1、 Decreased evaporation efficiency
1. Heating tube blockage or scaling
Phenomenon: The evaporation rate significantly decreases (such as the production capacity dropping from 40 tons/day to 20 tons/day), the temperature of the first effect rises abnormally (such as reaching 94 ℃), and the temperature of the second effect rises synchronously.
Reason: Long term operation leads to the deposition of scale, material residue, or organic crystals on the inner wall of the tube.
Solution:
Physical cleaning: Rinse the pipes with a high-pressure water gun every week to remove blockages;
Chemical cleaning: Use a 5% citric acid solution to circulate and dissolve calcium and magnesium scale, or rinse organic residues with acetone.
2. Insufficient steam utilization rate
Phenomenon: Increased energy consumption and abnormal proportion of secondary effect evaporation (normally around 35%).
Reason: The mixed steam temperature of the heat pump is unbalanced (normally around 90 ℃) or the heating area design is not matched.
Solution:
Calibrate the intake ratio of the heat pump to ensure that the mixed steam temperature is ≤ 90 ℃;
Check the area configuration of the heater and expand it if necessary.
2、 Abnormal vacuum degree
1. Insufficient vacuum degree (>-0.07MPa)
Phenomenon: The boiling point of the material increases, and the concentration efficiency decreases.
Reason:
Leakage: The flange and manhole sealing ring are aging or not tightened;
Vacuum pump malfunction: insufficient/contaminated pump oil, worn blades, or blocked pipelines.
Solution:
Apply soap bubbles to the interface to detect leaks and replace the fluororubber sealing ring;
Supplement/replace the dedicated vacuum pump oil and clean the crystal residue inside the pump.
2. Large vacuum fluctuations
Reason: The cooling water temperature is too high (>32 ℃) or the flow rate is insufficient, resulting in insufficient condensation.
Solution:
Check the set temperature of the freezer (≤ 5 ℃) to ensure that the cooling water circulation rate is ≥ 35t/h;
Clean the surface scale of the condenser to improve water quality.
3、 Temperature control malfunction
1. One effect temperature exceeds the standard (>90 ℃)
Reason: Failure of temperature control sensor or high steam pressure (normal ≤ 0.25MPa).
Solution:
Calibrate the temperature sensor and replace the damaged probe;
Adjust the steam pressure reducing valve to stabilize the pressure at 0.2-0.3MPa.
2. Abnormal second effect temperature (deviation from 60-65 ℃)
Reason: Unstable vacuum degree or poor circulation in the heating chamber.
Solution:
Optimize the sealing performance of the vacuum system;
Check the material flow rate in the heating chamber to avoid local overheating.
4、 Condensation system malfunction
1. Low solvent recovery rate
Reason: Condenser scaling or internal pipeline leakage.
Solution:
Disassemble the condenser and clean the crystals with ethanol ultrasonic cleaning;
Replace the cracked condenser pipeline.
2. Foam Spill
Reason: Sudden vacuum drop or materials containing saponins that are prone to foaming.
Solution:
Add defoamer;
Adjust the synergistic parameters of vacuum and heating (such as heating first and then vacuuming).
5、 Mechanical component damage
1. Wear of shaft seal
Phenomenon: Leakage of slurry at the shaft seal, accompanied by abnormal noise.
Solution:
Use wear-resistant materials (such as H500 self-lubricating repair agent) for on-site scraping and repairing;
Regularly add high-temperature lubricating grease.
2. Mixing blade malfunction
Reason: Reverse operation or bearing oil shortage.
Solution:
Confirm that the motor direction is clockwise;
Supplement lubricating grease and replace damaged bearings every month.
6、 Preventive maintenance recommendations
1. Daily management:
Steam with clean water for 30 minutes after each shutdown to prevent residue from solidifying;
Verify the vacuum gauge and thermometer weekly to ensure accurate readings.
2. Regular maintenance:
Disassemble and wash the heating tube and condenser every quarter;
Replace all seals and inspect the vacuum pump annually.
System maintenance can reduce 80% of failures and extend equipment lifespan by 3-5 years.