Re: Tar Sands Showdown in the Nebraska Sandhills
Briefly:
Originally posted by oddlots
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Briefly:
- Fresh water might be an irreplaceable resource, in that there is no obvious substitute for it, but it is most certainly not an non-renewable resource. Perhaps using it in the tar sands is the best possible use for it compared to trying to grow crops on marginal land in arid regions, or watering golf courses?
- Natural gas is not a direct substitute for crude oil. If it was it would not sell at such a significant discount on an energy content basis [$ per btu] to crude oil.
- Condensate and natural gas liquids [NGLs] are already included in the global statistics for "crude oil" production and consumption. More than 10 million barrels per day of the roughly 85-89 million barrels per day of reported global crude oil consumption is actually not crude oil, but condensate and NGL liquids.
- Condensate and NGLs are the easiest components of natural gas to substitute for crude oil in such applications as transport fuel, but not without some challenges. At atmospheric pressure the propane component of NGL has to kept at -44 deg F to keep it in a liquid state. The alternative is to hold it in a pressure vessel [fuel tank]...at 80 deg F that tank will be under 130 psi pressure; at 110 deg F it has to be capable of holding almost 200 psi.
- The remainder of the natural gas stream, which is the majority of it, is very difficult to substitute for crude oil products, particularly transportation. Liquified natural gas [LNG] has to be cooled to about minus 260 deg F. This uses a lot of energy.
- Some energy companies, especially Royal Dutch Shell and South African based SASOIL, have been working for a long time to commercialize natural gas to liquids [GTL] conversion technologies. Both companies have GTL plants in the Gulf State of Qatar. Most of these efforts seem to be some variation of the Fisher-Tropsch process used to create a synthetic liquid fuel from gas. This is the same process that was used by Germany in WWII to convert coal gas into fuel for the military, and by South Africa during the apartheid sanctions to try to become more self sufficient in the manufacture of transport fuels. The dirty little secret is that a huge amount of the inlet energy content, much more than required to make LNG, is consumed in the manufacturing process [roughly one-third of the energy inlet is used up in the process]. Perhaps in time this will improve. Certainly that is one of the goals of the proponents of GTL. But at this time that fuel is a long, long way from becoming any material portion of the transport fuel equation.
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