KR20190131447A - Method for selective ethylene production from propane - Google Patents

Abstract

The present invention provides a method for manufacturing selective ethylene from propane, and more particularly, provides the method for producing ethylene from propane with high selectivity with a ZSM-5 catalyst having a controlled specified range of acidity. The method for selectively manufacturing ethylene from propane according to an embodiment of the present invention can produce ethylene with excellent selectivity.

Description

Method for selective ethylene production from propane

The present invention relates to a process for the selective production of ethylene from propane, and more particularly, to a process for producing ethylene with high selectivity from propylene under certain conditions and with specific zeolite catalysts for the propylene obtained by the dehydrogenation of propane.

Light olefins, ethylene and propylene, are currently the main bulk chemicals in the petrochemical market and are important raw materials used in the manufacture of various chemical products such as plastics, synthetic rubber, packaging, textiles, building materials, furniture, and the like. Because of these diverse applications, the use of ethylene and propylene in the global market is expected to continue to increase in the future.

In particular, in the case of ethylene, more than 50% of the ethylene is used in the production of polyethylene and ethylene copolymers worldwide. In addition, ethylene, hydration, oligomerization, hydroformylation, etc. Through chemical reactions, it is very important for chemical industry and is supplied with various raw compounds.

In the petrochemical industry, there are various routes to produce these light olefins, but steams for producing olefins by pyrolysing hydrocarbon raw materials such as gas raw materials (ethane, propane) and liquid raw materials (naphtha, gas oil) at high temperature with steam. The cracking process is the most commonly used process. The yield of the product obtained through this steam cracking is largely determined according to the hydrocarbon raw materials used. In the case of ethane crackers using ethane as a raw material, ethylene is mainly produced (about 83% yield), and a little fuel oil is produced. Obtained as a byproduct.

However, naphtha crackers, which currently account for the largest number of crackers operating in the world for olefin production, can obtain C4 fraction, BTX aromatic fraction and other fuels as light by-products other than ethylene and propylene, which are ethylene 32% The yield is about 16%.

Although the amount of ethylene produced in the petroleum-derived naphtha cracking process, which is the most olefin-making process, is about 2 times higher than that of propylene production, the type of hydrocarbon raw materials used and the process applied differ from region to region. Due to the different kinds of industries that use light olefins to produce chemicals, the price gap between ethylene and propylene is inevitably caused by regional demand and supply, such as the United States, Europe, China, and Asia.

Therefore, the development of olefin interconversion technology is needed to balance this regional demand for light olefins supply-demand between ethylene and propylene.

In this olefin interconversion study, the propylene production process (Ethylene-to-Propylene, ETP) has been extensively studied from ethylene due to the expectation that the price and demand of propylene will be relatively higher than that of ethylene. .

In recent years, however, many new ethane crackers have been supplied in the United States to use shale gas, a gaseous feedstock, but in Asia, as well as high demand for ethylene, naphtha crackers, propane de-hydrogenation (PDH) and MTP. Because of the many different sources of propylene, such as methanol-to-propylene, propylene is relatively cheaper than ethylene.

Therefore, there is a need to develop a process for selectively converting propylene to ethylene (Propylene-to-Ethylene, PTE) in Asia.

 In the 1960s, a triolefin process using olefin metathesis was developed and commercialized. This metathesis reaction uses a heterogeneous catalyst in which tungsten oxide is supported on a silica support, and theoretically converts 2 moles of propylene into one ethylene and 2-butene, respectively.

However, in order to maximize the ethylene yield in the process using metathesis reaction, since the ethylene one-pass selectivity is less than 35.3% in propylene self-metathesis reaction, the selectivity of ethylene is not high. The metathesis reactors of the raw material propylene and the main by-product butene and the reactors which decompose variously produced hydrocarbons must be composed essentially in series. Commercialization of selective ethylene production from propylene via metathesis routes has been discontinued for reasons such as such.

Therefore, a new process for producing ethylene is needed.

 Zeolites, on the other hand, have been used as solid acid catalysts in many catalytic processes in the chemical industry because of their unique shape selectivity and adjustable acid point. In particular, these features have led to high efficiencies in oil refinery and petrochemical processes. For example, zeolite catalysts exhibit high catalytic activity and production selectivity in a series of catalytic reactions such as cracking, isomerization, aromatization, disproportionation, alkylation. Zeolites as catalysts in ethylene production have mostly been used as additional processes in the overall process for improving the yield of light olefins, and ethylene is obtained through catalytic cracking of the reaction intermediates olefins and hydrocarbons. Ethylene selectivity was reported as low as 12-30% in this catalyst cracking.

Therefore, there is a limit to applying existing technologies and catalysts to selectively prepare ethylene, and a new process to improve this is required.

International Publication No. 2005-014169

The present invention provides a process for the selective production of ethylene from propane, the process for producing ethylene with high selectivity by contacting a propylene containing mixture prepared by the dehydrogenation of propane with a specific catalyst having a controlled range of acidity. to provide.

The present invention provides a method for selectively producing ethylene from propane, the first aspect of the method for selectively producing ethylene from propane according to an embodiment of the present invention,

a) dehydrogenating a feedstock comprising propane under a chromium-based or platinum-based catalyst to obtain a propylene-containing mixture; And

b) contacting the propylene-containing mixture obtained in the step above with an acid treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst or less to convert propylene into ethylene; It includes.

A second aspect of the process for preparing selective ethylene from propane according to one embodiment of the present invention,

Chromium-based or platinum-based catalysts; And an acid-treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst or less; and adding a feedstock including propane to the reactor including the propane. Contacting a feedstock with the chromium-based or platinum-based catalyst and the acid treated ZSM-5 catalyst to produce ethylene from propane.

Preferably, the acid treated ZSM-5 catalyst according to one embodiment of the present invention may have a weak acidity of 0.040 to 0.110 mmol / g-catalyst, a strong acidity of 0.200 to 0.410 mmol / g-catalyst, and a strong acidity / weak acidity. Degrees can be 10 to 8.0.

The acid-treated ZSM-5 catalyst according to an embodiment of the present invention may be treated with a phosphoric acid compound to support 0.5 to 5% by weight of phosphorus. The phosphoric acid compound according to the embodiment may include phosphoric acid, first ammonium phosphate salt, It may be one or two or more compounds selected from one or two or more selected from diammonium phosphate salt, (C1-C10) alkyl phosphorous acid and (C1-C10) alkyl phosphate.

The acid treated ZSM-5 catalyst according to one embodiment of the present invention may be treated with one or more acids selected from hydrochloric acid, ammonium hexafluorosilicate, oxalic acid and ammonium fluoride, wherein the ZSM-5 catalyst is treated with The acid to be made may be from 0.005 to 0.5 moles.

Preferably, the acid-treated ZSM-5 catalyst according to one embodiment of the present invention may have a Si / Al ₂ molar ratio of 23 to 280.

Preferably the chromium-based catalyst according to an embodiment of the present invention is Cr ₂ O ₃ / Al ₂ O ₃ , the platinum catalyst may be Pt-Sn / Al ₂ O ₃ .

Preferably step b) according to an embodiment of the first aspect of the invention is a temperature of 550 to 610 ℃, atmospheric pressure of 0.01 to 1MPa, hourly weight space velocity of propylene of 0.1 to 10 hours ^-1 and 1: 0.001 to 0.125 At a dilution ratio of propylene and nitrogen.

Preferably dehydrogenation according to an embodiment of the first aspect of the present invention may be carried out at a weight space velocity (WHSV) of 1 to 15h ^-1 conditions of the feedstock containing the propane at a reaction temperature of 500 to 610 ℃. .

The step according to one embodiment of the second aspect of the present invention comprises a temperature of 550 to 610 ° C., a pressure of 0.01 to 1 MPa, an hourly space velocity of propylene of 0.1 to 10 hours ⁻¹ and propylene and nitrogen of 1: 0.5 to 1.5 It may be carried out at a dilution ratio.

The method for selectively producing ethylene from propane according to an embodiment of the present invention uses propylene produced by dehydrogenation of propane as an catalyst using acid treated ZSM-5 having a specific range of acidity as a catalyst, thereby providing ethylene with excellent selectivity. It can manufacture.

Therefore, the process for producing selective ethylene from propane of the present invention is very economical because it can produce high price ethylene from low price propane with high selectivity and yield.

In addition, the method for producing selective ethylene from the propane of the present invention can be selectively produced in propylene from the propylene produced by the dehydrogenation of the existing propane can be easily applied to the existing dehydrogenation process of propane is very advantageous for commercialization. .

In addition, the method for producing selective ethylene from the propane of the present invention can produce ethylene with significantly improved ethylene selectivity, propane conversion and yield compared to the conventional method for producing ethylene by propane cracking.

1 is a view showing the XRD pattern of the catalyst prepared in Example 1 and Example 6 of the present invention.
2 is a schematic diagram of a reactor for producing selective ethylene from propane of the present invention.
3 is a graph showing propane conversion and ethylene selectivity of Example 6 of the present invention with temperature.
4 is a graph showing propane conversion and ethylene selectivity of Example 7 according to the space velocity.
5 is a graph showing the propylene conversion and ethylene selectivity of Example 9 of the present invention according to the partial pressure.
6 is a graph showing the conversion rate of propylene and the selectivity of ethylene according to the space velocity of propylene of Example 10 of the present invention.
7 is a graph showing the conversion rate of propylene and the selectivity of ethylene according to the partial pressure of propylene in Example 11.
8 is a graph showing the conversion rate of propylene and selectivity of ethylene of Example 8, Example 12, and Comparative Example 3. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated more concretely. Unless otherwise defined in the technical terms and scientific terms used at this time, have a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs, unnecessarily obscure the subject matter of the present invention in the following description Description of known functions and configurations that may be omitted.

Alkyl as described herein includes both straight and branched chains, meaning a hydrocarbon radical of 1 to 10 carbon atoms, preferably a hydrocarbon radical of 1 to 5 carbon atoms.

The present invention provides a process for the selective production of ethylene from propane, wherein the process for producing the selective ethylene from propane of the present invention can be described in two aspects.

First, the first embodiment is a series process in which a mixture containing propylene obtained from the by-product of the PDH process is obtained and reacted with a PTE process catalyst to selectively prepare ethylene from propane as illustrated on the right side of FIG. 2. . The PDH process and the PTE process may be performed in separate reactors.

The second embodiment selectively produces ethylene from propane by contacting a feedstock comprising propane in a reactor containing a PDH process catalyst and a PTE process catalyst with a PDH process catalyst and a PTE process catalyst as outlined on the left side of FIG. It is a cascade process.

The first embodiment of the method for producing selective ethylene from propane according to an embodiment of the present invention is a serise process,

a) dehydrogenating a feedstock comprising propane under a silica chromium catalyst to obtain a propylene containing mixture; And

b) contacting the propylene-containing mixture obtained in the step above with an acid treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst or less to convert propylene into ethylene; It includes.

According to a second aspect of the method for preparing selective ethylene from propane according to one embodiment of the present invention,

A feedstock comprising a silica chromium catalyst and propane added to a reactor containing an acid treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst or less and a strong acidity of 0.410 mmol / g-catalyst of Contacting the catalyst and the acid treated ZSM-5 catalyst to produce ethylene from propane.

Strong acidity and weak acidity of the acid-treated ZSM-5 catalyst according to an embodiment of the present invention is NH ₃ -TPD (temperature-programmed desorption, ammonia temperature desorption method), pre-treated by heating the sample for 60 minutes at 500 ℃ temperature After adsorbing ammonia at 100 ° C. for 30 minutes, it was desorbed ammonia physically adsorbed at He gas at 100 ° C. for 1 hour and heated to a temperature of 5 ° C./min under He gas at 900 ° C. for TCD detector (thermal conductivity). This value is obtained by using a detector.

The process for producing selective ethylene from propane of the present invention is to contact a propylene-containing mixture prepared in a PDH process for producing propylene from a propane or a mixture prepared through a PDH process in a reactor with a specific catalyst having a specific range of acidity. By converting propylene to ethylene to produce ethylene with surprisingly improved selectivity and yield with high propane conversion.

In addition, the selective production method of ethylene from the propane of the present invention is very economical by combining the PTE process of the present invention with the existing PDH process or by including the PTE process of the present invention in the existing PDH process, thus eliminating the need for additional new process equipment. .

Furthermore, the method for producing selective ethylene from propane of the present invention can produce ethylene with high selectivity by using a large amount of propane produced in the PDH process, an on-purpose process for producing propylene from cheap natural gas (mostly propane). It can solve demand-supply imbalances of propylene and ethylene.

Preferably, the acid treated ZSM-5 catalyst according to one embodiment of the present invention may have a weak acidity of 0.040 to 0.110 mmol / g-catalyst and a strong acidity of 0.200 to 0.410 mmol / g-catalyst.

The selective production method of ethylene from propane according to an embodiment of the present invention is a process catalyst for selectively producing ethylene from propylene contained in a mixture containing propylene prepared by PDH process, which is treated with acid to provide a specific range of acidity. By using ZSM-5 catalysts controlled to have, ethylene can be produced with surprisingly improved conversion and selectivity.

Acid treated ZSM-5 catalyst according to an embodiment of the present invention preferably has a weak acidity of 0.030 to 0.110 mmol / g-catalyst, a strong acidity of 0.200 to 0.410 mmol / g-catalyst, more preferably The weak acidity is 0.045 to 0.110 mmol / g catalyst and the strong acidity may be 0.180 to 0.400 mmol / g catalyst.

That is, by using the acid-treated ZSM-5 catalyst having a specific range of acidity in the PTE process (propylene to ethylene) of the method for producing a selective ethylene from propane according to an embodiment of the present invention, specifically about weak acidity and strong acidity Ethylene can be prepared in high yields and selectivity by using optionally controlled acid treated ZSM-5 catalysts.

Preferably, the acid-treated ZSM-5 catalyst according to an embodiment of the present invention may have a ratio of strong acidity / weak acidity, that is, a ratio of strong acidity divided by weak acidity, and may be 0.1 to 8.0, and preferably 0.1 to 3.0. .

In addition, the acid treated ZSM-5 catalyst of the present invention may have a total acidity of 0.30 to 0.50 mmol / g-catalyst.

Specifically, the acid-treated ZSM-5 catalyst of the present invention is treated with an acid in the general zeolite catalysts ZSM-11, ZSM-22, HY, SSZ-13, SAPO-34, SAPO-11, mordenite and beta. In contrast, it has significantly improved conversion and selectivity.

In addition, the acid-treated ZSM-5 catalyst according to one embodiment of the present invention may be described in two aspects depending on the type of acid to be treated.

The first aspect is that ZSM-5, a specific zeolite catalyst, is supported with phosphorus to slightly dealuminize to weaken the strong acid point due to the mutual attraction between the zeolite skeleton and aluminum, thereby controlling to have a controlled weak acidity and strong acidity. By increasing the selectivity of the selective ethylene from propane, these acids may be one or more selected from hydrochloric acid and phosphoric acid compounds.

When the acid treated in the acid-treated ZSM-5 catalyst according to one embodiment of the present invention is one or two or more selected from hydrochloric acid and phosphoric acid compound, the strong acid point of the ZSM-5 catalyst is weakened due to dealumination of the ZSM-5 catalyst. By adjusting the strong acid point of the ZSM-5 catalyst to a medium acid point, it is believed that the conversion of propylene to ethylene and the ethylene selectivity are increased.

Specifically, the ZSM-5 catalyst treated with the phosphate compound according to an embodiment of the present invention not only increases the hydrothermal stability of the aluminum in the ZSM-5 catalyst skeleton but also weakens the strong acid point by treating the ZSM-5 catalyst with the phosphate compound. It is expected that some of the strong acid points will be acidic midpoints, increasing the selectivity and conversion of ethylene.

In this respect, the phosphoric acid compound treated in ZSM-5 according to an embodiment of the present invention is preferably phosphoric acid (H 3 PO 4), first ammonium phosphate salt ((NH 4) H 2 PO 4), second ammonium phosphate salt ((NH 4) 2 HPO 4), ( C1-C10) alkyl phosphite and (C1-C10) alkyl phosphate may be one or more than one phosphate compound, more preferably phosphoric acid (H3PO4), the first ammonium phosphate (( NH 4) H 2 PO 4) and diammonium phosphate salt ((NH 4) 2 HPO 4).

Acid-treated ZSM-5 catalyst according to an embodiment of the present invention may be treated with a phosphoric acid compound may be loaded with 0.5 to 5% by weight, preferably 0.75 to 1.5% by weight of phosphorus.

Another aspect of the present invention is to treat the ZSM-5 catalyst, which is a specific zeolite catalyst, with a specific acid to dealuminize the ZSM-5 catalyst to remove the weak acid point so that the ZSM-5 catalyst has controlled weak and strong acidity. By modulating, the acid treated with this ZSM-5 catalyst may be one or two or more selected from ammonium hexafluorosilicate, oxalic acid and ammonium fluoride.

Selective preparation of ethylene from propane according to one embodiment of the present invention is carried out in step b) when the ZSM-5 catalyst is treated with one or more specific acids selected from ammonium hexafluorosilicate, oxalic acid and ammonium fluoride, ZSM It is believed that by dealumination of the -5 catalyst, the weak acid point can be selectively removed to increase the conversion of propylene and to improve the selectivity of ethylene.

In other words, zeolites, including ZSM-5 catalysts, have high electron density and low moiety to show strong acid strength, but the lower the Si / Al ₂ molar ratio, the higher the electron density and the lower the electron density. Therefore, it is difficult to form a strong acid point, so the acidity is high.

In other words, when the density of bridged Si-O-Al in zeolite is high, the weak acidity is increased, whereas when the density of Isolated Si-O-Al is increased, the weak acidity is selectively decreased.

In conclusion, the inventors of the present invention treated ZSM-5 with one or more acids selected from phosphate compounds, ammonium hexafluorosilicates, oxalic acid and ammonium fluoride to control strong acidity and weak acidity from propylene with high conversion and selectivity. It has been found that ethylene can be prepared.

Acid-treated ZSM-5 catalyst according to an embodiment of the present invention is one or two or more acids selected from ammonium hexafluorosilicate, oxalic acid and ammonium fluoride are treated with 0.005 to 0.5 moles, preferably 0.05 to 0.25 moles. Can be.

The selective process for the production of ethylene from propane according to an embodiment of the present invention is very economical to obtain ethylene with surprisingly improved selectivity and simple process, unlike the conventional method, a variety of methods for producing propylene from known ethylene With surprisingly improved conversion and selectivity compared to the process, this method of selectively preparing ethylene from the propane of the present invention can resolve the supply imbalance of ethylene and propylene.

The acid treated ZSM-5 catalyst according to one embodiment of the present invention is preferably ZSM treated with a phosphate compound in terms of producing ethylene with better selectivity and yield from propylene prepared from propane according to one embodiment of the invention. May be -5.

Acid treatment of ZSM-5 according to an embodiment of the present invention may be any method of impregnation that can be recognized by those skilled in the art. Specific examples include ion-exchange method, incipient wetness method, Both solution impregnation methods are applicable.

Hereinafter, the acid treatment of ZSM-5 according to an embodiment of the present invention will be described with an example of using a phosphoric acid compound.

When the phosphoric acid compound is treated on the ZSM-5 catalyst, the position of phosphorus (P) is slightly different depending on the type of phosphoric acid compound. However, in general, the particle size of the phosphoric acid compound is relatively large compared to the pore size of the crystalline zeolite. A relatively large amount of phosphorus (P) is present on the outer surface of the zeolite catalyst because the extent of the compound penetrating into the pores of the crystalline zeolite is smaller than that present on the outer surface of the zeolite.

In the cracking reaction to decompose propylene, Brenstead acid point, which is the strong acid point of ZSM-5 catalyst, is used, and it is assumed that both the outer surface and the inner pore surface of the catalyst exist, and if the reaction occurs at the active point of the outer surface, ZSM- 5 It is believed that this may be a factor to inhibit the shape selectivity of the catalyst, and to reduce the selectivity of the ethylene produced.

Therefore, the method for producing selective ethylene from the propane of the present invention removes the external acid point, which is an external catalyst active point by treating the ZSM-5 catalyst with a phosphate compound, so that the reaction occurs only at the internal acid point of the ZSM-5 catalyst. It is considered to be manufactured.

That is, in the case of the ZSM-5 catalyst treated with such a phosphate compound, the external acid point is appropriately inactivated, so that the reaction mainly occurs at the acid point in the pores of the ZSM-5 catalyst, thereby increasing the selectivity of ethylene.

In addition, the acid-treated ZSM-5 catalyst according to an embodiment of the present invention may have a Si / Al ₂ molar ratio of 23 to 280.

Preferably, the strong acid point by bridged Si-O-Al in the ZSM-5 catalyst is increased to reduce the formation of by-products through excessive hydrocarbon cracking reactions or oligomerization and aromatization of olefins, and acid treated ZSM-5 Si / Al ₂ mole ratio of acid treated ZSM-5 may be in the range of 30 to 100 in terms of not reducing catalyst life due to coke deposition in the catalyst pores, and reducing thermal and hydrothermal stability. In the aspect of increasing the propylene conversion and ethylene selectivity, the Si / Si of ZSM-5 is preferably acid-treated in order to suppress the deterioration of catalytic activity due to the small number of ZSM-5 strong acid points generated due to the smaller silica and neighboring aluminum. The Al ₂ molar ratio may be 30 to 100, more preferably 30 to 80.

ZSM-5 catalyst of the acid-treated ZSM-5 catalyst according to an embodiment of the present invention may be H-ZSM-5, La, Zn, Ni, Fe, Ga, Cu, Pd, Al, Co, M, One or two or more selected from Ce, Cr, Au, Pt, Re, Ru, and Ir may be supported.

A chromium-based or platinum-based catalyst according to an embodiment of the present invention may be any chromium-based catalyst used in the Lummus process or a platinum-based catalyst used in the PDH process, which can be recognized by those skilled in the art. Preferred combinations with 5 catalysts may be Cr ₂ O ₃ / Al ₂ O ₃ or Pt-Sn / Al ₂ O ₃ .

Preferably step b) in the series process of the process for producing selective ethylene from propane according to one embodiment of the present invention is a temperature of 550 to 610 ℃, atmospheric pressure of 1 to 1 MPa, 0.1 to 10 hours ^-1 weight hourly space of propylene And propylene and nitrogen dilution ratios from 1: 0.001 to 0.125.

The specific range of reaction conditions of step b) controlled as described above may produce ethylene with higher selectivity and conversion in combination with the PDH process of step a).

Preferably, the dehydrogenation according to an embodiment of the present invention may be performed at a weight space velocity (WHSV) of 1 to 15 h ^{−1 of the} feedstock including the propane at a reaction temperature of 500 to 610 ° C.

Preferably the method for producing selective ethylene from propane according to an embodiment of the present invention,

a) dehydrogenating a propane-containing feedstock under a chromium-based or platinum-based catalyst to a reaction temperature of 500 to 610 ° C. and a weight space velocity (WHSV) of 1 to 15 h ⁻¹ of the propane-containing feedstock to obtain a propylene-containing mixture; ; And

b) The propylene-containing mixture obtained in the above step is an acid treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst and a temperature of 550-600 ° C., 0.01-1 MPa. And converting the propylene to ethylene by contacting under an atmospheric pressure, 0.1 to 10 hours ^-1 weight hourly space velocity of propylene and propylene and nitrogen dilution ratio conditions of 1: 0.001 to 0.125.

Preferably, in the method for preparing selective ethylene from propane according to one embodiment of the present invention, steps a) and b) may be continuously performed in different reactors in series form.

In the cascade process of the method for preparing selective ethylene from propane according to an embodiment of the present invention, the PDH process and the PTE process are performed in one reactor, preferably, a temperature of 550 to 610 ° C., an air pressure of 0.01 to 1 MPa, It can be carried out at a weight hourly space velocity of propylene of 0.1 to 10 hours ⁻¹ and a propylene and nitrogen dilution ratio of 1: 0.50 to 1.50.

In the method for preparing selective ethylene from propane according to an embodiment of the present invention, the conversion of propane may be 60% or more, the selectivity of ethylene may be 25% or more, and more preferably, the conversion rate of propane is 65% or more. The selectivity can be at least 30%.

The process for selectively producing ethylene from the propane of the present invention has significantly improved conversion and selectivity compared to conventional methods, such as propane cracking and the like.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to examples, but these examples are merely illustrative of the present invention, and the scope of the present invention is not limited only to these examples.

<Measurement of strong acidity, weak acidity and total acidity of catalyst>

The analytical technique used to measure the strong and weak acidity of the catalyst was measured from the acid intensity distribution by NH3-TPD (temperature-programmed desorption), ammonia temperature desorption method.

First, prepare a sample, heat the sample for 60 minutes at 500 ° C, pretreat it, and then adsorb the ammonia at 100 ° C for 30 minutes, and then desorb the ammonia physically adsorbed at 100 ° C for 1 hour to 900 ° C under He gas. Ammonia desorbed by heating at a rate of 5 ° C./min was measured using a TCD detector (thermal conductivity detector). The amount of acid point of the zeolite catalyst was calculated by deconvolution of the measured TPD curve, and the amount of weak acid point and strong acid point was calculated. The total acidity is the sum of the two acidities.

Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to examples, but these examples are merely illustrative of the present invention, and the scope of the present invention is not limited only to these examples.

Example 1 Preparation of ZSM-5 Catalyst Supported with Phosphorus

3 g of ZSM-5 (Zeolyst, Si / Al ₂ = 50, CBV 5524G) was uniformly mixed with an aqueous solution containing 0.43 g of phosphoric acid (H ₃ PO ₄ , 85%), 1.789 g of ethanol and 0.24 g of distilled water, and then dried Solvent was removed. The sample prepared above was calcined at 500 ° C. for 5 hours to prepare a ZSM-5 catalyst having 1% by weight of phosphorus and used in this experiment. The weight of phosphorus supported on the ZSM-5 catalyst was measured by inductively coupled plasma mass spectrometry (ICP-AES, inductively coupled plasma-atomic emission spectroscopy, ICP-AES, Perkin Elmer, Optima 4300 DV).

XRD pattern of the prepared catalyst is shown in Figure 1, it shows the acid point of the catalyst prepared in Table 1 below.

Example 2 Preparation of ZSM-5 Catalyst Treated with 0.1 M Oxalic Acid

1 g of ZSM-5 zeolite (Zeolyst, Si / Al ₂ = 50, CBV 5524G) was added with 20 ml of oxalic acid 0.1M and reacted by heating to reflux for 1 hour at room temperature. After drying for 6 hours using a dry oven, the prepared sample was heated to 60 ℃ per hour and calcined at the final 550 ℃ for 5 hours to prepare a ZSM-5 catalyst treated with 0.1M oxalic acid.

Example 3 Preparation of ZSM-5 Catalyst Treated with 0.1 M Ammonium Fluoride

A ZSM-5 catalyst treated with 0.1M ammonium fluoride was prepared in the same manner as in Example 2, except that in Example 2, the mixture was stirred for 72 hours using ammonium fluoride instead of oxalic acid and calcined at 500 ° C. for 10 hours.

Example 4 Preparation of ZSM-5 Catalyst Treated with 0.1 M Hydrochloric Acid

ZSM- treated with 0.1M hydrochloric acid was carried out in the same manner as in Example 2 except that the reaction was heated to reflux for 4 hours at 85 ° C. for 4 hours using hydrochloric acid instead of oxalic acid, followed by calcination at 400 ° C. for 6 hours. 5 catalysts were prepared.

Example 5 Preparation of ZSM-5 Catalyst Treated with Ammonium Hexafluorosilicate

1 g of ZSM-5 zeolite (Zeolyst, Si / Al ₂ = 50, CBV 5524G) was added to 25 ml of 0.1 M ammonium hexafluorosilicate and reacted by heating to reflux at 90 ° C. for 3 hours. After drying the reaction mixture for 6 hours using a dry oven, the prepared sample was calcined at 500 ℃ for 5 hours to prepare a ZSM-5 catalyst treated with 0.1M ammonium hexafluorosilicate, used in this experiment. .

The XRD pattern of the prepared catalyst is shown in FIG. 1, and Table 1 shows the acid point by NH3-TPD analysis of the catalysts prepared in Examples 1 and 5.

catalyst Weak acidity Strong acidity Strong acidity / weak acidity Total acidity Example 1 ZSM-5 with 1% by weight phosphorus 0.105 0.273 2.61 0.378 Example 5 ZSM-5 Treated with 0.1M AHFS 0.049 0.385 0.142 0.434 Comparative Example 1 H-ZSM-5 0.140 0.450 3.21 0.590

Example 6 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphorus with Temperature by Cascade Method

The PDH catalyst Cr ₂ O ₃ / Al ₂ O ₃ was prepared according to the method of (Applied Catalysis A: General 233 (2002) 21--33) and used in the present invention.

Cr ₂ O ₃ / Al ₂ O in a stainless reactor with a quartz reactor pretreated for 3 hours with 550 ^° C. nitrogen gas (50 ml / min) as shown in FIG. 2 (left) for the production of selective ethylene from propane. ₃ is a reaction while the propane gas is injected as in example 1, 0.5g of the catalyst was charged 0.5g reaction of propane gas (Rigas (purity99.99%), 5.04 ml / min) continuously pass through the catalyst layer in the reactor It was made to proceed. 0.1 MPa, nitrogen loading was 5.04ml / min, the weight space velocity (WHSV) of the reactants was maintained at 1.2h ^-1 , the reaction temperature was carried out at 550 ℃. The product produced after the reaction was analyzed by gas chromatography, and the conversion of propane, selectivity and yield of ethylene according to the reaction time of each catalyst were calculated, and the results are shown in FIG. 3.

Cov. C _{3 =} denote conversion of C _{3 =} ; Wt _{C3 =} to represents the weight of Propane at the initial time; WT C _{3 =} is the weight of C _{3 =} at the desired reaction time; Selec. C _{2 =} denote the selectivity of product C _{2 =} ; WT _{C2 =} is the weight of product C _{2 =} ;

Comparative Example 1 Preparation of Ethylene from Propane

Except for using the PTE catalyst in Example 6 in Example 6 except that only the dehydrogenation process was carried out in the same manner as in Example 6 shown in Figure 3 the results.

Comparative Example 2 Preparation of Ethylene from Propane

Except that the PTE process using only the PDH catalyst Cr ₂ O ₃ / Al ₂ O ₃ in Example 6 was prepared in the same manner as in Example 6 and the results are shown in FIG.

Example 7 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphorus with Temperature in Example 6

In Example 6, the reaction temperature was maintained in the same manner as in Example 6 except that the reaction temperature was changed to 500 ° C., 580 ° C., and 610 ° C., and ethylene was prepared from propane, and the results are shown in FIG. 4.

As shown in FIG. 4, the best propane conversion and ethylene selectivity were shown at 550-610 ° C.

Example 8 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphorus with Temperature by Series Method

After the model feed from the PDH trailing gas was prepared in the composition shown in Table 2 below, 0.5 g of the catalyst of Example 1 was charged into a fixed bed reactor of laboratory specifications using a quartz reactor as shown in FIG. 2 (right). Injecting a gas having a composition as shown in Table 2 so that the reaction proceeds while the propylene gas passes through the catalyst layer in the reactor. 0.1 MPa, nitrogen loading was 5.04ml / min, the weight space velocity (WHSV) of the reactants was maintained at 1.2h ^-1 , the reaction temperature was carried out at 550 ℃.

The product produced after the reaction was analyzed by gas chromatography, and the conversion rate of propane, selectivity and yield of ethylene were calculated according to the reaction time of each catalyst. Here, the conversion rate, ethylene selectivity and yield of propane were calculated according to the following equations (1) to (2).

Components in model feed Formula Compositions (wt%) Hydrogen H ₂ 2.01 Ethane C ₂ H ₄ 1.04 Propane C ₃ H ₈ 37.06 Propylene C ₃ H ₆ 51.68

Example 9 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphorus with Temperature in Example 8

In Example 8, the reaction temperature was maintained in the same manner as in Example 8 except that the reaction temperature was changed to 500 ° C., 550 ° C., 580 ° C., and 610 ° C., and ethylene was prepared from propane, and the results are shown in FIG. 5. It was.

As shown in FIG. 5, the best propane conversion and ethylene selectivity were shown at 550-610 ° C.

Example 10 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphor According to Space Velocity in Example 8

In Example 8, the reaction temperature was maintained in the same manner as in Example 8, except that the weight space velocity (WHSV) of the reactants was changed to (1.2, 5, 8.5. 12, 15) h ⁻¹ . Ethylene was prepared from propane, and the results are shown in FIG. 6.

As shown in FIG. 6, the best propane conversion and ethylene selectivity were shown at 5 to 10 h ⁻¹ .

Example 11 Preparation of Ethylene from Propane Under ZSM-5 Catalyst Supported by Phosphorus at Partial Pressure in Example 8

In Example 8, ethylene was prepared from propane in the same manner as in Example 8 except that the reaction temperature was changed to 550 ° C. and partial pressure as shown in FIG. 7 (0.0077 to 0.0500), and the result is illustrated in FIG. 7. Indicated.

As shown in FIG. 7, it can be seen that the conversion rate of propylene and the selectivity of ethylene are clearly different according to the dilution ratio of propylene and nitrogen, and the dilution ratio of nitrogen and propylene is more excellent at 1: 0.001 to 0.030. It can be seen that it appears.

Specifically, when the injection amount of propane is fixed at 29 ml / min, the nitrogen injection amount is in the range of 1 to 10 ml / min, that is, the dilution ratio of nitrogen and propylene is 1: 0.001 to 0.125, preferably 1: 0.025 to 0.10, more preferably 1: It can be seen that better conversion and selectivity appear between 0.025 and 0.075.

Example 12 Preparation of Ethylene from Propane

In Example 8, except that the catalyst prepared in Example 6 was used instead of the catalyst prepared in Example 1 was prepared in the same manner as in Example 8 and the results are shown in FIG.

Comparative Example 3 Preparation of Ethylene from Propane

In Example 9, except that the H-ZSM-5 catalyst instead of the catalyst prepared in Example 1 was prepared in the same manner as in Example 9 and the results are shown in FIG.

In the present invention as described above has been described by specific embodiments and limited embodiments and drawings, but this is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, the present invention Those skilled in the art can make various modifications and variations from this description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later belong to the scope of the present invention. .

Claims (13)

a) dehydrogenating a feedstock comprising propane under a chromium-based or platinum-based catalyst to obtain a propylene-containing mixture; And
b) contacting the propylene-containing mixture obtained in the above step with an acid treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst or less to convert propylene into ethylene. Method for producing selective ethylene from propane containing. Chromium-based or platinum-based catalysts; And an acid-treated ZSM-5 catalyst having a weak acidity of 0.145 mmol / g-catalyst and a strong acidity of 0.410 mmol / g-catalyst or less; adding a feedstock including propane to the reactor including the propane; Contacting a feedstock with the chromium-based or platinum-based catalyst and the acid treated ZSM-5 catalyst to produce ethylene from propane. The method according to claim 1 or 2,
The acid-treated ZSM-5 catalyst is treated with a phosphoric acid compound to support 0.5 to 5% by weight of phosphorus is a method for producing selective ethylene from propane. The method of claim 3, wherein
Wherein said phosphate compound is one or more selected from propane selected from phosphoric acid, ammonium monophosphate, diammonium phosphate, (C1-C10) alkylphosphorous acid and (C1-C10) alkylphosphate. The method according to claim 1 or 2,
Wherein said acid treated ZSM-5 catalyst is treated with one or more acids selected from hydrochloric acid, ammonium hexafluorosilicate, oxalic acid and ammonium fluoride. The method of claim 5,
Wherein said acid treated ZSM-5 catalyst is treated with 0.005 to 0.5 moles of acid. The method according to claim 1 or 2,
The weak acidity is 0.040 to 0.110 mmol / g-catalyst and the strong acidity is 0.200 to 0.410 mmol / g-catalyst. The method according to claim 1 or 2,
The acid-treated ZSM-5 catalyst has a strong acidity / weak acidity of 0.10 to 8.0 method of producing selective ethylene from propane. The method according to claim 1 or 2,
The acid-treated ZSM-5 catalyst is a method for producing selective ethylene from propane having a Si / Al ₂ molar ratio of 23 to 280. The method of claim 1,
Step b) is an optional ethylene from propane carried out at a temperature of 550 to 610 ° C., a pressure of 0.01 to 1 MPa, an hourly space velocity of propylene of 0.1 to 10 hours ⁻¹ and a propylene and nitrogen dilution ratio of 1: 0.001 to 0.125 Manufacturing method. The method of claim 2,
The step is the preparation of selective ethylene from propane carried out at a temperature of 550-610 ° C., a pressure of 0.01-1 MPa, an hourly space velocity of propylene of 0.1-10 hours ⁻¹ and a propylene-nitrogen dilution ratio of 1: 0.5-1.5. Way. The method according to claim 1 or 2,
The chromium catalyst is Cr ₂ O ₃ / Al ₂ O ₃ phosphorus, the platinum catalyst is Pt-Sn / Al ₂ O ₃ phosphorus Process for the production of selective ethylene from propane. The method of claim 1,
The dehydrogenation is a method for producing selective ethylene from propane, characterized in that carried out at a reaction temperature of 500 to 610 ° C at a weight space velocity (WHSV) of 1 to 15 h ^-1 conditions of the feedstock containing the propane.

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