Method for producing propylene through ethylene methylation

Abstract

The invention discloses a method for producing propylene through ethylene methylation, and belongs to the technical field of propylene preparation. The method provided by the invention comprises the following steps: reacting a mixture containing raw material gas and a catalyst to obtain propylene, the feed gas comprises ethylene and a methylation reagent; the catalyst comprises an acidic BIK molecular sieve and / or a modified MOR molecular sieve. According to the method disclosed by the invention, ethylene and a methylation reagent are directionally coupled to generate propylene by utilizing the shape-selective catalysis capability of the molecular sieve, and the method has the advantages of high propylene selectivity, good catalyst stability, mild reaction conditions, simple process and the like, can be applied to adjusting olefin product structures in processes of methanol to olefin (MTO), fluid catalytic cracking (FCC) and the like, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of propylene preparation, and in particular to a method for producing propylene by methylating ethylene. Background Art

[0002] Propylene is an important basic organic chemical raw material. It is currently produced mainly through processes such as naphtha steam cracking, methanol to olefins, and propane dehydrogenation. In industry, the MTO and FCC processes produce ethylene and propylene at the same time, but some downstream industries only have a single demand for propylene and need to convert ethylene into propylene in a targeted manner. Ethylene methylation to propylene provides an ideal technical route, and the development of technology for ethylene methylation to propylene is of practical significance. In addition, C1 methylation reagents such as methanol, dimethyl ether, and methyl halides can be converted into propylene through the ethylene methylation reaction, providing an important conversion path for the high-value utilization of C1 methylation reagents.

[0003] Patent WO2005 / 056504A1 discloses a method for preparing propylene from methanol and / or dimethyl ether and ethylene. Methanol and / or dimethyl ether and ethylene are reacted in the presence of a catalyst to produce propylene, and the yield of propylene can reach more than 40 mol%.

[0004] CN101130470A discloses a method for producing propylene by alkylation. A raw gas containing ethylene and a methylating agent (methanol, dimethyl ether, or a haloalkane) is contacted with a SAPO-34 or ZSM-5 molecular sieve catalyst having micropores with a pore size of 0.3 to 0.5 nm to generate a product containing propylene, wherein the product selectivity of propylene can reach more than 65%.

[0005] The catalyst for the ethylene methylation reaction is an acidic molecular sieve catalyst. In addition to the methylation reaction, ethylene polymerization and MTH reactions are also likely to occur under the catalysis of the acid center of the molecular sieve, resulting in low propylene selectivity and catalyst carbon deposition and deactivation. Therefore, there is a great technical difficulty in the production of propylene by ethylene methylation. Taking advantage of the spatial confinement of the acid center in the molecular sieve, developing a suitable molecular sieve confinement catalytic system to inhibit ethylene polymerization and MTH reactions is a key breakthrough point in achieving high selectivity of ethylene methylation to produce propylene. Summary of the invention

[0006] In order to solve the above technical problems, the present application provides a method for producing propylene by methylation of ethylene, wherein the method uses a methylating agent and ethylene as raw materials to generate propylene on a catalyst containing an acidic molecular sieve. The method is carried out in a gas-solid phase and uses a non-precious metal as a catalyst. The process is simple, the catalyst is easily available and inexpensive, and has important industrial application prospects.

[0007] In order to achieve the above-mentioned invention object, this application provides the following technical solutions:

[0008] In one aspect, the present application provides a method for producing propylene by methylating ethylene, comprising the following steps:

[0009] reacting a mixture containing a raw material gas and a catalyst to obtain propylene;

[0010] The raw gas includes ethylene and a methylating agent;

[0011] The catalyst includes acidic BIK molecular sieve and / or modified MOR molecular sieve.

[0012] Optionally, the molar ratio of ethylene to the methylating agent is 0.05 to 100:1.

[0013] Optionally, the molar ratio of ethylene to the methylating agent is independently selected from any value of 0.05:1, 1:1, 10:1, 20:1, 40:1, 60:1, 80:1, 100:1, or any range therebetween.

[0014] Optionally, the Si / Al ratio of the acidic BIK molecular sieve and the modified MOR molecular sieve is independently 6-30.

[0015] Optionally, when the catalyst is an acidic BIK molecular sieve and a modified MOR molecular sieve, the mass ratio of the acidic BIK molecular sieve to the modified MOR molecular sieve is 0.01 to 100:1.

[0016] Optionally, when the catalyst is an acidic BIK molecular sieve and a modified MOR molecular sieve, the mass ratio of the acidic BIK molecular sieve and the modified MOR molecular sieve is independently selected from any value of 0.01:1, 1:1, 10:1, 20:1, 40:1, 60:1, 80:1, 100:1 or any range value therebetween.

[0017] Optionally, the particle size of the acidic BIK molecular sieve is 0.3-0.5 nm.

[0018] Optionally, the modified MOR molecular sieve is obtained by modifying the H-MOR acidic molecular sieve with a modifier.

[0019] Optionally, the preparation method of the acidic BIK molecular sieve or H-MOR acidic molecular sieve is as follows:

[0020] The calcined molecular sieve is placed in a 0.5-1 mol / L NH4NO3 aqueous solution, ion exchange is performed at room temperature of 90°C for 0.5-10 h, washed with deionized water, the above steps are repeated 1-3 times, dried at 80-150°C, and calcined at 500-600°C to obtain the acidic BIK molecular sieve or H-MOR acidic molecular sieve.

[0021] Optionally, the modifier includes at least one of pyridine, pyridine derivatives, pyridinium salts, and quaternary ammonium salts.

[0022] Optionally, the pyridine derivative is selected from at least one compound having the structural formula shown in Formula I:

[0023]

[0024] Among them, one or two of R1, R2, R3, R4 and R5 are independently selected from any one of C1 to C4 alkyl groups, and the rest are H atoms.

[0025] Preferably, the pyridine derivative is selected from at least one of 3-methylpyridine, 2,6-dimethylpyridine and 2-ethylpyridine.

[0026] Optionally, the pyridinium salt is selected from at least one of the compounds having the structural formula shown in Formula II:

[0027]

[0028] Wherein, R1 and R2 are independently H-, F-, Br-, CH3O-, CH3-, CH3CH2-, CH3(CH2) n Any one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, wherein 0<n≤2; R3 is any one of H-, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2-; X is -F, -Cl, -Br, -I, -COOCH3, -SO4 2- , -NO3, any one of them.

[0029] Preferably, the pyridinium salt is selected from at least one of pyridinium hydrochloride, pyridinium hydrogen bromide, pyridinium hydrofluoride, methylpyridine hydrochloride, methylpyridine hydrogen bromide, methylpyridine hydrofluoride, pyridine sulfate, pyridine acetate, and pyridine nitrate.

[0030] Optionally, the quaternary ammonium salt is selected from at least one of the compounds having the structural formula shown in Formula III:

[0031]

[0032] Wherein, R1, R2, and R3 are independently CH3-, CH3CH2-, CH3(CH2) n Any one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, wherein 0<n≤2; R4 is H-, CH3-, CH3CH2-, CH3(CH2) nAny one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, C6H5-, CH3C6H4-, (CH3)2C6H3-, C6H5CH2-, wherein 0<n≤2; X is any one of -Cl, -Br, -F.

[0033] Preferably, the quaternary ammonium salt is selected from at least one of methylammonium chloride (bromide), tetraethylammonium chloride (bromide), tetrapropylammonium chloride (bromide), ethyltrimethylammonium chloride (bromide), diethyldimethylammonium chloride (bromide), triethylmethylammonium chloride (bromide), phenyltrimethylammonium chloride (bromide), and benzyltrimethylammonium chloride (bromide).

[0034] Optionally, the modification method includes adsorption pretreatment or ion exchange treatment.

[0035] Preferably, the pyridine and pyridine derivatives are pretreated by adsorption, and the pyridinium salt and quaternary ammonium salt are pretreated by ion exchange.

[0036] Optionally, the adsorption pretreatment method is that the carrier gas carries pyridine or a pyridine derivative through an H-MOR acidic molecular sieve;

[0037] The volume fraction of the pyridine or pyridine derivative in the mixed gas is 0.1 to 10%;

[0038] The carrier gas includes at least one of nitrogen, helium, CO2, and argon;

[0039] The gas volume space velocity of the adsorption pretreatment is 300-5000 mL·g -1 ·h -1 .

[0040] The temperature of the adsorption pretreatment is 150-350°C;

[0041] The adsorption pretreatment time is 0.5 to 4 hours.

[0042] Optionally, the specific method of the ion exchange treatment is as follows:

[0043] (a) adding H-MOR acidic molecular sieve to a solution containing pyridinium salt or quaternary ammonium salt according to a certain solid-liquid mass ratio, exchanging and treating at 30-100° C. for 1-8 hours, and collecting the product;

[0044] (b) washing, filtering and drying the obtained product in sequence;

[0045] (c) repeating the above steps 2 to 5 times to obtain the modified MOR molecular sieve;

[0046] The solid-liquid mass ratio in the step (a) is 1 / 10 to 1 / 100, and the concentration of the pyridinium salt or quaternary ammonium salt solution is 0.05 to 2 mol / L.

[0047] Optionally, the raw gas further includes gas I;

[0048] The volume content of the gas I in the raw gas is x, wherein 0%<x≤95%;

[0049] The gas I includes at least one of hydrogen, nitrogen, helium and argon.

[0050] Optionally, the methylating agent includes at least one of dimethyl ether, methanol, methyl chloride, methyl bromide and methyl iodide.

[0051] Optionally, the mass space velocity of the methylating agent is 0.01 to 20 h -1 .

[0052] Optionally, the mass space velocity of the methylating agent is independently selected from 0.01h -1 , 1h -1 , 5h -1 , 10h -1 , 15h -1 , 20h -1 Any value in or any range between them.

[0053] Optionally, the reaction temperature is 100 to 300°C;

[0054] The reaction pressure is 0.1-2 MPa.

[0055] Optionally, the reaction temperature is independently selected from any value of 100°C, 150°C, 200°C, 250°C, 300°C, or any range therebetween.

[0056] Optionally, the reaction pressure is independently selected from any value among 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, or any range between the two.

[0057] Optionally, the reaction is carried out in a reactor;

[0058] The reactor includes at least one of a fixed bed reactor, a fluidized bed reactor and a moving bed reactor.

[0059] Compared with the prior art, this application has the following beneficial effects:

[0060] The present application provides a method for producing propylene by methylating ethylene, which utilizes the shape-selective catalytic ability of molecular sieves to directionally couple ethylene and a methylating agent to generate propylene. The method has the advantages of high propylene selectivity, good catalyst stability, mild reaction conditions, and simple process. The method can be applied to adjust the olefin product structure of processes such as methanol to olefins (MTO) and fluid catalytic cracking (FCC), and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 This is the FTIR characterization spectrum of the acidic MOR molecular sieve sample H-3# and partially modified acidic MOR molecular sieve samples H-11#, H-23#, and H-28# of this application. DETAILED DESCRIPTION

[0063] The present application is further described below in conjunction with specific embodiments. The following are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application discloses the following preferred embodiments, they are not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make some changes or modifications are equivalent to equivalent implementation cases and are within the scope of the technical solution.

[0064] Unless otherwise specified, the raw materials in the examples of the present application were purchased from commercial sources and used directly without any special treatment.

[0065] Unless otherwise specified, the analysis methods in the examples all adopt conventional settings and conventional analysis methods of instruments or equipment.

[0066] In the examples of the present application, the elemental composition of the H-MOR acidic molecular sieve before and after modification was measured using a Magix 2424 X-ray fluorescence analyzer (XRF) from Philips, and the silicon-aluminum ratio of the mordenite did not change before and after modification.

[0067] In the examples of this application, the acidity of the molecular sieves was tested on a Bruker Vertex 70 instrument, and each spectrum was obtained by 64 scans with a resolution of 4 cm -1 , the spectrum range is 4000~1000cm -1 , all spectra were recorded at room temperature.

[0068] In the examples of the present application, the reaction raw materials and the obtained products for preparing propylene were analyzed online using an Agilent 7890A gas chromatograph (chromatographic column: HP-PLOT-Q capillary column; detector: FID).

[0069] In the examples of the present application, the conversion rate of the methylating agent and the selectivity of propylene are calculated based on the carbon molar number of the methylating agent:

[0070] Methylation agent conversion rate = [(the number of carbon moles of the methylation agent in the feed gas) - (the number of carbon moles of the methylation agent in the product)] ÷ (the number of carbon moles of the methylation agent in the feed gas) × (100%);

[0071] Propylene selectivity = (1 / 3) x (the number of carbon moles of propylene in the product) ÷ [(the number of carbon moles of the methylating agent in the feed gas) - (the number of carbon moles of the methylating agent in the product)] x (100%).

[0072] The sources of different catalysts and the silicon-aluminum ratios in the following examples are shown in Table 1.

[0073] Table 1 Sources and silicon-aluminum ratios of different catalysts

[0074]

[0075]

[0076] Example 1

[0077] Preparation of hydrogen molecular sieve:

[0078] The calcined molecular sieve in Table 1 was added to a pre-prepared 1 mol / L NH4NO3 aqueous solution with a solid-liquid mass ratio of 1:10, and the reaction was carried out at 80°C for 2 hours under stirring, and then vacuum filtered and washed with water. After three consecutive exchange reactions, the molecular sieve was dried at 120°C overnight and calcined at 550°C for 4 hours to obtain a hydrogen-type molecular sieve sample. The sample number is shown in Table 2.

[0079] Table 2 Hydrogen type molecular sieve sample number

[0080] serial number Sample name Molecular sieve Si / Al ratio H-1# H-EU-7 13 H-2# H-MOR 6 H-3# H-MOR 16 H-4# H-MOR 30 H-5# H-SSZ-13 16 H-6# HY 15 H-7# H-SAPO-34 0.15 H-8# H-Beta 20 H-9# H-ZSM-5 20

[0081] Example 2

[0082] Preparation of pyridinium salt-modified MOR molecular sieves by ion exchange:

[0083] Acidic molecular sieve samples H-2#, H-3#, and H-4# were placed in exchange solutions, ion exchange was performed under certain conditions, filtration and washing were performed, and the above steps were repeated several times after drying to obtain samples. The specific preparation conditions of each sample are shown in Table 3.

[0084] Table 3 Ion exchange sample number, composition, preparation conditions

[0085]

[0086]

[0087] Note: a means that samples H-10# to H-22# were prepared using pyridine hydrochloride, and samples H-23# to H-26# were prepared using methyl pyridine hydrochloride, ethyl pyridine hydrochloride, tetramethyl ammonium bromide, and tetraethyl ammonium chloride, respectively.

[0088] Example 3

[0089] Preparation of MOR molecular sieves modified with pyridine or its derivatives by adsorption pretreatment method:

[0090] The acidic zeolite molecular sieve samples H-2#, H-3#, and H-4# were respectively loaded into the reaction tube, heated to 550°C under a nitrogen atmosphere of 100 mL / min, maintained for 4 hours, and then the molecular sieve was treated with pyridine or its derivatives carried by nitrogen to obtain the acidic zeolite molecular sieve modified by pyridine substitution. The specific preparation conditions of each sample are shown in Table 4.

[0091] Table 4 Pretreatment sample number, composition, preparation conditions

[0092]

[0093]

[0094] Note: a means that pyridine was used for pretreatment of samples H-27# to H-40#, and 3-methylpyridine, 2,6-dimethylpyridine, and 2-ethylpyridine were used for pretreatment of samples H-41# to H-43#, respectively.

[0095] Example 4

[0096] Characterization of the prepared modified molecular sieves:

[0097] The samples prepared in Examples 1, 2 and 3 were characterized by FTIR. The specific test conditions were as follows: the pressed sample was placed in an in-situ quartz cell and heated to 400°C in a vacuum for 30 minutes for pretreatment. After pretreatment, the sample was cooled to room temperature and the infrared spectrum of the sample was collected. The results are shown in Figure 2. Figure 1 As shown. Figure 1 It can be seen that all samples have a wavelength between 3650 and 3550 cm -1 Compared with the parent hydrogen-type molecular sieve, the MOR molecular sieve modified with pyridine or its derivatives, pyridinium salts, and quaternary ammonium salts has an obvious absorption signal in the range of 3650-3550cm -1The signal is weaker, indicating that the organic nitrogen-containing compounds have entered the pores of the MOR molecular sieve, effectively modified the acidity of the sample, and occupied part of the pores.

[0098] Example 5

[0099] Conversion of ethylene and dimethyl ether to propylene over different catalysts:

[0100] 1 g of the solid acid catalyst in Examples 1, 2 and 3 (wherein, H-1#, H-10# to H-43# are experimental groups, and H-3#, H-5# to H-9# are control groups) was respectively loaded into a fixed bed reactor with an inner diameter of 10 mm and a quartz tube liner (quartz tube inner diameter 6 mm), and the temperature was raised to 350°C at 1°C / min under a nitrogen atmosphere, maintained for 4 hours, and then lowered to a reaction temperature of 300°C under a nitrogen atmosphere. In this embodiment, all the raw gas consists of dimethyl ether and ethylene. The reaction raw materials are passed through the catalyst bed from top to bottom. Among them, the mass space velocity of the dimethyl ether feed is 0.1h -1 ; The molar ratio of ethylene to dimethyl ether was 10:1, and the reaction temperature was 300°C. The catalytic reaction was run for 5 hours. The reaction results (TOS=5h) are shown in Tables 5 and 6.

[0101] Table 5 Reaction results on the catalysts of the experimental group

[0102]

[0103]

[0104]

[0105] Table 6 Reaction results on the control group catalyst

[0106] catalyst Dimethyl ether conversion rate (%) Propylene selectivity (%) Other selectivity (%) H-3# 95.17 4.39 95.61 H-5# 86.75 49.38 50.62 H-6# 36.57 26.58 73.42 H-7# 62.31 58.11 41.89 H-8# 65.37 19.90 80.10 H-9# 73.53 0.50 99.5

[0107] As shown in Table 5, the acidic zeolite molecular sieve with BIK topology can be used as a catalyst to achieve the reaction of dimethyl ether and ethylene to produce propylene with a propylene selectivity of 66%. The modified acidic MOR molecular sieve can be used as a catalyst to achieve the purpose of high conversion of dimethyl ether and ethylene to produce high selectivity propylene with a propylene selectivity of more than 95%.

[0108] Compared with the experimental data of the control group in Table 6, it can be seen that the selectivity of dimethyl ether and ethylene methylation to propylene using acidic BIK molecular sieve or modified acidic MOR molecular sieve as catalyst is much higher than that of other molecular sieves, and has excellent catalytic effect.

[0109] Example 6

[0110] Effect of combined catalysts on the conversion of dimethyl ether and ethylene to propylene:

[0111] Taking catalysts H-1# and H-28# as examples, the two were mixed in different mass ratios, and other reaction conditions were the same as those in Example 5. The results of the catalytic reaction for 5 hours are shown in Table 7.

[0112] Table 7 Reaction results of different catalyst mixing ratios

[0113] H-28# / H-1# mass ratio 0.01:1 0.02:1 1:1 10:1 50:1 100:1 Conversion rate of dimethyl ether (%) 25.91 25.86. 25.64 25.56 24.92 25.32 Propylene selectivity (%) 67.03 70.12 82.88 90.29 96.07 97.24 Selectivity of other compounds (%) 32.97 29.88 17.22 9.71 3.93 2.76

[0114] Example 7

[0115] Conversion of dimethyl ether and ethylene to propylene at different reaction temperatures:

[0116] The catalyst used was sample H-28#, the reaction temperature was 100-300°C, and the other reaction conditions were the same as those in Example 5. The results of the catalytic reaction for 5 hours are shown in Table 8.

[0117] Table 8 Reaction results at different reaction temperatures

[0118] Reactor temperature (℃) 100 180 210 240 270 300 Dimethyl ether conversion rate (%) 0.21 0.71 1.41 3.91 10.92 25.32 Propylene selectivity (%) 28.44 32.92 72.88 90.19 96.17 97.34 Selectivity of other compounds (%) 71.56 67.08 27.12 9.81 3.83 2.66

[0119] Example 8

[0120] Conversion of dimethyl ether and ethylene to propylene under different reaction pressures:

[0121] The catalyst used was sample H-28#, and the reaction pressures were 0.1 MPa, 0.5 MPa, 1.0 MPa, and 2.0 MPa, respectively, and the other conditions were the same as those in Example 5. The results of the catalytic reaction running for 5 hours are shown in Table 9.

[0122] Table 9 Reaction results at different reaction pressures

[0123] Reaction pressure (MPa) 0.1 0.5 1.0 2.0 Conversion rate of dimethyl ether (%) 25.32 65.26 75.26 85.18 Propylene selectivity (%) 97.34 90.34 87.40 83.09 Selectivity of other compounds (%) 2.66 9.66 12.60 16.91

[0124] Example 9

[0125] Producing propylene under different dimethyl ether mass space velocity conditions:

[0126] The catalyst used was H-28# sample, and the mass space velocity of dimethyl ether feed was 0.1h -1 、0.3h -1 , 0.5h -1 , 1.0h -1 , 10h -1 and 20h -1 , other conditions are the same as in Example 5. After the reaction was run for 5 hours, the reaction results are shown in Table 10.

[0127] Table 10 Reaction results of dimethyl ether at different mass space velocities

[0128]

[0129]

[0130] Example 10

[0131] Propylene production under different molar ratios of ethylene and dimethyl ether:

[0132] The catalyst used was sample H-28#, the molar ratios of ethylene to dimethyl ether were 0:1, 3:1, 5:1, 8:1, 10:1, 50:1 and 100:1, respectively, and the other conditions were the same as those in Example 5. After the reaction was run for 5 hours, the reaction results are shown in Table 11.

[0133] Table 11 Reaction results of different molar ratios of ethylene and dimethyl ether

[0134]

[0135] Embodiment 11

[0136] Propylene is prepared by using different methylating agents as raw materials:

[0137] When the catalyst used was sample H-28#, and the methylating agents were methanol, methyl chloride, methyl bromide, and methyl iodide, respectively, and other conditions were the same as in Example 2, the reaction was run for 5 hours, and the results are shown in Table 12.

[0138] Table 12 Reaction results with different methylating agents as raw materials

[0139] Methylation reagents Conversion rate (%) Propylene selectivity (%) Other selectivity (%) Methanol 17.04 97.31 2.69 Methyl chloride 11.21 88.96 11.04 Methyl bromide 13.64 86.85 13.15 Methyl iodide 15.41 84.69 15.31

[0140] Catalyst H-5# sample was used as the control group. When the methylating agents were methanol, methyl chloride, methyl bromide and methyl iodide respectively, other conditions were the same as in Example 2. The reaction was run for 5 hours. The results are shown in Table 13.

[0141] Table 13 Reaction results of different methylating agents as raw materials on the catalyst of the control group

[0142] Methylation reagents Conversion rate (%) Propylene selectivity (%) Other selectivity (%) Methanol 80.06 47.31 52.69 Methyl chloride 50.23 35.69 64.31 Methyl bromide 55.69 37.33 62.67 Methyl iodide 63.45 39.62 60.38

[0143] From the comparison of Table 12 and Table 13, it can be seen that the selectivity of different methylating agents and ethylene methylation to propylene using the modified acidic MOR molecular sieve as a catalyst is higher than that of other molecular sieves, and has an excellent catalytic effect.

[0144] Example 12

[0145] Propylene produced by conversion of methylating agents in different reactors:

[0146] The catalyst used was H-28# sample, and fixed bed, fluidized bed and moving bed were used respectively. Other conditions were the same as in Example 2. The reaction was run for 5 hours. The results are shown in Table 14.

[0147] Table 14 Reaction results of different reactors evaluated

[0148] Reactor Type Conversion rate (%) Propylene selectivity (%) Other selectivity (%) Fixed bed 25.32 97.34 2.66 Fluidized Bed 27.94 97.44 2.56 Moving bed 27.55 97.41 2.59

[0149] Embodiment 13

[0150] The reaction results of dimethyl ether and ethylene conversion to propylene at different reaction times:

[0151] The catalyst used was H-28# sample. The temperature was raised to 350°C at 1°C / min under nitrogen atmosphere and maintained for 4 hours. Then the temperature was lowered to 300°C under nitrogen atmosphere. The raw gas with the composition of dimethyl ether:ethylene:N2=1:10:19 was introduced into the reactor. The reaction pressure was 0.1MPa and the mass space velocity of dimethyl ether feed was 0.08h -1 The reactions were run for 5, 10, 20, 30, 50, 100 and 200 hours respectively. The results at different catalytic reaction times are shown in Table 15.

[0152] Table 15 Reaction results under different catalytic reaction times

[0153] Reaction time (h) Conversion rate (%) Propylene selectivity (%) Other selectivity (%) 5 25.32 97.34 2.66 10 25.27 97.44 2.56 20 25.17 97.49 2.51 30 24.71 97.47 2.53 50 24.75 97.36 2.64 100 24.59 97.25 2.75 200 23.55 97.07 2.93

[0154] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for producing propylene by methylating ethylene, characterized in that: The steps include: reacting a mixture containing a raw material gas and a catalyst to obtain propylene; The raw gas includes ethylene and a methylating agent; The catalyst includes acidic BIK molecular sieve and / or modified MOR molecular sieve.

2. The method for producing propylene by methylating ethylene according to claim 1, characterized in that: The molar ratio of ethylene to the methylating agent is 0.05 to 100:

1.

3. The method for producing propylene by methylating ethylene according to claim 1, characterized in that: The Si / Al ratio of the acidic BIK molecular sieve and the modified MOR molecular sieve is independently 6 to 30; Preferably, when the catalyst is an acidic BIK molecular sieve and a modified MOR molecular sieve, the mass ratio of the acidic BIK molecular sieve to the modified MOR molecular sieve is 0.01 to 100:

1.

4. The method for producing propylene by methylation of ethylene according to claim 1, characterized in that: The particle size of the acidic BIK molecular sieve is 0.3-0.5 nm.

5. The method for producing propylene by methylation of ethylene according to claim 1, characterized in that: The modified MOR molecular sieve is obtained by modifying the H-MOR acidic molecular sieve with a modifier; Preferably, the modifier includes at least one of pyridine, pyridine derivatives, pyridinium salts, and quaternary ammonium salts.

6. The method for producing propylene by methylation of ethylene according to claim 5, characterized in that: The pyridine derivative is selected from at least one compound having the structural formula shown in Formula I: Among them, one or two of R1, R2, R3, R4, and R5 are independently selected from any one of C1 to C4 alkyl groups, and the rest are H atoms; Preferably, the pyridinium salt is selected from at least one of the compounds having the structural formula shown in Formula II: Wherein, R1 and R2 are independently H-, F-, Br-, CH3O-, CH3-, CH3CH2-, CH3(CH2) n Any one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, wherein 0<n≤2; R3 is any one of H-, CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2-; X is -F, -Cl, -Br, -I, -COOCH3, -SO4 2- , any one of -NO3; Preferably, the quaternary ammonium salt is selected from at least one of the compounds having the structural formula shown in Formula III: Wherein, R1, R2, and R3 are independently CH3-, CH3CH2-, CH3(CH2) n Any one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, wherein 0<n≤2; R4 is H-, CH3-, CH3CH2-, CH3(CH2) n Any one of CH2-, (CH3)2CH-, (CH3)2CHCH2-, C6H5-, CH3C6H4-, (CH3)2C6H3-, C6H5CH2-, wherein 0<n≤2; X is any one of -Cl, -Br, -F.

7. The method for producing propylene by methylating ethylene according to claim 5, characterized in that: The modification method includes adsorption pretreatment or ion exchange treatment.

8. The method for producing propylene by methylating ethylene according to claim 1, characterized in that: The raw gas also includes gas I; The volume content of the gas I in the raw gas is x, wherein 0%<x≤95%; The gas I includes at least one of hydrogen, nitrogen, helium and argon.

9. The method for producing propylene by methylating ethylene according to claim 1, characterized in that: The methylating agent includes at least one of dimethyl ether, methanol, methyl chloride, methyl bromide, and methyl iodide; Preferably, the mass space velocity of the methylating agent is 0.01 to 20 h -1 .

10. The method for producing propylene by methylation of ethylene according to claim 1, characterized in that: The reaction temperature is 100-300°C; The reaction pressure is 0.1-2 MPa; Preferably, the reaction is carried out in a reactor; The reactor includes at least one of a fixed bed reactor, a fluidized bed reactor and a moving bed reactor.

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