Diesel hydrocracking reaction system and control method

Abstract

The invention discloses a diesel hydrocracking reaction system and a control method. The system comprises a hydrocracking reactor and a heat exchanger unit which are communicated with each other, a partition plate is arranged in the hydrocracking reactor and divides a reaction zone of the hydrocracking reactor into a first reaction zone and a second reaction zone; a plurality of fixed bed layers are sequentially arranged in the first reaction zone and the second reaction zone from top to bottom at intervals, and a built-in micro-interface generator is arranged between every two adjacent fixed bed layers; and the hydrocracking reactor is also connected with a cracking micro-interface unit. The hydrocracking reactor is divided into the first reaction zone and the second reaction zone, and the built-in micro-interface generator is arranged, so that the mass transfer effect and the reaction efficiency between two phases are improved, the consumption of hydrogen is reduced, the reaction temperature and pressure are reduced, the high efficiency of the reaction is ensured, the cost is low, and the problems of high energy consumption and low energy consumption in the prior art are solved. The pressure and the temperature required by the hydrocracking reaction are too high, and the productivity is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel hydrocracking, and particularly relates to a reaction system and a control method for diesel hydrocracking. Background Art

[0002] Hydrocracking has developed into one of the most important catalytic processing processes in today's refining and petrochemical industries. Heavy petroleum fractions, including straight-run fractions, catalytic cracking recycle oil, and coking distillate oil, etc., in the presence of hydrogen and bifunctional catalysts, through hydrocracking reactions, can not only produce high-quality light oil products (such as jet fuel, low-freezing-point diesel), but also provide high-quality feedstocks for various processes (such as catalytic cracking, steam cracking, and catalytic reforming, etc.).

[0003] However, in the existing diesel hydrocracking reaction systems, a two-stage hydrotreating process of hydrofining, hydrocracking or a combination of both is adopted. Although the hydrotreating process is easy to operate and industrialize, it has high energy consumption, high hydrocracking reaction pressure, high temperature, and relatively low production capacity.

[0004] Therefore, in order to solve the above problems, there is an urgent need to develop a new reaction system or method for diesel hydrocracking. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a reaction system and a control method for diesel hydrocracking that can overcome or at least partially solve the above problems.

[0006] In a first aspect, the present invention provides a reaction system for diesel hydrocracking, the reaction system for diesel hydrocracking comprising: a hydrocracking reactor and a heat exchanger unit that are interconnected;

[0007] A partition is provided inside the hydrocracking reactor, and the reaction zone of the hydrocracking reactor is divided into a first reaction zone and a second reaction zone by the partition; a plurality of fixed bed layers are sequentially arranged at intervals from top to bottom in both the first reaction zone and the second reaction zone, and an internal micro interface generator is arranged between adjacent fixed bed layers;

[0008] The hydrocracking reactor is further connected with a cracking micro interface unit for crushing and dispersing hydrogen before it enters the hydrocracking reactor;

[0009] A cracking product outlet is provided at the top of the hydrocracking reactor, the cracking product outlet is communicated with the heat exchanger unit, and the cracking reaction product of the hydrocracking reactor exchanges heat with the raw material entering the hydrocracking reactor through the heat exchanger unit; the heat exchanger unit is communicated with the cracking micro interface unit.

[0010] Optionally, the spacing distance between adjacent fixed bed layers in the first reaction zone is less than that between adjacent fixed bed layers in the second reaction zone.

[0011] Optionally, the built-in micro interface generators in the first reaction zone are respectively arranged at the top end of the uppermost fixed bed layer and the bottom end of the lowermost fixed bed layer in the first reaction zone.

[0012] Optionally, the built-in micro interface generators in the second reaction zone are arranged between adjacent fixed bed layers, and the built-in micro interface generators in the second reaction zone are staggered in the vertical direction.

[0013] Optionally, the heat exchanger unit is further connected with a preheating micro interface unit and a hot high-pressure separator. The preheating micro interface unit is communicated with a feed pump, and the feed pump is communicated with a feed oil inlet.

[0014] Optionally, the preheating micro interface unit includes a first preheating micro interface generator and a second preheating micro interface generator arranged in parallel. The first preheating micro interface generator is arranged below the second preheating micro interface generator, and the outlets of the first preheating micro interface generator and the second preheating micro interface generator are arranged opposite to each other.

[0015] Optionally, a counterflush pipeline is arranged between the first preheating micro interface generator and the second preheating micro interface generator. The counterflush pipeline is communicated with the heat exchanger feed inlet of the heat exchanger unit; distribution plates are respectively connected to the outlets of the first preheating micro interface generator and the second preheating micro interface generator.

[0016] Optionally, a hydrogen mixing filter is further included. The hydrogen mixing filter is communicated with a hydrogen mixing heat exchanger. The hydrogen mixing heat exchanger is respectively communicated with the cracking micro interface unit, the preheating micro interface unit and the hot high-pressure separator. The hydrogen mixing filter is communicated with a hydrogen inlet pipeline, and the separator feed inlet of the hot high-pressure separator is communicated with the heat exchanger product outlet of the heat exchanger unit.

[0017] Optionally, a reaction feed heating furnace is further arranged between the hydrocracking reactor and the heat exchanger unit. The inlet of the reaction feed heating furnace is communicated with the heat exchanger feed outlet of the heat exchanger unit, and the outlet of the reaction feed heating furnace is communicated with the hydrocracking reactor.

[0018] In a second aspect, the present invention provides a control method for a reaction system of diesel hydrocracking, including:

[0019] Connect the hydrocracking reactor and the heat exchanger unit to each other. A cracking product outlet is provided at the top of the hydrocracking reactor, and the cracking product outlet is connected to the heat exchanger unit. The cracking reaction products in the hydrocracking reactor are heat-exchanged with the raw materials entering the hydrocracking reactor through the heat exchanger unit. Among them, the pressure of the reaction in the hydrocracking reactor is 0.5 - 1.0 MPa, and the reaction temperature is 255 - 275 °C;

[0020] A cracking microinterface unit is connected to the hydrocracking reactor, and a preheating microinterface unit and a hot high-pressure separator are connected to the heat exchanger unit. The heat exchanger unit is connected to the cracking microinterface unit to break and disperse hydrogen before it enters the hydrocracking reactor;

[0021] A partition plate is arranged inside the hydrocracking reactor. The reaction area of the hydrocracking reactor is divided into a first reaction area and a second reaction area by the partition plate. A plurality of fixed bed layers are sequentially arranged at intervals from top to bottom in both the first reaction area and the second reaction area, and an internal microinterface generator is arranged between adjacent fixed bed layers. Among them, the interval distance between adjacent fixed bed layers in the first reaction area is less than the interval distance between adjacent fixed bed layers in the second reaction area;

[0022] The internal microinterface generators in the first reaction area are respectively arranged at the top of the uppermost fixed bed layer and the bottom of the lowermost fixed bed layer in the first reaction area;

[0023] The internal microinterface generators in the second reaction area are arranged between adjacent fixed bed layers, and the internal microinterface generators in the second reaction area are staggered in the vertical direction;

[0024] Before hydrogen enters the cracking reactor, hydrogen and diesel are first broken and dispersed into micron-sized bubbles by the preheating microinterface unit, and then the diesel and hydrogen are preheated by the heat exchanger unit and enter the cracking microinterface unit for further breaking and dispersing, and then enter the first reaction area and the second reaction area in sequence for cracking reaction. Finally, the reaction products are heat-exchanged by the heat exchanger unit and then transported to the hot high-pressure separator for further separation.

[0025] The technical solution provided in the embodiments of the present invention has at least the following technical effects or advantages:

[0026] An embodiment of the present invention provides a reaction system and a control method for diesel hydrocracking. In the reaction system for diesel hydrocracking according to the embodiment of the present invention, the interior of the hydrocracking reactor is divided into a first reaction zone and a second reaction zone. By setting an internal microinterface generator, the mass transfer effect and reaction efficiency between two phases are improved. The gas can be broken into micron-sized bubbles, thereby increasing the phase boundary mass transfer area between the gas phase and the liquid phase, making the mass transfer space fully satisfied, increasing the residence time of hydrogen in diesel, thus reducing the consumption of hydrogen. This not only reduces the reaction temperature and pressure, but also ensures the high efficiency of the reaction itself, avoids a series of safety hazards caused by high temperature and high pressure, is more conducive to energy conservation and consumption reduction in the reaction process, has low cost, and solves the problems of high energy consumption, too high pressure and temperature required for hydrocracking reaction, and low production capacity in the prior art.

[0027] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are hereinafter specifically exemplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components.

[0029] In the drawings:

[0030] Figure 1 is a schematic diagram of the principle structure of a reaction system for diesel hydrocracking provided by an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the principle structure of a reaction system for diesel hydrocracking provided by another embodiment of the present invention.

[0032] DESCRIPTION OF THE REFERENCE NUMERALS

[0033] 1, hydrocracking reactor; 2, first reaction zone; 3, second reaction zone; 4, partition board; 5, fixed bed layer; 6, internal microinterface generator; 7, preheating microinterface unit; 701, first preheating microinterface generator; 702, second preheating microinterface generator; 8, cracking microinterface unit; 9, cracking product outlet; 10, hot high-pressure separator; 11, heat exchanger unit; 12, heat exchanger product outlet; 13, separator feed inlet; 14, heat exchanger feedstock inlet; 15, heat exchanger feedstock outlet; 16, counterflush pipeline; 17, distribution plate; 18, hydrogen inlet pipeline; 19, hydrogen mixing filter; 20, reaction feed heating furnace; 21, hydrogen mixing heat exchanger. Detailed implementation manners

[0034] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0035] Schematic structural diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0036] In the context of the present disclosure, when a layer / component is referred to as being "on" another layer / component, the layer / component may be directly on the other layer / component, or there may be an intermediate layer / component between them. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component may be "under" the other layer / component. In the context of the present disclosure, similar or identical components may be represented by the same or similar reference numerals.

[0037] To better understand the above technical solutions, the above technical solutions will be described in detail below in combination with specific implementation manners. It should be understood that the embodiments of the present disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments may be combined with each other.

[0038] Figure 1 is a schematic diagram of the principle structure of a reaction system for diesel hydrocracking provided by an embodiment of the present invention, as Figure 1 shown, the reaction system for diesel hydrocracking includes: a hydrocracking reactor 1 and a heat exchanger unit 11 that are interconnected;

[0039] A partition plate 4 is disposed inside the hydrocracking reactor 1, and the partition plate 4 divides the reaction zone of the hydrocracking reactor 1 into a first reaction zone 2 and a second reaction zone 3; a plurality of fixed bed layers 5 are sequentially arranged at intervals from top to bottom in both the first reaction zone 2 and the second reaction zone 3, and an internal microinterface generator 6 is disposed between adjacent fixed bed layers 5;

[0040] The hydrocracking reactor 1 is further connected with a cracking microinterface unit 8 for crushing and dispersing hydrogen before it enters the hydrocracking reactor 1;

[0041] The top of the hydrocracking reactor 1 is provided with a cracking product outlet 9, and the cracking product outlet 9 is communicated with the heat exchanger unit 11. The cracking reaction products of the hydrocracking reactor 1 are heat-exchanged with the raw materials entering the hydrocracking reactor 1 through the heat exchanger unit 11; the heat exchanger unit 11 is communicated with the cracking microinterface unit 8.

[0042] In the reaction system of diesel hydrocracking according to the embodiment of the present invention, the interior of the hydrocracking reactor 1 is divided into a first reaction zone 2 and a second reaction zone 3. By arranging an internal microinterface generator 6, the mass transfer effect and reaction efficiency between two phases are improved. The gas can be broken into micron-sized bubbles, thereby increasing the phase boundary mass transfer area between the gas phase and the liquid phase, making the mass transfer space fully satisfied, increasing the residence time of hydrogen in diesel, thereby reducing the consumption of hydrogen. This not only reduces the reaction temperature and pressure, but also ensures the high efficiency of the reaction itself, avoids a series of safety hazards caused by high temperature and high pressure, is more conducive to energy conservation and consumption reduction in the reaction process, has low cost, and solves the problems of high energy consumption, too high pressure and temperature required for hydrocracking reaction, and low production capacity in the prior art.

[0043] In the embodiment of the present invention, the partition 4 is arranged in the middle area of the hydrocracking reactor 1. By being arranged horizontally, the hydrocracking reactor 1 is divided into two regions up and down, namely the first reaction zone 2 and the second reaction zone 3. A plurality of fixed bed layers 5 are sequentially arranged at intervals from top to bottom in the first reaction zone 2 and the second reaction zone 3, and an internal microinterface generator 6 is arranged between adjacent fixed bed layers 5, so that independent reactions can be realized in the two regions respectively.

[0044] Since the uses of the first reaction zone 2 and the second reaction zone 3 are not completely the same, in the embodiment of the present invention, optionally, the interval distance between adjacent fixed bed layers 5 in the first reaction zone 2 is smaller than the interval distance between adjacent fixed bed layers 5 in the second reaction zone 3. Adjusting the interval distance of the fixed bed layers 5 is to facilitate the subsequent installation and placement of the corresponding internal microinterface generator 6.

[0045] Optionally, the built-in microinterface generators 6 in the first reaction zone 2 are respectively arranged at the top end of the fixed bed layer 5 at the uppermost layer and the bottom end of the fixed bed layer 5 at the lowermost layer in the first reaction zone 2. For example, in the embodiment of the present invention, one built-in microinterface generator 6 is arranged at the top end of the fixed bed layer 5 at the uppermost layer in the first reaction zone 2, and one built-in microinterface generator 6 is arranged at the bottom end of the fixed bed layer 5 at the lowermost layer in the first reaction zone 2. In other embodiments of the present invention, it may also be other setting quantities. For example, multiple built-in microinterface generators 6 may be arranged at the top end of the fixed bed layer 5 at the uppermost layer in the first reaction zone 2 or no built-in microinterface generator 6 may be arranged, and multiple built-in microinterface generators 6 are arranged at the bottom end of the fixed bed layer 5 at the lowermost layer in the first reaction zone 2, which can be flexibly switched according to the operating state of the unit, as long as at least one built-in microinterface generator 6 is ensured to be arranged at the bottom end of the fixed bed layer 5 at the lowermost layer in the first reaction zone 2.

[0046] Optionally, the built-in microinterface generators 6 in the second reaction zone 3 are arranged between adjacent fixed bed layers 5, and the built-in microinterface generators 6 in the second reaction zone 3 are staggered in the vertical direction.

[0047] Specifically, during the hydrocracking reaction process, a catalyst needs to be added into the fixed bed layer 5 of the hydrocracking reactor 1. In order to achieve sufficient contact between the catalyst and the feedstock oil and hydrogen, for example, a first catalyst is added into the first reaction zone 2 to perform a primary hydrocracking reaction on the feedstock oil in the first reaction zone 2. For the primary hydrocracking reaction, only the feedstock oil and hydrogen entering the inside of the first reaction zone 2 need to be broken and dispersed into microbubbles with a diameter greater than or equal to 1 μm and less than 1 mm, and then mixed with the first catalyst in the fixed bed layer 5, and enter the second reaction zone 3 by means of overflow. The second reaction zone 3 is a strengthened cracking reaction zone. Based on this, the built-in microinterface generators 6 in the second reaction zone 3 are arranged in a staggered manner, and a built-in microinterface generator 6 is arranged between each layer of the fixed bed layer 5. Since the second reaction zone 3 is a strengthened cracking reaction zone, it is necessary to continuously break the mixed material entering the second reaction zone 3. At the same time, according to the high-speed jet principle of the microinterface generator, the microbubbles in the built-in microinterface generator are ejected to stir the liquid in the second reaction zone 3.

[0048] Wherein, the pressure of the reaction in the hydrocracking reactor 1 is 0.5 - 1.0 MPa, and the temperature of the reaction is 255 - 275 °C.

[0049] In the embodiment of the present invention, the volumes of the first reaction zone 2 and the second reaction zone 3 separated by the partition plate 4 are the same. In other embodiments, the setting position of the partition plate 4 can also be adjusted, so as to correspondingly adjust the volumes of the first reaction zone 2 and the second reaction zone 3. It can be selected according to actual needs, and the intake air volume can be flexibly switched and adjusted for different working conditions. The embodiment of the present invention has no limitation on this.

[0050] Optionally, the heat exchanger unit 11 is further connected with a preheating microinterface unit 7 and a thermal high-pressure separator 10. The preheating microinterface unit 7 is communicated with a raw material pump, and the raw material pump is communicated with a raw material oil inlet. In the embodiment of the present invention, hydrogen and raw material oil are broken and dispersed before entering the heat exchanger unit 11. By combining the heat exchanger unit 11 with the preheating microinterface unit 7, the raw material oil and hydrogen can be preliminarily mixed and evenly enter the interior of the heat exchanger unit 11, so as to effectively achieve heat exchange. By preliminarily mixing the raw material oil and hydrogen, the temperature gradient thereof can be eliminated, and it is ensured that the raw material oil and hydrogen enter the heat exchanger unit 11 evenly, thereby improving the heat exchange efficiency and quality. In addition, mixing the raw material oil and hydrogen can avoid local overheating, thereby reducing the risk of equipment damage or production failure caused by high temperature.

[0051] Optionally, the preheating microinterface unit 7 includes a first preheating microinterface generator 701 and a second preheating microinterface generator 702 arranged in parallel. The first preheating microinterface generator 701 is arranged below the second preheating microinterface generator 702, and the outlets of the first preheating microinterface generator 701 and the second preheating microinterface generator 702 are arranged opposite to each other.

[0052] It should be noted that in the embodiment of the present invention, the cracking microinterface unit 8, the built-in microinterface generator 6, the first preheating microinterface generator 701 and the second preheating microinterface generator 702 have the same structure and are all microinterface generators with the same function. The specific working principle of the microinterface generator is as follows: the liquid tangentially enters the microinterface generator through the liquid inlet pipe, rotates at a super high speed and cuts the gas, so that the gas bubbles are broken into microbubbles at the micron level, thereby increasing the mass transfer area between the liquid phase and the gas phase. The specific product structure and working principle of the microinterface generator refer to the micron bubble generator in the prior art such as CN201610641119.6 (i.e., the microinterface generator in the embodiment of the present invention), and the present invention will not elaborate herein.

[0053] In other embodiments of the present invention, other numbers of microinterface generators can also be set as needed. In order to increase the dispersion and mass transfer effects, additional microinterface generators can also be added. The embodiment of the present invention has no limitation on this.

[0054] Optionally, a counter-flow pipeline 16 is provided between the first preheating micro interface generator 701 and the second preheating micro interface generator 702, and the counter-flow pipeline 16 communicates with the heat exchanger feedstock inlet 14 of the heat exchanger unit 11; by arranging the outlets of the first preheating micro interface generator 701 and the second preheating micro interface generator 702 opposite to each other in pairs, in practical applications, the two groups of opposite micro interface generators are arranged one above the other. The micro interface generator located above allows the raw material oil to flow from top to bottom, and the micro interface generator located below disperses and breaks hydrogen into microbubbles to fully contact the raw material oil from bottom to top. By using the counter-flow pipeline 16 in cooperation with the micro interface generator, power is added to the bubbles, thereby increasing the phase boundary mass transfer area between the raw material oil and hydrogen and improving the utilization rate of hydrogen.

[0055] Distribution plates 17 are respectively connected to the outlets of the first preheating micro interface generator 701 and the second preheating micro interface generator 702. The distribution plates 17 are used to evenly distribute the raw material oil and hydrogen inside the counter-flow pipeline 16. By combining the micro interface generator with the distribution plates 17, the crushing and dispersion effect of the micro interface generator itself is further enhanced. At the same time, the distribution plates 17 evenly distribute the hydrogen and raw material oil flowing out of the micro interface generator inside the counter-flow pipeline 16, realizing the uniform mixing of hydrogen and raw material oil and improving the utilization rate of hydrogen.

[0056] Optionally, a hydrogen mixing filter 19 is further included. The hydrogen mixing filter 19 communicates with a hydrogen mixing heat exchanger 21. The hydrogen mixing heat exchanger 21 communicates with the cracking micro interface unit 8, the preheating micro interface unit 7, and the hot high-pressure separator 10 respectively. The hydrogen mixing filter 19 is connected to a hydrogen inlet pipeline 18. The hydrogen mixing filter 19 introduces raw material hydrogen through the hydrogen inlet pipeline 18 and transports it to the cracking micro interface unit 8 and the preheating micro interface unit 7 respectively after heat exchange through the hydrogen mixing heat exchanger 21.

[0057] The separator feed inlet 13 of the hot high-pressure separator 10 communicates with the heat exchanger product outlet 12 of the heat exchanger unit 11. The high-pressure gas at the top of the hot high-pressure separator 10 is connected to the catalytic system through the hydrogen mixing heat exchanger 21 and transported to the high-pressure gas outlet. The bottom of the hot high-pressure separator 10 is connected to the low-pressure separator and transported to the low-pressure oil outlet. The hot high-pressure separator 10 transfers heat to the transmission pipeline of the hydrogen mixing filter 19 through the hydrogen mixing heat exchanger 21.

[0058] Optionally, a reaction feed heating furnace 20 is further provided between the hydrocracking reactor 1 and the heat exchanger unit 11. The inlet of the reaction feed heating furnace 20 communicates with the heat exchanger feedstock outlet 15 of the heat exchanger unit 11, and the outlet of the reaction feed heating furnace 20 communicates with the hydrocracking reactor 1. The reaction feed heating furnace 20 is used to provide a heating effect and heat the reaction raw materials to the reaction temperature.

[0059] Example 2

[0060] Refer to Figure 2 as shown Figure 2 which is a schematic diagram of the principle structure of a reaction system for diesel hydrocracking provided by another embodiment of the present invention. The difference between this embodiment and Embodiment 1 is that the built-in microinterface generator 6 in the second reaction zone 3 is arranged linearly in the vertical direction.

[0061] Comparative Example 1

[0062] The difference between this example and Embodiment 1 is that the built-in microinterface generator 6 is not provided in the hydrocracking reactor 1.

[0063] Comparative Example 2

[0064] The difference between this example and Embodiment 1 is that the distribution plate 17 is not provided in the preheating microinterface unit 7.

[0065] Comparative Example 3

[0066] In this example, the prior art is adopted, and straight-run diesel and hydrogen are directly introduced into the hydrocracking reactor 1 for cracking reaction treatment.

[0067] Experimental Example 1

[0068] Taking straight-run diesel with a sulfur content of 120 ppm as an example, the hydrocracking reactions were carried out respectively using the reaction systems for diesel hydrocracking of the above-mentioned Embodiments 1-2 and Comparative Examples 1-2. The temperature and pressure at which the reaction products reached the optimal value during the heating and pressurization process were recorded, and the sulfur content in the products was obtained. The experimental data results are shown in Table 1 below for reference.

[0069] Table 1 Experimental Results

[0070] Reaction temperature Reaction pressure Sulfur content after reaction Sulfur removal rate Example 1 255℃ 0.5MPa 1.2ppm 99％ Example 2 265℃ 1.1MPa 20.4ppm 83％ Comparative Example 1 350℃ 1.5MPa 16.8ppm 86％ Comparative Example 2 410℃ 2.6MPa 30.5ppm 74.6％ Comparative Example 3 450℃ 4MPa 51.6ppm 57％

[0071] As can be seen from Table 1, Embodiment 1 can effectively remove the sulfur content in straight-run diesel and can achieve a sulfur removal rate of 99%.

[0072] It should be noted that the reaction temperature and reaction pressure recorded in the experimental result data of the present invention are the point values of the temperature and pressure at which the best effect is obtained by continuously heating and pressurizing the reaction system during the diesel hydrocracking reaction of the present invention. And during the experiment, based on the optimal temperature and pressure, even if the heating and pressurization operations are carried out again, there will be no more obvious sulfur removal effect.

[0073] By comparing Example 1 and Example 2, it can be found that the reaction temperature and pressure of the reaction thermometer in Example 2 are significantly higher than those in Example 1. At the same time, in the final reaction product, the sulfur content in Example 2 is also higher than that in Example 1. That is to say, the sulfur removal rate in Example 2 is not as good as that in Example 1. This is because the built-in microinterface generator 6 in the second reaction zone 3 of Example 2 is arranged on the same straight line. In the reaction system of diesel hydrocracking in Example 1 of the present invention, the second reaction zone 3 is the main reaction zone, and it is necessary to fully react the reaction materials in the second reaction zone 3. However, when the built-in microinterface generator 6 is arranged on the same straight line, it is impossible to better break, disperse and stir the reaction materials near the peripheral wall of the second reaction zone 3. Therefore, the reaction temperature and pressure in Example 2 also need to be increased to achieve better results. However, it can also be found from the experimental data that even if the reaction system in Example 2 is heated and pressurized, it is difficult to achieve the optimal example of the present invention, that is, the sulfur removal effect in Example 1.

[0074] The reaction system of diesel hydrocracking described in the embodiments of the present invention has the following advantages compared with the prior art:

[0075] 1. By separately arranging a cracking microinterface unit 8 outside the hydrocracking reactor 1, the present invention improves the mass transfer effect and reaction efficiency between two phases. Before entering the hydrocracking reactor 1, diesel and hydrogen are broken and dispersed, and hydrogen and diesel can be broken into micron-sized bubbles, thereby increasing the phase boundary mass transfer area between the gas phase and the liquid phase, making the mass transfer space fully satisfied, reducing the consumption of hydrogen, reducing the reaction temperature and pressure, ensuring the high efficiency of the reaction itself, avoiding a series of safety hazards caused by high temperature and high pressure, being more conducive to energy conservation and consumption reduction in the reaction process, and having low cost;

[0076] 2. By arranging a partition 4 inside the hydrocracking reactor 1 to divide it into a first reaction zone 2 and a second reaction zone 3, and setting different catalysts in the fixed bed layer 5 for reaction, the quality of diesel is improved;

[0077] 3. By arranging built-in microinterface generators 6 in the first reaction zone 2 and the second reaction zone 3, and the built-in microinterface generators 6 in the second reaction zone 3 are staggered in the vertical direction, diesel and hydrogen are further broken and dispersed, increasing the phase boundary mass transfer area between hydrogen and diesel, further improving the mass transfer effect of the reaction interface, and reducing the reaction temperature and pressure;

[0078] 4. Distribution plates 17 are respectively connected to the outlets of the first preheating microinterface generator 701 and the second preheating microinterface generator 702. The distribution plates 17 evenly distribute the hydrogen and raw material oil flowing out of the microinterface generator inside the counterflow pipeline 16, realizing the uniform mixing of hydrogen and raw material oil, and improving the utilization rate of hydrogen;

[0079] 5. The present invention provides a heat exchanger unit 11, which makes full use of the heat generated during the reaction process. The reaction products after the diesel hydrocracking reaction are heat-exchanged with the raw materials just entering the hydrocracking reactor 1 through the heat exchanger unit 11, reducing energy consumption and saving costs, and having good application prospects.

[0080] Based on the above embodiments, the present invention also provides a control method for a reaction system of diesel hydrocracking, including the following steps:

[0081] Connect the hydrocracking reactor 1 and the heat exchanger unit 11 to each other. The top of the hydrocracking reactor 1 is provided with a cracking product outlet 9, and the cracking product outlet 9 is connected to the heat exchanger unit 11. The cracking reaction products in the hydrocracking reactor 1 are heat-exchanged with the raw materials entering the hydrocracking reactor 1 through the heat exchanger unit 11. The pressure of the reaction in the hydrocracking reactor 1 is 0.5 - 1.0 MPa, and the temperature of the reaction is 255 - 275 °C;

[0082] The hydrocracking reactor 1 is connected with a cracking microinterface unit 8, and the heat exchanger unit 11 is connected with a preheating microinterface unit 7 and a hot high-pressure separator 10. The heat exchanger unit 11 is connected to the cracking microinterface unit 8 to break and disperse hydrogen before it enters the hydrocracking reactor 1;

[0083] A partition plate 4 is arranged in the hydrocracking reactor 1. The reaction area of the hydrocracking reactor 1 is divided into a first reaction area 2 and a second reaction area 3 by the partition plate 4. A plurality of fixed bed layers 5 are sequentially arranged at intervals from top to bottom in both the first reaction area 2 and the second reaction area 3, and an internal microinterface generator 6 is arranged between adjacent fixed bed layers 5. Among them, the interval distance between adjacent fixed bed layers 5 in the first reaction area 2 is smaller than the interval distance between adjacent fixed bed layers 5 in the second reaction area 3;

[0084] The internal microinterface generators 6 in the first reaction area 2 are respectively arranged at the top end and the bottom end of the fixed bed layer 5 at the uppermost layer and the lowermost layer in the first reaction area 2;

[0085] The internal microinterface generators 6 in the second reaction area 3 are arranged between adjacent fixed bed layers 5, and the internal microinterface generators 6 in the second reaction area 3 are staggered in the vertical direction;

[0086] Before the hydrogen enters the cracking reactor, the hydrogen and diesel oil are first broken and dispersed into micron-sized bubbles by the preheating microinterface unit 7. After that, the diesel oil and hydrogen are preheated by the heat exchanger unit 11 and then enter the cracking microinterface unit 8 for further breaking and dispersing. Then, they enter the first reaction zone 2 and the second reaction zone 3 in sequence for cracking reactions. Finally, the reaction products are heat-exchanged by the heat exchanger unit 11 and then transported to the hot high-pressure separator 10 for further separation.

[0087] The reaction system for diesel hydrocracking described in the above embodiments can execute the control method of the reaction system for diesel hydrocracking provided by the embodiments of the present invention. The control method of the reaction system for diesel hydrocracking has the corresponding functional components and beneficial effects of the reaction system for diesel hydrocracking described in the above embodiments. For details, please refer to the embodiments of the reaction system for diesel hydrocracking above. The embodiments of the present invention will not be elaborated herein.

[0088] In the specification provided herein, a large number of specific details are set forth. However, it is understood that the embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and technologies have not been shown in detail so as not to obscure the understanding of this specification.

[0089] Similarly, it should be understood that, in order to streamline this disclosure and assist in understanding one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0090] It should be noted that the above embodiments illustrate rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims.

Claims

1. A reaction system for diesel hydrocracking, characterized in that, The reaction system of the diesel hydrocracking includes: a hydrocracking reactor and a heat exchanger unit that are interconnected; The hydrocracking reactor is internally provided with a partition plate, and the partition plate divides the reaction zone of the hydrocracking reactor into a first reaction zone and a second reaction zone; in the first reaction zone and the second reaction zone, a plurality of fixed bed layers are sequentially arranged at intervals from top to bottom, and an internal microinterface generator is arranged between adjacent fixed bed layers; The hydrocracking reactor is also connected with a cracking microinterface unit for crushing and dispersing hydrogen before it enters the hydrocracking reactor; A cracking product outlet is arranged at the top of the hydrocracking reactor, and the cracking product outlet is communicated with the heat exchanger unit. The cracking reaction products of the hydrocracking reactor are heat-exchanged with the raw materials entering the hydrocracking reactor through the heat exchanger unit; the heat exchanger unit is communicated with the cracking microinterface unit.

2. The reaction system for diesel hydrocracking according to claim 1, characterized in that: The interval distance between adjacent fixed bed layers in the first reaction zone is smaller than the interval distance between adjacent fixed bed layers in the second reaction zone.

3. The reaction system for diesel hydrocracking according to claim 2, characterized in that: The internal microinterface generators in the first reaction zone are respectively arranged at the top of the uppermost fixed bed layer and the bottom of the lowermost fixed bed layer in the first reaction zone.

4. The reaction system for diesel hydrocracking according to claim 2, characterized in that: The internal microinterface generators in the second reaction zone are arranged between adjacent fixed bed layers, and the internal microinterface generators in the second reaction zone are staggered in the vertical direction.

5. The reaction system for diesel hydrocracking according to claim 1, characterized in that: The heat exchanger unit is also connected with a preheating microinterface unit and a hot high-pressure separator. The preheating microinterface unit is communicated with a raw material pump, and the raw material pump is communicated with a raw material oil inlet.

6. The reaction system for diesel hydrocracking according to claim 5, characterized in that: The preheating microinterface unit includes a first preheating microinterface generator and a second preheating microinterface generator arranged in parallel. The first preheating microinterface generator is arranged below the second preheating microinterface generator, and the outlets of the first preheating microinterface generator and the second preheating microinterface generator are arranged opposite to each other.

7. The reaction system for diesel hydrocracking according to claim 6, characterized in that: A counterflush pipeline is arranged between the first preheating microinterface generator and the second preheating microinterface generator, and the counterflush pipeline is communicated with the heat exchanger raw material inlet of the heat exchanger unit; distribution plates are respectively connected to the outlets of the first preheating microinterface generator and the second preheating microinterface generator.

8. The reaction system for diesel hydrocracking according to claim 6, characterized in that: It also includes a hydrogen mixing filter. The hydrogen mixing filter is communicated with a hydrogen mixing heat exchanger. The hydrogen mixing heat exchanger is respectively communicated with the cracking microinterface unit, the preheating microinterface unit and the hot high-pressure separator. The hydrogen mixing filter is communicated with a hydrogen inlet pipeline, and the separator feed inlet of the hot high-pressure separator is communicated with the heat exchanger product outlet of the heat exchanger unit.

9. The reaction system for diesel hydrocracking according to claim 1, characterized in that: A reaction feed heating furnace is also arranged between the hydrocracking reactor and the heat exchanger unit. The inlet of the reaction feed heating furnace is communicated with the heat exchanger raw material outlet of the heat exchanger unit, and the outlet of the reaction feed heating furnace is communicated with the hydrocracking reactor.

10. A control method for a reaction system of diesel hydrocracking, which is applied to the reaction system of diesel hydrocracking described in any one of claims 1-9, characterized in that, Including: Connect the hydrocracking reactor and the heat exchanger unit to each other. A cracking product outlet is provided at the top of the hydrocracking reactor, and the cracking product outlet is connected to the heat exchanger unit. The cracking reaction products of the hydrocracking reactor are heat-exchanged with the raw materials entering the hydrocracking reactor through the heat exchanger unit. Among them, the pressure of the reaction in the hydrocracking reactor is 0.5 - 1.0 MPa, and the reaction temperature is 255 - 275 °C; A cracking micro-interface unit is connected to the hydrocracking reactor, and a preheating micro-interface unit and a hot high-pressure separator are connected to the heat exchanger unit. The heat exchanger unit is connected to the cracking micro-interface unit to break and disperse hydrogen before it enters the hydrocracking reactor; A partition is provided inside the hydrocracking reactor. The reaction area of the hydrocracking reactor is divided into a first reaction area and a second reaction area by the partition. A plurality of fixed bed layers are sequentially arranged at intervals from top to bottom in both the first reaction area and the second reaction area, and an internal micro-interface generator is arranged between adjacent fixed bed layers. Among them, the interval distance between adjacent fixed bed layers in the first reaction area is smaller than the interval distance between adjacent fixed bed layers in the second reaction area; The internal micro-interface generators in the first reaction area are respectively arranged at the top of the uppermost fixed bed layer and the bottom of the lowermost fixed bed layer in the first reaction area; The internal micro-interface generators in the second reaction area are arranged between adjacent fixed bed layers, and the internal micro-interface generators in the second reaction area are staggered in the vertical direction; Before hydrogen enters the cracking reactor, hydrogen and diesel are first broken and dispersed into micron-sized bubbles by the preheating micro-interface unit, and then after the diesel and hydrogen are preheated by the heat exchanger unit, they enter the cracking micro-interface unit for further breaking and dispersing, and then enter the first reaction area and the second reaction area in sequence for cracking reaction. Finally, the reaction products are heat-exchanged by the heat exchanger unit and then transported to the hot high-pressure separator for further separation.

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