A medium-low temperature coal tar hydrodistillation reactor and a hydroprocessing system using the reactor

Abstract

The present invention discloses a medium-low temperature coal tar hydrodistillation reactor and a hydroprocessing system. The reactor comprises: a reaction chamber, wherein a transversely penetrating catalyst bed is provided, wherein the catalyst bed has an equivalent diameter-to-height ratio of 3:1 to 6:1; the medium-low temperature coal tar after dehydration and impurity removal is in reverse contact with a preheated hydrogen feed in the catalyst bed to undergo a hydrocracking reaction; a distillation separation chamber, which is arranged at the upper portion of the reaction chamber and communicates with the reaction chamber; the gaseous phase products after the hydrocracking reaction enter the distillation separation chamber under the action of countercurrent hydrogen, and the gaseous phase products are distilled and separated in the distillation separation chamber; a heavy oil tank, which is arranged at the bottom of the reaction chamber and is used to receive the liquid phase products generated by the hydrocracking reaction and partially use them as reflux feed. The present invention can effectively improve the resource utilization of medium-low temperature coal tar and increase the yield of the target product; at the same time, it can effectively reduce the coking and clogging of the catalyst bed and extend the operation cycle of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical hydrogenation reactions, and in particular to a medium- and low-temperature coal tar hydrogenation distillation reactor and a hydrogenation treatment system using the reactor. Background Art

[0002] Coal tar is a liquid product obtained from coal dry distillation and gasification. Based on the cracking temperature, it can be divided into several different products: low-temperature coal tar (450-550°C), medium-temperature coal tar (600-800°C), and high-temperature coal tar (1000°C). The composition and properties of medium- and low-temperature coal tar differ from those of high-temperature coal tar. It contains more saturated hydrocarbons, making it more suitable for the treatment with hydrogen and catalysts to improve its stability and reduce its sulfur and aromatics content, thereby producing clean fuel oil.

[0003] Currently, four major combined hydrogenation technologies have been developed in China to produce clean fuel oil from medium- and low-temperature coal tar: pre-distillation-fixed bed hydrogenation, delayed coking-fixed bed hydrogenation, ebullating bed-fixed bed combined hydrogenation, and suspended bed-fixed bed combined hydrogenation. Fixed-bed hydroprocessing is the most mature, simple to operate, and widely used. In traditional hydrogenation reactions, the fixed-bed aspect ratio (the ratio of the reactor bed's total height to its diameter) is generally selected between 2 and 10 to ensure sufficient contact between the gas and liquid materials and the solid catalyst, achieving the desired reaction depth and efficiency. However, there are also some prominent problems in the fixed-bed hydrogenation reactor during the hydrogenation process. For example, the production of clean fuel oil by fixed-bed hydrogenation of coal tar requires the use of distillation pretreatment technology on the raw materials to optimize the properties of the hydrogenation feed and solve the problem of long-term operation of the fixed-bed hydrogenation unit. The heavy components at the bottom of the pre-distillation tower can only be used as heavy raw oil components, and resource utilization is insufficient; the high oxygen content and high olefin content in the raw materials bring high requirements for the catalyst and easy deactivation problems; in the hydrogenation process, it is hoped to increase the depth of the hydrogenation reaction and accelerate the hydrogenation reaction rate. When the catalyst is the same, extending the reaction time and increasing the reaction temperature are the main methods to achieve this. However, as the reaction time is extended and the reaction temperature is increased, it is not conducive to inhibiting or reducing the condensation reaction of polycyclic aromatic hydrocarbons.

[0004] Therefore, there is an urgent need for a medium- and low-temperature coal tar hydrodistillation reactor and a hydroprocessing system using the reactor, so as to improve the utilization of process technology resources for producing clean fuel oil from medium- and low-temperature coal tar, increase the depth of hydrogenation reaction, and increase the yield of the target product.

[0005] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a medium- and low-temperature coal tar hydrodistillation reactor and a hydroprocessing system using the reactor. By using a hydrodistillation reactor with a relatively large equivalent diameter-to-height ratio, the resource utilization of medium- and low-temperature coal tar can be effectively improved, and the yield of the target product can be increased; at the same time, the coking and clogging of the catalyst bed can be effectively slowed down, and the operation cycle of the device can be extended.

[0007] To achieve the above-mentioned purpose, according to the first aspect of the present invention, a medium-low temperature coal tar hydrodistillation reactor is provided, comprising: a reaction chamber, in which a transversely penetrating catalyst bed is provided, and the equivalent diameter-to-height ratio of the catalyst bed is 3:1 to 6:1; the medium-low temperature coal tar after dehydration and impurity removal is in reverse contact with the preheated hydrogen feed in the catalyst bed to carry out a hydrocracking reaction; a distillation separation chamber, which is arranged at the upper part of the reaction chamber and is connected to the reaction chamber, and the gaseous phase products after the hydrocracking reaction enter the distillation separation chamber under the action of countercurrent hydrogen, and the gaseous phase products are distilled and separated in the distillation separation chamber; a heavy oil tank, which is arranged at the bottom of the reaction chamber, for receiving the liquid phase products generated by the hydrocracking reaction and using part of them as reflux feed.

[0008] Furthermore, in the above technical solution, the reaction chamber can be a horizontal tank structure or an oblate cylindrical tank structure; the horizontal tank is axially arranged along the transverse direction and has heads at both ends; the oblate cylindrical tank is axially arranged along the longitudinal direction.

[0009] Furthermore, in the above technical solution, a hydrogen distribution space is provided under the catalyst bed. When the reaction chamber is a horizontal tank structure, a plurality of hollow partitions are provided in parallel along the vertical direction in the hydrogen distribution space, and hydrogen inlets are provided in the areas separated by the partitions.

[0010] Furthermore, in the above technical solution, the hollow partition may extend upward to the catalyst bed, the partition opening rate below the catalyst bed is preferably less than 70%, and the partition opening rate within the catalyst bed is preferably greater than 50%.

[0011] Furthermore, in the above technical solution, a hydrogen distribution space is provided below the catalyst bed. When the reaction chamber is a flat cylindrical tank structure, a plurality of coaxial annular partitions are provided in the hydrogen distribution space.

[0012] Furthermore, in the above technical solution, a coal tar distribution component may be provided on the upper portion of the catalyst bed to evenly distribute the medium and low temperature coal tar on the catalyst bed.

[0013] Furthermore, in the above technical solution, a liquid redistributor may be provided at the connection between the reaction chamber and the distillation separation chamber, and the liquid redistributor includes: a distribution plate, which is arranged above the coal tar distribution assembly, and the distribution plate has the same shape as the top surface of the catalyst bed, and a plurality of first through holes are evenly provided on the distribution plate, a first overflow ring is provided around the first through hole, and an overflow portion is provided at the outer edge of the distribution plate; a distribution cone, which is arranged at the upper center of the distribution plate, and the distribution cone is provided with a plurality of second through holes, and a second overflow ring is provided around the second through hole.

[0014] Furthermore, in the above technical solution, the porosity of the distribution plate is 5% to 90%, the diameter of the first through hole is 5 mm to 100 mm, and the height of the first overflow ring is 1 mm to 30 mm; the top angle of the distribution cone is greater than 90°, the porosity of the distribution cone is 5% to 80%, and the height of the second overflow ring is 1 mm to 30 mm; the bottom area of ​​the distribution cone is 2% to 15% of the area of ​​the distribution plate, and the area of ​​the distribution plate is 50% to 100% of the top surface area of ​​the catalyst bed.

[0015] Furthermore, in the above technical solution, a serration portion may be provided on the inner side of the first overflow ring, the serration portion is bent downward, and a guide groove is provided on the serration portion.

[0016] Furthermore, in the above technical solution, a porous catalyst may be used in the catalyst bed; and the catalyst carrier is a porous carrier.

[0017] Furthermore, in the above technical solution, the ratio of the cross-sectional area of ​​the distillation separation chamber to that of the reaction chamber is preferably 1:1.2 to 1:10.

[0018] Furthermore, in the above technical solution, the distillation separation chamber may include a mixing section, a separation section and a stabilization section from bottom to top; the lightest component in the gaseous products from the reaction chamber flows out from the top of the distillation separation chamber for use as circulating hydrogen; other light components flow out from the side line in the separation section for hydrogenation refining.

[0019] Furthermore, in the above technical solution, the operating conditions of the coal tar hydrocracking reaction process in the hydrodistillation reactor are as follows: reaction temperature of 300°C to 400°C, reaction pressure of 10MPa to 20MPa, hydrogen-to-oil volume ratio of 200:1 to 800:1, volume space velocity of 0.2h -1 ~2.0h -1 .

[0020] To achieve the above-mentioned purpose, according to the second aspect of the present invention, a hydroprocessing system is provided, which can be applied to any of the aforementioned hydrodistillation reactors; the lightest component separated by the distillation separation chamber flows out from the top of the hydrodistillation reactor, and the hydrogen is recovered after purification by the hydrogen purification system and used as circulating hydrogen; other light components flow out from the side line and enter the hydrorefining reactor, high-pressure separator, low-pressure separator and product fractionation tower in sequence, and are fractionated to obtain naphtha fraction and diesel fraction, and the tail oil is returned to the reaction chamber of the hydrodistillation reactor.

[0021] Furthermore, in the above technical solution, the reaction temperature of the hydrotreating reactor is 320℃~450℃, the reaction pressure is 8MPa~20MPa, the hydrogen-oil volume ratio is 600:1~1200:1, and the volume space velocity is 0.2h -1 ~3.0h -1 .

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The present invention adopts an equivalent diameter-to-height ratio of 3:1 to 6:1, which can greatly increase the material flux through the bed and reduce the residence time of the material and heat in the catalyst bed. At the same time, the generated gaseous products can be quickly carried out of the reactor, and the blockage phenomenon caused by the long residence time of by-products in the bed in traditional reactors will not occur.

[0024] 2) While pre-distilling coal tar using the hydrodistillation reactor of the present invention, the heavy oil fraction is hydrocracking at a relatively low reaction temperature. Because the light components of the distillate oil can quickly exit the system after hydrogenation, the forward reaction rate can be increased, allowing the hydrogenation reaction to achieve a higher reaction rate even at a relatively low reaction temperature. Simultaneously, the heat generated by the hydrogenation reaction can also escape from the reaction bed along with the light components, preventing the bed from overheating. The lower reaction temperature, coupled with the rapid exit of products and heat from the reaction system, reduces the condensation reaction of condensed aromatic hydrocarbons and reduces the risk of catalyst clogging.

[0025] 3) The design and layout of the hollow baffles in the hydrogen distribution space of the present invention can allow the hydrogen feed in one area to enter the adjacent area when the catalyst bed in that area is clogged, which is more conducive to improving the efficiency of the cracking reaction.

[0026] 4) The structural design of the distribution plate and distribution cone of the liquid redistribution assembly of the present invention is more conducive to the passage of gaseous products and the interception of liquid products and their uniform reflux to the reaction chamber.

[0027] 5) Compared with traditional pre-distillation treatment, the heavy oil part is further converted to lighter oil through hydrocracking, thereby improving the resource utilization of coal tar, and the process flow is simple and the operating cost is low.

[0028] 6) The present invention utilizes a distillation separation chamber to promptly recover light intermediate products through flash evaporation and stripping, effectively controlling their reaction rate. Furthermore, since the product partial pressure remains low, the reaction rate is accelerated, which not only improves reaction efficiency but also removes undesirable components such as hydrogen sulfide and ammonia that are prone to coking.

[0029] 7) The preferred catalyst of the present invention is supported on a porous material, which increases the porosity and the flux of the catalyst bed without causing flooding.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the internal structure of the hydrodistillation reactor of the present invention.

[0032] Figure 2 It is a side view of the first embodiment of the hollow partition of the hydrogen distribution space of the hydrodistillation reactor of the present invention (applicable to the horizontal tank structure; the partition extends to the catalyst bed).

[0033] Figure 3 It is a side view of a second embodiment of the hollow partition of the hydrogen distribution space of the hydrodistillation reactor of the present invention (applicable to a horizontal tank structure; the partition is located below the catalyst bed).

[0034] Figure 4 It is a top view of the third embodiment of the hollow partition of the hydrogen distribution space of the hydrodistillation reactor of the present invention (applicable to the flat cylindrical tank structure; the partition extends to the catalyst bed).

[0035] Figure 5 It is a side view of a third embodiment of the hollow partition of the hydrogen distribution space of the hydrodistillation reactor of the present invention (applicable to a flat cylindrical tank structure; the partition extends to the catalyst bed).

[0036] Figure 6 It is a top view of the first embodiment of the liquid redistributor in the hydrodistillation reactor of the present invention (applicable to the flat cylindrical tank structure).

[0037] Figure 7 It is a top view of the second embodiment of the liquid redistributor in the hydrodistillation reactor of the present invention (applicable to the horizontal tank structure).

[0038] Figure 8It is a side view of a second embodiment of the liquid redistributor in the hydrodistillation reactor of the present invention (applicable to a horizontal tank structure).

[0039] Figure 9 It is a structural schematic diagram of the through hole of the liquid redistributor of the present invention.

[0040] Figure 10 It is a process flow diagram of the low-temperature coal tar hydrotreating system of the present invention.

[0041] Description of main reference numerals:

[0042] 1-hydrogenation distillation reactor; 2-hydrogenation refining reactor; 3-high-pressure separator; 4-low-pressure separator; 5-fractionation tower; 6-first hydrogen purification system; 7-second hydrogen purification system; 8-heavy oil pump;

[0043] L1 - coal tar feed; L2 - gaseous products; L3 - hydrotreating products; L4 - high-pressure separated liquid products; L5 - low-pressure separated liquid products; L6 - naphtha products; L7 - diesel products; L8 - tail oil; L9, L10 - heavy oil; H1 - new hydrogen; H2, H3 - recycled hydrogen;

[0044] 101-reaction chamber; 102-catalyst bed; 103-heavy oil tank; 104A / B-liquid redistribution assembly; 1041A / B-distribution cone; 1042-through hole; 105-distillation separation chamber; 106-mixing section; 107-separation section; 108-stabilization section; 109A / B / C-hollow partition; 1091-hollow hole. DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0046] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0047] In this document, for ease of description, spatially relative terms such as "below," "beneath," "down," "above," "above," etc. may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that the spatially relative terms are intended to encompass different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Therefore, the exemplary term "below" can include both below and above directions. Objects may also have other orientations (rotated 90 degrees or other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0048] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0049] like Figure 1 As shown, the present invention provides a medium-low temperature coal tar hydrodistillation reactor, which includes: a reaction chamber 101, a distillation separation chamber 105 and a heavy oil bin 103. Among them, a transversely penetrating catalyst bed 102 is provided in the reaction chamber 101, and the equivalent diameter-to-height ratio of the catalyst bed is preferably 3:1 to 6:1 (the equivalent diameter formula is de=4A / L, A is the cross-sectional area of ​​the bed, and L is the circumference of the bed); the medium-low temperature coal tar after dehydration and impurity removal is in reverse contact with the preheated hydrogen feed in the catalyst bed 102 to carry out a hydrocracking reaction. The operating conditions of the hydrocracking reaction process are preferably as follows: the reaction temperature is 300℃~400℃, the reaction pressure is 10MPa~20MPa, the hydrogen-to-oil volume ratio is 200:1~800:1, and the volume space velocity is 0.2h -1 ~2.0h -1. The reaction chamber 101 used in the present invention is a horizontal tank structure or a flat cylindrical tank structure, so that the equivalent diameter-to-height ratio of the catalyst bed is relatively large. Experiments have shown that the use of an equivalent diameter-to-height ratio of 3:1 to 6:1 can greatly increase the material flux through the bed, while reducing the residence time of the material and heat in the catalyst bed. At the same time, the generated gaseous products can be quickly taken out of the reactor, and the blockage phenomenon caused by the long retention time of by-products in the bed in traditional reactors will not occur. The distillation separation chamber 105 is arranged at the upper part of the reaction chamber 101 and is connected to the reaction chamber. The gaseous products after the hydrocracking reaction enter the distillation separation chamber 105 under the action of countercurrent hydrogen, and the gaseous products can be distilled and separated in the distillation separation chamber. Preferably, but not restrictively, the distillation separation chamber 105 may include a mixing section 106, a separation section 107 and a stabilization section 108 from bottom to top. The heavy oil tank 103 is arranged at the bottom of the reaction chamber 101, for receiving the liquid products generated by the hydrocracking reaction and partially using them as reflux feed.

[0050] Further Figure 1 As shown, Figure 1 The reaction chamber shown is a horizontal tank structure, which is arranged axially in the horizontal direction and has ends provided with caps. The present invention can also adopt a flat cylindrical tank structure, which is arranged axially in the longitudinal direction, and both can achieve basically the same technical effect.

[0051] Further Figure 1 As shown, the catalyst bed 102 of the present invention is loaded with a hydrocracking catalyst. The catalyst shape can be any conventional hydrocracking catalyst, preferably a porous catalyst, a shaped catalyst, and / or a honeycomb catalyst. The porous catalyst has a pore diameter of 1 to 50 mm, preferably 4 to 20 mm; the shaped catalyst has an average particle diameter of 2 to 50 mm, preferably 4 to 30 mm; the honeycomb catalyst has a pore diameter or pore side length of 1 to 50 mm, preferably 3 to 15 mm. The catalyst support can be a ceramic honeycomb, Pall rings, Raschig rings, rectangular saddle rings, saddle-shaped, open-hole ring-type, half-ring, stepped ring, double arc, Haier ring, conjugated ring, flat ring, rosette, hollow sphere, or other porous support. The catalyst contains Y-type zeolite, alumina, and at least one metal component selected from Group VIII and at least one metal component selected from Group VIB. In both catalysts, the Group VIB metal is selected from molybdenum and / or tungsten, and the Group VIII metal is selected from cobalt and / or nickel. The metal composition is calculated by weight as follows: 10% to 30% tungsten oxide, 5% to 15% nickel oxide, and may contain a certain amount of molecular sieves, such as one or both of Y-type molecular sieve and β-type molecular sieve, generally 1% to 30% of molecular sieve, and the rest is a refractory tungsten oxide carrier such as amorphous silicon aluminum, silicon-containing aluminum oxide, aluminum oxide, etc. The catalyst pore volume is 0.10 to 0.50 ml / g, and the specific surface area is 120 to 350 m 2 / g.

[0052] Further Figure 1 As shown, a coal tar distribution assembly is provided above the catalyst bed 102. Coal tar feed L1 passes through this distribution assembly, evenly distributing the medium- and low-temperature coal tar across the catalyst bed 102. The coal tar distribution assembly can employ a showerhead distributor, coil distributor, porous straight tube distributor, straight tube baffle distributor, baffle distributor, tangential circulation distributor, rotating vane distributor, or double-row vane distributor. The present invention prefers porous tube distributors and straight tube baffle distributors. The pore diameter of the tube distributor is 0.5 to 20 mm, preferably 2 to 10 mm. The farther from the feed oil inlet, the larger the pore diameter. The height of the distributor from the reactor bed top is 50 to 500 mm. The choice of height is dependent on the properties, temperature, and pressure of the feed oil. At higher temperatures, the distributor height from the bed is increased, allowing for a more even distribution of the distribution within a higher space. Similarly, higher pressure allows for a larger distributor spray angle, allowing for a lower height from the reactor bed top, saving space. The catalyst bed porosity can range from 15% to 85%, preferably from 20% to 75%. By selecting the right porosity and using a porous catalyst support, the catalyst bed flux can be increased without flooding.

[0053] Further Figure 1 As shown, a hydrogen distribution space is provided at the bottom of the catalyst bed 102. When the reaction chamber adopts a horizontal tank structure as shown in the figure, a plurality of hollow partitions 109 are arranged in parallel in the vertical direction in the hydrogen distribution space, and hydrogen inlets are provided in the areas separated by the partitions. The hollow partitions 109 can extend upward into the catalyst bed 102 (i.e., as shown in the figure), or can be arranged below the catalyst bed 102. Preferably, but not restrictively, the porosity of the partition below the catalyst bed is less than 70%, and the porosity of the partition within the catalyst bed is greater than 50%. By adopting the design of the partition, multiple hydrogen inlets can be used and relatively independent areas can be separated, so that the rising hydrogen entering the catalyst bed is more uniform and the cracking reaction is more sufficient; the partition is designed to be hollow, so that when the catalyst bed in one area is blocked, the hydrogen feed in this area can enter the adjacent area, which is more conducive to improving the efficiency of the cracking reaction.

[0054] Further Figure 2-5 As shown, when the reactor adopts a horizontal tank structure, the hollow partition 109 can adopt a circular partition (refer to Figure 2 、 3 Schematic diagram of the side structure), that is, when the hollow partition 109 extends into the catalyst bed 102, the Figure 2 When the hollow partition 109 is only provided at the bottom of the catalyst bed 102 (ie Figure 1 When the hydrogen distribution space in Figure 3 The diameter of the hollow hole 1091 is preferably 8 to 20 mm. Further, when the reactor adopts an oblate cylindrical tank structure, the hollow partition 109 can be set to Figure 4 and Figure 5 The coaxial ring structure shown (wherein Figure 4 A top-down diagram is shown. Figure 5 is a side view schematic diagram).

[0055] Further Figure 1 As shown, the cross-sectional area ratio of distillation separation chamber 105 to reaction chamber 101 is preferably 1:1.2 to 1:10. As previously described, distillation separation chamber 105 includes a mixing section 106, a separation section 107, and a stabilization section 108. Of the gaseous products after the hydrocracking reaction in the reaction chamber, the lightest component (containing hydrogen) flows out of the top of distillation separation chamber 105, undergoes hydrogen purification, and is used as recycled hydrogen. Other light components flow out of the separation section 107 through a side stream for subsequent hydrorefining.

[0056] Further Figure 1 As shown, a liquid redistribution component 104 is provided at the connection between the reaction chamber 101 and the distillation separation chamber 105. The liquid redistribution component can effectively intercept the droplets while allowing the gas phase product to pass through, so that the droplets return to the reaction chamber 101. If the reactor adopts a flat cylindrical tank structure, then the Figure 6 The structure of the liquid redistribution assembly 104A shown in FIG. 1 is shown in FIG. 1 ; if the reactor adopts a horizontal tank structure, then Figure 7 and Figure 8 The structure of the liquid redistribution assembly 104B shown in FIG. The liquid redistribution assembly 104A / B includes: a distribution plate and a distribution cone. The distribution plate is arranged above the coal tar distribution assembly (refer to FIG. Figure 1 ), the distribution plate has the same shape as the top surface of the catalyst bed, and a plurality of through holes 1042 are evenly provided on the distribution plate, and an overflow ring is provided around the through hole 1042 (the structure of the through hole and the overflow ring is as shown in FIG. Figure 9 The outer edge of the distribution plate is provided with an overflow portion (which can guide the droplets back to the reaction chamber, not shown in the figure). The distribution cone 1041A / B is set at the upper center of the distribution plate, and the distribution cone is also provided with multiple through holes, and there are also Figure 9 The overflow ring shown. Preferably but not limiting, further as Figure 9 As shown, a serration portion may be provided on the inner side of the overflow ring, the serration portion is bent downward, and a guide groove is provided on the serration portion.

[0057] Furthermore, in order to better meet the passability of gas-phase products and effective interception of droplets, the porosity of the distribution plate can be 5% to 90%, the diameter of the through hole can be 5mm to 100mm, and the height of the overflow ring can be 1mm to 30mm; the top angle of the distribution cone is preferably greater than 90°, the porosity of the distribution cone is 5% to 80%, the bottom area of ​​the distribution cone is preferably 2% to 15% of the area of ​​the distribution plate, and the area of ​​the distribution plate is preferably 50% to 100% of the top surface area of ​​the catalyst bed.

[0058] like Figure 10 As shown, the present invention also provides an application Figure 1 The hydroprocessing system of the hydrodistillation reactor 1 is shown. Dehydrated and impurity-free medium-low-temperature coal tar enters the reaction chamber 101 of the hydrodistillation reactor 1 directly. The coal tar distribution assembly evenly sprays the dehydrated coal tar onto the catalyst bed 102 of the hydrodistillation reactor. The bed is divided into sections 102-1 through 102-6 by hollow partitions 109. Simultaneously, heated hydrogen H1 is introduced into the hydrodistillation reactor 101. Driven by the hollow partitions 109 and the hydrogen distribution space within the reaction chamber 101, the dehydrated coal tar moves evenly upward from the bottom of each reaction zone, where it countercurrently contacts the feedstock oil sprayed from the top within the first stage of the hydrodistillation reactor catalyst bed 102. Under an operating pressure of 6 to 20 MPa, the feedstock oil and hydrogen undergo a moderate cracking reaction under the hydrocracking catalyst in the catalyst bed. This breaks down some of the long-chain coal tar molecules into short-chain molecules, and some polycyclic aromatic hydrocarbons also undergo ring scission. The smaller hydrocarbon molecules, along with the hydrogen, then flow upward into the distillation separation chamber 105.

[0059] After separation in the distillation separation chamber 105, the lightest component flows out from the top of the distillation separation chamber 105, and is purified by the first hydrogen purification system 6 to recover the hydrogen for use as circulating hydrogen. Other light components L2 flow out from the side line and enter the hydrotreating reactor 2 (to obtain L3), the high-pressure separator 3 (to obtain L4), the low-pressure separator 4 (to obtain L5), and the product fractionation tower 5 in sequence, and are fractionated to obtain clean fuel oil products, namely naphtha product L6 and diesel product L7. The tail oil L8 returns to the hydrodistillation reactor reaction chamber 101. Preferably, but not restrictively, the reaction temperature of the hydrotreating reactor 2 is 320°C to 450°C, the reaction pressure is 8MPa to 20MPa, the hydrogen-oil volume ratio is 600:1 to 1200:1, and the volume space velocity is 0.2h -1 ~3.0h -1 .

[0060] The hydrogenated heavy components generated in the reaction chamber 101 of the hydrodistillation reactor flow downward into the heavy oil tank 103 of the hydrodistillation reactor. The liquid reflux portion L9 of the heavy oil tank 103 is returned to the reaction chamber 101 of the hydrodistillation reactor as a raw material via the circulating oil pump 8. Some of the liquid products L10 that are too bad are discharged from the system to improve the properties of the reflux material.

[0061] Example 1

[0062] Using the present invention Figure 10 The flow chart shown uses medium-low-temperature coal tar as the feedstock, with properties shown in Table 1. After being heated to 320°C, the feedstock and hydrogen enter the hydrodistillation reactor (using an oblate cylindrical tank structure). The catalyst bed within the reactor chamber has a circular cross-section, an equivalent diameter-to-height ratio of 4:1, and a bed height of 800 mm. The catalyst bed has a porosity of 50%. Four annular baffles are installed within the catalyst bed. These baffles have multiple perforations and extend upward into the catalyst bed. The baffles below the catalyst bed have an open porosity of 40%, while those within the catalyst bed have an open porosity of 70%. The hydroprocessing reactor is loaded with FC-32 hydrocracking catalyst, produced by the Catalyst Branch of Sinopec. The catalyst bed has an equivalent diameter-to-height ratio of 4:1 and a bed height of 800 mm. The feedstock for the hydrodistillation reactor is dispersed through a liquid redistribution assembly. The lighter components of the gaseous product, driven upward by hydrogen, enter the distillation separation chamber for separation. From bottom to top, the distillation separation chamber consists of a mixing section, a separation section, and a stabilization section. The mixing section is 35% of the total separator height, the separation section is 55%, and the stabilization section is 10% of the total distillation separation chamber height. The separated heavier fractions flow downward, along with the heavy components dispersed by the liquid redistribution assembly at the feed inlet, to undergo a cracking reaction under the action of the catalyst. The resulting light components rapidly exit the reaction system and enter the mixing section of the distillation separation chamber. The separated light components then flow upward into the separation section. The ratio of the distillation separation chamber diameter to the hydrogenation reactor diameter is 1:5. The insufficiently cracked heavy components flow from the bottom of the heavy oil tank through a circulation pump and are partially fed into the hydrodistillation reactor inlet as circulating oil. Some of the liquid products that are too poorly treated are discharged to improve the properties of the reflux material. The material extracted from the side line of the upper part of the reactor is used as the feedstock for the hydrotreating reactor. The hydrotreating product enters the fractionation tower after high and low fractionation to obtain clean fuel oil, namely naphtha and diesel. The reaction temperature of the hydrodistillation reactor is 340℃, the operating pressure is 10MPa, the hydrogen-oil ratio is 800:1, and the volume space velocity is 1.0h -1 The reaction temperature of the hydrotreating reactor is 370°C, the operating pressure is 14 MPa, the hydrogen-oil ratio is 800:1, and the volume space velocity is 1.0 h -1 , product distribution and product properties are shown in Table 2.

[0063] The liquid redistribution assembly consists of a gas-liquid distribution plate and a distribution cone. The distribution plate has the same top surface shape as the catalyst bed, and its area is 70% of the catalyst bed's cross-section. The distribution plate has a 50% porosity, a 10mm diameter through-hole, and a 10mm height overflow ring. The distribution cone has a 120° top angle, a 50% porosity, and a base area that is 10% of the distribution plate's area.

[0064] Example 2

[0065] The difference between this embodiment and Example 1 is that the catalyst bed in the hydrodistillation reactor has an equivalent diameter-to-height ratio of 5:1 and a bed height of 1000 mm. The number of partitions in the catalyst bed is 6. A plurality of holes are distributed on the partition; the partition extends upward to the catalyst layer, the partition below the catalyst layer has an opening rate of 30%, and the partition within the catalyst layer has an opening rate of 80%. The distribution plate area of ​​the liquid redistribution assembly is 90% of the cross-section of the catalyst bed. The opening rate of the distribution plate is 80%, the diameter of the through hole is 20 mm, and the height of the overflow ring is 20 mm. The top angle of the distribution cone is 150°, the opening rate is 70%, and the bottom area of ​​the distribution cone is 15% of the distribution plate area. The remaining conditions are the same as in Example 1.

[0066] Example 3

[0067] The same as Example 1, except that the porosity of the catalyst bed in the hydrodistillation reactor is 30% and the catalyst bed height is 500 mm.

[0068] Example 4

[0069] The same as Example 1, except that the ratio of the diameter of the distillation separation chamber to the diameter of the reaction chamber of the hydrodistillation reactor is 1:8.

[0070] Example 5

[0071] The same as Example 1, except that the ratio of the diameter to the height of the catalyst bed cross-sectional area in the hydrodistillation reactor is 6:1.

[0072] Comparative Example 1

[0073] A conventional pre-distillation-hydrogenation refining process was employed. Conventional equipment was used for both the pre-distillation and hydrofining reactors. The feedstock was cut in the pre-distillation column to obtain a light fraction, which then entered the hydrofining reactor along with hydrogen, with the reaction proceeding from top to bottom. In the comparative example, the separation temperature with the distillation column was 370°C. The catalyst loaded in the refining reactor was the same as in Example 1, at a 1:1 volume ratio. A full tail oil recycle process was employed, with the tail oil being periodically discarded. All other process conditions were the same as in Example 1.

[0074] Table 1 Properties of crude oil

[0075] project data Family composition, % data <![CDATA[Density, g / cm 3 > 1.0881 Saturation 17.1 <![CDATA[Viscosity / mm 2 / s]]> 26.8 Aroma 22.17 Sulfur content, vol% 0.56 colloid 42.01 Nitrogen content, % 0.98 Asphaltene 11.72 Carbon residue value, % 14.05 Total metal content, μg / g 215.44

[0076] Table 2 Product distribution and product properties of Examples and Comparative Examples

[0077]

[0078] Compared with traditional pre-fractionation-fixed-bed hydrorefining technology, this invention improves total liquid yield. The heavy oil discharged from traditional pre-fractionation is partially converted into light components through hydrodistillation. The timely removal of light components from the catalyst bed promotes the forward reaction, allowing the reaction rate to be increased at lower temperatures. This slows down the condensation reaction caused by high temperatures, reduces coking and clogging of the catalyst bed, and extends the operating cycle of the device. Furthermore, the temperature distribution of the reaction bed is uniform.

[0079] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is apparent that many changes and variations are possible in light of the foregoing teachings. The exemplary embodiments are selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. Any simple modifications, equivalent variations, and modifications made to the exemplary embodiments described above are intended to fall within the scope of protection of the present invention.

Claims

1. A hydroprocessing system, characterized in that: A medium-low temperature coal tar hydrodistillation reactor is used; the medium-low temperature coal tar hydrodistillation reactor comprises: The reaction chamber is provided with a transversely penetrating catalyst bed having an equivalent diameter-to-height ratio of 3:1 to 6:

1. The dehydrated and impurity-removed medium- and low-temperature coal tar and the preheated hydrogen feed are in reverse contact in the catalyst bed to carry out a hydrocracking reaction. A distillation separation chamber is provided at the upper portion of the reaction chamber and is in communication with the reaction chamber. Gas products after the hydrocracking reaction enter the distillation separation chamber under the action of countercurrent hydrogen, and the gas products are distilled and separated in the distillation separation chamber. A heavy oil tank is provided at the bottom of the reaction chamber and is used to receive the liquid product generated by the hydrocracking reaction and partially used as reflux feed; The lightest component separated by the distillation separation chamber flows out from the top of the hydrodistillation reactor, and is purified by the hydrogen purification system and then recovered for use as circulating hydrogen; the remaining light components flow out from the side line and enter the hydrorefining reactor, high-pressure separator, low-pressure separator and product fractionation tower in sequence, and are fractionated to obtain naphtha fraction, diesel fraction and tail oil, and the tail oil is returned to the reaction chamber of the hydrodistillation reactor.

2. The hydroprocessing system according to claim 1, characterized in that The reaction chamber is a horizontal tank structure or an oblate cylindrical tank structure; the horizontal tank is arranged axially in the transverse direction and has heads at both ends; the oblate cylindrical tank is arranged axially in the longitudinal direction.

3. The hydroprocessing system according to claim 2, characterized in that A hydrogen distribution space is provided under the catalyst bed. When the reaction chamber is a horizontal tank structure, a plurality of hollow partitions are provided in parallel along the vertical direction in the hydrogen distribution space, and hydrogen inlets are provided in the areas separated by the partitions.

4. The hydroprocessing system according to claim 3, characterized in that The hollow partition extends upward to the catalyst bed layer, the partition opening rate below the catalyst bed layer is less than 70%, and the partition opening rate within the catalyst bed layer is greater than 50%.

5. The hydroprocessing system according to claim 2, characterized in that A hydrogen distribution space is provided under the catalyst bed. When the reaction chamber is a flat cylindrical tank structure, a plurality of coaxial annular partitions are provided in the hydrogen distribution space.

6. The hydroprocessing system according to claim 2, characterized in that A coal tar distribution component is provided on the upper portion of the catalyst bed to evenly distribute the medium and low temperature coal tar on the catalyst bed.

7. The hydroprocessing system according to claim 6, characterized in that A liquid redistributor is provided at the connection between the reaction chamber and the distillation separation chamber, and the liquid redistributor comprises: a distribution plate disposed above the coal tar distribution assembly, the distribution plate having the same shape as the top surface of the catalyst bed, a plurality of first through holes uniformly formed on the distribution plate, a first overflow ring being provided around the first through holes, and an overflow portion being provided on the outer edge of the distribution plate; A distribution cone is arranged at the upper center of the distribution plate. The distribution cone is provided with a plurality of second through holes. A second overflow ring is provided around the second through holes.

8. The hydroprocessing system according to claim 7, characterized in that The porosity of the distribution plate is 5% to 90%, the diameter of the first through hole is 5 mm to 100 mm, and the height of the first overflow ring is 1 mm to 30 mm; the top angle of the distribution cone is greater than 90°, the porosity of the distribution cone is 5% to 80%, and the height of the second overflow ring is 1 mm to 30 mm; the bottom area of ​​the distribution cone is 2% to 15% of the area of ​​the distribution plate, and the area of ​​the distribution plate is 50% to 100% of the top surface area of ​​the catalyst bed.

9. The hydroprocessing system according to claim 7, characterized in that: A serration portion is provided on the inner side of the first overflow ring. The serration portion is bent downward and a guide groove is provided on the serration portion.

10. The hydroprocessing system according to claim 2, characterized in that: The catalyst bed layer adopts a porous catalyst; the catalyst carrier is a porous carrier.

11. The hydroprocessing system according to claim 2, wherein: The ratio of the cross-sectional area of ​​the distillation separation chamber to that of the reaction chamber is 1:1.2 to 1:

10.

12. The hydroprocessing system according to claim 2, wherein: The distillation separation chamber includes a mixing section, a separation section and a stabilization section from bottom to top; the lightest component in the gaseous product from the reaction chamber flows out from the top of the distillation separation chamber and is used as circulating hydrogen; other light components flow out from the side line in the separation section for hydrogenation refining.

13. The hydroprocessing system according to claim 2, wherein: The operating conditions of the coal tar hydrocracking reaction process in the hydrodistillation reactor are as follows: reaction temperature of 300°C to 400°C, reaction pressure of 10MPa to 20MPa, hydrogen to oil volume ratio of 200:1 to 800:1, volume space velocity of 0.2h -1 ~2.0h -1 .

14. The hydroprocessing system according to claim 1, wherein The reaction temperature of the hydrotreating reactor is 320℃~450℃, the reaction pressure is 8MPa~20MPa, the hydrogen-oil volume ratio is 600:1~1200:1, and the volume space velocity is 0.2h -1 ~3.0h -1 .

Images