Tubular Fischer-Tropsch synthesis reactor and synthesis process
The tubular FeTO synthesis reactor addresses heat management and temperature distribution issues with coupled heat exchange systems, enhancing efficiency and catalyst lifespan for compact designs.
Patent Information
- Application Number
- CN202510644877.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-19
- Publication Date
- 2025-07-15
AI Technical Summary
Traditional Fischer Tropsch synthesis reactors have problems such as poor heat exchange effect, local overheating of the catalyst bed and uneven temperature distribution, which affects the reaction efficiency and catalyst life, and are large in size and are not suitable for distributed and small-scale applications.
The column-type Fischer-Tropsch synthesis reactor is adopted, through the coupling heat exchange method of the first medium and the second medium, hot air and hot oil respectively provide or absorb heat in the pretreatment and reaction stages, achieving accurate temperature control and efficient heat exchange. Combined with the parallel arrangement design of the reaction tube, the structure is simplified and the process conditions are flexibly adjusted.
It realizes precise temperature control in wide temperature zones, improves reaction efficiency and catalyst life, is suitable for distributed and small-scale application scenarios, and reduces maintenance and operation complexity.
Smart Images
Figure CN120310583A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of chemical reactors, and more specifically, to a shell-and-tube Fischer-Tropsch synthesis reactor and a synthesis process. Background Art
[0002] Fischer-Tropsch synthesis is a core process that converts coal, natural gas or biomass into synthesis gas (CO and H2), which is then converted to liquid hydrocarbons and oxygenated compounds at a temperature of 180°C-400°C over iron-based, cobalt-based, ruthenium-based and other catalysts. Traditional Fischer-Tropsch synthesis reactors have some shortcomings in the process of converting synthesis gas into liquid hydrocarbons and oxygenated compounds: First, due to the strong exothermic characteristics of the reaction process (ΔH≈-165kJ / mol), existing reactors have thermal management problems, which can easily cause local overheating, resulting in a shortened catalyst life and a decrease in the selectivity of liquid hydrocarbons and oxygenated compounds; second, traditional reactors are bulky, with high investment and operating costs, which seriously restricts their economic feasibility in distributed and small-scale application scenarios.
[0003] Traditional fixed-bed and slurry-bed Fischer-Tropsch synthesis reactors each have their own limitations. The main disadvantages of fixed-bed reactors include: poor heat transfer performance, easy formation of hot spots during the reaction, resulting in local overheating of the catalyst and subsequent sintering and deactivation; uneven temperature distribution in the reactor, affecting product selectivity and yield; catalyst replacement and regeneration are relatively complicated, increasing downtime and maintenance costs. The disadvantages of slurry-bed reactors are: the separation of catalyst and liquid medium is more difficult, increasing the complexity of subsequent treatment; uneven mixing of gas, liquid and solid phases in the reactor, resulting in reduced reaction efficiency; severe equipment wear, especially wear of internal components, increasing maintenance and replacement frequency; relatively complex operating conditions, and high requirements for process control; large reactor volume, making it difficult to achieve compact design.
[0004] In general, both reactors have certain challenges in terms of heat transfer, mass transfer, catalyst management, compact design and operation. Although the existing shell-and-tube Fischer-Tropsch synthesis reactor has achieved compact design to a certain extent and reduced the reactor volume, it still has problems such as poor heat exchange effect, local overheating of the catalyst bed and uneven temperature distribution, making it difficult to meet the needs of efficient Fischer-Tropsch synthesis.
[0005] Therefore, how to improve the problems of poor heat exchange, local overheating of the catalyst bed and uneven temperature distribution to improve the reaction efficiency has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention
[0006] In view of this, the purpose of the present application is to provide a shell-and-tube Fischer-Tropsch synthesis reactor to improve the problems of poor heat exchange, local overheating of the catalyst bed and uneven temperature distribution, so as to improve the reaction efficiency.
[0007] Another core of the present application lies in disclosing a shell-and-tube Fischer-Tropsch synthesis process using the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor.
[0008] To achieve the above object, the present application provides the following technical solutions:
[0009] A shell-and-tube Fischer-Tropsch synthesis reactor includes a first head, a reactor shell, and a second head connected in sequence. A syngas inlet is provided on the first head, and a gas distributor communicating with the syngas inlet is provided inside the first head; a reaction product outlet is provided at the bottom of the second head;
[0010] A plurality of reaction tubes arranged in parallel and capable of loading catalysts are provided inside the reactor shell, and each reaction tube is disposed between the first head and the second head; a first medium inlet, a first medium outlet, a second medium inlet, and a second medium outlet are provided on the reactor shell, the first medium inlet and the first medium outlet are oppositely arranged, and the second medium inlet and the second medium outlet are oppositely arranged;
[0011] The first medium inlet and the first medium outlet are connected to a first medium heat exchange system, and the first medium heat exchange system can provide the first medium. The second medium inlet and the second medium outlet are connected to a second medium heat exchange system, and the second medium heat exchange system can provide the second medium;
[0012] The first medium is air or nitrogen or steam or helium or argon; and / or, the second medium is mineral oil or Dowtherm oil or hydrogenated terphenyl or silicone-based heat transfer oil or molten salt or ionic liquid.
[0013] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, the height of the first medium inlet is higher than the height of the first medium outlet; or, the height of the first medium inlet is lower than the height of the first medium outlet;
[0014] The height of the second medium inlet is lower than the height of the second medium outlet.
[0015] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, an expansion joint is provided on the reactor shell.
[0016] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, a safety valve and a nitrogen inlet are provided at the top of the first head, and the nitrogen inlet is connected to a nitrogen supply assembly.
[0017] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, a catalyst baffle and a support are provided inside the second head, the support supports each reaction tube, and the catalyst baffle is disposed at the lower part of each reaction tube.
[0018] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, an exhaust port is provided at the top of the reactor shell, and a drain port is provided at the bottom of the reactor shell.
[0019] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor, the first medium heat exchange system includes a first heater, a fan, a first pipeline, a second pipeline, and a first temperature control component. The fan is arranged on the first pipeline or the second pipeline. One end of the first pipeline is connected to the outlet of the first heater, and the other end communicates with the first medium inlet. One end of the second pipeline is connected to the inlet of the first heater, and the other end communicates with the first medium outlet. The temperature control component can measure and regulate the temperature of the first medium; and / or, the second medium heat exchange system includes a second heater, a pump, a third pipeline, a fourth pipeline, and a second temperature control component. The pump is arranged on the third pipeline or the fourth pipeline. One end of the third pipeline is connected to the outlet of the second heater, and the other end communicates with the second medium inlet. One end of the fourth pipeline is connected to the inlet of the heater, and the other end communicates with the second medium outlet. The second temperature control component can measure and regulate the temperature of the second medium.
[0020] A shell-and-tube Fischer-Tropsch synthesis process uses the above-mentioned shell-and-tube Fischer-Tropsch synthesis reactor and includes the following steps:
[0021] S1. Catalyst pretreatment: Introduce the first medium or the second medium into the reactor shell, introduce a reducing gas into the reaction tubes, and perform a reduction treatment on the catalyst in the reaction tubes at a first preset temperature and a preset pressure to make the catalyst active.
[0022] S2. Fischer-Tropsch synthesis reaction: The syngas enters the reaction tubes from the syngas inlet and reacts with the catalyst in the reaction tubes.
[0023] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis process, the Fischer-Tropsch synthesis reaction step specifically includes:
[0024] S21. Reactor feeding: Select several reaction tubes filled with catalyst to participate in the reaction. The syngas enters the selected reaction tubes from the syngas inlet, passes through the gas distributor and the first head in sequence.
[0025] S22. Introduce the first medium or the second medium into the reactor shell, and turn on the first medium heat exchange system or the second medium heat exchange system so that the first medium or the second medium enters the reactor shell and the temperature in the reactor shell is the second preset temperature.
[0026] S23. Reaction occurs: The syngas undergoes a Fischer-Tropsch synthesis reaction under the action of the catalyst to generate hydrocarbons and oxygen-containing compounds.
[0027] S24. Reactant discharge: The generated reactants are discharged from the reaction product outlet.
[0028] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis process, if the medium introduced into the reactor shell in step S22 is the first medium, then after step S23, there is also a step of introducing a second medium into the reactor shell. After the reaction is started, the first medium heat exchange system is closed, and the second medium heat exchange system is opened, so that the temperature of the reactor shell is the second preset temperature.
[0029] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis process, the first preset temperature is 250°C - 450°C, and the preset pressure is 0 - 5.0 Mpa; and / or, the second preset temperature is 180°C - 400°C.
[0030] Optionally, in the above-mentioned shell-and-tube Fischer-Tropsch synthesis process, there is also a step S3 of catalyst regeneration. When the activity and selectivity of the catalyst decline, the catalyst in the reaction tube is regenerated to restore its activity.
[0031] As can be seen from the above solutions, the shell-and-tube Fischer-Tropsch synthesis reactor and the shell-and-tube Fischer-Tropsch synthesis process disclosed in the embodiments of the present application have the following beneficial effects: 1. It can achieve precise temperature control in a wide temperature range. Through the coupled heat exchange method of the first medium and the second medium (preferably the coupling of hot air and hot oil), it can meet the precise control of different temperature requirements in the pretreatment stage and the reaction stage; 2. High-efficiency heat exchange and dynamic thermal management: Through the heat exchange method of the second medium (hot oil), it can improve the heat transfer efficiency of the Fischer-Tropsch synthesis reactor, reduce the problems of local overheating and uneven temperature distribution in the catalyst bed layer, and can extend the service life of the catalyst and improve the reaction efficiency; 3. Flexible process: The process conditions are flexibly controllable. The first medium or the second medium can be selected according to needs, and the reaction temperature, pressure and gas flow can be flexibly adjusted to improve the product selectivity and yield; 4. Compact structure: By adopting the parallel arrangement of reaction tubes, the Fischer-Tropsch synthesis reactor has a simple structure, is easy to maintain and operate, is suitable for distributed skid-mounted devices and small-scale application scenarios, and provides an ideal solution for the efficient conversion of medium and small-scale natural gas, biomass and other carbon-containing resources. Description of the Drawings
[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0033] Figure 1 It is a schematic structural diagram of the shell-and-tube Fischer-Tropsch synthesis reactor disclosed in the embodiments of the present application;
[0034] Figure 2 It is the process flow of the shell-and-tube Fischer-Tropsch synthesis reactor process disclosed in the embodiments of the present applicationFigure 1 ;
[0035] Figure 3 is a flow chart of the Fischer - Tropsch synthesis reaction disclosed in the embodiments of the present application;
[0036] Figure 4 is the process flow of the shell - and - tube Fischer - Tropsch synthesis reactor disclosed in the embodiments of the present application Figure 2 .
[0037] Among them, 10 is the first head, 11 is the syngas inlet, 12 is the gas distributor, 13 is the installation port for the pressure gauge and thermometer, and 14 is the installation port for the safety valve;
[0038] 20 is the reactor shell, 21 is the reaction tube, 22 is the first medium inlet, 23 is the first medium outlet, 24 is the second medium inlet, 25 is the second medium outlet, 26 is the exhaust port, 27 is the drain port, and 28 is the expansion joint;
[0039] 30 is the second head, 31 is the reaction product outlet, 32 is the support, 33 is the catalyst baffle, and 34 is the flange. Specific embodiments
[0040] The core of the present application lies in disclosing a shell - and - tube Fischer - Tropsch synthesis reactor to improve the problems of poor heat exchange effect, local overheating of the catalyst bed, and uneven temperature distribution, so as to improve the reaction efficiency.
[0041] Another core of the present application lies in disclosing a shell - and - tube Fischer - Tropsch synthesis process using the above - mentioned shell - and - tube Fischer - Tropsch synthesis reactor.
[0042] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.
[0043] As Figure 1 shown, the embodiments of the present application disclose a shell - and - tube Fischer - Tropsch synthesis reactor, including a first head 10, a reactor shell 20, and a second head 30 connected in sequence.
[0044] Specifically, a syngas inlet 11 is provided on the first head 10, a gas distributor 12 communicating with the syngas inlet 11 is provided inside the first head 10, and a reaction product outlet 31 is provided at the bottom of the second head 30. A plurality of reaction tubes 21 arranged in parallel and capable of loading catalysts are provided inside the reactor shell 20, and each reaction tube 21 is arranged between the first head 10 and the second head 30; a first medium inlet 22, a first medium outlet 23, a second medium inlet 24 and a second medium outlet 25 are provided on the reactor shell 20, the first medium inlet 22 and the first medium outlet 23 are oppositely arranged, and the second medium inlet 24 and the second medium outlet 25 are oppositely arranged.
[0045] The first medium inlet 22 and the first medium outlet 23 are connected to a first medium heat exchange system, the first medium heat exchange system can provide a first medium, the second medium inlet 24 and the second medium outlet 25 are connected to a second medium heat exchange system, the second medium heat exchange system can provide a second medium, and the first medium heat exchange system and the second medium heat exchange system can work independently. The first medium is air or nitrogen or steam or helium or argon; and / or, the second medium is mineral oil or Dowtherm oil or hydrogenated terphenyl or silicone-based heat transfer oil or molten salt or ionic liquid.
[0046] It should be noted that the catalysts loaded in the reaction tubes 21 include iron-based, cobalt-based or ruthenium-based catalysts, etc., and the specific types of catalysts can be specifically selected according to the actual situation.
[0047] During actual use, first, the catalyst needs to be pretreated. At this time, the first medium or the second medium can be flexibly selected and introduced into the reactor shell 20 according to the temperature required for the catalyst pretreatment to heat the reaction tubes 21. The first medium or the second medium and the catalyst adopt a wall-to-wall heat exchange method to provide or absorb heat for the pretreatment of the catalyst to provide an appropriate temperature. A reducing gas (including hydrogen or carbon monoxide or syngas) is introduced into the reaction tubes 21, and the catalyst is reduced to reduce the metal oxide to metal, making the catalyst catalytically active. Preferably, the first medium (hot air) is used to provide or absorb heat for each reaction tube 21.
[0048] After the catalyst pretreatment is completed, syngas is introduced into the reaction tube 21. The syngas enters the gas distributor 12 from the syngas inlet 11, and after being evenly distributed by the gas distributor 12, it enters each reaction tube 21. According to actual needs, the first medium or the second medium is selected to be introduced into the reactor shell 20 to provide or absorb heat for the Fischer-Tropsch synthesis reaction to provide an appropriate reaction temperature. The first medium or the second medium can be flexibly selected according to the actual temperature requirements. In order to improve the uniformity of the temperature distribution in the reactor, it is preferred to use the second medium (hot oil) to provide or absorb heat for the Fischer-Tropsch synthesis reaction of syngas. The setting of the gas distributor 12 can reduce local hot spots and temperature runaway, improve the radial or axial temperature uniformity of the reactor, optimize the contact efficiency between the syngas and the catalyst, enhance mass transfer, and can also reduce the abrasion of the catalyst by the high-speed syngas flow and extend the service life of the catalyst.
[0049] Preferably, in the catalyst pretreatment stage, the first medium is selected as the heating medium. The first medium is preferably air, hereinafter referred to as hot air; in the Fischer-Tropsch synthesis reaction stage, the second medium is selected as the heating medium. The second medium is preferably oil, hereinafter referred to as hot oil. The hot oil and hot air can achieve the control of the catalyst pretreatment and reaction temperature above 350°C. The first medium or the second medium can be flexibly selected to be introduced into the reactor shell 20 according to the required temperature of the pretreated catalyst.
[0050] The shell-and-tube Fischer-Tropsch synthesis reactor disclosed in the embodiments of the present application has the following beneficial effects: 1. It can achieve precise temperature control in a wide temperature range. Through the coupled heat exchange method of the first medium and the second medium (preferably the coupling of hot air and hot oil), it can meet the precise control of different temperature requirements in the pretreatment stage and the reaction stage; 2. High-efficiency heat exchange and dynamic thermal management: Through the heat exchange method of the second medium (hot oil), it can improve the heat transfer efficiency of the Fischer-Tropsch synthesis reactor, reduce the problems of local overheating and uneven temperature distribution in the catalyst bed layer, and can extend the service life of the catalyst and improve the reaction efficiency; 3. Flexible process: The process conditions are flexibly controllable. The first medium or the second medium can be selected according to needs, and the reaction temperature, pressure and gas flow can be flexibly adjusted to improve the product selectivity and yield; 4. Compact structure: By adopting the parallel arrangement of the reaction tubes 21, the Fischer-Tropsch synthesis reactor has a simple structure, is easy to maintain and operate, is suitable for distributed skid-mounted devices and small-scale application scenarios, and provides an ideal solution for the efficient conversion of medium and small-scale natural gas, biomass and other carbon-containing resources.
[0051] Furthermore, tube sheets are provided inside both the first head 10 and the second head 30. Both ends of each reaction tube 21 are connected to the tube sheet. To ensure the sealing performance and prevent the syngas inside the reaction tube 21 from entering the reactor shell 20, a gap seal is adopted at the connection between the reaction tube 21 and the tube sheet. Specifically, the reaction tube 21 and the tube sheet can be connected by an expansion joint connection method, or by a welding connection method, or sealed by a sealant or packing.
[0052] Furthermore, the first head 10, the tube sheet, and the reactor shell 20 are connected by a flange 34, and the reactor shell 20, the tube sheet, and the second head 30 are connected by a flange 34. The flange connection method is convenient for disassembly and assembly and is conducive to maintenance and repair.
[0053] Furthermore, as Figure 1 shown, the height of the first medium inlet 22 is higher than the height of the first medium outlet 23; or, the height of the first medium inlet 22 is lower than the height of the first medium outlet 23; the height of the second medium inlet 24 is lower than the height of the second medium outlet 25. That is, when the first medium provides or absorbs heat for the catalyst pretreatment or Fischer-Tropsch synthesis reaction, the first medium can flow in from top to bottom or from bottom to top, and the way of flowing in from bottom to top is preferred; when the second medium provides or absorbs heat for the catalyst pretreatment or Fischer-Tropsch synthesis reaction, to ensure the heat exchange effect, the second medium preferably flows in from bottom to top. Since the syngas flows from top to bottom, to improve the heat exchange effect, both the first medium and the second medium preferably flow in from bottom to top to achieve countercurrent heat exchange.
[0054] Furthermore, to ensure the safe and stable operation of the Fischer-Tropsch synthesis reactor, an expansion joint 28 is provided on the reactor shell 20. Specifically, the expansion joint 28 is provided on the outer wall of the reactor shell 20. The setting of the expansion joint 28 can absorb the displacement of the reactor shell 20 during heating or cooling through flexible deformation, ensure the close contact of the flange sealing surface, reduce the cracking, deformation or damage of the reactor shell 20 due to excessive stress, and can reduce the occurrence of air leakage in the Fischer-Tropsch synthesis reactor; when the reaction pressure suddenly changes (such as start-up and shutdown, catalyst regeneration), the setting of the expansion joint 28 can reduce the damage of the pressure shock to the reactor shell 20. Specifically, the expansion joint 28 can be arranged along the circumferential direction of the reactor shell 20, and at this time the expansion joint 28 can absorb the radial displacement; or, the expansion joint 28 can be arranged along the axial direction of the reactor shell 20, and at this time the expansion joint 28 can absorb the axial displacement; or, on a certain section along the circumferential direction of the reactor shell 20, the expansion joint 28 is locally provided, and the specific setting method can be determined according to the actual situation.
[0055] Furthermore, to reduce the occurrence of safety accidents, a safety valve is provided at the top of the first head 10, as Figure 1As shown in the figure, a safety valve installation port 14 and a nitrogen inlet are provided at the top of the first head 10. The safety valve is installed on the safety valve installation port 14, preferably in a flange connection manner. The nitrogen inlet is connected to the nitrogen supply assembly. When the pressure or temperature of the syngas rapidly increases and exceeds the set pressure of the safety valve, the safety valve opens, the exhaust port is conducted, and the syngas is discharged. At this time, the nitrogen supply assembly is activated to supply nitrogen into the Fischer-Tropsch synthesis reactor, cutting off the Fischer-Tropsch synthesis reaction and reducing the occurrence of safety accidents. In order to measure the pressure and temperature inside the reactor, a pressure gauge and a thermometer installation port 13 are provided on the first head 10 for installing a thermometer and a pressure gauge. The specific types of the thermometer and the pressure gauge can be specifically selected according to actual requirements.
[0056] Furthermore, in order to collect the catalyst that falls from each reaction tube 21 into the second head 30, a catalyst baffle 33 is provided in the second head 30. The catalyst baffle 33 is provided with filter holes through which the products generated by the Fischer-Tropsch synthesis reaction can pass, but can block the catalyst. The catalyst baffle 33 is preferably detachably connected to the second head 30 to facilitate the recycling of the collected catalyst. In order to support each reaction tube 21 and ensure the structural stability, a support member 32 is provided in the second head 30. Here, the support member 32 can be a tube sheet or a support plate connected to the tube sheet.
[0057] Furthermore, in order to discharge the gas or liquid inside the reactor shell 20, an exhaust port 26 is provided at the top of the reactor shell 20, and a drain port 27 is provided at the bottom of the reactor shell 20.
[0058] Furthermore, in some specific embodiments, the first medium heat exchange system includes a first heater, a blower, a first pipe, a second pipe, and a first temperature control component. The blower is provided on the first pipe or the second pipe. One end of the first pipe is connected to the outlet of the first heater, and the other end communicates with the first medium inlet 22. One end of the second pipe is connected to the inlet of the first heater, and the other end communicates with the first medium outlet 23. The first heater is provided with a first medium inlet. The first temperature control component can measure and regulate the temperature of the first medium. If the first medium is air and the blower provides power, there is an air inlet on the first heater. After the first heater heats the air, the heated air (hereinafter referred to as hot air) enters the reactor shell 20 through the first pipe via the first medium inlet 22, provides heat to the reaction tubes 21, and then flows out through the first medium outlet 23 and returns to the first heater through the second pipe for heating and then circulates the above process.
[0059] The first temperature control assembly specifically includes a first temperature measuring element disposed on the first pipeline and a first regulating valve disposed on the first pipeline or the second pipeline. The first temperature measuring element can measure the temperature of the first medium entering the reactor housing 20, and the opening degree of the first regulating valve can be adjusted to change the flow rate of the first medium entering the reactor housing 20. The first temperature measuring element is interlocked with the first regulating valve, and the temperature measured by the first temperature measuring element can be fed back to the first regulating valve, thereby adjusting the opening degree of the first regulating valve. The first temperature measuring assembly may include a second temperature measuring element disposed in the reactor housing 20 for measuring the temperature in the reactor housing 20. The second temperature measuring element is interlocked with the first regulating valve, and the opening degree of the first regulating valve can be adjusted according to the temperature measured by the second temperature measuring element. It should be noted that the type of the first heater is not specifically limited and can be selected according to actual needs. Alternatively, a second regulating valve is disposed on the first pipeline or the second pipeline, and the second temperature measuring element is interlocked with the second regulating valve.
[0060] In some specific embodiments, the second medium heat exchange system includes a second heater, a pump, a third pipeline, a fourth pipeline, and a second temperature control assembly. The pump is disposed on the third pipeline or the fourth pipeline. One end of the third pipeline is connected to the outlet of the second heater, and the other end communicates with the second medium inlet 24. One end of the fourth pipeline is connected to the inlet of the heater, and the other end communicates with the second medium outlet 25. A second medium inlet is provided on the second heater, and the second temperature control assembly can measure and control the temperature of the second medium. Taking the second medium as oil (hot oil) as an example, the water pump provides power. The hot oil flows out of the second heater, enters the reactor housing 20 through the third pipeline from the second medium inlet 24, and heats the catalyst or the syngas and the catalyst in each reaction tube 21 to complete the pretreatment process of the catalyst or the Fischer-Tropsch synthesis reaction process; the hot oil flowing out of the second medium outlet 25 flows back into the second heater through the fourth pipeline for heating and then recycled.
[0061] The second temperature control assembly includes a third temperature measuring element disposed on the third pipeline and a third regulating valve disposed on the third pipeline or the fourth pipeline. The third temperature measuring element can measure the temperature of the second medium entering the reactor housing 20, and the opening degree of the third regulating valve can be adjusted to change the flow rate of the second medium entering the reactor housing 20. The third temperature measuring element is interlocked with the third regulating valve, and the temperature measured by the third temperature measuring element can be fed back to the third regulating valve, thereby adjusting the opening degree of the third regulating valve. The second temperature measuring assembly may include a fourth regulating valve disposed on the third pipeline or the fourth pipeline, and the second temperature measuring element is interlocked with the fourth regulating valve.
[0062] Further, as Figure 2As shown in the figure, the embodiment of the present application also discloses a shell-and-tube Fischer-Tropsch synthesis process, which uses the shell-and-tube Fischer-Tropsch synthesis reactor of the above embodiment and includes the following steps:
[0063] S1. Catalyst pretreatment;
[0064] Introduce the first medium or the second medium into the reactor shell 20, introduce a reducing gas into the reaction tube 21, and perform a reduction treatment on the catalyst in the reaction tube 21 at the first preset temperature and the preset pressure to make the catalyst active. Specifically, the first medium or the second medium introduced into the reactor shell 20 can be flexibly selected according to the temperature required in the catalyst pretreatment process. Preferably, during the catalyst pretreatment process, the catalyst in the reaction tube 21 is heated by the first medium (hot air), and the uniform heating and activation of the catalyst are realized by using the convection characteristics of the hot air. Since the maximum heating temperature of the second medium (hot oil) is 350°C, when the temperature required in the catalyst pretreatment process is relatively high, the second medium cannot meet the requirements. Therefore, it is preferred to introduce the first medium (hot air) to pretreat the catalyst.
[0065] S2. Fischer-Tropsch synthesis reaction;
[0066] The syngas enters the reaction tube 21 from the syngas inlet 11 and reacts with the catalyst in the reaction tube 21.
[0067] As Figure 3 shown, step S2 specifically includes the following steps:
[0068] S21. Reactor feeding;
[0069] Select several reaction tubes 21 filled with catalyst to participate in the reaction. The syngas enters each selected reaction tube 21 from the syngas inlet 11 through the gas distributor 12 and the first head 10 in sequence. Specifically, in order to be able to select the reaction tubes 21 targeted according to the catalyst packing, valves can be provided on each reaction tube 21, and the reaction tubes 21 participating in the reaction are selected according to the opening and closing of the valves. The valves are preferably electrically controlled valves. Of course, all reaction tubes 21 can also participate in the reaction.
[0070] S22. Introduce the first medium or the second medium into the reactor shell 20, and turn on the first medium heat exchange system or the second medium heat exchange system, so that the first medium or the second medium enters the reactor shell 20, and the temperature in the reactor shell 20 is the second preset temperature. Here, the first medium or the second medium introduced can be flexibly selected according to the actual situation. In order to better control the reactor bed temperature, it is preferred to introduce the second medium (hot oil) to provide or absorb heat for each reaction tube 21.
[0071] S23. React;
[0072] The syngas undergoes the Fischer-Tropsch synthesis reaction under the action of a catalyst to produce hydrocarbons and oxygenates.
[0073] S24. Discharge of reactants;
[0074] The generated reactants are discharged from the reaction product outlet 31 and enter the subsequent separation and purification system.
[0075] Furthermore, in order to optimize the temperature distribution in the reactor, if the medium introduced into the reactor shell 20 in step S23 is the first medium (hot air), then after step S23, it also includes the step of introducing the second medium (hot oil) into the reactor shell 20. After the reaction is started, the first medium heat exchange system is closed and the second medium heat exchange system is opened, so that the temperature in the reactor shell 20 is the second preset temperature, ensuring that the reaction proceeds under the best conditions. Since the thermal conductivity of the liquid is relatively high, using the second medium (hot oil) is beneficial to better control the temperature of the reactor bed layer, optimize the reactor temperature distribution, and then extend the catalyst life and improve the selectivity and yield of the target product.
[0076] Furthermore, the first preset temperature is 250°C - 450°C, and the preset pressure is 0 - 5.0 Mpa; and / or, the second preset temperature is 180°C - 400°C, and the reaction pressure is 0 - 5.0 Mpa.
[0077] Furthermore, as Figure 4 shown, the tubular Fischer-Tropsch synthesis process also includes step S3, catalyst regeneration. When the activity and selectivity of the catalyst decline, the catalyst in the reaction tube 21 is regenerated to restore its activity. The specific method of catalyst regeneration here can refer to the existing regeneration methods and will not be elaborated here.
[0078] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.
[0079] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.
[0080] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the core idea of the present application. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.
Claims
1. A shell-and-tube Fischer-Tropsch synthesis reactor, characterized in that, It includes a first head (10), a reactor shell (20) and a second head (30) connected in sequence. A syngas inlet (11) is provided on the first head (10), and a gas distributor (12) communicating with the syngas inlet (11) is provided inside the first head (10); a reaction product outlet (31) is provided at the bottom of the second head (30). A plurality of reaction tubes (21) arranged in parallel and capable of loading catalysts are provided inside the reactor shell (20), and each of the reaction tubes (21) is arranged between the first head (10) and the second head (30); a first medium inlet (22), a first medium outlet (23), a second medium inlet (24) and a second medium outlet (25) are provided on the reactor shell (20), the first medium inlet (22) and the first medium outlet (23) are oppositely arranged, and the second medium inlet (24) and the second medium outlet (25) are oppositely arranged. The first medium inlet (22) and the first medium outlet (23) are connected to a first medium heat exchange system, and the first medium heat exchange system can provide a first medium. The second medium inlet (24) and the second medium outlet (25) are connected to a second medium heat exchange system, and the second medium heat exchange system can provide a second medium. The first medium is air or nitrogen or steam or helium or argon; and / or, the second medium is mineral oil or Dowtherm oil or hydrogenated terphenyl or silicone-based heat transfer oil or molten salt or ionic liquid.
2. The shell-and-tube Fischer-Tropsch synthesis reactor according to claim 1, wherein, The height of the first medium inlet (22) is higher than the height of the first medium outlet (23); or, the height of the first medium inlet (22) is lower than the height of the first medium outlet (23). The height of the second medium inlet (24) is lower than the height of the second medium outlet (25).
3. The tubular Fischer-Tropsch synthesis reactor according to claim 1, characterized in that, An expansion joint (28) is provided on the reactor shell (20).
4. The shell-and-tube Fischer-Tropsch synthesis reactor according to claim 1, wherein, A safety valve and a nitrogen inlet are provided at the top of the first head (10), and the nitrogen inlet is connected to a nitrogen supply assembly.
5. The shell-and-tube Fischer-Tropsch synthesis reactor according to claim 1, wherein A catalyst baffle (33) and a support (32) are provided inside the second head (30). The support (32) supports each of the reaction tubes (21), and the catalyst baffle (33) is provided at the lower part of each of the reaction tubes (21).
6. The shell-and-tube Fischer-Tropsch synthesis reactor according to claim 2, wherein, An exhaust port (26) is provided at the top of the reactor shell (20), and a drain port (27) is provided at the bottom of the reactor shell (20).
7. The shell-and-tube Fischer-Tropsch synthesis reactor according to claim 2, wherein The first medium heat exchange system includes a first heater, a blower, a first pipeline, a second pipeline, and a first temperature control component. The blower is disposed on the first pipeline or the second pipeline. One end of the first pipeline is connected to the outlet of the first heater, and the other end communicates with the first medium inlet (22). One end of the second pipeline is connected to the inlet of the first heater, and the other end communicates with the first medium outlet (23). The temperature control component can measure and regulate the temperature of the first medium; and / or, the second medium heat exchange system includes a second heater, a pump, a third pipeline, a fourth pipeline, and a second temperature control component. The pump is disposed on the third pipeline or the fourth pipeline. One end of the third pipeline is connected to the outlet of the second heater, and the other end communicates with the second medium inlet (24). One end of the fourth pipeline is connected to the inlet of the heater, and the other end communicates with the second medium outlet (25). The second temperature control component can measure and regulate the temperature of the second medium.
8. A tubular Fischer-Tropsch synthesis process using the tubular Fischer-Tropsch synthesis reactor according to any one of claims 1-7, characterized in that, The method includes the following steps: S1. Catalyst pretreatment: Introduce a first medium or a second medium into the reactor housing (20), introduce a reducing gas into the reaction tube (21), and perform a reduction treatment on the catalyst in the reaction tube (21) at a first preset temperature and a preset pressure to make the catalyst active. S2. Fischer-Tropsch synthesis reaction: Syngas enters the reaction tube (21) from the syngas inlet (11) and reacts with the catalyst in the reaction tube (21).
9. The tubular Fischer-Tropsch synthesis process according to claim 8, characterized in that, The Fischer-Tropsch synthesis reaction step specifically includes: S21. Reactor feeding: Select several reaction tubes (21) filled with catalyst to participate in the reaction. Syngas enters each selected reaction tube (21) from the syngas inlet (11) through the gas distributor (12) and the first head (10) in sequence. S22. Introduce a first medium or a second medium into the reactor housing (20), start the first medium heat exchange system or the second medium heat exchange system, so that the first medium or the second medium enters the reactor housing (20), and make the temperature in the reactor housing (20) be a second preset temperature. S23. Reaction occurs: Syngas undergoes a Fischer-Tropsch synthesis reaction under the action of the catalyst to generate hydrocarbons and oxygen-containing compounds. S24. Reactant discharge: The generated reactants are discharged from the reaction product outlet (31).
10. The tubular Fischer-Tropsch synthesis process according to claim 9, characterized in that, If in step S22, the medium introduced into the reactor housing (20) is the first medium, then after step S23, the method further includes the step of introducing a second medium into the reactor housing (20). After the reaction is started, the first medium heat exchange system is closed, and the second medium heat exchange system is started, so that the temperature of the reactor housing (20) is the second preset temperature.
11. The shell-and-tube Fischer-Tropsch synthesis process according to claim 9, characterized in that, The first preset temperature is 250°C - 450°C, and the preset pressure is 0 - 5.0 Mpa; and / or, the second preset temperature is 180°C - 400°C.
12. The tubular Fischer-Tropsch synthesis process according to claim 8, characterized in that, It further includes step S3, catalyst regeneration. After the activity and selectivity of the catalyst decline, the catalyst in the reaction tube (21) is regenerated to restore its activity.