A Fischer-Tropsch synthetic oil hydrocatalytic distillation device and method

Abstract

The present invention discloses a Fischer-Tropsch synthetic oil hydrogenation catalytic distillation device and method thereof. The device comprises: a hydrogenation refining reactor and a catalytic reaction distillation tower, the catalytic reaction distillation tower comprises at least one catalytic reaction zone, the catalytic reaction zone is a 2-n-layer tower plate structure, each tower plate is filled with a catalyst bed; an inclined partition is arranged on the top of each catalyst bed; a gas phase channel is arranged through each catalyst bed and the inclined partition. By adopting the device of the present invention, the gas phase product produced by the hydrocracking reaction can leave the cracking reaction zone in time and will not enter the upper catalyst bed again, so as to avoid the gas phase product occupying the cracking catalyst pores, effectively prevent the secondary cracking and gasification of the target product, and improve the selectivity of the reaction and the yield of the target product.

Description

Technical Field

[0001] The invention belongs to the field of hydrogenation reaction, and in particular, relates to a hydrogenation catalytic distillation device and method for Fischer-Tropsch synthetic oil. Background Art

[0002] With the rapid development of the transportation industry, natural oil resources are increasingly in short supply, and countries around the world are actively exploring and developing alternative products for oil resources. The general characteristics of my country's energy structure are "rich in coal, lacking in oil, and little gas". Using coal as raw material to produce synthesis gas and using synthesis gas to produce liquid hydrocarbons through Fischer-Tropsch synthesis is one of the important ways to solve the current shortage of fuel.

[0003] The Fischer-Tropsch synthesis reaction is a process in which hydrogen and carbon monoxide are used as raw materials, and the Fischer-Tropsch synthesis reaction occurs under the action of a catalyst to produce liquid fuel. The raw materials are mainly coal and natural gas. Fischer-Tropsch synthetic oil is mainly composed of normal alkanes, olefins and a certain amount of oxygen-containing compounds. Its non-ideal components such as sulfur, nitrogen, and aromatics are extremely low in content, and it is greatly different from conventional mineral petroleum in terms of hydrocarbon composition and main properties. The naphtha fraction in Fischer-Tropsch synthetic oil basically does not contain sulfur and nitrogen, has a very low octane number (most of the olefins and alkanes are straight chains), and has the highest olefin content and oxygen content; the diesel fraction has extremely low sulfur, nitrogen and aromatic content, a very high cetane number, a medium olefin content and oxygen content, and the heavy oil olefin content and oxygen content are the lowest. Therefore, Fischer-Tropsch synthetic oil must undergo corresponding hydrogenation treatment to obtain petrochemical raw materials or transportation fuels that meet the use specifications.

[0004] The general process flow of hydrotreating Fischer-Tropsch synthetic oil is that after the Fischer-Tropsch synthetic oil (including naphtha fraction, diesel fraction and heavy oil fraction) is mixed with hydrogen, it first enters the hydrotreating reactor, and then enters the fractionation system after olefin saturation and acid-containing oxygen-containing compound hydrodeoxygenation reaction on the catalyst bed. In the fractionation tower, the hydrotreating product is separated into naphtha, diesel and heavy oil by distillation. The heavy oil continues to enter the subsequent hydrocracking reactor, and the cracking product enters the second set of fractionation system. The tail oil is partially or fully recycled back to the hydrocracking reactor, with the purpose of obtaining more naphtha and diesel fractions through cracking reaction. These processes all adopt the traditional fixed bed hydrogenation mode, and completely separate the hydrotreating and hydrocracking parts, with two sets of fractionation systems, which are complicated in process, high in equipment investment and high in energy consumption.

[0005] The heavy oil hydrocracking reaction in the current Fischer-Tropsch synthetic oil still adopts the traditional fixed-bed hydrogenation mode, where the feedstock oil and hydrogen flow into the reactor together, and the materials react and flow downward during the bed advancement process. During the entire reaction process, the gas phase reaction products cannot leave the reactor in time, so they will occupy the catalyst pores and cracking reaction will occur again, resulting in a decrease in the selectivity of the reaction and the yield of the target product. In addition, since the content of normal alkanes in the heavy oil fraction of the Fischer-Tropsch synthetic oil is as high as more than 80%, the olefin products after the cracking of normal alkanes will quickly undergo olefin saturation, and the olefin saturation heat is large, resulting in the entire reaction The heat release is much greater than that of traditional petroleum-based crude oil, and the hydrogen consumption increases, the bed temperature is difficult to control, and it is very easy to produce the risk of "flying temperature". Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a Fischer-Tropsch synthetic oil hydrogenation device and method, so as to overcome the shortcomings of the prior art that the gas phase reaction products cannot be effectively separated from the reaction zone in time, improve the yield and selectivity of the target product, prevent the large amount of olefin saturation, and eliminate the risk of "overheating" of the bed.

[0007] The first aspect of the present invention is to provide a Fischer-Tropsch synthesis oil hydrocatalytic distillation device, comprising:

[0008] (1) a hydrotreating reactor, used for performing a hydrotreating reaction on the raw material Fischer-Tropsch synthetic oil;

[0009] (2) A catalytic reaction distillation tower, comprising at least one catalytic reaction zone, wherein the catalytic reaction zone is a 2-n-layer tower plate structure, each tower plate is loaded with a catalyst bed, wherein n is an integer greater than 2; an inclined partition, preferably an umbrella-shaped partition, is arranged on the top of each catalyst bed; and a gas phase channel is arranged through each catalyst bed and the inclined partition.

[0010] Furthermore, in the above technical solution, the hydrorefining reaction includes olefin saturation, hydrodeoxygenation, hydrodemetallization, etc.

[0011] Furthermore, in the above technical solution, the catalytic reaction distillation tower also includes a liquid-phase feed subunit, which is arranged above the inclined partition of the topmost catalyst bed, and the liquid-phase feed is guided to the catalyst bed through the inclined partition.

[0012] Furthermore, in the above technical solution, an annular downcomer is provided at the end of the inclined partition, and the bottom of the annular downcomer is spaced a distance from the bottom of the catalyst bed, so that the liquid feed enters the catalyst bed in a radial direction.

[0013] Furthermore, in the above technical solution, the catalytic reaction distillation tower further comprises a gas phase feed subunit, which is arranged between the catalyst bed layer of the upper layer and the inclined partition plate of the lower layer. The gas phase feed enters the catalyst bed layer of the upper layer upward.

[0014] Furthermore, in the above technical solution, the lower end of the gas phase channel passing through the upper catalyst bed is connected to the inclined partition plate on the next catalyst bed. This design makes the gas phase channel and the gas phase feed subunit relatively isolated, and the gas phase product generated after the gas phase feed and the liquid phase feed react in the catalyst bed directly enters the gas phase channel.

[0015] Furthermore, in the above technical solution, the catalyst bed is provided with: an overflow weir, which is arranged on the side close to the gas phase channel; and a liquid sealing baffle, which is arranged on the upper part of the overflow weir to isolate the gas phase feed from the gas phase product.

[0016] Furthermore, in the above technical solution, the liquid seal baffle includes: a horizontal portion, which is an annular flat plate and is located above the overflow weir; a vertical portion, which is cylindrical and is integrally formed with the horizontal portion, and the lower end of the vertical portion is spaced a distance from the bottom of the catalyst bed.

[0017] Furthermore, in the above technical solution, the liquid-phase feed subunit further includes: a liquid-phase feed pipe, which extends along the radial direction of the catalyst bed; a liquid-phase distribution pipe, which is annular and intersects orthogonally or tangentially with the liquid-phase feed pipe, and the tube wall of the liquid-phase distribution pipe is provided with a plurality of channels for evenly distributing the liquid-phase feed to all directions of the annular downcomer.

[0018] Furthermore, in the above technical solution, the gas-phase feed subunit further includes: a gas-phase feed pipe, which extends along the radial direction of the catalyst bed; a gas-phase distribution pipe, which is in a ring shape or a multi-layer concentric ring shape, and the gas-phase distribution pipe intersects the gas-phase feed pipe orthogonally or tangentially, and a plurality of holes are provided on the wall surface of the gas-phase distribution pipe for evenly distributing the gas-phase feed to all directions at the bottom of the catalyst bed.

[0019] Furthermore, in the above technical solution, the gas phase feeding subunit may also include: a gas phase distribution plate, which is located at the bottom of the catalyst bed and is disk-shaped as a whole, and a plurality of holes are evenly and densely distributed on the gas phase distribution plate.

[0020] Furthermore, in the above technical solution, the gas phase channel is located in the middle of the catalytic reaction unit and passes through all catalyst beds from bottom to top.

[0021] In the above technical solution, the uppermost end of the gas phase channel exits the hydrogenation reactor, and the lowermost end is close to the bottom of the hydrogenation reactor. The port needs to be immersed in the liquid phase product, and a liquid level monitoring unit is provided at the bottom of the hydrogenation reactor.

[0022] Furthermore, in the above technical solution, the height of the filler or catalyst bed is set to 10 mm to 1000 mm according to different reaction systems.

[0023] Furthermore, in the above technical solution, the upper edge of the overflow weir may be 10 to 100 mm higher than the upper surface of the catalyst bed.

[0024] Furthermore, in the above technical solution, the gas phase distribution pipe can be arranged below the catalyst bed or inside the catalyst bed.

[0025] Furthermore, in the above technical solution, a separation zone is provided at the upper part of the catalytic reaction distillation tower; the ratio of the number of catalyst beds in the separation zone to that in the catalytic reaction zone is 1:1 to 1:n-1. Fillers or hydrocracking catalysts can be selectively placed on the catalyst bed in the separation zone, preferably solid fillers. The catalyst bed in the catalytic reaction zone is loaded with a hydrocracking catalyst.

[0026] Furthermore, in the above technical solution, a fractionation tower can be selectively arranged between the hydrotreating reactor and the catalytic reaction distillation tower.

[0027] The second aspect of the present invention is to provide a Fischer-Tropsch oil hydrogenation method, comprising the following steps:

[0028] (1) The Fischer-Tropsch synthetic oil is mixed with hydrogen and then enters a hydrotreating reactor to undergo a hydrotreating reaction under the action of a hydrotreating catalyst;

[0029] (2) The logistics obtained by the hydrotreating in step (1) enters a catalytic reaction distillation tower, descends in the tower and sequentially enters a plurality of catalyst beds, and contacts and reacts with the hydrogen entering the catalyst beds upward; the gaseous product obtained by the reaction of each catalyst bed enters a gas phase channel, and flows upward out of the catalytic reaction distillation tower in the gas phase channel; the liquid product obtained by the reaction of each catalyst bed sequentially enters the next catalyst bed to react, and the final liquid product flows downward out of the catalytic reaction distillation tower.

[0030] Furthermore, in the above technical scheme, the gaseous product flowing out of the top of the catalytic reaction distillation tower is mixed with the liquid product flowing out of the bottom of the tower, and then separated and fractionated to obtain high-pressure hydrogen-rich gas, naphtha, diesel and heavy oil, and all or part of the heavy oil is returned to the catalytic reaction distillation tower for hydrocracking reaction.

[0031] Furthermore, in the above technical solution, the obtained high-pressure hydrogen-rich gas is recycled.

[0032] Furthermore, in the above technical solution, the hydroprocessing refined logistics enters the catalytic reaction distillation tower, and first enters the separation zone when descending in the tower, and is separated into light components and heavy components. The heavy components move downward into the catalyst bed to react, and the light components are directly mixed with the gas phase products and flow out of the catalytic reaction distillation tower from the top.

[0033] Furthermore, in the above technical solution, the light components in step (2) generally refer to C1-C4 gas, naphtha and kerosene fractions, and the heavy components generally refer to diesel and wax oil fractions.

[0034] Furthermore, in the above technical solution, the Fischer-Tropsch synthesis oil includes high-temperature Fischer-Tropsch synthesis full-fraction oil and low-temperature Fischer-Tropsch synthesis full-fraction oil, preferably low-temperature Fischer-Tropsch synthesis full-fraction oil. The properties of the Fischer-Tropsch synthesis oil are as follows: density 0.6 g / cm 3 ~1.0g / cm 3 , preferably 0.7g / cm3~0.95g / cm 3 ; Final distillation point 650℃~750℃, preferably 680℃~720℃.

[0035] Furthermore, in the above technical scheme, the hydrogenation reactor described in step (1) is a conventional fixed bed hydrogenation reactor, which contains a hydrorefining catalyst bed. The hydrorefining catalyst bed preferably has a hydrogenation protective agent placed on the upper part and a hydrorefining catalyst placed on the lower part, and the volume ratio of the hydrogenation protective agent to the hydrorefining catalyst is 0 to 3:10, preferably 1:20 to 1:5. The hydrogenation protective agent and the hydrorefining catalyst are both conventional protective agents and refining catalysts. Generally, alumina or silicon-containing alumina is used as a carrier, and metals of Group VIB and Group VIII are used as active components, such as one, two or more selected from W, Mo, Co, and Ni, and the hydrogenation protective agent has a larger pore size than the hydrorefining catalyst.

[0036] Further, in the above technical scheme, the operating conditions of the Fischer-Tropsch synthetic oil hydrorefining process described in step (1) are as follows: reaction temperature is 200°C to 400°C, reaction pressure is 3MPa to 18MPa, hydrogen-to-oil volume ratio is 100 to 1000, liquid hourly volume space velocity is 0.5h -1 ~10.0h -1 The preferred operating conditions are: reaction temperature of 250°C to 390°C, reaction pressure of 4MPa to 15MPa, hydrogen to oil volume ratio of 200 to 1000, liquid hourly volume space velocity of 0.5h -1 ~8.0h -1 .

[0037] Furthermore, in the above technical solution, the number of catalyst beds described in step (2) is n layers, the upper layer can be selectively placed with fillers or hydrocracking catalysts, preferably solid fillers, and the lower layer is filled with hydrocracking catalysts, and the layer ratio of solid fillers to hydrocracking catalysts is preferably 1:1 to 1:n-1. The fillers are conventional in the art, such as the fillers can be selected from one or more random packings such as ball rings, Raschig rings, rectangular saddle rings, saddles, open-hole rings, half rings, step rings, double arcs, Haier rings, conjugated rings, flat rings, rosettes, etc. The fillers can also be selected from metal or ceramic corrugated fillers. The hydrocracking catalyst generally includes an active component and a carrier, the carrier component includes one or more of alumina, silicon-containing alumina and molecular sieves, preferably molecular sieves, and the molecular sieves can be Y-type molecular sieves; the active component is one or more of Group VIB and Group VIII metals, Group VIB metals are generally Mo and / or W, and Group VIII metals are generally Co and / or Ni. The shape of the hydrocracking catalyst can be any conventional existing hydrocracking catalyst shape, 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 average particle diameter of the shaped catalyst is 2 to 50 mm, preferably 4 to 30 mm; the pore diameter or pore side length of the honeycomb catalyst is 1 to 50 mm, preferably 3 to 15 mm; the catalyst bed void ratio is recommended to be 15% to 85%, preferably 20% to 75%.

[0038] Further, in the above technical solution, the operating conditions of the catalytic distillation reactor in step (2) are: reaction temperature of 260°C to 450°C, reaction pressure of 3MPa to 20MPa, hydrogen to oil volume ratio of 100 to 2000, liquid hourly volume space velocity of 0.1h -1 ~10.0h -1 The preferred operating conditions are: reaction temperature of 300°C to 450°C, reaction pressure of 4MPa to 15MPa, hydrogen to oil volume ratio of 100 to 1500, liquid hourly volume space velocity of 0.5h -1 ~10.0h -1 .

[0039] Furthermore, in the above technical solution, after the hydrotreating in step (1), the hydrotreating product can be selectively fractionated to obtain naphtha, diesel and heavy oil fractions, wherein the heavy oil fraction enters a catalytic reaction distillation tower for further hydrotreating.

[0040] After a lot of research, it was found that for the gas-liquid-solid three-phase reaction process in which the amount of liquid phase decreases rapidly and the amount of gas phase increases rapidly during the reaction, the rapid increase in the amount of gas phase occupies a large amount of bed space, which greatly increases the liquid phase flow rate. According to the traditional design, although the gas-liquid-solid three-phase contact can be guaranteed, the effective reaction time of the liquid phase that needs further conversion is reduced, and the probability of the gas phase that does not need to react again (such as the gas phase obtained by liquid phase conversion under reaction conditions) contacting the catalyst increases. For the system that requires more liquid phase conversion and gas phase control of secondary reaction, the overall reaction effect is subject to certain limitations, which is generally manifested as the reaction conversion rate, selectivity, etc. are difficult to further improve.

[0041] Research has found that when the overall space velocity is similar, the gas-liquid-solid three-phase hydrogenation reaction in which the liquid phase amount decreases rapidly and the gas phase amount increases rapidly during the reaction process allows the generated gas phase to quickly leave the catalyst bed, and the adverse effects of the generated gas phase have little cumulative effect. The liquid phase has a more sufficient chance to react on the catalyst, thereby overcoming the traditional understanding that a small aspect ratio will lead to adverse effects such as poor contact effects, and achieving a significant increase in the yield of the target product. At the same time, it solves the problems of easy flooding of the countercurrent reactor and limited hydrogen-to-oil ratio.

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] The gas phase products produced by the hydrocracking reaction of the present invention can leave the cracking reaction zone in time and will not enter the catalyst bed layer above again, so as to avoid the gas phase products occupying the cracking catalyst pores, effectively prevent the secondary cracking and gasification of the target product, and improve the selectivity of the reaction and the yield of the target product. At the same time, since the product partial pressure is always kept at a low state, the driving force of the reaction is increased and the equilibrium conversion rate is improved.

[0044] The heavy components of Fischer-Tropsch synthetic oil contain more than 80% normal alkanes. The gas phase products produced after the cracking of these normal alkanes are rich in olefins. These olefins can leave the distillation tower in time, effectively preventing olefin saturation and consuming hydrogen. At the same time, a large amount of heat is generated, reducing hydrogen consumption and reaction temperature rise, and preventing the risk of "temperature runaway". In addition, the gas phase products rich in olefins are high-quality chemical raw materials.

[0045] Furthermore, the light components of the hydrofining logistics of the present invention can be directly separated out of the catalytic reaction distillation tower through the gas phase channel when passing through the separation zone in the catalytic reaction distillation tower. Even if a small amount of light components are entrained into the hydrocracking reaction zone, due to the large polarity of the macromolecules in the heavy components, they can be preferentially adsorbed on the surface of the cracking catalyst to undergo a cracking reaction. The light components are affected by competitive adsorption and can be further taken away from the distillation tower through the gas phase channel with the help of the stripping effect of hydrogen. They will hardly be cracked into smaller molecules on the cracking catalyst, thereby increasing the load on the cracking reaction zone. Therefore, the present invention can achieve the separation of light and heavy components of the hydrofining logistics through the design of the catalytic reaction distillation tower without the need to specially design a distillation system after the refining reactor, thereby simplifying the reaction process.

[0046] Furthermore, the umbrella-shaped partition of the present invention can separate the gas phase feed and product gas between adjacent beds on the one hand, and play a guiding role for the liquid phase and the gas phase on the other hand. The liquid seal baffle can effectively isolate the gas phase feed from the gas phase product. The arrangement of multiple layers of concentric annular gas phase distribution pipes can keep the distribution of the gas phase feed uniform to the maximum extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The figure is a schematic diagram of a specific embodiment of the Fischer-Tropsch synthetic oil hydrocatalytic distillation process of the present invention.

[0048] Figure 2 It is a structural schematic diagram of a specific embodiment of the catalytic reaction distillation tower of the present invention.

[0049] Figure 3 It is a top view of the liquid phase distribution pipe in the catalytic reaction distillation tower of the present invention.

[0050] Figure 4 It is a top view of the gas phase feed pipe and the gas phase distribution pipe in the catalytic reaction distillation tower of the present invention (showing the situation where the gas phase feed pipe and the annular gas phase distribution pipe are orthogonally arranged).

[0051] Figure 5 It is another top view of the gas phase feed pipe and the gas phase distribution pipe in the catalytic reaction distillation tower of the present invention (showing the situation where the gas phase feed pipe and the annular gas phase distribution pipe are arranged to intersect tangentially).

[0052] Figure 6 It is a top view of the gas phase distribution pipe of the present invention which adopts a concentric double-ring distribution pipe.

[0053] Figure 7 It is a top view of the gas phase distribution plate in the catalytic reaction distillation tower of the present invention.

[0054] Figure 8 It is a top view of the catalyst support plate in the catalytic reaction distillation tower of the present invention.

[0055] Description of main reference numerals:

[0056] 1-catalytic reaction distillation tower, 2-Fischer-Tropsch synthesis oil, 3-new hydrogen, 4-high-pressure hydrogen-rich gas, 5-hydrogenation refining reactor, 6-hydrogenation refining logistics, 7-liquid phase logistics, 8-gas phase logistics, 9-high-pressure separator, 10-fractionation tower, 101-gas, 102-naphtha, 103-diesel, 104-heavy oil.

[0057] 11- umbrella-shaped partition, 110- filler, 111- solid catalyst, 12- outer downcomer, 13- gas phase channel, 14- overflow weir, 15- downcomer folding plate, 16- liquid receiving tray, 17- liquid sealing baffle, 18- inner downcomer, 19- catalyst support plate, 191- grid;

[0058] 21-liquid phase feed pipe, 22-liquid phase distribution pipe, 220-liquid phase distribution pipe body, 221-liquid phase channel;

[0059] 31 - gas phase feed pipe, 32 - gas phase distribution pipe, 320 - gas phase distribution pipe body, 321 - gas phase channel, 33 - gas phase distribution plate, 331 - eyelet. DETAILED DESCRIPTION

[0060] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0061] Figure 1 The figure shows a schematic diagram of the process flow of the Fischer-Tropsch synthesis oil hydrogenation catalytic distillation process of the present invention. Figure 1 and Figure 2 As shown, the Fischer-Tropsch synthetic oil 2 is mixed with new hydrogen 3 and circulating pressurized hydrogen-rich gas 4 and then enters the hydrotreating reactor 5, in which the hydrogenation protective agent and the hydrotreating catalyst are placed in order from top to bottom. The hydrotreating refining flow 6 enters the liquid phase feed pipe 21 of the catalytic reaction distillation tower 1, and flows downward along the packing or catalyst bed after being evenly distributed through the liquid phase distribution pipe 22. When the hydrotreating refining flow 6 passes through the packing in the separation zone, the light component flows upward through the gas phase channel 321, and the heavy component continues to flow downward. When entering the catalyst bed in the catalytic reaction zone, after reacting with the hydrogen entering the catalyst bed from the gas phase feed pipe 31 upward, the gas phase product directly enters the gas phase channel 321, and the heavy component continues to flow downward along the catalyst bed and react.

[0062] The liquid phase stream 7 generated by the hydrocracking reaction flows out from the bottom of the catalytic reaction distillation tower, and the gas phase stream 8 from the gas phase channel 321 flows out from the top of the catalytic reaction distillation tower. The two are mixed and enter the high-pressure separator 9 for gas-liquid separation. The separated high-pressure hydrogen-rich gas 4 is mixed with the new hydrogen 3 and used as circulating hydrogen. The separated liquid enters the distillation tower 10 for fractionation to obtain gas 101, naphtha 102, diesel 103 and heavy oil 104. The heavy oil 104 is fully or partially recycled to the catalytic reaction distillation tower 1 to continue the hydrocracking reaction, and can also be drawn out of the device as a raw material for producing lubricating oil base oil.

[0063] like Figure 2 As shown, the internal components of the catalytic reaction distillation tower 1 of the present invention include a catalyst bed, a liquid-phase feed subunit, a gas-phase feed subunit and a gas-phase channel. The upper part of the catalytic reaction distillation tower is set as a separation zone, and the lower part is a catalytic reaction zone. Among them, the catalyst bed in the separation zone is used to place fillers 110, and the catalyst bed in the catalytic reaction zone is used to fill solid catalysts 111. There is an inclined partition on the top of each catalyst bed. The overall shape formed by the inclined partition can be umbrella-shaped, which plays the role of a partition. On the one hand, it can separate the gas-phase feed and product gas between adjacent beds, and on the other hand, it plays a role in guiding the liquid phase and the gas phase. Preferably, but not restrictively, the umbrella surface can be arc-shaped or folding umbrella-shaped. The liquid-phase feed subunit is arranged above the inclined partition (i.e., umbrella-shaped partition 11) of the topmost catalyst bed. The liquid-phase feed is guided to the catalyst bed through the umbrella-shaped partition 11 to contact the filler 110. Specifically, an annular outer downcomer 12 is provided at the end of the umbrella-shaped partition 11. The bottom of the outer downcomer 12 is spaced a distance from the bottom of the catalyst bed, so that the liquid-phase feed enters the catalyst bed along the radial direction of the reaction distillation tower 1.

[0064] A gas-phase feed subunit is provided in each catalyst bed of the catalytic reaction zone, which is specifically provided between the catalyst bed of the upper layer and the umbrella-shaped partition 11 of the lower layer, and the gas-phase feed of each layer enters the catalyst bed upward. After the gas-liquid phase feed and the solid catalyst are fully reacted in the catalyst bed, the gas-phase product of each layer is guided to the gas-phase channel 13 along the lower part of the umbrella-shaped partition 11. The gas-phase channel 13 is in a relatively isolated state from the gas-phase feed subunit, that is, the gas-phase product generated after the gas-phase feed and the liquid-phase feed react in the catalyst bed directly enters the gas-phase channel 13. Preferably, but not restrictively, the gas-phase channel is located in the middle of the reaction distillation tower 1, and passes through all the catalyst beds from bottom to top.

[0065] like Figure 2 , 3As shown, the liquid-phase feed subunit further includes a liquid-phase feed pipe 21 and a liquid-phase distribution pipe 22. The liquid-phase feed pipe 21 extends in the radial direction of the catalytic reaction unit, and the liquid-phase distribution pipe 22 is annular. The liquid-phase feed pipe 21 intersects orthogonally or tangentially with the pipe body 220 of the liquid-phase distribution pipe 22. The pipe wall of the liquid-phase distribution pipe 22 is provided with a plurality of liquid-phase channels 221 for evenly distributing the liquid-phase feed to all directions of the annular outer downcomer 12. The openings of the liquid-phase channels 221 can be in all directions on the upper, lower and side surfaces of the pipe body. The liquid-phase feed enters the reaction distillation tower 1 through the liquid-phase feed pipe 21, is distributed into the tower through the annular liquid-phase distribution pipe 22, flows into the outer downcomer 12 toward the periphery through the umbrella-shaped partition 11, and enters the catalyst bed laterally after passing through the outer downcomer 12 to contact with the filler and the solid catalyst. The feeding direction of the liquid phase feed pipe 21 is the radial direction of the reaction distillation tower, which is orthogonal to or tangential to the radial direction of the annular liquid phase distribution pipe 22. The annular diameter of the annular liquid phase distribution pipe 22 is larger than the outer diameter of the gas phase channel 13 and smaller than the inner diameter of the reaction distillation tower 1. The multiple holes on the wall of the annular liquid phase distribution pipe 22 facilitate the uniform distribution of the liquid phase feed in all directions of the outer downcomer 12. The height of the downcomer fold 15 is generally smaller than the height of the packing or catalyst loading of this layer, and the distance between the downcomer fold 15 and the inner wall of the reaction distillation tower 1 is determined according to the flow rate of the liquid phase reactants of this layer.

[0066] Further Figure 2 As shown, the height of each catalyst bed in the reaction distillation tower 1 can be the same or different, depending on the different chemical reaction systems. The catalyst bed is fixed with a screen to keep the bed relatively stable, and the bed height is set to 10mm to 1000mm. The catalyst bed is provided with an overflow weir 14 and a liquid seal baffle 17, and the overflow weir 14 is arranged on the side close to the gas phase channel 13. The liquid seal baffle 17 is arranged on the upper part of the overflow weir 14 to isolate the gas phase feed from the gas phase product. Further, the liquid seal baffle 17 includes a horizontal part and a vertical part, the horizontal part is an annular flat plate and is located above the overflow weir 14; the vertical part is cylindrical, and the vertical part is integrally formed with the horizontal part, and other seamless connection methods can also be used. The lower end of the vertical part is spaced a distance from the bottom of the catalyst bed to ensure the outflow of the liquid phase product. The unreacted liquid feed and the reacted but liquid-phase materials in the catalyst bed pass through the overflow weir 14, through the inner downcomer 18 (i.e., the annular space between the overflow weir 14 and the outer wall of the gas phase channel 13), along the umbrella-shaped partition 11, and through the outer downcomer 12 of the next layer into the next catalyst bed. The height of the overflow weir 14 is higher than the upper plane of the catalyst in the current bed, preferably 10 to 100 mm higher. The annular inner downcomer 18 formed between the overflow weir 14 and the outer wall of the gas phase channel 13 has a spacing size determined by the size of the liquid phase load, and the size of the downcomers of each bed can be the same or different.

[0067] Further Figure 2 , 4 As shown in FIG. 6 , the gas phase feed subunit includes a gas phase feed pipe 31 and a gas phase distribution pipe 32. The gas phase feed pipe 31 extends in the radial direction of the reaction distillation tower 1. The gas phase distribution pipe 32 is annular (see FIG. Figure 4 , 5 ) or multiple layers of concentric rings (see Figure 6 The gas phase feed pipe 31 is orthogonal to the gas phase distribution pipe body 320 of the gas phase distribution pipe 32 (see Figure 4 ) or tangential intersection (see Figure 5 ), a plurality of gas phase channels 321 are provided on the wall surface of the gas phase distribution pipe 32, which are used to evenly distribute the gas phase feed to all directions at the bottom of the catalyst bed. Preferably, but not limiting, the gas phase distribution pipe 32 can be arranged below the catalyst bed, or can be arranged inside the catalyst bed. Figure 7 As shown, the gas-phase feed subunit further includes a gas-phase distribution plate 33, which is located at the bottom of the catalyst bed and is in the shape of a plate as a whole. The gas-phase distribution plate is uniformly and densely distributed with a plurality of holes 331. The gas-phase feed enters the reaction distillation tower 1 through the gas-phase feed pipes 31 of each layer, is distributed into the reaction distillation tower 1 through the annular gas-phase distribution pipe 32, and enters the catalyst bed upward through the gas-phase distribution plate 33 at the lower part of the catalyst support plate 19. The gas-phase feed pipe 31 enters the reaction distillation tower 1 in a radial direction, and intersects orthogonally or tangentially with the annular gas-phase distribution pipe 32. The annular gas-phase distribution pipe 32 is located below the catalyst bed. The annular diameter of the annular gas-phase distribution pipe 32 is smaller than the outer ring diameter of the catalyst bed, and the inner diameter is larger than the inner ring diameter of the catalyst bed. The several gas-phase channels 321 on the wall of the annular gas-phase distribution pipe 32 facilitate the uniform distribution of gas at various positions of the gas-phase distribution plate 33. The catalyst support plate 19 mainly supports the catalyst bed to ensure that the catalyst bed remains stable in the axial direction of the reaction distillation tower. The function of the gas phase distribution plate 33 is to ensure uniform distribution of the gas phase feed, while trying to avoid direct leakage of the liquid phase feed on the catalyst bed (using the gas phase distribution plate 33 of the present invention, the liquid leakage is less than 15%). When more than one concentric annular gas phase distribution pipe 32 of different diameters is arranged on the same plane, the distribution of the gas phase feed can be made more uniform. Figure 2 In the embodiment of the present invention, the annular gas phase distribution pipe 32 is arranged below the catalyst bed layer. When the annular gas phase distribution pipe 32 is installed in the catalyst bed layer, the catalyst support plate 19 can Figure 8 The grid 191 is changed into a support plate, and the gas phase distribution plate 33 is cancelled.

[0068] In the catalytic reaction unit of the present invention, liquid phase feed and gas phase feed are subjected to catalytic reaction in the catalyst bed, gas phase products and unreacted gas phase feed rise and leave the reaction system through the gas phase channel 13, and gas phase products generated after the reactants undergo chemical reaction in the catalyst bed will leave the reaction zone in time and will not enter the upper catalyst bed (isolated by the umbrella-shaped partition) again, thus avoiding secondary reaction of the target product and improving the selectivity of the reaction. At the same time, due to the departure of the product in the reaction zone, the driving force of the reaction is increased and the equilibrium conversion rate is improved.

[0069] The catalytic reaction distillation tower of the present invention can be a multi-layer plate tower structure. The number of catalyst beds in the catalytic reaction distillation tower is two or more layers. The catalytic reaction distillation tower 1 of the present invention is suitable for a reaction system in which at least one liquid feed and at least one gas feed undergo a chemical reaction on a solid catalyst, and at least one gas product is included in the reaction product. For example, hydrocracking of petroleum fractions and chemical synthetic oils, hydrodewaxing of diesel and lubricating oil fractions, and hydrotreatment processes of various petroleum fractions.

[0070] In addition to the downcomers, overflow weirs and liquid receiving trays 16, each tray of the catalytic reaction distillation tower 1 of the present invention is also provided with a liquid sealing baffle, which is connected to the gas phase channel. Adjacent trays are separated by umbrella-shaped partitions. Each tray is an annular structure, the inner edge of the annular ring is connected to the gas phase channel, and the outer edge is connected to the inner wall of the catalytic reaction distillation tower. The gas phase channel is a common channel for removing the gas phase products generated by the chemical reaction on each tray. In the embodiment of the present invention, the liquid feed positions are all on the upper part of a tray, and liquid feed can also be provided on some trays or each tray, and the gas phase feed has feed at the lower part of each tray. Above each tray is a catalyst loading area, and the liquid phase feed flows radially through the catalyst bed. The gas phase feed enters from the bottom of the tray and reacts under the action of the catalyst. The gas phase material generated after the reaction directly leaves the reaction system and enters the gas phase channel in the middle. After the liquid phase leaves the current bed, it enters the next bed through the downcomer. Since the reaction and separation are carried out simultaneously, the reaction equilibrium can be destroyed, effectively improving the conversion rate of the reactants and the selectivity of the target products.

[0071] Example 1

[0072] The raw material Fischer-Tropsch synthesis oil is subjected to catalytic distillation treatment using the above-mentioned device and process of the present invention. The properties of the raw material Fischer-Tropsch synthesis oil are shown in Table 1.

[0073] A hydrogenation protective agent is placed in the upper part of the hydrotreating reactor, and a hydrotreating catalyst is filled in the lower part, and the volume ratio of the hydrogenation protective agent to the hydrotreating catalyst is 1:10. The raw material undergoes olefin saturation, deoxygenation and impurity removal reactions in the hydrotreating reactor. The hydrogenation protective agent is FZC-105, and the hydrotreating catalyst is FHUDS-5, both of which are produced by Sinopec Dalian Petrochemical Research Institute. The specific operating process conditions are shown in Table 2.

[0074] The catalytic reaction distillation tower is provided with five trays, the upper part of the first tray is filled with filler, the lower part is filled with hydrocracking catalyst, and the remaining four trays are filled with hydrocracking catalyst. The filler is 5mm corundum Raschig ring produced by Baisheng Chemical Packing Co., Ltd., and the hydrocracking catalyst is FC-14 produced by Sinopec Dalian Petrochemical Research Institute. The specific operating process conditions are shown in Table 2.

[0075] The whole fraction of the catalytic reaction distillation tower passes through the high-pressure separator to obtain high-pressure hydrogen-rich gas 4 for reflux, and the remaining products enter the fractionation tower for fractionation to obtain gas, naphtha, diesel fraction and heavy oil fraction, of which part of the heavy oil fraction is refluxed and part is thrown out. The operating temperature of the high-pressure separator is 85°C, the operating pressure of the fractionation tower is 0.1MPa, the top temperature is 70°C, and the bottom temperature is 390°C.

[0076] Product distribution and properties are shown in Table 3.

[0077] Example 2

[0078] The same as Example 1, the only difference is that a fractionation tower is added between the hydrofining reactor and the catalytic reaction distillation tower. The hydrofining stream enters the fractionation tower for fractionation to obtain naphtha, diesel and heavy oil fractions, wherein the heavy oil fraction enters the catalytic reaction distillation tower to continue the hydrocracking reaction. The operating conditions of the added fractionation tower are 0.1MPa, the tower top temperature is 60°C, and the tower bottom temperature is 400°C.

[0079] Embodiment 3-4

[0080] The reaction conditions were changed, as shown in Table 2, and the other conditions were the same as in Example 1.

[0081] Comparative Example 1

[0082] A conventional two-stage hydrogenation process, i.e., a refining + cracking process, is adopted. Both the refining and cracking reactors adopt a reaction process in which the raw material and hydrogen flow in parallel from top to bottom. The Fischer-Tropsch synthetic oil is first subjected to olefin saturation, deoxygenation and impurity removal reactions in a hydrorefining reactor, and then the hydrorefining logistics enters the first separation and fractionation system to obtain refined high-pressure gas, naphtha, diesel and heavy oil, wherein the refined high-pressure gas refluxes into the hydrorefining reactor, and the heavy oil enters the hydrocracking reactor for hydrocracking reaction. After the reaction is completed, it enters the second separation and fractionation system, and gas, naphtha and diesel fractions are separated. The uncracked heavy components after separation are all refluxed into the hydrocracking reactor for hydrocracking reaction again. The catalyst and process conditions used are the same as those in Example 1.

[0083] Table 1 Main properties of crude oil

[0084] project data <![CDATA[Density, g / cm 3 > 0.807 Distillation range, ℃ Initial distillation point / 10% 68 / 203 30％ / 50％ 314 / 372 70％ / 90％ 461 / 558 95％ 649 Sulfur content, vol% 3.9 Nitrogen content, μg / g 3.2 Oxygen content, wt% 0.79

[0085] Table 2 Example process conditions

[0086]

[0087] Table 3 Product distribution and properties

[0088] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Naphtha fraction Distillation range, ℃ 65～160 65～160 65～160 65～160 65～160 Yield, wt% 43.1 36.7 40.2 38.5 16.8 <![CDATA[Density, g / cm 3 > 0.703 0.705 0.712 0.710 0.712 Composition, wt% Normal alkanes 88.21 87.18 85.47 88.15 84.50 Isoalkanes 10.19 11.60 12.36 10.22 12.21 Diesel fraction Distillation range, ℃ 160～370 160～370 160～370 160～370 160～370 Yield, wt% 55.2 62.8 58.1 60.7 78.1 <![CDATA[Density, g / cm 3 > 0.781 0.773 0.765 0.775 0.793 Pour point, ℃ -3 -4 -5 -5 -2 Cetane number 83 83 84 84 78

[0089] From the results in Table 3, it can be seen that the yield of naphtha using the method of the present invention is significantly higher than that of Comparative Example 1. The naphtha fraction is mainly composed of alkanes and is a high-quality raw material for steam cracking to produce ethylene and propylene.

[0090] Example 5

[0091] The laboratory simulated and calculated the bed reaction temperature distribution of the two-stage hydrogenation reactor (hydrocracking reactor) of the embodiment and comparative example by using ansys 19.0 version software. The simulation conditions were input according to the actual data of the embodiment and comparative example. The simulation results show that the center temperature of the traditional fixed bed is the highest, and the temperature change is normally distributed from the inlet end to the outlet end. The bed temperature of the reactor of the present invention is relatively uniform. The simulated temperature rise change of the bed is shown in Table 4.

[0092] Table 4 Simulated bed temperature rise changes

[0093] Bed temperature point Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Maximum radial temperature difference, ℃ 1.6 1.3 1.5 2.0 26.1 Average temperature, °C 386.0 370.9 376.1 401.2 402.7

[0094] It can be seen from the results in Table 4 that the temperature difference of the catalyst bed in Examples 1 to 3 of the present invention is significantly lower than that in Comparative Example 1, from 26.1°C of the traditional fixed bed to less than 2.0°C. The difference between the average temperature of the examples and the controlled temperature is the smallest, indicating that the reactor of the present invention has eliminated the overheating phenomenon of the hydrocracking reaction.

Claims

1. A Fischer-Tropsch synthesis oil hydrocatalytic distillation device, characterized in that: The device comprises: (1) a hydrotreating reactor, which is used to perform a hydrotreating reaction on the raw material Fischer-Tropsch synthetic oil; the stream obtained by the hydrotreating enters a catalytic reaction distillation tower; (2) a catalytic reaction distillation tower, comprising at least one catalytic reaction zone, wherein the catalytic reaction zone is a 2-n-layer tower plate structure, each tower plate is loaded with a catalyst bed, wherein n is an integer greater than 2; an inclined partition is arranged on the top of each catalyst bed; and a gas phase channel is arranged through each catalyst bed and the inclined partition; The catalytic reaction distillation tower comprises: a liquid phase feed subunit, which is arranged above the inclined partition of the topmost catalyst bed layer, through which the liquid phase feed is guided to the catalyst bed layer; a gas phase feed subunit, which is arranged between the catalyst bed layer of the upper layer and the inclined partition of the lower layer; The lower end of the gas phase channel passing through the upper catalyst bed is connected to the inclined partition on the next catalyst bed; the catalyst bed is provided with: an overflow weir, which is arranged on the side close to the gas phase channel; a liquid sealing baffle, which is arranged on the upper part of the overflow weir and is used to isolate the gas phase feed from the gas phase product; the gas phase channel is located in the middle of the catalytic reaction distillation tower and passes through all catalyst beds from bottom to top.

2. The device according to claim 1, characterized in that An annular downcomer is disposed at the end of the inclined partition, and the bottom of the annular downcomer is spaced a distance from the bottom of the catalyst bed so that the liquid feed enters the catalyst bed in a radial direction.

3. The device according to claim 1, characterized in that The liquid seal baffle comprises: a horizontal portion which is annular and flat and located above the overflow weir; a vertical portion which is cylindrical and is integrally formed with the horizontal portion, and a lower end of the vertical portion is spaced a distance from the bottom of the catalyst bed.

4. The device according to claim 1, characterized in that The liquid phase feed subunit includes: a liquid phase feed pipe, which extends in the radial direction of the catalyst bed; a liquid phase distribution pipe, which is annular and intersects orthogonally or tangentially with the liquid phase feed pipe, and the tube wall of the liquid phase distribution pipe is provided with a plurality of channels for evenly distributing the liquid phase feed to all directions of the annular downcomer.

5. The device according to claim 1, characterized in that The gas-phase feed subunit comprises: a gas-phase feed pipe, which extends in the radial direction of the catalyst bed; a gas-phase distribution pipe, which is in an annular shape or a plurality of concentric annular shapes, and the gas-phase distribution pipe intersects the gas-phase feed pipe orthogonally or tangentially, and a plurality of holes are arranged on the wall of the gas-phase distribution pipe for evenly distributing the gas-phase feed to all directions at the bottom of the catalyst bed.

6. The device according to claim 1 or 5, characterized in that The gas phase feeding subunit comprises: a gas phase distribution plate, which is located at the bottom of the catalyst bed and is in the shape of a plate as a whole, and a plurality of holes are evenly and densely distributed on the gas phase distribution plate.

7. The device according to claim 1, characterized in that The upper edge of the overflow weir is 10 to 100 mm higher than the upper surface of the catalyst in this bed.

8. The device according to claim 1, characterized in that The catalytic reaction distillation tower is provided with a separation zone at the top; the ratio of the number of catalyst beds in the separation zone to that in the catalytic reaction zone is 1:1 to 1:n-1; fillers or hydrocracking catalysts are selectively placed on the catalyst beds in the separation zone; and the hydrocracking catalysts are loaded on the catalyst beds in the catalytic reaction zone.

9. A method for hydrogenating Fischer-Tropsch oil using the device according to any one of claims 1 to 8, comprising the following steps: (1) The Fischer-Tropsch synthetic oil is mixed with hydrogen and then enters a hydrotreating reactor to undergo a hydrotreating reaction under the action of a hydrotreating catalyst; (2) The logistics obtained by the hydrotreating in step (1) enters a catalytic reaction distillation tower, descends in the tower and sequentially enters a plurality of catalyst beds, and contacts and reacts with the hydrogen entering the catalyst beds upward; the gaseous product obtained by the reaction of each catalyst bed enters a gas phase channel, and flows upward out of the catalytic reaction distillation tower in the gas phase channel; the liquid product obtained by the reaction of each catalyst bed sequentially enters the next catalyst bed to react, and the final liquid product flows downward out of the catalytic reaction distillation tower.

10. The method according to claim 9, characterized in that The hydroprocessing refined material flows into the catalytic reaction distillation tower, and first enters the separation zone when going down in the tower, and is separated into light components and heavy components. The heavy components move downward into the catalyst bed to react, and the light components are directly mixed with the gas phase products and flow out of the catalytic reaction distillation tower from the top.

11. The method according to claim 9, characterized in that The operating conditions of the Fischer-Tropsch synthetic oil hydrofining process in step (1) are as follows: reaction temperature is 200°C to 400°C, reaction pressure is 3MPa to 18MPa, hydrogen-to-oil volume ratio is 100 to 1000, liquid hourly volume space velocity is 0.5h -1 ~10.0h -1 .

12. The method according to claim 9, characterized in that The operating conditions of the catalytic reaction distillation tower in step (2) are as follows: reaction temperature is 260°C to 450°C, reaction pressure is 3MPa to 20MPa, hydrogen to oil volume ratio is 100 to 2000, liquid hourly volume space velocity is 0.1h -1 ~10.0h -1 .

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