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1、Jimei university,Lesson 22,OIL POLLUTION PREVENTION (防止油污染),Jimei university,There are three major sources of oil pollution from the operation of ships: 1. the discharge into the sea of tank washings from tankers(油轮);,Jimei university,2. the ballast carried in oil cargo and bunker tanks and 3. the d
2、ischarge from machinery space bilges.,Jimei university,To prevent pollution by oil from ships, the IMO has published Regulations(规则, 规章) for the Prevention of Pollution by Oil,Jimei university,(MARPOL 73/78) that came into force(开始有效, 开始实行) in December 1983.,Jimei university,The first source is redu
3、ced by the discharge of tank washings to a slop tank(污水舱) for settling,Jimei university,and discharge overboard of the water while retaining the load on top for pumping ashore to the refinery (炼油厂).,Jimei university,Crude Oil Washing (COW) eliminates the use of water and enables cargo residues(残余,剩余
4、物) to be pumped ashore during cargo discharge because,Jimei university,because cleaning is carried out simultaneously(同时地) with the discharge.,Jimei university,As well as requiring tankers of certain sizes to have segregated(隔离) or clean ballast tanks (SBT or CBT) to reduce the ballast contaminated(
5、污染) with oil,Jimei university,new regulations have strict requirements for control of discharge of oil from a tanker.,Jimei university,In brief, if oil cargo residue is to be discharged from a tanker it must: a) not be in a Special Area; b) be farther than 50 nautical miles(海里) from land;,Jimei univ
6、ersity,c) be on passage. Additionally; d) the instantaneous(瞬间的) rate of discharge must not be more than 30 litres per mile; e) the total amount must be not more than 1/30,000 of the particular cargo, and,Jimei university,f) the oil discharge monitoring and control system and slop tank arrangement r
7、equired must be in operation,Jimei university,Engine room bilge disposal(处理) is treated separately in the regulations from discharges related to cargo/ballast operation.,Jimei university,In general, ships over 400 gt are permitted to discharge machinery space bilges into the sea provide:,Jimei unive
8、rsity,a) the oil in the bilge discharge without dilution(稀释) does not amount to more than 15 ppm;,Jimei university,b) this is achieved by the operation of an oily water separator and/or filtering system with discharge monitoring and control;,Jimei university,c) the ship is moving on passage; d) it i
9、s at least 12 nautical miles from land, and e) is not within a Special Area.,Jimei university,A tank or tanks of adequate capacity, having regard to(without regard to) the type of machinery and length of voyage, should be provided on board to receive the oil residues (sludge),Jimei university,such a
10、s those resulting from the purification (purifier/clarifier) of fuel and lubricating oils and oil leakage in the machinery spaces.,Jimei university,The operations related to cargo oil, oil residue, oil and fuel tank ballast and washing, and bilge must be filled in the Oil Record Book.,Jimei universi
11、ty,The Oil Record Book (part one) for machinery space operations is the responsibility of the engine room department.,Jimei university,All constructions and equipment for oil pollution prevention must be proved in accordance with the regulations,Jimei university,and issued with International Oil Pol
12、lution Prevention (IOPP) certificates.,Jimei university,OILY WATER SEPARATORS,Oily water separators are used to ensure that ships do not discharge oil when pumping out bilge water, or oily water from oil tanks or any oil contaminated(污染) space.,Jimei university,According to international legislation
13、s(国际法规MARPOL 73/78 (International convention for the prevention of pollution from ships) related to oil pollution,Jimei university,depending upon the size of a ship a discharge purity of 100 or 15 parts per million (p.p.m)(百万分之) of oil will be required.,Jimei university,Oily water separators using t
14、he gravity system can only achieve 100 ppm and,Jimei university,and must therefore be used in conjunction with some form of filter to discharge clean water with less than 15 ppm of oil.,Jimei university,15,9oil collection space,22coarse separating compartment,23fine separating compartment,100ppm,Coa
15、lescerinserts,24 catch plate,15ppm,Jimei university,A complete oil/water separator and filter unit is first filled with clean water;,Jimei university,the oily water mixture is then pumped through the separator inlet pipe into the coarse(粗（糙）的) separating compartment.,Jimei university,Here some oil,
16、as a result of its lower density, will separate and rise into the oil collection space.,Jimei university,The remaining oil/water mixture now flows down into the fine separating compartment and moves slowly between the catch plates(捕集板).,Jimei university,More oil will separate out onto the underside of these plates and travel outwards until it is free to rise into the oil collecting space.,Jimei university,The almost oil-free water passes into the central pipe and leaves the separator unit. The purity at this point will be 100 p.p.m. or less.,
