One-step process for producing dimethyl ether

Abstract

The invention relates to a process for converting ammonia (NH3) and COX (wherein x = 1-2) to dimethyl ether (DME), in which a feed comprising NH3 and COX (wherein x = 1-2) is provided to a reactor to obtain a reaction product comprising DME, wherein the reactor comprises a catalyst for converting NH3 to nitrogen (N2) and hydrogen (H2), a catalyst for converting H2 and COX (wherein x = 1-2) to DME, and an adsorbent material capable of adsorbing water. The invention also relates to a composition comprising a catalyst for the conversion of NH3 to nitrogen (N2) and hydrogen (H2), an adsorbent material for the conversion of H2 and COX (wherein x = 1-2) to DME and capable of adsorbing water, and the use of the composition in the conversion of ammonia (NH3) and COX (wherein x = 1-2) to dimethyl ether (DME).

Description

introduction

[0001] Dimethyl ether (DME) is a valuable compound useful in the chemical industry, for example as a precursor for the production of dimethyl sulfate, acetic acid or olefins. It is an important research chemical, and is used as a refrigerant and propellant. In addition, DME may be more widely used in the future because it is being developed as a new fuel, for example as a substitute or additive for propane in LPG, and as a diesel fuel additive. DME can be produced by the catalytic hydrogenation of CO, for example using synthesis gas (a fuel gas mixture mainly consisting of hydrogen and carbon monoxide). This can be done directly or by first converting synthesis gas into methanol. The direct method of producing DME by synthesis gas involves contacting synthesis gas with a bifunctional catalyst comprising a methanol synthesis catalyst and a methanol dehydration catalyst, thereby not requiring separation and purification of methanol.

[0002] A reaction scheme has been developed for the synthesis of dimethyl ether from synthesis gas: Methanol synthesis: Water Gas Shift: Methanol dehydration: Overall reaction:

[0003] Since syngas is usually derived from non-renewable sources, alternative feedstocks are considered for the production of DME. One option is to utilize CO2 such as that obtained from CO2 capture (Mota et al., Catalysts [Catalyst] 11, 411, 2021). CO2 can be combined with H2 and converted into DME, and the overall reaction equation is: For DME synthesis, a combination of CO and CO2 is generally used as a raw material. The conversion of both CO and CO2 with H2 is a balanced reaction. The reaction efficiency can be improved by capturing water by an adsorbent capable of adsorbing water, as described in WO 2017 / 121817 and by Van Kampen et al. (Reaction Chemistry & Engineering [Reaction Chemistry and Engineering], 6 (2), 244-257 (2021)). The method of WO 2017 / 121817 and Van Kampen et al. is referred to as SEDMES (adsorption enhanced dimethyl ether synthesis). The reaction is preferably carried out at a high pressure of up to 200 absolute bar and a relatively low temperature of about 250 ° C.

[0004] H2 for the SEDMES method can be derived from, for example, electrolyzed water using green electricity. The disadvantage of H2 is that storage and transportation are not direct due to its low volumetric energy density. Therefore, other options for storing and transporting H2 are considered. One of these options is ammonia NH3 (Lucentini et al., Ind.Eng.Chem.Res. [Industrial and Engineering Chemistry Research], 60, 18560-18611, 2021). Ammonia can be cracked to provide H2 and N2. H2 can then be used in the SEDMES method. The use of NH3 to provide H2 for the SEDMES method has not been described in the art. One of the reasons may be that the cracking efficiency of NH3 is low, because a gaseous mixture of H2 and N2 needs to be separated after cracking. In the absence of separation, the reactant density during SME synthesis is low, as in the above reaction equation, there are 2 molecules of N2 in addition to 6 molecules of H2. In addition, it is necessary to pressurize a larger volume of gas, which is energy inefficient. NH3 cracking is typically carried out at temperatures above 500°C, preferably about 800°C-900°C, and at ambient pressure.

[0005] Therefore, there is a need for a process for producing DME that uses renewable sources and provides efficient conversion of the renewable sources. Summary of the invention

[0006] The inventors have now discovered that NH3 cracking and DME synthesis can be carried out in a one-step process. In the one-step process, there is a catalyst for converting NH3 into nitrogen (N2) and hydrogen (H2), a catalyst for converting H2 and CO X (where x=1-2) is converted to a catalyst for DME and an adsorbent material capable of absorbing water. This method has several benefits.

[0007] First, due to the integration of NH3 cracking and DME synthesis, only one reactor is required, rather than a separate cracking reactor and a separate DME synthesis reactor. Capital expenditure and operating expenses will therefore be lower. In addition, due to process integration, the heat generated during DME synthesis can be transferred in situ to the endothermic cracking reaction without the need to transfer heat through a less efficient heat exchanger loop. There will be no heat loss. In addition, since in-situ heat transfer mitigates the heat generation in the reactor, less effort is required to mitigate the risk of runaway of the highly exothermic DME synthesis reaction.

[0008] As demonstrated by the inventors, conventional NH3 cracking requires very high temperatures and low pressures to achieve sufficiently high conversions. The endothermic nature of the cracking reaction combined with the positive entropy is the reason. Surprisingly, in the process of the present invention, the temperature can be significantly reduced while still achieving complete conversion of NH3 cracking. The inventors believe that by in situ coupling of H2 generation (NH3 cracking) with H2 consumption (DME synthesis), the cracking reaction is pulled towards complete conversion even at lower temperatures. The lower temperature of the cracking reaction provides less energy loss.

[0009] For conventional DME synthesis with CO and / or CO2 as raw materials, H2 needs to be provided in pressurized form because DME synthesis is carried out under high pressure. The pressurization of gases such as H2 is much more expensive and energy-inefficient than liquid pressurization. Liquid pressurization "only" requires a pump, while gas pressurization requires a complex compressor. The unexpected benefit of the present invention is also that it is no longer necessary to pressurize the H2 gas, but only the liquid NH3 needs to be pressurized. For conventional NH3 cracking, such pressurized NH3 is undesirable because it means that the pressure of the cracking reaction is higher, which has a negative impact on conversion. However, as with temperature, by the in-situ coupling of H2 generation (NH3 cracking) and H2 consumption (DME synthesis), the cracking reaction is pulled towards complete conversion even at increased pressure.

[0010] The third unexpected advantage of the in-situ coupling of H2 generation (NH3 cracking) with H2 consumption (DME synthesis) is that the recycle stream present in conventional NH3 cracking is no longer required. In conventional cracking, residual NH3 is removed from the reaction products. Due to economic considerations related to the equilibrium nature of the reaction, residual NH3 is inevitably present. It is economically unattractive to target very high conversion rates. This residual NH3 is separated into a mixture of N2 and H2 and fed back into the reactor, which obviously requires CAPEX, OPEX and energy. In addition, the cumbersome gas-gas separation of N2 and H2 can be replaced by direct liquid-gas separation of DME and N2. Compared with NH3 recycling, gas-gas separation requires even more CAPEX, OPEX and energy.

[0011] In summary, the present invention, by integrating NH3 cracking with DME synthesis, solves several problems that limit the widespread use of NH3 as a H2 carrier. Conventionally, such integration is not considered due to the very different reaction temperatures and pressures of the two reactions. In any case, the prior art does not suggest combining NH3 cracking with the synthesis of DME from CO and / or CO2, not even in a two-step process. In addition, the prediction of the results of the reactions with many reactive substances and the results of the adsorption steps involved is not direct and the technician cannot predict the results a priori. Now the inventors have demonstrated in examples that the reaction unexpectedly leads to high DME conversions, resulting in the benefits as explained. DETAILED DESCRIPTION

[0012] In a first embodiment, the present invention relates to a method for converting ammonia (NH3) and CO X (wherein x=1-2) into dimethyl ether (DME), wherein in reaction step a), a reaction mixture containing NH3 and CO X (wherein x=1-2) is provided to a reactor to obtain a reaction product comprising DME, wherein the reactor comprises a catalyst for converting NH3 into nitrogen (N2) and hydrogen (H2), a catalyst for converting H2 and CO X (wherein x=1-2) is converted into a catalyst for DME and an adsorbent material capable of adsorbing water.

[0013] The present invention also relates to a composition comprising a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x=1-2) is converted into a catalyst for DME and an adsorbent material capable of adsorbing water.

[0014] Furthermore, the present invention relates to a catalyst for converting NH3 into N2 and H2, for converting H2 and CO X (where x = 1-2) into DME, and a catalyst capable of absorbing water to convert ammonia (NH3) and CO X (wherein x=1-2) into dimethyl ether (DME) adsorbent material, preferably wherein the use involves one or more of the following: - an increase in conversion compared to the absence of the adsorbent material, - the rate of reaction is increased compared to the absence of the adsorbent material, or - The carbon selectivity towards DME is increased compared to the absence of the adsorbent material.

[0015] The present invention also relates to a reactor comprising a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X(where x=1-2) is converted into DME by a catalyst and an adsorbent material capable of absorbing water, wherein the reactor is preferably a fixed bed reactor or a fluidized bed reactor, and more preferably the reactor is a fluidized bed reactor. This embodiment can also be described as comprising a reactor, a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (where x=1-2) into DME and a system of an adsorbent material capable of absorbing water, wherein the reactor comprises a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x=1-2) into a catalyst for DME, and an adsorbent material capable of adsorbing water, wherein preferably the reactor is a fixed bed reactor or a fluidized bed reactor, more preferably the reactor is a fluidized bed reactor.

[0016] The embodiments disclosed in this document are applicable to all aspects of the invention, i.e., for converting ammonia (NH3) and CO X (wherein x = 1-2) into dimethyl ether (DME); comprising a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x = 1-2) into DME and a composition of an adsorbent material capable of absorbing water; a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x=1-2) into DME and a composition of an adsorbent material capable of absorbing water for converting ammonia (NH3) and CO X (wherein x=1-2) into dimethyl ether (DME), comprising a reactor, a catalyst for converting NH3 into N2 and H2, and a catalyst for converting H2 and CO X (wherein x=1-2) into DME, and a system comprising a catalyst for converting NH3 into N2 and H2, and a catalyst for converting H2 and CO X (where x=1-2) is converted into DME, and a reactor having an adsorbent material capable of adsorbing water. NH3 Cracking

[0017] NH3 cracking is known in the art and involves converting NH3 into N2 and H2. NH3 is referred to as ammonia. NH3 cracking may alternatively be referred to as the decomposition of ammonia. NH3 cracking is typically carried out in the presence of a catalyst for converting NH3 into N2 and H2. For reasons of enthalpy and entropy, this is typically carried out at low (atmospheric) pressure and high temperature (400°C and higher, preferably 800°C-900°C). Although high temperatures are preferred, catalysts for converting NH3 into N2 and H2 that work at lower temperatures are known in the art. Ru / supported catalysts still work at 350 (327)°C; Ru alloy catalysts still work at 300°C (Lucentini et al., Industrial & Engineering Chemistry Research, 60 (51), 18560-18611 (2021)). Other authors such as Itoh et al. (Materials Transactions, 43(11), 2763-2767 (2002)) and Hill et al. (Applied Catalysis B: Environmental, 172, 129-135 (2015)) have demonstrated catalyst activity at temperatures as low as 200°C.

[0018] In a preferred embodiment, the catalyst for converting NH3 into N2 and H2 is a catalyst that exhibits catalytic activity for converting NH3 into N2 and H2 at a temperature in the range of 200°C-300°C. In a preferred embodiment, the catalyst for converting NH3 into N2 and H2 is a metal-based catalyst, preferably the metal is selected from the list consisting of ruthenium, nickel, platinum, tantalum, rhodium, tungsten, iridium, cobalt, copper, iron, chromium, lead, lithium, manganese, vanadium, palladium, molybdenum, cerium, aluminum, strontium, zirconium, sodium, potassium, cesium and combinations thereof, more preferably the metal is ruthenium, nickel or iron, optionally in combination with other metals in minor amounts, most preferably the metal is ruthenium optionally in combination with other metals in minor amounts. Preferably the metal-based catalyst is a metal / support catalyst, a metal alloy catalyst, a metal composite catalyst and / or a metal oxide catalyst, wherein preferably the metal is selected from a list consisting of: ruthenium, nickel, platinum, tantalum, rhodium, tungsten, iridium, cobalt, copper, iron, chromium, lead, lithium, manganese, vanadium, palladium, molybdenum, cerium, aluminum, strontium, zirconium, sodium, potassium, cesium and combinations thereof, more preferably the metal is ruthenium, nickel or iron, most preferably the metal is ruthenium. Preferably, the support comprises carbon nanotubes. In a preferred embodiment, the catalyst for converting NH3 into N2 and H2 is a ruthenium / support catalyst, preferably wherein the support comprises carbon nanotubes or an iron-rare earth oxide composite catalyst, preferably wherein the rare earth is cerium.

[0019] In a preferred embodiment, the maximum water adsorption capacity of the catalyst for converting NH3 into N2 and H2 is less than 0.10 g water per gram catalyst at the temperature and pressure in step a), more preferably less than 0.04 g water per gram catalyst at the temperature and pressure in step a), even more preferably less than 0.02 g water per gram catalyst at the temperature and pressure in step a), most preferably less than 0.01 g water per gram catalyst at the temperature and pressure in step a).

[0020] The water adsorption capacity is preferably measured by leak analysis or by thermogravimetric analysis (TGA), preferably by TGA. These two methods are explained in Van Kampen et al. (Adsorption 27, 577-589 (2021)) and Ruthven (Ruthven, DM (1984). Principles of adsorption and adsorption processes. John Wiley & Sons.).

[0021] In the break-through analysis, a sample of the catalyst is first dried at 400° C. in an atmosphere not containing water vapor, and subsequently the catalyst is exposed to a gas mixture containing 40 mol % water and an inert tracer at the temperature and pressure in step a) until equilibrium is reached, wherein the time integration of the measured outlet composition yields the amount of water adsorbed. The amount of water adsorbed, expressed in weight, can be divided by the weight of the catalyst sample to obtain the water adsorption capacity in grams of water per gram of catalyst.

[0022] In the thermogravimetric analysis, a sample of the catalyst is first dried at a temperature of 400° C. in an atmosphere not containing water vapor, the catalyst is subsequently exposed to a gas mixture containing 40 mol % of water for at least 1000 seconds at the temperature and pressure in step a), and the weight increase of the dried catalyst before and after exposure to the gas mixture containing 40 mol % of water is measured. The water adsorption capacity is the weight increase divided by the weight of the dried catalyst sample.

[0023] The form of the catalyst used to convert NH3 to N2 and H2 depends on the size and type of reactor. In a preferred embodiment, the catalyst is a granular material, preferably with a particle size between 0.10 mm and 10 cm, more preferably between 0.30 mm and 5.0 cm, and even more preferably between 1.0 cm and 5.0 cm. Typically, the optimal particle size for a fluidized bed reactor is smaller than that for a fixed bed reactor; typically, the optimal particle size for an industrial scale reactor is greater than the optimal particle size for a laboratory reactor. The technician is able to select the optimal particle size for a particular reactor design. From H2 and CO XDME synthesis, where x = 1-2

[0024] CO X Represents CO, CO2 or a mixture thereof, and may also be referred to as "carbon oxides", where CO and CO2 are two carbon oxides. CO is carbon monoxide and CO2 is carbon dioxide. The value of x represents the number of oxygen atoms present for each carbon atom in the carbon oxide portion of the feedstock (i.e., CO+CO2), regardless of any additional oxygen and / or carbon atoms that may be present in the feedstock. Therefore, x is in the range of 1-2, where x=1 indicates pure CO and x=2 indicates pure CO2. Intermediate values ​​of x indicate that a mixture of CO and CO2 is present in the feedstock, which can be easily determined by a technician. For example, when x=1.9, there are 1.9 oxygen atoms per carbon atom, which means that the molar ratio of CO:CO2 is 1:9. Similarly, when x=1.5, the molar ratio of CO:CO2 is 1:1. In a preferred embodiment, x=2.

[0025] NH3 and CO in raw materials X The optimal molar ratio of NH3 to CO depends mainly on the value of x. Theoretically, based on the stoichiometric ratio of the reaction, the optimal X The molar ratio ranges from 4:3 (when x=1) to 2:1 (when x=2). X A stoichiometric amount of NH 3 is preferred, but the process according to the invention also operates successfully with superstoichiometric and even slightly substoichiometric amounts of NH 3 .

[0026] Dimethyl ether (DME) is also known as methoxymethane. X In the DME synthesis of (where x = 1-2), both methanol synthesis reaction and methanol dehydration reaction occur. X DME synthesis (where x = 1-2) is used to convert H2 and CO X The catalyst used for this reaction typically contains two functional groups; for methanol synthesis, a metal site is required, while for methanol dehydration, an acid site is required, so the catalyst is bifunctional. X (where x = 1-2) to DME are known in the art (Mota et al., Catalysts 11, 411, 2021). Van Kampen et al. (Reaction Chemistry & Engineering, 6(2), 244-257 (2021)) disclosed a catalyst that exhibits effective catalytic activity for DME synthesis in the range of 225°C-300°C.

[0027] In a preferred embodiment, for the H2 and CO X The catalyst for converting H2 to CO at a temperature in the range of 200°C to 300°C is X (wherein x = 1-2) into DME. In a preferred embodiment, it is used to convert H2 and CO X (wherein x = 1-2) into DME is selected from the catalyst for converting H2 and CO X (where x = 1-2) into DME, or a combination of a methanol synthesis catalyst and a methanol dehydration catalyst. The methanol synthesis catalyst is a catalyst that catalyzes the conversion of CO X (wherein x = 1-2) and H2 to synthesize methanol, the methanol dehydration catalyst is a catalyst that catalyzes the dehydration of methanol to DME and H2O. Any DME catalyst system known in the art is suitable for use in this regard. Suitable catalysts include copper / zinc oxide-based catalysts (Cu-ZnO-Al2O3) containing alumina, but other catalysts are also suitable. In a preferred embodiment, the catalyst used to dehydrate H2 and CO X (where x=1-2) The catalyst for conversion to DME is a copper / zinc oxide based catalyst containing alumina.

[0028] In a preferred embodiment, for the H2 and CO X (wherein x = 1-2) The maximum water adsorption capacity of the catalyst for conversion into DME is less than 0.10 grams of water per gram of catalyst at the temperature and pressure in step a), more preferably less than 0.04 grams of water per gram of catalyst at the temperature and pressure in step a), even more preferably less than 0.02 grams of water per gram of catalyst at the temperature and pressure in step a), and most preferably less than 0.01 grams of water per gram of catalyst at the temperature and pressure in step a).

[0029] The water adsorption capacity is preferably measured by leak analysis or by thermogravimetric analysis (TGA), preferably by TGA. These two methods are explained in Van Kampen et al. (Adsorption 27, 577-589 (2021)) and Ruthven (Ruthven, DM (1984). Principles of adsorption and adsorption processes. John Wiley & Sons.).

[0030] In the break-through analysis, a sample of the catalyst is first dried at 400° C. in an atmosphere not containing water vapor, and subsequently the catalyst is exposed to a gas mixture containing 40 mol % water and an inert tracer at the temperature and pressure in step a) until equilibrium is reached, wherein the time integration of the measured outlet composition yields the amount of water adsorbed. The amount of water adsorbed, expressed in weight, can be divided by the weight of the catalyst sample to obtain the water adsorption capacity in grams of water per gram of catalyst.

[0031] In the thermogravimetric analysis, a sample of the catalyst is first dried at a temperature of 400° C. in an atmosphere not containing water vapor, the catalyst is subsequently exposed to a gas mixture containing 40 mol % of water for at least 1000 seconds at the temperature and pressure in step a), and the weight increase of the dried catalyst before and after exposure to the gas mixture containing 40 mol % of water is measured. The water adsorption capacity is the weight increase divided by the weight of the dried catalyst sample.

[0032] For H2 and CO X (where x = 1-2) The form of the catalyst converted to DME depends on the size and type of the reactor. In a preferred embodiment, the catalyst is a granular material, preferably with a particle size between 0.10 mm and 10 cm, more preferably between 0.30 mm and 5.0 cm, and even more preferably between 1.0 cm and 5.0 cm. Typically, the optimal particle size for a fluidized bed reactor is smaller than that for a fixed bed reactor; typically, the optimal particle size for an industrial scale reactor is greater than the optimal particle size for a laboratory reactor. A technician can select the optimal particle size for a particular reactor design. Adsorbent materials capable of absorbing water

[0033] Adsorbent materials capable of absorbing water are known in the art. The adsorbent material capable of absorbing water is preferably a molecular sieve, more preferably a zeolite, and even more preferably an LTA zeolite. Molecular sieves are materials containing pores of uniform size. Zeolites are aluminosilicate minerals containing pores of uniform size. LTA zeolite is a Linde A type zeolite. Preferably, the adsorbent material capable of absorbing water is a zeolite having a pore size of 2-50 angstroms. within the range, more preferably within range, even more preferably within range, most preferably within More preferably, the adsorbent material capable of adsorbing water is a molecular sieve with a pore size of within the range, more preferably within range, even more preferably within range, most preferably within Even more preferably, the adsorbent material capable of adsorbing water is a zeolite having a pore size in the range of within the range, more preferably within range, even more preferably within range, most preferably within LTA zeolites within the range.

[0034] In a preferred embodiment, the adsorbent material capable of adsorbing water has a molar ratio of Si to Al between 0.3:1.0 and 10.0:3.0, more preferably between 0.5:1.0 and 2.0:1.0, most preferably between 0.8:1.0 and 1.2:1.0. Equal amounts of Si and Al indicate a less acidic structure that is able to adsorb water well. Preferably, the water adsorption capacity of the adsorbent material capable of adsorbing water is at least 0.04 grams of water per gram of adsorbent material at the temperature and pressure in step a), more preferably at least 0.06 grams of water per gram of adsorbent material at the temperature and pressure in step a), even more preferably at least 0.08 grams of water per gram of adsorbent material at the temperature and pressure in step a), most preferably at least 0.10 grams of water per gram of adsorbent material at the temperature and pressure in step a).

[0035] The water adsorption capacity is preferably measured by leak analysis or by thermogravimetric analysis (TGA), preferably by TGA. These two methods are explained in Van Kampen et al. (Adsorption 27, 577-589 (2021)) and Ruthven (Ruthven, DM (1984). Principles of adsorption and adsorption processes. John Wiley & Sons.).

[0036] In the breakout analysis, a sample of the adsorbent material capable of absorbing water is first dried at 400° C. in an atmosphere not containing water vapor, and then the adsorbent material capable of absorbing water is exposed to a gas mixture containing 40 mol % water and an inert tracer at the temperature and pressure in step a) until equilibrium is reached, wherein the time integration of the measured outlet composition yields the amount of water adsorbed. The amount of water adsorbed expressed in weight can be divided by the weight of the sample of the adsorbent material capable of absorbing water to obtain the water adsorption capacity in grams of water per gram of the adsorbent material capable of absorbing water.

[0037] In the thermogravimetric analysis, a sample of the adsorbent material capable of absorbing water is first dried at a temperature of 400° C. in an atmosphere not containing water vapor, and then the adsorbent material capable of absorbing water is exposed to a gas mixture containing 40 mol % of water for at least 1000 seconds at the temperature and pressure in step a), and the weight increase of the dried adsorbent material capable of absorbing water before and after exposure to the gas mixture containing 40 mol % of water is measured. The water adsorption capacity is the weight increase divided by the original weight of the dried sample of the adsorbent material capable of absorbing water.

[0038] The form of the adsorbent material capable of absorbing water depends on the size and type of reactor. In a preferred embodiment, the adsorbent material capable of absorbing water is a granular material, preferably with a particle size between 0.10 mm and 10 cm, more preferably between 0.30 mm and 5.0 cm, even more preferably between 1.0 cm and 5.0 cm. Typically, the optimal particle size for a fluidized bed reactor is smaller than for a fixed bed reactor; typically, the optimal particle size for an industrial scale reactor is larger than the optimal particle size for a laboratory reactor. The skilled person is able to select the optimal particle size for a particular reactor design.

[0039] In a preferred embodiment, at the start of reaction step a), the adsorbent material capable of adsorbing water comprises water in an amount of less than 0.10 g of water per gram of adsorbent material at the temperature and pressure in step a), even more preferably less than 0.04 g of water per gram of adsorbent material at the temperature and pressure in step a), even more preferably less than 0.02 g of water per gram of adsorbent material at the temperature and pressure in step a), most preferably less than 0.01 g of water per gram of adsorbent material at the temperature and pressure in step a). Catalysts for converting NH3 to N2 and H2, and for converting H2 to CO X (where x=1-2) into DME and a combination of a catalyst and an adsorbent material capable of adsorbing water

[0040] The present invention also relates to a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (where x = 1-2) into DME and a combination of an adsorbent material capable of absorbing water. A catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (where x = 1-2) are different from each other in the catalyst for converting NH3 to DME and the adsorbent material capable of absorbing water. Preferably, the combination is contained in a reactor, preferably a fixed bed reactor or a fluidized bed reactor. In a preferred embodiment, the catalyst for converting NH3 to N2 and H2, the catalyst for converting H2 and CO X(where x=1-2) The catalyst converted to DME and the adsorbent material capable of absorbing water are not bonded to each other. Bonding may reduce the catalytic activity of the catalyst and / or the water adsorption capacity of the adsorbent material. In addition, bonding is expensive and provides less freedom in selecting the ratio of catalyst to adsorbent material capable of absorbing water.

[0041] In a preferred embodiment, the combination comprises a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X % of the total amount of the catalyst for converting NH3 into N2 and H2, the catalyst for converting H2 and CO into DME, and the adsorbent material capable of adsorbing water in the range of 20-90 wt.%, more preferably in the range of 30-80 wt.%, even more preferably in the range of 40-70 wt.%. Preferably, the combination comprises the catalyst for converting NH3 into N2 and H2, the catalyst for converting H2 and CO into DME, and the adsorbent material capable of adsorbing water in the range of 20-90 wt.%, more preferably in the range of 30-80 wt.%, even more preferably in the range of 40-70 wt.%. X (wherein x = 1-2) into DME and the total amount of the adsorbent material capable of absorbing water in the range of 10-50 wt.% of the catalyst for converting NH3 into N2 and H2 and in the range of 10-50 wt.% of the catalyst for converting H2 and CO X (wherein x = 1-2) into DME, more preferably the combination comprises a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x = 1-2) into DME and the total amount of the adsorbent material capable of absorbing water in the range of 20-40 wt.% of the catalyst for converting NH3 into N2 and H2 and in the range of 20-40 wt.% of the catalyst for converting H2 and CO X (where x = 1-2) into DME. In a preferred embodiment, the combination comprises a catalyst based on a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (wherein x=1-2) into DME, and the total amount of the adsorbent material capable of absorbing water in the range of 20-90 wt.% of the adsorbent material capable of absorbing water, and the catalyst for converting NH3 into N2 and H2 in the range of 10-50 wt.%, and the catalyst for converting H2 and CO in the range of 10-50 wt.% X (wherein x = 1-2) into DME, more preferably the combination comprises a catalyst based on a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X(wherein x=1-2) into DME, and the total amount of the adsorbent material capable of absorbing water in the range of 40-70 wt.% of the adsorbent material capable of absorbing water, and the catalyst for converting NH3 into N2 and H2 in the range of 20-40 wt.%, and the catalyst for converting H2 and CO in the range of 20-40 wt.% X (wherein x = 1-2) is converted into a catalyst for DME. Used to convert ammonia (NH3) and CO X (wherein x = 1-2) into dimethyl ether (DME)

[0042] Used to convert ammonia (NH3) and CO X The method for converting (wherein x=1-2) into dimethyl ether (DME) comprises a reaction step a). In a preferred embodiment, the reaction temperature is in the range of 150°C-400°C, more preferably in the range of 200°C-300°C. Too low a reaction temperature leads to a low reaction rate, while too high a reaction temperature may negatively affect the water adsorption of the adsorbent capable of adsorbing water.

[0043] In a preferred embodiment, the reaction pressure is in the range of 1-100 absolute bar, preferably in the range of 20-80 absolute bar, even more preferably in the range of 30-70 absolute bar. For entropy reasons, high pressure is advantageous. The entropy of the reaction products is lower than the entropy of the starting materials, and therefore high pressure is advantageous for achieving high conversion (Le Chatelier principle). In addition, in the case where the reaction step a) is followed by an adsorbent regeneration step b), a higher pressure allows the pressure to be significantly reduced in step b), which is beneficial for adsorbent regeneration. Higher pressures require more CAPEX and OPEX costs, so too high pressures are not cost effective.

[0044] Used to convert ammonia (NH3) and CO X The method for converting (wherein x=1-2) into dimethyl ether (DME) is carried out in a reactor. In a preferred embodiment, the reactor is a fixed bed reactor or a fluidized bed reactor, more preferably the reactor is a fluidized bed reactor.

[0045] The reactor contains a solid catalyst and a solid adsorbent material and has a gaseous feed and is typically not ideally mixed, their mixing behavior is closer to plug flow. Due to the plug flow characteristics, the gas composition in the reactor is different between the reaction zone after the inlet of the reactor and the reaction zone before the outlet of the reactor. At the inlet of the reactor, there may be a suboptimal ratio of reactants; in the case of a feed containing NH3 and CO for step a), the gas composition in the reactor is different from the reaction zone after the inlet of the reactor to the reaction zone before the outlet of the reactor. X(where x=1-2), since H2 has not yet been formed, the reverse water-gas shift reaction and the methanol synthesis reaction may not occur or occur in a limited manner in the reaction zone directly after the inlet. In a preferred embodiment, the feed in reaction step a) contains H2, preferably the feed contains H2 in the range of 1-20 mol% based on the total amount of the feed, more preferably H2 in the range of 4-10 mol% based on the total amount of the feed. In this way, the reverse water-gas shift reaction and the methanol synthesis reaction also occur in the reaction zone directly after the reactor inlet, which provides a more efficient utilization of the reactor volume. In a preferred embodiment, H2 is generated by cracking part of NH3 in a separate reactor, preferably wherein the reaction product of the cracking of part of NH3 is contained in the feed for reaction step a).

[0046] In the case of ammonia (NH3) and CO X In a preferred embodiment of the method for converting (wherein x=1-2) into dimethyl ether (DME), the carbon selectivity to DME is at least 50%, more preferably at least 70%, even more preferably at least 90%, and most preferably at least 95%. Carbon selectivity is known in the art, as described, for example, by Van Kampen et al., Reaction Chemistry & Engineering, 6(2), 244-257 (2021). Carbon selectivity is calculated on a molar basis and relates to the ratio of a specific carbon-containing substance to all carbon-containing substances in the mixture. For the reaction of ammonia (NH3) and CO X (where x = 1-2) into dimethyl ether (DME), the carbon selectivity is equal to 2·y(DME) / [y(CO)+y(CO2)+2·y(DME)+y(methanol)+y(CH4)], where y(substance) is expressed in mol / m 3 The carbon selectivity of DME is related to the amount of carbon used to convert ammonia (NH3) and CO X (wherein x=1-2) into dimethyl ether (DME) in a process of carbon selectivity of the reaction product.

[0047] Typically, for an adsorption-enhanced reaction, the adsorbent material capable of absorbing water needs to be regenerated. The regeneration of the adsorbent material capable of absorbing water involves desorbing water from the adsorbent material. In this way, the adsorbent material is ready for the adsorption of water in the next reaction step a). During the reaction step a), in addition to forming the reaction product, water is also adsorbed by the adsorbent material capable of absorbing water.

[0048] In a preferred embodiment, the method comprises a second step b) after step a) being an adsorbent regeneration step, wherein the adsorbent material is contacted with a purge gas. During adsorbent regeneration, water is desorbed from the adsorbent material capable of adsorbing water. In a preferred embodiment, the purge gas is air, N2, H2 or CO2, more preferably air. Preferably, the purge gas contains less than 5.0 mol% water, preferably less than 1.0 mol% water, most preferably less than 0.5 mol% water, based on the total amount of purge gas. Preferably, the contact with the purge gas is achieved by feeding the purge gas into the reactor.

[0049] Preferably, the process is run cyclically, wherein step b) is followed by step a). In this way, the reactors of the process alternate between mode a) and mode b), optionally in combination with further modes. Mode a) is identical to step a), mode b) is identical to step b). In terms of production plants, a continuous process is preferred, the process preferably comprising two or more reactors, more preferably three or more reactors, which contain a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X (where x=1-2) is converted into a catalyst for DME and an adsorbent material capable of adsorbing water. For this embodiment, preferably, at least one of the two or three or more reactors is in mode a). By having two or more reactors, one reactor can be in reaction mode a) while the other reactor is in adsorbent regeneration mode b). When the adsorbent material capable of adsorbing water in the reactor in reaction mode a) is saturated with water, the feed flow can be switched to the reactor in adsorbent regeneration mode b) and the reaction can continue in the reactor; thus the reactor enters reaction mode a). At the same time, the reactor containing the adsorbent material saturated with water can enter adsorbent regeneration mode b). In this way, a continuous feed flow and product flow can be maintained. In some cases, mode a) and mode b) do not have equal lengths. Therefore, in a preferred embodiment, the method includes step c) idle mode. During idle mode, no gas is fed into the reactor.

[0050] The regeneration of the adsorbent material capable of adsorbing water is usually carried out by contacting the adsorbent material with a purge gas. In order to accelerate the desorption of water, the temperature can be increased or the pressure can be reduced during contact with the purge gas. Both the temperature increase and the pressure reduction stimulate the desorption of water. In a preferred embodiment, the temperature in step b) is at least 100°C higher than the temperature in step a) and / or the pressure in step b) is at least 10 bar lower than the pressure in step a), more preferably the temperature in step b) is at least 150°C higher than the temperature in step a) and / or the pressure in step b) is at least 20 bar lower than the pressure in step a). In a preferred embodiment, the pressure in step b) is at least 10 bar lower than the pressure in step a), more preferably the pressure in step b) is at least 20 bar lower than the pressure in step a). General Definition

[0051] In this document and its claims, the verb "to comprise" and its conjugations are used in its non-limiting sense to mean including the items following the word, but not excluding items not specifically mentioned. In addition, reference to an element by the indefinite article "a / an" does not exclude the possibility that more than one of the element is present, unless the context clearly requires the presence of one and only one of the element. Thus, the indefinite article "a / an" generally means "at least one". The word "about" or "approximately" when used in conjunction with a numerical value (e.g., about 10) preferably means that the value may be the given value plus or minus 1% of the value.

[0052] The invention has been described above with reference to a number of exemplary embodiments. Modifications and alternative embodiments of some parts or elements are possible and are included within the scope of protection as defined by the appended claims. All references to literature and patent documents are hereby incorporated by reference.

[0053] Absolute bar or (absolute) bar stands for bar (absolute value) and relates to the pressure relative to a perfect vacuum as a zero reference. 1 absolute bar is 100,000 N / m 2 1 bar is 100,000 Pascals. Example 1 - Ammonia feed adsorption enhanced CO2 conversion process introduction

[0054] This example describes a process for DME synthesis enhanced by ammonia feed adsorption. The process combines ammonia cracking: With CO2, during which the following main reactions occur:

[0055] These reaction equations represent the main reactions of DME synthesis enhanced by ammonia feed adsorption. All reactions are equilibrium reactions that can be carried out with limited conversion. According to Le Chatelier's principle, up to full conversion can be achieved by in situ separation of one of the reaction products (as presented, for example, in WO 2017121817 A1). The current example discusses the combination of (1) and (5) in the presence of a water adsorbent to achieve a net reaction,

[0056] Similarly, the same process can be carried out with a carbon monoxide feed, where the same main reactions (1-5) as for CO2 conversion occur: In practice, any mixture of CO2 and CO can be used as feedstock, leading to a combination of (6) and (7). During the process, reaction (2) is able to always establish a local equilibrium between CO2 and CO in the reactor. method

[0057] The equilibrium model was constructed in Aspen Plus using the Peng-Robinson equation of state. The equilibrium constants were calculated by Aspen using Gibbs free energy minimization. Instead of constructing a separation enhanced reactor, the system was modeled using the following construct: conventional unit operations that simulate the behavior of an adsorption enhanced reaction process, which is described by Schad (Chemical engineering progress, 94 (1), 21-27, (1998)). Subsequently, (i) a stoichiometric reactor was simulated, which was fully converted according to reaction (6), i.e., a maximum amount of DME and HO was produced, (ii) a separator, which removed a variable amount of HO from the reaction mixture, and (iii) an equilibrium reactor, which established thermodynamic equilibrium according to minimization of the Gibbs free energy, i.e., the reactants and by-products were regenerated according to all relevant equilibria; reactions 1-6. In this way, the performance of the adsorption enhanced reaction can be simulated, thereby allowing the calculated equilibrium composition to vary with the residual vapor content. result The equilibrium composition as a function of the residual steam partial pressure is summarized in Table 1. The residual steam is the amount of steam present after regeneration of the adsorbent material. Without removing water, only some NH3 is cracked into N2 and H2, while most of the CO2 remains inert, as evidenced by the small amounts of CO, methanol (MeOH) and DME formed. Removing water from the reaction mixture has a significant impact on the product composition. When no water is removed, the starting materials CO2 and NH3 are present in high concentrations, and only a small amount of DME is formed (Case A). In contrast, when 99.9% of the water is removed (Case D), the DME conversion is high, and the reaction product contains almost no CO2 and NH3. Table 1. Product compositions for CO2 and NH3 fed in a stoichiometric ratio at 250°C and 50 bar (absolute) for three different degrees of water removal (all values ​​are in mol % based on the total composition). Discussion and Conclusion

[0058] As shown above, lowering the residual vapor partial pressure by in situ adsorption produces a very favorable reaction equilibrium, which allows direct conversion of NH3 and CO in a single unit operation. X (where x = 1-2) feeds produce large amounts of DME. The possibility of DME synthesis under these conditions is further supported by literature evidence for ammonia cracking and adsorption-enhanced DME synthesis at these temperatures.

[0059] In addition, experiments have shown that water removal from the reaction mixture can be achieved by relatively efficient pressure swing operation of the adsorption-enhanced reaction system (van Kampen et al., Reaction Chemistry & Engineering, 6 (2), 244-257 (2021)). Therefore, the current concept allows the direct production of valuable DME and byproduct N2 from a stoichiometric NH3-CO2 feed. Finally, although the starting materials for the current simulation are CO2 and NH3, the results are extended to CO and NH3 as starting materials and to a combination of CO and CO2 and NH3 as starting materials. The reverse water-gas shift equilibrium couples CO and CO2, which provides similar results regardless of whether CO or CO2 is present as the starting material (van Kampen, J., Efficient carbon utilization to dimethyl ether by steam adsorption enhancement, PhD thesis, Eindhoven University of Technology, 2021). Example 2 - Conventional NH3 Cracking

[0060] Simulate ammonia cracking using the modeling approach of Example 1: Therefore only equation 1 is used and the feed is pure NH3. Model simulations were performed at two different pressures; 1 bar and 50 bar. The equilibrium mole fractions of the different species are in Table 2. At lower pressure and same temperature, the H2 concentration is higher and the NH3 concentration is lower. At the same pressure and higher temperature, the H2 concentration is higher and the NH3 concentration is lower. Therefore, low pressure or high temperature is favorable for NH3 cracking. Table 2. Product compositions of NH3 cracking at different temperatures and pressures, expressed in mol% based on the total amount.

Claims

1. A method for converting ammonia (NH3) and CO X - wherein x = 1-2 - a process for converting dimethyl ether (DME), wherein in reaction step a) a reaction mixture containing NH3 and CO X A feed of - wherein x = 1-2 - is provided to a reactor to obtain a reaction product comprising DME, wherein the reactor comprises a catalyst for converting NH3 into nitrogen (N2) and hydrogen (H2), a catalyst for converting H2 and CO X -wherein x=1-2-a catalyst for conversion into DME, and an adsorbent material capable of adsorbing water.

2. The method according to claim 1, wherein: The reaction temperature is in the range of 150°C to 400°C, preferably in the range of 200°C to 300°C.

3. The method according to claim 1 or 2, wherein: The reaction pressure is in the range of 1-100 absolute bar, preferably in the range of 20-80 absolute bar, even more preferably in the range of 30-70 absolute bar.

4. A method according to any one of the preceding claims, wherein: The feed comprises H2, preferably wherein the feed comprises 1-20 mol% H2 based on the total amount of the feed.

5. A method according to any one of the preceding claims, wherein: The carbon selectivity to DME is at least 50%, preferably at least 70%, more preferably at least 90%.

6. A method according to any one of the preceding claims, wherein: The catalyst used for converting NH3 into N2 and H2 is a metal-based catalyst, preferably a metal / support catalyst, a metal alloy catalyst, a metal composite catalyst and / or a metal oxide catalyst.

7. A method according to any one of the preceding claims, wherein: For H2 and CO X - wherein x = 1-2 - the catalyst for conversion to DME is selected from the group consisting of X - wherein x = 1-2 - a bifunctional catalyst for converting H2 and CO into DME, or a combination of a methanol synthesis catalyst and a methanol dehydration catalyst, preferably for converting H2 and CO X -where x=1-2- The catalyst for conversion to DME is a copper / zinc oxide based catalyst containing alumina.

8. A method according to any one of the preceding claims, wherein: The reactor contains a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X - wherein x = 1-2 - the total amount of the catalyst converted into DME and the adsorbent material capable of absorbing water is calculated in the range of 20-90 wt. % of the adsorbent material capable of absorbing water.

9. A method according to any one of the preceding claims, wherein: The adsorbent material capable of absorbing water has a pore size of 2-50 angstroms. range, preferably within range, even more preferably The adsorbent material is preferably a molecular sieve within the range of 1,2-dimethyl-1,4-dihydro ...

10. A method according to any one of the preceding claims, wherein: The method comprises, after step a), a second step b) which is an adsorbent regeneration step, in which the adsorbent material is contacted with a purge gas.

11. The method according to claim 9 or 10, wherein: The temperature in step b) is at least 100°C higher than the temperature in step a) and / or wherein the pressure in step b) is at least 10 bar lower than the pressure in step a), preferably wherein the temperature in step b) is at least 150°C higher than the temperature in step a) and / or wherein the pressure in step b) is at least 20 bar lower than the pressure in step a).

12. The process according to any one of claims 9 to 11, comprising two or more reactors comprising a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X - wherein x = 1-2 - a catalyst for conversion into DME and an adsorbent material capable of adsorbing water, preferably wherein at least one reactor of the two or more reactors carries out step a).

13. A composition comprising a catalyst for converting NH3 into N2 and H2, a catalyst for converting H2 and CO X -wherein x=1-2-a catalyst for conversion into DME, and an adsorbent material capable of adsorbing water.

14. The composition according to claim 13 is used for converting ammonia (NH3) and CO X - wherein x=1-2 - for conversion into dimethyl ether (DME), preferably wherein the use involves one or more of the following: - an increase in conversion compared to the absence of the adsorbent material, - the rate of reaction is increased compared to the absence of the adsorbent material, or - The carbon selectivity towards DME is increased compared to the absence of the adsorbent material.

15. A reactor comprising the composition according to claim 13, preferably the reactor is a fixed bed reactor or a fluidized bed reactor, more preferably the reactor is a fluidized bed reactor.

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