Results with pyrolysis oils

Table /. Summary of results for Scots pine sapwood blocks treated with pyrolysis oil and attacked by the brown-rot fungus Coniophora puteana. 

From the above-mentioned results with the oil shale retorting products, the pertinent question of whether the inorganic arsenic and organoarsenic compounds were actually natural products that were formed in the fossilization process of oil shale formation or were pyrolysis products formed during retorting, needed to be answered. 

The aqueous-phase pyrolysis can also be assisted by catalysts and reactive gases. For instance, the PERC process [3, 33] produces a pyrolysis oil upon dissolving wood chips in a recycle pyrolysis oil, mixing the slurry with a water-Na2C03 solution and treating the resulting mixture at 370 °C and 275 bar under synthesis gas atmosphere. 

Prime movers on pyrolysis oil Results of test concerned with the combustion of pyrolysis oils in a boiler are reported. And finally, preliminary attempts of combustion experiments with a gas turbine will be described. 

The percentage in pyrolysis oil increased with temperature up to 400 °C, then leveled off at 200 s. The shorter pyrolysis gave a higher percentage at 450 C by around 5 %, An increase in temperature produced no significant increase in the arsenic content. Pyrolysis for 3600 s gave higher arsenic content in the pyrolysis oil at 350 °C. A shorter pyrolysis time resulted in a lower concentration in the oil. 

The metal-organic preservatives copper HDO and aluminum HDO are commonly used for timber used in landscape improvement. Therefore, sanq)les impregnated with these preservatives were also pyrolyzed at 500 °C. Aluminum could not be measured in the oil because the chamber had to be evacuated which would have contaminated the inner walls with pyrolysis liquids. Therefore, only the char was analyzed for A1 resulting in a recovery of 82.7 %. Hence, 17.3 % of the input aluminum is expected to remain in the oil. This is much more compared to Cu and Cr due to the lower melting and boiling point of Al. 

The results of chemical characterisation were not very consistent. It was discussed to prepare standard solutions with known amounts of compounds for quantitative analyses. A question was also raised if the functional groups in pyrolysis oil should be analysed analogously with petroleum residues instead of individual compounds, as by quantitative C-NMR. The amount of PAH (polyaromatic hydrocarbons) was extremely high for one pyrolysis oil, and it was discussed that more attention should be paid to the analysis of toxic compounds in the oils. The oil producer commented later that the high PAH may be due to contamination of other fuel and this will be checked. 

The main conclusions of the Round Robin were Karl-Fischer titration is recommended for analysing water in pyrolysis oils. Solids content as ethanol insolubles is accurate for white wood oils but a more powerful solvent, like a mixture of methanol and methylene chloride (1 1) is needed for extractive-rich oils. For the elemental analysis at least triplicates are recommended. Kinematic viscosity is an accurate method for pyrolysis oils. Stability index needs more clarification and testing,- Results of chemical characterisation were not very consistent. It may be necessary to prepare standard solutions with known aniounts of conqiounds for... 

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. 

Likewise, Orr et al.29,30 have explored the possible use of tyre pyrolysis oil as a solvent for coal liquefaction. The potential of this alternative was demonstrated by the fact that coal-TPO mixtures were transformed with higher conversion than when coal was reacted directly with ground waste rubber tyres. It is proposed that the polyaromatic compounds present in the TPO favour coal dissolution during liquefaction. Treatment of coal-TPO mixtures (50/50%) at 430 °C under 68 atm of cold-hydrogen pressure in the presence of a Mo catalyst led to a high coal conversion in just 10 min of reaction. From electron probe microanalysis of the coal particles after the reaction, the authors conclude that TPO favours the catalyst dispersion and its contact with coal, which results in enhanced coal conversion. 

Experiments with peanut shell pyrolysis vapor reforming duplicated the 5-cm bench-scale unit results with the aqueous fraction of wood pyrolysis oil. This is the first time whole pyrolysis vapors have been processed in the fluid bed reforming process. 

A schematic and photograph of the pilot-scale catalytic fluid bed reformer are shown in Figure 4. The 30-cm catalytic steam reforming reactor was successfully operated on peanut pyrolysis vapor at a feed rate of 7 kg/hour of vapors. The results are in agreement with those obtained from the 5-cm bench-scale reactor used for the reforming of the aqueous fraction of pyrolysis oil. Typical gas compositions at the outlet of the reformer are shown in Figure 5. These data show that the yield of hydrogen is approximately 90% of maximum. 

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