Fixed bed online reaction evaluation system

Abstract

The invention discloses a fixed bed on-line reaction evaluation system, and relates to the technical field of fixed beds, the fixed bed on-line reaction evaluation system comprises a fixed bed reaction device and a product analysis device, the fixed bed reaction device comprises a reaction channel, a catalyst is arranged in the reaction channel for reaction of reaction gas, and a gas outlet of the reaction channel is used for introducing a gas product; the product analysis device comprises a multi-channel switching valve, a sample injection valve and a gas chromatograph, a plurality of reaction channels are arranged and are in one-to-one correspondence with feed ports of the multi-channel switching valve, and gas outlets of the reaction channels are communicated with the feed ports of the corresponding multi-channel switching valve; a discharge port of the multi-channel switching valve is communicated with a sample injection port of the gas chromatograph through the sample injection valve, the multi-channel switching valve can enable gas products of all the reaction channels to sequentially enter the gas chromatograph for analysis, and the sample injection valve can enable the gas products of all the reaction channels to regularly enter the gas chromatograph for analysis; and evaluating the catalyst of each reaction channel.

Description

Technical Field

[0001] The present invention relates to the technical field of fixed beds, in particular to a fixed bed online reaction evaluation system. Background Art

[0002] Industries involving significant carbon emissions, such as chemicals, energy, and environmental protection, have begun investing heavily in the research and development of new, efficient catalysts and adsorbents to improve carbon resource utilization, injecting new vitality into the market for related scientific research equipment. Fixed-bed reactors are widely used due to their ease of operation and flexible form factors.

[0003] At present, the existing fixed-bed reaction evaluation device has great limitations and is difficult to adapt to the fast-paced scientific research process. The main reasons are that the number of channels is small, and manual sampling and analysis are used. The errors of manual control of experimental parameters are large. During the evaluation experiment, staff are required to be on duty all the time, which consumes a lot of manpower and greatly reduces the efficiency and accuracy of the fixed-bed reaction evaluation device. Summary of the Invention

[0004] The purpose of the present invention is to provide a fixed bed online reaction evaluation system to solve the problems existing in the above-mentioned related technologies, realize fully automatic timed sampling analysis of multi-channel products, and have high experimental efficiency and small error.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a fixed bed online reaction evaluation system, comprising a fixed bed reaction device and a product analysis device, wherein the fixed bed reaction device comprises a reaction channel, an air inlet of the reaction channel is used to introduce reaction gas, a catalyst is arranged in the reaction channel for the reaction gas to react, and an air outlet of the reaction channel is used to discharge gaseous products; the product analysis device comprises a multi-channel switching valve, an injection valve and a gas chromatograph, a plurality of reaction channels are provided, and are arranged in a one-to-one correspondence with the feed inlet of the multi-channel switching valve, and the air outlet of the reaction channel is connected to the corresponding feed inlet of the multi-channel switching valve, and the discharge port of the multi-channel switching valve is connected to the feed inlet of the gas chromatograph through the injection valve, the multi-channel switching valve can make the gas products of each reaction channel enter the gas chromatograph in sequence for analysis, and the injection valve can make the gas products of each reaction channel enter the gas chromatograph at a regular interval for analysis to evaluate the catalyst of each reaction channel.

[0007] Preferably, the multi-channel switching valve includes a multi-channel switching valve body, a first pneumatic pipeline and a first solenoid valve. A first pneumatic actuator is arranged in the multi-channel switching valve body, the first pneumatic pipeline is connected to the first pneumatic actuator, and the first solenoid valve is arranged on the first pneumatic pipeline.

[0008] Preferably, the injection valve includes an injection valve body, a second pneumatic pipeline and a second solenoid valve. A second pneumatic actuator is provided in the injection valve body. The second pneumatic pipeline is connected to the second pneumatic actuator. The second solenoid valve is provided on the second pneumatic pipeline.

[0009] Preferably, the reaction channel includes a mass flow controller, a fixed bed reactor and a cold trap connected in sequence, the air inlet of the mass flow controller is used to introduce the reaction gas, the fixed bed reactor is used to set the catalyst, and the fixed bed reactor is set in a heating furnace, the air outlet of the cold trap is used to discharge the gas product, and the liquid discharge port of the cold trap is used to discharge the liquid product.

[0010] Preferably, the fixed bed reactor includes a reaction tube, an air inlet sealing joint assembly and an air outlet sealing joint assembly, the air inlet end of the reaction tube can be connected to the air outlet of the mass flow controller through the air inlet sealing joint assembly, and is connected to a first thermocouple through the air inlet sealing joint assembly; the air outlet end of the reaction tube can be connected to the air inlet of the cold trap through the air outlet sealing joint assembly, and a catalyst carrier is arranged in the reaction tube.

[0011] Preferably, the air inlet sealing joint assembly includes a first sealing surface fastening tube, a second sealing surface fastening tube, a first pair of welded tubes, a first gas line tube, a tee joint, a second gas line tube, and a first reducer joint, which are sequentially connected, wherein the air inlet end of the reaction tube is inserted into the first end of the first sealing surface fastening tube and welded thereto; the second end of the first sealing surface fastening tube has a convex curved surface structure, and the first end of the second sealing surface fastening tube has a concave curved surface structure, and the second end of the first sealing surface fastening tube can be docked with the first end of the second sealing surface fastening tube and fixedly connected by a first curved surface fastening nut;

[0012] The first end of the first pair of welded pipes is inserted into the second end of the second sealing surface fastening pipe and welded to the second end; the second end of the first pair of welded pipes and the first end of the first gas pipe, the second end of the first gas pipe and the first end of the three-way joint, the second end of the three-way joint and the first end of the second gas pipe, and the second end of the second gas pipe and the first end of the first reducer conversion joint can all be sealed together; the second end of the first reducer conversion joint can be inserted into the first thermocouple and sealed to it; the third end of the three-way joint can be sealed to the gas outlet of the mass flow controller.

[0013] Preferably, the gas outlet sealing joint assembly includes a third sealing surface fastening tube, a fourth sealing surface fastening tube, a second pair of welded tubes, a third gas line tube and a second reducer conversion joint that are sequentially connected, wherein the gas outlet end of the reaction tube is inserted into the first end of the third sealing surface fastening tube and welded thereto; the second end of the third sealing surface fastening tube is a convex curved surface structure, the first end of the fourth sealing surface fastening tube is a concave curved surface structure, and the second end of the third sealing surface fastening tube can be docked with the first end of the fourth sealing surface fastening tube and fixedly connected by a second curved surface fastening nut;

[0014] The first end of the second pair of welded pipes is inserted into the second end of the fourth sealing surface fastening pipe and welded to it; the second end of the second pair of welded pipes and the first end of the third gas circuit pipe, as well as the second end of the third gas circuit pipe and the first end of the second reducer conversion joint can be sealed connected; the second end of the second reducer conversion joint can be sealed connected to the air inlet of the cold trap.

[0015] Preferably, the catalyst support is a lining mesh, and the lining mesh is fixed to the middle of the reaction tube.

[0016] Preferably, the heating furnace includes a furnace body and a fixed bracket, the furnace body is a cylindrical structure, the furnace chamber of the furnace body axially passes through the center of the furnace body, the fixed bed reactor can be clamped in the furnace chamber of the furnace body, and a heating layer and an insulation layer are sequentially arranged between the furnace chamber and the outer shell of the furnace body from the inside to the outside, a thermocouple channel is arranged in the insulation layer along the radial direction of the furnace body, and a second thermocouple is arranged in the thermocouple channel; the fixed bracket is supported on the bottom of the furnace body.

[0017] Preferably, the heating layer includes a front heating layer, a middle heating layer and a rear heating layer, the front heating layer is wrapped in the front section of the furnace chamber of the furnace body, the middle heating layer is wrapped in the middle section of the furnace chamber of the furnace body, and the rear heating layer is wrapped in the rear section of the furnace chamber of the furnace body; the front heating layer, the middle heating layer and the rear heating layer are all brick structures with heating resistance wires installed inside; the insulation layer is a quartz wool brick structure.

[0018] Compared with the related art, the present invention has achieved the following technical effects:

[0019] The fixed bed online reaction evaluation system provided by the present invention includes a fixed bed reaction device and a product analysis device, wherein the fixed bed reaction device includes multiple reaction channels, and the product analysis device includes a multi-channel switching valve, an injection valve and a gas chromatograph. When conducting a fixed bed online reaction evaluation experiment, a catalyst is placed in each reaction channel, and a reaction gas is introduced into each reaction channel to cause a reaction. The gas products of each reaction channel are sequentially entered into the gas chromatograph for analysis through the multi-channel switching valve, and the gas products of each reaction channel are periodically entered into the gas chromatograph for analysis through the injection valve, thereby evaluating the catalyst of each reaction channel, realizing fully automatic timed injection and analysis of multi-channel products, improving product analysis efficiency, reducing human operation errors compared to traditional manual injection and analysis, and improving data stability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A schematic diagram of a process flow of a fixed bed reaction apparatus provided in an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a multi-channel switching injection process provided by an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of a fixed bed reactor provided in an embodiment of the present invention;

[0024] Figure 4 for Figure 3 Enlarged view of the middle M part;

[0025] Figure 5 for Figure 4 Enlarged view of the middle N part;

[0026] Figure 6 A schematic diagram of the internal structure of a heating furnace provided in an embodiment of the present invention;

[0027] Figure 7 A schematic side view of a heating furnace provided in an embodiment of the present invention.

[0028] In the figure: 1-multi-channel switching valve, 2-injection valve, 3-mass flow controller, 4-fixed bed reactor, 401-reaction tube, 402-first thermocouple, 403-catalyst carrier, 404-first sealing surface fastening tube, 405-second sealing surface fastening tube, 406-first pair of welding tubes, 407-first gas line tube, 408-tee joint, 409-second gas line tube, 410-first reducer adapter, 411-first curved surface Fastening nut, 412-third sealing surface fastening tube, 413-fourth sealing surface fastening tube, 414-second pair of welding tubes, 415-third gas line tube, 416-second reducer conversion joint, 417-second curved surface fastening nut, 418-nut, 419-front ferrule, 420-rear ferrule, 5-cold trap, 6-heating furnace, 601-furnace body, 602-fixed bracket, 603-heating layer, 604-insulation layer, 605-second thermocouple. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The purpose of the present invention is to provide a fixed bed online reaction evaluation system to solve the problems existing in the related art and realize full-automatic timed sampling analysis of multi-channel products with high experimental efficiency and small error.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1-Figure 7As shown, this embodiment provides a fixed bed online reaction evaluation system, including a fixed bed reaction device and a product analysis device, the fixed bed reaction device includes a reaction channel, the air inlet of the reaction channel is used to introduce reaction gas, the reaction channel is used to set a catalyst for the reaction gas to react, and the air outlet of the reaction channel is used to discharge gas products; the product analysis device includes a multi-channel switching valve 1, an injection valve 2 and a gas chromatograph, there are multiple reaction channels, and they are arranged one-to-one corresponding to the feed port of the multi-channel switching valve 1, and the air outlet of the reaction channel is connected to the corresponding feed port of the multi-channel switching valve 1, and the outlet of the multi-channel switching valve 1 is connected to the feed port of the gas chromatograph through the injection valve 2, the multi-channel switching valve 1 can make the gas products of each reaction channel enter the gas chromatograph for analysis in turn, and the injection valve 2 can make the gas products of each reaction channel enter the gas chromatograph for analysis at a fixed time to evaluate the catalyst of each reaction channel, thereby realizing fully automatic timed injection and analysis of multi-channel products, high experimental efficiency and small error.

[0033] In this embodiment, the multi-channel switching valve 1 includes a multi-channel switching valve body, a first pneumatic pipeline and a first solenoid valve. A first pneumatic actuator is arranged in the multi-channel switching valve body, the first pneumatic pipeline is connected to the first pneumatic actuator, and the first solenoid valve is arranged on the first pneumatic pipeline. The first solenoid valve can control the compressed air flow in the first pneumatic pipeline, thereby controlling the multi-channel switching valve 1 to switch the feed channel. The channel switching frequency is: ≥2-3 times / s.

[0034] In this embodiment, the injection valve 2 includes an injection valve body, a second pneumatic pipeline and a second solenoid valve. A second pneumatic actuator is provided in the injection valve body, the second pneumatic pipeline is connected to the second pneumatic actuator, and the second solenoid valve is provided on the second pneumatic pipeline. The second solenoid valve can control the compressed air flow in the second pneumatic pipeline, thereby controlling the injection time of the injection valve 2, ensuring that the quantitative loop replacement time of the injection valve 2 is sufficient while enabling automatic injection; specifically, the injection valve 2 in this embodiment is preferably a six-way injection valve.

[0035] In this embodiment, the reaction channel includes a mass flow controller 3, a fixed bed reactor 4 and a cold trap 5 which are connected in sequence. The air inlet of the mass flow controller 3 is used to introduce the reaction gas, the fixed bed reactor 4 is used to set the catalyst, and the fixed bed reactor 4 is set in the heating furnace 6. The air outlet of the cold trap 5 is used to discharge the gas product, and the liquid discharge port of the cold trap 5 is used to discharge the liquid product.

[0036] Specifically, the fixed bed reaction device in this embodiment is as follows: Figure 1As shown, there are four reaction channels, and the air inlets of the four reaction channels come from an air inlet main pipe. The air inlet main pipe is provided with a filter and a main switch valve in sequence from front to back, and the air inlet end of the air inlet main pipe is connected to three air inlet branches, which can respectively introduce mixed gas, hydrogen and nitrogen. A pressure reducing valve, a ball valve and a one-way valve are provided on each air inlet branch in sequence from front to back. Among the four reaction channels in this embodiment, Figure 1 The reaction channel where the two fixed bed reactors 4 are located on the left side of the middle is described. The outlet of the fixed bed reactor 4 on the upper left is connected to the inlet of the fixed bed reactor 4 on the lower left through a connecting pipeline. The connecting pipeline is provided with a filter, a pressure transmitter and a high-temperature back-pressure valve from front to back. The outlet pipeline of the fixed bed reactor 4 on the upper left is connected between the filter and the high-temperature back-pressure valve of the connecting pipeline. Figure 1 The connection mode of the reaction channels where the two fixed bed reactors 4 are located on the right side is similar, and Figure 1 A ball valve is provided on each outlet pipe of the fixed bed reactor 4 on the upper left and upper right sides of the middle. Figure 1 A ball valve is provided on each inlet pipe of the fixed bed reactor 4 at the lower left and lower right in the middle. With this piping method, two operating states of the device can be realized by switching the corresponding valves: one is that the four fixed bed reactors 4 operate separately, and the other is that the upper and lower fixed bed reactors 4 on the same side operate in series; ball valves are provided before and after the mass flow controller 3 in this embodiment, and a bypass is connected between the two corresponding ball valves to facilitate the switching out of the mass flow controller 3, and pressure gauges are provided before and after the mass flow controller 3; a first thermocouple 402 is provided in the fixed bed reactor 4 of each reaction channel in this embodiment, and three second thermocouples 605 are provided in the corresponding heating furnace 6; a filter, a pressure transmitter and a pressure gauge, a back pressure valve, a temperature transmitter and a temperature gauge are provided on the outlet pipe of the cold trap 5 in this embodiment from front to back, and a needle valve and a ball valve are provided on the discharge pipe of the cold trap 5 from front to back; the four reaction channels in this embodiment correspond to Figure 2 Feed ports 1 to 4 of the middle multi-channel switching valve 1 can realize the evaluation of four catalysts, greatly improving the experimental efficiency.

[0037] It should be noted that the fixed bed reaction device of the present application is mainly composed of air intake, reaction, analysis and control systems; the air intake system mainly uses a mass flow controller 3 to control the mixing and flow of gases; the reaction system is mainly composed of a fixed bed reactor 4 and a heating furnace 6, which provides the high-pressure and high-temperature environment required for the reaction site; the solenoid valve + multi-channel switching valve 1 is used to realize the switching of the gases after the reaction of the four channels, ensuring that the gases of the four channels enter the gas chromatograph in sequence. In addition, the analysis system uses a combination of solenoid valve + injection valve 2 to regularly send the product into the gas chromatograph for analysis and data recording; the control system includes temperature, pressure, and flow monitoring sites and a signal feedback system, combined with a human-machine interface remote control module and a programmed operation module to realize automated and programmed operation.

[0038] The operating process of the entire device is as follows: the reaction gas flows into the mass flow controller 3 after the inlet pressure is controlled by the pressure reducing valve; after flow control, the reaction gas enters the reaction system, and the temperature is controlled by the heating furnace 6; after the reaction, the gas flows through the cold trap 5 to achieve gas-liquid phase separation, and the liquid product can be collected by the bypass. The gas product continues to flow through the back pressure valve (the pressure control element of the entire system) and then enters the gas chromatograph through the multi-channel switching valve 1 and the injection valve 2; the final product composition is automatically analyzed and calculated by the gas chromatograph and the data is stored; the maximum operating temperature of the entire device is: 1000℃, the maximum pressure: 10MPa, the temperature accuracy: ±0.5℃, the pressure accuracy: ±0.05MPa, the flow accuracy: ±0.1mL / min, and the experimental parallel error: ±5%.

[0039] In this embodiment, if Figure 3-Figure 5 As shown, the fixed bed reactor 4 includes a reaction tube 401, an air inlet sealing joint assembly and an air outlet sealing joint assembly. The air inlet end of the reaction tube 401 can be connected to the air outlet of the mass flow controller 3 through the air inlet sealing joint assembly, and is connected to a first thermocouple 402 through the air inlet sealing joint assembly; the air outlet end of the reaction tube 401 can be connected to the air inlet of the cold trap 5 through the air outlet sealing joint assembly, and a catalyst carrier 403 is arranged in the reaction tube 401; specifically, the reaction tube 401 in this embodiment is preferably a stainless steel tube, and the catalyst carrier 403 is preferably a lining mesh, which is fixed to the middle of the reaction tube 401.

[0040] In this embodiment, the air intake sealing joint assembly includes a first sealing surface fastening tube 404, a second sealing surface fastening tube 405, a first pair of welding tubes 406, a first gas line tube 407, a three-way joint 408, a second gas line tube 409 and a first reducer conversion joint 410, which are connected in sequence, wherein the air intake end of the reaction tube 401 is inserted into the first end of the first sealing surface fastening tube 404 and welded thereto; the second end of the first sealing surface fastening tube 404 is a convex curved surface structure, the first end of the second sealing surface fastening tube 405 is a concave curved surface structure, and the second end of the first sealing surface fastening tube 404 can be docked with the first end of the second sealing surface fastening tube 405, and fixedly connected by a first curved surface fastening nut 411, so that the two curved surface fasteners are squeezed and deformed under the action of the first curved surface fastening nut 411, thereby achieving a sealing effect.

[0041] In this embodiment, the first end of the first pair of welded tubes 406 is inserted into the second end of the second sealing surface fastening tube 405 and welded thereto; the second end of the first pair of welded tubes 406 and the first end of the first gas line tube 407, the second end of the first gas line tube 407 and the first end of the tee joint 408, the second end of the tee joint 408 and the first end of the second gas line tube 409, and the second end of the second gas line tube 409 and the first end of the first reducer 410 can all be sealedly connected; the second end of the first reducer 410 can be inserted into the first thermocouple 402 and sealed therewith; the third end of the tee joint 408 can be sealedly connected to the gas outlet of the mass flow controller 3, that is, the function of the tee joint 408 is to fix the first gas line tube 407 to ensure the entry of gas while the first thermocouple 402 can be inserted, and the first thermocouple 402 is connected and sealed using a reducer.

[0042] In this embodiment, the gas outlet sealing joint assembly includes a third sealing surface fastening tube 412, a fourth sealing surface fastening tube 413, a second pair of welding tubes 414, a third gas path tube 415 and a second reducer conversion joint 416 that are connected in sequence, wherein the gas outlet end of the reaction tube 401 is inserted into the first end of the third sealing surface fastening tube 412 and welded to it; the second end of the third sealing surface fastening tube 412 is a convex curved surface structure, the first end of the fourth sealing surface fastening tube 413 is a concave curved surface structure, and the second end of the third sealing surface fastening tube 412 can be docked with the first end of the fourth sealing surface fastening tube 413, and fixedly connected by the second curved surface fastening nut 417, so that the two curved surface fasteners are squeezed and deformed under the action of the second curved surface fastening nut 417, thereby achieving a sealing effect.

[0043] In this embodiment, the first end of the second pair of welded tubes 414 is inserted into the second end of the fourth sealing surface fastening tube 413 and welded thereto; the second end of the second pair of welded tubes 414 and the first end of the third gas line tube 415, as well as the second end of the third gas line tube 415 and the first end of the second reducer joint 416 can be sealedly connected; the second end of the second reducer joint 416 can be sealedly connected to the air inlet of the cold trap 5.

[0044] Specifically, in this embodiment, the second end of the first pair of welded pipes 406 and the first end of the first air pipe 407, the second end of the first air pipe 407 and the first end of the tee joint 408, the second end of the tee joint 408 and the first end of the second air pipe 409, the second end of the second air pipe 409 and the first end of the first reducer 410, the second end of the second pair of welded pipes 414 and the first end of the third air pipe 415, and the second end of the third air pipe 415 and the first end of the second reducer 416 are all sealed and connected using nuts 418, front ferrules 419 and rear ferrules 420.

[0045] Compared with the traditional flange sealing method, there are problems such as large reaction tube joints, complicated operation, and poor sealing. The present application has made innovations in the reaction tube: the flange is replaced by a threaded sealing method, which greatly reduces the joint volume; due to the fixed characteristics of the flange, multiple screws are required for fixing during the sealing process, which is time-consuming and labor-intensive. However, the present application utilizes a threaded fastening sealing method to simplify the operation and improve the sealing effect. Compared with the traditional sealing process that requires the use of sealing gaskets, the present application has an innovatively designed hyperbolic contact surface that utilizes slight deformation of the contact surface to produce a sealing effect. At the same time, the introduction of a hard curved surface eliminates the need for a sealing gasket, avoiding problems such as poor sealing effect caused by gasket misalignment.

[0046] In this embodiment, if Figure 6-Figure 7 As shown, the heating furnace 6 includes a furnace body 601 and a fixed bracket 602. The furnace body 601 is a cylindrical structure. The furnace chamber of the furnace body 601 axially passes through the center of the furnace body 601. The fixed bed reactor 4 can be snapped into the furnace chamber of the furnace body 601, and a heating layer 603 and an insulation layer 604 are sequentially arranged between the furnace chamber and the outer shell of the furnace body 601 from the inside to the outside. A thermocouple channel is arranged in the insulation layer 604 along the radial direction of the furnace body 601, and a second thermocouple 605 is arranged in the thermocouple channel; the fixed bracket 602 is supported at the bottom of the furnace body 601.

[0047] Furthermore, the heating layer 603 includes a front heating layer, a middle heating layer and a rear heating layer. The front heating layer is wrapped around the front section of the furnace chamber of the furnace body 601, the middle heating layer is wrapped around the middle section of the furnace chamber of the furnace body 601, and the rear heating layer is wrapped around the rear section of the furnace chamber of the furnace body 601; the front heating layer, the middle heating layer and the rear heating layer are all brick structures with heating resistance wires installed inside; the insulation layer 604 is a quartz wool brick structure.

[0048] Specifically, the thermocouple channel in this embodiment is fixed to the heating furnace 6 by welding, and a ferrule interface is provided for fixing the second thermocouple 605; three second thermocouples 605 are provided, and accordingly, three thermocouple channels are also provided, and the three second thermocouples 605 are respectively located in the front heating layer, the middle heating layer and the rear heating layer; the fixed bracket 602 is connected to the furnace body 601 by welding, and is provided with bolt fixing holes for easy fixation to the aluminum alloy frame; the heating resistance wire is buried in the heating brick, and the reaction tube 401 is heated by heat conduction through the heating brick; the insulation brick is located on the outside of the heating brick and is composed of quartz wool, which can reduce the heat conduction and heat radiation effects in the center of the heating furnace 6.

[0049] It should be noted that the heating furnace 6 in this embodiment adopts a three-stage heating structure. The three-stage heating furnace 6 uses three heating wires to heat the upper, middle and lower sections of the furnace, which can control the temperature of different areas of the furnace.

[0050] A traditional single-stage heating furnace has only one heating wire, which will result in a high temperature in the middle of the furnace and low temperatures at both ends, which also leads to a very small constant temperature zone in the middle of the furnace. The three-stage heating separates the heating, which can appropriately increase the heating temperature at both ends, ensuring that the temperature at both ends will not be significantly lower than the middle of the furnace, thus ensuring a large constant temperature zone in the middle of the furnace.

[0051] The biggest advantage of this structure is that it has a smaller volume (350mm in length, referring to the length of the entire heating furnace 6) and a larger constant temperature zone (50mm, referring to the length of the constant temperature zone in the middle of the furnace, that is, the area extending 25mm from the middle of the furnace to both ends, with a constant temperature), and the temperature difference between the two ends and the center of the heating furnace 6 is less than 5°C, ensuring that the temperature of the entire reaction system is constant; three K-type thermocouples are used to monitor and feedback the temperature in real time to ensure the stability of the furnace temperature; the heating furnace 6 is easy to operate, with three thermocouple jacks and a fixed bracket 602 on the back, which makes rational use of space design and reduces the footprint of the device; the furnace adopts a design with small ends and large middle, and the small part is used to clamp the reaction tube 401 to form a fixing effect and take into account the insulation effect; the heating bricks in the middle transfer heat to the reaction tube 401 for temperature control; the overall split-type design allows the furnace to be completely opened, which is convenient for loading and unloading of the reaction tube 401 and subsequent maintenance of the furnace.

[0052] The usage process of the fixed bed online reaction evaluation system provided in this embodiment is as follows:

[0053] Experimental conditions: catalyst is NJT-5, reaction temperature is 400℃, feed gas H2 / CO2 ratio is 3, pressure is 3MPa, space velocity is 900, 1500, 2100ml / (g cat .h).

[0054] First, the NJT-5 catalyst was loaded into the reaction tube 401. After loading, the system pressure was controlled to the reaction pressure using a back-pressure valve, and the air tightness of the device was tested. After the air tightness test was completed, the back-pressure valve was opened to normal pressure, the gas source was switched to pure H2, and the H2 flow rate was controlled to a constant value using a mass flow controller 3. The heating furnace 6 was then slowly heated to 450°C, and the NJT-5 catalyst was reduced at this temperature for 4 hours. The temperature was then lowered to the reaction temperature of 400°C. The H2 gas cylinder was closed, and after the remaining H2 in the device was exhausted, the back-pressure valve was adjusted to the reaction pressure, the raw gas line was connected, and the flowmeter parameters were set to the specified flow rate. After waiting for 15 minutes for stable bubbling in the tail pipe and no obvious pressure fluctuations, product analysis was performed.

[0055] The obtained product distribution is listed in the table below. It can be seen from Table 1 that:

[0056] The air velocity is 900ml / (g cat .h), X CO2 44%, S CO 17.4%, S CH4 12.6%, S(C2-C4 ＝ ) is 23.1%, S(C2-C4 0 ) is 7.3%, S C5+ It is 39.6%.

[0057] As the airspeed increases, X CO2 、S(C2-C4 0 ), S C5+ Gradually decrease, S CO Significantly increased.

[0058] When the air velocity is 2100ml / (g cat .h), X CO2 40%, S CO 23%, S CH4 13.7%, S(C2-C4 ＝ ) is 21.7%, S(C2-C4 0 ) is 5.6%, S C5+ It is 36%.

[0059] It can be seen that this system can carry out CO2 catalytic hydrogenation evaluation experiments at different space velocities.

[0060] Table 1

[0061]

[0062] In summary, this system has the following advantages:

[0063] First, reaction system: research and development of a small threaded curved surface hard-sealed reactor with easy operation, excellent sealing and resistance to high temperature and high pressure; in response to the problems of large size, poor sealing and complicated operation of the reaction system of the existing fixed bed reactor on the market, this application innovatively developed a small threaded curved surface hard-sealed joint to replace the traditional flange joint. Compared with the flange joint, the curved surface joint design takes into account the small size while having excellent sealing ability, and the threaded design makes loading and unloading easier, greatly saving the operating cost and time cost of the device.

[0064] Second, the analysis system: construct a compact multi-channel evaluation system with independent air intake and timed switching, and set up a high-sensitivity and stable online analysis system with precise timed automatic sampling function; in view of the problems of complex operation and large analysis data errors in the existing fixed-bed reaction device analysis system on the market, this application adopts a combination of solenoid valve + multi-channel switching valve 1 + injection valve 2, which can realize multi-channel fully automatic timed switching injection analysis; the solenoid valve is used to control the operation of the multi-channel switching valve 1 to realize free switching between multiple channels, thereby improving the product analysis efficiency. In addition, the solenoid valve is used to control the automatic sampling and analysis of the injection valve 2, which greatly reduces the errors caused by human operation compared with the traditional manual injection analysis, and improves the data stability of the equipment.

[0065] Third, control system: research and develop a micro automatic pressure regulating controller with high precision and wide pressure range; develop an intelligent human-computer interaction parameter control interface that integrates centralized display, real-time storage and fast and accurate feedback signal functions; build a remote real-time monitoring platform with rapid response and no geographical restrictions; in response to the problems of decentralized control systems and low intelligence of existing fixed-bed reaction devices on the market, this application utilizes the process of underlying signal collection, mid-end instrument conversion and feedback, and terminal data display and input to achieve real-time monitoring of experimental parameters such as device temperature, pressure and flow. In addition, the human-computer interface of this application is connected to a remote monitoring function and a programmed operation module without geographical restrictions. Compared with traditional fixed-bed reaction equipment that requires manual real-time supervision and operation, this system has a higher degree of automation and intelligence.

[0066] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A fixed bed online reaction evaluation system, characterized by: It includes a fixed bed reaction device and a product analysis device, the fixed bed reaction device includes a reaction channel, the air inlet of the reaction channel is used to introduce reaction gas, the reaction channel is used to set a catalyst for the reaction gas to react, and the air outlet of the reaction channel is used to discharge gaseous products; the product analysis device includes a multi-channel switching valve, an injection valve and a gas chromatograph, there are multiple reaction channels, and they are arranged one-to-one corresponding to the feed ports of the multi-channel switching valve, and the air outlet of the reaction channel is connected to the corresponding feed port of the multi-channel switching valve, the outlet of the multi-channel switching valve is connected to the feed port of the gas chromatograph through the injection valve, the multi-channel switching valve can make the gas products of each reaction channel enter the gas chromatograph for analysis in turn, and the injection valve can make the gas products of each reaction channel enter the gas chromatograph for analysis at a regular interval to evaluate the catalyst of each reaction channel.

2. The fixed bed online reaction evaluation system according to claim 1, characterized in that: The multi-channel switching valve includes a multi-channel switching valve body, a first pneumatic pipeline and a first solenoid valve. A first pneumatic actuator is arranged in the multi-channel switching valve body, the first pneumatic pipeline is connected to the first pneumatic actuator, and the first solenoid valve is arranged on the first pneumatic pipeline.

3. The fixed bed online reaction evaluation system according to claim 1, characterized in that: The injection valve includes an injection valve body, a second pneumatic pipeline and a second solenoid valve. A second pneumatic actuator is provided in the injection valve body. The second pneumatic pipeline is connected to the second pneumatic actuator. The second solenoid valve is provided on the second pneumatic pipeline.

4. The fixed bed online reaction evaluation system according to claim 1, characterized in that: The reaction channel includes a mass flow controller, a fixed bed reactor and a cold trap connected in sequence. The air inlet of the mass flow controller is used to introduce the reaction gas. The catalyst is arranged in the fixed bed reactor, and the fixed bed reactor is arranged in a heating furnace. The air outlet of the cold trap is used to discharge the gas product, and the liquid discharge port of the cold trap is used to discharge the liquid product.

5. The fixed bed online reaction evaluation system according to claim 4, characterized in that: The fixed bed reactor includes a reaction tube, an air inlet sealing joint assembly and an air outlet sealing joint assembly. The air inlet end of the reaction tube can be connected to the air outlet of the mass flow controller through the air inlet sealing joint assembly, and is connected to a first thermocouple through the air inlet sealing joint assembly; the air outlet end of the reaction tube can be connected to the air inlet of the cold trap through the air outlet sealing joint assembly, and a catalyst carrier is arranged in the reaction tube.

6. The fixed bed online reaction evaluation system according to claim 5, characterized in that: The air inlet sealing joint assembly includes a first sealing surface fastening tube, a second sealing surface fastening tube, a first pair of welded tubes, a first gas line tube, a tee joint, a second gas line tube, and a first reducer joint, which are sequentially connected, wherein the air inlet end of the reaction tube is inserted into the first end of the first sealing surface fastening tube and welded thereto; the second end of the first sealing surface fastening tube has a convex curved surface structure, and the first end of the second sealing surface fastening tube has a concave curved surface structure, and the second end of the first sealing surface fastening tube can be docked with the first end of the second sealing surface fastening tube and fixedly connected by a first curved surface fastening nut; The first end of the first pair of welded pipes is inserted into the second end of the second sealing surface fastening pipe and welded to the second end; the second end of the first pair of welded pipes and the first end of the first gas pipe, the second end of the first gas pipe and the first end of the three-way joint, the second end of the three-way joint and the first end of the second gas pipe, and the second end of the second gas pipe and the first end of the first reducer conversion joint can all be sealed together; the second end of the first reducer conversion joint can be inserted into the first thermocouple and sealed to it; the third end of the three-way joint can be sealed to the gas outlet of the mass flow controller.

7. The fixed bed online reaction evaluation system according to claim 5, characterized in that: The gas outlet sealing joint assembly includes a third sealing surface fastening tube, a fourth sealing surface fastening tube, a second pair of welded tubes, a third gas line tube, and a second reducer conversion joint that are sequentially connected, wherein the gas outlet end of the reaction tube is inserted into the first end of the third sealing surface fastening tube and welded thereto; the second end of the third sealing surface fastening tube is a convex curved surface structure, the first end of the fourth sealing surface fastening tube is a concave curved surface structure, and the second end of the third sealing surface fastening tube can be docked with the first end of the fourth sealing surface fastening tube and fixedly connected by a second curved surface fastening nut; The first end of the second pair of welded pipes is inserted into the second end of the fourth sealing surface fastening pipe and welded to it; the second end of the second pair of welded pipes and the first end of the third gas circuit pipe, as well as the second end of the third gas circuit pipe and the first end of the second reducer conversion joint can be sealed connected; the second end of the second reducer conversion joint can be sealed connected to the air inlet of the cold trap.

8. The fixed bed online reaction evaluation system according to claim 5, characterized in that: The catalyst supporting member is a lining mesh, and the lining mesh is fixed to the middle of the reaction tube.

9. The fixed bed online reaction evaluation system according to claim 4, characterized in that: The heating furnace includes a furnace body and a fixed bracket. The furnace body is a cylindrical structure. The furnace chamber of the furnace body axially penetrates the center of the furnace body. The fixed bed reactor can be clamped in the furnace chamber of the furnace body. A heating layer and an insulation layer are sequentially arranged from the inside to the outside between the furnace chamber and the outer shell of the furnace body. A thermocouple channel is arranged in the insulation layer along the radial direction of the furnace body, and a second thermocouple is arranged in the thermocouple channel. The fixed bracket is supported on the bottom of the furnace body.

10. The fixed bed online reaction evaluation system according to claim 9, characterized in that: The heating layer includes a front heating layer, a middle heating layer and a rear heating layer. The front heating layer is wrapped around the front section of the furnace chamber of the furnace body, the middle heating layer is wrapped around the middle section of the furnace chamber of the furnace body, and the rear heating layer is wrapped around the rear section of the furnace chamber of the furnace body. The front heating layer, the middle heating layer and the rear heating layer are all brick structures with heating resistance wires inside. The insulation layer is a quartz wool brick structure.

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