A double-support pre-reactor for hydrogen fluoride

Abstract

The invention discloses a double-support pre-reactor for hydrogen fluoride. The main shaft consists of a front shaft head, a hollow shaft and a rear shaft head. The front shaft head, the rear shaft head and the hollow shaft are welded into one. The front section of the hollow shaft corresponds to the main bearing section, the middle section of the hollow shaft corresponds to the fluorite feeding section and the reaction section, and the rear section of the hollow shaft corresponds to the extension and expansion section. The spiral main shaft is welded and processed by a 40CrMoNiA thick-walled tube and a 40CrMoNiA forging and subjected to quenching and tempering treatment. Spiral components of different materials and shapes are arranged on the main shaft, which not only improves the corrosion resistance of different sections of the pre-reactor, but also solves the welding problem between different alloys and reduces the cost.

Description

Technical Field

[0001] The invention relates to the technical field of chemical equipment, in particular to a reactor. Background Art

[0002] The hydrogen fluoride pre-reactor is a screw conveying device with mixing control and heating reaction.

[0003] The main shaft screw system of the hydrogen fluoride pre-reactor adopts a more than 5-meter-long hollow cantilever shaft spiral stirring propeller. Driven by the frequency conversion motor and the reducer, it has the function of continuous rotation and axial reciprocating movement. During the rotation process, the propeller blades reciprocate back and forth in the equipment, and have multiple functions such as mixing, kneading, and uniform material transportation. The spiral system stirs the blades on the sleeve to stir the fluorite to prevent the powdered fluorite from settling, so that the reaction proceeds smoothly. The by-product of the reaction of fluorite and sulfuric acid is gypsum. During the process, a gypsum film will be formed on the surface of the fluorite, which will hinder the reaction rate. Therefore, the main shaft screw needs to reciprocate to continuously transport the fluorite powder to fully react with sulfuric acid and speed up the reaction. The main shaft screw system of the pre-reactor is an important component of the entire equipment.

[0004] Ordinary spiral systems have short strokes, poor mixing effects, inadequate reactions, and heavy production loads on subsequent equipment. They are only suitable for conveying dry powders, not slurries. The dust raised during dry powder conveying is very large, and the system is easily blocked, causing mechanical failures, making it difficult for the equipment to operate continuously. The materials used are also mostly common materials that are processed and manufactured as a whole. The materials with poor abrasion resistance result in a short equipment life, high failure rate, and low output. The materials with high abrasion resistance increase costs and cause economic waste. The use of multiple materials makes it easy for cracks to occur during welding between different materials. Unreasonable welding methods may even directly lead to tearing and detachment of the blade welds during operation. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a double-support pre-reactor for hydrogen fluoride, comprising a shell, a feed hole is arranged on the shell, two sets of bearings are arranged at one end of the shell, a main shaft is arranged on the bearing, the main shaft is composed of a front shaft head, a hollow shaft, and a rear shaft head, and the front shaft head, the rear shaft head and the hollow shaft are welded into one body; the main bearing section is between the two sets of bearings; the front section of the hollow shaft corresponds to the main bearing section, the middle section of the hollow shaft corresponds to the fluorite feeding section and the reaction section, and the rear section of the hollow shaft corresponds to the extension and expansion section;

[0006] The blades are welded on the middle section of the hollow shaft, and the middle section of the hollow shaft is divided into nine sections;

[0007] The first spiral section is located in front of the fluorite powder inlet. In order to transport as much fluorite powder as possible to the reaction section and to prevent HF gas from entering the main bearing section, a four-head propeller blade is used. The continuous spiral blades can maximize the material transportation and form a material seal to overcome gas resistance.

[0008] The second and third sections are located below the fluorite powder inlet. The second and third sections are the main spiral sections for transporting fluorite powder. Therefore, single-head propeller blades made of carbon steel are used, which have strong conveying capacity and maximize the pushing of materials.

[0009] The fourth spiral section is located at the junction of the fluorite feeding section and the reaction section. At this position, the material reacts from powder to slurry. The first half of this section is in the fluorite feeding section and uses spiral blades. The second half is in the acid addition reaction section. Fluorite powder reacts with mixed acid to become slurry. The material has high viscosity and adheres to the blades. Therefore, a cleaning pin is required. Under the reciprocating motion of the spiral system, the slurry material on the blades is cleaned off. Diamond blades are used.

[0010] The fifth to ninth spirals are all in the acid-adding reaction section, where the reaction is most intense; and they all reciprocate around the cleaning pin, so they all adopt diamond-shaped blades and are made of Hastelloy as a whole;

[0011] After a violent reaction in the acid-adding reaction section, the material enters the extension and expansion section; a single fan-shaped paddle is used on the rear section of the hollow shaft in the extension and expansion section to increase the conveying capacity.

[0012] The blades from the first to the third sections are made of carbon steel; the blades from the fourth to the ninth sections are made of Hastelloy.

[0013] The blades from the fourth to the eighth section are welded with Stellite carbide.

[0014] The lengths of the first to ninth helical segments are different.

[0015] The advantages of the present invention are:

[0016] The main shaft screw system of the hydrogen fluoride pre-reactor ensures that the materials (fluorite and sulfuric acid) are fully reacted in the reaction section to form a slurry, and in the expansion section, they are crushed into powder and enter the reactor.

[0017] The spiral main shaft is made of 40CrMoNiA thick-walled tube and 40CrMoNiA forgings welded and processed after quenching and tempering. Spiral components of different materials and shapes are installed on the main shaft, which not only improves the corrosion resistance of different sections of the pre-reactor, but also solves the welding problem between different alloys and reduces costs.

[0018] Special propeller blades are used and welded evenly on the shaft and sleeve at a fixed angle to ensure that the blades only propel the material without returning it during the reciprocating propulsion; and that they crush and propel the material in the extension section without returning it.

[0019] Stellite carbide is overlaid on the blades to improve wear resistance.

[0020] The use of a more than 5-meter-long hollow cantilever shaft spiral stirring propeller has a safe technical level while greatly increasing the stirring stroke, making the pre-reaction more complete, improving production efficiency and product quality, and reducing system dust, achieving good environmental protection effects, and extending the service life of the reactor.

[0021] Therefore, the main shaft of the pre-reactor main shaft system design adopts a hollow shaft, and in order to increase the reaction time, the number of shaft sleeves is increased from eight to nine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 Schematic diagram of welding blades on the middle section of the hollow shaft. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings, as shown in the drawings:

[0025] The present invention comprises a shell 4, a feed hole 5 is arranged on the shell 4, two sets of bearings 6 are arranged at one end of the shell, a main shaft is arranged on the bearing, the main shaft is composed of a front shaft head, a hollow shaft, and a rear shaft head, and the front shaft head, the rear shaft head and the hollow shaft are welded into one body; the main bearing section is between the two sets of bearings; the front section of the hollow shaft corresponds to the main bearing section, the middle section of the hollow shaft corresponds to the fluorite feeding section and the reaction section, and the rear section of the hollow shaft corresponds to the extension and expansion section;

[0026] The double-support pre-reactor for hydrogen fluoride is composed of a front shaft head 1, a hollow shaft 2, and a rear shaft head 3. The front shaft head 1, the rear shaft head 3 and the hollow shaft 2 are welded into one body; the front section 21 of the hollow shaft corresponds to the main bearing section, the middle section 22 of the hollow shaft corresponds to the fluorite feeding section and the reaction section, and the rear section 23 of the hollow shaft corresponds to the extension and expansion section;

[0027] The blades are welded on the middle section of the hollow shaft, and the middle section of the hollow shaft is divided into nine sections;

[0028] The first spiral section is located in front of the fluorite powder inlet. In order to transport as much fluorite powder as possible to the reaction section and to prevent HF gas from entering the main bearing section, a four-head propeller blade is used. The continuous spiral blades can maximize the material transportation and form a material seal to overcome gas resistance.

[0029] The second and third sections are located below the fluorite powder inlet. The second and third sections are the main spiral sections for transporting fluorite powder. Therefore, single-head propeller blades made of carbon steel are used, which have strong conveying capacity and maximize the pushing of materials.

[0030] The fourth spiral section is located at the junction of the fluorite feeding section and the reaction section. At this position, the material reacts from powder to slurry. The first half of this section is in the fluorite feeding section and uses spiral blades. The second half is in the acid addition reaction section. Fluorite powder reacts with mixed acid to become slurry. The material has high viscosity and adheres to the blades. Therefore, a cleaning pin is required. Under the reciprocating motion of the spiral system, the slurry material on the blades is cleaned off. Diamond blades are used.

[0031] The fifth to ninth spirals are all in the acid-adding reaction section, where the reaction is most intense; and they all reciprocate around the cleaning pin, so they all adopt diamond-shaped blades and are made of Hastelloy as a whole;

[0032] After a violent reaction in the acid-adding reaction section, the material enters the extension and expansion section; a single fan-shaped paddle is used on the rear section of the hollow shaft in the extension and expansion section to increase the conveying capacity.

[0033] The blades from the first to the third sections are made of carbon steel; the blades from the fourth to the ninth sections are made of Hastelloy.

[0034] The blades from the fourth to the eighth section are welded with Stellite carbide.

[0035] The first to ninth helical segments are helices of unequal length.

[0036] The four-head propeller blade here refers to four spiral blades arranged in parallel; the single-head propeller blade refers to a blade arranged in a spiral; the diamond blade refers to a blade with a diamond-shaped cross-section.

[0037] The main shaft screw system of the hydrogen fluoride pre-reactor ensures that the materials (fluorite and sulfuric acid) are fully reacted in the reaction section to form a slurry, and in the expansion section, they are crushed into powder and enter the reactor.

[0038] The present invention adopts a hollow cantilever shaft spiral stirring propeller with a length of more than 5 meters. While having a safe technical level, it greatly increases the stirring stroke, makes the pre-reaction more complete, improves production efficiency and product quality, has less system dust, good environmental protection effect, and increases the service life of the reactor.

[0039] Hollow shafts take up a large space, but can reduce weight. According to material mechanics analysis, when the shaft transmits torque, the outer part has a greater effect on transmitting effective torque from the radial cross section. When the shaft needs to transmit a large torque, a thicker shaft diameter is required. Since the role of transmitting torque in the shaft center is small, hollow shafts are generally used to reduce the weight of the shaft.

[0040] Under the same material and cross-sectional area, the hollow shaft has stronger torsion resistance than the solid shaft and can withstand larger external torque. Under the same external torque, the hollow shaft saves material than the solid shaft. This can also be seen from the stress distribution of the circular cross section. When the maximum shear stress on the circumference of the solid shaft is close to the allowable shear stress, the shear stress in the middle part is still far from the allowable shear stress, and most of the material in the middle does not play its full role.

[0041] The main shaft screw system of the hydrogen fluoride pre-reactor has the function of continuous rotation and axial reciprocating motion, which makes the stirring more uniform, the fluorite and sulfuric acid kneading more fully, and has a strong conveying capacity under low-speed operation. It is very suitable for conveying paddle-shaped materials, has a wide range of adaptability to fluorite particle size, the equipment is not easy to be blocked, and has a strong ability to overcome HF gas resistance.

[0042] The strength and rigidity requirements for the main shaft of the hydrogen fluoride pre-reactor are extremely high. The material is 40CrMoNiA steel and is modulated as a whole, which greatly improves the strength and rigidity of the main shaft, ensures the safe operation of the equipment, and increases the service life of the equipment.

[0043] The reaction intensity at different positions of the pre-reactor is different, so the degree of blade abrasion is also different. Therefore, the blade is welded to the sleeve and then the sleeve is put on the main shaft, so that the severely abraded spiral section can be replaced separately. This solves the problem that the blade is directly welded to the main shaft, and it is difficult to repair the blade after it is abraded or damaged. The replacement project is huge and delays the production cycle.

[0044] According to the corrosion characteristics of the material in different sections of the pre-reactor, as well as the movement form of the sleeve and blade in the pre-reactor and the characteristics of contact with the material, sleeves and blades of different forms and materials are used in different sections. This method solves the welding problem of different materials, improves the service life of the equipment, and produces significant economic benefits and reduces costs.

Claims

1. A double-support pre-reactor for hydrogen fluoride, comprising a shell, a feed hole is arranged on the shell, two sets of bearings are arranged at one end of the shell, and a main shaft is arranged on the bearing, characterized in that: The main shaft is composed of a front shaft head, a hollow shaft and a rear shaft head, which are welded together. The main bearing section is between the two sets of bearings. The front section of the hollow shaft corresponds to the main bearing section, the middle section of the hollow shaft corresponds to the fluorite feeding section and the reaction section, and the rear section of the hollow shaft corresponds to the extension and expansion section. The blades are welded on the middle section of the hollow shaft, and the middle section of the hollow shaft is divided into nine sections; The first spiral section is located in front of the fluorite powder inlet. In order to transport as much fluorite powder as possible to the reaction section and to prevent HF gas from entering the main bearing section, a four-head propeller blade is used. The continuous spiral blades can maximize the material transportation and form a material seal to overcome gas resistance. The second and third sections are located below the fluorite powder inlet. The second and third sections are the main spiral sections for transporting fluorite powder. Therefore, single-head propeller blades made of carbon steel are used, which have strong conveying capacity and maximize the pushing of materials. The fourth spiral section is located at the junction of the fluorite feeding section and the reaction section. At this position, the material reacts from powder to slurry. The first half of this section is in the fluorite feeding section and uses spiral blades. The second half is in the acid addition reaction section. Fluorite powder reacts with mixed acid to become slurry. The material has high viscosity and adheres to the blades. Therefore, a cleaning pin is required. Under the reciprocating motion of the spiral system, the slurry material on the blades is cleaned off. The second half of this section uses diamond blades. The fifth to ninth spirals are all in the acid-adding reaction section, where the reaction is most intense; and they all reciprocate around the cleaning pin, so they all adopt diamond-shaped blades and are made of Hastelloy as a whole; After a violent reaction in the acid-adding reaction section, the material enters the extension and expansion section; a single fan-shaped paddle is used on the rear section of the hollow shaft in the extension and expansion section to increase the conveying capacity.

2. The double-support pre-reactor for hydrogen fluoride according to claim 1, characterized in that: The blades from the first to the third sections are made of carbon steel; the blades from the fourth to the ninth sections are made of Hastelloy.

3. The double-support pre-reactor for hydrogen fluoride according to claim 1, characterized in that: The blades from the fourth to the eighth section are welded with Stellite carbide.

4. The double-support pre-reactor for hydrogen fluoride according to claim 1, characterized in that: The lengths of the first to ninth helical segments are different.

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