What should be noted when using a laboratory distillation tower

Safety, patience, and meticulousness are the key to operating a laboratory distillation tower. Strictly adhere to the basic principles of "installation, leak detection, slow heating, monitoring, and sequential shutdown". The key points to note when using a laboratory distillation tower can be divided into several stages:
1、 Preparation and inspection before operation
This is the most critical step in ensuring safety and cannot be omitted.
Equipment installation and air tightness inspection:
Correct assembly: Strictly assemble the tower body, condenser, receiving bottle, vacuum joint, etc. according to the instructions or training received. Each interface should be aligned and subjected to uniform force, especially for glass components. When tightening the clamps, the force should be moderate to prevent cracking due to uneven stress.
Airtightness testing (crucial): Distillation, especially vacuum distillation, requires system sealing.
Close all valves, start the vacuum pump, and evacuate the system to a certain degree of vacuum.
Close the valve between the system and the vacuum pump, and observe whether the vacuum level remains stable in a short period of time. If the pressure rises rapidly, it indicates that there is a leakage point, and it is necessary to use soap water and other methods to investigate one by one (interfaces, valves, plugs, etc.) until the problem is solved. Heating operations are strictly prohibited if the airtightness is not qualified.

Material addition and system smoothness:
Material properties: Clarify the properties of the material to be separated, such as boiling point, thermal sensitivity, oxidation, corrosiveness, flammability and explosiveness. This is related to the choice of heating method, temperature, and vacuum degree.
Feeding: Add materials through the feeding port, taking care not to exceed the safe capacity of the tower kettle (usually 2/3 of the capacity), to prevent liquid from flushing during boiling.
Add packing: If it is a packing tower, ensure that the packing is clean and evenly filled to avoid dry areas.
Check for smoothness: Ensure that all channels such as the overhead distillate pipeline and vacuum pipeline are unobstructed.

2、 During the operation process
1. Heating control:
Slow heating: It is strictly prohibited to suddenly apply full power heating! The heating power should be slowly and gradually increased. Excessive heating can cause liquid flooding, where rising steam inside the tower carries a large amount of liquid to the top of the tower, disrupting the distillation process and even causing accidents.
Choose a suitable heat source: According to the document, heating methods include electric heating sleeves, thermal oil baths, etc. Ensure that the upper temperature limit and temperature control accuracy of the heat source meet the requirements. For thermosensitive materials, it is necessary to strictly control the temperature of the tower kettle.
Establish and maintain balance:
Full reflux: After heating begins, do not remove the product and allow all the condensed liquid at the top of the tower to reflux back into the tower (full reflux operation). Continue for a period of time to bring the gas and liquid phases of each tray or packing section in the tower to equilibrium (temperature readings tend to stabilize). This is a prerequisite for achieving good separation efficiency.
Adjust reflux ratio: After establishing equilibrium, set the reflux ratio as needed. The larger the reflux ratio, the better the separation effect, but the slower the output rate. Optimization should be carried out based on product purity and efficiency requirements.

2. Vacuum operation:
If vacuum distillation is carried out, the order must be followed: first evacuate, then heat. The order of shutdown is reversed: first stop heating, wait for the material to cool to a safe temperature, then turn off the vacuum pump, and finally slowly introduce air into the system. Reversing the order can cause boiling liquids to suddenly boil violently due to external pressure, which is extremely dangerous!
Install a cold trap between the vacuum pump and the front stage to capture low boiling point solvents and protect the vacuum pump.

3. Real time monitoring:
Closely observe the temperature readings of the tower kettle, tower body, and tower top, and record the pressure values.
Observe the gas-liquid contact inside the tower, promptly detect and handle abnormal phenomena such as "liquid overflow" or "leakage" (liquid overflow is manifested as the liquid inside the tower being held up by steam and unable to go down, resulting in increased pressure fluctuations).
It is strictly prohibited to leave the post, and someone must be present to guard during the operation.

3、 After the operation is completed
Shutdown in sequence:
Stop heating ->wait for the system to cool naturally ->release the vacuum (slowly empty) ->turn off the cooling water.
Be sure to wait for the temperature of the tower kettle to drop below the flash point or boiling point of the material before disassembling.

System cleaning and maintenance:
After the equipment cools down, disassemble and clean it in a timely manner. Prevent residual materials from corroding equipment or affecting the next experiment.
For stainless steel towers, it is important to choose appropriate cleaning agents to avoid corrosion. For glass towers, handle them gently and store them properly.

4、 Special precautions
Customization feature: The document clearly states that "the above parameters are not used as ordering standards", which means that your device may have its specific configuration. Be sure to familiarize yourself with the specific operation manual of your device and the mutually confirmed plan.

Material compatibility: Confirm whether your material is compatible with the material in contact with the equipment (high borosilicate glass 3.3 or SUS304 stainless steel) to avoid corrosion. For example, concentrated hot phosphoric acid, strong alkali, etc. can corrode glass.

Electrical safety: Pay attention to the power specifications (220V/380V), ensure good grounding, and prevent electric shock.

Heat medium selection: If using heat transfer oil or high-temperature circulators, ensure that the thermal stability temperature of the heat medium is higher than the operating temperature to prevent decomposition, coking, and even combustion of the heat medium.