Maintenance method and troubleshooting of crude oil boiling point distiller

Common troubleshooting and repair methods for crude oil boiling point distiller

1、 Heating system malfunction (distillation power core)

1. No heating

• Common causesHeating wire/heating rod breakage, short circuit, relay burnout, fuse blown, no output from temperature control module.

• Repair steps

1. After power failure, use a multimeter to check the resistance of the heating element. If it shows infinity, replace the heating wire/rod with the same specification directly.

2. Check the fuse inside the control box. If it is blown, replace it with a fuse that matches the rated current; Observe the relay contacts. If they turn black or adhere, replace the relay and polish the wiring terminals.

3. Test the output voltage of the temperature control module. If there is no voltage output, check whether the wiring of the temperature control board is loose. If it is loose, tighten it. If the fault is not resolved, replace the temperature control board.

• preventive measuresCheck the status of heating elements monthly to avoid dry burning; Install overcurrent protection devices to prevent frequent start stop damage to components.

2. Heating out of control and temperature exceeding the set value

• Common causesThe PID parameters of the thermostat are out of order, the relay is stuck, and the temperature sensor is malfunctioning without feedback.

• Repair steps

1. Restore the factory parameters of the thermostat, recalibrate the PID parameters (reduce the proportional band, adjust the integration time), and lock the parameters after calibration to prevent accidental changes.

2. After power failure, disassemble the relay and manually test the continuity of the contacts. If there is adhesion, immediately replace the high-temperature and high current resistant relay.

3. Calibrate the sensor with a standard thermometer. If the deviation exceeds ± 1 ℃, replace the Pt100 or thermocouple sensor.

• preventive measuresCalibrate the temperature control system quarterly; Confirm that the insertion depth of the sensor meets the standard before the experiment (it needs to be placed at the steam center of the distillation flask branch).

3. Uneven heating and slow heating rate

• Common causesLocalized damage to the heating element, unstable voltage, coking of the heating furnace, or damage to the insulation layer.

• Repair steps

1. Check the local resistance of the heating element. If there is a difference in segmented resistance values, replace the entire heating element group (it is not recommended to replace local elements separately).

2. Install a voltage regulator power supply and check for poor contact in the laboratory power supply circuit.

3. Clean the coking material on the inner wall of the heating furnace with a scraper, and refill the damaged insulation layer with high-temperature resistant insulation cotton.

2、 Vacuum system malfunction (key to vacuum distillation)

1. The vacuum degree cannot reach the set value

• Common causesLeakage of joints/grinding ports, cracks in glass components, deterioration and emulsification of vacuum pump oil, wear of vacuum pump blades, and blockage of pipelines.

• Repair steps

1. Leak detection priorityRe apply high vacuum silicone grease to all grinding edges and joints, and tighten the clamps; Use a helium leak detector to detect small leaks, and reseal the welding area if there is a leak.

2. Check if there are cracks in the glass distillation flask, capillary tube, and sand core filter. If they are damaged, replace them immediately (to avoid explosion under negative pressure).

3. Observe the condition of the vacuum pump oil. If it is cloudy and emulsified, empty the old oil, add specialized vacuum pump oil, and clean the impurities inside the pump; If the oil level is below the scale line, it needs to be replenished to the standard position.

4. If the pump body noise is high and the vacuum degree remains low, it is due to blade wear or pump body seal failure. It is necessary to contact the manufacturer for professional repair or replacement of the vacuum pump.

5. Disassemble the vacuum pipeline, rinse the filter with organic solvent, and unclog the clogged capillary tube.

• preventive measuresApply vacuum grease for leak detection before each experiment; Replace the vacuum pump oil every month and install an oil-gas separator.

2. Severe fluctuations in vacuum degree

• Common causesSystem micro leakage, sample boiling and flushing, vacuum valve leakage.

• Repair steps

1. During the experiment, avoid touching the vacuum joint and apply soap solution to the suspected leak point. The bubbling area is the leak point and should be repaired.

2. Reduce the heating rate and add zeolite or capillary tube to the distillation flask. The sample needs to be pre treated to remove water and low boiling substances to prevent contamination of the vacuum system by boiling.

3. Disassemble the vacuum valve, replace the valve core sealing ring, and regularly lubricate the valve to ensure smooth opening and closing.

3、 Temperature control system malfunction (precise temperature control core)

1. Large temperature display deviation (high/low)

• Common causesSensor aging drift, incorrect installation position, environmental heat source interference.

• Repair steps

1. Verify the sensor with a standard mercury thermometer or calibrator, and replace it if the deviation exceeds the limit.

2. Adjust the insertion position of the sensor to ensure that the probe is aligned with the steam channel of the distillation flask branch pipe, and the insertion depth is strictly in accordance with the instrument manual.

3. Remove the heat source around the instrument (such as oven, electric furnace), clean the temperature controller cooling fan, and ensure ventilation and heat dissipation.

2. Temperature fluctuations and drastic changes

• Common causesLoose wiring, signal interference, and improper PID parameters.

• Repair steps

1. Tighten the sensor wiring terminals, replace the shielded wires to reduce electromagnetic interference, and keep the wiring away from power cables.

2. Contact professional engineers to optimize PID parameters (reducing the proportional band can accelerate response, adjusting the integration time can reduce fluctuations). Non professionals are prohibited from making arbitrary modifications.

4、 Condensation system malfunction (critical for fraction recovery)

1. The distillate does not condense and the steam escapes

• Common causesInsufficient cooling water flow, clogged and scaled condenser tubes, excessively high cooling water temperature, and damaged condenser tubes.

• Repair steps

1. Check the operation status of the cooling water pump, clean the inlet filter, and ensure that the cooling water flow rate is ≥ the rated value of the instrument; In summer, a chiller should be equipped to control the inlet water temperature to ≤ 30 ℃.

2. Rinse the condenser tube with organic solvents such as acetone and ethanol. For stubborn scaling, soak it and rinse it (strong acid should be used with caution for glass condenser tubes), then gently unclog it with a soft strip.

3. Perform pressure leak detection on the condenser tube, and replace it with a condenser tube of the same specification if it is damaged or leaks.

2. Unstable droplet velocity and severe reflux of condensate

• Common causesFluctuations in heating rate and localized blockage of condenser tubes.

• Repair steps

1. Switch to closed-loop temperature control mode and set a uniform heating program to avoid unstable steam flow caused by manual adjustment of heating power.

2. Clean the condenser tubes in sections, with a focus on clearing the areas of local fouling to ensure even cooling.

5、 Fractional receiving system malfunction (key to precise cutting)

1. Inaccurate receipt and incorrect cutting of fractions

• Common causesMalfunction of liquid level sensor, misalignment of receiving bottle, and cross contamination of residual oil in the pipeline.

• Repair steps

1. Clean the liquid level sensor probe, calibrate the measuring system with a standard volumetric flask, and replace the sensor if the deviation is too large.

2. Adjust the positioning device of the receiving bottle, check the sealing condition of the switching valve, and replace the aging sealing ring to prevent leakage.

3. Before cutting different fractions, rinse the receiving pipeline with solvent to prevent residual oil from mixing into the next component.

2. Receive liquid droplet leakage

• Common causesPoor sealing of the grinding mouth, cracks in the receiving bottle, and damaged valves.

• Repair steps

1. Apply sealing grease again and tighten the grinding joint; Check for cracks in the receiving bottle, replace if damaged.

2. Repair or replace damaged receiving valves, and regularly lubricate valve components.

6、 General fault handling and safety precautions

1. Emergency shutdown scenarioWhen there is a vacuum leak, temperature loss of control, or glass breakage, the power and vacuum source should be immediately cut off, and the system should be cooled down and the vacuum broken before handling to prevent material flushing, explosion, or personnel burns.

2. Daily maintenance core

• After the experiment, all glass components, pipelines, and condenser tubes must be cleaned to avoid residual oil solidification and blockage.

• Replace vulnerable parts such as system seals and vacuum grease every six months.

• Regularly verify the safety protection devices (over temperature and over pressure alarms) to ensure their normal triggering.