxygen to carbon dioxide, or interfere with the further use of carbon dioxide or oxygenates.

In principle, with the adsorptive process according to the invention, each material stream can be freed of contaminants by carbon monoxide, for example inert gas streams (nitrogen, helium, neon, krypton, xenon and / or argon) or hydrocarbon streams, for example alkanes (methane, ethane, propane, butane, their mixtures, isomers and isomer mixtures) or alkenes (also called "olefins") such as ethene, propene, 1-butene, 2-butene, 1, 3-butadiene and / or styrene.

It is also possible to use the adsorption composition according to the invention in a non-adsorptive manner for the removal of carbon monoxide. This is particularly advantageous if the stream to be liberated from carbon monoxide also contains oxygen in addition to carbon monoxide, is present at a sufficiently high temperature for the catalytic conversion of oxygen with carbon monoxide, and does not interfere with its further use of carbon dioxide or oxygenates. Thus, carbon monoxide from carbon monoxide and oxygen-containing material streams can be converted to carbon dioxide by catalytic conversion of carbon monoxide with oxygen on the adsorption composition used as catalyst according to the invention and thus removed from the material stream. Likewise, carbon monoxide can be removed from carbon monoxide-containing material streams by reacting carbon monoxide with a copper (I) and / or copper (II) oxide-containing adsorption composition according to the invention to form metallic copper to form carbon dioxide from the material stream. It is equally possible to remove oxygen from streams by absorption on the metallic copper-containing adsorption composition of the invention to form copper (I) oxide and / or copper (II) oxide, or in the presence of hydrogen by copper-catalyzed formation of water. As with other copper-containing compositions can also adsorbent with the invention not only carbon monoxide, oxygen and the latter also hydrogen, but also other with copper or copper oxide-reactive impurities such as elemental mercury and / or mercury, sulfur, antimony and / or arsenic-containing compounds be removed from streams. In other words, the adsorption composition according to the invention can be used in all known processes in which copper-containing solids are used catalytically, absorptively or as reactants.

The adsorptive process according to the invention is preferably used for removing carbon monoxide from alkene streams, in particular for removing carbon monoxide from alkene streams, which are usually in liquid form. Liquid present In addition to the use of unusually high pressures, typical alkenes typically do not have the temperature necessary for the catalytic removal of carbon monoxide by reaction with oxygen, and in the subsequent use for the polymerization, oxygenation would be disturbed.

The adsorptive process according to the invention is particularly suitable for removing carbon monoxide from propene, 1-butene, 2-butene, 1,3-butadiene, butene mixtures, butene / butadiene mixtures or styrene in order to reduce the carbon monoxide content to that for "polymer grade". In a very particularly preferred embodiment, carbon monoxide is removed by adsorption from liquid propene with the process according to the invention.

The adsorptive process according to the invention makes it possible to remove carbon monoxide from streams. It is particularly suitable for the removal of carbon monoxide from streams which is generally at least 0.001 ppm (for gases VoIppm, for liquids, ppm by weight), preferably at least 0.01 ppm, and generally at most 1000 ppm, preferably at most 100 ppm, and most preferably at most 10 ppm carbon monoxide. For relatively high initial concentrations of carbon monoxide, it is usually more economical, beforehand, another known purification method such as distillation, catalytic oxidation of carbon monoxide with oxygen to carbon dioxide or oxidation of carbon monoxide with copper oxide to form metallic copper and carbon dioxide, optionally with subsequent separation of Carbon dioxide and oxygenates perform, otherwise the adsorption capacity of the adsorption can be achieved too quickly.

In order to carry out the adsorptive process according to the invention, the stream of carbon monoxide to be liberated in the adsorber is passed over the bed of the adsorption mass molding according to the invention.

The temperature is not or only slightly critical for the adsorptive process of the invention from a technical point of view. Typical temperatures are in the range of at least -270 ⁰ C, preferably at least -100 ⁰ C and particularly preferably at -40 ⁰ C, and a maximum of 300 ⁰ C, preferably not exceeding 200 ⁰ C and in a particularly preferred manner at most 100 ⁰ C. Conveniently, the temperature is not influenced separately, but worked at the temperature that has to be treated material flow.

The essential parameter with which the degree of depletion is determined, besides the conveniently not particularly influenced temperature as described, is the contact time between mass flow and adsorption mass. This contact time is determined by the velocity of the stream and the volume of the adsorbent mass bed. Most of the volume flow of the material stream to be purified is through the Ka capacity of upstream or downstream equipment. Furthermore, the adsorption capacity of the adsorption composition is limited, so that a certain amount of adsorption composition can be used only for a certain period of time for the process according to the invention before it has to be regenerated. Although this makes it initially desirable to use the largest possible amount of adsorption compound, this is counteracted by the increasing costs associated with adsorber size. The amount of adsorption in the adsorber is therefore chosen in each case so that on the one hand the desired degree of depletion and on the other hand a tolerable short operating time of an adsorber between two regenerations of the adsorption is achieved. Advantageously, at least two adsorbers are provided, of which at least one can be acted upon with to be purified material flow, while the adsorption mass is regenerated in at least one other. This is a routine optimization task for a person skilled in the art.

Depending on the chosen adsorber size, the maximum absorption capacity of carbon monoxide adsorption mass contained therein is sooner or later reached, so that it must be regenerated.

For regeneration of the adsorption of the invention, the stream to be purified is first turned off, preferably it is passed into a parallel, filled with fresh or regenerated adsorbent adsorbent.

The adsorption mass to be regenerated is then regenerated. This is done by desorption. It is irrelevant whether, before the desorption, the adsorbed carbon monoxide reacts catalytically with possibly adsorbed oxygen or purely chemically by reaction with copper oxide present in the adsorption mass to carbon dioxide or in another way, for example with any hydrogen present, to methanol or methane, and these Desorbed reaction products, essential is the restoration of the adsorption capacity of the adsorption.

The desorption is carried out by passing a fluid, preferably a gas, by raising the temperature or by a combination of these measures. In a preferred manner, the adsorber is flowed through with the adsorptive mass to be regenerated with a gas and heated in the process. The gas may be inert, such as nitrogen, methane or argon, but it is also possible to use hydrogen, in which case the CO is converted to methanol or methane. The desorption temperature is generally set to a value of at least 50 ^° C., preferably at least 100 ^° C., and more preferably at least 150 ^° C., and generally at most 500 ^° C., preferably at most 450 ^° C., and more preferably at most 400 ^° C. set. For example, a desorption temperature of about 300 ⁰ C is suitable. The duration of the regeneration is typically usually at least 1 hour, preferably at least 10 hours and more preferably at least 15 hours, and generally at most 100 hours, preferably at most 50 hours, and most preferably at most 30 hours.

In order to replace oxygen lost from the copper, it is often advantageous to carry out the desorption with an inert gas, preferably nitrogen or argon, which contains trace amounts of oxygen. Conveniently, nitrogen is used for desorption, which generally comprises oxygen in an amount of at least 1 ppm, preferably at least 5 ppm and more preferably at least 10 ppm, and generally at most 300 ppm, preferably at most 250 ppm, and most preferably at most Contains 200 ppm.

The actual desorption can also be initiated with the removal of remaining material stream to be purified from the adsorber by rinsing the adsorber, expediently with the gas stream used for desorption at normal temperature.

Following this regeneration, the adsorbent mass is generally ready for reuse immediately. In individual cases - especially if the desired degree of reduction has changed too much - it may be advisable or necessary to subject the adsorption mass to a renewed adjustment of the degree of reduction.

With the adsorption composition according to the invention and the adsorptive process according to the invention, it is possible to remove carbon monoxide from material streams in a simple and economical manner. The thus purified material streams can then be used as intended.

Examples

Example 1 (comparison): Preparation of an adsorption composition with a degree of reduction of 0%

In a heatable and equipped with a stirrer precipitation vessel 8.1 l of water and 672 g of boehmite be (PURAL ^® SB of Condea Chemie GmbH of Hamburg, Al ₂ ₃ content wt .-% around 72 O) and heated at 50 ⁰ C presented. In the course of half an hour, 7.5 l of aqueous solution of 2980 g of Cu (NOs) ₂ × 3 H ₂ O and 3560 g of Zn (NOs) ₂ × 6 H ₂ O were metered in with stirring. At the same time, a 20% strength by weight sodium carbonate solution was metered in so that a pH of 6.2 was maintained in the precipitation vessel. In total, 13.8 kg of the sodium carbonate solution were consumed. The resulting suspension was filtered off and washed with water nitrate-free (<25 ppm nitrate in the effluent). The filter cake was dried at 120 ⁰ C and then calcined at 500 ⁰ C over 25 minutes. 1.7 kg of the material thus obtained were intensively mixed with 300 g of ammonium nitrate as pore-forming agent and 60 g of graphite as tabletting aid and shaped into 3 × 3 mm tablets. These tablets were calcined at 520 ^° C. for 75 minutes.

Examples 2 and 3 and Comparative Examples 4 and 5

Samples of the tablets obtained in Example 1 were reduced by passing a gas mixture of 25 vol .-% hydrogen in nitrogen at 180 ⁰ C in a tubular reactor. The reduction periods and set reduction rates are given in the table.

Samples of the tablets obtained in (Comparative) Examples 1 to 5 were at 100 ⁰ C and ambient pressure (ie, only necessary for the flow of the bed pressure is applied before the reactor) in a tubular reactor (adsorber) with a gas mixture of 750 ppm CO applied in ethylene, with a GHSV of 2300 h ^'1. the concentration of CO in the exhaust gas is measured continuously and the "determined breakthrough point", ie the ratio of the current supplied to the adsorption volume of CO (calculated as pure substance) per volume of the adsorption [I CO / I adsorption mass], in which 5% of the CO concentration of the gas mixture fed to the adsorber are measured after passing through the adsorber. This breakthrough point is therefore a measure of the adsorption capacity of the adsorption.

The values achieved are listed in the following table.

The examples show that the adsorption composition according to the invention has a considerably increased adsorption capacity for carbon monoxide compared with previously known or not according to the invention.

Claims

claims

1. Copper, zinc and aluminum oxide-containing adsorption composition, characterized in that the copper-containing fraction has a degree of reduction, expressed as the weight ratio of metallic copper to the sum of metallic copper and copper oxides, calculated as CuO, of at most 60%.

2. Adsorption composition according to claim 1, the copper in an amount of 30 to

99.8% by weight of CuO, zinc in an amount containing from 0.1 to 69.9% by weight of ZnO and zirconium in an amount corresponding to from 0.1 to 69.9% by weight of ZrO2, in each case based on the total amount of the adsorption, wherein the proportions of the individual components add up to 100 wt .-%.

3. An adsorption composition according to claim 2, which consists essentially of copper in an amount of 30 to 99.8 wt .-% CuO, zinc in an amount containing 0.1 to 69.9 wt .-% ZnO and zirconium in a Amount corresponding to 0.1 to 69.9 wt .-% ZrÜ2 consists, in each case based on the total amount of the adsorption, wherein the proportions of the individual components add up to 100 wt .-%.

4. Adsorption composition according to one of claims 1, 2, or 3 on an inert carrier.

5. Adsorption composition according to one of claims 1 to 4, characterized in that zinc in the form of zinc oxide (ZnO) and aluminum in the form of aluminum oxide (Al2O3) are present.

6. A process for the removal of carbon monoxide from carbon monoxide-containing streams by adsorption on an adsorption, characterized in that one brings the carbon monoxide-containing stream with a defined in the claims 1 to 5 adsorption in contact.

7. The method according to claim 6, characterized in that one removes carbon monoxide from a liquid propylene stream.

8. A process for the removal of carbon monoxide from carbon monoxide and oxygen-containing streams by catalytic conversion of carbon monoxide with oxygen to carbon dioxide, characterized in that one uses the defined in claims 1 to 5 adsorbent as a catalyst.

9. A process for removing carbon monoxide from carbon monoxide-containing streams by reacting carbon monoxide with a copper (I) - and / or copper (II) oxide-containing solid to carbon dioxide to form metallic copper, characterized in that the in the claims chen 1 to 5 defined adsorption as a copper (l) - and / or copper (II) oxide containing solids used.

10. A process for the preparation of the adsorption composition as defined in claims 1 to 5, comprising the following process steps in the said order:

a) preparing a solution or suspension of the components of the adsorption composition and / or starting compounds thereof; b) precipitating a solid from this solution by adding a base, optionally with mixing of the precipitate with other components of the

Adsorptionsmasse and / or of starting compounds thereof; c) separation and drying of the resulting solid; d) calcination of the solid; e) deformation of the solid to form bodies; f) a further calcination of the moldings;

characterized in that it comprises a method step to be carried out after or simultaneously with method step f)

includes.

1 1. A process for the regeneration of the adsorption composition defined in claims 1 to 5 after their use for adsorptive removal of carbon monoxide from carbon monoxide-containing material streams, characterized in that the adsorption composition to a temperature in the range of 50 to

500 ⁰ C heated and / or flows through a bed of the adsorption mass to be regenerated with a gas.