Synergistic catalyst for coking crude benzene hydrofining as well as preparation method and application thereof

Abstract

The invention discloses a synergistic catalyst for coking crude benzene hydrofining, a preparation method of the synergistic catalyst and a method for hydrofining coking crude benzene by using the synergistic catalyst. The synergistic catalyst is formed by filling a reactor with a synergistic catalyst Z1 and a synergistic catalyst Z2 in a layered manner according to a specific mass ratio, in the reactor, the synergistic catalyst Z1 is arranged on the upper layer of the synergistic catalyst Z2, the filling mass fraction of the synergistic catalyst Z1 is 10-24%, and the filling mass fraction of the synergistic catalyst Z2 is 76-90%. The catalyst has good selectivity, catalytic activity and stability and long cycle life under the coking crude benzene two-step hydrogenation process condition. By using the catalyst, impurities such as silicon, chlorine, sulfur, nitrogen and the like in crude benzene can be effectively removed, meanwhile, carbon deposition is reduced, the service life of the catalyst is greatly prolonged, the yield of pure benzene cannot be reduced by excessive hydrogenation, and long-period stable operation of equipment is met.

Description

Technical Field

[0001] The present invention relates to the field of hydrorefining of coking crude benzene, and in particular to a synergistic catalyst for hydrorefining of coking crude benzene, a preparation method thereof, and a method for hydrorefining of coking crude benzene using the synergistic catalyst. The synergistic catalyst can not only realize hydrorefining of coking crude benzene, but also realize desiliconization and dechlorination treatment of coking crude benzene. Background Art

[0002] During the process of preparing coke by high-temperature dry distillation of coal, many by-products such as coal gas, tar, ammonia, and crude benzene are produced. Taking coking crude benzene as raw material, harmful substances such as sulfur and nitrogen are removed through physical or chemical methods to obtain high-purity benzene, toluene, xylene, etc. that can be used as raw materials. The silicon content in coking crude benzene is generally low, so the desiliconization of coking crude benzene is rarely considered in the refining process of coking crude benzene. However, with the increasing deterioration of raw materials in recent years, the impurities in the coking crude benzene raw material contain not only the main sulfides such as thiophene and carbon disulfide and organic nitrogen compounds, but also impurities such as organic chlorine and organic silicon. Among them, organic silicon mainly exists in the form of cyclosiloxane, silane or silanol, containing SiOH, Si(OH) 2 、SiOHCH 3 、Si(CH 3 ) 2 The analysis shows that hexamethylcyclotrisiloxane is the main component of organosilicon. During the hydrogenation process, organochlorine reacts chemically under high temperature, high pressure and hydrogen to produce hydrogen chloride, causing serious corrosion of the equipment. Under hydrogenation reaction conditions, organosilicon generates small molecular silicides that are deposited on the surface of the hydrogenation catalyst, causing permanent poisoning and inactivation of the catalyst. At the same time, coking crude benzene contains a small amount of unsaturated substances such as olefins, dienes and indene, which can easily lead to coking and inactivation of the hydrogenation catalyst.

[0003] CN104492450B discloses a method for preparing a gasoline desiliconization catalyst. The catalyst is made of Al 2 O 3 -TiO 2 -B 2 O 3 The composite oxide is used as the carrier, Ni-Mo-W-Ce is used as the active component, and it is calcined in a water vapor atmosphere. It has a specific pore size and a large pore volume, and can effectively adsorb and remove impurity silicon, and can remove silicon in gasoline from 197ppm to less than 1ppm. Although the catalyst has a significant desiliconization effect, since gasoline does not contain chlorine, it has not been proven whether the carrier will be corroded in the presence of chlorine, and it cannot be used for desiliconization and dechlorination of coking crude benzene.

[0004] CN1478862A discloses a method for removing organic silicon compounds from silicon-containing fractions. Through an adsorbent bed containing pseudo-boehmite and silicon oxide, part of the silicon can be removed to about 10 ppm, but it is difficult to further reduce it. The adsorption and desorption process is long, and the γ-Al 2 O 3 It is sensitive to high Cl, which will damage the catalyst structure and cause loss of active components. The catalyst is also not suitable for dechlorination and desiliconization of coking crude benzene.

[0005] CN103611566A discloses a catalyst for removing organic chlorine from high-chlorine oil products and a preparation method thereof. First, a molecular sieve containing an auxiliary agent P-MgAl 2 O 4 -Al 2 O 3 The composite carrier is then impregnated with water-soluble compounds of active components Ni or Co and Mo, W and Ce, and then dried and calcined to form a hydrodechlorination catalyst. The catalyst has good activity and stability. At 240°C, it can remove organic chlorides from oil products with a removal rate of more than 99%. However, the catalyst test cycle is short and it cannot prove whether silicon deposition deactivates the catalyst. At the same time, the reaction temperature is low, which will cause unsaturated olefins to carbonize on the catalyst surface and affect the catalyst life.

[0006] Therefore, in response to the problems currently faced by the coking crude benzene refining process, it is still necessary to develop new hydrogenation catalysts that are required to have the ability to remove impurities such as silicon, chlorine, sulfur, and nitrogen, while effectively preventing carbon deposition and ensuring the long-term stable operation of the hydrogenation unit. Summary of the invention

[0007] In view of the problems existing in the prior art, the object of the present invention is to provide a synergistic catalyst for removing impurities such as organosilicon, organochlorine, thiophene sulfur and organic nitrogen from coking crude benzene, a preparation method thereof and a method for hydrogenating and refining coking crude benzene using the catalyst. The catalyst has good selectivity, catalytic activity, stability and long cycle life under the two-step hydrogenation process conditions of coking crude benzene. The use of the catalyst can effectively remove impurities such as silicon, chlorine, sulfur and nitrogen from crude benzene, while reducing the occurrence of carbon deposition, greatly extending the life of the catalyst, and will not excessively hydrogenate to reduce the yield of pure benzene, so as to meet the long-term stable operation of the equipment.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A synergistic catalyst for hydrorefining of coking crude benzene, the synergistic catalyst is composed of synergistic catalyst Z1 and synergistic catalyst Z2 loaded in layers in a reactor according to a specific mass ratio, wherein synergistic catalyst Z1 has the function of removing organic silicon impurities, and synergistic catalyst Z2 has the function of removing impurities such as chlorine, sulfur, and nitrogen.

[0010] In the reactor, the synergistic catalyst Z1 is placed on the upper layer of the synergistic catalyst Z2, the loading mass fraction of the synergistic catalyst Z1 is 10%-24%, and the loading mass fraction of the synergistic catalyst Z2 is 76%-90%. Preferably, the loading mass fraction of the synergistic catalyst Z1 is 14%-18%, and the loading mass fraction of the synergistic catalyst Z2 is 82%-86%. When the mass fractions of the two catalysts are within the above range, they have a good synergistic effect. Outside the mass fraction range, or omitting or replacing any one component, the expected synergistic effect cannot be achieved.

[0011] The synergistic catalyst Z1 is prepared from magnesium-aluminum spinel that has been hydrothermally treated with a hydroxyl auxiliary agent.

[0012] Preferably, Al in the magnesium-aluminum spinel 2 O 3 The mass ratio of magnesium to MgO is (74-86): (26-14), and the specific surface area is 400-550m 2 / g, pore volume is 1.2-1.5ml / g, preferably, Al in magnesium aluminum spinel 2 O 3 The mass ratio of Al:MgO is (78-82):(22-18). 2 O 3 The Al species is hexacoordinated AlO with an octahedral structure. 6 , alumina with other crystal structures cannot achieve the expected desiliconization effect.

[0013] Preferably, the hydroxy auxiliary agent is selected from glycerol monomethyl ether, propylene glycol and butylene glycol, preferably glycerol monomethyl ether.

[0014] Preferably, the heat treatment conditions of the hydroxyl auxiliary agent are as follows: 15g-25g of magnesium aluminum spinel and 100ml-200ml of glycerol monomethyl ether solution are added into the reactor at a concentration of 0.1-0.5mol / L, the reaction temperature is 205-220°C, the reactor speed is 100r / min, and the time is 2.5h. Then the mixture is cooled and depressurized and dried to constant weight.

[0015] The synergistic catalyst Z2 is a supported catalyst, with a composite oxide Al 2 O 3 -TiO 2 The catalyst Z2 was prepared by sequentially impregnating the auxiliary agent and the active component Co and Mo precursor solutions with the catalyst as the carrier by a step-by-step impregnation method and then drying and calcining.

[0016] Preferably, the main component of the composite oxide support is Al 2 O 3The mass fraction of TiO is 80%-90%, 2 The mass fraction is 10%-20%.

[0017] Preferably, the specific surface area of ​​the composite oxide carrier is 220-380m 2 / g, pore volume is 0.7-1.5mL / g, and average pore diameter is 10-15nm.

[0018] Preferably, the impregnation aid is a phosphoric acid impregnation solution, H 3 PO 4 The mass fraction is 0.1%-10%.

[0019] Preferably, the active component Co and Mo precursors are selected from one or more of nitrates, phosphates, acetates and ammonium salts containing cobalt or molybdenum.

[0020] Preferably, based on the total weight of the catalyst, the content of CoO and MoO 3 CoO is 1-7%, MoO 3 5-20%, the rest is Al 2 O 3 -TiO 2 The composite support, more preferably, CoO is 3-5%, MoO 3 If it is not within the above range, the number of active sites will be reduced or the dispersion of active components will be reduced, thereby the catalytic activity of the catalyst will be deteriorated.

[0021] The preparation method of the synergistic catalyst Z2 can be a conventional impregnation method or other similar methods, which can be freely selected by those skilled in the art according to the prior art, for example, but not limited to, the following method can be used for preparation:

[0022] Take a certain concentration of phosphoric acid aqueous solution and mix Al 2 O 3 and TiO 2 The composite support was added and impregnated for 2 hours, dried at room temperature and then dried at 110°C for 8 hours, and calcined at 450°C for 4 hours to obtain a phosphorus-modified titanium aluminum support; Co(NO 3 ) 2 6H 2 O, and (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was dissolved in deionized water, and then added into the modified titanium aluminum carrier and impregnated for 6 hours. After drying and calcining, it was ground into 40 mesh powder to obtain the synergistic catalyst Z2.

[0023] According to the second aspect of the present invention, another object of the present invention is to provide use of the synergistic catalyst in the hydrorefining of coking crude benzene.

[0024] According to the third aspect of the present invention, another object of the present invention is to provide a method for hydrogenating and refining coking crude benzene, the method using the synergistic catalyst according to the present invention, the method is a two-step hydrogenation method, comprising the following steps:

[0025] 1) Pre-reaction hydrogenation catalysis;

[0026] 2) Main reaction hydrogenation catalysis. In the main reaction hydrogenation catalytic reactor, the synergistic catalyst Z1 is placed on the upper layer of the synergistic catalyst Z2. The loading mass fraction of the synergistic catalyst Z1 is 10%-24%, and the loading mass fraction of the synergistic catalyst Z2 is 76%-90%. The hydrogenation catalysis is a reaction well known in the art, and the reaction conditions can be adjusted by those skilled in the art according to actual needs.

[0027] The pre-reaction hydrogenation can be carried out by conventional techniques in the art, and the pre-reaction hydrogenation catalyst used is a Ni-Mo hydrogenation catalyst in the prior art. Those skilled in the art can freely select the catalyst based on the prior art at their disposal, and the present invention will not elaborate on it.

[0028] Compared with the prior art, the technical solution of the above embodiment of the present invention has the following beneficial effects:

[0029] (1) A two-step hydrogenation process using a pre-reaction catalyst and a desiliconization and dechlorination synergistic catalyst is selected. The pre-reaction catalyst removes unsaturated olefins and a portion of organic chlorine, the synergistic catalyst Z1 removes organic silicon, and the synergistic catalyst Z2 removes impurities such as chlorine, sulfur, and nitrogen. Compared with the desiliconizer and dechlorinator in the prior art, the catalyst has strong specificity, higher activity, better removal effect, and longer service life.

[0030] (2) MgO in the synergistic catalyst Z1 can absorb HCl generated by the crude benzene pre-reaction, thereby protecting Al 2 O 3 The catalyst structure will not be corroded and collapse, ensuring that the pore volume and pore size are not destroyed, adapting to the high chlorine environment in crude benzene and extending the desiliconization life.

[0031] (3) The synergistic catalyst Z1 uses glycerol monomethyl ether to hydrothermally treat magnesium aluminum spinel, which can increase the number of hydroxyl groups on the surface of Z1, and the hexaligand Al 6 Combine with more hydroxyl groups to form Al-OH. The Si in the silicon-containing compound and the oxygen in Al-OH form an Os (transition state)-Si bond, which can firmly adsorb Si on Al 2 O 3 surface, improving adsorption efficiency.

[0032] (4) Compared with the desiliconization of the same catalyst carrier and then loading the active components to remove chlorine, sulfur and nitrogen, the synergistic catalyst Z1 does not load the active components, which can reduce the damage of the active components to the hydroxyl groups on the carrier surface and increase the silicon capacity of Z1; the adsorption of silicon will not affect the catalytic activity of the active components loaded on the synergistic catalyst Z2, and the removal efficiency is higher and the service life is longer. The amount of active components is also reduced, avoiding excessive hydrogenation to hydrogenate benzene to form cyclohexane, and improving the benzene yield.

[0033] (5) Introduction of TiO into the support of synergistic catalyst Z2 2 , which can weaken the interaction between Mo and carrier Al 2 O 3 The strong interaction between the two promotes the formation of Co-Mo-S active phase on the support surface, which is easy to reduce and sulfide and has higher activity.

[0034] The additive P is first loaded on the carrier, and then loaded with the active component after calcination, which can increase the acid sites on the carrier and promote the formation of the active phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 The present invention is a schematic diagram of a process flow for hydrorefining, desiliconization and dechlorination of coking crude benzene provided according to one embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, the present invention will be described in detail. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present invention, so that it should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0038] In this document, the terms "include", "including", "have", "contain" or any other similar terms are open conjunctions, which are intended to cover non-exclusive inclusions. For example, a composition or product containing multiple elements is not limited to the elements listed herein, but may also include other elements that are not explicitly listed but are generally inherent to the composition or product. In addition, unless otherwise explicitly stated, the term "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and A and B are both true (or exist). In addition, in this document, the interpretation of the terms "include", "including", "have", and "contain" should be considered to have been specifically disclosed and simultaneously cover closed or semi-closed conjunctions such as "consisting of" and "consisting essentially of".

[0039] In this article, all features or conditions defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have covered and specifically disclosed all possible secondary ranges and individual values ​​within the range, especially integer values. For example, the range description of "1 to 8" should be deemed to have specifically disclosed all secondary ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially secondary ranges defined by all integer values, and should be deemed to have specifically disclosed individual values ​​such as 1, 2, 3, 4, 5, 6, 7, 8, etc. within the range. Unless otherwise specified, the above interpretation method applies to all contents of the entire present invention, regardless of whether the range is broad or not.

[0040] If the quantity or other numerical value or parameter is expressed as a range, a preferred range or a series of upper and lower limits, it should be understood that all ranges consisting of any upper limit or preferred value of the range and the lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, if a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0041] In this document, under the premise of achieving the purpose of the invention, numerical values ​​should be understood to have the accuracy of the number of significant digits of the numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0042] In order to clarify the present invention, parts irrelevant to the description are omitted in the drawings, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0043] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

[0044] Throughout the specification, when it is mentioned that a certain element is “connected” to another element, it includes not only “direct connection” but also “indirect connection” between other components. In addition, when it is mentioned that a certain element “includes” a certain component, it means that the element may further include other components rather than excluding other components, unless explicitly described to the contrary.

[0045] according to Figure 1 , the raw material coking crude benzene (high chlorine and high silicon crude benzene) is transported to the pre-reactor together with hydrogen through a reciprocating pump for pre-hydrogenation reaction. The product of the pre-hydrogenation reaction is directly transported from the bottom of the pre-reactor to the heating furnace through a pipeline without purification, and is transported to the top of the main reactor for hydrogenation refining after heating. The main reactor is equipped with a synergistic catalyst Z1 layer and a synergistic catalyst Z2 layer, wherein the synergistic catalyst Z1 layer is located above the synergistic catalyst Z2 layer, wherein the synergistic catalyst Z1 layer can effectively remove the organosilicon contained in the coking crude benzene, and protect the synergistic catalyst Z2 from the influence of organosilicon impurities, while the synergistic catalyst Z2 can effectively remove impurities such as chlorine, sulfur, and nitrogen. A layer of screen is set between the synergistic catalyst Z1 layer and the synergistic catalyst Z2 layer for separation. After the reaction is completed, the refined low-chlorine and low-silicon crude benzene is discharged through a buffer tank, and impurities such as chlorine and hydrogen sulfide are discharged from the system in a gaseous state.

[0046] The following examples are only listed as examples of embodiments of the present invention and do not constitute any limitation to the present invention. It can be understood by those skilled in the art that modifications within the scope of the essence and concept of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0047] Example 1

[0048] Dilute 10.6 g of glycerol monomethyl ether with water and add it to a 1 L volumetric flask to make a solution with a concentration of 0.1 mol / L. 2 O 3 20 g of magnesium aluminum spinel powder with an A:MgO ratio of 75:25 was added into a 500 ml stainless steel reactor, and then 100 ml of the above-prepared glycerol monomethyl ether solution was added. The reactor was closed and heated to 210°C under a nitrogen atmosphere, with a stirring speed of 100 r / min and kept warm for 2.5 h. After cooling to room temperature, the mixture was filtered, dried, and ground into a 40 mesh powder to obtain catalyst Z1.

[0049] Take 150ml of 0.5%wt phosphoric acid aqueous solution and mix the purchased Al 2 O 3:TiO 2 = 90:10 composite carrier 50g was added thereto and impregnated for 2h, dried at room temperature and then dried at 110°C for 8h, and calcined at 450°C for 4h to obtain a phosphorus-modified titanium aluminum carrier; 4.36g Co(NO 3 ) 2 6H 2 O, 11.02 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was dissolved in 150 ml of deionized water, and then added into the modified titanium aluminum carrier and impregnated for 6 hours. After drying and calcining, it was ground into 40 mesh powder to obtain catalyst Z2.

[0050] Example 2

[0051] Dilute 21.2 g of glycerol monomethyl ether with water and add the solution to a 1 L volumetric flask to a concentration of 0.2 mol / L. 2 O 3 20g of magnesium aluminum spinel powder with an A:MgO ratio of 80:20 was added into a 500ml stainless steel reactor, and then 100ml of glycerol monomethyl ether solution was added, the reactor was closed, and the temperature was raised to 210°C under a nitrogen atmosphere, the stirring speed was 100r / min, and the temperature was kept for 2.5h. After cooling to room temperature, the mixture was filtered and dried, and ground into 40 mesh powder to obtain catalyst Z1.

[0052] Take 150ml of 1%wt phosphoric acid aqueous solution and mix the purchased Al 2 O 3 :TiO 2 = 90:10 composite carrier 50g was added thereto and impregnated for 2h, dried at room temperature and then dried at 110°C for 8h, and calcined at 450°C for 4h to obtain a phosphorus-modified titanium aluminum carrier; 8.72g Co(NO 3 ) 2 6H 2 O, 11.02 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was dissolved in 150 ml of deionized water, and then added into the modified titanium aluminum carrier and impregnated for 6 hours. After drying and calcining, it was ground into 40 mesh powder to obtain catalyst Z2.

[0053] Example 3

[0054] Dilute 42.4 g of glycerol monomethyl ether with water and add the solution to a 1 L volumetric flask to a concentration of 0.4 mol / L. 2 O 320 g of magnesium aluminum spinel powder with an A:MgO ratio of 85:15 was added into a 500 ml stainless steel reactor, and then 100 ml of glycerol monomethyl ether solution was added. The reactor was closed and heated to 210°C under a nitrogen atmosphere, with a stirring speed of 100 r / min and kept warm for 2.5 h. After cooling to room temperature, the mixture was filtered, dried, and ground into 40 mesh powder to obtain catalyst Z1.

[0055] Take 150ml of 1.5%wt phosphoric acid aqueous solution and mix the purchased Al 2 O 3 :TiO 2 = 85:15 composite carrier 50g was added and impregnated for 2h, dried at room temperature and then dried at 110°C for 8h, and calcined at 450°C for 4h to obtain a phosphorus-modified titanium aluminum carrier; 13.08g Co(NO 3 ) 2 6H 2 O, 13 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was dissolved in 150 ml of deionized water, and then added into the modified titanium aluminum carrier and impregnated for 6 hours. After drying and calcining, it was ground into 40 mesh powder to obtain catalyst Z2.

[0056] Example 4

[0057] Dilute 21.2 g of glycerol monomethyl ether with water and add the solution to a 1 L volumetric flask to a concentration of 0.2 mol / L. 2 O 3 20 g of magnesium aluminum spinel powder with an A:MgO ratio of 75:25 was added into a 500 ml stainless steel reactor, and then 100 ml of glycerol monomethyl ether solution was added. The reactor was closed and heated to 210°C under a nitrogen atmosphere, with a stirring speed of 100 r / min and kept warm for 2.5 h. After cooling to room temperature, the mixture was filtered, dried, and ground into 40 mesh powder to obtain catalyst Z1.

[0058] Take 150ml of 0.5%wt phosphoric acid aqueous solution and mix the purchased Al 2 O 3 :TiO 2 = 85:15 composite carrier 50g was added thereto and impregnated for 2h, dried at room temperature and then at 110°C for 8h, and calcined at 450°C for 4h to obtain a phosphorus-modified titanium-aluminum carrier; 4.36g Co(NO 3 ) 2 6H 2 O, 13 g (NH 4 ) 6 Mo 7 O 24·4H 2 O was dissolved in 150 ml of deionized water, and then added into the modified titanium aluminum carrier and impregnated for 6 hours. After drying and calcining, it was ground into 40 mesh powder to obtain catalyst Z2.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that catalyst Z1 is prepared according to the process in Example 1, and catalyst Z2 is not prepared.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 2 is that the composite carrier Al of catalyst Z2 in Example 2 2 O 3 :TiO 2 =90:10 changed to γ-Al 2 O 3 , the other conditions remain unchanged.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 3 is that the magnesium aluminum spinel Al 2 O 3 :MgO=85:15 changed to Al 2 O 3 , that is, it does not contain MgO and is not impregnated with glycerol monomethyl ether, while the other conditions remain unchanged.

[0065] Comparative Example 4

[0066] The difference between this comparative example and Example 4 is that 4.36 g of Co(NO 3 ) 2 6H 2 O and 13 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was replaced by 21.8 g of Co(NO 3 ) 2 6H 2 O and 6.89 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O, the other conditions remain unchanged.

[0067] The acid properties and pore properties of the catalysts in the above examples and comparative examples were compared, and the analysis results are shown in Table 1.

[0068] Table 1 Physicochemical properties of different catalysts

[0069]

[0070] It can be seen from Table 1 that the synergistic catalyst according to the present invention has a larger specific surface area and pore volume through a specific process, a larger number of surface hydroxyl groups, and a higher activity.

[0071] according to Figure 1 A catalyst evaluation device was assembled, in which the main reactor and the pre-reactor were both reaction tubes of Φ20×1000 mm. The raw material used was coking crude benzene, and the properties of the crude benzene were shown in Table 2 below.

[0072] Table 2 Crude benzene properties

[0073]

[0074] Example 5

[0075] The commercially available pre-hydrogenation catalyst M8-21 produced by BASF of Germany was added into the pre-reactor, 18g Z2 catalyst in Example 1 was loaded into the lower layer of the main reactor, and 2g Z1 catalyst was loaded into the upper layer of the main reactor. After pre-sulfurization activation treatment, coking crude benzene was pumped in with a plunger pump, mixed with hydrogen in the feed pipeline, and entered the pre-reactor together to remove unsaturated olefins, and then heated in a heating furnace and entered the main reactor to remove silicon, chlorine, sulfur and nitrogen. The pre-reaction temperature was 190°C, the main reaction temperature was 300°C, the hydrogenation pressure was 2.5MPa, and the volume space velocity was 2h -1 , hydrogen to oil volume ratio of 500, after 6 hours of reaction, the hydrogenated crude benzene was collected for analysis.

[0076] Example 6

[0077] 18 g of Z2 catalyst in Example 2 was loaded into the lower layer of the main reactor, and 2 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as in Example 5.

[0078] Example 7

[0079] 16 g of Z2 catalyst in Example 3 was loaded into the lower layer of the main reactor, and 4 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as in Example 5.

[0080] Example 8

[0081] 16 g of Z2 catalyst in Example 4 was loaded into the lower layer of the main reactor, and 4 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as in Example 5.

[0082] Comparative Example 5

[0083] 20 g of Z1 catalyst in Comparative Example 1 was loaded into the main reactor without loading Z2 catalyst. The remaining operations were the same as those in Example 5.

[0084] Comparative Example 6

[0085] 10 g of Z2 catalyst in Comparative Example 2 was loaded into the lower layer of the main reactor, and 10 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as those in Example 5.

[0086] Comparative Example 7

[0087] 16 g of Z2 catalyst in Comparative Example 3 was loaded into the lower layer of the main reactor, and 4 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as those in Example 5.

[0088] Comparative Example 8

[0089] 16 g of Z2 catalyst in Comparative Example 4 was loaded into the lower layer of the main reactor, and 4 g of Z1 catalyst was loaded into the upper layer of the main reactor. The remaining operations were the same as those in Example 5.

[0090] The hydrogenation impurity removal activities of Examples 5 to 8 and Comparative Examples 5 to 8 are shown in Table 3 below.

[0091] Table 3 Comparison of synergistic catalyst impurity removal activity

[0092]

[0093] From the data in Table 3, it can be seen that the four synergistic desiliconization and dechlorination catalysts of Examples 5-8 can maintain high activity in a high-chlorine and high-silicon environment after being prepared in a specific ratio, and can remove Si from crude benzene to ≤1ppm, and remove Cl, N, and S to ≤5ppm, and benzene is not hydrogenated to form cyclohexane. However, Comparative Example 5 only uses a single desiliconizing agent, so the desiliconization effect is better, but there is no effect of removing Cl, N, and S. In Comparative Example 6, the Z1 content is too high, and TiO is not introduced into the Z2 carrier. 2 , resulting in weak activity of the main catalyst and poor removal of Cl, N, and S. In Comparative Example 7, catalyst Z1 is selected from Al 2 O 3 It has not been treated with glycerol monomethyl ether, has a low hydroxyl content, and is not susceptible to Al in a high chlorine environment. 2 O 3 It cannot withstand the corrosion of strong hydrochloric acid, deactivates quickly, and has a relatively poor desiliconization effect. The content of the two active components Co / Mo in Comparative Example 8 exceeds the range specified in this specification, resulting in a smaller pore volume on the carrier, a poor desulfurization effect, and a significant increase in the cyclohexane content, indicating the presence of over-hydrogenation.

[0094] In summary, the synergistic catalyst and preparation method thereof provided by the present invention can effectively remove impurities such as silicon, chlorine, sulfur, and nitrogen in crude benzene to ≤5ppm, while reducing the occurrence of carbon deposition, greatly extending the life of the catalyst, and will not excessively hydrogenate to reduce the yield of pure benzene, thereby meeting the long-term stable operation of the equipment.

[0095] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A synergistic catalyst for hydrorefining of coking crude benzene, the synergistic catalyst comprising synergistic catalyst Z1 and synergistic catalyst Z2 loaded in layers in a reactor in a specific mass ratio, wherein synergistic catalyst Z1 has the function of removing organic silicon impurities, and synergistic catalyst Z2 has the function of removing chlorine, sulfur and nitrogen impurities; In the reactor, the synergistic catalyst Z1 is placed on the upper layer of the synergistic catalyst Z2, the loading mass fraction of the synergistic catalyst Z1 is 10%-24%, and the loading mass fraction of the synergistic catalyst Z2 is 76%-90%; The synergistic catalyst Z1 is prepared from magnesium-aluminum spinel treated with a hydroxyl auxiliary agent by hydrothermal treatment, wherein: The Al species of Al2O3 in magnesia-alumina spinel is hexa-coordinated AlO6 with an octahedral structure; The synergistic catalyst Z2 is a supported catalyst, with the composite oxide Al2O3-TiO2 as the carrier, and the auxiliary agent and the active component Co and Mo precursor solution are sequentially impregnated by a step-by-step impregnation method, and then dried and calcined to obtain the synergistic catalyst Z2.

2. The synergistic catalyst according to claim 1, characterized in that In the reactor, the loading mass fraction of the synergistic catalyst Z1 is 14%-18%, and the loading mass fraction of the synergistic catalyst Z2 is 82%-86%.

3. The synergistic catalyst according to claim 1, characterized in that The mass ratio of Al2O3:MgO in the magnesium-aluminum spinel in the synergistic catalyst Z1 is (74-86):(26-14), and the specific surface area is 400-550m 2 / g, pore volume is 1.2-1.5ml / g; Preferably, the mass ratio of Al2O3:MgO in the magnesium-aluminum spinel is (78-82):(22-18); Preferably, the hydroxy auxiliary agent is selected from glycerol monomethyl ether, propylene glycol and butylene glycol, preferably glycerol monomethyl ether; Preferably, the heat treatment conditions of the hydroxyl auxiliary agent are as follows: 15g-25g of magnesium aluminum spinel and 100ml-200ml of glycerol monomethyl ether solution are added into the reactor with a concentration of 0.1-0.5mol / L, a reaction temperature of 205-220°C, a reactor speed of 100r / min, a reaction time of 2.5h, followed by cooling, depressurizing and drying to constant weight.

4. The synergistic catalyst according to claim 1, characterized in that In the synergistic catalyst Z2, the mass fraction of the main component Al2O3 in the composite oxide carrier is 80%-90%, and the mass fraction of TiO2 is 10%-20%; Preferably, the specific surface area of ​​the composite oxide carrier is 220-380m 2 / g, pore volume is 0.7-1.5mL / g, and average pore diameter is 10-15nm; Preferably, the impregnation aid is a phosphoric acid impregnation solution, and the mass fraction of H3PO4 is 0.1%-10%; Preferably, the active component Co and Mo precursors are selected from one or more of nitrates, phosphates, acetates, and ammonium salts containing cobalt or molybdenum; Preferably, based on the total weight of the catalyst, calculated in terms of CoO and MoO3, CoO is 1-7%, MoO3 is 5-20%, and the rest is an Al2O3-TiO2 composite carrier, more preferably, CoO is 3-5%, and MoO3 is 9-14%.

5. Use of the synergistic catalyst according to any one of claims 1 to 4 in the hydrorefining of coking crude benzene.

6. A method for hydrogenating and refining coked crude benzene, the method using the synergistic catalyst according to any one of claims 1 to 4, the method is a two-step hydrogenation method, comprising the following steps: 1) Pre-reaction hydrogenation catalysis; 2) Main reaction hydrogenation catalysis: in the main reaction hydrogenation catalytic reactor, the synergistic catalyst Z1 is placed on the upper layer of the synergistic catalyst Z2, the loading mass fraction of the synergistic catalyst Z1 is 10%-24%, and the loading mass fraction of the synergistic catalyst Z2 is 76%-90%.

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