Volume and Batch OutputDetermine the effective volume based on production needs (usually 70% -80% of the nominal volume is taken as the actual feeding amount), with options of 50-500L for small/medium scale trials, and 1000-10000L or more for industrial production.

Material SelectionThe main material is preferably 316L stainless steel (resistant to slight corrosiveness of isocyanates, polyols, and other raw materials), and the inner wall needs to be mirror polished (Ra ≤ 0.8 μ m) to reduce material residue and wall hanging.

mixing systemIn response to the change in material viscosity from low to high in polyurethane reactions (such as viscosity reaching over 10000cP in the later stage of prepolymer reactions), it is recommended to usecoaxial mixerAnchor type stirring is installed at the bottom (to fit the kettle wall and prevent material deposition), vortex wheel stirring is installed in the middle (to enhance radial mixing), and a guide tube is installed at the top (to improve axial circulation). The stirring speed can be adjusted by a variable frequency motor (5-100r/min) to meet the needs of different reaction stages.

sealing form: AdoptingMechanical seal+magnetic sealDual design, targeting volatile and toxic raw materials such as isocyanates, ensuring zero leakage (leakage rate ≤ 0.1mL/h), avoiding material loss and safety risks.

Design of Temperature Control SystemAdopting a composite temperature control structure of jacket and inner coil, the jacket is filled with heat transfer oil (heating) or chilled water (cooling), and the inner coil is used for emergency cooling (to deal with uncontrolled reaction heat release). matchpreparePID intelligent temperature controllerThe control accuracy can reach ± 1 ℃, real-time monitoring of the temperature inside the kettle and automatic switching of heating/cooling modes.

Heat release suppression strategy: In view of the strong exothermic characteristics of polyurethane reaction, the "gradient temperature rise method" is adopted in the feeding stage: the initial temperature is controlled at 40-60 ℃ (reducing the initial reaction rate), and gradually rises to 80-120 ℃ (accelerating the reaction) with the reaction. At the same time, the frequency conversion regulation of jacket flow is used to avoid gel caused by local overheating.

Atmospheric/Micropressure ReactionFor reactions such as prepolymer synthesis, they are usually carried out under normal pressure, and the system sealing (leakage rate ≤ 0.5kPa/h) needs to be ensured to prevent moisture from entering the air and causing hydrolysis of isocyanates.

Vacuum degassing demandIf producing high-purity polyurethane (such as elastomers), a vacuum system (ultimate vacuum ≤ -0.095MPa) is required to remove bubbles and small molecule volatiles in the later stage of the reaction. The vacuum degree is automatically adjusted by a butterfly valve to avoid material boiling.

Leakage monitoringInstall infrared gas sensors (detecting isocyanate concentration, response time ≤ 1s) at the flange of the kettle body and the sealing of the mixing shaft. When the concentration exceeds 0.02mg/m ³, the system will automatically trigger an audible and visual alarm and cut off the feed pump.

Overtemperature and overpressure protectionThe kettle is equipped with a bimetallic thermometer (on-site display) and a thermocouple (remote control), and the pressure is monitored by a pressure gauge and a pressure transmitter; When the temperature exceeds the set value of 10 ℃ or the pressure exceeds 0.1MPa, the emergency cooling valve will automatically open (to introduce low-temperature chilled water), and the safety valve (with a popping pressure of 0.15MPa) will forcibly release pressure.

Emergency Shutdown System (ESD)Integrate an ESD module independent of the control system. When a large amount of toxic gas leakage, a broken mixing shaft, or personnel pressing the emergency stop button is detected, the heating source is immediately cut off, the feed valve is closed, the ventilation system is turned on (air exchange rate ≥ 10 times/h), and the materials in the kettle are transferred to the emergency storage tank.

PLC integrated controlAdopting Siemens S7-1200 series PLC, it realizes the linkage control of feed quantity (controlled by electromagnetic flowmeter+variable frequency pump, accuracy ± 1%), mixing speed (variable frequency regulation), temperature, and pressure, supports preset more than 10 process formulas, and one click start of production process.

human-computer interactionEquipped with a 10 inch touch screen, it displays real-time response curves (temperature time, pressure time), supports online parameter modification, historical data query (stored for ≥ 1 year), and has permission management function (graded authorization for operators and administrators).

Energy consumption monitoringReal time heating/cooling energy consumption is recorded through electric energy meters and flow meters. The system automatically analyzes the energy consumption per unit product and recommends a heating rate (such as shortening the heating time from 2 hours to 1.5 hours while ensuring the reaction, reducing energy consumption by 15%).

remote operation and maintenanceSupports 4G/5G module access, engineers can view device operation status through a mobile app, remotely diagnose faults (such as sensor drift, valve jamming), and reduce downtime.

Daily checkConfirm that the mixing motor is running with no abnormal noise, there is no leakage at the sealing point, and the temperature control system is displaying normally.

Weekly maintenanceClean the jacket inlet filter (to prevent impurities from blocking), check the manual tripping function of the safety valve, and calibrate the zero point of the gas sensor.

Monthly maintenanceDisassemble the mechanical seal of the mixing shaft, replace the wear-resistant ring (made of polytetrafluoroethylene material, resistant to aging), and check the pressure loss of the heating/cooling pipeline (ensuring ≤ 0.1MPa).

Annual major overhaulConduct a water pressure test on the kettle body (test pressure 1.5 times the working pressure), replace aging thermocouples and pressure transmitters, and verify the accuracy of the PID control system.

Waste gas recoveryThe volatile isocyanates are recovered through a condensation system (condensation temperature ≤ 5 ℃) with a recovery rate of ≥ 95%. The uncondensed gas is treated by an activated carbon adsorption tower (adsorption efficiency ≥ 99%) before being discharged, meeting the Comprehensive Emission Standards for Air Pollutants.

wastewater treatmentAfter the equipment cleaning wastewater is pretreated in the neutralization tank (adjusted to pH 6-9), it enters the factory sewage treatment plant to avoid direct discharge of nitrogen-containing wastewater.

waste heat utilizationPreheat the high-temperature materials (80-100 ℃) in the later stage of the reaction through a heat exchanger to reduce the load on the heating system, resulting in an energy-saving rate of 10% -15%.

frequency conversion controlThe mixing motor and circulating pump adopt frequency conversion technology, which automatically adjusts the speed according to the viscosity of the material, saving 20% -30% of electricity compared to fixed frequency equipment.