Jinzong Machinery | Cosmetic Machinery & Chemical Machinery Manufacturers
Application Scope and Operational Safety of Magnetic Reaction Kettles
The magnetic reaction kettle is an innovative application of magnetic transmission technology in reaction vessels, fundamentally resolving the shaft seal leakage issues that traditional packing and mechanical seals could not overcome. This leak-proof and contamination-free device is currently the most ideal equipment for high-temperature and high-pressure chemical reactions in China, especially for processes involving flammable, explosive, or toxic media, where its advantages are particularly evident. However, while utilizing this technology, we must not overlook the associated safety concerns. Next, Jinzong Enterprise will guide you through the essential knowledge for the safe operation of magnetic reaction kettles.
I. Precautions Before Use
Sealing Performance
The magnetic reaction kettle is a precision device. Its sealing relies on the contact between sealing rings in a tapered surface configuration, achieved by tightening the main bolts to press them together. Special care must be taken to protect the tapered sealing surfaces from damage caused by impact. When installing the lid, first position the kettle body properly, then carefully place the lid in its fixed position. When tightening the main bolts, do so gradually and evenly in a diagonal and symmetrical sequence multiple times. Avoid tilting the lid to one side to ensure an effective seal. Do not exceed the specified tightening torque, as this may damage or accelerate wear on the sealing surfaces. All threaded connections should be coated with oil or graphite mixed with oil during assembly. If the sealing surface is damaged, it must be machined and repaired to restore its proper sealing performance.
Sealing Operation
The gas inlet and vent valve are sealed using needle valves. To close, gently rotate the valve needle to press against the sealing surface. This will achieve an effective seal. Do not apply excessive force, as it may damage the sealing surface.
Heating and Pressure Testing
Before use, the magnetic reaction kettle must undergo a heating and pressure test for leakage. The test medium can be air or nitrogen, though inert gases are preferred. The use of oxygen or other flammable and explosive gases is strictly prohibited. Heating and pressurization must be carried out gradually. The heating rate should not exceed 80°C per hour. For pressure testing, connect the kettle's inlet valve to a compressor (or high-pressure pump) using a connecting pipe. Pressurization should be done incrementally, in steps of 20% of the working pressure, with a 5-minute hold at each step. Once the test pressure is reached, hold for 30 minutes to check for leaks. The test pressure should be 100–105% of the working pressure. If leakage is detected, reduce the pressure first before appropriately tightening the nuts and connections. Never tighten nuts or connections under high pressure.
Cooling Process
Sudden cooling or heating during the reaction is prohibited to prevent excessive thermal stress from causing cracks in the kettle body. After the reaction is complete, cool the kettle first. This can be done by water cooling (for exothermic reactions) or air cooling. Then, release the high-pressure gas inside to reduce the pressure to normal levels. Finally, loosen and remove the bolts symmetrically and evenly. Special care must be taken during the lid-opening process to protect the sealing surfaces. Lift the lid evenly to avoid collisions that could damage the sealing rings of the lid and body.
Post-Operation Handling
After each operation, clean any residue from the kettle body and lid. The sealing surfaces of the magnetic reaction kettle should be cleaned frequently and kept dry. Do not use hard or rough soft materials for cleaning.
II. Safe Operating Procedures
Pre-Use Preparations
Before charging materials, inspect the reactor for contamination. Clean the inner wall, agitator, cooling coil, temperature probe sleeve, and mating surfaces of the magnetic reaction kettle with ethanol, followed by rinsing with distilled water. After rinsing, wipe thoroughly with cotton or silk cloth soaked in ethanol to prevent cross-contamination of materials. Before use, check that all valves are clear, especially the ports for the pressure gauge and rupture disc. Pay particular attention to the inlet duct for any blockages. If contaminated or clogged, disassemble the duct and inlet pipe from the kettle lid, clean them, and then reinstall.
Sealing Inspection
After cleaning and drying the kettle body, perform a sealing inspection first. Place the kettle body into the heating furnace, aligning the protrusions with the grooves. Gently rotate the kettle body to ensure it sits steadily. Slowly and steadily join the kettle body and lid, taking special care to protect the sealing surfaces and avoid collisions that could damage the sealing rings of the lid and body. After closing, check that the upper and lower interfaces of the reactor are aligned. Gently rotate the lid to confirm it is level and the sealing ring is in good contact. Add the gasket and begin installing the screws.
Precautions for Screw Installation
When installing screws, they must be matched to their correct positions. Tighten them by hand first, then use a torque wrench to tighten in a crisscross pattern symmetrically to avoid uneven force distribution. Do not tighten the screws to the final torque in one step; instead, tighten diagonal screws multiple times, gradually increasing the force symmetrically.
Airtightness Check
When checking airtightness, first check that all valves (solid feed port, kettle vent valve, inlet valve, etc.) are tightened (snug only, avoid excessive force). After ensuring the controller's agitation switch and speed control/heating switch are set to zero, turn on the control box power and its display switch.
Pressure Test Operation
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Connect Nitrogen
Connect the nitrogen cylinder to the inlet of the magnetic reaction kettle using a conduit, tightening the relevant screws. Open the main valve and the pressure reducing valve of the nitrogen cylinder. First, adjust the pressure reducing valve to the pressure required for the experiment, then open the reactor inlet valve to allow gas to slowly fill the reactor. When the pressure displayed on the reactor stabilizes and matches the set pressure on the nitrogen cylinder, close the reactor inlet valve and the nitrogen cylinder outlet valve in sequence. Record the pressure value displayed on the reactor and observe after half an hour for any changes. -
Check for Leaks
If a significant pressure drop is observed, check for leaks. Use soapy water to inspect all potential leak points on the magnetic reaction kettle. Key areas include: the interfaces between the kettle lid and the inlet pipe, outlet pipe, and pressure gauge; the needle valve interfaces at the inlet and outlet; the sealing ring between the kettle body and lid; and the thermometer probe socket. If leakage is found, release the pressure first, then tighten the corresponding leak point before repressurizing for a leak test. After confirming no leaks, release the pressure and rinse off the soapy water with deionized water. -
Disconnect Nitrogen
Ensure all pressure inside the kettle is released. Close the main valve and pressure reducing valve of the nitrogen cylinder, and vent any residual pressure in the pipeline. Use a torque wrench to loosen the main nuts in a symmetrical, crisscross pattern. Slowly and steadily separate the kettle body from the lid, taking special care to protect the sealing surfaces and avoid collisions that could damage the sealing rings.
Charging Operation
After the pressure test is complete, proceed with charging operation. Add reaction materials and solvent into the clean, dry magnetic reaction kettle. Follow the above steps to seal the kettle body and lid properly.
Pre-Reaction Checks
Check that all valves (solid feed port, kettle vent valve, inlet valve, etc.) are tightened (snug only, avoid excessive force). Ensure the controller's agitation switch and speed control/heating switch are set to zero, and confirm that the thermocouple is inserted into the kettle lid and displays temperature normally. Then, turn on the control box power and its display switch. Open the cooling water supply for the agitator shaft, then turn on the agitation switch. Control the agitation speed via the speed regulator to start mixing.
Nitrogen Purging
Connect the nitrogen cylinder to the inlet of the magnetic reaction kettle using a conduit, tightening the relevant screws. Open the main valve and the pressure reducing valve of the nitrogen cylinder. First, adjust the pressure reducing valve to approximately 1 MPa, then open the reactor inlet valve to allow gas to slowly fill the reactor. When the pressure displayed stabilizes and matches the set pressure on the cylinder, close the reactor inlet valve. After agitating for about 3-5 minutes, open the vent valve to release the pressure. Once fully vented, close the vent valve. Repeat the pressurization and venting process 3-5 times. Finally, ensure no residual pressure remains in the kettle and close the vent valve.
Hydrogen Charging
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Pipeline Connection
Close the main valve and pressure reducing valve of the nitrogen cylinder, and vent any residual pressure in the pipeline. Disconnect the magnetic reaction kettle from the nitrogen cylinder. Connect the magnetic reaction kettle to the hydrogen cylinder using a conduit, tightening the relevant screws. -
Hydrogen Pressure Adjustment
Open the main valve and pressure reducing valve of the hydrogen cylinder. First, adjust the pressure reducing valve to approximately 0.5-1 MPa, then open the reactor inlet valve to allow gas to slowly fill the reactor. When the pressure displayed stabilizes and matches the set pressure on the cylinder, close the reactor inlet valve. Connect the outlet of the vent valve via a pipe leading outdoors. After agitating for about 3-5 minutes, open the vent valve to release the pressure. Once fully vented, close the vent valve. Repeat the pressurization and venting process 3-5 times. Then, adjust the pressure reducing valve of the hydrogen cylinder to the pressure required for the reaction. Slowly introduce gas into the reactor until the pressure gauge displays the required pressure. Close the inlet valve, and the main and pressure reducing valves of the hydrogen cylinder. -
Pre-Heating Check
Use soapy water again to check the inlet and vent valve for hydrogen leaks. Only after confirming no hydrogen leakage, turn on the controller heating switch. Set the reaction temperature incrementally to prevent excessive heating temperature. Adjust the voltage to a reasonable range, ensuring the heating rate does not exceed 80°C/h. Start the heating program to begin the reaction. -
Parameter Monitoring and Control
After the reaction starts, closely monitor changes in all parameters (pressure, temperature, speed), especially pressure. If any abnormality is detected, immediately turn off the heating switch and report to the department supervisor. If the temperature is too high, cool it down by connecting cooling water to the cooling coil. If the pressure is too high, reduce it by cooling or venting through the vent valve. Hydrogen must be vented outdoors through a pipe!
Sampling During Reaction
If sampling is required during the reaction, material can be discharged through the inlet port for analysis, but only if the reaction system is homogeneous and will not precipitate solids. If heterogeneous catalysts like palladium on carbon or Raney nickel are used, stop agitation before sampling, let stand for about 10 minutes, and then sample. If multiple samples are needed for analysis, the initial discharge from the pipe is residual material and may not reflect the true reaction conditions inside the kettle. Discharge about 20 ml first before collecting the sample for analysis.
Post-Reaction Operations
After the reaction is complete, turn off heating and set the temperature to room level. Allow natural cooling or cool by circulating water through the cooling coil. When cooled below 40°C, open the reactor vent valve to slowly release all pressure. Use a torque wrench to loosen the main nuts in a symmetrical, crisscross pattern. Slowly and steadily separate the kettle body from the lid, taking special care to protect the sealing surfaces and avoid collisions that could damage the sealing rings.
Reactor Cleaning
Remove the kettle body, pour out the materials, and wash out all residual material from the kettle using solvent. Wash the kettle body, lid, and sampling pipe sequentially with ethanol and water. Wipe the tapered sealing surfaces clean with a soft cloth or paper. Cleaning should be performed immediately after discharging to avoid difficulties due to solvent evaporation. After cleaning, place the kettle body and lid in a ventilated area to dry.
III. Additional Precautions
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Operation of the reactor must strictly adhere to regulations. Do not operate alone; a minimum of two personnel is required for experiments.
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During reactor operation, turn on the exhaust fan to ensure adequate ventilation.
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Do not loosen nuts or strike the magnetic reaction kettle when it is under internal pressure.
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For male-female nut connections (such as those for the inlet pipe, exhaust pipe, and the connecting pipes for the pressure gauge on the kettle lid), only rotate the nuts themselves. Do not allow the two sealing surfaces to rotate against each other.
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Continuously monitor the pressure gauge readings during operation. Operation under conditions exceeding temperature or pressure limits is strictly prohibited.
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If gas leakage is detected during the experiment, stop heating and halt the experiment immediately. Do not loosen nuts at high temperatures.
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Do not leave the experiment unattended during its progress.
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The reaction kettle is not resistant to strong acids. The use of strong acids such as hydrochloric acid, sulfuric acid, or nitric acid in the reaction mixture is prohibited.
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Prior use of the kettle requires permission from the responsible person. Anyone using the kettle must read the operation manual thoroughly beforehand.
Tel: +86-758-3623881
E-mail: sales@jinzong.com.cn
Fax: +86-758-3623880
Address: NO.3 Kangtai St., Hi-tech Dist., Zhaoqing City, Guangdong Province, China（526238）