Natural Gas-The Cinderella Hydrocarbon

Abstract

Abstract When oil was first discovered, the gas released during pressure reduction was considered to be a nuisance byproduct and was usually vented to atmosphere or flared. Natural gas discoveries were often abandoned because the market value of the product was significantly below the cost of production. In the decades which followed producers discovered that natural gas contained a nonrefined condensate which, when blended with crude oil, increased the gasoline yield. Shortly thereafter, propane and butane became more widely used fuels because they were economical and clean burning and could be extracted from natural gas by refrigerated cooling and distillation of the condensed liquids. As the polymer industry evolved, the manufacture of plastics from ethane, propane and butane became economical and the demand for these natural gas components increased. The lower molecular weight components were discovered to be more cost effective then naphtha as feedstock for the production of hydrogen, an essential raw material for the manufacture of fertilizers, and an irreplaceable reagent for the conversion of heavy crude oil to gasoline, diesel, fuel oil and lubricants. When scientists realized that carbon dioxide contributed to the "greenhouse effect" natural gas became the preferred substitute for fuel oil and coal in the electrical power generating plants. The Evolutionary Process The diverse use of natural gas as a fuel and a feedstock for the petrochemical industry has evolved in a "bootstrap" manner. In the early days of the oil industry, drillers were disappointed when natural gas was discovered instead of crude oil. As the number of discoveries increased and the volume of the reserves grew corporations and research organizations focussed on the processing of gas to produce a marketable feed product. Dehydration, liquids recovery, acid gas removal, component separation, transportation and distribution were investigated in an effort to produce an economic alternative to liquid fuels and coal. As profits from the sale of natural gas and recovered liquids increased, technologies were developed to improve the economics of natural gas processing and distribution. In addition, as innovations in the petrochemical industries emerged natural gas producers offered their products as feedstock. Fertilizer, polymer, hydrogen and other manufacturing plants were constructed over natural gas reservoirs or near lucrative markets. During the last century natural gas has become as important as oil or other fossil energy. The producers, contractors, transporters and manufacturers continue to explore novel technologies for the purification of natural gas, recovery of specific components and the transformation of these components into marketable products. Dehydration Natural gas in both gaseous reservoirs and condensate/cured oil formations often coexists with water. This water is transported up the well tubing to the processing facilities at the surface as gases and liquids flow out of the reservoir. Under high pressures and lower temperatures the lower molecular weight hydrocarbons form crystalline structures called hydrates. These structures, comparable to snow or ice, may accumulate in well tubing or pipelines and can restrict or completely obstruct the flow. Hydrates may form at temperatures above the freezing point of water.