油水分离器2详解.ppt

MARPOL Pollution Prevention Oily Water Separator Bilge Systems Bilge Systems The essential purpose of a bilge system, is to clear water from the ships dry compartments, in emergency. The major uses of the system, are for clearing water and oil which accumulates in machinery space bilges as the result of leakage or draining, and when washing down dry cargo holds. The bilge main in the engine room, has connections from dry cargo holds, tunnel and machinery spaces. International Legislation Oil/water separators are necessary aboard vessels to prevent the discharge of oil overboard mainly when pumping out bilges. The requirement to fit such devices is the result of international legislation. Legislation was needed because free oil and oily emulsions discharged in a waterway can interfere with natural processes such as photosynthesis and re-aeration, and induce the destruction of the algae and plankton so essential to fish life. Oil Density It is important that an oil/water separator is correctly installed, used and maintained. It is generally accepted that oil is less dense than water and this is the basis of the design of devices to separate the two liquids. Some of the modern heavy fuels however, have a density at 15℃ which approaches, is the same as or is even higher than that of water and this has added to the problems of separation in oil/water separators and in centrifuges. Two Separating Ways The operation of oil/water separators relies heavily on gravity and a conventional difference in densities. Centrifuges by their speed of rotation, exert a force many times that of gravitational effect and the heater reduces density in comparison with that of water. Oil/Water Separation Oil/water separators and centrifuges are both employed for the purpose of separating oil and water but there are major differences. Oil/water separators are required to handle large quantities of water from which usually, small amounts of oil must be removed. Various featur