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OIL TANKER FAMILIARIZATION COURSE

OIL TANKER FAMILIARIZATION COURSEINDEX CHAPTER 1. 2. 3. 4. 5. 6. SUBJECT INTRODUCTION HYDROCARBON STRUCTURE TANK ARRANGEMENTS OPERATIONS MARINE POLLUTION SAFETY ON OIL TANKERS PAGE NO. 1-13 14-19 20-23 34-53 54-59 60-84

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CHAPTER 1INTRODUCTION 1.1.0 ) HISTORY & DEVELOPEMNT:

In the industrial economy of the modern world, in which the oil economy plays a major role, in tankers which are the main means of oil transportation and have attained an important place in the international business, and global trade. In the context of the above, tankers demand specialized knowledge, training and techniques both in their design, construction and the personnel who are responsible to manage them on board at sea. The history of oil exploration dates back to 1859 when the first oil well was sunk in Pennsylvania, which was followed by the production of oil on 27th of Aug. 1859. Since then the production of oil has achieved phenomenal rise as far as its exploration and production is concerned. The increased industrialization in the recent past, led to the increased demand of oil and hence tremendous increase of oil production and transportation. ELIZABETH WATTS a wooden sailing ship was the first transported cargo of oil of England forms the U.S. in 1861. The oil was carried in barrels stowed as general cargo in the ship holds. The development of oil carriers was slow due to the reason that the ship-owners were apprehensive about the leakage of oil form the barrels into the cargo holds which would create dangerous gases in the under deck spaces. There was a heavy demand based on the needs of the newly industrializing economies of the late 19the century for the oil. It needed the transportation of the oil form the oil production countries to the oil consuming countries across the nations and across the sea. Carriage of bulk amount of oil amounted to the requirement of installing of large cylindrical tanks within the holds of the ship which would have involved a great deal of cargo space to be wasted, the iron-hulled ship were developed in the meantime. Several iron-hulled sailing ships were building and used for the trade. Large ironhulled sailing ships fitted with iron tanks and equipped with hand pumps for rapid and safe discharge of cargo came into use of mass scale. ZORASTER was the first ship to use the hull as an oil tank was built. In 1886, the first steamship named GLUCKUF (Good luck) was designed and put into service to carry the petroleum in the bulk amount. It was ordered by a merchant of Hamburg Wilhelm A.Reidmann, to serve the German American Petroleum Company.CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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It was a small ship of 300 ft. long with dwt. of 3020 tons. It served as a prototype of the modern tanker, fitted with steam driven pumps segregated form cargo tanks by steel bulkhead and with the engine room at the other end, separated form the cargo tanks area by cofferdams formed by twin bulkheads. Broadly the pattern of the construction has not been charged since then. The first 20 years of the 20th century seen the tankers getting large in size. The greatest dangers of ship carrying bulk liquids are free surface effect. The movement of ship in a seaway affects the stability of the ship. The engine room aft design awes widely adopted in 1920s. The standard deadweight of tankers was 12000 tons only. 1.2.0) EARLY DESIGN OF BULK OIL CARRIERS: The heavy demand of transportation of petroleum during Second World War far exceeded. The carrying capacity of the ships developed till that time, and called for new standards for bigger and faster ship tankers. As per the need U.S. built 532 tankers of T-2 class, with deadweight of 16750 tons, and with a speed of 14.50 knots. In the post World War II period the area of Middle East developed into a major oil exporter to the industrialized world, hence serving the major source of oil to the world. Suez Canal was the main link between Middle East countries and to the consumers of western world. The limitation of the canal, its width and length dictated the average size of the tanker trading between Middle East load ports and the US and European discharge ports were required to make their passage around the South of Africa. In order to make these passages economically viable larger ships were built and the average size of the tanker was increased to 47000 tons. A modification in the design of the tankers was introduced in 1930. The same design became an accepted norm of the industry in 1950. The summer tanks were eliminated along-with centerline bulkhead. The cargo tanks were further sub-divided transversely into three tanks by installing two longitudinal bulkheads. The free surface in the cargo tanks was just as effectively reduced and the new design allowed greater scope in design and construction of the tankers.

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Any change in the economic as well as political scene in the world has a direct bearing on the economy of the world, which affected the trade as a whole and the tankers trade in particular. The size of the takers increased with each major was the also with the closure of Suez Canal. When the Suez Canal was close for the second time in 1967, it led to the stopping of traffic in the canal and the shortest route of Europe. The resulted in the sudden increase of tanker size to make the transportation of petroleum more economical. The closure provided much impetus to the already booming tankers market and led to the manufacture and utilization of giant size tankers-very large crude carriers (VLCC) and ultra large crude carriers (ULCC). It reached its zenith in 1979, with Sea wise Giant a crude oil carrier of 569,783 tons deadweight. Now days the tankers carry refined oil products and crude oil. The development of petroleum industry laid stress on the use of petroleum products as a cheap & convenient source for manufacture of chemicals. This led to the development of the sophisticated tankers carrying all forms of petroleum products. Petroleum production has numerous by-products, which are of very much utility of the mankind. Some of these are Natural gas and Petroleum gas. In the early stages these by products were considered only as waste and with the development of means of utilize gas as fuel and chemical feedstock, gas recovery plants were used to collect these gases and store them in liquefied form. Today liquefied natural gas and liquefied petroleum gas are important fuels and chemical feedstock. Tankers have been specially designed for their transport. Tankers thus have played a major role in the economy of the modern world, its industrialization, the development of the nations etc. By virtue of carrying so much petroleum products, which the tankers contain, they always pose environmental threats in case of accidental leakage of oil, fire hazards, explosion etc. Strict International regulations have addressed these hazards. The regulatory environment in which the tankers operate are governed SOLAS (1974) and the International Convention of Prevention of Pollution form Ships 1973 and the Protocol of 1978 (MARPOL 73-78) The standards of training for seafarers have had to keep up with the continually changing technology. To ensure uniformity of standards the maritime nation of world covered to adopt the Standards of Training, Certification and Watch keeping for seafarers (STCW 78), which laid down certain minimum standards.

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1.3.0) TYPES OF TANKERS: Oil tankers are divided into six basic types, namely: Crude oil tanker Product tankers Ore oil carriers Ore bulk oil carriers Bitumen carriers Gas carriers

1.3.1) CRUDE OIL TANKERS: They are single decked vessels, with at least two longitudinal bulkheads sub dividing the tanks into smaller tanks transversely. Double bottoms are located under machinery spaces, but not usually elsewhere. A deep tank is nearly always fitted forward of the cargo tanks and this is normally used for carrying bunker oil for the sip. The pump room is usually located aft of the cargo tank system. Slop tanks are provided aft of the cargo tank system. Modern crude tankers are provided with wing thanks for the carriage of water ballast. Crude tankers are large ships. They are employed in transporting crude oil form the oil fields where it is produced to the oil refineries. The crude oil tanker has a relatively simple pipeline system and high capacity cargo pumps to reduce time spent in port of discharge of cargo. The pipeline system does not provide for a high degree of multigrade segregation of cargo. The cargo oil tankers may be provided with heating coils. New crude oil tankers of more than 20,000 tons deadweight and over are provided with an Inert Gas System (IGS) and Crude Oil Washing system (COW). 1.3.2) PRODUCT TANKER; In layout of cargo tank, ballast tanks, slop tanks, pump room, engine room, double bottom tanks etc Product tankers are akin to crude oil tankers. The are generally smaller in size than crude oil tankers. The tank internals are coated to protect against cargo contamination by rust and corrosivity of the cargo attacking the steel of the ship. The cargo tanks are provided with a cargo tank heating systems. They have a large number of small cargo tanks. These ships are provided with elaborate cargo piping system so designed as to enable the simultaneous carriage of more than one product without co-mingling of products during handling and carriage. The product usually carried is Naptha, Motor spirit, kerosene, diesel etc. The cargo pumping system is designed to handle at comparatively lower loading discharging rates. Lower rates are used because some product are extremely volatile, come areCENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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viscous, some are unstable. Product tankers are provided with cargo pumps of lower capacities. A new product tankers of over 0,000 tons deadweight will be provided with an Inert Gas System. 1.3.3) ORE / OIL CARRIER; This is an oil tanker equipped to carry Ore in its center cargo compartments. Compared with similar sized conventional tankers the main difference revolves around the center compartments, which are located over double bottom tanks and have large heavy steel hatch covers. The center compartments so are arranged that the longitudinal plating slope inwards providing a self-stowing factor when loading Ore. The center compartment is generally free from all structural members, which would hinder loading or discharging ore. If coils are required for heating the oil, these are installed in the wings or under the holds and welded on racks to the plating near the bottom. Center compartments contain no piping and are pumped out by wells let into the double bottoms and connected to the cargo piping system through wing tanks. The wing tanks are arranged in the same manner as in conventional tankers and are capable of carrying oil or ballast as required. These ships are fitted with Inert Gas System (IGS) and Crude Oil Washing systems (COW) 1.3.4) ORE / BULK/ OIL CARRIERS; This type vessel is designed to basically carry Ore, Grain and other dry bulk cargo. The vessel has large clear holds with no tween decks. The engines are located aft as in a tanker and the hatches are provided with gas tight hatch covers. Hopper tanks and double bottom tanks are used to carry ballast to enable the OBO to load and discharge liquid cargo. The holds are connected by a duct system or pipeline system to the pump. The duct keep (in duct system) may be divided into a cargo holds to the cargo pump room and is used for loading and discharging liquid cargo to/from the holds. The ballast duct connects the double bottom tanks and the lower hopper tanks to the ballast tanks and used for ballasting and de-ballasting these tanks. The duct keel may in other cases be used as a pipe tunnel for all pipelines leading to and form the tanks and holds. Liquid, Cargo is loaded in the holds. OBOs are provided with Inert Gas and Crude Oil Washing systems. 1.3.5) BITUMEN CARRIERS; Bitumen can be described as a black to dark substance, which can be solid, semisolid, viscous liquid according to temperature. It is derived from certain types of crude oil and is generally classified according to its penetration number.

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Bitumen is used in the manufacture of asphalt and several other similar products. It is transported in bulk by sea and on land by special rail cars which are equipped handle, it but in some case it is blocked and shipped as a solid. Bitumen ships are specially built to handle these products at high temperatures. Not only are the ships equipped with wing tanks and double bottoms to isolate the cargo tanks form the shell but also heating coils are rather more elaborate than in normal ships. Mattresses or layers of coils are to the covering the bottom of the tanks Additional mattresses or layers of coils are provided at different levels in the tanks. Piping and pumps in the room as well as on deck are provided with lagging and the deck lines are often provided with a steam trace. In addition to this most grades of bitumen are handled at temperatures that exceed 12c, below this temperatures they become hard to handle. This type of vessels are generally equipped with two pumping systems which are segregated form each other. The bitumen cargo system is served by one system, which is used for nothing else while the vessels in the bitumen trade. The wings tanks and double bottoms are served by the other system, which handles the ballast. While the vessels is in this trade can also be used to handle cargo should the vessel carry any cargo other than bitumen due to the fact that bitumen is a fairly heavy cargo. The center tanks provide sufficient cubic capacity to give vessels a full cargo and bring her to her marks. 1.3.6) GAS CARRIERS; Gases such as petroleum gas, Natural gas and chemical gases are shipped at sea in a liquefied form. There are two basic types of gas tankers viz. Pressurized and refrigerated ships. The gas cargo is carried in liquid form either under pressure in a pressurized container at ambient temperature or cooled to below its atmospheric temperature. {Boiling point temperature in a refrigerated containment at ambient pressure}. Another category of gas carrier is the semi-pressurized type. On such ships the cargo is carried in liquid form by partially cooling and partially pressurizing the cargo. On refrigerated and semi-pressurized ships the cargo tanks are insulated to avoid heat penetration. 1.4.0) TANKER TERMINOLOGY; The International Safety Guide for Oil Tankers and Terminals (ISGOTT) provides a reasonable comprehensive list of tanker terminology. It would be useful to discuss some of the more complicated and technical terms for definitions.

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ANTISTATIC ADDIVITVE: It is a substance added to petroleum products to raise its electrical conductivity above 100 picosiemens/metre to prevent accumulation of static electricity. APPROVED EQUIPMENT: is an equipment of a design that has been tested and approved by an appropriate authority, such as Govt. or classification society. The authority should have certified the equipment as safe for use in a specified hazardous atmosphere. AUTO IGNITION: It is a process where the ignition of combustible material takes place without initiation by a spark or a flame, when the material has been raised to a temperature at which self-sustaining combustion occurs. BONDING: It is the connecting together of metal parts to ensure electrical continuity. CATHODIC PROTECTION: It is the prevention of corrosion by electrochemical techniques. It may be applied on tankers either externally to the hull or internally to the surfaces of tanks. At terminals, it is frequently applied to steel pipes and Fender panels. CLIMGAGE: Oil remaining on the walls of a pipe or on the surfaces of tank interiors after the bulk of the oil has been removed. COLD WORK: The work, which cant create a source of ignition. COMBINATION CARRIERS: A ship, which is designed to carry either petroleum cargoes or dry bulk cargoes. COMBUSTIBLE/FLAMMABLE: Is a substance capable of being ignited and or burning. COMBUSTIBLE GAS INDICATOR (EXPLOSIMETER): Instrument for measuring the composition of hydrocarbon gas or air mixture, usually giving the result as a percentage of lower flammable limits. DANGEROUS AREA: This is an area on the tanker, which for the purpose of the installation and use of electrical equipment is regarded as dangerous. DRY CHEMICAL POWDER: A flame-inhibiting powder used in fire fighting. EARTHING: The electrical connection of the equipment to the main body of the earth to ensure that it is at earths potential. On board the ship the connection is made to the main metallic structure of the ship, which is at earths potential because of the conductivity of the sea.

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ENTRY PERMIT: It is a document used by a responsible person on the ship permitting entry to a space or compartment during a specific time interval. EXPLOSION PROOF / FLAME PROOF: Electrical equipment is defined and certified as explosion proof/flame proof when it is enclosed in a case which is capable of withstanding the explosion within it of a hydro-carbon gas/air mixture or other specified flammable gas mixture. It must also prevent the ignition of such a mixture outside the case either by spark or flame form the internal explosion. The equipment must operate at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby. FLAME ARRESTER: A permeable matrix of metal or ceramic or other heat resisting materials which can cool a deflagration flame and any combustion products below the temperature required for the ignition of the unrelated flammable gas on the other side of the arrester. FLAME SCREEN: A portable or fitted device incorporating one or more corrosion resistant wire woven fabrics of very small mesh used for preventing sparks form entering tank or vent opening for a short time preventing the passage of flame. FLAMMABLE RANGE: The range of hydrocarbon gas concentrations in air between the lower and upper flammable explosive limits. Mixture within this range is capable of being ignited and burning. FLASHLIGHT: a battery operated hand lamp. An approved light is one, which is approved by a competent authority for use in a flammable atmosphere. FLASHPOINT: The lower temperature at which a liquid gives off sufficient gas to form a flammable gas mixture near the surface of the liquid. It is measured in the laboratory in a standard apparatus using a prescribed procedure. FOAM: An aerated solution used for fire prevention and fire fighting. FOAM CONCENTRATE: The full strength received form the supplier that is diluted and processed to produce foam. FOAM SOLUTION: The mixture produced by diluting foam concentrate with water before processing to make foam. FREEE FALL: The unrestricted fall of liquid into a tank. GAS-FREE: When sufficient fresh air has been introduced into a compartment to lower the level of any flammable, toxic or inert gas, it is called as gas free.

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GAS GREE CERTIFICATES: A certificate issued by an authorized, responsible person confirming that at the time of testing a tank, compartment or container, it was gas free for the specific purpose. HALON: It is a homogenate hydrocarbon used in fire fighting which inhibits flame propagation. HAZARDOUS AREA: This is an area onshore, which for the purpose of the installation and use of electrical equipment is regarded as dangerous; such hazardous areas are graded into hazardous zones depending upon the probability of the presence of a flammable gas mixture. HOT WORK: The work involving sources of ignition or temperature sufficiently high to cause the ignition of flammable gas mixture. This includes welding work, burning or soldering the equipment, blow torches, some power driven tools, portable electrical equipment which is not intrinsically safe or contained within an approved explosion proof housing, sand blasting equipment or internal combustion engines. HOT WORK PERMIT: A document issued by responsible person permitting specific hot work to be done during a specific time interval in a defined area. HYDRO-CVARBON GAS: Gas composed entirely of hydro-carbons. INERT CONDITION: This is a condition in which the oxygen content throughout the atmosphere has been reduced to 8% or less by volume by addition of inert gas. INERT GAS: A gas or a mixture of gases such as flue gas containing in-sufficient oxygen to support the combustion of hydrocarbons. INERT GAS DISTRIBUTION SYSTEMS: All piping, valves and associated fittings to distribution inert gas form the gas plant to cargo tanks, to vent gases to atmosphere and to protect tanks against excessive pressure or vacuum. INERT GAS PLANT: All equipment specially fitted to supply, cool, clean, pressurize, monitor, and control delivery of inert gas to cargo tanks systems. INERT GAS SYSTEMS (IGS): An inert gas plant and inert gas distribution systems together with means for preventing back flow of cargo gases to the machinery spaces, fixed and portable measuring instrument and control devices. INERTING: The introduction of inert gas into a tank with the object of attaining the inert condition.

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INSULATION FLANGE: A flanged joints incorporating an insulating gasket sleeves and washer to prevent electrical continuity between pipelines, hose strings or loading arms. INTERFACE DETECTOR: An electrical instrument for detecting the boundary between oil and water. INTRINSICALLY SAFE: An electrical circuit or part of a circuit is intrinsically safe if any spark or thermal effect produced normally (i.e. joy breaking or closing the circuit) or accidentally (i.e. by short circuit or earth fault) is incapable under prescribed test conditions of igniting a prescribed gas mixture. LOADING OVERALL: The loading of cargo or ballast over the top through an open ended pipe or by means of an open-ended hose entering a tank through a hatch or other deck opening resulting in the free fall of liquid. LOWER FLAMMABLE LIMIT (LFL): The concentration of hydrocarbon gas in air below which there is insufficient hydrocarbon to support and propagate combustion, sometimes referred to as lower explosive limit (LEL). MOORTING WHICH BRAKE DESIGN CAPACITY: The percentage of the breaking strength (when new) of the mooring rope or wire it carries at which the winch brake is designed to yield may be expressed as percentage or in tones. NAKED LIGHTS: Open flames or fires, lighted cigarettes, cigars, pipes or similar smoking materials, any other unconfined sources of ignition electrical and other equipment liable to cause sparking while in use and unprotected light bulbs. NON-VOLATILE PETROLEUM: Petroleum having a flash point of 60 degree Celsius (140 degree f) or above as determined by the closed cup method of test. OBO / OIL ORE: See combination carrier. OXYGEN ANALYSES/METER: An instrument for determining the percentage of oxygen in a sample of the atmosphere drawn from a tank pipe or compartment. PACKAGED CARGO: Petroleum or other cargo in drums packages or other containers. PETROLEUM: Crude oil and liquid hydrocarbon product derived form it. PETROLEUM GAS: gas evolved form petroleum. The main constituents of petroleum gases are hydrocarbons but they may also contain other substance such as hydrogen supplied or lead alkyls as minor constituents.

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POUR POINTS: The lowest temperatures at which petroleum oil remains fluids. PRESSURE SURGE: A sudden increase in the pressure of the liquid in a pipeline brought about by an abrupt change in flow velocity. PRESSURE/VACCUM RELIFE (P/V VALVE): A device, which provides for the flow of small volumes of air or inert gas mixture caused by thermal variations in a cargo tank. PURGING: The introduction of inert gas into a tank already in the inert condition with the object of 1. 2. Further reducing the existing oxygen gas content; or Reducing the existing hydrocarbon gas content to a level below which combustion cannot be supported if air is subsequently introduced into the tank.

PYROPHROIC IRON SULPHIDE: Iron supplied capable of a rapid exothermic oxidation with incandescence when exposed to air, which is capable of igniting flammable hydrocarbon gas/ air mixture. REID VAPOUR PRESSURE (RVP): The vapor pressure of a liquid determined in a standard manner in the Reid apparatus at a temperature of 100 degree f (37.8 degree c) and with ration of gas to liquid volume of 4: 1. RESPONSIBLE OFFICER / PERSON: A person appointed by the employer or the master of the ship and empowered to take all decisions relating to his specific task having necessary knowledge and experience for the purpose. RESUSCITATOR: Equipment to assist or restore the breathing of a man overcome by gas tries lack of oxygen. SELF-STOWING MOORING WINCH: A mooring winch fitted with a drum on which wire or rope is made fast and automatically stowed. SOUR CRUDE OIL: A crude oil containing appreciable amounts of hydrogen supplied or mercaptans. SPONTANEOUS COMBUSTION: The ignition brought about by heat producing (exothermic) chemical reaction with in the material itself without exposure to an external source of ignition. STATIC ACCUMULATOR OIL: oil with an electrical conductivity less than 100 pico siemens/metre (ps/m) so that it is capable of retaining significant electrostatic charge.

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STATIC ELECTRICITY: The electricity produced on dissimilar materials through physical contact and separation. STATIC NON-ACCUMULATOR OIL: An oil of electrical conductivity greater than 100 picot siemens/ meter (ps/m) which renders it incapable of retaining a significant electrostatic charge. STRIPPING: The final operation in pumping bulk liquid from tank or pipeline. TANKERS: A ship designed to carry liquid petroleum cargo in bulk including combination carrier when being used for the purpose. TENSION WINCH (automated or self-tensioning mooring systems): A mooring winch fitted with a device, which may be set to maintain the tension on a mooring line automatically. TERMINAL: A place where tankers are breathed or moored for the purpose of loading or discharging petroleum cargo. TERMINAL REPRESENTATIVE: The person designated by the terminal to take responsibility for an operation or duty. THRESHOLD LIMIT VALUE (TLV): The time-weighted average concentration of a substance to which nearly all workers may be repeatedly exposed for a normal 8hour workday or 40 hour workweek day after day without adverse effect. TOPPING OFF: The operation of completing the loading of a tank to a required ullage. TOPPING UP: The introduction of inert gas into a tank, which is already in the inert condition with the object of raising the tank pressure to prevent any ingress of air. TORCH: see Flashlight. TOXIC: Poisonous to human life. TRUE VAPOUR PRESSURE (TVP): The true vapor pressure of a liquid is the absolute pressure exerted by the gas produced by evaporation form a liquid when gas and liquid are in equilibrium at the prevailing temperature and the gas/liquid ratio is effective zero. ULLAGE: The depth of the space above the liquid in a tank.

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UPPER FLAMMABLE LIMIT (UFL): The concentration of a hydrocarbon gas in air above, which there is insufficient air to support and propagate combustion sometimes, referred to as supper explosive limit (UFL). VAPOUR: A Gas below its critical temperature. VAPOUR SEAL SYSTEM: Specially fitted equipment which enable the measuring and sampling of cargoes contained in inerted tanks without reducing the inert gas pressure. VOLATILE PETROLEUM: Petroleum having flash points below 60 degree c (140 degree f) as determined by the closed-cup method of testing. WATER FOG: A suspension in the atmosphere of very fine droplets of water usually delivered at high pressure through a fog nozzle for use in fire fighting. WATER SPRAY: A suspension in the atmosphere of water divided into coarse drops by delivery through special nozzles for use in fire fighting. WORK PERMIT: A document by a responsible person permitting specific work to be done during a specific period in defined areas.

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CHAPTER 2HYDROCARBON STRUCTURE2.1.0) INTRODUCTION: The organic compounds consisting of only hydrogen and carbon are called hydrocarbons On the basis of structure these are divided into 3 Open Chain (acyclic) ---- aliphatic hydrocarbons 3 Closed Chain (cyclic) Open chain hydrocarbons are further divided into: 3 Saturated>Paraffins 3 Unsaturated hydrocarbons In the IUPAC nomenclature, Paraffins are called as ALKANES. The main source of alkenes is 3 Petroleum Natural gas 3 Natural gas Petroleum contains large amounts of liquid hydrocarbons along with little solid paraffin wax dissolved in it. It is the main source of Alkenes containing unto 40 carbon atoms. Natural gas contains mainly lower Alkenes. It consists of Methane 80% Ethane 10% Mixture 10% The natural wax found near petroleum wells is a mixture of solid hydrocarbons. Fuel gas obtained form coal contains about 32% methane. Methane is found near marshy places. It is formed by decomposition of vegetable and animal waste with bacteria. Methane can be said to be simplest hydrocarbon and is the main constituent of natural gas. One Methane molecule consists of 4 hydrogen atoms and one carbon atom. In order to separate the gases form the crude oil, it has to pass through the process units called as Stabilizer and the residual crude oil thus obtained is called as Stabilized Crude. Crude stabilized oil gives off hydrocarbon vapors form its surface. Both gaseous hydrocarbons (methane, ethane, propane, butane) & liquid hydrocarbons (pentane, hexane) evaporate out of the crude oil.

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The molecules of hydrocarbons compounds are termed as a light & heavy according to the number of carbon atoms contained in each molecules. Methane is substantially lighter than air. Ethane has approximately the same density as air. Propane, butane & higher hydrocarbons are heavier than air. The gas mixtures given off form crude oil & sediments are all heavier than air. The process of refining crude oil will produce a number of fractions. Each fraction consists of a range of petroleum molecules, which at atmosphere temperature & pressure will be gas, liquid or solid. Each fraction has properties specific to itself. Common fractions (products) obtained form crude oil are: Methane Propane Butane

2.1.1) GENERAL CHARACTERISTIC OF HYDROCARBONS: State: Methane, ethane, propane, and butane are colorless, odorless gases. The Next thirteen members (from C5 to C 13) are colorless odorless liquids. From C 18 onwards they are solids. Density: all of them are lighter than water. Solubility: the solubility decreases with increase in molecular weight they are non polar in character. Boiling points: with the increase in molecular size the B. P. increases Physical constants of some hydrocarbons Name METHANE ETHANE PROPANE BUTANE PENTANE HEXANE Formula CH4 C2H6 C3H8 CH10 C5H1 C6H14 Melt. Pt. co - 182.5 - 172 - 187.7 - 138.4 - 129.7 - 95.3 Dens .424 .546 .582 .579 .66 .659 B.P. co - 161.5 - 88.6 - 42.1 - .50 36.1 68.7

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When crude oil is forced or pumped out of well, both hydrocarbon gases and solid materials are dissolved in the oil. When the pressure will reduce the gases will bubble out. Following is the example of liquid hydrocarbons: 3 3 3 3 3 Petrol Paraffin Gas oil Diesel oil Heavy fuel oil

Solid hydrocarbons are: 3 Grease 3 Wax 3 Bitumen Petroleum or its sediments give of hydrocarbon gases when petroleum or its sediments burn hydrocarbon gases are released form its surface and they react with oxygen in the air and hear is generated. During a fire the strong generation of heat will tend to release increasing amount hydrocarbon gases form the surface thus making fire extinguishing more difficult. When hydrocarbon gases form petroleum or its sediments are mixed in the right proportion with air resulting mixture is liable to be explosive. The similarity between a cargo tank explosion and an oil fire is that in both cases it is the hydrocarbon gases react with the oxygen in the air resulting in the generation of hears. The difference between such an explosion and an oil fire is that in the case of an explosion the hydrocarbon gases and the oxygen are already mixed before ignition takes place so that combustion takes place very rapidly the temperature increase rapidly accompanied with a consequent increase in pressure which results in the tank bursting open whereas in the case of an oil fire in open air the hydrocarbon gases are given off from the surface in limited amounts and the oxygen supply is limited by air circulation whether a mixture of hydrocarbon gas and air is flammable depends upon the ratio of the Mixture. The diagram above shows the concentration of flammable gas in a flammable gas/ air mixture. Too rich denotes a mixture where the concentration of flammable gas is so high that is cannot be ignited. To lean denote a mixture where the concentration of flammable is too low to be ignited. The points at which a lean mixture becomes flammable is called the LFL and the points at which the flammable mixture becomes rich is called UFL for hydrocarbon gases emitted form crude oil the LFL is assumed

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to be 1% the UFL is assumed to be 10% by volume of hydrocarbon in air. Shows the explosion danger depends on the concentration of oxygen (increasing towards the right) and of the concentration of hydrocarbon gas (increasing upwards), a corresponds to a tank containing 9% by volume of HC (hydrocarbon gas) 3% by volume of O2 (oxygen) the mixture has such low oxygen concentration that it cannot be ignited if it is diluted with air it can be ignited by a sparks or heat b corresponds to a tank containing 1% HC by volume and 4% oxygen by volume the mixture cannot be ignited even if it is diluted with air, c corresponds to a tank containing 0.5% HC by volume and 21% oxygen by volume the mixture is too lean to be ignited. 2.2.0) HAZARDS OF PELTROLEUM CARGOES: Potential for fire and explosion; The ability of petroleum to create flammable vapor is a major factor contributing to its hazardous nature. Liquid petroleum does not ignite. It is the vapor given off by the liquid petroleum, which burns as a visible flame. The quantity of petroleum vapors available given off by a petroleum liquid depends on its volatility. Petroleum liquids, which vaporize easily, are considered more volatile. There is direct relationship between the vapor pressure of a petroleum liquid and its volatility. Higher the true vapor pressure of a petroleum cargo higher its volatility because its capability of vaporizing is higher. Vapor pressure increases with temperature and reaches a maximum at the boiling temperature of the petroleum. FLASHPOINT: The lowest temperature at which oil gives sufficient vapors to form an explosive mixture with air is referred to as flash point of the oil. When hydrocarbon vapor is mixed with oxygen, in the right proportion, an explosive mixture is produced. A mixture of vapor and oxygen will only ignite when it is within the flammable range. The concentration of percentage by volume in air is used to define flammable range. The working flammable range of mixture of petroleum vapor in air can be taken as 1% to 10% by volume. The three essentials necessary for a fire to commence are: Oxygen Flammable material Source of ignition Three sides of the triangle may represent the three essentials. The complete triangle represents an active fire. The removal of any one side will extinguish the fire. The methods of extinguishing a fire are: Removal of oxygen (smothering) Removal of ignition source (cooling)CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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Inhibition of the burning process. The removal of flammable materials is not practicable on ships carrying liquid petroleum in bulk. The removal of oxygen with a view to achieve fire prevention is done by the use of inert gas. The use of inert gas can reduce the oxygen content in the cargo tank below that necessary to produce a flammable mixture. Covering the surface of the oil with a blanket of inert gas will prevent oxygen form making contact with the vapor form the oil. The reduction of ignition sources is achieved by strict fire precautions. On board an oil tanker flammable mixture may be found where they are least expected. Every effort is made in the design, construction, equipment and operation of an oil tanker to avoid ignition sources coming in contact with a flammable gas/ air mixture. Water spray is an efficient cooling agent. Water sprays have been successfully used on board oil tankers to fight oil fires by achieving cooling. Toxic effects; The hazards to health on board oil tankers are Skin contact with liquid petroleum Swallowing of liquid petroleum Breathing of petroleum vapors Compounds of lead contained in cargo

The following precaution should be taken to avoid the above health hazards: Strict control of entry into pump room, cargo spaces and other enclosed spaces. Through ventilation of any spaces to be confirmed before entry. Use of adequate protective clothing. Through cleaning of body and personal clothing after contact with petroleum. Continuous monitoring of atmosphere in working space for petroleum vapors and hydrogen sulphide.

Skin contact with light petroleum products causes irritation and dermatitis because they remove the essential natural oils of the skin. Petroleum can block skin pores and causes rash. This rash is sometime referred to as oil acne. Some heavy petroleum such as lubricating oil can produce more serious long-term effects in contact with the skin over long periods they may cause skin cancer. There is particular risk of cancer of the scrotum. Swallowing of petroleum causes acute discomfort and nausea. If liquid is inhaled into the lungs there is severe risk of suffocation through interference with the normal oxygen / carbon dioxide transfer taking place during breathing the liquid swallowed will tend to vapourise and the vapors could be breathed into the lungs.

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The inhalation of petroleum vapors will create the following symptoms progressively. Dullness of sense of small Dizziness Diminished sense of responsibility Headache Eye irritation Staggering Loss of consciousness Arrest of breathing Arrest of heart Death

Some petroleum cargoes release a dangerous gas called hydrogen sulphide. This gas smells of rotten eggs. It dulled the sense of smell thus it is doubly dangerous. Some people can tolerate petroleum vapors better than other. The lack of early ill effects should not be taken to mean that there are no dangerous vapors present, as the onset of the effects of the vapors may take longer than expected. 2.4.0) OXYGEN DEFICIENCY: The oxygen content of air is 21% by volume. The oxygen content is enclosed space may be lower. One of the reasons for such low oxygen content may be because the atmosphere in the space is inerted. Oxygen content may also be reduced owing to chemical reactions (e.g. rushing burning paint drying).

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CHAPTER 3TANK ARRANGEMENTSForm the first simple design the tanker grown unit it has become one of the most highly developed and efficient contemporary ships type the oceangoing tanker is a very large ship with flush upper deck and a large multi flat deckhouse and bridge structure aft in outward appearance a tanker has a clearly distinguishable silhouette. 3.1.1) FORE PEAK AFTGER PEAK TANKS : These spaces are used for the carriage of ballast only it is not unusual for takers to be provided with a forward pump room abaft the fore peck tank within which is located the ballast pump for ballasting and de-ballasting the fore peak tank the ballast pump located in the engine room is used for ballasting and de-ballasting the after peak tanks the teak tanks are never used for the carriage of oil cargo or bunker fuel oil. 3.1.2) DEEP TANKS; Tankers are usually provided with tanks forward and aft for fuel oil. A fuel transfer pump located in the forward pump room forward services the deep tanks and the deep tanks aft are serviced by fuel transfer pump located in the engine room. Due to the nature of the oil (fuel oil) carried in the deep tanks it is not necessary for the deep tanks to be internally coated with paint. Deep tanks are most often fitted with heating arrangements to heat the oil fuel and enable it to flow easily. 3.1.3) CARGO TANKS; The cargo tanks of oil tankers located abaft fore peak tank or forward fuel oil tanks (if any) and forward of the main pump room aft. Longitudinal and transverse oil tight bulkheads into tanks subdivide the ship hull in this region. The cargo are provided with very small opening on the weather decks these openings are provided with oil tight closing appliances. Liquid cargo to is loaded through pipelines, which are permanently installed within the tank deck areas. Pipelines are also utilized for emptying the cargo tank of the liquid cargo. Depending upon the grade of oil carried the internals of the cargo tank may be coated with special quality of paint which will not contaminate the cargo carried. This becomes particularly necessary when carrying white oil as rested tanks may tend to contaminate the cargo and the cargo may also corrode the steel of cargo tanks. It is not a usual practice on crude oil carriers. Cargo tanks may also be provided with heating arrangement to enable heating of viscous cargoes.CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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3.1.4) PUMP ROOM The cargo pump room of an oil tanker is the nerve center of the cargo system of the ship. It is located at the after end of the cargo tanks area. Pipelines for the cargo tank lead to cargo oil pumps located in the pump room. This place on board an oil tanker is the most potentially hazardous spaces. This is the only compartment frequented by personnel on an oil tanker in to which oil cargo enters (within pipelines) if due to any malfunction or breakdown of pumps pipeline or valves oil leakage occurs personnel will immediately be susceptible to the hazardous of the petroleum cargo. The pump room is provided with efficient forced ventilation systems. It is kept operating prior and during the course of any cargo ballast related operations. 3.1.5) COFFERDAM: This name given to empty compartment between double transverse bulkheads, which provide a space between oil tanks and other compartment. The rules require that a cofferdam be fitted at each end of the cargo area. Cofferdam or pump room is also provided between sections of cargo oil. Ballast space may be accepted as cofferdam. Cross-bunker tanks are also accepted as cofferdam. 3.1.6) SEGREGATED BALLAST TANKS: Most tankers are required to be fitted with segregated ballast tanks (SBT). These tanks are connected to a completely separate system of pumps and pipelines for clean ballast only. SBT are defined as tanks, which are completed, separated form the cargo oil and fuel oil systems and which permanently allocated for the carriage of ballast. Sets should be located so as to offer some degree of protection against stranding and collision. Ideally this would mean the ship is provided with double skin and double bottoms of specified width and depth. Newly built tankers are required to be of double hull construction. The double bottom and wing tanks of the double hull to be solely for the carriage of ballast. 3.2.0) PIPING ARRANGEMENT: Internal piping in tanks & pump room; A modern tankers internal piping in the cargo tanks consists of straight pipelines running longitudinally through the cargo tanks with branches form each longitudinal line to feed a group of tanks. The pipelines in the cargo tank are located about a meter form the tank bottom. The longitudinal lines in the cargo tank terminate in cargo pump room at the cargo pump.

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Over the years four main systems of pipelines arrangement within the cargo tanks were developed namely: 1. 2. 3. 4. Direct line system Ring main system Free flow system Combined system

3.2.1) The direct line system: It consists of longitudinal lines in the center tanks branching to suction bell mouth in the center and wing cargo oil tanks. The direct line system enable faster loading and discharging rates and is also claimed to provide better suction due to the lack of many bends in the line. This system is most popular on the crude oil carriers. 3.2.3) Ring main system This system provides for handling of several different types of oil simultaneously. The main pipelines in the tanks are laid in a ring format. Cargo is pumped out through one direct suction line or through systems of crossover valves and master valves by an intersecting suction line. The system is very versatile. Mimic diagrams of line layout and a skeleton drawing of a complete ring main Dig pipeline are shown above. During loading operation oil can be passed downward through the drop line to the bottom loop passing along the wing tanks. When this being carried out closing the bulkhead master valves in the pump room isolates the pump room lines. Study o f the drawing will reveal that grades of oil can be carried at the same time. Each grade can be loaded along a separate section of line and discharging in like manner a separate line being used for each grade. 3.2.3) Free Flow System: The flow of oil form a ship tanks can be improved if it is does not have to pass through pipelines but can run freely through valves in the bulkheads themselves. Such systems are now in use, more ships are being built to this design, and for a certain number of the larger ships in the crude trade there is much to commend what has become known as the free flow systems. Large rectangular sliding valves are set in the tank bulkheads and when these are open throughout the ship she is literally opened up directly to the pumps. There will be a natural tendency for her to lighten forward first forming a wedge of oil towards the pump room at the after end so the main centrifugal pumps can be used almost to the last without any stripping be required. In fact when the main pumps are used in conjunction with educators, although these are by no means universal or accepted by all, striping pumps are often

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not fitted at all. Some free-flow layouts also have a ring line to make tank cleaning and blasting easier. 3.3.0 VALVES: A valve is a device used to control or regulate the flow of fluid (liquid or gases) through a pipeline. There are different types of v/vs. used in the various systems of which most common types are; 1. 2. 3. 4. Globe valves Non return valves Gate (sluice) valves Butterfly valves

3.3.1 GLOBE VALVES: It can be either screwed down (SD) or screwed down non return (SDNR) type of valves. Normally it consists of a v/v lid, (circular type of closing device) with some arrangement of wings or centrally located guide rod on the base of the disc. This guides the v/v lid up & down in the v/v seat bush which a fitted in the v/v chest. The fluids enters the body form underneath the v/v lid and passes through from the top of the v/v lid hence the fluids has to make change in the flow direction causing energy wastage. In SD type the v/v lid position is determined by the position of the operating spindle whereas in SDNR type the v/v lid will remain seated even when the spindle is drawn up the v/v lid will move off its seat only by fluids pressure acting form below & will remain open till pressure below the v/v lid is more than pressure form above. For preventing fluids form leaking past the v/v spindle a gland is provided with packing material. The packing material / flange jointing depends upon the type of fluids flowing through the v/v. The packing is cut to size to suit the sealing area. The cutting edges can either be straight or beveled. The butts are staggered in place in such a way that the built ends are not in one straight line. The gland tightening torque should be just sufficient to allow free movement of the spindle without leakage. Also enough allowance is retained for nipping of the glands in case of leakage. The maximum v/v lift is quarter of the lid diameter. The body of the v/v is of casting and seat is either integral with the v/v body or is detachable bush type. The seating face is machined to mate with v/v lid seating surface to seal the passage through the v/v. 3.3.2) NON-RETURN VALVE;

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3.3.3) GATE VALVE; A gate v/v is also known as sluice v /v. In this type a wedge shaped v/v disc is used as closing device. The v/v disc fits into a wedge shaped opening in the v/v body. The sealing faces are machined to mate in the closed position. The main feature of this v/v is high flow rate with minimum wastage of energy. This v/v also allows the flow in either direction while providing a proper sealing due to its shape. The v/v spindle normally has square threads. If required this type can be designed to operate remotely as well as manually. The v/v operated by jacking up the lid in the bonnet of v/v body through spindle form its closed position. 3.3.4) BUTTERFLY VALVE This type has a v/v disc which swivels about the central axis in either open or close position. The sealing faces are Eastover rings, which eliminates the conventional lapping of mating surface. In overhaul of this type renewal of v/v lining and 0 ring rubber seal on the v/v shaft is required. Advantage of Butterfly v/v over Gage v/v: The butterfly v/v is compact in size hence requires less headroom. The butterfly v/v requires much less time to operate form open to close or vice versa however in case of gage v/v the gate has to be raised completely in to the v/v body bonnet requiring longer duration for operating v/v. The butterfly v/v requires low cost of over hauling.

Disadvantages: The butterfly v/v may tend to slam shut in any throttle position unless interlocking device is provided. Precaution while operating a v/v care should be taken not to use undue amount of force for opening or closing it. 3.3.5) OVERHAULING OF A VALVE: Mark the flanges prior to slack ending the nuts so as ensure the proper relocation of v/v on replacement after o haul. Before removing any v/v form place ensure the pipeline has been isolated and there is no pressure in the line. Dismantle the v/v and clean all the parts thoroughly. Check the condition of the v/v lid seat. Lap the mating face by using appropriate grinding paste depending upon the condition of the surface. Following are the various grade of grinding paste, which can be used (i) (ii) (iii) Coarse/rough Medium FineCENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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(iv)

Extra fine

Remove the old gland packing and clean the area. Select proper size/ materials of the packing and insert in the place provided the number of packing should be sufficient to give proper sealing as well as nipping up of the gland if required. Clean all the flanges preferably without using any abrasive tools to prevent any damage to the surface. Required number of new joints of proper dimension and thickness are cut to size. Make sure that all nuts blots and studs are free. Assemble all the parts in order as per the marking made before dismantling the v/v. Fit the v/v in place put the line in service and check leakage. Nip up the gland as required. 3.4.0) PUMPS A pump is a machine used to pressure and transfer fluids form one point to another. This is achieved by imparting energy to the fluids thus enabling it to flow under pressure. A prime mover imparts this energy to the fluids via the pump. Fluid flow takes place by maintaining a pressure difference between points. Normally the pump draws the liquid into a by over eating a vacuum effect on the suction side (this drops the pressure below atmosphere level if so required). The fluids drawn into the pump is discharged under pressure into the pipeline. Pumps are designed for certain optimum capacities so ate piping and valves in the system should be suitably dimensioned. A pumping system comprises pumps, prime movers with associated pipeline and valves. A pump has suction side and discharge/ deliver side. Pumps are subdivided into two basic groups: (A) Dynamic Type, (B) Positive displacement type

3.4.1) DYNAMIC TYPE: In this type energy is continuously added to the pump to increase the fluids velocities egg Centrifugal pump (single or multi stage), Educators or Ejectors. (i) Centrifugal pump

It is non-self priming pump. This pump cannot operate efficiently if vapors are induced along with fluids into the pump. The separate out these vapors and eliminate them, provision has to be made using a purging cock or some other vapors / air extracting pump/ device. This pump is relatively simple in construction and has small resistance, to flow of fluids through them. It has large through put capacities (that is there size / capacity ratios are very high) Pump may either be horizontally or

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vertically operated. Prime mover, which drives the pump, could be an electric motor, diesel engine, turbine or hydraulic motor. Basic design consists of a split casing of volute spiral form. An impeller, which runs in wear/ mouth, rings and mounted on a drive shaft, which rotates in bush or any selfaligning type of bearing. The fluids are prevented form leaking along the shaft, but conventional type packing glands or mechanical seals. The mouth or wear ring in which the impeller revolves serve as a separation between the suction and pressure sides of the pump. Impellers are usually fixed to the shaft by keys. Fluids are induced into the eye of the impeller at their center due to suction effect caused by centrifugal force and the design of the vanes of the pump. Energy is supplied by the prime mover via the impeller vanes and volute casing. Multistage pump consists of a number of impellers running on the same shaft and forming a number of stages in the pump. The fluids form one impeller is discharged via suitable passages into the eye of the next impeller and so on. The final discharge pressure is the addition of head per stage. In this way high-pressure discharge can be obtained with moderate pump speed. The centrifugal pump can theoretically be run with their discharge valves shut with no differential effect to the pump. As suction and discharge sides are connected within the impellers and fluids merely churns within the casing. In actual operation this churning causes heating of the pump and if allowed to continue will vaporize the fluids, this leading to overheating and wear of the pump parts. Centrifugal pump is started with discharge valve shut. This facilitates priming and allows the pump to start with least load on the prime mover. Once the pressure comes to rate value the discharge valve is gradually opened. (ii) Educator / Ejector; Its operation is based on Bernoullis is principle, which states the the rate of increase of fluid velocities is very rapid then the pressure at that point of the system drops to below the atmospheric level. Thus fluid will be induced into this specially designed pump. In Educator a convergent/divergent nozzle is designed to create very rapid velocities at the outlet of the throat of the nozzle (narrowest point). Thus a vacuums develops in this region & if connected by a pipe and values to the tanks to be stripped, it will educt or remove the fluids efficiently. Here the fluids are discharged along with the stripped fluids, so they must be compatible. Pump delivering the drive must supply the designed pressure to this Educator to operate efficiently as pump has no moving parts, the educator is not damaged if air is drawn into it is capable of producing 85% vacuum which makes it effective for stripping and draining operations. 3.4.2) DISPLACEMENT TYPE:

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In this type, the energy added periodically by application of force, resulting in direct increase in pressure this are also known as self priming type of pumps following pumps are some of the examples of this type Reciprocating pump Gear pump Screw pump Axial piston variable Displacement pump

(I) Reciprocating pump: This type of pump can be mounted either horizontally or vertically, the reciprocating motion can be either through connecting rod form electric motor and reduction gearing or other forms or from direct steam drive reciprocating pump can be either single acting or double acting. In single acting pump, every alternate stroke will give discharge, where in double acting pump, every stroke will give discharge suction and delivery chambers are isolated form each other by means of diaphragm well and set numbers of valves in each chamber. The pump consists of a piston plunger which is reciprocating a cylinder liner the piston is made airtight in the using piston range with butt end the rings can be of metal or of any other suitable materials, depending upon the fluids being handled and its properties. Appropriates appropriate glands are provided to seal the chambers at the connecting rod. Normally, an air vessel is provided on delivery side to dampen the vibrations. The movement of piston will expand the air underneath it, causing pressure drop. The pressure difference thus obtained forces the fluids to be drawn in till piston reverses its direction of motion. Now, piston will force the fluids out of the pump as it starts moving in the opposite direction. If delivery side is blocked, the pump casing may be damaged due to the pressure of the fluids. Hence a relief v/v provided on the discharge side to safeguard the pump form over pressure on reciprocating pump an air vessel is provided on the discharge side to dampen the pressure pulses caused while pumping. (ii) Screw pump: The pump consists of set of screws, which are giving pumping action. These are called screws because of its surface profile. It consists of central drive screw, coupled to prime mover the other screw also known as idler is mashed with drive screw theCENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

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screws the screw are encased in a close fit casing the surface are shaped that they form a tight seal in relation with themselves and the casing the idler screw rotates in opposite direction to that of central drive screw as the screw rotate the tight seal thus formed moves axially and uniformly acting as piston moving in one direction continually the drive screw shaft has suitable sealing arrangement provided at the pump casing. Unlike reciprocating pump it does not set up vibrations a very high speeds secondly this given constant delivery head this pump is normally used for oils sludge discharge. (iii) Gear pump This pump is very similar to screw pump however the impellers are shaped like gears mashed with each other in a pump casing one is known as drive gear coupled to the prime mover through either chain or wheel and other idling gear is mashed with it in such a way to give perfect tight seal and allowing fluids to be carried round between the teeth and the casing appropriate sealing arrangement is provided at the drive shaft and pump casing the pump can also be arranged with wheels to operate in series for pressure pump. In both the screw and gear type pump a relief cum by pass v/v is provided for control of discharge pressure as well for preventing any overpressure in the discharge line. (iv) Deep well /submersible pumps: Are used in specialized tankers (e.g. chemical / product / gas) here a pump is placed in the tank in a well at the bottom of the tank hence the name deep well pump these pump are centrifugal type and are single stage or multiple stage depending on pressure required on the discharge side centrifugal pump are chosen as main discharge pump because of their relatively simple design and high capacities however the disadvantage of these pump are the necessity to prime and in-efficiency if vapors enters the pump by placing the pump in the tanks both these are eliminated thus use of deep well pump though expensive make for quicker discharge time and simper piping systems drive could be electric or hydraulic with drive motor and deck or submerged in tanks the size of the well is usually large enough to allow the dies line of the pump to drain it and be stripped using a screw pump or other suitable arrangement bearings of these pumps are cooled and lubricated by the fluids being discharge which flows around of bearing in the discharge / riser pipe. (v) Booster pump Usually deck mounted and used in conjunction with deep well / submersible pumps. The deep well / submersible pump deliver the cargo to the suction of the booster pump which raised the discharge pressure to shore requirements.

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3.5.0) DRAINING AND STRIPPING: Draining with centrifugal pumps depends entirely on being able to keep air out of the pump whirlpools and eddies around the suction often allows sufficient air to reach the pump for suction to be lost for this reason when using this type of the pump on tanks where the level of the liquid is dangerously low, it is advisable to shut in the suction and party crack open another tank to help feed the pump in this manner the rush of oil from the low tank is reduced and less likely to create whirlpool and at the same time the pump is obtaining sufficient oil form the full tank to compensate for the oil lost when the suction valves was shut in centrifugal pumps are often fitted with a vacuum line which leads to a draining pump the principal being that any air or gas entering the pump is immediately drained off by the vacuum or draining pump before the main pump has time to lose suction. Reciprocating pumps are far better suited for draining than centrifugal pumps they will not loss suction when small quantities of air mixed with oil enter the pump and as a result will drain tanks far drier than a centrifugal pump which does not require much air to make it lose suction when draining with a reciprocating pump the speed of the pump should be reduced till the pump has a nice easy stroke and the gauge shows a maximum vacuum the pump can safety be left running until it is heard to suck air in the tank by shutting down the suction valves and reducing the aperture the pump is assisted in draining the tank dry. 3.6.0) MEASUREMENT OF CARGO LEVEL: To ascertain the liquid level in tanker cargo oil tanks it is necessary to measure manually mechanically or electronically. (a) (b) The amount of liquid in the tank measuring form the bottom of the tank of the surface of the liquid the resulting measurement is known as the sounding. The amount of spaces between the top of the tank (allege plug) and the surface of the liquid the measurement was known as allege.

In the older tankers, ullaging with an ullage stick was common practice. Fast loading or discharging with numerous tanks open at once meant several members of the crew amount of manpower required was considerable, particularly when loading at fast rate the risk of asphyxiating personnel continuously leaning over open ullage hatches could not be ignored. Automatically tank gauging used in oil tankers are largely adapted form similar systems used the oil industry ashore. The float systems is probably most common of the automated tank gauge systems. In the earlier versions the float was suspended for a special hatch by means of an

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ordinary ullage tape. The tape was passed over a flywheel directly under a clear view screen complete with screen wiper. The other end of the tape was secured to a weight suspended in a tube fitted with cleaning solvent extending to the bottom of the tank. The float is heavier than the weight in air but when the tank is being filled or emptied it floats on top of the liquid, rising or falling as the liquid level alter, the tape records the ullage automatically. The float systems is tried and reliable and a broken tape at once lets the operator know he must revert to hand ullaging. A reasonable amount of maintenance will keep the systems trouble-free. The steel tapes provided by the manufacturer have the measurement scale either painted on them or embossed on the actual metal. They are less likely to be defected by cargo with inert gas or other corrosives. Large and more modern ships fitted with the float ullage systems are equipped with a remote read out in a central control room. There are a large number of automated tank gauging systems based on hydrodynamic principals. Such systems have a marked similarity, and it should suffice if we cover them in outlines. Each tank is fitted with one or more open-ended pipes connected to a read gauge and reservoir in the control room. They length of the gauge and the type of liquid with which it is fitted depends on the accuracy required. A small gauge using a heavy liquid like mercury can be used, where accuracy is not required. Where accuracy is required such as when topping up tanks a larger gauge and a lighter liquid are used together with separate pipe to cover the upper section of the tank. How do such systems work. The open ended pipe in the tank is connected to a liquid reservoir in the base of the gauge glass. Nitrogen or another suitable gas is inserted into the pipe until it has purged all the air and its fills the whole length of pipe. The end of the pipe is restricted but the gas is allowed to leak out of the open end in the tank charge in liquid level within the tank result in changed pressure on the gas in the tube which in turn transfers to the liquids in the gauge glass and the level can be read off the calibrated gouge. Electrical capacitance gauge measures the electrical capacitance of a number of submerged segment (3600 mm long) plus the immersed portion of the segment which intercepts the liquid surface capacitance measurement are used to determine automatically the number of submerged segments and the immersed fraction of one segment the fraction is measured by the ratio of two current the current flowing in the partially filled segment and the current flowing in the filled segment immediately below it.

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This is true digital measurement in which the tank is divided into a number of segments typically 5 to 10 that the range of measurement is only the length of one segment and the measured value is added digitally to the height of the bottom of the segment. In theory the capacitance of an elements or segment is depended on the di-electrical constants of its metal and the liquids in which is is immersed however in practice where is ratio measurement is used the properties of liquids are eliminated. The device has district advantage over the mechanically operated float gauge and the servo-operated gauge as it measurement the depth on the liquids whereas the latter measure the ullage. The comparative capacitance gauge therefore consists of number of elements of equal length staked one on top of the other in a vertical tube which rests on the floor of the tank the main advantage of this type a gauge is that is has no moving parts and therefore no friction.

Tank radar gaugeThis type of level gauge consists of a deck mounted transmitter unit a computing unit in the control room and a display unit in the control room the transmitter sends out intermittent radar energy pulses on to the surface of the cargo in the tank echo pulses are reflected back form the surface of the cargo these echo pulse are received at the transmitter unit and conveyed to the computing unit the computing unit converts the time internal between transmission and reception of the radar pulse into depth ullage and displays it on the display unit.

Portable ultrasonic multifunction tank gauging unitThis gauge can measure ullage and interface (oil / water etc) it works on the principles of frequency of a vibrating members in the probe when immersed in different media when the probe is lowered into the cargo tanks the probe vibrating at a high frequency when the liquids cargo in the tank covers the vibrating members the frequency of vibration is changed this change is recognised by the electronic circuit in the portable unit the cause a relay in the amplifier to actuate an audible signal this signal indicates the moment at which ullage must be read off the tape the hand held portable unit may also provided a digital display of ullage. 3.7.0) CARGO HEATING SYSTEMS : Heavy cargoes such as fuel oil becomes very thick and sluggish when cold and in order that such oils can be loaded and discharged without delay it is necessary to keep them heated.

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Today the oil trade is so vast and widespread that the average oil tankers may be trading in the tropics one voyage and in arctic condition the next it is therefore necessary that cargo heating system be designed to cope with extreme conditions. Due to the fact that a loaded tanker has completely little freeboard the temperature of the sea water through which the vessels is passing is of major significance. Cold water washing around the ships sides and bottom and across the decks rapidly reduce the temperature of the cargo and makers the task of heating it much harder warm sea water however has the severe effects and can be very useful in helping to maintain the temperature of the cargo with the minimum of steam. Steam is used to heat the oil in the ships tanks, it is piped form the boilers along the length of the vessels deck generally the catwalk or flying bridge is used for this purpose the main cargo heating steam and exhaust pipes being secured to either the vertical or horizontal girder work immediately below the foot treads at intervals, manifolds are arranged form which the steam for the individual cargo tanks is drawn each tanks has its own steam and exhaust valves which enable the steam to be a shut off or reduced on any of the tanks at will generally the main steam lines are well lagged but obviously it would of the tanks at will generally the main steam lines are well lagged but obviously it would not be a practical proposition to the log the individual lines leading form the manifold to the cargo tanks. The heating arrangement in the actual cargo tanks consists of a system of coils which are spread over the bottom of the tank at a distance of six to eighteen inches form the bottom plating in wing tanks it is the usual practice to extend the coils systems as for as the turn of the bilge, but not up the ships the side. When it becomes necessary to heat cargo, the stem is turned on the individual tanks the coils in the bottom of the tank heat the oil in the immediate vicinity the warm oil rise slowly and is replaced by colder oil thus setting up a gradual circulation system in each tank. The wing tanks insulate the centre tanks on both sides while they themselves are subject to the cooling action of the sea not only through the bottom plating but through the ship side. It is therefore advisable to set the steam values so that wing tanks obtain a larger share of the steam than the centre tanks this is particularly true in some of the more modern vessels where the coils are passed through the longitudinal bulkheads between the centre and wing tanks Heavy fuel oils are generally required to be kept at a temperature ranging between 45OC and 65 OC, (45 deg. C) & (65 deg. C) within this temperature range they are easy to handle. Lubricating oils of which the heavier types requires heating are always the subject of special instructions as they very widely in quality gravity and viscosity.

CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

Some types of heavy grade gas oil have high pour points and it is necessary to kept the cargo well heated to avoid it going solid provided the temperature of this type of oils is ten to fifteen degree above its pour point. If offer no difficulty when loading or discharging though a wax skin well form the sides and bottom of the ship. Some crude which contain paraffin wax or have high vapor points are also heated when transported by sea. The main aim should be to stop excessive deposits of wax forming on cooling surfaces. The heating requirement of such cargoes varies considerably. Wax crude with pour points over 38 OC may require heating to 60 OC. Bitumen cannot normally be carried in ordinary ships as it requires for more heat than the normal cargo systems is capable. For this reason bitumen ships are generally designed so that the cargo tanks are insulated by wing thanks which are reserved for ballast and by double bottoms under the cargo tanks. This coupled with extra coils arranged on platforms at different level helps to keep the bitumen heated. In ships carrying heavy lubricating oils which requires heating the coils are generally ordinary steel pipe type but vessels carrying crude oil which are to be heated are now equipped with cast iron or alloy coils. The reason for this is that the heating surfaces are subjected to excessive corrosion form the lighter fractions in the crude and ordinary steel pipe does not stand up the corrosive action so well as the other materials mentioned.

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CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

CHAPTER 4OPERATIONS4.1.0) LOADING: After the tanker arrives at the berth and prior commencement of loading the tankers will have to provide following information: Details of last cargo carried, method of tank cleaning (if any) state of the cargo tanks and lines. Where the vessels has part cargo on board; grade volume and tank distribution. Maximum acceptable loading rate and topping off rates. Maximum acceptable cargo temperature. Maximum acceptable TVP. Venting method proposed. Ballast disposition and maximum freeboard during operation.

The exchange of information as outlined above will form the base for the conduct of a safe loading operation once the tankers is at the loading berth. The tankers cargo officers and the terminal representative must discuss the proposed operation in detail. The discussion must culminate in an operational agreement which should be in writing between the tankers cargo officer and the terminal representative. The written agreement should contain the following: Ships name, berth date and time. Name and signature of the ship and shore representative. Cargo distribution on arrival Product information namely 1. 2. 3. 4. 5. 6. 7. 8. 9. quantity ships tanks(s) to be loaded shore tanks(s) to be unloaded lines to be used ship/shore cargo transfer rate operating pressure maximum allowable pressure temperature limits venting system

Special electrostatic precautions (if any)

CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

Special precautions to use of automatic shut-off valves Loading plan indicating the sequence in which ships tanks are to loaded with expected timings taking into account 3 3 3 3 3 3 deballasting operations ships/ shore tank change over avoidance of cargo contamination pipelines clearing for loading other operations that may affects flow rate trim and draught of tankers ships stress constraints, The initial maximum and topping off rates Loading stoppage timings (normal & emergency) Venting methods Any bunkering operation planned to run concurrent with cargo operations. The loading plan of a combination carrier must take into account the ships stability constraints and the need to avoid excessive free surface and the loss of stability. Signals of commencement, stoppage, emergency shutdown fire, pollution, emergency or any other emergency should be agreed upon.

An emergency shutdown procedure (ESD) should be agreed between the ship and the terminal and recorded on an appropriate form. The agreement should designate the circumstances in which operation must be stopped immediately. Due to regard should be given to the possible dangers associated with any emergency shut down procedures. After the agreed loading plan has been drawn out the cargo officers must brief the duty officers regarding the same. It is desirable that a copy of the loading plan is made available to the duty officer, the crew on deck attending to the cargo loading operation should also be made aware of the salient features of the loading plan. Prior commencement of loading the shore authorities may insist upon an inspection of the ships cargo tanks especially in the case of clean product cargoes where possible. Inspection of ships tank before loading cargo should be made without entering the tanks. A tank inspection can be made form deck using ullage or sighting ports with, where applicable, the inert gas within the tank at minimum positive pressure. Care must be taken not to inhale vapours or inert gas when inspecting tanks which have not been gas greed. Tanks which are inert may have a blue haze which may make it difficult to see the bottom even with the aid of a powerful torch or strong sunlight reflected by a mirror. Under these circumstances other method such as dipping and measuring of oil having the stripping line or educators to draw form the tank and listen for suction may have to be used. It may sometime be necessary to remove tankCENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

cleaning opening covers to sight parts of the tank not visible form the ullage ports this should only be done when the tank is gas free and the covers must be replaced and secured immediately after the inspection. Where the cargo to be loaded has a cirtical specification. It may become necessary for the inspector to enter the tank. Whenever tank entry is made all due precautions should be taken. Tanks must be tested and found gas before any man entry is attempted. The inert gas plant should be shout down and the inert gas pressure in the tanks to be loaded should be reduced prior commencement of loading unless simultaneous loading of cargo and discharging of ballast form the cargo tanks is to take place. Unless the ships design dictates otherwise cargo must be loaded with the ullage sounding and sighting port securely closed, the gas displaced by the incoming cargo should be vented out to atmosphere via the vent stacks or through the high velocity vent vales. Either of these methods of venting will ensure that gases are taken clear of the cargo. Deck devices fitted to vent stacks to prevent the passage of flame must be checked prior loading to confirm that they are clean, in good condition and correctly installed. The pump room ventilation should be kept operating during loading even if the ships pumps are not running, so that any leakage in the pump room must not cause dangerous gas accumulation. In lining up for the loading, every effort must be made to ensure that cargo pipelines are set in such a manner that cargo need not pass through the pump room to thecargo tanks. In certain tankers it may not be possible to avoid setting lines for loading without passing through the pump room. When all necessary terminal and tankers valves in the loading system are open and the ship has given readiness loading can commence whenever possible. The initial flow should be gravity the shore pumps not being started until the complete system has been checked and the ship advice that cargo is being received in the correct tanks(s). When the pumps have been started the ships shore connection would be checked for tightness prior loading is connected at full rate. Checks for leaks in the pump room and cofferdams tanks not being loaded, double bottoms (if any) ballast tank deck pipelines and over the side should be conducted. If the checks reveal no leaks rate may be increased to maximum. The loading rate should not be changed substantially without informing the ships. many terminals require standby time for stopped pump and it should be understood and noted in the operational procedures form. Before commencing loading at a sea line berth the ship should confirm its full understanding of the communications system which will be used to control the operation a secondary communication system should be provided ready to be brought into immediate action in the event of failure of the primary systems. Before commencing loading through a stern loading line the dangerous area extending not less that 3 meters form the manifold valve aft should be clearly marked and unauthorized personnel should not be allowed within this area during.

CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

The entries loading operation. All openings air inlets and doors to enclosed spaces should be kept tightly closed fire fighting equipment should be laid out and ready for use near the stern loading manifold. A close watch should kept on the sea around ship so that pollution due to leaks are detected earls. The ship should advice the terminal when the final tanks are to be topped off and request the terminal in adequate time to reduce the loading rate sufficiently to permit effective control of the flow on board the ship after topping off individual tanks. Tank filling valves should be shut where possible. Two valves segregation of the topped off tank from other tank should be provided, village should be checked frequently at regular intervals to ensure that overflow do not occur as a result of leaking valves at incorrect operation. The number of valves to be closed during the topping of period should be reduced to minimum the tanker should never close all its valves against a flow of oils as this may lead to serious accident before topping off operations commence at a sea line completion of loading should be done by gravity if pumps have to be used to the end their delivery rate during the standby time should be regulated so that shore control valves can be used as soon as requested by the ship. Control valves should be closed before the ships valves. After completion of loading, responsible officer should check that all valves in the cargo system are closed and that all appropriate tank opening are closed and that all pressure/ vacuum relief valves are correctly set. After oils is refined and in refinery storage tanks it is sampled tested whenever oil is transferred either form a ship to shore storage tanks or the reverse sample tanks place before the operation is commenced and after it is completed. If a tanker is about to load a cargo or oil the ships tanks are inspected and passed as fit or the particular grade of cargo with which it is intended to load her at the same time the oil in the shore tanks is sampled and tested to make sure that it is not contaminated or deterioration form the result of storage after the vessels has started to load. Initial samples are taken in this manner, any drop in specification of the oil will be checked before much of the cargo is loaded if necessary the loading operation can be stopped before too much oil is contaminated with special grade of oil the sampling may be repeated several times during the loading operation. Final samples are taken on the completion of loading operations. They are the final check on the quality of oil loaded and form the basic form which chemists take data for the quality certificate. A copy of this certificate will be placed on board before the vessels sails. Sample can containing samples of each of the grade loaded are sealed and dispatched with the vessels to her destination.

CENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

Composite samples are generally taken in the case of cargoes such as crude oil the sample may merely take a portion of the sample obtained form each tank and pour it into a large sample can containing similar samples form other tanks. A meticulous record of the whole loading operation must be maintained. A record of each event must state the time of each event also. 4.2.0) LOADED VOYAGE: During the loaded passage the volume of oil in the cargo tanks will increase / decrease depending upon the ambient temperature. This phenomenon can cause either high pressure or near vacuum conditions in the cargo tanks ullage space during the loaded passage. Tank pressures are monitored if tank pressure reach dangerously high levels, tanks will have to be vented. On all ships if the high pressure develop in the ullage spaces of a cargo tanks it is vented through the breather valve on inserted ships if low pressure develops in the ullage space the inert gas low-low pressure alarm is activated this alarm signal may actuate the control systems for starting the inert gas topping up generator which in turn will compensate for the pressure loss in the cargo tanks by introducing inert gas into the ullage space of the cargo tanks. Where such an automatic system is not available the inert gas topping up generator inert gas plant will have to be manually started and the pressure loss in the cargo tanks must be compensated. If the cargo require temperature control during the loading passage (heating or cooling, this must be carried out). 4.3.0 DISCHARGING Before a tanker arrives at the unloading berth there should be an exchange of information between ship and shore. A large portion of the information mentioned in a chapter will also be applicable in the case of a unloading vessels calling port in addition to the aforementioned information the following information will have to be given by the tanks to the shore authorities. Cargo specification Whether or not cargo includes sour crude oil Any other characteristics of the cargo requiring special attention for example aromatic benzene on lead contents or true vapours pressure (where applicable). Flash points (where applicable) for products and their temperature upon arrival Cargo quantities loaded and disposition in ships tanks Quantity and disposition of slopes. Any unaccountable change of ullage in the ships tanks since loadingCENTRE FOR MARITIME EDUCATION AND TRAINING, LUCKNOW

OIL TANKER FAMILIARIZATION COURSE

Water drop in cargo discharge rates Whether tank cleaning or crude oil washing at berth Approximate time or commencement of ballasting into segregated / permanent ballast tanks and cargo tanks.

The terminal must inform the tanker the following ; Order of discharge of cargo acceptable to the terminal. Nominated quantities of cargo to be discharged. Maximum acceptable discharge rates. Maximum pressure acceptable at the ship/shore cargo connection. Any shore booster pumps that may be on stream. Number and sizes of hoses or arms. Any other shore limitations. Communication system for discharge control including the signal for emergency stop.

On the basis of the information exchanged, an operational agreement should be made between the responsible officer on board and the terminal representative covering the following. Names and signature of the ships and shore representative. Cargo distribution on arri