Sea Water Desalination
Storing large quantities of fresh water not only expensive but also takes up a large amount of space. Desalination is based on the evaporation principle: sea water which has been filtered through a coarse mesh is evaporated in a heat exchanger plate stack made of titanium to precipitate salt and impurities. A further plate stack condenses the steam into drinking water. A salt measuring cell now checks residual salt content which is usually below 4 ppm. If a value below this is reliably maintained, the fresh water can be passed into a storage tank and subjected to further treatment in the form of UV sterilization. A re-hardening filter then finally returns enough hardness to the fully demineralized water to make it potable for humans.
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Answer the following questions: 1. What is bilgewater/sludge? 2. How is the bilgewater treated? 3. What is the way of sludge treatment? 4. How can the sludge be disposed? 5. Describe the process of desalination. |
Vocabulary
Alkalinity is the alkali concentration or alkaline quality of a substance that contains alkali.
The ash content is related to the amount of inorganic material in the fuel.
The carbon residue of a fuel is the tendency to form carbon deposits under high temperature condition in an inert atmosphere, and may be expressed as either Conradson Carbon Residue (CCR) or Micro Carbon Residue (MCR). The maximum limit of carbon residue content in fuel is 22 %.
Detergent is a synthetic cleaning agent or substance.
Density is the relationship between mass and volume at a stated temperature.
The flash point of the liquid is the lowest temperature at which sufficient vapor is given to produce a flash on application of a flame under specified test conditions.
Oiliness is the oil’s ability to adhere to the surfaces such as white metal bearings.
Oil additives are chemical compounds that improve the lubricant performance of base oil. The manufacturer of many different oils can utilize the same base stock for each formulation and can choose different additives for each specific application. Additives comprise up to 5% by weight of some oils.
The pour point is the lowest temperature at which a marine fuel oil can be handled without excessive amounts of wax crystals forming out of solution. At a lower temperature the fuel will gel, thereby preventing flow.
The specific gravity of HFO is its ratio to the density of water at a specified temperature. Bunker oil HFO ranges between 0.95-1.03
Viscosity is a measurement of the resistant of a liquid to shear or flow and is measured in Centistokes (CST) with a quoted reference temperature.
Volatility is the ability of the oil to ignite due to a low flash point.