CN216646382U - Visual fixed bed reactor for evaluating hydrazine nitrate in catalytic decomposition nitric acid - Google Patents

Abstract

The utility model discloses a visual fixed bed reactor for evaluating and catalyzing and decomposing hydrazine nitrate in nitric acid, which consists of a reactor cylinder, a feeding coil, a jacket shell, a feed liquid output core pipe, an orifice plate and a screw cap. The feed liquid output core pipe is movable and used for fixing the catalyst bed layer and preventing the catalyst bed layer from loosening in the reaction process. The reactor cylinder and the feeding coil are arranged in the jacket shell, so that feed liquid preheating and catalyst bed layer heating are simultaneously carried out. The utility model has the advantages of simple assembly, convenient heating and small occupied space, and can effectively save energy consumption.

Description

Visualized Fixed Bed Reactor for Evaluation of Catalytic Decomposition of Hydrazine Nitrate in Nitric Acid

technical field

The utility model belongs to the field of nuclear power waste treatment and environmental protection, in particular to a laboratory-use visual fixed-bed reactor for evaluating the catalytic decomposition of hydrazine nitrate in nitric acid.

Background technique

Nuclear power is a green, low-carbon and clean energy with high technological maturity, and it is an important and preferred technical route for human beings to solve energy problems in the future. However, the safety of highly radioactive waste, namely "spent fuel", is one of the main factors restricting the large-scale promotion and application of nuclear power. The overall utilization rate of nuclear fuel in nuclear power reactors is not high. Spent fuel containing unconverted uranium is an important nuclear element resource. At present, the nuclear fuel closed cycle route is mostly adopted to separate and purify nuclear elements such as uranium, plutonium and neptunium in spent fuel for further utilization. . For example, the PUREX process: dissolving spent fuel rods with nitric acid, extracting tributyl phosphate with n-dodecane organic diluent, and reducing and stripping with reducing agents such as hydrazine nitrate and/or hydroxylamine nitrate to achieve separation, purification and enrichment of various nuclear elements . A large amount of nitric acid waste liquid containing hydrazine nitrate will be produced in this type of process. According to the principle of minimizing radioactive waste in the post-processing of spent fuel, the waste liquid should be recycled in the subsequent process of nitric acid, and the residual residue should be vitrified and solidified for deep burial. . Hydrazine nitrate has strong reducibility and is a high-energy, easily oxidizable and explosive substance. In order to eliminate the risk of explosion during the concentrated treatment of waste liquid, the hydrazine nitrate needs to be removed. The method of removing hydrazine nitrate mainly includes adding an oxidizing agent such as sodium nitrite or introducing dinitrogen tetroxide gas, etc., and oxidizing hydrazine nitrate into nitrogen, water, nitrogen oxides and other products for removal. The disadvantage is: the consumption of oxidant. It is large, expensive, and the reaction is extremely violent, and there are certain safety risks; when using sodium nitrite as an oxidant, it is easy to generate new solid waste sodium nitrate; the utilization rate of nitrogen dioxide is low and there is a risk of leakage. The continuous catalytic decomposition of hydrazine nitrate in spent fuel waste liquid has the advantages of safety, efficiency and economy. However, spent fuel waste liquid is usually radioactive. Considering the practical application, it is difficult for traditional reactors to prevent the leakage of feed liquid during catalyst replacement. , the reaction process is a large-scale in-situ gas production reaction, which is easy to cause abrasion to the catalyst and make the bed loose. Based on this, it is necessary to provide a reaction device that prevents the catalyst bed from loosening and can easily and quickly replace the catalyst. Continuous catalytic technology generally adopts fixed bed device, trickle bed device, fluidized bed device, etc., among which fixed bed device is mostly used. The preheating of the reaction liquid and the heating of the reactor in the traditional fixed bed device are generally carried out separately, and both are heated by electric heating; the traditional fixed bed device also has the problems of inconvenient disassembly of the reactor and complicated operation. The device used in the laboratory is mainly easy to build and easy to operate. The traditional fixed bed device takes up too much space due to its complex structure. Secondly, the traditional fixed bed device is made of non-transparent materials, which is inconvenient to observe the reaction state of the catalyst on the fixed bed and the fluid dynamics involved in the reaction, and it is difficult to observe the experimental phenomenon in the experimental stage. Timely detection and control of the reaction will make it difficult to improve the experimental plan, and also make the fixed-bed reaction in the experimental stage dangerous.

Utility model content

In order to solve the problems of complex structure, large occupied space and inconvenient operation of traditional fixed-bed devices, the utility model provides a laboratory-use visual fixed-bed reactor for evaluating catalytic decomposition of hydrazine nitrate in nitric acid, which can be effectively used for evaluating catalysts performance.

The technical scheme adopted by the utility model to solve the technical problem is as follows:

A visual fixed-bed reactor for evaluating the catalytic decomposition of hydrazine nitrate in nitric acid, characterized in that the reactor includes a reactor barrel, a feeding coil, a jacket shell, and a material-liquid output core tube all made of transparent materials , orifice plate;

The jacket shell is a hollow closed chamber surrounded by the shell;

The reactor barrel is a hollow barrel with upper and lower ends open, and the lower open end of the barrel is connected with one end of the feeding coil;

The reactor barrel and the feeding coil are placed in the jacket shell, the upper open end of the reactor barrel extends through the jacket shell to the outside of the jacket shell, and a material is connected to the upper open end of the reactor barrel. Liquid output core tube; the other end of the feeding coil extends through the jacket shell to the outside of the jacket shell; the jacket shell is provided with a thermal fluid inlet and a thermal fluid outlet;

A perforated plate is laterally arranged in the lower part of the reactor cylinder, and the perforated plate is a flat plate with through holes. as a chamber for filling the ceramic ring

The material and liquid output core tube is a hollow tube, and its outer diameter is consistent with the inner diameter of the reactor cylinder.

The screw cap is provided with a through hole, and one end of the material and liquid output core pipe is inserted into the reactor cylinder through the through hole of the screw cap and the upper open end of the reactor barrel, and the reactor barrel extending out of the jacket shell is inserted into the reactor barrel. The outer wall surface of the upper open end of the round body is provided with external threads, the nut is screwed on the upper open end of the reactor cylinder, and a sealing O ring is arranged between the nut and the upper open end. The core tube and nut are sealed with fluororubber sealing O-rings.

The feed liquid output core pipe is located above the catalyst bed.

The reactor cylinder is made of quartz or glass, the feeding coil is a spirally wound quartz or glass tube, the jacket shell is a cavity made of quartz or glass, and the material and liquid output core tube is polytetrafluoroethylene, The tube body is made of quartz or glass, and the orifice plate is a flat plate made of quartz or glass.

The material-liquid output core pipe of the utility model is movable, and is used for fixing the catalyst bed to prevent the catalyst bed from loosening during the reaction. Both the reactor barrel and the feed coil are placed in the jacket shell to realize the simultaneous preheating of the feed liquid and the heating of the catalyst bed. The utility model has the advantages of simple assembly, convenient heating, small occupied space, and can effectively save energy consumption.

The beneficial effects of the present utility model are:

(1) The structure of the reactor is simple, and the catalyst loading is convenient.

(2) The preheating of the reaction feed liquid and the heating of the reactor are realized at the same time, the energy consumption is saved, and the heating method is convenient.

(3) Quartz or glass material is used, which is convenient to observe the reaction process and reactant state, and has strong acid corrosion resistance, which effectively improves the safety of the experiment.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Description of reference numerals: 1-reactor barrel, 2-feeding coil, 3-jacket shell, 4-material liquid output core tube, 5-orifice plate, 6-nut, 7-heat transfer fluid inlet, 8- The outlet of the thermal fluid, 9- The chamber for filling the catalyst, 10- The chamber for filling the porcelain ring.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The structure of a visual fixed-bed reactor for evaluating the catalytic decomposition of hydrazine nitrate in nitric acid is as follows. The reactor includes a reactor barrel 1, a feeding coil 2, a jacket shell 3, and a material-liquid output core, all of which are made of transparent materials. Tube 4, orifice plate 5;

The jacket shell 3 is a hollow airtight chamber surrounded by the shell;

The reactor barrel 1 is a hollow barrel with upper and lower ends open, and the lower open end of the barrel is connected to one end of the feeding coil 2;

The reactor barrel 1 and the feeding coil 2 are placed in the jacket shell 3, and the upper open end of the reactor barrel 1 extends through the jacket shell 3 to the outside of the jacket shell 3, and is in the reactor barrel 3. The upper open end of the body 1 is connected with a material and liquid output core tube 4; the other end of the feeding coil 2 extends through the jacket shell 3 to the outside of the jacket shell 3; the jacket shell 3 is provided with a thermal fluid Inlet 7 and thermal fluid outlet 8;

A perforated plate 5 is laterally arranged in the lower part of the reactor cylinder 1, and the perforated plate 5 is a flat plate with through holes. The inside of the reactor barrel 1 below the orifice plate 5 serves as a chamber 10 for filling ceramic rings;

The feed liquid output core tube 4 is a hollow tube, the outer diameter of which is the same as the inner diameter of the reactor barrel 1 .

The nut 6 is provided with a through hole, and one end of the material and liquid output core tube 4 is inserted into the reactor barrel through the through hole of the nut 6 and the upper open end of the reactor barrel, and extends to the outside of the jacket shell 3 The outer wall of the circular upper open end of the reactor barrel 1 is provided with external threads, the nut 6 is screwed on the upper open end of the reactor barrel, and a sealing O ring is provided between the nut and the upper open end. The cylinder body 1, the material and liquid output core tube 4 and the nut 6 are sealed with a fluororubber sealing O-ring.

The feed liquid output core pipe 4 is located above the catalyst bed.

The reactor barrel 1 is a quartz barrel, the feed coil 2 is a spirally wound glass tube, the jacket shell 3 is glass, the feed liquid output core tube 4 is a transparent polytetrafluoroethylene tube, and the orifice plate 5 is a quartz flat plate .

The ruthenium-based catalyst is a carbon-supported ruthenium catalyst with a ruthenium mass content of 5%;

Example 1

The orifice plate 5 is placed in the reactor barrel 1, 10g of ruthenium-based catalyst is loaded, the catalyst bed is pressed with the feed liquid output core pipe 4, the feed liquid output core pipe 4 is fixed with the nut 6, and the feed liquid output core pipe 4 is fixed from the thermal fluid inlet 7. The circulating water was introduced, and the temperature of the circulating water was set to 60 °C. The feed liquid of 0.1 mol/L hydrazine nitrate, 1.0 mol/L nitric acid and 0.06 g/L hexavalent uranium was passed through the feed coil 2 at a flow rate of 0.5 mL/min, and after preheating, it entered the catalytic bed for reaction. The feed liquid after the reaction was sampled and analyzed, and the content of hydrazine nitrate in the solution was 0.0002 mol/L.

Example 2

The orifice plate 5 is placed in the reactor barrel 1, 15g of ruthenium-based catalyst is loaded, the catalyst bed is pressed with the feed liquid output core pipe 4, and the feed liquid output core pipe 4 is fixed with the nut 6, and the feed liquid output core pipe 4 is fixed from the thermal fluid inlet 7. The circulating water was introduced, and the temperature of the circulating water was set to 60 °C. The feed liquid of 0.1 mol/L hydrazine nitrate, 1.0 mol/L nitric acid and 0.06 g/L hexavalent uranium was passed through the feed coil 2 at a flow rate of 1.5 mL/min, and after preheating, it entered the catalytic bed for reaction. The feed liquid after the reaction was sampled and analyzed, and the content of hydrazine nitrate in the solution was 0.00001 mol/L.

Example 3

The orifice plate 5 is placed in the reactor barrel 1, 10g of ruthenium-based catalyst is loaded, the catalyst bed is pressed with the feed liquid output core pipe 4, the feed liquid output core pipe 4 is fixed with the nut 6, and the feed liquid output core pipe 4 is fixed from the thermal fluid inlet 7. The circulating water was introduced, and the temperature of the circulating water was set to 80 °C. The feed liquid of 0.1 mol/L hydrazine nitrate, 1.0 mol/L nitric acid and 0.06 g/L hexavalent uranium was passed through the feeding coil 2 at a flow rate of 1 mL/min, and after preheating, it entered the catalytic bed for reaction. The feed liquid after the reaction was sampled and analyzed, and no hydrazine nitrate was detected in the solution.

Example 4

The orifice plate 5 is placed in the reactor barrel 1, 6g of ruthenium-based catalyst is loaded, the catalyst bed is compressed with the feed liquid output core pipe 4, and the feed liquid output core pipe 4 is fixed with the nut 6, and the feed liquid output core pipe 4 is fixed from the thermal fluid inlet 7. The circulating water was introduced, and the temperature of the circulating water was set to 50 °C. The feed liquid of 0.1 mol/L hydrazine nitrate, 1.0 mol/L nitric acid and 0.06 g/L hexavalent uranium was passed through the feeding coil 2 at a flow rate of 0.3 mL/min, and after preheating, it entered the catalytic bed for reaction. The feed liquid after the reaction was sampled and analyzed, and the content of hydrazine nitrate in the solution was 0.00005 mol/L.

Example 5

The orifice plate 5 is placed in the reactor barrel 1, 10g of ruthenium-based catalyst is loaded, the catalyst bed is pressed with the feed liquid output core pipe 4, the feed liquid output core pipe 4 is fixed with the nut 6, and the feed liquid output core pipe 4 is fixed from the thermal fluid inlet 7. The circulating water was introduced, and the temperature of the circulating water was set to 90 °C. The feed liquid of 0.1 mol/L hydrazine nitrate, 1.0 mol/L nitric acid and 0.06 g/L hexavalent uranium was passed through the feed coil 2 at a flow rate of 0.5 mL/min, and after preheating, it entered the catalytic bed for reaction. The feed liquid after the reaction was sampled and analyzed, and no hydrazine nitrate was detected in the solution.

Claims (5)

1. the visual fixed-bed reactor for evaluating the use of hydrazine nitrate in the catalytic decomposition of nitric acid, it is characterized in that, this reactor comprises the reactor barrel (1), feeding coil (2), jacket made of transparent material. shell (3), material and liquid output core tube (4), orifice plate (5); The jacket casing (3) is a hollow airtight chamber surrounded by the casing; The reactor barrel (1) is a hollow barrel with upper and lower ends open, and the lower open end of the barrel is connected to one end of the feeding coil (2); The reactor barrel (1) and the feed coil (2) are placed in the jacket shell (3), and the upper open end of the reactor barrel (1) protrudes through the jacket shell (3) to the clamping Outside the jacket shell (3), a material and liquid output core pipe (4) is connected to the upper open end of the reactor barrel (1); the other end of the feeding coil (2) extends through the jacket shell (3) out to the outside of the jacket shell (3); the jacket shell (3) is provided with a heat transfer liquid inlet (7) and a heat transfer liquid outlet (8); A perforated plate (5) is laterally arranged in the lower part of the reactor cylinder (1), and the perforated plate (5) is a flat plate with through holes, and is located in the reactor cylinder (1) above the perforated plate (5) as a The chamber (9) for filling the catalyst is located in the reactor barrel (1) below the orifice plate (5) as the chamber (10) for filling the porcelain ring. 2 . The visualized fixed bed reactor according to claim 1 , wherein the material and liquid output core tube ( 4 ) is a hollow tube, and its outer diameter is consistent with the inner diameter of the reactor barrel ( 1 ). 3 . 3. The visualized fixed-bed reactor according to claim 1 or 2, characterized in that, the screw cap (6) is provided with a through hole, and one end of the material and liquid output core tube (4) passes through the through hole of the screw cap (6). The hole and the upper open end of the reactor barrel are inserted into the reactor barrel, and an external thread is provided on the outer wall surface of the circular upper open end of the reactor barrel (1) extending to the outside of the jacket shell (3), The nut (6) is screwed on the upper open end of the reactor barrel, a sealing O-ring is arranged between the nut and the upper open end, the reactor barrel (1), the material and liquid output core tube (4) and the nut (6) Fluorine rubber sealing O-ring is used for sealing. 4. The visualized fixed bed reactor according to claim 1, characterized in that, the feed liquid output core pipe (4) is located above the catalyst bed. 5. The visualized fixed-bed reactor according to claim 1, wherein the reactor barrel (1) is a barrel made of quartz or glass, and the feeding coil (2) is a spirally wound quartz or glass tube , the jacket shell (3) is a cavity made of quartz or glass, the material and liquid output core tube (4) is a tube made of PTFE, quartz or glass, and the orifice plate (5) is made of quartz or glass flat.

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