Catalysts based on zeolite and AlPO structures with high macropore volume

Abstract

The present invention relates to a catalyst comprising a zeolite having at least one series of channels, the openings of which are at least 10 oxygen atoms (10MR), and a binder. 27 The catalyst contains an AlPO structure determined by signals at 35-45 ppm on the spectrum obtained by Al NMR analysis. The pore volume (V) of the catalyst is 3.6-900 nm in diameter. (4-900) ) is 0.25 mL / g or more, and the pore volume (V (30-310) ) is 0.080 mL / g or less. The present invention also relates to the use of the catalyst in a process for dehydrating alcohols, and to a process for producing ethylene from a feedstock comprising ethanol using the catalyst.

Description

[Technical Field]

[0001] The present invention relates to a catalyst comprising a zeolite having at least a portion of the AlPO structure, a binder, and preferably phosphorus, and exhibiting a high macropore volume. The present invention also relates to a method for preparing such a catalyst. Such a catalyst is of great interest for industrial processes involving the presence of steam at high temperatures, such as the dehydration of alcohols to give the corresponding olefins, e.g., the dehydration of ethanol to selectively produce ethylene. The present invention also relates to the use of the catalyst according to the invention in a process for the dehydration of alcohols, e.g., the dehydration of ethanol to give ethylene. [Background technology]

[0002] The use of effective catalysts is one of the keys to obtaining a viable industrial process. More particularly, the dehydration of alcohols in the presence of a catalyst to produce olefins has already been well described in the literature. The reference catalysts often used are acidic monofunctional catalysts. γ-alumina is one of the catalysts for this conversion most cited in the literature (see Non-Patent Document 1). Since the 1980s, zeolites, in particular ZSM-5, have also been used for this application (see Non-Patent Document 2). For example, Patent Document 1 describes a process for the production of ethylene from an ethanol feedstock in the presence of a dehydration catalyst containing, inter alia, a ZSM-5 zeolite treated with H3PO4 so that the P2O5 content is 3.5 wt%.

[0003] Patent Document 2 discloses a method for producing phosphorus-modified zeolite, which includes a step of treating a zeolite containing at least one 10-membered ring in its structure with steam at high temperature (steaming), followed by the introduction of phosphorus, then shaping the modified zeolite with a binder, and depositing a metal, and finally a new treatment with steam (or steaming). Patent Document 3 also discloses a method for producing phosphorus-modified zeolite, which includes a step of shaping a zeolite containing at least one 10-membered ring in its structure with a binder, a step of treating the zeolite with steam at high temperature (steaming) before or after shaping, then a step of introducing phosphorus and a metal element, and finally a new treatment with steam (steaming). Similarly, Patent Document 4 describes the use of a catalyst containing a phosphorus-modified zeolite for converting at least one alcohol into an olefin in a dehydration process to produce an olefin having the same number of carbon atoms as the alcohol, wherein the catalyst is produced by a process comprising the steps of forming a zeolite containing at least one 10-membered ring in its structure with a binder, treating the zeolite with steam at a high temperature, then introducing phosphorus and a metal element, and finally treating again with steam. Patent Document 5 discloses a catalyst comprising a phosphorus-modified zeolite partially having an AlPO structure and containing at least one 10-membered ring in its structure, and a binder, wherein the AlPO structure is 27 It is determined by the signal at 35-45 ppm in the Al NMR spectrum.

[0004] Patent Document 6 provides a method for producing C2-C5 olefins from heavier olefins and / or paraffin compounds by contacting them with a specific ZSM-5-based catalyst at high temperature, high space velocity, and low hydrocarbon partial pressure. The catalyst is treated with steam before being used in hydrocarbon conversion, contains 1 wt% to 50 wt% phosphorus-containing ZSM-5 zeolite (0.1 wt% to 10 wt% phosphorus based on the weight of the catalyst), and has a surface Si / Al ratio of 20 to 60. No metals such as Ca are introduced into the catalyst.

[0005] Patent Document 7 relates to the use of a catalyst system in the synthesis of hydrocarbons by the conversion of oxygenates to propylene at high temperatures. The catalyst system comprises a molecular sieve dispersed in a phosphorus-modified alumina matrix containing labile phosphorus and / or aluminum anions, which allows for hydrothermal stabilization of the catalyst system.

[0006] Patent document 8 also discloses a catalyst for the dehydration of ethanol to give ethylene, the catalyst comprising ZSM-5 zeolite treated with water vapor and modified with phosphorus and a binder.

[0007] AlPO aluminophosphate materials are well known in the state of the art. They exist in different Al / P atomic ratios, exhibiting acidic properties at Al / P atomic ratios >1, and even more significantly in the form of hydrogen phosphates with Al / P <1. They are known to be used as acid catalysts in the dehydration of alcohols, especially methanol (see Patent Document 9). In the state of the art, the aluminum source used for the production of AlPO aluminophosphates is generally produced by treating an external aluminum source (alumina or aluminum salt) with a phosphorus source and subsequently mixing with zeolite to prepare the catalyst. In some cases, different types of alumina or aluminum salts are simultaneously mixed with phosphorus and zeolite.

[0008] The object of the present invention is to provide a novel zeolite-based catalyst for the dehydration of ethanol to give ethylene, which allows achieving high ethanol conversion and high ethylene selectivity by limiting the formation of unwanted products (oligomers and oxygenates) while exhibiting satisfactory hydrothermal resistance. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] French Patent No. 2978145 [Patent Document 2] International Publication No. 2013 / 017499 [Patent Document 3] International Publication No. 2013 / 017497 [Patent Document 4] International Publication No. 2013 / 017496 [Patent Document 5] International Publication No. 2013 / 017498 [Patent Document 6] European Patent No. 511013 [Patent Document 7] US Patent Application Publication No. 2006 / 106270 [Patent Document 8] International Publication No. 2009 / 098262 [Patent Document 9] U.S. Patent No. 5,753,716 [Non-patent literature]

[0010] [Non-Patent Document 1] H. Knozinger and R. Kohne, "The Dehydration of Alcohols over Alumina. I: The Reaction Scheme," Journal of Catalysis (1966), Vol. 5, pp. 264-270 [Non-patent document 2] SN Chaudhuri et al., "Reactions of Ethanol over ZSM-5," ​​Journal of Molecular Catalysis, Vol. 62, pp. 289-295 (1990) Summary of the Invention [Means for solving the problem]

[0011] (Summary of the Invention) The present invention relates to a catalyst comprising a zeolite exhibiting at least one series of channels with an opening at least equal to 10 oxygen atoms (10MR), and a binder, in which: - The catalyst contains phosphorus, and 27 Contains the AlPO structure determined by signals at 35-45 ppm in the spectrum obtained by Al NMR analysis; - The pore volume (V) of catalyst pores with pore sizes of 3.6 to 900 nm (4-900) ) is 0.254 mL / g or more; - The pore volume (V) of catalyst pores with a pore size of 30 to 310 nm (30-310) ) is less than 0.080 mL / g.

[0012] Surprisingly, the inventors have found that such catalysts, exhibiting the specific composition and specific textural characteristics (porosity) according to the invention, make it possible to obtain improved performance qualities in the reaction for the dehydration of alcohols to give the corresponding olefins having the same number of carbon atoms, in particular the dehydration of ethanol to give ethylene, while exhibiting satisfactory mechanical strength. In particular, such catalysts make it possible to achieve high selectivity to the targeted olefins, more particularly ethylene, in the process for the dehydration of alcohols, while ensuring high conversions of alcohols, in particular ethanol, and optimal yields of the targeted olefins. Furthermore, such catalysts exhibit fully adequate mechanical properties, in other words, sufficient to allow their handling and use in industrial-type units. In particular, the catalysts according to the invention exhibit a single pellet crush strength (SPCS) value of at least 0.7 daN / mm, preferably at least 0.8 daN / mm.

[0013] According to a second aspect, the present invention also relates to the use of a catalyst according to the invention in a process for the dehydration of alcohols to give olefins having the same number of carbon atoms, in particular in a process for the dehydration of ethanol to give ethylene.

[0014] According to a third aspect, the present invention also relates to a process for the production of ethylene from a feedstock comprising ethanol, said process comprising the steps of: in the presence of the catalyst as defined above, an inlet temperature of 250°C to 550°C, an inlet pressure of 0.1 to 1.7 MPa and a reaction time of 0.1 to 30 h. -1 The dehydration step involves dehydrating ethanol at a weight hourly space velocity of 1000 W / m. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Description of the embodiment) Advantageously, the mechanical properties can be determined by the Single Pellet Crushing Strength (SPCS) described by the method of ASTM D6175-3, which consists in measuring the breaking strength of each particle of a representative sample containing at least 50 particles. The results are weighted by the extrudate length. The SPCS value is the average of the measured breaking strengths, expressed in units of the extrudate length (daN·mm), for all particles of the sample. -1 (expressed as

[0016] According to the present invention, the expression "... to..." means that the upper and lower limits of the interval are included in the stated range of values. If this is not the case and if the upper and lower limits are not included in the stated range, these details will be provided by the present invention.

[0017] In this document, 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 <. If limiting values ​​are involved, this information will be given by the respective expressions "greater than or equal to" (corresponding to the symbol ≧") and "less than or equal to" (corresponding to the symbol ≦").

[0018] Within the meaning of the present invention, different ranges of parameters can be used alone or in combination, for example, within the meaning of the present invention, a preferred range of values ​​for the zeolite structure can be combined with a more preferred range of values ​​for the pore volume.

[0019] Subsequently, specific embodiments of the present invention will be described, which can be used separately or in combination together without any restriction on combinations where the combination is technically feasible.

[0020] The present invention relates to a catalyst comprising a zeolite exhibiting at least one series of channels with an opening at least equal to 10 oxygen atoms (10MR), preferably of structure MFI, MTT, FER, MEL, TON, MWW, EUO and MFS, preferentially of structure MFI, suitably ZSM-5, and a binder, preferably a siliceous binder or clay, wherein: the catalyst contains phosphorus and comprises AlPO structures, the content of the catalyst in AlPO structures preferably representing 15% to 40%, preferentially 20% to 35%, and advantageously 25% to 34% of the aluminium-containing entities of the catalyst, and the presence and amount of AlPO structures in the catalyst 27 The content of AlPO structure in the catalyst is determined by the signal measured at 35-45 ppm in the spectrum obtained by Al NMR analysis. 27 It corresponds to the ratio of the surface area of ​​the signal between 35 and 45 ppm to the total surface area of ​​the signal between -50 and 100 ppm in the spectrum obtained by Al NMR analysis; - The pore volume (V) of catalyst pores with pore sizes of 3.6 to 900 nm (4-900) ) is greater than or equal to 0.25 mL / g, preferably greater than or equal to 0.250 mL / g, preferentially greater than or equal to 0.26 mL / g, indeed even greater than or equal to 0.260 mL / g, and preferably less than or equal to 1.00 mL / g, preferentially less than or equal to 0.80 mL / g, indeed even less than or equal to 0.60 mL / g; - The pore volume (V) of catalyst pores with a pore size of 30 to 310 nm (30-310) ) is 0.080 mL / g or less, preferably 0.070 mL / g or less; Advantageously, the zeolite content of the catalyst is between 5.0% and 95.0% by weight, preferably between 15.0% and 95.0% by weight, preferentially between 50.0% and 90.0% by weight and suitably between 65.0% and 85.0% by weight, relative to the total weight of the catalyst; Advantageously, the content of elemental phosphorus in the catalyst is between 0.5% and 20.0% by weight, preferably between 0.5% and 10.0% by weight, preferentially between 1.0% and 5.0% by weight and suitably between 2.0% and 4.0% by weight relative to the total weight of the catalyst; Advantageously, the catalyst comprises a metal, preferably in the form of a metal oxide, said metal being preferentially an alkaline earth metal or a rare earth metal, preferably chosen from magnesium, calcium, strontium, barium, lanthanum and cerium.

[0021] According to the invention, the catalyst comprises a zeolite exhibiting at least one series of channels whose opening is at least equal to 10 oxygen atoms, preferably equal to 10 oxygen atoms (10MR), and a binder. Highly advantageously, the zeolite content of the catalyst is between 5.0% and 95.0% by weight, preferably between 15.0% and 95.0% by weight, preferentially between 50.0% and 90.0% by weight, and suitably between 65.0% and 85.0% by weight, relative to the total weight of the catalyst. The binder content of the catalyst, in turn, is advantageously between 5.0% and 95.0% by weight, preferably between 5.0% and 85.0% by weight, preferentially between 10.0% and 50.0% by weight, and suitably between 15.0% and 35.0% by weight, relative to the total weight of the catalyst.

[0022] Advantageously, the zeolite of the catalyst according to the invention is a crystalline silicate exhibiting at least one series of channels with an opening equal to at least 10 oxygen atoms, preferably equal to 10 oxygen atoms (10MR), and is preferably selected from zeolites of the MFI, MTT, FER, MEL, TON, MWW, EUO and MFS structure. The zeolite is very preferentially an MFI type zeolite, preferably a ZSM-5 zeolite. Advantageously, the zeolite of the catalyst exhibits a molar ratio Si / Al of elemental silicon to elemental aluminum of 11 to 300, preferably 11 to 40.

[0023] Advantageously, the binder of the catalyst is an inorganic compound, which is typically inert, especially to alcohols, especially ethanol. Preferably, the binder is a siliceous binder, such as silica, especially amorphous silica; clay, such as kaolin, kaolinite, montmorillonite, attapulgite, saponite and bentonite; or a mixture thereof. Preferentially, the binder comprises, preferably consists of, a siliceous binder, preferably amorphous silica or a mixture of amorphous silicas.

[0024] According to the invention, the catalyst contains phosphorus. Preferably, the content of elemental phosphorus in the catalyst is between 0.5% and 20.0% by weight, preferably between 0.5% and 10.0% by weight, preferentially between 1.0% and 5.0% by weight, and suitably between 2.0% and 4.0% by weight, relative to the total weight of the catalyst. According to a particular embodiment of the invention, the zeolite of the catalyst is modified with phosphorus.

[0025] Advantageously, the catalyst comprises an AlPO structure.

[0026] The structure of aluminum-containing entities can be determined by nuclear magnetic resonance or NMR spectroscopy (or NMR) of aluminum-27 atoms in the solid state by magic angle spinning (MAS). 27 It can be shown and quantified by analytical methods such as MAS (Al NMR). 27 Al NMR characterization was performed using a Bruker Avance500 spectrometer equipped with a 4 mm zirconia MAS probe at a spinning speed of 15 kHz. To obtain quantitative spectra, a single excitation pulse was applied using a short excitation length of 0.6 ps. Each spectrum obtained was the result of 5000 scans separated by 0.5 s. 27 Chemical shifts in Al NMR spectra are determined relative to a 0.1 M AlCl standard solution (chemical shift 0 ppm). Preferably, the solid sample is 27Prior to Al MAS NMR analysis, the sample is dehydrated: for example, the sample is left in a desiccator in the presence of saturated NH4NO3 solution for 24 hours, and then transferred to the NMR spectrometer without contact with air or moisture. The structure of aluminum-containing entities can be determined by nuclear magnetic resonance or NMR spectroscopy (or MAS) of the aluminum-27 atom in the solid state. 27 It can be shown and quantified by analytical methods such as MAS (Al NMR). 27 Al NMR characterization was performed using a Bruker Avance500 spectrometer equipped with a 4 mm zirconia MAS probe at a spinning speed of 15 kHz. To obtain quantitative spectra, a single excitation pulse was applied using a short excitation length of 0.6 ps. Each spectrum obtained was the result of 5000 scans separated by 0.5 s. 27 Chemical shifts in Al NMR spectra are determined relative to a 0.1 M AlCl standard solution (chemical shift 0 ppm). Preferably, the solid sample is 27 Prior to Al MAS NMR analysis, the sample is dehydrated: for example, the sample is left in a desiccator in the presence of saturated NH4NO3 solution for 24 hours and then transferred to the NMR spectrometer without contact with air or moisture.

[0027] The presence of the AlPO structure in the catalyst according to the invention is 27 The Al NMR method was used to determine the 27 The proportion of AlPO structure in the catalyst according to the present invention is determined by the presence of a signal at 35-45 ppm in the spectrum obtained by Al NMR analysis. 27 of the catalyst relative to the total surface area measured in the Al NMR spectrum from -50 to 100 ppm. 27 It is determined by generating the ratio of the surface areas of the signals (or peaks) between 35 and 45 ppm in the spectrum obtained by Al NMR analysis.

[0028] Preferably, the content of AlPO structures in the catalyst represents between 15% and 40%, preferentially between 20% and 35%, and suitably between 25% and 34% of the aluminium-containing entities of the catalyst.

[0029] 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 siliceous binder, and the content of AlPO structures in the catalyst corresponds to the content of AlPO structures in the zeolite (this is because the zeolite is the only source of elemental Al in the entire catalyst). Therefore, in this preferred embodiment, in which the binder of the catalyst does not contain any aluminum-containing entities and is preferably a siliceous binder, the zeolite exhibits an AlPO structure as part of its structure, and the content of AlPO structures in the zeolite accounts for 15% to 40%, preferentially 20% to 35%, and preferably 25% to 34% of the aluminum-containing entities of the zeolite.

[0030] The pore volume of the catalyst according to the invention is measured by mercury volumetric analysis, which is described in more detail below. More specifically, the pore volume of the catalyst is measured by intrusion with a mercury porosimeter according to standard ASTM D4284-83, at a maximum pressure of 4000 bar, with a surface tension of 484 dynes / cm and a contact angle of 141°. The wetting angle was taken to be equal to 110°, in accordance with the recommendation of J. Charpin and B. Rasneur in the publication "Techniques de l'ingenieur, traite analyze et caracterisation" [Treatise on Engineering Techniques, Analysis and Characterisation], p. 1050. For better accuracy, the mercury volume values ​​(mL / g) given in the following text correspond to the total mercury volume value (mL / g) measured on the sample minus the mercury volume value (mL / g) measured on the same sample at a pressure equivalent to 30 psi (approximately 2 bar).

[0031] According to the present invention, the pore volume (V) of the catalyst pores has a size of 4 to 900 nm (more specifically, 3.6 nm to 900 nm). (4-900) ) is 0.25 mL / g or more, preferably 0.250 mL / g or more, preferentially 0.26 mL / g or more, and indeed even 0.260 mL / g or more. Preferably, the pore volume (V) of the catalyst pores has a size of 4 to 900 nm (more specifically 3.6 nm to 900 nm). (4-900.0) ) is less than or equal to 1.00 mL / g, preferentially less than or equal to 0.80 mL / g, and indeed even less than or equal to 0.60 mL / g, contributing to a satisfactory mechanical strength of the catalyst, which in turn can be easily handled and does not form fine particles in the reactor.

[0032] According to the present invention, the pore volume (V) of the catalyst pores having a pore size of 30 to 310 nm is (30-310) ) is 0.080 mL / g or less, preferably 0.070 mL / g or less, and generally 0.01 mL / g or more, preferably 0.02 mL / g or more.

[0033] Preferably, the pore volume of pores having a size of 3 to 100 nm is less than 0.25 mL / g.

[0034] Preferably, the catalyst comprises mesopores, i.e. pores having a size of about 4 to 50 nm, advantageously exhibiting an average mesopore diameter of at most 14 nm, preferably at most 12 nm, and preferentially at least 4 nm. Preferably, the mesopore volume of the catalyst, i.e. the volume of pores having a size of 4 to 50 nm (more particularly, as measured by mercury intrusion, i.e. 3.6 to 50 nm by mercury volumetric analysis), is preferably at most 0.080, preferentially at most 0.07, and generally at least 0.01 mL / g, typically at least 0.030 mL / g.

[0035] Highly advantageously, the catalyst exhibits microporosity, i.e. the pores have a size of less than 2 nm. Preferably, the catalyst has a micropore volume of 0.04 to 1.5 mL / g, preferentially 0.06 to 1.3 mL / g, in particular 0.06 to 1.0 mL / g.

[0036] The micropore volume of a catalyst is measured by analyzing its nitrogen adsorption isotherm. The micropore volume of a catalyst corresponds to the volume occupied by pores with a diameter of less than 2 nm. The analysis of the nitrogen adsorption isotherm corresponds to the physical adsorption of nitrogen molecules in the porosity of the catalyst through a gradual increase in pressure at a constant temperature, and provides information on the textural characteristics of the catalyst (pore diameter, type of porosity, specific surface area). To determine the micropore volume, the t method (of Lippens and De Boer) is used, as described in the periodical Journal of Catalysis (Studies on Pore Systems in Catalysts V. The t method, J. Catal., 1965, 4(3), p. 319). It is based on the comparison between an experimental isotherm of a microporous solid and a reference isotherm (non-porous solid) of the same chemical nature. From the Lippens-De Boer equation, the thickness t of the multilayer can be calculated by the following formula (called t plot):

[0037]

number

[0038] where P / P0 is the relative pressure of nitrogen.

[0039] The micropore volume is calculated by the following formula:

[0040]

number

[0041] where Y is the ordinate at the beginning of the curve in the t-plot, and D is the density conversion factor (D = 15.468 × 10 -4 , is a coefficient that provides the conversion rate from gas volume to liquid volume). The range of t chosen corresponds to the plateau on the curve of the adsorption volume of nitrogen as a function of thickness t, which is 0.4 to 0.8 nm.

[0042] Advantageously, the catalyst comprises a metal M, preferably in the form of a metal oxide. Preferably, said metal M is selected from alkaline earth metals and rare earth metals, preferentially from magnesium, calcium, strontium, barium, lanthanum and cerium. Preferably, said metal M is an alkaline earth metal, preferentially calcium. Highly advantageously, when the catalyst comprises a metal, preferably an alkaline earth metal or a rare earth metal, the content of said metal in the catalyst, expressed as the weight of elemental metal M relative to the total weight of the catalyst, is between 0.1% and 10.0% by weight, preferably between 0.5% and 3.0% by weight.

[0043] Preferably, the catalyst contains a low content of alkali metals, especially sodium, in particular less than 1000 ppm by weight, preferably less than 600 ppm by weight.

[0044] A catalyst of such composition and exhibiting such textural properties makes it possible to achieve excellent performance qualities in the reaction for the dehydration of alcohols to give the corresponding olefins having the same number of carbon atoms, in particular the dehydration of ethanol to give ethylene, while having satisfactory mechanical strength, and therefore makes it possible to handle it and therefore to use it in industrial-type units.

[0045] The present invention also relates to the use of the catalyst according to the invention in a process for the dehydration of alcohols to give olefins having the same number of carbon atoms, in particular the dehydration of ethanol to give ethylene, advantageously at temperatures between 250°C and 550°C, preferably between 300°C and 500°C, and pressures between 0.1 and 1.7 MPa (absolute), preferably between 0.2 and 1.3 MPa (absolute), and for 0.1 to 30 h. ?1 , preferably 0.5 to 25 hours?1 The weight hourly space velocity is defined as the ratio of the flow rate by weight of the pure alcohol, specifically ethanol, to the weight of the catalyst.

[0046] Another subject of the present invention is a process for the production of olefins from a feedstock comprising alcohols, preferably for the production of ethylene from a feedstock comprising ethanol, said process comprising a step of dehydration of an alcohol, preferably ethanol, in the presence of a catalyst according to the invention at an inlet temperature (i.e. the temperature of the feedstock at the inlet to the dehydration step) of 250° C. to 550° C., preferably 300° C. to 500° C., and an inlet pressure (i.e. the pressure of the feedstock at the inlet to the dehydration step) of 0.1 to 1.7 MPa, preferably 0.1 to 1.3 MPa, and for a period of 0.1 to 30 h. -1 , preferably 0.5 to 25 hours -1 The reaction is carried out at a weight hourly space velocity of 0.05 wt. / spatial velocity, which is defined as the ratio of the flow rate by weight of the alcohol, in particular ethanol, contained in the feedstock to the weight of the catalyst. The reaction effluent is advantageously recovered at the outlet of the dehydration stage. Said reaction effluent comprises water and the targeted olefins advantageously generated by the conversion of the alcohol, preferably ethanol, contained in the feedstock. Said reaction effluent may also comprise other compounds, by-products or possibly those already present in the feedstock.

[0047] Advantageously, the feedstock comprises at least 20% by weight, preferably at least 50% by weight, preferentially at least 60% by weight and suitably at least 85% by weight of alcohol, preferably ethanol, at the inlet of the process.

[0048] Preferably, the process for the production of olefins from an alcohol-containing feedstock, preferably for the production of ethylene from an ethanol-containing feedstock, comprises, upstream of the dehydration step, a step of partial or total vaporization of the feedstock, said vaporization step being carried out by heat exchange, in particular with the reaction effluent resulting from the dehydration step.

[0049] Highly advantageously, the production process comprises at least one stage of purification of the reaction effluent downstream of the dehydration stage, in particular a stage of fractionation of the reaction effluent into at least one effluent containing the target olefin, for example ethylene, and an effluent containing water.

[0050] The following examples are offered for illustrative purposes and not to limit the invention.

[0051] (Example) Example 1 The pore volume of the catalyst was measured according to the mercury intrusion porosimetry method described above in the text. The presence and quantification of AlPO structures in the catalyst were determined according to the method described above. 27 The content of AlPO structures was determined by Al NMR analysis. The content is expressed as a percentage of aluminum-containing entities and is calculated by the ratio of the surface area of ​​the signal between 35 and 45 ppm to the signal between -50 and 100 ppm in the obtained spectrum.

[0052] Two catalysts were analyzed. Both of these catalysts contain ZSM-5 zeolite (CBV2320 from Zeolyst) and amorphous silica as a binder (a mixture of colloidal silica and silica sol). They also contain phosphorus and calcium. The compositional and textural characteristics of these catalysts, as well as significant SPCS values ​​of their mechanical strength, are presented in Table 1 below.

[0053] [Table 1]

[0054] The pore volume V of catalyst A with a size of 3.6 to 900 nm (4-900) is equal to 0.236 mL / g, i.e., less than 0.25 mL / g, and the pore volume V of pores with a size between 30 and 310 nm is (30-310) is equal to 0.0852 mL / g, i.e., less than or equal to 0.080 mL / g. Catalyst A is therefore not in accordance with the present invention.

[0055] Catalysts A and B were tested in a catalytic test for the dehydration of ethanol to give ethylene.

[0056] Example 2: Catalytic testing of feedstock containing 95 wt% ethanol A feedstock containing 95% by weight of ethanol and 5% by weight of water was tested in a catalyst test unit equipped with a fixed bed operated in a downward flow mode. The catalyst was loaded into a stainless steel reactor with a volume of 316 L. The reactor had an internal diameter of 13 mm. The catalyst was then activated during a rest phase at 450°C under 6 L / h of air, after a temperature increase of 10°C / min. The temperature was then lowered to the test temperature under 6 L / h of nitrogen, and the alcohol feedstock was injected after removing the air present in the system.

[0057] The feedstock is vaporized in a line heated to 150-180°C upstream of the reactor and then injected into the catalytic reactor.

[0058] The operating conditions during dewatering are as follows: - Inlet temperature 390℃, - Inlet pressure 0.2MPa (absolute) - WHSV (weight of pure ethanol feedstock per hour and weight of catalyst) 21h -1 .

[0059] Each of catalysts A and B is tested separately.

[0060] The analysis of the reaction effluent is carried out at the reactor outlet by an in-line gas chromatograph equipped with two columns, which makes it possible to determine the ethanol conversion, the yields of the various products and the selectivity towards ethylene.

[0061] The ethanol conversion corresponds to the amount of ethanol converted relative to the amount of ethanol introduced (expressed in % by weight).

[0062] The yield corresponds to the amount of the product under consideration in the reactor effluent (expressed in % by weight) relative to the carbon-based input of ethanol.

[0063] The selectivity to ethylene corresponds to the amount of ethylene recovered in the reaction effluent relative to the total amount of the reaction effluent products on a carbon basis (ie, excluding water).

[0064] The results obtained are presented in the table below.

[0065] [Table 2]

[0066] It is clear that, even at the same ethanol conversion (99.94%), catalyst B according to the invention (selectivity 97.1%) makes it possible to achieve a selectivity for ethylene that is 1.4 points higher than that obtained with catalyst A not according to the invention (selectivity 95.7%). Catalyst B according to the invention makes it possible to limit the formation of unwanted compounds (C4, C5+ and other oxygen-based impurities, diethyl ether and acetaldehyde) to 2.75% (1.17 + 1.18 + 0.00 + 0.40) compared to 4.12% (1.91 + 1.63 + 0.00 + 0.58) of unwanted compounds produced with catalyst A not according to the invention.

[0067] Example 3: Catalytic testing of feedstock containing 25 wt% ethanol A feed containing 25 wt. % ethanol and 75 wt. % water was tested in the same catalyst test unit as described in Example 2. The catalyst was loaded and activated as described in Example 2.

[0068] The feedstock is vaporized in a line heated to 150-180°C upstream of the reactor and then injected into the catalytic reactor.

[0069] The operating conditions during dewatering are as follows: - Inlet temperature 380℃, - Inlet pressure 0.2MPa (absolute) - WHSV (weight of feed per hour and weight of catalyst) 7h ?1 .

[0070] Each of catalysts A and B is tested separately.

[0071] Analysis of the reaction effluent is carried out on an in-line gas chromatograph at the reactor outlet as described in Example 2. The conversion of ethanol, the yields of various products and the selectivity to ethylene are determined as described in Example 2.

[0072] The results obtained are presented in the table below.

[0073] [Table 3]

[0074] The ethanol conversion is the same for both catalysts (99.99%). However, starting from a feedstock containing 25% ethanol, under the test conditions of Example 3, catalyst B according to the invention (selectivity 98.75%) makes it possible to achieve a selectivity to ethylene that is approximately one point higher than that obtained with catalyst A not according to the invention (selectivity 97.73%).

Claims

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

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

3. The pore volume (V) of the catalyst pores having a pore size of 3.6 to 900 nm （４－９００） 3. The catalyst according to claim 1, wherein the solubility of the catalyst is greater than or equal to 0.26 mL / g and preferably less than or equal to 1.00 mL / g, preferentially less than or equal to 0.60 mL / g.

4. Pore ​​volume V of pores with a pore size of 30 to 310 nm （３０－３１０） The catalyst according to any one of claims 1 to 3, wherein the solubility of the catalyst is 0.070 mL / g or less.

5. Catalyst according to any one of claims 1 to 4, wherein the binder is a siliceous binder or a clay, preferentially amorphous silica or a mixture of amorphous silicas.

6. Catalyst according to any one of claims 1 to 5, in which the zeolite exhibits at least one series of channels with an opening at least equal to 10 oxygen atoms (10MR), preferably the zeolite is of a structure chosen from the MFI, MTT, FER, MEL, TON, MWW, EUO and MFS structures, preferentially the zeolite is of MFI structure, and suitably the zeolite is a ZSM-5 zeolite.

7. Catalyst according to any one of claims 1 to 6, wherein the zeolite has a Si / Al molar ratio of 11 to 300, preferably 11 to 40.

8. 8. The catalyst according to any one of claims 1 to 7, wherein the zeolite content of the catalyst is between 5.0% and 95.0% by weight, preferably between 15.0% and 95.0% by weight, preferentially between 50.0% and 90.0% by weight, and suitably between 65.0% and 85.0% by weight, relative to the total weight of the catalyst.

9. 9. The catalyst according to any one of claims 1 to 8, wherein the content of elemental phosphorus in the catalyst is between 0.5% and 20.0% by weight, preferably between 0.5% and 10.0% by weight, preferentially between 1.0% and 5.0% by weight, and suitably between 2.0% and 4.0% by weight, relative to the total weight of the catalyst.

10. Catalyst according to any one of claims 1 to 9, comprising a metal, preferably a metal chosen from magnesium, calcium, strontium, barium, lanthanum and cerium, highly preferentially calcium, the content of said metal of the catalyst being between 0.1% and 10.0% by weight, preferably between 0.5% and 3.0% by weight, relative to the total weight of the catalyst.

11. Use of a catalyst according to any one of claims 1 to 10 in a process for the dehydration of alcohols to give olefins having the same number of carbon atoms, in particular in a process for the dehydration of ethanol to give ethylene.

12. A process for the production of ethylene from a feedstock comprising ethanol, comprising a step of dehydrating the ethanol, the process being carried out in the presence of a catalyst according to any one of claims 1 to 10 at an inlet temperature of 250°C to 550°C, an inlet pressure of 0.1 to 1.7 MPa and for 0.1 to 30 h. ?１ This method is performed at weight-hour space velocity.

Images