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Science Forum

  1. 21 Apr '12 21:37
    Is this cost effective?

    http://www.greencar.com/articles/5-things-need-fischer-tropsch-process.php
  2. 22 Apr '12 09:02
    Originally posted by Metal Brain
    Is this cost effective?

    http://www.greencar.com/articles/5-things-need-fischer-tropsch-process.php
    I have no idea of the cost effectiveness but the bit that interests me is the latter part of:

    Many Raw Materials can be Used
    Some of the more promising applications for the F-T process include coal-to-liquid (CTL), gas-to-liquid (GTL), and bio-to-liquid (BTL) technologies. The latter would mean a less carbon-intensive alternative that could not only use agricultural feedstocks but also waste biomass materials.


    I wonder if anyone knows if that “biomass materials” can realistically include such things as sewage and waste food and waste straw? Could all that be economically converted to biofuel using this process? If so, I think that would be great.
  3. 22 Apr '12 12:33
    Originally posted by humy
    I have no idea of the cost effectiveness but the bit that interests me is the latter part of:

    [quote] Many Raw Materials can be Used
    Some of the more promising applications for the F-T process include coal-to-liquid (CTL), gas-to-liquid (GTL), and bio-to-liquid (BTL) technologies. The latter would mean a less carbon-intensive alternative that could not only ...[text shortened]... hat be economically converted to biofuel using this process? If so, I think that would be great.
    Biofuels are usually produced using crops (often corn or sugarbeet), as this is the most efficient way of doing it.
  4. 22 Apr '12 14:13
    Originally posted by KazetNagorra
    Biofuels are usually produced using crops (often corn or sugarbeet), as this is the most efficient way of doing it.
    Actually it is well known that it is highly inefficient. So much so that it takes more fossil fuels to grow the crops than is being replaced by the biofuels.
  5. 22 Apr '12 14:17
    Originally posted by humy
    I wonder if anyone knows if that “biomass materials” can realistically include such things as sewage and waste food and waste straw? Could all that be economically converted to biofuel using this process? If so, I think that would be great.
    Biogas can be produced from sewage (human) as well as animal manure. It is used quite a lot in some parts of the world, but needs to be used a lot more.
  6. 22 Apr '12 14:20
    Originally posted by Metal Brain
    Is this cost effective?

    http://www.greencar.com/articles/5-things-need-fischer-tropsch-process.php
    Here in SA a significant proportion of our fuel is produced from coal via this process. As far as I know its not particularly 'green' when coal is used.
  7. Standard member sonhouse
    Fast and Curious
    22 Apr '12 17:32
    Originally posted by twhitehead
    Actually it is well known that it is highly inefficient. So much so that it takes more fossil fuels to grow the crops than is being replaced by the biofuels.
    Here is some breakthrough technology just coming on the market due to over ten years work of a genius lady:

    http://phys.org/news/2012-04-waste-to-energy-technology-lab-marketplace.html
  8. 23 Apr '12 16:28
    Originally posted by twhitehead
    Here in SA a significant proportion of our fuel is produced from coal via this process. As far as I know its not particularly 'green' when coal is used.
    I know it is not really green. That just happens to be the name of the link I thought was informative.

    I am interested in the process of converting natural gas into liquid fuel since natural gas is about half the price as gasoline in the USA. That would eliminate the need to set up a separate fuel at fueling stations for a natural gas powered car. This would eliminate the need for a compressed natural gas car (like the Honda Civic) that is more costly.

    The competition would be good for the consumer.
  9. 23 Apr '12 21:19
    Originally posted by twhitehead
    Actually it is well known that it is highly inefficient. So much so that it takes more fossil fuels to grow the crops than is being replaced by the biofuels.
    It takes fossil fuels to grow crops? I think you're a bit confused. Any fossil fuels that are used in the production of biofuels can in principle be replaced by renewable alternatives.
  10. 24 Apr '12 01:55
    Originally posted by KazetNagorra
    It takes fossil fuels to grow crops? I think you're a bit confused. Any fossil fuels that are used in the production of biofuels can in principle be replaced by renewable alternatives.
    You heard of tractors, combine-harvesters, crop spraying aircraft, fertilisers ect

    All use fuel to make transport and use.

    Also the biofuels need processing to turn into fuel which takes energy (more fuel)
    And then you have to factor in the trucking of all this fuel around.

    Crop based biofules are renowned for using about as much fossil fuel to make as they
    replace.
    Plus of course you are taking up land area that could be used for food production or left
    wild.
  11. 24 Apr '12 06:27 / 1 edit
    Originally posted by KazetNagorra
    It takes fossil fuels to grow crops? I think you're a bit confused. Any fossil fuels that are used in the production of biofuels can in principle be replaced by renewable alternatives.
    Principle and what actually happens are two very different things. And if they used the produced bio-fuels for the production process there would be no output! You would be essentially paying farmers to waste all that water and land producing nothing! Oh, wait a moment, thats what the US already does.
  12. 24 Apr '12 06:34
    Originally posted by Metal Brain
    I am interested in the process of converting natural gas into liquid fuel since natural gas is about half the price as gasoline in the USA.
    After some research I see that in South Africa we use Natural Gas as well as coal. I have not been able to find any stats on the matter but I remember reading somewhere that about 30% of our fuel comes from these sources.

    You could start here if you want to learn more:
    http://en.wikipedia.org/wiki/Sasol
  13. 24 Apr '12 06:40 / 1 edit
    Originally posted by sonhouse
    Here is some breakthrough technology just coming on the market due to over ten years work of a genius lady:

    http://phys.org/news/2012-04-waste-to-energy-technology-lab-marketplace.html
    It has some improvements over previous digesters, but digesters are hardly new technology. According to this site:
    http://www.biogassa.co.za/
    India has more than 4.5 million digesters.

    Here is a site that seems to think they are not a good idea:
    http://www.energyjustice.net/digesters