1Microchannel reactorPreparation before operation: equipment inspection and raw material pretreatment
Equipment inspection
Component integrity: Check the integrity of the reactor body, pipelines, valves, sensors (temperature, pressure, flow), and sealing components to ensure that there is no risk of leakage.
Connection firmness: Confirm the stability of the connection between the microchannel and the fluid transport system, as well as the light source (if involved in photochemical reactions), to avoid fluid leakage or uneven lighting caused by looseness during the reaction.
Cleaning and disinfection: Use mild cleaning agents and a soft cloth to wipe the surface of the reactor, avoiding corrosive cleaning agents; Professional cleaning solutions and devices are used internally to remove residues, preventing blockages or cross contamination.
Raw material pretreatment
Filtration and purification: The reactants are filtered, distilled, or dissolved to remove solid particles, moisture, or impurities and prevent microchannel blockage.
Proportioning and dilution: Adjust the raw material concentration according to the reaction requirements (such as diluting 40% formaldehyde to 16% -20%) to ensure the stability of the reaction system.
2、 Feeding operation: precise control of flow rate and speed
Solvent transfer pump setting
Connecting pipeline: Fix the inlet and outlet pipes of the pump body to ensure sealing.
Flow regulation: After connecting the power, adjust the feed flow rate to the specified reading (such as the ratio of formaldehyde to air feed 1:4.45), and start the pump to start feeding.
Rate control: The feed rate should be stable and not too fast to avoid reactant accumulation or uncontrolled reaction in the microchannel.
Raw material tank preparation
Liquid level management: Add material to the raw material tank to 2/3-3/4 of the tank volume to prevent the pump from running idle due to low liquid level or overflowing due to high liquid level.
3、 Reaction control: coordinated regulation of temperature, pressure, and flow rate
temperature control
High temperature cycler operation: Connect the inlet and outlet of the heat exchange medium (such as heat transfer oil and water), pour in the medium and adjust the heating temperature to the set value (such as 110-115 ℃ in zone I and 125-130 ℃ in zone II of acetic acid synthesis), and start heating and circulation.
Real time feedback adjustment: For temperature sensitive reactions, a temperature feedback control system (such as PLC+PC intelligent control) is used to automatically adjust the heating power or cooling water flow rate, ensuring that temperature fluctuations are within the allowable range (such as ± 1 ℃).
Pressure and flow rate monitoring
Pressure sensor: Real time monitoring of reaction system pressure (such as controlling pressure of 0.6-1.2MPa in acetic acid synthesis) to prevent safety accidents caused by overpressure.
Flow sensor: monitors the flow rate of reactants to ensure that they enter the reactor at a predetermined ratio and rate (such as air and formaldehyde residence time of 1.5-2.0 seconds), ensuring reaction selectivity.
Mixing and Mixing
Magnetic/mechanical stirring: By adjusting the stirring speed and time, the reactants can be fully mixed (such as high-pressure air nozzle design in gas-liquid reactions, which can enhance the mixing effect).
4、 Reaction termination and product processing
Termination condition judgment
Time/degree control: According to the reaction kinetics, terminate the reaction at a predetermined time (such as a total residence time of about 5 seconds in glyoxylate synthesis) or after the conversion rate meets the standard.
Cooling/Terminating Agent: Stop the reaction by lowering the temperature (such as in microchannel heat exchangers) or adding a terminating agent (such as an acidic solution).
Product separation and purification
Pressure reduction and cooling: After the reaction is completed, the pressure is reduced through a back pressure connecting tube and cooled through a microchannel heat exchanger (such as reducing to atmospheric pressure in the synthesis of acetic acid).
Gas liquid separation: Use a gas-liquid separator (with a built-in liquid blocking grid layer) to separate the tail gas from the crude product (such as acetic acid crude product with a water content of 55% -60%).
Purification process: Further purification is carried out through distillation, extraction, or microporous membrane filtration (precision 0.10-1.0nm) to obtain high-purity products (such as crystalline acetic acid).
5、 Cleaning and Maintenance: The Key to Extending Equipment Life
Instant cleaning
Residual removal: Immediately rinse the interior of the microchannel with professional cleaning solution after the reaction is complete to prevent solid deposition or corrosion (such as removing catalyst residue after acetic acid synthesis).
High pressure water flushing: Use high-pressure water to flush stubborn residues to ensure smooth passage.
Deep disinfection and drying
Oven treatment: Place the reactor in an oven (such as 80-100 ℃) for disinfection and drying to avoid microbial growth or residual moisture.
Lubrication maintenance: Regularly add lubricating oil to frequently moving parts such as pistons and valves to reduce wear and tear.
Regular inspection and replacement
Vulnerable parts management: Check sealing components, O-rings and other vulnerable parts every 3-6 months, and replace them in a timely manner to maintain sealing performance.
Sensor calibration: Use standard substances (such as pure metals) to calibrate temperature sensors to ensure data accuracy.
VIMicrochannel reactorSafety precautions: Prevention is better than remediation
Personal protection: Wear lab coats, gloves, and goggles during operation to prevent chemical splashing.
Emergency facilities: Ensure that there are emergency flushing devices and first aid equipment in the laboratory, and be familiar with their usage.
Ventilation environment: Maintain good ventilation to reduce the impact of external temperature and humidity changes on the reactor.
Compliance operation: Strictly follow the equipment manual and safety regulations to avoid accidents caused by illegal operations.