Pyrolysis organic compound decomposition

The ISV process uses electricity to heat and melt soil and other earthen materials contaminated with organic, inorganic, and radioactive compounds. Organic compounds undergo pyrolysis (thermal decomposition in the absence of oxygen). The pyrolyzed compounds then migrate to the surface zone, where they are collected and oxidized in a collection hood. Inorganic and radioactive components are incorporated as oxides into a leach-resistant vitrified product. 

Pyrolysis units are expected to have minimal air pollution impacts because most of the pyro-gas generated in the pyrolysis process is burned as fuel in the process. During burning, the organic compounds are destroyed. Assuming complete combustion, the decomposition products are water, carbon dioxide, carbon monoxide, sulfur dioxide and nitrogen oxides ... 

Biacetyl has often been used for sensitizing the pyrolysis of organic compounds" . Radicals, resulting from the thermal decomposition of biacetyl, initiate the chain decomposition of such substances. However, NO causes no inhibition of notable significance in such systems . Nevertheless, this cannot be considered as an evidence against the occurrence of chains, since the sensitized decompositions are definitely inhibited by, for instance, propene . 

There is no certain of which one is the dominant. It is known that carbonate decomposition and sodium release start about 615 C. These carbonates are from both, the chemical pulping of lignocellulosic materials and from the conversion of the sodium organic compounds contained in the black liquor during pyrolysis under 675 C. 

The decomposition of pure phase carbonate minerals has been extensively studied and reviewed (17). The influence of these minerals on oil shale pyrolysis kinetics has not been extensively studied, but the studies of Jukkola et al. (18) and Campbell (15) are notable. The results of both these studies indicate that the major calcite decomposition step is through reaction with silicate minerals in shale to produce Ca- and Ca-, Mg-silicates. The observed enhancement in pyrolysis yield after carbonate removal may be indicative of the catalytic role of silicate minerals in paraffinic and aromatic compound decompositions. In effect, an apparent preference for calcite-silicate interactions in raw shale limits silicate-catalyzed organic reactions which would presumably result in enhanced oil yields. It should be noted, however, that the silicate/carbonate ratio is increasing with net pyrolysis yield for the raw shales, Table I. This may reflect excess silicates becoming free to catalyze organic decomposition. 

Studies on the pyrolysis of starch have attracted attention since 1913. In a historically first report, Bantlin determined the following yields of products from rice starch decomposed at temperatures raised within 7 h from 100 to 500° 12% of coke, 30% of water, 3% of tar, 5% of acetic acid, 6% of various aldehydes, 1.1% of ketones, 13% of carbon dioxide, 8% of carbon monoxide, and some hydrogen and ethylene. Sandomini was the first to study the influence of metal oxides (of Al, Cr, and Zn). He did not observe any appreciable effects of these additives on the decomposition at 270 to 300 of several organic compounds, among them starch and cellulose. 

Most promising is flash pyrolysis in which fuel particles are heated very rapidly (more than 1,000 °Cs ) and remain in the hot zone for a very short time (in general less than 1 s). After this very short time period, the liquid compounds produced from the solid biomass by decomposing the organic compounds (z.e. lignin, celluloses) have to be removed and cooled rapidly to avoid further decomposition into gases. To date, flash pyrolysis reactors have reaehed laboratory stage development level and the first pilot plants are available. 

The synthesis of multicomponent oxide materials via polymerizable complex method suffers from the drawbacks common for all techniques that utilize large amount of organic compounds. The pyrolysis ofthe polymer gel yields metal oxides and carbonates. As we have already discussed, the decomposition of an alkaline-earth carbonate slows down the sohd state reaction and requires high temperatures for synthesis despite the good homogeneity and the small size ofthe particles. 

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