A method for producing more benzene by combined processing

Abstract

The present disclosure relates to a combined processing method for producing more benzene, which comprises: subjecting crude oil to a pre-hydrogenation reaction, and subjecting at least part of the obtained pre-hydrogenation reaction product to a first separation to obtain C 6‑7 Naphtha and C 7+ Naphtha; C 6‑7 The naphtha is aromatized to obtain aromatized hydrogen and the first benzene-rich aromatics; 7+ After the naphtha is reformed, reformed C 6‑7 Naphtha and reformed C8 aromatics, C 9+ Aromatics and heavy aromatics; C 9+ Aromatic hydrocarbons enter the aromatic hydrocarbon dealkylation unit for dealkylation treatment to obtain second benzene-rich aromatic hydrocarbons; the first benzene-rich aromatic hydrocarbons and the reformed C 6‑7 The naphtha and the second benzene-rich aromatics enter the aromatics extraction unit for aromatics extraction, yielding a non-aromatic raffinate, a benzene-rich product, and a toluene component. The disclosed technical solution can reduce raw material costs, hydrogen usage, and naphtha usage, increase benzene production, and achieve good economic benefits.

Description

Technical Field

[0001] The present disclosure relates to the field of petrochemical industry, and in particular, to a method for producing more benzene by combined processing. Background Art

[0002] Benzene is a key aromatic hydrocarbon and an important organic chemical raw material. Pure benzene is a raw material for the production of important chemical products such as styrene, phenol, aniline, MDI, adipic acid, and caprolactam, and has a significant overall market potential.

[0003] Pure benzene can be divided into petroleum benzene and coking benzene according to the source of raw materials. The process of producing pure benzene in the petrochemical industry includes catalytic reforming, steam cracking, catalytic cracking, toluene disproportionation (TDP), toluene hydrodealkylation (HDA), heavy aromatics lightening, C 9+ Dealkylation technology, light naphtha alkane aromatization, etc. In addition, benzene can also be separated from coke oven light oil and coal tar.

[0004] For an entire refinery, the impact of a single technological advantage on overall plant performance is very limited. Only by integrating multiple key single-point technologies from a holistic perspective can we overcome these limitations, truly achieve more efficient and rational utilization of resources (raw materials, hydrogen, equipment, land, and human resources), optimize and improve product structure and quality, and better support the petrochemical industry's pursuit of higher-quality development. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a method for producing more benzene by combined processing, so as to solve the problems of high raw material cost, high hydrogen consumption and low economic benefit existing in the prior art.

[0006] In order to achieve the above-mentioned object, the present disclosure provides a method for producing more benzene by combined processing, which comprises: allowing the raw oil to enter a pre-hydrogenation device for pre-hydrogenation reaction to obtain a pre-hydrogenation reaction product; subjecting at least part of the pre-hydrogenation reaction product to a first separation to obtain C 6-7 Naphtha and C 7+ Naphtha; make the C 6-7 Naphtha enters the alkane aromatization unit for aromatization reaction to obtain aromatized hydrogen and the first benzene-rich aromatics; 7+ The naphtha enters the reforming unit for reforming treatment to obtain reformed hydrogen and reformed oil; the reformed oil is subjected to a second separation to obtain reformed C 6-7 Naphtha, C8 aromatics, C 9+ Aromatics and heavy aromatics; making the C 9+ Aromatic hydrocarbons enter the aromatic hydrocarbon dealkylation unit for dealkylation treatment to obtain second benzene-rich aromatic hydrocarbons; the first benzene-rich aromatic hydrocarbons and the reformed C 6-7The naphtha and the second benzene-rich aromatics enter an aromatics extraction unit for aromatics extraction treatment to obtain non-aromatic raffinate, a benzene-rich product, and a toluene component; the non-aromatic raffinate is returned to the alkane aromatization unit, and the toluene component is returned to the aromatics dealkylation unit; the reformed hydrogen is divided into at least a first portion of reformed hydrogen and a second portion of reformed hydrogen, the first portion of reformed hydrogen enters the pre-hydrogenation unit, and the second portion of reformed hydrogen enters the aromatics dealkylation unit.

[0007] Optionally, the feedstock oil is selected from oil products with an initial boiling point of 60-70°C and a final boiling point of 170-180°C, preferably one or more of straight-run heavy naphtha, steam cracking raffinate oil, catalytic cracking raffinate oil and hydrogenated naphtha.

[0008] Optionally, the reaction conditions of the pre-hydrogenation reaction include: a reaction temperature of 280-340°C, a reaction pressure of 2.4-3.8 MPa, a hydrogen partial pressure of 2.16-3.42 MPa, a volume ratio of the pre-hydrogenation feed hydrogen to the feed oil of (90-100):1; the catalyst used in the pre-hydrogenation reaction includes RS-1 catalyst or S-125 catalyst. Optionally, the reaction conditions of the aromatization reaction include: a reaction temperature of 450-530°C, a reaction pressure of 0.3-1.0 MPa, a reaction mass space velocity of 1.0-1.5 h -1 ; The catalyst used in the aromatization reaction is PL-90 catalyst.

[0009] Optionally, the C 6-7 C in naphtha 8+ The content of the components is below 0.1 wt %, the sulfur content in the mixed aromatization feed is below 0.1 ppm, and the water content is below 1 ppm.

[0010] Optionally, before the dealkylation treatment, the exogenous C 9+ Components and the C 9+ Aromatic hydrocarbon mixture; the dealkylation treatment conditions include: temperature of 420-540 ° C, pressure of 3.6-6.2 MPa, hydrogen partial pressure of 2.52-5.58 MPa, hydrogen-to-oil volume ratio of (3.0-4.0): 1.

[0011] Optionally, a portion of the reformed hydrogen is used as pre-hydrogenation feed hydrogen to enter the pre-hydrogenation unit, and a portion of the reformed hydrogen is used as dealkylation feed hydrogen to enter the aromatic dealkylation unit.

[0012] Optionally, the reformed hydrogen further includes third reformed hydrogen, and the third reformed hydrogen is sent to other hydrogen-using devices.

[0013] Optionally, the method further comprises mixing the second portion of reformed hydrogen with externally purchased hydrogen and then introducing the mixture into the aromatic dealkylation unit.

[0014] Optionally, the reforming C 6-7 C in naphtha 8+ The content of the component is below 0.1% by weight; the C 9+ C in aromatics 10+ The content of the component is below 2% by weight.

[0015] Through the above technical solution, the present invention pre-hydrogenates and separates the crude oil to obtain C 6-7 Naphtha components and C 7+ Naphtha components; among them, C 6-7 Naphtha components and non-aromatic raffinate are converted into benzene through aromatization of paraffins, C 7+ The naphtha components are reformed and separated to obtain C 9+ Aromatic hydrocarbons are converted into benzene through aromatic dealkylation. The disclosed method can expand and optimize the raw material sources for benzene production, reduce raw material costs, and improve economic benefits. Furthermore, the hydrogen used in the pre-hydrogenation reaction and dealkylation treatment in the disclosed method comes from the reforming unit, saving hydrogen consumption and further reducing raw material costs.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0018] Figure 1 The present invention is a flow chart of a method for producing more benzene using a combined process.

[0019] Figure 2 It is a schematic diagram of the method for producing more benzene by the combined process of Comparative Example 1 of the present disclosure.

[0020] Figure 3 It is a schematic diagram of the method for producing more benzene by the combined process of Example 1 of the present disclosure.

[0021] Description of Reference Numerals

[0022] 1. Pre-hydrogenation unit; 2. First separation unit; 3. Alkane aromatization unit; 4. Reforming unit; 5. Second separation unit; 6. Aromatic dealkylation unit; 7. Aromatic extraction unit; 100. Straight-run heavy naphtha; 101. Steam cracking raffinate; 102. Catalytic cracking raffinate; 103. Hydrogenated naphtha; 104. Feedstock oil; 105. Pre-hydrogenation reaction product; 106. C 6-7 Naphtha; 107, mixed aromatization feed; 108, first benzene-rich aromatics; 109, mixed aromatics; 110, pre-hydrogenation reaction product; 111, C 7+ Naphtha; 112, reformate; 113, reformate C 6-7 Naphtha; 114, C 9+ Aromatics; 115, second benzene-rich aromatics; 116, non-aromatic raffinate; 117, benzene-rich product; 118, toluene component; 119, foreign toluene component; 120, foreign C 9+ Components: 201, first part of reformed hydrogen; 202, second part of reformed hydrogen; 203, aromatization hydrogen; 204, C8 aromatics; 205, heavy aromatics; 206, third part of reformed hydrogen; 207, purchased hydrogen. DETAILED DESCRIPTION

[0023] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0024] In this disclosure, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower positions of a device in normal use. Figure 1 In the drawing orientation, "inside" and "outside" refer to the device outline. Furthermore, the terms "first, second, and third" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, features defined as "first, second, and third" may explicitly or implicitly include one or more of the features. In the description of this disclosure, "plurality" means two or more, unless otherwise specifically defined.

[0025] The present disclosure provides a combined processing method for producing more benzene, comprising: allowing crude oil to enter a pre-hydrogenation device 1 for a pre-hydrogenation reaction to obtain a pre-hydrogenation reaction product; subjecting at least part of the pre-hydrogenation reaction product to a first separation to obtain C 6-7 Naphtha and C 7+ Naphtha; make the C 6-7 Naphtha enters the alkane aromatization unit 3 for aromatization reaction to obtain aromatized hydrogen and the first benzene-rich aromatics; 7+The naphtha enters the reforming unit 4 for reforming treatment to obtain reformed hydrogen and reformed oil; the reformed oil is subjected to a second separation to obtain reformed C 6-7 Naphtha, C8 aromatics, C 9+ Aromatics and heavy aromatics; making the C 9+ Aromatic hydrocarbons enter the aromatic hydrocarbon dealkylation unit 6 for dealkylation treatment to obtain second benzene-rich aromatic hydrocarbons; the first benzene-rich aromatic hydrocarbons and the reformed C 6-7 The naphtha and the second benzene-rich aromatics enter the aromatics extraction unit 7 for aromatics extraction treatment to obtain non-aromatic raffinate, a benzene-rich product and a toluene component; the non-aromatic raffinate is returned to the alkane aromatization unit, and the toluene component is returned to the aromatics dealkylation unit 6; the reformed hydrogen is divided into at least a first portion of reformed hydrogen and a second portion of reformed hydrogen, the first portion of reformed hydrogen enters the pre-hydrogenation unit 1, and the second portion of reformed hydrogen enters the aromatics dealkylation unit 6.

[0026] Through the above technical solution, the present invention pre-hydrogenates and separates the crude oil to obtain C 6-7 Naphtha components and C 7+ Naphtha components; among them, C 6-7 Naphtha components and non-aromatic raffinate are converted into benzene through aromatization of paraffins, C 7+ The naphtha components are reformed and separated to obtain C 9+ Aromatic hydrocarbons are converted into benzene through aromatic dealkylation. The disclosed method can expand the raw material sources for benzene production, reduce raw material costs, and improve economic benefits. Furthermore, the hydrogen used in the pre-hydrogenation reaction and dealkylation treatment in the disclosed method is derived from the reformer 4, which can save hydrogen consumption and further reduce raw material costs.

[0027] In one embodiment, the feedstock oil used in the present disclosure can be selected from oils having an initial boiling point of 60-70°C and a final boiling point of 170-180°C, preferably one or more of straight-run heavy naphtha, steam cracking raffinate, catalytic cracking raffinate, and hydrogenated naphtha. That is, the distillation range (ASTM D-86) of the feedstock oil is preferably 65-175°C. In this embodiment, ASTM D-86 refers to the test method numbered D86 published by the American Society for Testing and Materials: Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure.

[0028] The method for the pre-hydrogenation reaction performed in the present disclosure is a conventional method in the art, and the present application does not make any special requirements. For example, in one embodiment of the present disclosure, the reaction conditions of the pre-hydrogenation reaction include: a reaction temperature of 280-340°C, preferably 280-320°C; a reaction pressure of 2.4-3.8 MPa, preferably 2.4-2.8 MPa; a hydrogen partial pressure of 2.16-3.42 MPa, preferably 2.16-2.52 MPa; and a volume ratio of the pre-hydrogenation feed hydrogen to the feed oil of (90-100):1; preferably 90:1.

[0029] The catalyst used in the pre-hydrogenation reaction disclosed herein is conventionally selected in the art and is not specifically required in this application. For example, in one embodiment of the present disclosure, the catalyst used in the pre-hydrogenation reaction includes RS-1 catalyst or S-125 catalyst, preferably RS-1 catalyst.

[0030] In the above embodiment, by using the above reaction conditions and catalyst, inexpensive feedstock oil can be converted into refined naphtha, and the reactivity of the preliminary hydrogenation reaction can be enhanced.

[0031] In one embodiment, the first separation is carried out in a first naphtha separation device; the first separation device is conventionally selected in the art, for example, the first separation device can be a naphtha fractionation device, and further, the naphtha fractionation device can be a C7 removal tower.

[0032] In this embodiment, the pre-hydrogenation reaction product can be separated into C and C residues that can be used for the alkane aromatization reaction by the first separation. 6-7 Naphtha and C 7+ Naphtha, according to the feed scale requirements of subsequent alkane aromatization reaction and reforming treatment, it should be noted that C 6-7 C in naphtha 8+ The content of the component must be below 0.1 wt%. In addition, the C7 component can be present in the C 6-7 In naphtha, it can also be present in C 7+ In naphtha; the C 6-7 The C7 component in naphtha and the C 6-7 The weight ratio of naphtha and the C 7+ The C7 component in naphtha and the C 7+ There is no fixed requirement for the weight ratio of naphtha, which is determined according to the specific aromatization and reforming scale.

[0033] In one embodiment, the non-aromatic raffinate oil is mixed with the C 6-7The mixed aromatization feed obtained by mixing naphtha enters the aromatic dealkylation unit 6 to contact the catalyst and undergo aromatization reaction under aromatization reaction conditions; the reaction conditions of the aromatization reaction include: reaction temperature of 450-530°C, preferably 450-500°C; reaction pressure of 0.3-1.0 MPa, preferably 0.3-0.5 MPa; reaction mass space velocity of 1.0-1.5 h -1 Preferably 1.2-1.5h -1 .

[0034] The catalyst used in the aromatization reaction of the present disclosure is a conventional choice in the art, and this application does not make any special requirements. For example, in a specific embodiment of the present disclosure, the catalyst used in the aromatization reaction is a PL-90 catalyst.

[0035] In the above embodiment, the mixed aromatization feed for the aromatization reaction may be paraffin and / or cycloparaffin, preferably paraffin; wherein the impurity content requirements of the mixed aromatization feed include a sulfur content of less than 0.1 ppm, a moisture content of less than 1 ppm, a nitrogen content of less than 0.5 ppm, a lead content of less than 1 ppb, a copper content of less than 1 ppb, and an arsenic content of less than 1 ppb.

[0036] In order to make the system's treatment effect match the properties of the feedstock oil, the pre-hydrogenation reaction products produced by the pre-hydrogenation reaction can all enter the first separation device 2, or a portion of the pre-hydrogenation reaction products can also enter the first separation device 2. There is no fixed requirement for the weight of the partial pre-hydrogenation reaction products subjected to the first separation and the pre-hydrogenation reaction products, which are determined according to the specific aromatization and reforming scales. In addition, if the raw material undergoing the hydrogenation reaction is a feedstock oil of good quality, the hydrogenation reaction products can also all enter the reforming unit 4 for subsequent processing.

[0037] In a preferred embodiment, before the reforming treatment, a portion of the pre-hydrogenation reaction product is mixed with the C 7+ Naphtha mixing, a portion of the pre-hydrogenation reaction product and the C 7+ There is no fixed requirement for the weight ratio of naphtha, which is determined according to the specific aromatization and reforming scale.

[0038] In the above embodiment, the reformer 4 and the reforming treatment are conventionally selected in the art, and this application does not make special requirements. For example, the conditions of the reforming treatment include: a pressure of 0.35 MPa, an inlet temperature of the reformer 4 of 526-538°C, preferably 526-532°C; a reforming space velocity of 1.2-2.25h -1 , preferably 1.5-2.0h -1 .

[0039] In one embodiment, the second separation is performed in the second separation device 5, wherein the reformed oil separation device includes a C7 removal tower, a xylene tower and a heavy aromatics tower. In this embodiment, the second separation can separate the reformed oil into reformed C 6-7 Naphtha and reformed aromatics, among which reformed aromatics include: C8 aromatics, C 9+ Aromatics and heavy aromatics.

[0040] In this embodiment, the C7 removal tower can remove the reformed C in the reformed oil. 6-7 Naphtha and C 8+ Components are separated; among them, the separation requirement of the C7 tower is to reform C 6-7 C in naphtha 8+ The content of the component is below 0.1 wt%. In addition, the heavy aromatics tower separation requirement is to reform C 9+ C in aromatic components 10+ The component is less than 2% by weight.

[0041] In one embodiment, the dealkylation treatment conditions include: a temperature of 420-540° C., preferably 420-450° C.; a pressure of 3.6-6.2 MPa, preferably 3.6-4.0 MPa; a hydrogen partial pressure of 2.52-5.58 MPa, preferably 2.52-3.0 MPa; and a hydrogen-to-oil volume ratio of (3.0-4.0):1, preferably (3.0-3.5):1.

[0042] In one embodiment, before the toluene component is returned to the aromatic dealkylation unit 6, the toluene component is mixed with an external toluene component, wherein the weight ratio of the external toluene component to the toluene component is not fixed and is determined according to the scale of the dealkylation unit.

[0043] In one embodiment, the conditions for the aromatics extraction treatment include: a temperature of 89-175° C., preferably 121-168° C.; a pressure of 0.08-0.1 MPa, preferably 0.08 MPa; and a stripping medium of sulfolane solvent.

[0044] In one embodiment, the reformed hydrogen further includes third reformed hydrogen, and the third reformed hydrogen is sent to other hydrogen-using devices; the method further includes mixing the second portion of reformed hydrogen with purchased hydrogen and then entering the aromatic dealkylation device 6.

[0045] In this embodiment, the first part of the reformed hydrogen and the second part of the reformed hydrogen are preferentially used. Since the first part of the reformed hydrogen and the second part of the reformed hydrogen are respectively supplied to the pre-hydrogenation device and the aromatic dealkylation device, the amount of the first part of the reformed hydrogen and the second part of the reformed hydrogen is determined according to the scale of the specific device. This application does not make special requirements and only needs to meet the hydrogen requirements of the pre-hydrogenation reaction and the dealkylation treatment. The third part of the reformed hydrogen is related to the amount of the first part of the reformed hydrogen and the second part of the reformed hydrogen. If the feed scale is large, the consumption of the first part of the reformed hydrogen and the second part of the reformed hydrogen is large, and the amount of the third part of the reformed hydrogen, i.e., the remaining hydrogen from the reforming, is small, or there may even be no remaining third part of the reformed hydrogen. In this case, it is necessary to add purchased hydrogen.

[0046] In one embodiment, Figure 1 As shown, the combined process method for producing more benzene includes:

[0047] S1. Feedstock 104 composed of straight-run heavy naphtha 100, steam cracking raffinate 101, catalytic cracking raffinate 102, and other hydrogenated naphtha enters pre-hydrogenation unit 1 for pre-hydrogenation reaction to obtain pre-hydrogenation reaction product 105; the pre-hydrogenation reaction conditions include: reaction temperature of 280-340° C., reaction pressure of 2.8-3.8 MPa, hydrogen partial pressure of 2.16-3.42 MPa, and a volume ratio of the first portion of reformed hydrogen 201 to the feedstock 104 of (90-100):1.

[0048] S2, a portion of the pre-hydrogenation reaction product 105 enters the first naphtha separation device 2 for first separation, to obtain C 6-7 Naphtha 106 and C 7+ Naphtha 111; the separation requirement for the first separation is C 6-7 Naphtha 106 C 8+ The component content is below 0.1 wt%.

[0049] S3, make C 6-7 The mixed aromatization feed 107 obtained by mixing naphtha 106 and non-aromatic raffinate 116 enters the alkane aromatization unit 3 for alkane aromatization reaction to obtain the first benzene-rich aromatics 108 and aromatized hydrogen 203; wherein, the reaction temperature of the alkane aromatization reaction is 450-530°C, the reaction pressure is 0.3-1.0 MPa, and the reaction mass space velocity is 1.0-1.5 h -1 The impurity content of the mixed aromatization feed 107 includes: S < 0.1 ppm, H2O < 1 ppm, N < 0.5 ppm, Pb < 1 ppb, Cu < 1 ppb, As < 1 ppb.

[0050] S4, make the C 7+Naphtha 111 and the remaining pre-hydrogenation reaction product 110 are mixed and then fed into reforming unit 4 for reforming, producing reformate 112 and reformed hydrogen. The reforming process is conducted at a reaction pressure of 0.35 MPa and a reactor inlet temperature of 526-538°C. A first portion of reformed hydrogen 201 enters pre-hydrogenation unit 1, a second portion of reformed hydrogen 202 and purchased hydrogen 207 enter aromatic dealkylation unit 6, and a third portion of reformed hydrogen 206 is delivered to other hydrogen-consuming units.

[0051] S5, the reformed oil 112 enters the second separation device 5, and the reformed oil C is obtained. 6-7 Naphtha 113, C8 aromatics 204, C 9+ Aromatic hydrocarbons 114 and heavy aromatic hydrocarbons 205. The C8 aromatic hydrocarbons 204 and heavy aromatic hydrocarbons 205 are sold as products; the separation requirements of the second separation device 5 include: reforming C 6-7 Naphtha 113 C 8+ The component content is below 0.1 wt%, C 9+ C in aromatic hydrocarbon 114 component 10+ The component is below 2% by weight.

[0052] S6, make the C 9+ Aromatics 114 and foreign C 9+ The components enter the aromatic dealkylation unit 6 for dealkylation to obtain second benzene-rich aromatics 115. The dealkylation conditions include: temperature of 420-540°C, pressure of 3.6-6.2 MPa, hydrogen partial pressure of 2.52-5.58 MPa, and hydrogen-to-oil volume ratio of (3.0-4.0):1.

[0053] S7, making the reforming C 6-7 Naphtha 113, the first benzene-rich aromatics 108 and the second benzene-rich aromatics 115 enter the aromatics extraction unit 7 for aromatics extraction treatment to obtain non-aromatic raffinate 116, a benzene-rich product 117 and a toluene component 118; the toluene component 118 is mixed with the external toluene component 119 and returned to the aromatics dealkylation unit 6.

[0054] The method provided by the present invention is further illustrated below by means of specific examples, but the present invention is not limited thereto.

[0055] Example 1

[0056] like Figure 3 As shown, the combined process method for producing more benzene includes:

[0057] S1. Feedstock 104 composed of straight-run heavy naphtha 100, catalytic cracking raffinate 102, and other hydrogenated naphtha 103 enters pre-hydrogenation unit 1 for pre-hydrogenation reaction with a first portion of reformed hydrogen to obtain a pre-hydrogenation reaction product 105. The pre-hydrogenation reaction conditions include: a reaction temperature of 320° C., a reaction pressure of 2.8 MPa, a hydrogen partial pressure of 2.52 MPa, and a volume ratio of the first portion of reformed hydrogen to the feedstock 104 of 90:1.

[0058] S2, all (100 wt%) of the pre-hydrogenation reaction product 105 enters the first separation device 2 for first separation to obtain C 6-7 Naphtha 106 and C 7+ Naphtha 111; the separation requirement for the first separation is C 6-7 Naphtha 106 C 8+ The component content is below 0.1 wt%.

[0059] S3, make C 6-7 The mixed aromatization feed 107 obtained by mixing naphtha 106 and non-aromatic raffinate 116 enters the alkane aromatization unit 3 for alkane aromatization reaction to obtain the first benzene-rich aromatics 108 and aromatized hydrogen 203; wherein, the reaction temperature of the alkane aromatization reaction is 450°C, the reaction pressure is 0.3 MPa, and the reaction space velocity is 1.5 h -1 The impurity content of the mixed aromatization feed 107 includes: S < 0.1 ppm, H2O < 1 ppm, N < 0.5 ppm, Pb < 1 ppb, Cu < 1 ppb, As < 1 ppb.

[0060] S4, make C 7+ Naphtha 111 enters reformer 4 for reforming, producing reformate 112 and reformed hydrogen. The reforming process operates at a reaction pressure of 0.35 MPa and a reactor inlet temperature of 536°C. A first portion of reformed hydrogen 201 (3.7 wt%) enters pre-hydrogenation unit 1, a second portion of reformed hydrogen 202 (52.2 wt%) enters aromatic dealkylation unit 6, and a third portion of reformed hydrogen 206 (44.1 wt%) is delivered to other hydrogen-using units.

[0061] S5, the reformed oil 112 components enter the second separation device 5, and the reformed C 6-7 Naphtha 113, C8 aromatics 204, C 9+ Aromatics 114 and heavy aromatics 205, C8 aromatics 204 and heavy aromatics 205 are sold as products; the separation requirements of the second separation device 5 include: reforming C 6-7 Naphtha 113 C 8+ The component content is below 0.1 wt%, C 9+ C in aromatics 114 10+ The component is below 2% by weight.

[0062] S6, make C 9+ Aromatics 114 enters aromatic dealkylation unit 6 for dealkylation to obtain second benzene-rich aromatics 115. The dealkylation conditions include: temperature of 420°C, pressure of 3.6 MPa, hydrogen partial pressure of 2.52 MPa, and hydrogen-to-oil volume ratio of 3.0:1.

[0063] S7, reorganize C 6-7 Naphtha 113, the first benzene-rich aromatics 108 and the second benzene-rich aromatics 115 are mixed to obtain mixed aromatics 109, which enters the aromatics extraction unit 7 for aromatics extraction treatment to obtain non-aromatic raffinate 116, benzene-rich product 117 and toluene component 118; the conditions for the aromatics extraction treatment include: temperature of 121°C, pressure of 0.08 MPa, and stripping medium of sulfolane solvent.

[0064] The raw oil and product indicators are shown in Table 1.

[0065] Comparative Example 1

[0066] like Figure 2 As shown, the combined process method for producing more benzene includes:

[0067] S1. Feedstock 104 composed of straight-run heavy naphtha 100, catalytic cracking raffinate 102, and other hydrogenated naphtha 103 is fed into a pre-hydrogenation unit 1 for a pre-hydrogenation reaction to produce a pre-hydrogenation reaction product 110. The pre-hydrogenation reaction conditions include a reaction temperature of 320° C., a reaction pressure of 2.8 MPa, a hydrogen partial pressure of 2.52 MPa, and a volume ratio of the first portion of reformed hydrogen 201 to the pre-hydrogenation reaction product 110 of 90:1. The hydrogen consumption is 0.13 wt%.

[0068] S2, the pre-hydrogenation reaction product 110 enters the reforming unit 4 for reforming reaction to obtain rich reformate 112 and reformed hydrogen. The reaction pressure of the reforming treatment is 0.35MPa, the reactor inlet temperature is 536℃, and the reaction space velocity is 1.5h -1 The first part of the reformed hydrogen 201 (3.23 wt%) enters the pre-hydrogenation unit 1, and the second part of the reformed hydrogen 202 (96.77 wt%) and the purchased hydrogen 207 enter the aromatic dealkylation unit 6. The shortage of 10,000 tons of hydrogen per year is supplemented by the purchased hydrogen 207.

[0069] S3, the reformed oil 112 enters the second separation device 5, and the reformed C 6-7 Naphtha 113, C8 aromatics 204, C 9+ Aromatics 114 and heavy aromatics 205, C8 aromatics 204 and heavy aromatics 205 are sold as products; the separation requirements of the second separation device 5 include: reforming C 6-7 Naphtha 113 C8+ The component content is below 0.1 wt%, C 9+ C in aromatics 114 10+ The component is below 2w%.

[0070] S4, make C 9+ Aromatics 114 enters aromatic dealkylation unit 6 for dealkylation to obtain second benzene-rich aromatics 115. The dealkylation conditions include: temperature of 420°C, pressure of 3.6 MPa, hydrogen partial pressure of 2.52 MPa, and hydrogen-to-oil volume ratio of 3.0:1.

[0071] S5, reorganize C 6-7 Naphtha 113 and second benzene-rich aromatics 115 enter the aromatics extraction unit 7 for aromatics extraction treatment to obtain non-aromatic raffinate 116, benzene-rich product 117 and toluene component 118; the toluene component 118 is returned to the aromatics dealkylation unit 6; the conditions for the aromatics extraction treatment include: temperature of 121°C, pressure of 0.08 MPa, and a stripping medium of sulfolane solvent.

[0072] The raw oil and product indicators are shown in Table 1.

[0073] Table 1: Raw oil and product indicators in Examples and Comparative Examples

[0074]

[0075] As shown in Table 1, Example 1 and Comparative Example 1 produce the same amount of benzene-rich product, both meeting the target product requirements. Example 1 saves 26,000 tons / year of hydrogen consumption compared to Comparative Example 1, and produces 433,500 tons / year more toluene and 378,700 tons / year less naphtha in the product.

[0076] Test Case

[0077] In the economic analysis, the price of crude oil and products is calculated using two price systems: the benefit calculation price of US$60 (referred to as Sinopec US$60) and the average price of Sinopec from 2017 to 2019 (referred to as average price) of the "Technical and Economic Parameters and Data for Feasibility Studies of Petrochemical Projects in China (2020)" by the Economic Research Institute. The construction investment of Example 1 and Comparative Example 1 is equivalent. Therefore, the economic analysis does not take into account the impact of investment cost. The operating cost of the device only includes the cost of utility works of the device, and does not include the cost of catalyst and auxiliary material consumption. Among them, "+" indicates an increase compared to the benchmark value, and "-" indicates a decrease compared to the benchmark value. For example, "+26751" in Table 2 refers to an increase of 267.51 million yuan in the product output value of Example 1 compared to the benchmark value of Comparative Example 1.

[0078] The economic comparison results of Example 1 and Comparative Example 1 are listed in Tables 2 and 3. According to Table 2, under Sinopec's $60 price system, the gross profit of Example 1 increased by 426.88 million yuan / year compared with Comparative Example 1, and under Sinopec's average price from 2017 to 2019, the gross profit increased by 468.68 million yuan / year compared with Comparative Example 1.

[0079] Table 2 Economic comparison results of Example 1 and Comparative Example 1 (Sinopec USD 60)

[0080] name unit Example 1 Comparative Example 1 Product output value 10,000 yuan / year +26751 Benchmark Raw material costs 10,000 yuan / year -30311 Benchmark Operating costs 10,000 yuan / year +14374 Benchmark gross profit 10,000 yuan / year 42688 Benchmark

[0081] Table 3 Economic comparison results of Example 1 and Comparative Example 1 (average price from 2017 to 2019)

[0082] name unit Example 1 Comparative Example 1 Product output value 10,000 yuan / year +35356 Benchmark Raw material costs 10,000 yuan / year -25886 Benchmark Operating costs Ten thousand yuan / +14374 Benchmark gross profit 10,000 yuan / year 46868 Benchmark

[0083] As shown in Tables 1 to 3, based on the comparison of the data of Example 1 and Comparative Example 1, it can be seen that the technical solution of the present disclosure can increase the yield of toluene while reducing the amount of hydrogen used and the output of naphtha; moreover, the technical solution of the present disclosure can not only reduce the cost of raw materials, but also increase the output value of products, showing good economic benefits.

[0084] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0086] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for producing high-yield benzene by combined processing, characterized in that: The method includes: The crude oil is fed into a pre-hydrogenation device for pre-hydrogenation reaction to obtain a pre-hydrogenation reaction product, and at least a portion of the pre-hydrogenation reaction product is subjected to a first separation to obtain C 6-7 Naphtha and C 7+ Naphtha; the raw oil is selected from oil products with an initial boiling point of 60~70℃ and a final boiling point of 170~180℃; Make the C 6-7 The naphtha enters the alkane aromatization unit for aromatization reaction to obtain aromatized hydrogen and the first benzene-rich aromatics; Make the C 7+ The naphtha enters the reforming unit for reforming treatment to obtain reformed hydrogen and reformed oil; the reformed oil is subjected to a second separation to obtain reformed C 6-7 Naphtha, C8 aromatics, C 9+ Aromatics and heavy aromatics; Make the C 9+ The aromatics enter the aromatics dealkylation unit for dealkylation to obtain the second benzene-rich aromatics; The first benzene-rich aromatics and the reformed C 6-7 The naphtha and the second benzene-rich aromatics enter the aromatics extraction unit for aromatics extraction treatment to obtain non-aromatic raffinate oil, benzene-rich product and toluene component; The non-aromatic raffinate is returned to the alkane aromatization unit, and the toluene component is returned to the aromatic dealkylation unit; the reformed hydrogen is divided into at least a first portion of reformed hydrogen and a second portion of reformed hydrogen, the first portion of reformed hydrogen enters the pre-hydrogenation unit, and the second portion of reformed hydrogen enters the aromatic dealkylation unit; The reaction conditions of the pre-hydrogenation reaction include: a reaction temperature of 280-340° C., a reaction pressure of 2.4-3.8 MPa, a hydrogen partial pressure of 2.16-3.42 MPa, and a volume ratio of the first portion of reformed hydrogen to the feedstock oil of (90-100):1; The aromatization reaction conditions include: a reaction temperature of 450-530° C., a reaction pressure of 0.3-1.0 MPa, and a reaction mass space velocity of 1.0-1.5 h -1 ; The dealkylation treatment conditions include: temperature of 420-540° C., pressure of 3.6-6.2 MPa, hydrogen partial pressure of 2.52-5.58 MPa, and hydrogen-to-oil volume ratio of (3.0-4.0):

1.

2. The method according to claim 1, characterized in that The raw oil is selected from one or more of straight-run heavy naphtha, steam cracking raffinate oil, catalytic cracking raffinate oil and hydrogenated naphtha.

3. The method according to claim 1, characterized in that The catalyst used in the pre-hydrogenation reaction includes RS-1 catalyst or S-125 catalyst.

4. The method according to claim 1, wherein The catalyst used in the aromatization reaction is PL-90 catalyst.

5. The method according to claim 1, characterized in that The C 6-7 C in naphtha 8+ The content of the components is below 0.1 wt %, the sulfur content in the mixed aromatization feed is below 0.1 ppm, and the water content is below 1 ppm.

6. The method according to claim 1, wherein Before the dealkylation treatment, the foreign C 9+ Components and the C 9+ Aromatic mixture.

7. The method according to claim 1, characterized in that The reformed hydrogen also includes third reformed hydrogen, and the third reformed hydrogen is sent to other hydrogen-using devices.

8. The method according to claim 1, characterized in that The method further includes mixing the second portion of reformed hydrogen with externally purchased hydrogen and then introducing the mixture into the aromatic dealkylation unit.

9. The method according to claim 1, characterized in that The method further comprises: mixing a portion of the pre-hydrogenation reaction product with the C 7+ The mixed naphtha obtained after the naphtha is mixed enters the reforming device.

10. The method according to claim 1, characterized in that The reforming C 6-7 C in naphtha 8+ The content of the component is less than 0.1% by weight; The C 9+ C in aromatics 10+ The content of the component is below 2% by weight.

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