Autothermal reforming (ATR) combines thermal POX and the reforming of low-sulfur natural gas in a single reactor. The process was developed to produce syngas from natural gas for making methanol, ammonia, and Fischer-Tropsch liquids, due to its production of a H2/CO ratio of 2:1. The ATR reactor is a refractory-lined pressure vessel with a combustion chamber, burner, and catalyst bed (see figure below).
“We will be updating our decades-old standards to encourage the kind of infrastructure and technology that companies I’ve met with in the Bakken and Permian basins [in North Dakota and Texas, respectively] have demonstrated can reduce harmful emissions and capture the natural gas as a source of energy and revenue for the American people,” she said.
This is thefirst of several planned "FLOATING LIQUID NATURAL GAS FACILITIES" beingbuilt for SHELL, Europe’s largestoil company, The Anglo-Dutch company, based in The Hague.
Liquefied petroleum gases are the light hydrocarbon fraction of the paraffin series, derived from refinery processes, crude oil stabilisation plants and natural gas processing plants comprising propane (C3H8) and butane (C4H10) or a combination of the two. They could also include propylene, butylene, isobutene and isobutylene. LPG are normally liquefied under pressure for transportation and storage.
Only about 6 percent of the world’s known natural gas fields are big enough to sustain a conventional, large-scale GTL plant. In contrast, smaller scale GTL plants are designed to operate efficiently and economically when producing between 1,500 and 15,000 bbl/d of liquid fuels, which requires 15,000-150,000 MMBtu of gas a day. Instead of the $20 billion estimated capital cost for a mega-scale plant, a 2,500 bbl/d GTL plant costs around $250 million, or roughly $100,000 for every barrel of installed daily capacity.
This review examines the technology and economics of producing liquid hydrocarbon fuels from natural gas by a process that has been developed and licensed by Syntroleum Corporation of Tulsa, Oklahoma. The Syntroleum process consists of three major reaction steps: (1) Natural gas is first partially oxidized with air to produce synthesis gas (syngas); (2) the syngas is then reacted in a Fischer-Tropsch (F-T) reactor to polymerize it into liquid hydrocarbons of various carbon-chain lengths; and (3) the heavy fraction of the F-T products is separated and cracked back to transportation fuels in a hydrocracking reactor. The liquid synthetic fuels (synfuels) produced are middle distillates consisting of naphtha, kerosene, and diesel.
The Fischer-Tropsch reactors used in smaller scale gas-to-liquids plants may be configured to efficiently produce 1,500-15,000 barrels a day of liquid fuels, consuming 15,000-150,000 MMBtu of natural gas in the process. The reactors employ microchannel FT technology and a superactive catalyst to intensify chemical reactions in order to overcome mass and heat transfer problems inherent in conventionally-sized GTL plants.
Chemical processes for converting natural gas into useful liquid products have been around for a long time. The two main established chemical processes that do this are GTL and MTG, or methanol-to-gasoline. Both processes start with reforming natural gas into synthesis gas (a mixture of hydrogen and carbon monoxide), but it is the GTL process that has been more broadly practiced. Royal Dutch Shell, for example, has a 140,000 barrel-a-day operation in Qatar, where Sasol also has a 35,000 bbl/d plant.
GTL makes sense in the new gas-rich world. Natural gas, itself, is a poor substitute for most transportation fuel needs; infrastructure challenges inhibit the widespread adoption of compressed and liquefied natural gas for mainstream automotive purposes. In contrast, GTL is designed to make exactly the liquid fuels the world most thirsts for and is best configured to utilize: diesel and jet fuel.
Additives are non-hydrocarbon substances added or blended with a product to modify its properties, for example, to improve its combustion characteristics. Alcohols and ethers (MTBE, methyl tertiary-butyl ether) and chemical alloys such as tetraethyl lead are included here. However, ethanol is not included here, but under liquid biofuels.
NGLs are the liquid or liquefied hydrocarbons produced in the manufacture, purification and stabilisation of natural gas. These are those portions of natural gas which are recovered as liquids in separators, field facilities, or gas processing plants. NGLs include but are not limited to ethane, propane, butane, pentane, natural gasoline and condensate.
Other hydrocarbons includes emulsified oils (e.g. orimulsion), synthetic crude oil, mineral oils extracted from bituminous minerals such as oil shale, bituminous sand, etc. and liquids from coal liquefaction.
A refinery feedstock is processed oil destined for further processing (e.g. straight run fuel oil or vacuum gas oil) other than blending in the refining industry. It is transformed into one or more components and/or finished products. This definition covers those finished products imported for refinery intake and those returned from the petrochemical industry to the refining industry.
Why not turn natural gas into liquid products that are easier and less costly to transport? There are a handful of gas-to-liquids plants around the world that do just that. But the economics of mega-scale GTL projects work only at a handful of locations. What about smaller gas resources?
Crude oil comprises crude oil, natural gas liquids, refinery feedstocks, and additives as well as other hydrocarbons (including emulsified oils, synthetic crude oil, mineral oils extracted from bituminous minerals such as oil shale, bituminous sand, etc., and oils from coal liquefaction). Crude oil is a mineral oil consisting of a mixture of hydrocarbons of natural origin and associated impurities, such as sulphur. It exists in the liquid phase under normal surface temperatures and pressure and its physical characteristics (density, viscosity, etc.) are highly variable. It includes field or lease condensates (separator liquids) which are recovered from associated and non-associated gas where it is commingled with the commercial crude oil stream. For more information on a specific product, please see the following list: