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| "if it wasn't for the invention of X we wouldn't have Y" |
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| magic:
Wikipedia is usually wrong about everything and always misleading. Coal is mostly heavy and complex hydrocarbons, and pure carbon is graphite or sometimes diamond. Coal can be used to synthesize simpler hydrocarbons, such as gasoline, without putting all the energy into it that will later be extracted by burning. |
| Kleinstein:
For the chemistry oil and coal can be replaced with biological sources of carbon / hydrocarbons. This tends to be more expensive and may need some additional effort, but it is possible. The main problem getting away without oil and coal is the higher price in the cases were they are used to burn as energy source. With limited supplies we will have to reduce the consumption and a high price is thus natural and good. |
| jpanhalt:
--- Quote from: magic on August 22, 2022, 05:59:33 am ---Coal is mostly heavy and complex hydrocarbons, and pure carbon is graphite or sometimes diamond. Coal can be used to synthesize simpler hydrocarbons, such as gasoline, without putting all the energy into it that will later be extracted by burning. --- End quote --- I disagree. Can you provide a citation for converting coal to gasoline without adding any energy, chemical or otherwise. There are different types of coal. Some are more carbon rich than others. https://education.nationalgeographic.org/resource/coal Moreover, given coal's low ratio of hydrogen to carbon, one must reduce it to form hydrocarbon fuels. Source: https://www.britannica.com/science/coal-fossil-fuel --- Quote ---In general, coal can be considered a hydrogen-deficient hydrocarbon with a hydrogen-to-carbon ratio near 0.8, as compared with a liquid hydrocarbons ratio near 2 (for propane, ethane, butane, and other forms of natural gas) and a gaseous hydrocarbons ratio near 4 (for gasoline). For this reason, any process used to convert coal to alternative fuels must add hydrogen (either directly or in the form of water). --- End quote --- As for biodiesel and related, the most common method I have seen uses methanolysis of organic fats to give methyl esters of long-chain fatty acids. They are not hydrocarbons and have slightly less energy due to the RCOOR' group, but they are still mostly hydrocarbon and can often be substituted for hydrocarbon fuel. |
| pcprogrammer:
Just a thought, no idea if it is possible, but what if we extract CO2 from the atmosphere and recombine it with what ever is needed to make some sort of synthetic gasoline and keep running internal combustion engines on it and call it CO2 neutral. This instead of massively producing batteries for electric vehicles. Does not solve the excessive amount of CO2 there is now, but just switching to "renewable" energy does not solve this either. Only active extraction of CO2 and safely storing it could do it in a short time frame. Still leaves a lot of other problems with other forms of pollution, but something to think about. |
| magic:
--- Quote from: jpanhalt on August 22, 2022, 07:15:22 am ---I disagree. --- End quote --- I don't think you do, the point was simply that coal is far from being pure carbon, 10:8 C:H proportion per the source you found. --- Quote from: jpanhalt on August 22, 2022, 07:15:22 am ---Can you provide a citation for converting coal to gasoline without adding any energy, chemical or otherwise. --- End quote --- I suppose a whole spectrum of tradeoff is available between adding hydrogen or removing carbon. I don't know those processes. I'm pretty sure than in an act of desperation you could simply burn a fraction of the coal to obtain energy to upgrade the rest, resulting in a "no energy input" process with appropriately lower yield, but arguably that's an exercise in accounting rather than chemical engineering. |
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