Oily water seperator | Bilge water seperator | Oil and water Seperator

Summary

The script details the operation of an oily water separator designed to achieve a 15 ppm oil content in the discharge. It operates in two stages: gravity separation in the first and coalescing filters in the second. The bilge pump supplies water, which is cleaned by passing through baffles and coalescing filters, removing oil and solids. An automatic drainage system and a capacitance probe monitor oil levels, ensuring compliance with environmental standards. An alarm system and a three-way valve prevent overboard discharge if oil levels exceed limits. The separator also includes safety features like relief valves to prevent overpressure and accidental discharge.

Takeaways

• 🔬 The oily water separator operates in two stages: gravity separation and coalescing filter separation.
• 💧 The bilge pump delivers clean sea water to the separator, and air is removed until water issues out.
• 📉 Oil separates by gravity in the first stage and collects at the top, while water passes through to the second stage.
• 🚰 A capacitance probe senses the oil quantity in the collection space and controls the oil drain valve.
• 🔧 The oil drain valve is a diaphragm-controlled piston valve, operated by control air through a solenoid valve.
• 🌊 Water from the first stage passes to the second stage through a central pipe and is filtered by coalescing filters.
• 🛑 If the oil content in the final discharge exceeds 15 ppm, an alarm is triggered, and the discharge is redirected to the bilge tank.
• 🔄 The separator reverts to normal operation once the oil content drops below 15 ppm.
• ⚙️ A relief valve is essential to prevent overpressure and accidental discharge under all working conditions.
• 📊 The usual working pressure for the separator is around two bar, with the relief valve set at approximately two and a half bar.

Q & A

What is the purpose of an oily water separator?

An oily water separator is used to separate oil from water, ensuring that the water discharged is clean and meets environmental regulations, such as maintaining an oil content below 15 ppm.

How many stages are involved in the separation process of an oily water separator?

The separation process in an oily water separator occurs in two stages: the first stage uses gravity for separation, and the second stage uses coalescing filters.

What is the role of the bilge pump in the oily water separator system?

The bilge pump delivers clean seawater to the first stage of the oily water separator through the inlet valve.

Why is the vent kept open until all the air is removed from the separator?

The vent is kept open to ensure that all air is removed from the separator, allowing for proper water flow and separation process to occur.

How does oil separate by gravity in the first stage of the separator?

As water enters through the inlet valve, oil separates by gravity and collects at the top of the separator due to its lower density compared to water.

What is the function of the baffle plates in the separator?

The baffle plates in the separator help to guide the water flow and allow oil droplets to stick to them, facilitating the separation process.

How is oil automatically drained from the top of the first stage separator?

Oil is automatically drained to the oil tank when the level reaches the bottom of the sensor, which triggers the oil drain valve from the top of the first stage separator.

What type of valve controls the oil drain from the first stage separator?

A diaphragm-controlled piston valve is used to control the oil drain from the first stage separator, with control air supplied through a solenoid-operated pilot valve.

What is the purpose of the capacitance probe in the oily water separator?

The capacitance probe senses the oil quantity in the collection space and energizes the solenoid through the control switch, helping to regulate the oil drainage.

How does the coalescing filter work in the second stage of the separator?

The coalescing filters in the second stage remove the remaining oil in the form of small droplets, which coalesce to form larger drops that rise to the oil collecting space.

What happens if the oil content of the final discharge is more than 15 ppm?

If the oil content exceeds 15 ppm, the monitor senses this and triggers an audible and visual alarm in the engine room, and also sends a signal to a three-way valve to redirect the discharge to the bilge tank instead of overboard.

Why is a relief valve essential on the shell or incoming mixture line of the oily water separator?

A relief valve is essential to prevent overpressure and accidental discharge to a confined space or overboard, ensuring safe operation under all working conditions.

What is the usual working pressure for an oily water separator?

The usual working pressure for an oily water separator is around two bar, which is the setting for the spring-loaded water discharge valve, with the relief valve set at approximately two and a half bar.