Gas. 1 Flashcards
The amount of pressure in a pipeline is measured in
pounds per square inch.
The fundamental principle of the natural gas delivery system is:
Gas flowing from higher to lower pressure.
From the well, the natural gas goes into “gathering” lines, which are
like branches on a tree, getting larger as they get closer to the central collection point.
From the gathering system, the natural gas moves into the
transmission system, which is composed of about 272,000 miles of high-strength steel pipe ranging from 20 inches to 42 inches in diameter.
These large transmission lines for natural gas can be compared to
the nation’s interstate highway system for cars. They move large amounts of natural gas thousands of miles from the producing regions to local distribution companies (LDCs).
The pressure of gas in each section of line typically ranges from
200 pounds to 1,500 pounds per square inch, depending on the type of area in which the pipeline is operating.
Compressor stations are located approximately
every 50 to 60 miles along each pipeline to boost the pressure that is lost through the friction of the natural gas moving through the steel pipe.
Natural gas moves through the transmission system at up to
30 miles per hour, so it takes several days for gas from Texas to arrive at a utility receipt point in the Northeast.
The amount of gas in the pipe is called the “_________.”
linepack.
A 50-mile section of 42-inch transmission line operating at about 1,000 pounds of pressure contains about 200 million cubic feet of gas – enough to power a kitchen range for more than 2,000 years.
By raising and lowering the pressure on any pipeline segment, a pipeline company can
use the segment to store gas during periods when there is less demand at the end of the pipeline.
When the natural gas in a transmission pipeline reaches a local gas utility, it normally passes through a “___________”
gate station.
Gate stations serve three purposes. First, they
reduce the pressure in the line from transmission levels (200 to 1,500 pounds) to distribution levels, which range from ¼ pound to 200 pounds.
Second use of a Gate Station is to
Add an odorant, the distinctive sour scent associated with natural gas, is added, so that consumers can smell even small quantities of gas.
The third use of a Gate Station is
to measure the flow rate of the gas to determine the amount being received by the utility.
