Summary of reasons for large temperature difference between upper and lower cylinders

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Summary of reasons for large temperature differences between the upper and lower cylinders. During my involvement in the commissioning of small-scale power units, I identified the following reasons for such large temperature differences: 1. Poor drainage before and during startup. The hydrophobic pipe is too small (〈DN25). After startup, the main steam drain should be reduced to prevent low drain pressure in the cylinder, which would hinder proper drainage. The hydrophobic expansion tank should be at least 1 meter above the highest water level of the condenser. 2. The lower cylinder has poor insulation; the wind shields are not secure, and the insulation bricks have fallen off. 3. Poor contact of the thermocouples, especially in the lower cylinder, as well as inadequate insulation around the thermocouples. 4. The steam supply time for the shaft seal is too long. 5 The vacuum level should be maintained at 55–60 KPa. 6. Starting by engaging the low-temperature heater first can reduce the temperature difference. 7. Improper sequence of steam valve adjustment results in partial steam admission.