Question 48 1AE01 - First Assistant Engineer

The Correct Answer is D **Explanation for Option D (Correct Answer):** The component labeled "A" is positioned within the main body of the separator vessel, typically near the mid-to-upper section. The primary function of a probe in this location within an Oily Water Separator (OWS) is to distinguish between the two separated liquids: the lighter oil accumulated at the top and the heavier water below. Therefore, component A is the **oil/water interface level sensing probe**. This probe is crucial for the automated operation of the OWS, as it signals the control system when enough oil has accumulated to warrant opening the oil discharge valve. **Explanation of Incorrect Options:** * **A) oil content monitor probe:** This probe is part of the Oil Content Monitoring (OCM) unit, which measures the parts per million (ppm) of oil in the *effluent water* after it has left the separator and filtering stages. It is located downstream, not usually mounted directly inside the main separation vessel to sense the interface. * **B) separator vessel pressure relief valve:** A pressure relief valve is a safety device mounted externally, typically on the top flange of the vessel, to prevent over-pressurization. It does not penetrate the vessel wall to sense liquid levels or interfaces. * **C) separator vessel vacuum breaker:** A vacuum breaker is also a safety device, usually located at the very top of the vessel, designed to prevent the vessel from collapsing due to internal vacuum. It is not used for monitoring liquid levels or interfaces.