A catalyst for producing polymethylaromatic hydrocarbons from heavy aromatic hydrocarbons, and a preparation method and application thereof

Abstract

The present application relates to the preparation technical field of heavy aromatic lightening catalyst, especially relates to a heavy aromatic lightening production polymethylbenzene catalyst and its preparation method and application. The catalyst takes HZSM-5 as a carrier, and loads bimetallic oxide La-X-MMO as an active component; wherein the metal X is one of Mg, Zn and Cu; the mass ratio of the metal La and the carrier is 5%-8%:1; the mass ratio of the metal X and the carrier is 0.4%-4%. The present application provides a catalyst with various non-noble metal oxides as active components, which has high catalytic activity and selectivity, the single-pass conversion rate reaches more than 80%, the light aromatic hydrocarbon (benzene, toluene, xylene) yield reaches more than 75%, and through the heavy aromatic lightening reaction evaluation, the catalyst provided by the present application still has good catalytic activity and selectivity after 300h of evaluation, and has long catalytic life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of preparation of heavy aromatic hydrocarbon lightening catalyst, in particular to a heavy aromatic hydrocarbon lightening catalyst for producing polymethyl aromatic hydrocarbon and a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission or a recognition that the information forms part of the prior art that is already known in any country in the world.

[0003] At present, C9 + The utilization rate of heavy aromatic hydrocarbon is low, and most of it is burned as inferior fuel except a small amount used as solvent. C9 + This low-quality utilization of heavy aromatic hydrocarbon not only wastes resources, but also causes great harm to the natural environment and the health of animals, plants and human bodies. At the same time, benzene, toluene and xylene are important organic chemical raw materials next only to ethylene and propylene. Therefore, how to utilize these heavy aromatic hydrocarbon resources in a high-quality way and convert them into polymethyl aromatic hydrocarbon products has become one of the important topics in the field of aromatic hydrocarbon technology at home and abroad.

[0004] The existing heavy aromatic hydrocarbon lightening methods include thermal hydrodealkylation, catalytic hydrodealkylation and catalytic hydrocracking. Among them, the thermal hydrodealkylation method has a high reaction temperature, generally 700-800℃, so it has high requirements for the material of the reactor and high energy consumption, and therefore the utilization rate of this method is low. The catalytic hydrodealkylation and catalytic hydrocracking methods are the most commonly used methods, and they have high reactivity and selectivity of light aromatic hydrocarbons (benzene, toluene and xylene). However, the key to these two methods is the development of high-efficiency catalysts and catalytic processes. At present, the catalysts mainly use molecular sieves as carriers and load noble metals as active components, while the catalysts with cheap metals or metal oxides as active components have low catalytic activity, so the catalytic cost of the current catalysts is high. At the same time, when the catalysts with noble metals as active components in the existing technology are used for catalytic reaction, the temperature of the catalytic reaction is high, the yield of polymethyl aromatic hydrocarbon is low, and the service life of the catalyst is short. SUMMARY

[0005] In order to overcome the above problems, the present application provides a heavy aromatic hydrocarbon lightening catalyst for producing polymethyl aromatic hydrocarbon and a preparation method and application thereof. A catalyst with multiple non-noble metal oxides as active components is provided, which has high catalytic activity and selectivity and long catalytic service life.

[0006] To achieve the above technical purposes, the present application adopts the following technical solutions:

[0007] The first aspect of the present application provides a catalyst for producing polymethyl aromatic hydrocarbons by heavy aromatic hydrocarbon lightening, which is characterized in that the catalyst is prepared by loading bimetallic oxide La-X-MMO as an active component on HZSM-5 as a carrier; wherein metal X is one of Mg, Zn and Cu.

[0008] The mass ratio of metal La to the carrier is 5%-8%:1; and the mass ratio of metal X to the carrier is 0.4%-4%:1.

[0009] The second aspect of the present application provides a preparation method of the catalyst for producing polymethyl aromatic hydrocarbons by heavy aromatic hydrocarbon lightening, which comprises the following steps:

[0010] The catalyst for producing polymethyl aromatic hydrocarbons by heavy aromatic hydrocarbon lightening is prepared by adding lanthanum nitrate and metal X nitrate into a dilute aqueous ammonia solution, adding the HZSM-5 carrier into the mixed solution after the reaction is completed, and then performing water removal and drying after standing, and finally calcining.

[0011] The third aspect of the present application provides a method for producing polymethyl aromatic hydrocarbons by heavy aromatic hydrocarbon lightening, which comprises: allowing C9A or C10A heavy aromatic hydrocarbons with ethyl and propyl groups to react with methanol under the catalysis of a catalyst to obtain benzene, toluene and xylene, wherein the catalyst is the catalyst of the first aspect or the catalyst prepared by the preparation method of the second aspect.

[0012] The present application has the following beneficial effects:

[0013] (1) The present application provides a catalyst with various non-noble metal oxides as active components, which has high catalytic activity and selectivity, and the single-pass conversion rate is more than 80%, and the yield of light aromatic hydrocarbons (benzene, toluene and xylene) is more than 75%. In addition, through the evaluation of heavy aromatic hydrocarbon lightening reaction, the catalyst provided by the present application still has good catalytic activity and selectivity after 300 hours of evaluation, and has a long catalytic life.

[0014] (2) The main reaction of heavy aromatic hydrocarbon lightening is dealkylation, for example, ethylbenzene, diethylbenzene or methylethylbenzene contained in heavy aromatic hydrocarbons will lose ethyl groups, and n-propylbenzene, isopropylbenzene or methylpropylbenzene will lose propyl groups to generate benzene, toluene and xylene. The zeolite catalyst loaded with metal shows excellent activity, selectivity and stability in the dealkylation of heavy aromatic hydrocarbons. In addition, the rare earth metal lanthanum shows good catalytic activity in the process of heavy aromatic hydrocarbon lightening, and the coordination interaction between La and other metals can improve the effect of heavy aromatic hydrocarbon lightening. By using the catalyst of the present application, the production cost of the catalyst can be reduced, the utilization efficiency of heavy aromatic hydrocarbons can be improved, and the production and efficiency of enterprises can be increased. DETAILED DESCRIPTION

[0015] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0016] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0017] In a first exemplary embodiment of the present application, a catalyst for producing polymethylaromatic hydrocarbons from heavy aromatic hydrocarbons is provided, which comprises HZSM-5 as a carrier and a bimetallic oxide La-X-MMO as an active component; wherein the metal X is one of Mg, Zn and Cu.

[0018] The mass ratio of the metal La to the carrier is 5% to 8%: 1, and the mass ratio of the metal X to the carrier is 0.4% to 4%: 1.

[0019] In one or more embodiments, when the metal X is Mg, the mass ratio of the metal Mg to the carrier is 0.4% to 1.40%, preferably 0.86% to 1.40%.

[0020] In one or more embodiments, when the metal X is Zn, the mass ratio of the metal Zn to the carrier is 1.16% to 3.80%, preferably 2.33% to 3.80%.

[0021] In one or more embodiments, when the metal X is Cu, the mass ratio of the metal Cu to the carrier is 1.15% to 3.72%, preferably 2.30% to 3.72%.

[0022] In a second exemplary embodiment of the present application, a preparation method of the catalyst for producing polymethylaromatic hydrocarbons from heavy aromatic hydrocarbons is provided, which comprises the following steps:

[0023] The lanthanum nitrate and the metal X nitrate are added to a dilute aqueous ammonia solution, and after the reaction is completed, the HZSM-5 carrier is added to the mixed solution, and after standing, water is removed and dried, and then calcined to obtain the catalyst for producing polymethylaromatic hydrocarbons from heavy aromatic hydrocarbons.

[0024] In one or more embodiments, the molar ratio of the lanthanum nitrate and the metal X nitrate is 1:0.5 to 1.

[0025] In one or more embodiments, the concentration of the dilute aqueous ammonia is 0.1-0.3 mol / L, preferably 0.2 mol / L.

[0026] In one or more embodiments, the mass ratio of the lanthanum nitrate to the HZSM-5 carrier is 15.5-25:100.

[0027] In one or more embodiments, the reaction time is 1-2 h, preferably 1 h.

[0028] In one or more embodiments, the standing time is 1.5-3 h, preferably 2 h.

[0029] In one or more embodiments, the calcination temperature is 500-600℃, preferably 550℃.

[0030] In one or more embodiments, the calcination time is 2-4 h, preferably 2 h.

[0031] In a third typical embodiment of the present application, a method for producing polymethylaromatic hydrocarbons from heavy aromatic hydrocarbons is provided, which comprises: reacting C9A or C10A heavy aromatic hydrocarbons with ethyl and propyl groups with methanol under the catalysis of a catalyst to obtain benzene, toluene and xylene, wherein the catalyst is the catalyst of the first aspect or the catalyst prepared by the preparation method of the second aspect.

[0032] In one or more embodiments, the C9A or C10A heavy aromatic hydrocarbons with ethyl and propyl groups include p-methyl ethylbenzene, propylbenzene, 2,4-dimethyl ethylbenzene and p-methyl propylbenzene, preferably 2,4-dimethyl ethylbenzene.

[0033] In one or more embodiments, the molar ratio of the C9A or C10A heavy aromatic hydrocarbons with ethyl and propyl groups to methanol is 1:2-4.

[0034] In one or more embodiments, the reaction conditions are as follows: the reaction pressure is 0.8-1.2 MPa, the reaction temperature is 320-350℃, and the space velocity of the raw material C9A or C10A heavy aromatic hydrocarbons with ethyl and propyl groups to methanol is 0.5-1 h -1 .

[0035] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific examples.

[0036] The catalyst carrier HZSM-5 in the embodiments of the present application is purchased from Zibo Qixin Innovation Material Technology Co., Ltd., and the silicon-aluminum ratio is 60.

[0037] Example 1

[0038] 15.59 g of lanthanum nitrate hexahydrate and 9.21 g of magnesium nitrate hexahydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution after standing for 2 h, drying at 120°C for 2 h, and calcining at 550°C for 2 h, to obtain a catalyst A1 for producing polymethylaromatics by lightening heavy aromatics.

[0039] Example 2

[0040] 15.59 g of lanthanum nitrate hexahydrate and 11.29 g of zinc nitrate hexahydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution after standing for 2 h, drying at 120°C for 2 h, and calcining at 550°C for 2 h, to obtain a catalyst A2 for producing polymethylaromatics by lightening heavy aromatics.

[0041] Example 3

[0042] 15.59 g of lanthanum nitrate hexahydrate and 9.20 g of copper nitrate trihydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution after standing for 2 h, drying at 120°C for 2 h, and calcining at 550°C for 2 h, to obtain a catalyst A3 for producing polymethylaromatics by lightening heavy aromatics.

[0043] Experimental Example 1

[0044] A fixed bed reactor was used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the reaction conditions were as follows: the reaction pressure was 0.8 MPa, the reaction temperature was 340°C, the space velocity of the raw material 2,4-dimethyl ethylbenzene and methanol was 0.5 h -1 , and the molar ratio of 2,4-dimethyl ethylbenzene to methanol was 1:3. Catalysts A1, A2 and A3 prepared in Examples 1-3 were used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the catalytic effects were shown in Table 1.

[0045] Table 1 Catalytic effects of catalysts A1, A2 and A3

[0046]

[0047] Example 4

[0048] La(NO3)3.6H2O 18.71g, Mg(NO3)2.6H2O 9.21g were added into 90ml of 0.2mol / L dilute aqueous ammonia solution, after the reaction was completed, 100g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 would completely adsorb the above-mentioned mixed solution, and then the catalyst carrier was dried at 120°C for 2h, and calcined at 550°C for 2h, to obtain the catalyst B1 for producing polymethylaromatics by lightening heavy aromatics.

[0049] Example 5

[0050] La(NO3)3.6H2O 21.83g, Mg(NO3)2.6H2O 9.21g were added into 90ml of 0.2mol / L dilute aqueous ammonia solution, after the reaction was completed, 100g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 would completely adsorb the above-mentioned mixed solution, and then the catalyst carrier was dried at 120°C for 2h, and calcined at 550°C for 2h, to obtain the catalyst B2 for producing polymethylaromatics by lightening heavy aromatics.

[0051] Example 6

[0052] La(NO3)3.6H2O 24.95g, Mg(NO3)2.6H2O 9.21g were added into 90ml of 0.2mol / L dilute aqueous ammonia solution, after the reaction was completed, 100g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 would completely adsorb the above-mentioned mixed solution, and then the catalyst carrier was dried at 120°C for 2h, and calcined at 550°C for 2h, to obtain the catalyst B3 for producing polymethylaromatics by lightening heavy aromatics.

[0053] Experimental Example 2

[0054] The fixed bed reactor was used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the reaction conditions were as follows: the reaction pressure was 0.8MPa, the reaction temperature was 340°C, the space velocity of 2,4-dimethyl ethylbenzene and methanol was 0.5h-1, the molar ratio of 2,4-dimethyl ethylbenzene and methanol was 1:3, and the catalysts B1, B2 and B3 prepared in Examples 4-6 were used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the catalytic effects were shown in Table 2. -1

[0055] Table 2 Catalytic effects of catalysts B1, B2 and B3

[0056]

[0057]

[0058] Experimental Example 7

[0059] ​15.59 g of lanthanum nitrate hexahydrate and 4.61 g of magnesium nitrate hexahydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution, and was dried at 120°C for 2 h and calcined at 550°C for 2 h to obtain a catalyst C1 for producing polymethylaromatics by lightening heavy aromatics.

[0060] Experimental Example 8

[0061] 15.59 g of lanthanum nitrate hexahydrate and 5.99 g of magnesium nitrate hexahydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution, and was dried at 120°C for 2 h and calcined at 550°C for 2 h to obtain a catalyst C2 for producing polymethylaromatics by lightening heavy aromatics.

[0062] Experimental Example 9

[0063] 15.59 g of lanthanum nitrate hexahydrate and 7.37 g of magnesium nitrate hexahydrate were added to 90 mL of 0.2 mol / L dilute aqueous ammonia solution, after the reaction was completed, 100 g of catalyst carrier HZSM-5 was added, and the catalyst carrier HZSM-5 completely adsorbed the above-mentioned mixed solution, and was dried at 120°C for 2 h and calcined at 550°C for 2 h to obtain a catalyst C3 for producing polymethylaromatics by lightening heavy aromatics.

[0064] Experimental Example 3

[0065] The fixed bed reactor was used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the reaction conditions were as follows: the reaction pressure was 0.8 MPa, the reaction temperature was 340°C, the space velocity of 2,4-dimethyl ethylbenzene and methanol was 0.5 h -1 , the molar ratio of 2,4-dimethyl ethylbenzene and methanol was 1:3, and the catalysts C1, C2 and C3 prepared in Examples 4 to 6 were used to catalyze the production of polymethylaromatics by lightening heavy aromatics, and the catalytic effects were shown in Table 3.

[0066] Table 3 Catalytic effects of catalysts C1, C2 and C3

[0067]

[0068] Experimental Example 4

[0069] The fixed bed reactor was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, wherein the reaction conditions were as follows: the reaction pressure was 1 MPa, 1.1 MPa and 1.2 MPa respectively, the reaction temperature was 340 ℃, the space velocity of raw material 2,4-dimethyl ethyl benzene and methanol was 0.5 h -1 , the molar ratio of 2,4-dimethyl ethyl benzene and methanol was 1:3, and the catalyst A1 prepared in Example 1 was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, and the catalytic effect was shown in Table 4.

[0070] Table 4 Catalytic effect of heavy aromatic hydrocarbon lightening under different pressures

[0071]

[0072] Experimental Example 5

[0073] The fixed bed reactor was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, wherein the reaction conditions were as follows: the reaction pressure was 0.8 MPa, the reaction temperature was 320 ℃, 350 ℃ and 360 ℃ respectively, the space velocity of raw material 2,4-dimethyl ethyl benzene and methanol was 0.5 h -1 , the molar ratio of 2,4-dimethyl ethyl benzene and methanol was 1:3, and the catalyst A1 prepared in Example 1 was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, and the catalytic effect was shown in Table 5.

[0074] Table 5 Catalytic effect of heavy aromatic hydrocarbon lightening under different temperature conditions

[0075]

[0076] Experimental Example 6

[0077] The fixed bed reactor was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, wherein the reaction conditions were as follows: the reaction pressure was 0.8 MPa, the reaction temperature was 340 ℃, the space velocity of raw material 2,4-dimethyl ethyl benzene and methanol was 0.5 h -1 , the molar ratio of 2,4-dimethyl ethyl benzene and methanol was 1:2 and 1:4 respectively, and the catalyst A1 prepared in Example 1 was used to catalyze heavy aromatic hydrocarbon lightening to produce polymethyl aromatic hydrocarbon, and the catalytic effect was shown in Table 6.

[0078] Table 6 Catalytic effect of heavy aromatic hydrocarbon lightening under different raw material molar ratios

[0079]

[0080] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing polymethyl aromatics by lightening heavy aromatics, characterized in that, include: C9A or C10A heavy aromatics containing ethyl or propyl groups react with methanol under the catalysis of a catalyst to produce benzene, toluene, and xylene. The catalyst is a catalyst for the lightening of heavy aromatics to produce polymethyl aromatics. The catalyst uses HZSM-5 as a support and supports a bimetallic oxide La-X-MMO as the active component. Metal X is one of Mg, Zn, and Cu; The mass ratio of metal La to the support is 5%~8%:1; the mass ratio of metal X to the support is 0.4%~4%:

1. The catalyst preparation method includes: adding lanthanum nitrate and nitrate of metal X to a dilute ammonia solution; after the reaction is completed, adding HZSM-5 support to the mixed solution; allowing it to stand and then drying it after dehydration; and calcining it to obtain a catalyst for the production of polymethyl aromatics from heavy aromatics.

2. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, When the metal X is Mg, the mass ratio of Mg to the support is 0.4%~1.40%.

3. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 2, characterized in that, The mass ratio of metallic Mg to the support is 0.86%~1.40%.

4. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, When the metal X is Zn, the mass ratio of metal Zn to the carrier is 1.16%~3.80%; Alternatively, when the metal X is Cu, the mass ratio of metal Cu to the carrier is 1.15% to 3.72%.

5. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 4, characterized in that, The mass ratio of metallic Zn to the support is 2.33%~3.80%.

6. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 4, characterized in that, The mass ratio of metallic Cu to the support is 2.30% to 3.72%.

7. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, The molar ratio of lanthanum nitrate to nitrate of metal X is 1:0.5~1; Alternatively, the concentration of the dilute ammonia solution is 0.1~0.3 mol / L; The mass ratio of lanthanum nitrate to HZSM-5 support is 15.5~25:

100.

8. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 7, characterized in that, The concentration of the dilute ammonia solution is 0.2 mol / L.

9. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, The reaction time is 1-2 hours; Alternatively, the settling time is 1.5 to 3 hours.

10. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 9, characterized in that, The reaction time is 1 hour.

11. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 9, characterized in that, The settling time is 2 hours.

12. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, The calcination temperature is 500~600℃; Alternatively, the calcination time is 2-4 hours.

13. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 12, characterized in that, The calcination temperature is 550℃.

14. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 12, characterized in that, The calcination time is 2 hours.

15. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, The ethyl or propyl C9A or C10A heavy aromatic hydrocarbons include p-methylethylbenzene, propenylbenzene, 2,4-dimethylethylbenzene and p-methylpropenylbenzene; Alternatively, the molar ratio of C9A or C10A heavy aromatics containing ethyl or propyl groups to methanol is 1:2 to 4.

16. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 15, characterized in that, The heavy aromatic hydrocarbon is 2,4-dimethylethylbenzene.

17. The method for producing polymethyl aromatics by lightening heavy aromatics as described in claim 1, characterized in that, The reaction conditions for the production of polymethyl aromatics from heavy aromatics are as follows: reaction pressure of 0.8~1.2 MPa, reaction temperature of 320~350℃, and a space velocity of 0.5~1 h⁻¹ for the C9A or C10A heavy aromatics containing ethyl or propyl groups and methanol. -1 .

Images