Presentation on theme: "3.3.1 Gas Utilities Jesse Sopko, Don(Wilton) Jacobson, Brooke Adams, Hali Perkins, Chris Claypool."— Presentation transcript:
3.3.1 Gas Utilities Jesse Sopko, Don(Wilton) Jacobson, Brooke Adams, Hali Perkins, Chris Claypool
History of Gas Natural gas formed over millions of years ago from decaying plant and animal matter. As plant and animals died, their remains mixed and layered with water, sand, and mud. Over time, the mud and sand sediment built up and formed into rock, trapping the remains underground where the heat and pressure changed the matter within the rock into gas. 1800s, natural gas was used almost exclusively as a fuel for lamps In 1855, Robert Bunsen invented a burner that mixed air with natural gas. The "Bunsen burner" showed how gas could be used to provide heat for cooking and warming buildings. It took the construction of pipelines to bring natural gas to new markets. First lengthy pipelines was built in 1891 -it was 120 miles long and carried gas from fields in central Indiana to Chicago - there were very few pipelines built until after World War II in the 1940s.
History of Gas Cont. Improvements in metals, welding techniques and pipe making during the War made pipeline construction more economically attractive. Industrial users use almost half of the gas produced in the U.S. A large portion is also used in homes for heating, lighting, and cooking. Naturally occurring natural gas was discovered and identified in America as early as 1626, when French explorers discovered natives igniting gases that were seeping into and around Lake Erie. In 1821, William Hart dug the first successful natural gas well in the U.S. In 1836, the City of Philadelphia created the first municipally owned natural gas distribution company. Today, U.S. public gas systems number more than 900, and the Philadelphia Gas Works is the largest and longest operating public gas system in the U.S.
Transmission/ Distribution Gas is transported by main lines across the country, and trucks by compressing the natural gas in tubes on the trailers. Gas lines can be from 1/2in for our house or 4ft. In diameter Many natural gas wells are on private property so a company pays a royalty and the owner gets an allowance per year of free gas. Many gas lines are at 200 to 1500psi (Pounds per Square Inch). There is many stations that check the gas pressure at several points in its journey.
Measuring Normally measured in cubic feet. 1,000 cubic feet of natural gas is approximately enough to meet the natural gas needs of an average home (space-heating, water-heating, cooking, etc.) for four days. In 2009, the average American home consumed 70,500 cubic feet of natural gas (or 72.6 million Btu). On a daily basis, the average U.S. home used 193 cubic feet of natural gas. Most natural gas household bills display the amount of natural gas consumed by the 'therm' (100,000 Btu) or in hundreds of cubic feet (100 cubic feet - 1 Ccf). Looking at larger quantities, 1 billion cubic feet (Bcf) of natural gas is enough to meet the needs of approximately 10,000 - 11,000 American homes for one year. 5 trillion cubic feet of natural gas is enough to meet the needs of 5 million households for 15 years.
Typical Composition of Natural Gas Methane CH 4 70-90% Ethane C2H6C2H6 0-20% Propane C3H8C3H8 Butane C 4 H 10 Carbon Dioxide CO 2 0-8% Oxygen O2O2 0-0.2% Nitrogen N2N2 0-5% Hydrogen sulphide H2SH2S0-5% Rare gases A, He, Ne, Xetrace
Sizing Requirements The top of the conduit must be buried deep enough to allow for PSEs required minimum depth of cover over the gas service line at final grade. A minimum of 24 inches of cover is required for commercial/industrial service lines that are1-1/4- inch or larger pipe. Use yellow or white Schedule 40 PVC for a gas service. You must use conduit that has a smooth wall and is not perforated. The markings on the conduit shall not contain any reference to any other utilities (such as water or sewer). It is preferable that directional changes in the service route be at 90 degrees. It is recommended that the combined degrees of bend do not exceed 180 degrees. Gas Service SizeMin. Bending RadiusMin. Conduit Diameter 1-1/4 Inches48 Inches3 Inches 2 Inches60 Inches4 Inches 113 Inches6 Inches
Sizing Requirements Cont. PVC conduit should extend to the work pits, but stop 4 feet shy of the building wall and 4 feet shy of the gas main stub at the front property line. Dig to within 1 foot of the gas stub marker at the front property line. Do not expose gas pipe or stub. If accidentally exposed, cover the gas line stub with a minimum of12 inches of sand. The trench should be left open at both ends for PSE to install the service. A 4-foot by 4-foot work pit opening is recommended. Conduit ends should be sealed shut and clearly marked using a piece of conduit or 2-inch by 4-inch stake marked Gas. Use soil backfill that is free from construction debris, sharp rocks, glass, frozen clods, and rocks larger than 10 inches in diameter.