An oil tanker , also known as petroleum tanker , is a ship designed for the transportation of bulk oil or its products. There are two basic types of oil tankers: crude oil tankers and product tankers . Crude oil tankers transfer large amounts of crude oil from the extraction point to the refinery. For example, transferring crude oil from oil wells in Nigeria to oil refineries on the coast of the United States. Tanker products, generally much smaller, are designed to move refined products from refineries to a point near the consumer market. For example, moving petrol from refineries in Europe to consumer markets in Nigeria and other West African countries.
Oil tankers are often grouped according to their size as well as their work. Class sizes range from inland or coastal tankers from several thousand metric tons of deadweight (DWT) to giant ultra-large giant aircraft (ULCCs) of 550,000 DWT. The tanker displaces about 2,000,000,000 metric tons (2 ÃÆ' - 10 9 ton short) oil every year. Second only to pipelines in terms of efficiency, the average cost of oil transportation by tankers amounts to only two or three US cents per 1 gallon US (3.8 L).
Some special types of oil tankers have evolved. One of them is a naval filling oiler, a tanker that can move the ship moving. The combination of bulk oil carriers and permanently moored floating storage units are two other variations on the standard oil tanker design. Oil tankers have been implicated in a number of destructive and high profile oil spills. As a result, they are subject to strict design and operational rules.
Video Oil tanker
Histori
Oil transport technology has evolved alongside the oil industry. Although humans used oil to reach prehistoric, modern commercial exploitation first dates back to [[J]. In the 1860s, the Pennsylvania oil field became a major supplier of oil, and an innovation center after Edwin Drake had hit oil near Titusville, Pennsylvania. Large ships and barges were originally used to transport Pennsylvania oil in 40-US-gallon (150Ã, l) wooden barrels. But transport with barrel has some problems. The first problem is weight: thweighed  £ 64 (29 kg), representing 20% ​​of the total weight of the full barrel. Another problem with barrels is their cost, their leakage tendencies, and the fact that they are generally only used once. The cost was significant: for example, in the early years of the Russian oil industry, barrels contributed half the cost of petroleum production.
Initial design
In 1863, two sailing tankers were built on the Tyne River of England. This was followed in 1873 by the first oil tanker, Vaderland , built by the Palmers Shipbuilding and Iron Company for Belgian owners. The use of the vessel is limited by the U.S. authority. and Belgium citing security concerns. In 1871, the Pennsylvania oil fields made use of oil tank barges and cylindrical tank cars similar to those used today.
Modern oil tankers
The modern oil tankers developed in the period from 1877 to 1885. In 1876, Ludvig and Robert Nobel, Alfred Nobel's brother, founded Branobel (short for the Nobel Brothers) in Baku, Azerbaijan. It was, at the end of the 19th century, one of the largest oil companies in the world.
Ludvig was a pioneer in the development of early oil tankers. He first experimented with carrying large amounts of oil on a single-hulled barge. Turning his attention to a self-propelled tank tank, he faces a number of challenges. The main concern is keeping the cargo and smoke away from the engine room to avoid a fire. Other challenges include allowing cargo to expand and contract due to temperature changes, and provide a method for tank ventilation.
The first successful oil tanker was Zoroaster , carrying 242 tons of kerosene cargoes in two iron tanks connected by pipes. One tank is advancing from the midships engine room and the other is aft. The vessel also featured a set of 21 vertical watertight compartments for extra buoyancy. The vessel has an overall length of 184 feet (56 m), a 27 foot (8.2 m) tin, and a 9 foot (2.7 m) draft. Unlike then the Nobel tanker, the Zoroaster design was built small enough to sail from Sweden to the Caspian via the Baltic Sea, Lake Ladoga, Lake Onega, Rybinsk and Mariinsk Canals and the Volga River.
In 1883, the design of an oil tanker took a big step forward. Working for the Nobel company, British engineer Colonel Henry F. Swan designed a set of three Nobel tanker ships. Instead of one or two large handles, the Swan design uses some wide stretching grips, or beams, from the ship. The handle is further divided into ports and right portions with elongated bulkheads. The previous designs suffered from stability problems caused by free-surface effects, where an oil spill from side to side can cause the ship to reverse. But this approach divides the vessel's storage space into smaller tanks virtually eliminating free surface problems. This approach, almost universal today, was first used by Swan on the tanker Nobel
Others point to GlÃÆ'¼ckauf , another design from Colonel Swan, as the first modern oil tanker. It adopted the best practice of the previous oil tanker design to create a prototype for all subsequent vessels of its kind. This is the first steam-powered tanker in the world and is the first vessel in which oil can be pumped directly into the hull instead of being loaded into casks or drums. It was also the first tanker with horizontal partition; Its features include a cargo valve that can be operated from the deck, cargo main pipes, steam ducts, cofferdams for added security, and the ability to fill the tanks with water reply when the water is empty. The ship was built in England. and purchased by Wilhelm Anton Riedemann, an agent for Standard Petroleum Company along with some of his sister ships. After GlÃÆ'¼ckauf disappeared in 1893 after a mist, Standard Oil bought his brother's ship.
Asian trade
The 1880s also saw the beginnings of Asian oil trade. The idea that led Russia's oil to the Far East through the Suez Canal was the idea of ​​two people: the importer Marcus Samuel and the owner of the vessel/broker Fred Lane. The previous offer to move oil through the channel has been rejected by the Suez Can Company because it is too risky. Samuel approached the problem in a different way: asked the company for a tanker specification to be allowed through the channel.
Armed with the company's channel specifications, Samuel ordered three tankers from William Gray & amp; Company in the north of England. Named Murex , Conch and Clam , each has a capacity of 5.010 ton long deadweight. These three ships are the first tankers of Tank Syndicate, the forerunner of the current Royal Dutch Shell company.
With facilities set up in Jakarta, Singapore, Bangkok, Saigon, Hong Kong, Shanghai, and Kobe, the new Shell company is poised to become Standard Oil's first challenger in the Asian market. On August 24, 1892, Murex became the first tanker to pass through the Suez Canal. By the time Shell joined Royal Dutch Petroleum in 1907, the company had 34 steam-driven oil tankers, compared with four oil steamers-the Standard Oil case and 16 sailing tankers.
Supertanker Era
Until 1956, tankers were designed to navigate the Suez Canal. This size limitation became less of a priority after the canal closure during the Suez Crisis of 1956. Forced to move oil around the Cape of Good Hope, the shipowners realized that larger tankers were the key to more efficient transport. While the typical World War II T2 tanker is 532 feet (162 m) in length and has a capacity of 16,500 DWT, the ultra-large (ULCC) aircraft carrier built in the 1970s over 1,300 feet (400 m) long and has a capacity of 500,000 DWT. Several factors encourage this growth. Middle East hostilities that disrupt traffic through the Suez Canal contribute, as does the nationalization of the Middle East oil refineries. Fierce competition among ship owners also plays a role. But apart from these considerations are simple economic benefits: the bigger the oil tankers, the cheaper the crude oil can move, and the better it can help meet the increasing demand for oil.
In 1955, the world's largest supertanker was 30,708 GRT and 47,500 LTT DWT: SS Spyros Niarchos was launched that year by Vickers Armstrongs Shipbuilders Ltd in the UK for Stavros Niarchos.
In 1958, the king of the United States ship Daniel K. Ludwig broke the record 100,000 tonnes of massive displacement. His Universe Apollo displaced 104,500 tons in length, a 23% increase from the previous record holder, Universe Leader which also belongs to Ludwig.
The world's largest supertanker was built in 1979 at the Oppama shipyard by Sumitomo Heavy Industries, Ltd., dubbed Seawise Giant . The vessel was built with a capacity of 564.763 DWT, an overall length of 458.45 meters (1,504.1 ft) and a draft of 24.611 meters (80.74 ft). He has 46 tanks, 31,541 square meters (339,500 sq ft) from the deck, and on the concept of his full load, can not navigate the Channel.
Seawise Giant was renamed Happy Giant in 1989, Jahre Viking in 1991, and Knock Nevis on 2004 (when he was converted into a permanent mooring storage tanker). In 2009 it was sold for the last time, renamed Mont , and deleted.
In 2011, two of the world's largest work supertankers were the IT-class IT-IT supertankers and IT Oceania . These ships were built in 2002 and 2003 as Hellespont Alhambra and Hellespont Tara for Hellespont Greece Steamship Company. Hellespont sold these vessels to the Overseas Shipholding Group and Euronav in 2004. Each sister ship has a capacity of over 441,500 DWT, an overall length of 380.0 meters (1,246.7 feet) and a cargo capacity of 3,166,353 barrels (503,409,900 liters ). They are the first ULCC double-dipped. To distinguish them from smaller ULCCs, these ships are sometimes assigned the size of V-Plus .
With the exception of pipes, tankers are the most effective way to move oil today. Worldwide, tankers carry around 2 billion barrels (3.2 ÃÆ' - 10 11 Ã, l) each year, and transport costs with tankers are only US $ 0 , 02 per gallon at the pump.
Maps Oil tanker
Size category
In 1954 Shell Oil developed an average haulage rating system (AFRA) that classifies tankers of different sizes. To make it an independent instrument, Shell consults with the London Tanker Brokers' Panel (LTBP) . Initially, they divided the group as General Goals for tankers under 25,000 deadweight tonnes (DWT); Medium Term for vessels between 25,000 and 45,000 DWT and Large Reach for larger vessels greater than 45,000 DWT. The ships became larger during the 1970s, which prompted the re-enrichment.
The system was developed for tax reasons because the tax authorities wanted proof that internal billing records were correct. Before the New York Mercantile Exchange began trading in crude oil futures in 1983, it was difficult to determine the exact price of oil, which could change with each contract. Shell and BP, the first company to use the system, abandoned the AFRA system in 1983, followed by US oil companies. However, this system is still in use today. In addition, there is a flexible market scale, which takes a typical route and many 500,000 barrels (79,000 m 3 ).
Oil tanker traders bring a variety of hydrocarbon liquids ranging from crude oil to pure oil products. Their measurements are measured in deadweight metric tons (DWT). Crude oil carriers are the largest, ranging from 55,000 DWT Panamax ships to ultra-large crude carriers (ULCCs) of more than 440,000 DWT.
Smaller tankers, ranging from under 10,000 DWT to 80,000 DWT Panamax ships, generally carry petroleum-processed products, and are known as product tankers. The smallest tanker, with a capacity below 10,000 DWT generally works in the waters near the coast and inland. Although they were in the past, smaller Aframax and Suezmax vessels are no longer considered supertankers.
Chuan Yeu (VLCC and ULCC)
"Supertanker" is the largest tanker, and the largest man-made cellular structure. They include very large crude oil carriers (VLCC) and ULCCs with a capacity of over 250,000 DWT. These ships can carry 2,000,000 barrels (320,000 m 3 ) oil/318,000 metric tons. By comparison, the UK consumed about 1.6 million barrels (250,000 m 3 ) of oil per day in 2009. The ULCCs, commissioned in the 1970s, were the largest vessels ever built, but the longest that have been deleted. In 2013 only a few ULCCs are still operating, none of which are more than 400 meters in length.
Due to its large size, supertankers often can not enter the full port. These ships can take their cargo on offshore platforms and single mooring points. At the other end of the journey, they often pump their cargo to smaller tankers at designated landing points offshore. The supertanker route is usually long, which requires them to stay at sea for a long time, often about seventy days at a time.
Chartering
The act of hiring a ship to transport cargo is called a charter. Tankers are hired by four types of charter agreements: travel charter, time charter, bareboat charter, and affreightment contract. In a travel charter, the tenant hires a vessel from the loading port to the disposal port. In a certain time, the ship was hired for a certain period of time, to make the voyage as did the tenant. In bareboat charters, charterers act as operators and ship managers, taking on responsibilities such as providing crews and maintaining vessels. Finally, in an affreightment or COA contract, the lessee determines the total volume of cargo to be carried over a certain period of time and in certain sizes, for example COA can be designated as 1 million barrels (160,000 m 3 ) of JP-5 in one year time in 25,000-barrel shipment (4,000 m 3 ). A complete chartering contract is known as a charter party.
One of the key aspects of any charter party is the shipping rate, or the price specified for cargo transport. The chartered tanker charter fares are determined in one of four ways: by lump sum rate, on a per tonne basis, with an equivalent level charter time, or with a Worldscale rate. In the price setting at once, the fixed price is negotiated for certain cargo shipments, and the ship owner/operator is responsible for paying all port charges and other travel expenses. The tariff setting per ton is widely used in chemical tanker rentals, and is different from the lump sum rates in the port fees and the travel expenses are generally paid by the lessee. Time charter settings specify daily rates, and port fees and travel expenses are also generally paid by the lessee.
Normal Frequency Tanker Scale Worldwide, often referred to as the World Scale, was established and organized jointly by the London and New York Class World Associations. The world scale sets the base price to bring a ton of products between the two ports in the world. In Worldscale negotiations, the operator and the lessee will determine the price based on Worldscale percentage rate. The base rate is expressed as WS 100. If a party charter is set at 85% of the Worldscale rate, it will be declared as WS 85. Similarly, a designated lease party of 125% of the Worldscale rate will be declared WS 125.
The current market
In 2007, the charter market continues to fluctuate in all tanker sectors. The market is influenced by variables such as oil supply and demand and supply and demand of oil tankers. Certain variables include winter temperatures, excess tanker tonnage, supply fluctuations in the Persian Gulf, and disruptions in refinery services.
In 2006, sustained increases in oil prices have only limited impact on demand. This is a good year in all segments of the tanker market segment, but not as good as 2004 and 2005. Amid high oil prices, geopolitical tensions, and fears of oil supply disruptions, increasing demand is a major driving force in tankers. market shipment for this year. As demand grew moderately in the United States and Western Europe, economic expansion such as China sparked exponential demand growth. Despite this strength, each of the five tanker indices declined during 2006. The demand for product tankers increased in 2006 due to the economic expansion in Asia, especially China and India; however, the average timeframe of equivalent revenue planners for these vessels decreased compared to two years earlier..
In 2006, time-charters tended toward the long-term. Of the time charter executed in that year, 58% for a period of 24 months or more, 14% for the period of 12 to 24 months, 4% were from 6 to 12 months, and 24% for periods less than 6 months. Average average one-year lease rates for 5-year-old tankers of 280,000 metric tons of deadweight vary from $ 56,500 per day in December 2005 to $ 53,000 per day in September 2007 with a high of $ 64,500 per day in September 2006.
The first half of 2007 was relatively strong, but at the second half level it dropped significantly. A sudden increase in oil production, longer transportation routes, and slow evaporation due to high bunker prices lead to tonnage shortages by the end of the year. Overnight, the VLCC rate rose from $ 20,000 per day to $ 200- $ 300,000 per day, and even higher amounts were recorded.
From 2003, demand for new vessels began to grow, so that in 2007 in the backlog order record for shipyards, exceeded their capacity with the rise in price of new development as a result. This results in a flood of vessels as demand falls due to the weakening global economy and dramatically reduces demand in the United States. The rate of charter for a very large crude carrier, carrying two million barrels of oil, has peaked at $ 309,601 per day in 2007, and has dropped, by 2012, to $ 7,085 per day, well below the operating cost of ships this. As a result, some tanker operators put their boats. Prices rose significantly in 2015 and early 2016, but new tanker shipments are projected to keep prices under control.
Pemilik armada kapal tanker minyak besar termasuk Teekay Corporation, A P Moller Maersk, DS Torm, Frontline, MOL Tankship Management, Overseas Shipholding Group, dan Euronav.
Karakteristik armada
In 2005, oil tankers made up 36.9% of the world's fleet in terms of deadweight tonnage. Total tonnage of total world oil tankers has increased from 326.1 million DWT in 1970 to 960.0 million DWT in 2005. Combined tonnage of oil tanker and aircraft carrier, representing 72.9% of the world's fleet.
Movement of cargo
In 2005, 2.42 billion metric tons of oil were shipped by tankers. 76.7% of this is crude oil, and the rest consists of pure oil products. This amounted to 34.1% of all seafaring trades for the year. By combining the carrying amount with distance traveled, the oil tanker moved 11,705 billion metric tons of oil in 2005.
By comparison, in 1970 1.44 billion metric tons of oil were shipped by tankers. This amounted to 34.1% of all seafaring trade for the year. In terms of the quantity carried and the distance traveled, the oil tanker moved 6.487 billion metric tons of oil in 1970.
The United Nations also maintains statistics on the productivity of oil tankers, expressed in metric tons performed per deadweight metric ton and metric tonnes of cars per metric ton of deadweight. In 2005, for every 1 DWT oil tanker, 6.7 metric tons of cargo was brought. Similarly, every 1 DWT oil tanker is responsible for 32,400 metric-ton miles of wagons.
The main loading ports in 2005 are located in West Asia, West Africa, North Africa and the Caribbean, with 196.3, 196.3, 130.2 and 246.6 million metric tons of cargo loaded in the region. Major disposal ports are located in North America, Europe, and Japan with 537.7, 438.4, and 215.0 million metric tons of cargo being discharged in the region.
Flag country
International law requires that each merchant ship is registered in a country, called a flag country. A flag state regulatory ship exercises control over vessels and is required to regularly inspect, certify ship and crew equipment, and issue security and pollution prevention documents. In 2007, United States Central Intelligence statistics calculated 4,295 oil tankers 1,000 tons deadweight (DWT) or greater worldwide. Panama is the world's largest flagging country for oil tankers, with 528 from ships in the registry. Six other flag countries have more than 200 registered oil tankers: Liberia (464), Singapore (355), China (252), Russia (250), Marshall Islands (234) and Bahamas (209). Flags of Panama, Liberia, Marshall and the Bahamas are open registrars and considered by the International Transportation Workers Federation to be the flag of convenience. By comparison, the United States and Britain have only 59 and 27 registered oil tankers, respectively.
Ship life cycle
In 2005, the average age of oil tankers worldwide was 10 years. Of these, 31.6% are under 4 and 14.3% are over 20 years of age. In 2005, 475 new oil tankers were built, generating 30.7 million DWT. The average size for this new tanker is 64,632 DWT. Nineteen of them are VLCC size, 19 are suezmax, 51 are aframax, and the rest are smaller designs. By comparison, 8.0 million DWT, 8.7 million DWT, and 20.8 million DWT oil tanker capacities were built in 1980, 1990, and 2000 respectively.
Ships are generally removed from the fleet through a process known as scrapping. Shipowners and buyers negotiate scrap prices based on factors such as empty vessel weight (called tonne light displacement or LDT) and prices in the scrap metal market. In 1998, nearly 700 vessels undertook the demolition process on ships in places like Alang, India and Chittagong, Bangladesh. In 2004 and 2005, 7.8 million DWT and 5.7 million DWT respectively from oil tankers were abolished. Between 2000 and 2005, the capacity of oil tankers dumped annually ranged between 5.6 million DWT and 18.4 million DWT. In this same time period, tankers accounted for between 56.5% and 90.5% of the total tonnage of ships dumped in the world. In this period the average age of oil tankers discharged has ranged from 26.9 to 31.5 years.
Price of ship
In 2005, new oil tanker prices in the range of 32,000-45,000 DWT, 80,000-105,000 DWT, and 250,000-280,000 DWT were US $ 43 million, $ 58 million, and $ 120 million. In 1985, these ships would cost $ 18 million, $ 22 million, and $ 47 million respectively.
Oil tankers are often sold for traces. In 2005, 27.3 million DWT of sold oil tankers were used. Some representative prices for that year include $ 42.5 million for tanker 40,000 DWT, $ 60.7 million for 80,000-95,000 DWT, $ 73 million for 130,000-150,000 DWT, and $ 116 million for 250,000-280,000 DWT tankers. For a concrete example, in 2006, Bonheur's subsidiary, First Olsen, paid US $ 76.5 million for Knock Sheen , a 159,899 DWT tanker.
The largest tanker operating costs, the Large Crude Carriers, are currently between $ 10,000 and $ 12,000 per day.
Design the current structure
Oil tankers generally have 8 to 12 tanks. Each tank is divided into two or three independent compartments with front and back cover. The tanks are numbered with one tank to the front. Individual compartments are referred by tank numbers and transverse positions, such as "one port", "three right boards", or "six centers."
Cofferdam is a small, small space that opens between two barriers, to provide protection from heat, fire, or collision. Tankers generally have forward cofferdams and stern charge tanks, and sometimes in between individual tanks. A pumpable room holds all pumps connected to a tanker cargo channel. Some of the larger tankers have two pump chambers. A pump room generally reaches the total vessel area.
Design Hull
The main component of tanker architecture is the design of the hull or outer structure. A tanker with one outermost shell between the product and the ocean is said to be a "single hull". Most newer tankers are "double-hulled", with extra space between the hull and the storage tank. Hybrid designs such as "double-bottom" and "double-sided" combine aspects of single and double winding design. All skinned tanker ships worldwide will be removed in 2026, in accordance with the International Convention for the Prevention of Pollution from Ships, 1973 (MARPOL). The United Nations has decided to end a single gass oil tanker in 2010.
In 1998, the Marine Racecar Board of the National Academy of Science conducted a survey of industry experts on the pros and cons of double-hull design. Some of the advantages of the mentioned double-hull designs include the ease of ballasts in emergency situations, reducing the practice of saltwater ballasts in cargo tanks reducing corrosion, increasing environmental protection, faster, more complete and easier cargo disposal, more efficient tank wash, and protection better in impact and low impact grounding.
The same report lists the following as several weaknesses in the double hull design, including higher development costs, greater operating costs (eg higher channel and port rates), difficulties in tank vents, the fact that the tank is repaid need continuous monitoring and maintenance, increased transverse surfaces, larger surface counts to maintain, the risk of explosions in the double hull space if the steam detection system is not installed, and that cleaning the tank back is more difficult for double hull vessels.
Overall, double-hull tankers are said to be safer than a single hull in a grounding incident, especially when the beach is not too rocky. The security benefits are less clear on larger vessels and in the case of high-speed impacts.
Although the double-hull design is superior in low-energy accidents and prevents spills on small casualties, in high-energy casualties where both hulls are violated, oil can spill over the double hull and into the sea and spills from double tank boats can be much higher designs such as deck deck tankers, Coulombi egg tankers and even pre-MARPOL tankers, such as the latter have lower oil columns and achieve a faster hydrostatic balance.
Inert gas system
The inert gas tanker oil system is one of the most important parts of its design. Fuel oil itself is very difficult to burn, but its hydrocarbon vapor is explosive when mixed with air at a certain concentration. The purpose of this system is to create an atmosphere inside the tank where hydrocarbon oil vapor can not burn.
Since the inert gas is fed into the mixture of hydrocarbon vapor and air, it increases the lower limit of flammability or the lowest concentration at which steam can be ignited. At the same time it reduces the upper flammability limit or the highest concentration at which steam can be ignited. When the total oxygen concentration in the tank reaches about 11%, the flammable upper and lower limits converge and the flammable range disappears.
Inert gas systems deliver air with an oxygen concentration of less than 5% by volume. When a tank is pumped out, it is filled with inert gas and stored in this safe state until the next load is loaded. The exception is in the case when the tank should be inserted. A safe free gas tank is liberated by cleaning the hydrocarbon vapor with inert gas until the hydrocarbon concentration in the tank is below 1%. Thus, since the air replaces the inert gas, the concentration can not rise to a lower, safer flammable limit.
Cargo operations
Operations on oil tankers are governed by best practice bodies and large international legal entities. Cargo can be moved or turned off from oil tankers in several ways. One method is to ship anchored along the pier, connected to a cargo hose or a sea loading arm. Other methods involve mooring into offshore buoys, such as damping a single dot, and making cargo connections through an underwater cargo hose. The third method is by shipping from ship to ship, which is also known as a lighter. In this method, two ships come together in the open ocean and the oil is transferred manifold to the manifold via a flexible hose. Lightering is sometimes used where tankers are loaded too large to enter certain ports.
Preparation pre-transfer
Prior to cargo transfers, the primary officer must develop a transfer plan detailing certain operations such as how much cargo to move, which tanks to clean, and how the vessels will change. The next step before the transfer is a pre-transfer conference. The pre-transfer conference covers issues such as what products to move, the order of movements, names and titles of key persons, information on ship and coastal equipment, critical circumstances of transfers, prevailing regulations, emergency procedures and spill containment, watches and shift settings, and shutdown procedures.
After the conference is complete, the person in charge of the vessel and the person responsible for the beach installation checks the final check list. In the United States, the checklist is called the Declaration of Inspection or DOI. Outside the US, the document is called "Ship/Coast Safety Checklist." The items on the checklist include the appropriate signs and signs displayed, safe ship moorings, language options for communication, security of all connections, that emergency equipment is available, and no repair work is done.
Loading cargo
Loading oil tankers consist mainly of pumping cargo into the ship's tank. When oil enters the tank, steam in the tank must be removed. Depending on local regulations, steam may be released into the atmosphere or discharged back to the pumping station through the steam recovery path. It is also common for vessels to move water ballasts during loading of cargo to maintain the right trim.
The load begins slowly with low pressure to ensure that the equipment is functioning properly and the connection is secure. Then a stable pressure is reached and held up to a "topping-off" phase when the tank is nearly full. Topping off is a very dangerous time in handling oil, and the procedure is handled carefully. The tank gauge is used to inform the person responsible for how much space is left in the tank, and all tankers have at least two independent methods for measuring the tank. When the tanker becomes full, the crew members open and close the valve to direct the flow of the product and maintain close communication with the pumping facility to reduce and ultimately stop the fluid flow.
Unloading cargo
The process of removing oil from tankers is similar to loading, but it has some major differences. The first step in this operation follows the same pre-transfer procedure as used in loading. When the transfer begins, it is a cargo ship pump used to move the product overland. As with loading, the transfer begins with a low pressure to ensure that the equipment is functioning properly and the connection is secure. Then a stable pressure is reached and retained during operation. When pumping, the tank level is carefully monitored and the main locations, such as the connections at the cargo manifold and the ship pumping chamber, are continuously monitored. Under the direction of the responsible person, crew members open and close the valve to direct the flow of the product and maintain close communication with the receiving facility to reduce and ultimately stop the flow of fluids.
Tank cleaning
The tank must be cleaned from time to time for various reasons. One reason is to change the type of product carried in the tank. Also, when the tank should be checked or maintenance should be done inside the tank, it should not only be cleaned, but made gas free .
In most crude oil tankers, a special crude oil washing system (COW) is part of the cleaning process. The COW system circulates parts of the load through a fixed tank cleaning system to remove wax and asphalt deposits. Tanks carrying less viscous cargo are washed with water. Automatic and fixed tank cleaning machines, which clean the tanks with high-pressure water jets, are widely used. Some systems use high-pressure water jets to rotate to spray hot water throughout the internal surface of the tank. When spraying takes place, the liquid is pumped out of the tank.
After the tank is cleaned, as long as it will be prepared to enter, it will be cleaned . Cleaning is done by pumping the inert gas into the tank until the hydrocarbon has been adequately removed. The tank is then the liberated gas normally achieved by blowing fresh air into space with a portable air-powered or water-powered air blower. "Gas freeing" carries the oxygen content of the tank up to 20.8% O2. Buffering an inert gas between fuel and atmospheric oxygen ensures they are never able to ignite. Specially trained personnel monitor the tank atmosphere, often using handheld gas indicators that measure the percentage of hydrocarbons present. After a gas-free tank, it may be further hand-cleaned in a manual process known as mucking. Mucking requires protocols for entry into confined spaces, protective clothing, designated security observers, and possible use of flight respirators.
Usage special oil tanker
Several sub-types of oil tankers have evolved to meet certain military and economic needs. These sub-types include naval fittings, carriers of bulk-oil-bulk combinations, floating storage and offloading units (FSOs) and floating production storage and offloading units (FPSOs).
Shipboard
Charging boats, known as oil ships in the United States and fleet tankers in Commonwealth countries, are ships that can supply oil products to naval vessels while on the go. This process, called recurrent charging, extends the length of time a naval vessel can stay at sea, as well as its effective range. Before charging takes place, naval vessels must enter the harbor or anchor to pick up fuel. In addition to fuel, refueling boats can also send water, ammunition, rations, stores and personnel.
ore-bulk-oil operator
The bulk carrier ore, also known as the combination carrier or OBO, is a ship designed to be capable of carrying wet or dry bulk cargoes. This design is intended to provide flexibility in two ways. Firstly, OBO will be able to shift between dry and wet bulk trade based on market conditions. Secondly, OBO can carry oil on one foot of the voyage and bring back dry bulk, reducing the number of unfavorable weighing voyages to be made.
In practice, the flexibility that allows OBO design has been largely unused, as these ships tend to specialize in bulk or liquid bulk trade. Also, these ships have endemic maintenance issues. On the one hand, due to a less specialized design, OBO suffers more from wear and tear during dry cargo onload than bulk. On the other hand, the components of the liquid cargo system, from pump to valve to pipe, tend to develop problems when experiencing unused periods. These factors have contributed to a steady decline in the number of OBO vessels worldwide since the 1970s.
One of the most famous OBOs is the 180,000 DWT MVÃ, Derbyshire which in September 1980 became the largest British ship ever lost at sea. It sank in a Pacific cyclone carrying iron ore loads from Canada to Japan.
Floating storage unit
Floating storage and offloading units (FSOs) are used worldwide by the offshore oil industry to receive oil from nearby platforms and store them down to be lowered to oil tankers. Similar systems, floating unit storage and storage (FPSO), have the ability to process products while on board. This floating unit reduces oil production costs and offers mobility, large storage capacity, and production versatility.
FPSOs and FSOs are often manufactured from old crude oil tankers, but can be made from the new Shell Espaà ± a first hull of using tankers as an FPSO in August 1977. The former FSO example of an oil tanker is Knock Nevis . These units are usually tethered to the seafloor through a scattered mooring system. Tower-style mooring systems can be used in areas prone to severe weather. This turret system allows rotating units to minimize the effects of ocean waves and winds.
Pollution
Oil spills have a very bad impact on the environment. Crude oil contains polycyclic aromatic hydrocarbons (PAHs) that are very difficult to clean, and last for years in sediments and seas. Continuously exposed marine species of PAHs may exhibit developmental problems, susceptibility to disease, and abnormal reproductive cycles.
With so much oil being carried, modern oil tankers can pose a threat to the environment. As discussed above, the VLCC tanker can carry 2 million barrels (320,000 m 3 ) of crude oil. This amount is about eight times the incidents of Exxon Valdez . In this spill, the ship ran aground and dumped 10.800,000 US gallons (41,000 m 3 ) oil into the sea in March 1989. Despite efforts by scientists, managers, and volunteers of more than 400,000 seabirds, about 1,000 sea ​​otters, and large numbers of fish killed. Considering the volume of oil carried by the sea, however, tanker owners' organizations often argue that the industry's safety record is very good, with only a fraction of the percentage of oil cargo being sown. The International Association of Independent Tanker Owners has observed that "unintentional oil spills in this decade have reached a record low - a third of the previous decade and one-tenth of the 1970s - as the oil transported has more than doubled since the mid- an. "
Oil tankers are just one source of oil spills. According to the US Coast Guard, 35.7% of the volume of oil spilled in the United States from 1991 to 2004 came from tankers (vessels/barges), 27.6% of facilities and other non-vessels, 19.9% ​​of non- ship tanks, and 9.3% of pipelines; 7.4% of the mystery spill. Only 5% of the spill actually comes from oil tankers, while 51.8% comes from other types of vessels. Detailed statistics for 2004 shown in the table below show the tankers responsible for less than 5% of the total spill count but more than 60% of the volume. Tanker spills are much rarer and much more serious than spills from non-tank boats.
The International Tanker Owner's Polling Federation has tracked 9351 accidental spills that have occurred since 1974. According to this study, most spills are generated from routine operations such as cargo loading, cargo removal, and fuel oil pickup. 91% of small operational oil spills, yielding less than 7 metric tons per spill. On the other hand, spills resulting from accidents such as collisions, groundings, gastric failures, and explosions are much greater, with 84% of these involving losses of over 700 metric tons.
Following the spill of Exxon Valdez , the United States passed the 1990 Oil Pollution Act (OPA-90), which excluded a single tank ship of 5,000 gross tons or more of US waters from 2010 onwards, apart. of people with double bottom or double side, who are allowed to trade to the United States until 2015, depending on their age. After the sinking of Erika (1999) and Prestige (2002), the EU passed its own strict anti-pollution package (known as Erika I, II, and III), which also required all tankers entered their waters to be doubled in 2010. Erika's packages are controversial because they introduce a new legal concept of "serious negligence".
Air pollution
Source of the article : Wikipedia
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