5551256 Process for liquefaction of natural gas

Abstract

There are a number of options of exporting natural gas energy from oil and gas fields to market, including pipelines, liquefied natural gas (LNG), compressed natural gas (CNG), gas to solids (GtS), i.e. hydrates, gas to wire (GtW), i.e. electricity, gas to liquids (GtL), with a wide range of possible products including clean fuels, plastic precursors or methanol and gas to commodity (GtC), such as aluminium, glass, cement or iron. Any gas energy export route requires a huge investment in infrastructure, and long-term ‘fail proof’ contracts, covering perhaps 20 years or more. But which is the best way to monetise the gas? Gas rich countries, such as Trinidad and Qatar are currently in this challenging debate. There could be options for handling niche markets for gas reserves which are stranded (no market) and for associated gas (on- or off-shore) which cannot be flared or re-injected, or for small reservoirs which cannot otherwise be economically exploited. Transportation of natural gas as hydrate or CNG is believed feasible at costs less than for LNG and where pipelines are not possible. The competitive advantage of GtS or CNG over the other non-pipeline transport processes is that they are intrinsically simple, so should be much easier to implement at lower capital costs, provided economically attractive market opportunities can be negotiated to the gas seller. The transport options preferred by governments and companies must not only take the economic risks into account but also consider the negative effects of possible terrorist activity, political changes and trade embargos over long periods of time. In this paper, we cover many of the essential technical points and broad economic pointers needed to enter the discussion of gas rich states which do not need the gas for domestic use, but wish to monetise their reserves by export.