Fractionation of pyrolysis oils

Fractionation of Pyrolysis Oils. Pyrolysis oil obtained from the vortex reactor was fractionated according to the scheme shown in Figure 3. Whole oil (1 kg) was dissolved in ethyl acetate (EA) on a 1 1 (w/w) basis. The oil was then vacuum filtered through filter paper to remove fine char. Upon standing, the EA/pyrolysis oil separated into two phases-an organic rich, EA-soluble phase and an EA-insoluble phase. Most of the water formed during pyrolysis is contained in the EA-insoluble phase. The EA-soluble portion of the oil was washed with water (2 x 75 mL) to remove the remaining water-soluble derived products. 

Of the various fractions of pyrolysis oil, only the P/N fraction gave a positive gel test under these conditions. In preliminary gel testing of the P/N extract, arbitrarily 1 g of paraformaldehyde was added to 4 g of the extract. The pH of... 

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. 

The identification and extraction of valuable chemicals from wood-derived oils is a very important goal for the biomass thermochemical conversion industry (lz2). Pyrolysis oils have been extensively studied and extensive number of compounds have been identified (3-4). However to our knowledge there are only two general methods which have been reported for the fractionation of pyrolysis oils... 

SEC in combination with multidimensional liquid chromatography (LC-LC) may be used to carry out polymer/additive analysis. In this approach, the sample is dissolved before injection into the SEC system for prefractionation of the polymer fractions. High-MW components are separated from the additives. The additive fraction is collected, concentrated by evaporation, and injected to a multidimensional RPLC system consisting of two columns of different selectivity. The first column is used for sample prefractionation and cleanup, after which the additive fraction is transferred to the analytical column for the final separation. The total method (SEC, LC-LC) has been used for the analysis of the main phenolic compounds in complex pyrolysis oils with minimal sample preparation [974]. The identification is reliable because three analytical steps (SEC, RPLC and RPLC) with different selectivities are employed. The complexity of pyrolysis oils makes their analysis a demanding task, and careful sample preparation is typically required. 

Pyrolysis oil (bio-oil) is produced in fast and flash pyrolysis processes and can be used for indirect co-firing for power production in conventional power plants and potentially as a high energy density intermediate for the final production of chemicals and/or transportation fuels. Gas chromatographic analysis of the liqtrid fraction of pyrolysis products from beech wood is given in Table 3.6 (Demirbas, 2007). Biocmde resrrlts from severe hydrothermal upgrading (HTU) of relatively wet biomass and potentially can be used for the production of materials, chemicals,... 

Scholze B. Meier D. (2000) Characterization of the water-insoluble fraction from pyrolysis oil (pyrolytic lignin), Part I. Py- GC/MS, FTIR, and functional groups, J. Anal. Appl. Pyrolysis, in press. 

Details on the preparation of pyrolysis oils at SERI in the entrained-flow, fast ablative pyrolysis reactor can be found in a report by Diebold and Scahill (2). The oils in Figure 1 were obtained from two runs, 40 (c and d) and 41 (a and b), the oils being collected from a packed scrubber (a and c) and a cyclone scrubber (b and d). The oil obtained from the packed scrubber in run 41 was subjected to sequential elution by solvents chromatography (SESC) according to the method of Davis et al (7). The HPSEC of fractions 1 through 6 appear in Figure 3. Fraction 1 was eluted with 15% toluene in hexane (yield 0.4%), Fraction 2 was eluted with chloroform (yield 1.5%), Fraction 3 was eluted with 7.5% ether in chloroform (yield 7.5%), Fraction 4 was eluted with 5% ethanol in ether (yield 19.5%), Fraction 5 was eluted with methanol (yield 38.1%), and Fraction 6 was eluted with 4% ethanol in THF (yield 3.1%). The oils displayed in Figures 4 and 5 were produced from run 66. 

Pyrolysis has a long history in the upgrading of biomass. The dry distillation of hardwood was applied in the early 1990s to produce organic intermediates (methanol and acetic acid), charcoal and fuel gas [3]. Today s processes can be tuned to form char, oil and/or gas, all depending on the temperature and reaction time, from 300 °C and hours, to 400-500 °C and seconds-minutes, to >700 °C and a fraction of a second [3, 19, 23, 24], The process is typically carried out under inert atmosphere. We illustrate the basic chemistry of pyrolysis by focusing on the conversion of the carbohydrate components (Fig. 2.4). The reaction of the lignin will not be covered here but should obviously be considered in a real process. Interested readers could consult the literature, e.g., [25]. Pyrolysis is discussed in more details elsewhere in this book [26],... 

CO = 25 vol.%, C02 = 12 vol.%) not containing any hydrocarbons and a low tar (200 mg Nm 3) content at 800 °C and S/C (steam over carbon ratio) = 1.5. Problems associated with pyrolysis oil gasification are similar to those of biomass gasification. Gasification of the tar fraction and conversion of methane formed are important challenges. Both require highly active and stable steam/autothermal reforming catalysts. 

Gayubo, A.G., Aguayo, A.T., Atutxa, A., Prieto, R., Bilbao, J., Deactivation of a HZSM-5 zeolite catalyst in the transformation of the aqueous fraction of biomass pyrolysis oil into hydrocarbons, Energy Fuels, 2004, 18, 1640. 

M. Mann, E. Chorlet, in Hydrogen production via catalytic steam reforming of fast pyrolysis oil fractions. Proceedings of the 3ri Biomass Conference of the Americas, Pergamon, Oxford, 1997, p. 845. 

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