A delivery system and method for a low temperature fischer-tropsch synthesis catalyst

Abstract

The application discloses a low-temperature Fischer-Tropsch synthesis catalyst conveying system and a conveying method, which comprise a catalyst tank truck, a gas storage tank, a first gas charging pipeline, a second gas charging pipeline, a third gas charging pipeline, a fourth gas charging pipeline and a catalyst storage tank; wherein the catalyst tank truck and the catalyst storage tank are connected through a conveying main pipe; one end of each of the four gas charging pipelines is connected with the gas storage tank; the first gas charging pipeline is connected with the catalyst tank truck; the second gas charging pipeline, the third gas charging pipeline and the fourth gas charging pipeline are connected with the end, 1 / 3-1 / 2 and 1 / 2-2 / 3 of the conveying main pipe respectively as air supplement pipelines.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of Fischer-Tropsch synthesis catalyst conveying system and method, and particularly relates to a low-temperature Fischer-Tropsch synthesis catalyst conveying system and method. BACKGROUND

[0002] The statements herein are provided only to complement the background of the present application and are not necessarily indicative of the prior art.

[0003] The low-temperature Fischer-Tropsch synthesis catalyst is extremely crucial in production, and the catalyst is prepared by using a precipitation filter cake to pass through spray drying and calcination to obtain a microspherical Fischer-Tropsch synthesis iron-based catalyst. The catalyst has a porous spherical structure and a very large specific surface area, and its structural properties determine that it is easy to break. Traditional conveying methods include pneumatic conveying and mechanical transmission conveying, and these methods have problems such as complex operation, easy blockage, inability to automatically convey, and high breakage rate. The traditional conveying device needs a gas pump device and cannot be directly conveyed from a tank truck to a charging groove, and multiple transfers increase the breakage rate of the Fischer-Tropsch synthesis catalyst. After the catalyst is broken, the selectivity changes, the yield of the target product decreases, and the catalyst fine powder cannot be effectively removed in the reactor slurry. The built-in filter element of the reactor will soon be clogged and fail, the particle size distribution of the catalyst gradually deteriorates, the reaction activity decreases, the bed level control is disordered, and the stable operation of the Fischer-Tropsch synthesis slurry bed reaction is seriously affected. Therefore, a new catalyst conveying device and method are needed to improve the conveying efficiency, reduce the breakage rate, reduce the operation difficulty, and directly convey the tank truck. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a low-temperature Fischer-Tropsch synthesis catalyst conveying system and method.

[0005] In order to achieve the above-mentioned purpose, the present application is realized by the following technical solutions:

[0006] In the first aspect, the present application provides a low-temperature Fischer-Tropsch synthesis catalyst conveying system, which comprises a catalyst tank truck, a gas storage tank, a first gas charging pipeline, a second gas charging pipeline, a third gas charging pipeline, a fourth gas charging pipeline, and a catalyst storage tank.

[0007] The catalyst tank truck and the catalyst storage tank are connected through a conveying main pipe; one end of each of the four gas charging pipelines is connected with the gas storage tank.

[0008] The first gas charging pipeline is connected with the catalyst tank truck.

[0009] The second air charging pipeline is in communication with the end of the conveying main pipe, and comprises a main air charging pipeline and a cutting branch pipe assembly, the cutting branch pipe assembly is arranged in a circumferential direction around the conveying main pipe, each cutting branch pipe is in communication with the main air charging pipeline and the conveying main pipe, and the cutting branch pipe assembly intermittently charges air into the conveying main pipe, so as to cut the catalyst powder column and form an alternating structure of the catalyst powder column and the air column.

[0010] The third air charging pipeline and the fourth air charging pipeline are used as air supplement pipelines and are connected with the conveying main pipe at different lengths.

[0011] The first air charging pipeline is connected with the catalyst tank truck, is used for adjusting the initial speed of catalyst conveying, controls the catalyst conveying speed, and reduces the breakage rate, the speed of the catalyst in the pipeline is calculated according to the air charging pressure and the pipe diameter of the conveying pipeline, the second air charging pipeline is in a ring hole structure, 4-6 Φ6 small holes are arranged on the pipeline in one circle, air enters the pipeline through the small holes to divide the catalyst into powder columns, the pressure of the second air charging pipeline is set to be 0.1-0.3 MPa higher than the pressure of the tank truck, the air inlet is arranged on the vertical pipeline, the large pressure and the multi-surface air inlet ensure the effective cutting of the catalyst powder, the length of the catalyst powder column and the length of the interval air column are controlled by the opening and closing time and the interval time of the air charging valve, the conveying pipeline forms a state that a powder column and an air column are alternately arranged at intervals, instead of a fluidized and suspended state, the breakage caused by the collision between the catalysts is reduced, the powder column is relatively dense, the air supplement forms an air film between the powder column and the pipeline, and the contact wear between the catalyst and the pipeline is further reduced, and the possibility of catalyst breakage is reduced.

[0012] In addition, because the catalyst is divided into powder columns, the catalyst conveying is actually from a powder column to an air column, and therefore, a very small pressure difference is required, the conveying pressure is controlled to be very low, the front end speed is very small, and the breakage rate of the catalyst is greatly reduced. After conveying for a distance, the air column is diffused and lost, the third and fourth holes are arranged at the bottom of the pipeline, are controlled to be opened when the air column passes according to the parameters of the front end, air is supplemented, the air supplement amount is greatly reduced compared with the first valve, the supplement time is set according to the pipe diameter and the particle size of the catalyst, and the whole conveying process is ensured to be continuous and stable.

[0013] In some embodiments, the number of cutting branch pipes is 4-10.

[0014] In some embodiments, the first air charging pipeline comprises a main air inlet pipeline and a loose branch pipe assembly, the main air inlet pipeline is in communication with the top of the tank truck, the loose branch pipe assembly is distributed at different heights in the tank truck and is connected with an air source, and a through hole is arranged on each loose branch pipe.

[0015] In order to prevent the catalyst from being compacted in the tank truck and unable to be transported, 4-6 loosening air pipes are arranged in the air charging pipe in addition to the main air charging pipe, the pipe diameter of the loosening air pipe is small and small holes are arranged in the pipe, so that the catalyst is loosened but not in a fluidized state, and the loosened catalyst is transported outward through the delivery main pipe under the air pressure at the top.

[0016] In some embodiments, a pressure reducing valve and an air valve are arranged on each of the four air charging pipes.

[0017] Preferably, a pressure gauge is arranged downstream of the pressure reducing valve on the second air charging pipe, the third air charging pipe and the fourth air charging pipe. The pressure of the reduced gas is detected to ensure good pneumatic conveying effect.

[0018] In some embodiments, a material level meter and a pressure gauge are arranged in the catalyst tank truck.

[0019] In some embodiments, a dust removal device is further included, the dust removal device is connected to the top of the catalyst storage tank, and a catalyst collecting tank is connected to the lower end of the dust removal device. The catalyst dust overflowing from the top of the catalyst storage tank is recycled by using the dust removal device.

[0020] In some embodiments, a control system is further included, the control system is connected to each pressure gauge, air valve and pressure reducing valve.

[0021] In the second aspect, the application provides a method for transporting low-temperature Fischer-Tropsch synthesis catalyst, which comprises the following steps:

[0022] The catalyst tank truck is charged to 0.1-0.5 MPaG, and loosening air is introduced into the tank truck through the loosening pipe at the same time, so that the catalyst powder is transported outward through the delivery main pipe under the air pressure;

[0023] The second air charging pipe intermittently ventilates the delivery main pipe, so as to cut the catalyst powder column in the delivery main pipe and form a delivery form in which the air column and the catalyst powder column are alternately arranged, and the catalyst powder column is transported forward under the air pressure;

[0024] The third air charging pipe and the fourth air charging pipe supplement air into the air column when the air column passes;

[0025] The catalyst is pneumatically transported, and the dust removal device is automatically operated;

[0026] When the material level in the catalyst tank truck is lower than the set material level, the air valve is automatically closed and the transportation is stopped.

[0027] The beneficial effects achieved by one or more embodiments of the application are as follows:

[0028] 1. High efficiency: the application can realize stable transportation of low-temperature Fischer-Tropsch synthesis catalyst, realize unattended operation, reduce the workload of manual addition and improve the efficiency.

[0029] 2. Safe and reliable: the application adopts an automatic control system, which can timely discover and handle abnormal conditions to ensure safe and reliable operation of the system.

[0030] 3. Low breakage rate: the application can control the breakage rate of the low-temperature Fischer-Tropsch synthesis catalyst during the conveying process within 5 ‰.

[0031] 4. Simple process: the application does not need a warehouse pump that is a standard configuration for powder conveying, and does not need to set a foundation pit, which greatly reduces the engineering quantity, investment, and land use, and keeps the site clean.

[0032] 5. Environmental protection and energy saving: the application can reduce catalyst waste, reduce production costs, and reduce environmental pollution.

[0033] Actual application effect: through actual application test, the low-temperature Fischer-Tropsch synthesis catalyst conveying system of the application has the characteristics of high efficiency, safety, reliability, simplicity, and low breakage rate, and can meet the needs of low-temperature Fischer-Tropsch synthesis catalyst conveying. BRIEF DESCRIPTION OF DRAWINGS

[0034] The drawings accompanying the specification of the application form a part of the application and serve to further provide a further understanding of the application, the illustrative embodiments of the application and their description serve to explain the application without constituting an improper limitation thereof.

[0035] Figure 1 is a structural schematic diagram of the low-temperature Fischer-Tropsch synthesis catalyst conveying system of the embodiment of the application;

[0036] Figure 2 is a schematic diagram of the internal pipeline distribution of the tank car in the embodiment of the application;

[0037] Figure 3 is a structural schematic diagram of the second air charging pipeline in the embodiment of the application;

[0038] Figure 4 is a sectional view structural schematic diagram of the second air charging pipeline in the embodiment of the application.

[0039] Among them, 1 is a level meter; 2 is a catalyst tank car; 3 is a gas storage tank; 4 is a pressure gauge; 5 is a valve; 6 is a pneumatic valve; 7 is a pressure gauge; 8 is a pressure reducing valve; 9 is a pneumatic valve; 10 is a pressure gauge; 11 is a pressure reducing valve; 12 is a pressure reducing valve; 13 is a pressure gauge; 14 is a pneumatic valve; 15 is a catalyst storage tank; 16 is a catalyst collection tank; 17 is a dust removal device; 18 is a pressure reducing valve; 19 is a pneumatic valve; 20 is a pressure gauge; 21 is a pneumatic valve; 22 is a flexible connection; 23 is a first air charging pipeline; 24 is a main air inlet pipeline; 25 is a tank car; 26 is a loosening branch pipe; 27 is a conveying main pipe; 28 is a cutting branch pipe; and 29 is a second air charging pipeline. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] The present invention will be further described below with reference to the embodiments.

[0042] Example

[0043] like Figure 1 As shown, a low-temperature iron-based Fischer-Tropsch synthesis catalyst conveying system mainly includes a catalyst transport tanker 2, which is a pressure tanker with a design pressure of 0.5~1 MPaG. The tanker is equipped with a level gauge 1 and a pressure detection device 20. A flexible connection 22 connects the tanker to the conveying pipeline for quick connection. A manual valve 5 and a pneumatic valve 21 are installed on the catalyst conveying pipeline for timely shut-off to ensure safety. The tanker is equipped with a pressurization pipeline, and four gas filling pipelines are installed at the outlet of the gas storage tank 3. A pressure detection device 4 is installed on the gas storage tank to detect the pressure of the gas storage tank and ensure sufficient conveying power. One gas filling pipeline is connected to the catalyst tanker and is equipped with a pressure reducing valve 18 to control the conveying speed by adjusting the tanker pressure. A pneumatic valve 19 is used to adjust the tanker pressure to ensure stable tanker pressure during the conveying process. The second gas filling pipeline is located after the pneumatic valve 21 and is equipped with a pressure reducing valve 8 to control the replenishment pressure. A pressure detector 7 detects the pressure after the pressure reducing valve, and a pneumatic valve 6 is used to control the replenishment time and interval. The third gas supply pipeline is located at 1 / 3 to 1 / 2 of the pipeline, equipped with a pressure reducing valve 11 to control the gas supply pressure, a pressure sensor 10 to detect the pressure after the pressure reducing valve, and a pneumatic valve 9 to control the gas supply time and interval. The fourth gas supply pipeline is located at 1 / 1 to 2 / 3 of the pipeline, equipped with a pressure reducing valve 12 to control the gas supply pressure, a pressure sensor 13 to detect the pressure after the pressure reducing valve, and a pneumatic valve 14 to control the gas supply time and interval. The catalyst storage tank 15 receives the delivered catalyst, and a bag filter dust collector 17 is installed on top. The recovered catalyst is intermittently purged into the catalyst collection tank 16.

[0044] The second gas filling pipe connects to the end of the main delivery pipe and includes a main gas filling pipe and a cutting branch pipe assembly. The cutting branch pipe assembly is arranged circumferentially around the main delivery pipe. Each cutting branch pipe connects the main gas filling pipe and the main delivery pipe. The cutting branch pipe assembly intermittently supplies gas into the main delivery pipe to cut the catalyst powder columns, forming an alternating structure of catalyst powder columns and gas columns. The number of cutting branch pipes is 4-10. The second gas filling pipe has an annular hole structure (e.g., Figure 3 and Figure 4As shown in the figure, 4-6 Φ6 small holes are opened around the pipeline, and the gas enters the pipeline through the small holes to divide the catalyst into a section of powder column, the second air charging pipeline is set to be 0.1-0.3 MPa higher than the tank car pressure, and the air inlet is arranged on the vertical pipeline, so that the effective cutting of the catalyst powder is ensured by the large pressure and multi-surface air inlet, and the length of the catalyst powder column and the length of the interval gas column are controlled by the opening and closing time and the interval time of the air charging valve, so that the state of the interval setting of the powder column and the air column is formed in the conveying pipeline instead of the state of the fluidized suspension, and the breakage caused by the collision between the catalysts is reduced.

[0045] As shown in the figure, Figure 2 The first air charging pipeline includes a main air inlet pipeline and a loose branch pipeline assembly, the main air inlet pipeline is communicated with the top of the tank car, the loose branch pipeline assembly is distributed at different heights in the tank car and is connected with the gas source, and a through hole is arranged on each loose branch pipeline. The loose air pipe has a small diameter and is provided with small holes, so that the catalyst is loosened but not in a fluidized state, and the loosened catalyst is conveyed outward through the conveying main pipe under the air pressure at the top.

[0046] The application also provides a low-temperature iron-based Fischer-Tropsch synthesis catalyst conveying method, which comprises the following steps:

[0047] Step one, connect the flexible connection 22 with the catalyst tank car 2, and open the valve 5;

[0048] Step two, open the pneumatic valve 19 and use the automatic control program, and charge the tank car to a set pressure of 0.1-0.5 MPaG;

[0049] Step three, put the pneumatic valve 6, the pneumatic valve 9 and the pneumatic valve 14 into the automatic program, set the opening time to 1-10 s and the opening interval to 20-30 s, set the pressure at each place to 0.1-0.8 MPaG, simultaneously introduce the loose air into the tank car through the loose pipeline, and convey the catalyst powder outward through the conveying main pipe under the air flow pressure; the second air charging pipeline intermittently ventilates the conveying main pipe, and is used for cutting the catalyst powder column in the conveying main pipe, forming the conveying form that the air column and the catalyst powder column are alternately arranged, and conveying the catalyst powder column forward under the air flow pressure;

[0050] Step four, observe the values of the pressure monitoring points, and put the automatic control program into operation;

[0051] Step five, when the catalyst tank car material position is low alarm, the system automatically closes the pneumatic valve 21, stops conveying, and the four-way air charging valve is automatically closed, and the pressure of the tank car starts to decrease to normal pressure.

[0052] Step six, disconnect the flexible connection 22, and the catalyst conveying is completed.

[0053] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A transport system for a low temperature Fischer-Tropsch synthesis catalyst, characterized by: The catalyst tank truck, the gas storage tank, the first gas charging pipeline, the second gas charging pipeline, the third gas charging pipeline, the fourth gas charging pipeline and the catalyst storage tank are connected through the conveying main pipe. The first gas charging pipeline is connected with the catalyst tank truck. The second gas charging pipeline is connected with the end of the conveying main pipe. The third gas charging pipeline and the fourth gas charging pipeline are connected with the conveying main pipe at different lengths. The third gas charging pipeline and the fourth gas charging pipeline are connected with the conveying main pipe at 1 / 3-1 / 2 and 1 / 2-2 / 3, respectively.

2. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The pressure reducing valve and the pneumatic valve are arranged on the four gas charging pipelines.

3. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The control system is connected with the pressure gauges, the pneumatic valves, the pressure reducing valves and the dust removal device.

4. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The pressure gauges are arranged downstream of the pressure reducing valves on the second gas charging pipeline, the third gas charging pipeline and the fourth gas charging pipeline.

5. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 4, characterised in that: The catalyst tank truck is provided with the material level meter and the pressure gauge.

6. The transport system of a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The dust removal device is connected with the top of the catalyst storage tank.

7. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The number of the cutting branch pipes is 4-10.

8. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The first gas charging pipeline includes the main gas inlet pipeline and the loose branch pipe assembly.

9. A transport system for a low temperature Fischer-Tropsch synthesis catalyst according to claim 1, characterized in that: The catalyst tank truck is filled with gas to 0.1-0.5 MPaG, and the loose air is introduced into the tank truck through the loose pipeline at the same time.

10. A method of transporting a low temperature Fischer-Tropsch synthesis catalyst, characterised by: The second gas charging pipeline is used for cutting the catalyst powder column in the conveying main pipe intermittently. The third gas charging pipeline and the fourth gas charging pipeline are used for supplementing air into the air column. The dust removal device is automatically operated. When the material level in the catalyst tank truck is lower than the set material level, the pneumatic valve is automatically closed, and the conveying is stopped. ​ ​

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