97/01832 Italian refinery gasification project to make electricity, steam, and H2 from tar

Abstract

This chapter discusses the important topics related hydrates including Joule-Thomson expansion, hydrate formation in the reservoir during production, and natural gas formations. When a fluid flows through a valve, its fluid pressure drops adiabatically due to expansion, this is called the Joule-Thomson effect. The Joule-Thomson coefficient for an ideal gas is exactly zero, regardless of the pressure and temperature, while for real fluids, the Joule-Thomson coefficient can be positive or negative. The boundary between the two regions is called the Joule-Thomson inversion curve. This is the temperature and pressure where the Joule-Thomson coefficient is zero. There are three cases where negative Joule-Thomson values may be encountered in engineering practice: a gas at a relatively high temperature, a low temperature liquid, and very high pressure fluids (both gases and liquids). As gas flows from the reservoir into the region of the well bore, the gas expands. If there is no heat transfer with the surrounding formations, this is an isenthalpic process. The flow of the gas through the reservoir is governed by Darcy's law. There are two significant factors in determining the pressure drop in the well flow: friction pressure drop, and hydrostatic head. Another potential application of gas hydrates is for the transportation of natural gas in liquefied form. There are natural occurrences of gas hydrates, such as occurrence of methane hydrates in seabed and occurrence of hydrates in natural gas reservoirs of certain cold regions on Earth, including the arctic regions of Canada and Russia and in Alaska. The possibility of hydrates in outer space has also been speculated.