Oilers/Plant Tenders (HHC) Civil Service Practice Exam

What is a notable characteristic of oils used in steam turbines?

1. Low demulsibility

2. They are unrefined

3. They have high demulsibility

4. High viscosity

The correct answer is: They have high demulsibility

The correct choice is that oils used in steam turbines have high demulsibility. High demulsibility is an important characteristic because it indicates that the oil can effectively separate from water. This property is crucial in steam turbine applications, where the presence of water can lead to emulsions that compromise the oil's lubricating properties, potentially causing equipment failure or reduced efficiency. Oils with high demulsibility help to ensure that water does not remain in the oil, allowing for better lubrication and protecting metal surfaces from corrosion. Furthermore, this quality helps maintain the oil's performance over time, especially in systems subjected to varying temperatures and pressures, which are common in steam turbines. In contrast, oils with low demulsibility would struggle to separate from any water present, leading to emulsified oil that could harm the system. Unrefined oils and those with high viscosity do not align with the specific performance needs of steam turbines, where refined oils and optimal viscosity are required to minimize wear and ensure efficient operation.