Talk:Molten salt oxidation
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Issues
[edit]There are very subtle issues with molten salt oxidation, and it is not necessarily the proper solution for every scenario, without carefully weighing the details. Though it can increase the reaction rate by orders of magnitude for things such as wood gasification, where a carbonate/sulfate/sulfite melt could function as a fast oxygen carrier to solid/liquid reaction sites, at least in the case of rubber scraps, the high sulfur content becoming available as SO2/sulfuric acid from difficult regular combustion could generate a useful byproduct, if in sufficient quantity, as opposed to molten salt generated sodium sulfate, whose use is much less valuable, representing a lower energy point. For a low quantity, noneconomically recoverable amount of sulfur in the feed, molten salt is proper, but for high quantity it may be not. Eventually the whole melt may turn into sodium sulfate, leaving no sulfur absorbing capacity, and venting all sulfur as SO2 anyway. There is also an issue of maintaining oxidation potential in the melt. Should the melt turn into a heavily reducing environment, such as it is in localized zones of high carbon/organic waste/tire content, the reaction Na2SO4 + CO gas --> Na2CO3 + S(gas) may be possible, or just simply elemental S (sulfur) vaporizing from the tire because there is not enough oxygen available for the oxidation reaction. Then the path the S gas takes through the melt, and contact times/redox environments it encounters decides whether the final flue gases are S free or not. So just because the overall reaction rates are increased due to a melt attack on a solid surface by super-increased localized oxygen compound concentration, and fast dissolution/carry away of reaction products, one may still need a large and long residence time molten salt or some other phase scrubber setup for proper operation. The rate of heat flow vs. rate of oxygen is a critical parameter, and the rate of heat loss vs. oxygen takeup at the atmospheric contact is another one, which can be helped by the use of a recuperator. Sillybilly (talk) 22:49, 25 October 2009 (UTC)
Include predecessor
[edit]Last century garbage was often burned in incinerators rather than trucked to a "sanitary landfill". The usual practice at the time was addition of lime, Calcium Carbonate or Calcium Oxide, to in similar fashion to your molten salt destroy alkali sensitive substances i.e. removes pollutants. Otherwise, Dioxin is a product of ANY high temp organic oxidation with chloride present. Some cities incinerated in their coal powerplants, organic waste waste is part of alkaline coal ash. The alkaline coal ash acting like a Sodium Carbonate melt. Actual EPA study on using diesel diluted hazwaste in concrete manufacuring where the Chlorine from PCBs gets captured by the Calcium in the cement process. FYI China makes concrete using coal and not fuel oil, the coal ash actually strengthens the concrete. Important? Billg infographic that China from 2000-2010 poured 3.5x concrete the US poured from 1900-2000. TaylorLeem (talk) 21:38, 24 August 2020 (UTC)