Catalyst based on zeolite and ALPO structure and having high macropore volume

Abstract

The invention relates to a catalyst comprising a zeolite having at least one series of channels whose opening is at least equal to 10 oxygen atoms (10MR) and a binder, in which:-the catalyst comprises phosphorus and comprises an AlPO structure determined by a signal between 35 and 45 ppm in a spectrum obtained by the 27Al NMR analysis of the catalyst; -the pore volume (V (4-900)) of the pores of the catalyst having a size of 3.6 to 900 nm is greater than or equal to 0.25 ml / g; and-the catalyst has a pore volume (V (30-310)) of pores having a size of 30 to 310 nm of less than or equal to 0.080 ml / g. The invention also relates to the use of said catalyst in a process for the dehydration of alcohols and to a process for the preparation of ethylene from a feedstock comprising ethanol using said catalyst.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a catalyst which comprises at least partially zeolite having an AlPO structure, a binder and phosphorus advantageously, and exhibits a large pore volume. The present invention also relates to a method for preparing such a catalyst. Such a catalyst has great advantages for industrial processes involving the presence of steam at high temperatures, such as the dehydration of alcohols to obtain the corresponding olefins, such as the dehydration of ethanol to selectively prepare ethylene. The present invention also relates to the use of the catalyst according to the present invention in a method for dehydrating alcohols, such as the dehydration of ethanol to obtain ethylene. PRIOR ART

[0002] The use of an effective catalyst is one of the keys to obtaining a viable industrial process. More particularly, the dehydration of alcohols in the presence of a catalyst to prepare olefins has been well described in the literature. The reference catalyst commonly used is an acidic monofunctional catalyst. Gamma-alumina is one of the most frequently mentioned catalysts for conversion in the literature (see H. and R. “The Dehydration of Alcohols over Alumina.I:The Reaction Scheme”,Journal of Catalysis(1966),5,264-270). Zeolites are also used for this application, and in particular ZSM-5 since the 1980s (see S.N.Chaudhuri et al.,“Reactions of Ethanol over ZSM-5”,Journalof Molecular Catalysis,62,289-295(1990)). For example, Patent FR 2 978 145 particularly describes a method for preparing ethylene from an ethanol feedstock in the presence of a dehydration catalyst comprising ZSM-5 zeolite treated with H3PO4 (such that the P2O5 content is 3.5 wt%).

[0003] Application WO 2013 / 017499 discloses a method for manufacturing a phosphorus-modified zeolite. The method includes a stage of treating a zeolite containing at least one ten-membered ring in its structure with steam at a high temperature (steaming), followed by introducing phosphorus, then shaping the modified zeolite with a binder and depositing a metal, and finally a new treatment with steam (or steaming). Application WO 2013 / 017497 itself also discloses a method for manufacturing a phosphorus-modified zeolite. The method described in Application WO 2013 / 017497 itself includes shaping a zeolite containing at least one ten-membered ring in its structure with a binder, a stage of treating the zeolite with steam at a high temperature (steaming) before or after shaping, then introducing phosphorus and a metal element, and finally a new treatment with steam (or steaming). Similarly, document WO 2013 / 017496 describes the use of a catalyst containing a phosphorus-modified zeolite for converting at least one alcohol into an olefin having the same number of carbon atoms as the alcohol in a dehydration process, wherein the catalyst is manufactured by a method comprising the steps of: shaping a zeolite containing at least one ten-membered ring in its structure with a binder, a stage of treating the zeolite with steam at a high temperature, then introducing phosphorus and a metal element, and finally a new treatment with steam. Application WO 2013 / 017498 discloses a catalyst containing a phosphorus-modified zeolite and a binder, wherein the phosphorus-modified zeolite portion has an AlPO structure and contains at least one ten-membered ring in its structure, and the AlPO structure is determined by a signal at 35 - 45 ppm in the 27 Al NMR spectrum.

[0004] Document EP 511 013 provides a method for preparing C2 - C5 olefins from heavier olefinic and / or paraffinic compounds by contacting them with a specific ZSM-5-based catalyst at a high temperature, a high space velocity, and a low hydrocarbon partial pressure. The catalyst is treated with steam before being used for hydrocarbon conversion and contains 1 wt% to 50 wt% of a phosphorus-containing ZSM-5 zeolite having a surface Si / Al ratio of 20 to 60 (0.1 wt% - 10 wt% of phosphorus relative to the weight of the catalyst). No metal such as Ca is introduced into the catalyst.

[0005] Document US2006 / 106270 relates to the use of a catalytic system in hydrocarbon synthesis for converting an oxygenate into propylene at a high temperature. The catalytic system comprises a molecular sieve dispersed in a phosphorus-modified alumina matrix containing labile phosphorus and / or aluminum anions, which enable hydrothermal stabilization of the catalytic system.

[0006] Document WO 2009 / 098262 itself also discloses a catalyst for the dehydration of ethanol to obtain ethylene. The catalyst comprises ZSM-5 zeolite treated with steam and modified with phosphorus and a binder.

[0007] AlPO aluminophosphate materials are known in the prior art. They exist in different Al / P atomic ratios and exhibit acidic properties at an Al / P atomic ratio > 1, and even more significantly in the form of hydrogen phosphates with Al / P < 1. These are known to be used as acid catalysts in the dehydration of alcohols, especially methanol (see US 5 753 716). In the prior art, the aluminum source for manufacturing AlPO aluminophosphate is generally prepared by treating an external aluminum source (aluminum oxide or aluminum salt) with a phosphorus source, followed by mixing with zeolite to prepare a catalyst. It is also possible for different types of aluminum oxide or aluminum salt to be mixed with phosphorus and zeolite simultaneously.

[0008] One object of the present invention is to provide a novel zeolite-based catalyst for the dehydration of ethanol to obtain ethylene, such that high ethanol conversion and high ethylene selectivity can be achieved by limiting the formation of unwanted products (oligomers and oxygenates), while exhibiting satisfactory hydrothermal tolerance. Summary of the Invention

[0010] The present invention relates to a catalyst comprising a zeolite and a binder, the zeolite exhibiting at least a series of channels with openings of at least 10 oxygen atoms (10MR), wherein:

[0011] - the catalyst comprises phosphorus and comprises an AlPO structure, which is determined by a signal between 35 and 45 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst;

[0012] - the pore volume (V (4-900) ) of the pores of the catalyst with a size of 3.6 to 900 nm is greater than or equal to 0.254 ml / g;

[0013] - the pore volume (V (30-310) ) of the pores of the catalyst with a size of 30 to 310 nm is less than or equal to 0.080 ml / g.

[0014] Surprisingly, the inventors have found that such a catalyst according to the invention, which exhibits a specific composition and specific texture characteristics (porosity), enables improved performance qualities to be obtained in the reaction of alcohol dehydration to obtain the corresponding olefin having the same number of carbon atoms, in particular in the reaction of ethanol dehydration to obtain ethylene, while exhibiting satisfactory mechanical strength. In particular, such a catalyst enables high selectivity for the target olefin, more particularly for ethylene, to be achieved in the method for dehydrating said alcohol, while ensuring high conversion of the alcohol, particularly ethanol, and an optimum yield of the target olefin. In addition, such a catalyst exhibits entirely suitable mechanical properties, in other words, mechanical properties sufficient to enable handling and use on an industrial type unit. In particular, the catalyst according to the invention exhibits an SPCS value (single pellet crush strength) of greater than or equal to 0.7 daN / mm, preferably greater than or equal to 0.8 daN / mm.

[0015] According to a second aspect, the invention also relates to the use of a catalyst according to the invention in a method for dehydrating an alcohol to obtain an olefin having the same number of carbon atoms, in particular in a method for dehydrating ethanol to obtain ethylene.

[0016] According to a third aspect, the invention also relates to a method for preparing ethylene from a feedstock containing ethanol, said method comprising a stage of ethanol dehydration carried out in the presence of a catalyst as described above, at an inlet temperature of from 250 °C to 550 °C, at an inlet pressure of from 0.1 to 1.7 MPa and at a weight hourly space velocity of from 0.1 to 30 h -1 -1.

[0017] Description of embodiments

[0018] Advantageously, the mechanical properties can be determined by the single pellet crush strength (SPCS) test described by the ASTM D 6175-3 method. The ASTM D 6175-3 method consists of measuring the breaking strength of each particle in a representative sample containing at least 50 particles. The results are weighted by the length of the extrudate. The SPCS value is the average of the breaking strengths measured for all the particles of the sample and expressed per unit length of the extrudate (in daN.mm -1 -1).

[0019] According to the invention, the expression “... to... / between... and...” means that the limiting values of the interval are included within the said range of values. If this were not the case and if the limiting values were not included within the said range, the invention would provide such details.

[0020] In this specification, the expression "greater than..." is understood as strictly greater than and is represented by the symbol ">", and the expression "less than" is understood as strictly less than and is represented by the symbol "<". When the limits are included, this information will be provided by the corresponding expressions "greater than or equal to..." (and corresponding to the symbol "≥") and "less than or equal to" (corresponding to the symbol "≤").

[0021] Within the meaning of the present invention, different parameter ranges can be used alone or in combination. For example, within the meaning of the present invention, a range of preferred values of the zeolite structure can be combined with a range of more preferred values of the pore volume.

[0022] Subsequently, specific embodiments of the present invention are described. They can be used alone or in combination, without restricting the combination when this is technically feasible.

[0023] The present invention relates to a catalyst comprising a zeolite and a binder, preferably a siliceous binder or clay, the zeolite exhibiting at least a series of channels with openings of at least 10 oxygen atoms (10MR), preferably zeolites of the MFI, MTT, FER, MEL, TON, MWW, EUO, and MFS structures, preferably zeolites of the MFI structure and in a preferred manner ZSM-5, wherein:

[0024] - The catalyst contains phosphorus and contains an AlPO structure, and the content of the AlPO structure in the catalyst preferably accounts for 15% to 40%, preferably 20% to 35%, and in a preferred manner 25% to 34% of the aluminum-containing entities of the catalyst. The presence and quantification of the AlPO structure in the catalyst are determined by a signal measured between 35 and 45 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst, and in particular, the content of the AlPO structure corresponds to the ratio of the surface area of the signal at 35 - 45 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst to the total surface area of the signals between -50 and 100 ppm;

[0025] - The pore volume (V (4-900) ) of the pores of the catalyst with a size of 3.6 to 900 nm is greater than or equal to 0.25 ml / g, preferably greater than or equal to 0.250 ml / g, preferably greater than or equal to 0.26 ml / g, actually even greater than or equal to 0.260 ml / g, and preferably less than or equal to 1.00 ml / g, preferably less than or equal to 0.80 ml / g, actually even less than or equal to 0.60 ml / g;

[0026] - The pore volume (V (30-310)) is less than or equal to 0.080 ml / g, preferably less than or equal to 0.070 ml / g;

[0027] - Advantageously, relative to the total weight of the catalyst, the zeolite content of the catalyst is 5.0 wt% to 95.0 wt%, preferably 15.0 wt% to 95.0 wt%, preferably 50.0 wt% to 90.0 wt%, and preferably 65.0 wt% to 85.0 wt% in a preferred manner;

[0028] - Advantageously, relative to the total weight of the catalyst, the phosphorus element content of the catalyst is 0.5 wt% to 20.0 wt%, preferably 0.5 wt% to 10.0 wt%, preferably 1.0 wt% to 5.0 wt%, and preferably 2.0 wt% to 4.0 wt% in a preferred manner;

[0029] - Advantageously, the catalyst contains a metal, preferably in the form of a metal oxide, and the metal is preferably an alkaline earth metal or a rare earth metal, preferably selected from magnesium, calcium, strontium, barium, lanthanum, and cerium.

[0030] According to the present invention, the catalyst contains a zeolite and a binder, and the zeolite exhibits at least a series of channels with openings at least equal to, preferably equal to, 10 oxygen atoms (10MR). Very advantageously, relative to the total weight of the catalyst, the zeolite content of the catalyst is 5.0 wt% to 95.0 wt%, preferably 15.0 wt% to 95.0 wt%, preferably 50.0 wt% to 90.0 wt%, and preferably 65.0 wt% to 85.0 wt% in a preferred manner. Relative to the total weight of the catalyst, the binder content of the catalyst is advantageously 5.0 wt% to 95.0 wt%, preferably 5.0 wt% to 85.0 wt%, preferably 10.0 wt% to 50.0 wt%, and preferably 15.0 wt% to 35.0 wt% in a preferred manner.

[0031] Advantageously, the zeolite of the catalyst according to the present invention, which exhibits at least a series of channels with openings at least equal to, preferably equal to, 10 oxygen atoms (10MR), is a crystalline silicate that exhibits at least a series of channels with openings at least equal to, preferably equal to, 10 oxygen atoms (10MR), and is preferably selected from zeolites of MFI, MTT, FER, MEL, TON, MWW, EUO, and MFS structures. The zeolite is very preferably an MFI-type zeolite, and preferably a ZSM-5 zeolite in a preferred manner. In a preferred manner, the zeolite of the catalyst exhibits an Si / Al molar ratio of elemental silicon to elemental aluminum of 11 to 300, preferably 11 to 40.

[0032] Advantageously, the binder of the catalyst is an inorganic compound, which is generally inert, particularly with respect to alcohols, and particularly inert with respect to ethanol. Preferably, the binder is a siliceous binder such as silica, and particularly amorphous silica; clays such as kaolin, kaolinite, montmorillonite, attapulgite, talc, and bentonite; or mixtures thereof. Preferably, the binder comprises a siliceous binder, preferably consists of a siliceous binder, and is preferably amorphous silica or a mixture of amorphous silicas.

[0033] According to the present invention, the catalyst contains phosphorus. Preferably, relative to the total weight of the catalyst, the content of phosphorus element in the catalyst is 0.5 wt% to 20.0 wt%, preferably 0.5 wt% to 10.0 wt%, preferably 1.0 wt% to 5.0 wt%, and preferably 2.0 wt% to 4.0 wt% in a preferred manner. In a specific form of the present invention, the zeolite of the catalyst is modified with phosphorus.

[0034] Advantageously, the catalyst contains an AlPO structure.

[0035] The structure of the aluminum-containing entity can be shown and quantified by nuclear magnetic resonance or NMR spectroscopy of aluminum-27 atoms using magic angle spinning (MAS) in the solid state (or 27 Al NMR). The characterization by MAS 27 Al NMR is carried out using a Bruker Avance 500 spectrometer with a 4 mm zirconia MAS probe at a spinning speed of 15 kHz. To obtain a quantitative spectrum, a single excitation pulse is applied with a short excitation length of 0.6 psec. Each spectrum obtained is the result of 5000 scans at intervals of 0.5 seconds. The chemical shift in the 27 Al NMR spectrum is determined relative to a reference 0.1 M AlCl3 solution (chemical shift of 0 ppm). Preferably, the solid sample is dehydrated before 27 Al MAS NMR analysis: for example, the sample is placed in a desiccator in the presence of a saturated NH4NO3 solution for 24 hours and then transferred to the NMR spectrometer without contact with air or moisture.

[0036] The presence of the AlPO structure in the catalyst according to the present invention is determined by 27 Al NMR method, and there is a signal between 35 and 45 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst. The proportion of the AlPO structure in the catalyst according to the present invention is determined by generating from the 27The ratio of the surface area of the signal (or peak) between 35 and 45 ppm in the spectrum obtained by Al NMR analysis to the total surface area measured between -50 and 100 ppm in the Al NMR spectrum of the catalyst. 27 is determined.

[0037] Preferably, the content of the AlPO structure in the catalyst accounts for 15% to 40%, preferably 20% to 35%, and in a preferred manner 25% to 34% of the aluminum-containing entities of the catalyst.

[0038] Preferably, the zeolite of the catalyst is modified with phosphorus and exhibits an AlPO structure as part of its structure. According to a preferred embodiment, the binder of the catalyst does not contain any aluminum-containing entities; preferably, the binder is a silica binder, and the content of the AlPO structure of the catalyst corresponds to the content of the AlPO structure of the zeolite (since the zeolite is the only source of aluminum in the entire catalyst). Thus, in this preferred embodiment where the binder of the catalyst does not contain any aluminum-containing entities, preferably a silica binder, as part of its structure, the zeolite exhibits an AlPO structure, and the content of the AlPO structure of the zeolite accounts for 15% to 40%, preferably 20% to 35%, and in a preferred manner 25% to 34% of the aluminum-containing entities of the zeolite.

[0039] The pore volume of the catalyst according to the present invention described in detail below is measured by mercury volumetry analysis described in detail below. More specifically, at a maximum pressure of 4000 bar, using a surface tension of 484 dynes / cm and a contact angle of 141°, the pore volume of the catalyst is measured by intrusion with a mercury porosimeter according to standard ASTM D4284-83. According to the recommendation on page 1050 of the publication “Techniques de l’ingénieur, traité analyse et caractérisation” [Engineering Techniques, Analysis and Characterization Treatise] by J. Charpin and B. Rasneur, the wetting angle is taken to be 110°. For better accuracy, the mercury volume value in ml / g given below corresponds to the total mercury volume value in ml / g measured on the sample minus the mercury volume value in ml / g measured on the same sample for a pressure corresponding to 30 psi (about 2 bar).

[0040] According to the present invention, the pore volume (V (4-900) ) of the pores of the catalyst having a size of 4 to 900 nm (more specifically 3.6 nm to 900 nm) is greater than or equal to 0.25 ml / g, preferably greater than or equal to 0.250 ml / g, preferably greater than or equal to 0.26 ml / g, and actually even greater than or equal to 0.260 ml / g. Preferably, the pore volume (V (4-900.0) ) of the pores of the catalyst having a size of 4 to 900 nm (more specifically 3.6 nm to 900 nm) is less than or equal to 1.00 ml / g, preferably less than or equal to 0.80 ml / g, and actually even less than or equal to 0.60 ml / g, thereby contributing to the satisfactory mechanical strength of the catalyst, which can then be easily handled and does not form fines in the reactor.

[0041] According to the present invention, the pore volume (V (30-310) ) of the pores of the catalyst having a size of 30 to 310 nm is less than or equal to 0.080 ml / g, preferably less than or equal to 0.070 ml / g, and generally greater than or equal to 0.01 ml / g, preferably greater than or equal to 0.02 ml / g.

[0042] Preferably, the pore volume of the pores having a size of 3 to 100 nm is less than 0.25 ml / g.

[0043] Preferably, the catalyst comprises mesopores, i.e., pores having a size of about 4 to 50 nm, and advantageously exhibits an average mesopore diameter of less than or equal to 14 nm, preferably less than or equal to 12 nm, and preferably greater than or equal to 4 nm. Preferably, the mesopore volume of the catalyst, i.e., the volume of the pores having a size of 4 to 50 nm (and more specifically measured between 3.6 and 50 nm by mercury intrusion porosimetry, i.e., by mercury volume analysis) is preferably less than or equal to 0.080, preferably less than or equal to 0.07, and generally greater than or equal to 0.01 ml / g, generally greater than or equal to 0.030 ml / g.

[0044] Very advantageously, the catalyst exhibits microporosity, i.e., pores having a size of less than 2 nm. Preferably, the catalyst exhibits a micropore volume of 0.04 to 1.5 ml / g, preferably 0.06 to 1.3 ml / g, particularly 0.06 to 1.0 ml / g.

[0045] The micropore volume of the catalyst is measured by nitrogen adsorption isotherm analysis. The micropore volume of the catalyst corresponds to the volume occupied by pores with a diameter of less than 2 nm. Nitrogen adsorption isotherm analysis corresponds to the physical adsorption of nitrogen molecules in the catalyst pores via a gradually increasing pressure at a constant temperature and provides information on the texture characteristics (pore diameter, pore type, specific surface area) of the catalyst. To determine the micropore volume, the t-method (of Lippens and De Boer) described in the periodical Journal of Catalysis (Studies on Pore Systems in Catalysts V. The t method, J. Catal., 1965, 4(3), page 319) is used. It is based on the comparison between the experimental isotherm of the microporous solid and a reference isotherm (non-porous solid) with the same chemical properties. From the Lippens-De Boer equation, the thickness t of the multilayer can be calculated using the following equation (referred to as the t-curve):

[0046]

[0047] where P / P0 is the relative pressure of nitrogen.

[0048] The micropore volume is calculated using the following equation:

[0049] Vμ (ml / g) = D * Y

[0050] where Y is the ordinate at the origin of the t-curve, and D is the density conversion factor (D = 15.468×10 -4 , a coefficient providing the conversion of gas volume to liquid volume). The selected range of t corresponds to the plateau on the curve of nitrogen adsorption volume varying with thickness t and is 0.4 to 0.8 nm.

[0051] Advantageously, the catalyst contains a metal M, preferably in the form of a metal oxide. Preferably, the metal M is selected from alkaline earth metals and rare earth metals, preferably selected from magnesium, calcium, strontium, barium, lanthanum, and cerium. Preferably, the metal M is an alkaline earth metal, preferably calcium. Very advantageously, when the catalyst contains a metal, preferably an alkaline earth metal or a rare earth metal, the content of the metal in the catalyst, expressed as the weight of the metal M element relative to the total weight of the catalyst, is 0.1 wt% to 10.0 wt%, preferably 0.5 wt% to 3.0 wt%.

[0052] Preferably, the catalyst contains a low content of alkali metals (especially sodium), in particular less than or equal to 1000 ppm by weight, preferably less than or equal to 600 ppm.

[0053] Catalysts exhibiting such a composition and such texture characteristics enable excellent performance quality to be achieved in the reaction of alcohol dehydration to obtain the corresponding olefin having the same number of carbon atoms, particularly in the reaction of ethanol dehydration to obtain ethylene, while having satisfactory mechanical strength, thereby enabling the catalyst to be handled in an industrial-type unit and thus used.

[0054] The present invention also relates to the use of a catalyst according to the present invention in a process for dehydrating an alcohol to obtain an olefin having the same number of carbon atoms, particularly for dehydrating ethanol to obtain ethylene, said process being advantageously carried out at a temperature of 250°C to 550°C, preferably 300°C to 500°C, and at an absolute pressure of 0.1 to 1.7 MPa, preferably 0.2 to 1.3 MPa, and at a weight hourly space velocity of 0.1 to 30 h -1 and preferably 0.5 to 25 h -1 The weight hourly space velocity is defined as the ratio of the weight flow rate of pure alcohol, particularly ethanol, to the weight of the catalyst.

[0055] Another subject of the present invention is a process for preparing an olefin from a feedstock containing an alcohol, preferably for preparing ethylene from a feedstock containing ethanol, said process comprising a dehydration stage of the alcohol, preferably ethanol, said stage being carried out in the presence of a catalyst according to the present invention and at an inlet temperature of 250°C to 550°C, preferably 300°C to 500°C (i.e., the temperature of the feedstock at the inlet of the dehydration stage), at an inlet pressure of 0.1 to 1.7 MPa, preferably 0.1 to 1.3 MPa (i.e., the pressure of the feedstock at the inlet of the dehydration stage), and at a weight hourly space velocity of 0.1 to 30 h -1 and preferably 0.5 to 25 h -1 The weight hourly space velocity is defined as the ratio of the weight flow rate of the alcohol, particularly ethanol, contained in the feedstock to the weight of the catalyst. The reaction effluent is advantageously recovered at the outlet of the dehydration stage. The reaction effluent contains water and the target olefin, which is advantageously produced by the conversion of the alcohol, preferably ethanol, contained in the feedstock. The reaction effluent may also contain other compounds, which are by-products or may already be present in the feedstock.

[0056] Advantageously, the feedstock at the inlet of the process contains at least 20% by weight, preferably at least 50% by weight, preferably at least 60% by weight and preferably at least 85% by weight of alcohol, preferably ethanol.

[0057] Preferably, the process for preparing an olefin from a feedstock containing an alcohol, preferably for preparing ethylene from a feedstock containing ethanol, includes a stage of partially or completely evaporating the feedstock upstream of the dehydration stage. The evaporation stage can be carried out by heat exchange, particularly with the reaction effluent obtained from the dehydration stage.

[0058] Very advantageously, the preparation method includes at least one stage of purifying the reaction effluent downstream of the dehydration stage. In particular, the preparation method includes a stage of fractionating the reaction effluent into at least one effluent containing the target olefin (such as ethylene) and an effluent containing water.

[0059] The following examples are presented by way of illustration and do not limit the present invention. Examples

[0060] Example 1

[0061] The pore volume of the catalyst was measured according to the mercury intrusion porosimetry method described above herein. The presence and quantification of the AlPO structure in the catalyst were determined by 27 Al NMR analysis as described above. The content of the AlPO structure is expressed as a percentage of the aluminum-containing entities and is calculated by the ratio of the surface area of the signal between 35 and 45 ppm to the surface area of the signal between -50 and 100 ppm in the obtained spectrum.

[0062] Two catalysts were analyzed. Both of these catalysts contain ZSM-5 zeolite (CBV2320 from Zeolyst) and amorphous silica (a mixture of colloidal silica and silica sol) as a binder. They also both contain phosphorus and calcium. The compositional characteristics, textural characteristics, and significant SPCS values of their mechanical strength of these catalysts are presented in Table 1 below.

[0063] Table 1

[0064]

[0065] Catalyst A exhibits a pore volume V of pores with a size of 3.6 to 900 nm equal to 0.236 ml / g, that is, less than 0.25 ml / g (4-900) , and a pore volume V of pores with a size of 30 to 310 nm equal to 0.0852 ml / g, that is, less than or equal to 0.080 ml / g (30-310) . Catalyst A thus does not conform to the present invention.

[0066] Catalysts A and B were tested in a catalytic test for the dehydration of ethanol to produce ethylene.

[0067] Example 2: Catalytic test of a feedstock containing 95 wt% ethanol

[0068] The feedstock containing 95 wt% ethanol and 5 wt% water was tested on a catalytic test unit, which included a fixed bed operating in the following flow pattern. The catalyst was loaded into a 316l stainless steel reactor with an inner diameter of 13 mm. The catalyst was then activated at 450 °C in air at 6 l / h for one hour during a stationary phase while the temperature was increased at 10 °C / min. Subsequently, the temperature was reduced to the test temperature in nitrogen at 6 l / h in order to remove the air present in the system before injecting the alcohol feedstock.

[0069] The feedstock was evaporated in a line heated to 150 - 180 °C upstream of the reactor and then injected into the catalytic reactor.

[0070] The operating conditions during the dehydration process were as follows:

[0071] - Inlet temperature 390 °C,

[0072] - Inlet pressure 0.2 MPa absolute pressure

[0073] - WHSV (weight of pure ethanol feedstock / weight of catalyst / hour) 21 h -1 。

[0074] Each of catalysts A and B was tested separately.

[0075] Analysis of the reaction effluent was carried out at the reactor outlet on an on-line gas chromatograph equipped with two columns, which made it possible to determine the ethanol conversion, the yields of the various products, and the ethylene selectivity.

[0076] The ethanol conversion corresponds to the amount of ethanol converted relative to the amount of ethanol introduced (expressed as wt%).

[0077] The yield corresponds to the amount of the product under consideration in the reaction effluent relative to the amount of carbon-based ethanol introduced (expressed as wt%).

[0078] The ethylene selectivity corresponds to the amount of ethylene recovered in the reaction effluent relative to the total amount of carbon-based products in the reaction effluent (i.e., excluding water).

[0079] The results obtained are presented in the following table.

[0080] Table 2

[0081]

[0082]

[0083] It is obvious that even when the conversion rate of ethanol is the same (99.94%), catalyst B according to the present invention (selectivity 97.1%) enables an ethylene selectivity that is 1.4 percentage points higher than the ethylene selectivity (selectivity 95.7%) obtained with catalyst A not according to the present invention. Catalyst B according to the present invention enables the formation of undesirable compounds (C4, C5+ and other oxygen-based impurities, diethyl ether and acetaldehyde) to be limited to 2.75% (1.17 + 1.18 + 0.00 + 0.40), while the undesirable compounds produced using catalyst A according to the present invention are 4.12% (1.91 + 1.63 + 0.00 + 0.58).

[0084] Example 3: Catalytic test of a raw material containing 25% by weight of ethanol

[0085] A feedstock containing 25% by weight of ethanol and 75% by weight of water was tested on the same catalytic test unit as described in Example 2. The catalyst was loaded and activated as described in Example 2.

[0086] The feedstock was evaporated in a line heated to 150 - 180 °C upstream of the reactor and then injected into the catalytic reactor.

[0087] The operating conditions during the dehydration process were as follows:

[0088] - Inlet temperature 380 °C,

[0089] - Inlet pressure 0.2 MPa absolute pressure

[0090] - WHSV (weight of feedstock / weight of catalyst / hour) 7 h -1 .

[0091] Each of catalysts A and B was tested separately.

[0092] As described in Example 2, the analysis of the reaction effluent was carried out on an on-line gas chromatograph at the reactor outlet. The ethanol conversion rate, the yields of different products and the ethylene selectivity were determined as described in Example 2.

[0093] The results obtained are presented in the following table.

[0094] Table 3

[0095]

[0096]

[0097] The ethanol conversion rates of the two catalysts are the same (99.99%). However, starting from a feedstock containing 25% ethanol and under the test conditions of Example 3, catalyst B according to the present invention (selectivity 98.75%) enables an ethylene selectivity to be achieved that is approximately 1 percentage point higher than the ethylene selectivity (selectivity 97.73%) obtained with catalyst A that is not according to the present invention.

Claims

1. A catalyst, said catalyst comprising a zeolite and a binder, said zeolite exhibiting at least a series of channels with openings of at least 10 oxygen atoms (10MR), wherein: - The catalyst contains phosphorus and has an AlPO structure, which is determined by a signal between 35 and 45 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst; - The pore volume (V (4-900) ) of the pores of the catalyst with a size of 3.6 to 900 nm is greater than or equal to 0.25 ml / g; - The pore volume (V (30-310) ) of pores with a size of 30 to 310 nm of the catalyst is less than or equal to 0.080 ml / g.

2. The catalyst as claimed in claim 1, wherein the content of the AlPO structure in the catalyst accounts for 15% to 40%, preferably 20% to 35% and in a preferred manner 25% to 34% of the aluminum-containing entities of the catalyst, and the content of the AlPO structure corresponds to the ratio of the surface area of the signal between 35 and 45 ppm to the total surface area of the signals between -50 and 100 ppm in the spectrum obtained by 27 Al NMR analysis of the catalyst.

3. The catalyst as claimed in claim 1 or 2, wherein the pore volume (V (4-900) ) of the pores of the catalyst having a size of 3.6 to 900 nm is greater than or equal to 0.26 ml / g, and preferably less than or equal to 1.00 ml / g, more preferably less than or equal to 0.60 ml / g.

4. The catalyst as claimed in any one of the preceding claims, wherein the pore volume (V (30-310) ) of pores having a size of 30 to 310 nm of the catalyst is less than or equal to 0.070 ml / g.

5. The catalyst as claimed in any one of the preceding claims, wherein the binder is a silica binder or clay, preferably amorphous silica or a mixture of amorphous silicas.

6. The catalyst as claimed in any one of the preceding claims, wherein the zeolite exhibits at least a series of channels with openings of at least 10 oxygen atoms (10MR), preferably the zeolite is a zeolite whose structure is selected from the MFI, MTT, FER, MEL, TON, MWW, EUO, and MFS structures, preferably the zeolite has an MFI structure, and in a preferred manner the zeolite is ZSM-5 zeolite.

7. The catalyst as claimed in any one of the preceding claims, wherein the zeolite exhibits an Si / Al molar ratio of 11 to 300, preferably 11 to 40.

8. The catalyst as claimed in any one of the preceding claims, wherein, relative to the total weight of the catalyst, the zeolite content of the catalyst is 5.0 wt% to 95.0 wt%, preferably 15.0 wt% to 95.0 wt%, preferably 50.0 wt% to 90.0 wt%, and in a preferred manner 65.0 wt% to 85.0 wt%.

9. The catalyst as claimed in any one of the preceding claims, wherein, relative to the total weight of the catalyst, the phosphorus element content of the catalyst is 0.5 wt% to 20.0 wt%, preferably 0.5 wt% to 10.0 wt%, preferably 1.0 wt% to 5.0 wt%, and in a preferred manner 2.0 wt% to 4.0 wt%.

10. The catalyst as claimed in any one of the preceding claims, which contains a metal, preferably a metal selected from magnesium, calcium, strontium, barium, lanthanum, and cerium, very preferably calcium, and the content of the metal in the catalyst is 0.1 wt% to 10.0 wt%, preferably 0.5 wt% to 3.0 wt%, relative to the total weight of the catalyst.

11. Use of the catalyst as claimed in any one of the preceding claims in a process for the dehydration of an alcohol to obtain an olefin having the same number of carbon atoms, in particular in a process for the dehydration of ethanol to obtain ethylene.

12. A method for preparing ethylene from a raw material containing ethanol, the method comprising a stage of ethanol dehydration carried out in the presence of a catalyst as claimed in any one of claims 1 to 10, at an inlet temperature of 250 °C to 550 °C, at an inlet pressure of 0.1 to 1.7 MPa and at a weight hourly space velocity of 0.1 to 30 h -1 -1.

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