Adventures in Energy
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Although natural gas and crude oil often can be found in the same location, they take completely different routes from the wellhead to you, the consumer. While crude oil and refined products can travel through a chain of pipelines, tanker ships, trucks and the like, 99 percent of natural gas makes the journey entirely through pipelines made of durable carbon steel. This makes it important to bring recovered natural gas into line with market specifications before it enters the main interstate pipeline system. The natural gas used to cook our food and/or heat and cool our homes is 90 percent clean-burning methane, the simplest form of hydrocarbon. But that's not the case for natural gas as it comes out of the ground. Depending on the location of the well and the geologic conditions that created the gas in the first place, contaminants such as water, sulfur and natural gas liquids (including ethane, propane and butane) may be present. So-called “gathering pipelines” collect natural gas from wells in a given region and deliver it to local processing plants. The processed gas then enters the interstate pipeline distribution system.

Dehydration

Natural gas often comes out of the ground mixed with water vapor. This "wet gas" can be separated using two primary methods:  Glycol dehydration – Wet gas moves through an inlet pipe into a tank called a "contactor." A rounded cap over the inlet pipe forces the gas to flow down into a pool of glycol solution at the bottom of the tank. Glycol has a strong affinity for water, so the water molecules from the wet gas bond to the glycol molecules in the solution. The vapor-free natural gas is collected from the top of the contactor.  Because water boils at 212F and glycol doesn't boil until 400F, simple heating is all that is required to vaporize the captured water so the glycol solution can be reused.  Solid-desiccant dehydration - This method is typically more effective than glycol dehydration, but requires higher volumes of natural gas moving under high pressure. The wet gas is pumped downward through a tower filled with a solid desiccant (drying agent). The desiccant attracts and binds the water molecules so that only dry gas flows out the bottom of the tower.  When the desiccant has captured all the water it can, operators flush the tower with heated gas that re-vaporizes the water molecules, thereby "reactivating" the desiccant.

Oil Tankers

Advances in exploration and production have helped to locate and recover a supply of oil and natural gas from major reserves across the globe. At the same time, demand for petroleum-based products has grown in every corner of the world. But supply and demand are rarely concentrated in the same place. Transportation therefore is vital to ensuring the reliable and affordable flow of petroleum we all count on to fuel our cars, heat our homes and improve the quality of our lives.  Tankers and pipelines are proven, efficient and economical means of connecting petroleum supply and demand. Supply-end pipelines carry crude oil from well to a loading terminal at a port. Tankers then carry the crude oil directly to demand-side pipelines that connect to the refineries that convert the raw material into useful products. Select the dates at left to see how the shipping of crude oil has evolved over time into the high-tech, reliable and environmentally sound system we enjoy today.

• 1885 - The United States and Russia were the major producers of crude oil, most of which was refined into kerosene. Invented in 1854, kerosene was in demand because it burned cleaner and brighter than other lamp fuels, such as whale oil. Kerosene from American refineries was soon crossing the Atlantic to meet growing demand in Europe.The first oil exports crossed the ocean aboard all-purpose sailing ships, stored in the same wooden barrels usually used for wine.Some of these ships were later outfitted with large-volume tanks to increase their carrying capacity.Eventually, ships were built specifically to carry oil and petroleum products. The Glückauf, launched in 1886 and featuring an extra-strong hull, reinforced construction and specialized oil-handling systems, is considered the forerunner of modern oil tankers.

• 1955 - The automobile revolutionized American life in the first half of the 20th Century and created increased demand for gasoline. Oil also helped power rebuilding efforts after two destructive world wars. To ensure adequate supply to meet the growing demand, exploration and recovery efforts focused on new sources in the Middle East and Canada.The need to deliver more oil called for larger tankers. Early iron and steel vessels were built using the same principles as wooden sailing ships -- lateral framing pieces attached to a single keel -- but problems with weight distribution and structural rigidity limited tankers to 82,000-barrel capacity. In 1908, Sir Joseph Isherwood patented a new shipbuilding technique that included frames and bulkheads running front-to-back and used the ship's floors to increase rigidity. By the early 1950's, "supertankers" built using a modified version of Isherwood's system had capacities of more than 280,000 barrels.

• 2002 - In the latter half of the 20th Century, advances in exploration and recovery technology opened up new supplies of oil and natural gas all around the world. To make long-distance transportation more cost-effective, tanker manufacturers developed "very large capacity carriers," or VLCCs, that can carry more than 1,400,000 barrels of crude oil.Larger tankers conserve energy and reduce transportation costs. That's because although it requires more energy to power a larger ship, the rate of increase is less than the rate of increase in carrying capacity. For example, 16,000 horsepower are needed to drive a 420,000-barrel tanker, while 42,500 horsepower can propel a 1,820,000-barrel ship at the same speed. That means it takes less than three times the power to deliver more than four times the oil, reducing total energy consumption and saving fuel.

Refining Oil

Every barrel of crude oil holds remarkable potential: to keep us warm, to keep us on the go and to provide the building blocks for countless products we depend on every day.  The job of the refinery is to unleash that potential by sorting and improving the hydrocarbons within the crude. Gasoline, propane, jet fuel, heating oil and petrochemicals are just some of the specially formulated products leaving the refinery.  Technicians in a central control room can fine-tune refinery operations to produce the desired mix of products. For example, the same barrel of crude can be processed to yield more heating oil in winter or gasoline in summer driving season. Within the refining system, nothing is wasted and the byproducts from one process often are integral to another.

Oil and Natural Gas in Your Life

Oil and natural gas play important roles in our daily lives, and in some ways you might not expect: Hydrocarbons are the building blocks of vital products such as plastics, pharmaceuticals and more. Cleaner-burning fuels are contributing to improved air quality. And fossil fuels may prove to be the ideal source of hydrogen for clean power generation.