Pyrolysis Oil Biorefinery.

In biorefineries several conversion processes for biomasses may be applied to obtain maximum value from the feed materials. One viable option is the liquefaction of lignocellulosic feedstocks or residues by fast pyrolysis. The conversion technology requires rapid heating of the biomass particles along with rapid cooling of the hot vapors and aerosols. The main product, bio-oil, is obtained in yields of up to 75 wt% on a dry feed basis, together with by-product char and gas which are used within the process to provide the process heat requirements; there are no waste streams other than flue gas and ash. Bio-oils from fast pyrolysis have a great potential to be used as renewable fuel and/or a source for chemical feedstocks. Existing technical reactor designs are presented together with actual examples. Bio-oil characterization and various options for bio-oil upgrading are discussed based on the potential end-use. Existing and potential utilization alternatives for bio-oils are presented with respect to their use for heat and power generation as well as chemical and material use.

Quantitative Insights into the Fast Pyrolysis of Extracted Cellulose, Hemicelluloses, and Lignin.

The transformation of lignocellulosic biomass into bio-based commodity chemicals is technically possible. Among thermochemical processes, fast pyrolysis, a relatively mature technology that has now reached a commercial level, produces a high yield of an organic-rich liquid stream. Despite recent efforts to elucidate the degradation paths of biomass during pyrolysis, the selectivity and recovery rates of bio-compounds remain low. In an attempt to clarify the general degradation scheme of biomass fast pyrolysis and provide a quantitative insight, the use of fast pyrolysis microreactors is combined with spectroscopic techniques (i.e., mass spectrometry and NMR spectroscopy) and mixtures of unlabeled and 13 C-enriched materials. The first stage of the work aimed to select the type of reactor to use to ensure control of the pyrolysis regime. A comparison of the chemical fragmentation patterns of "primary" fast pyrolysis volatiles detected by using GC-MS between two small-scale microreactors showed the inevitable occurrence of secondary reactions. In the second stage, liquid fractions that are also made of primary fast pyrolysis condensates were analyzed by using quantitative liquid-state 13 C NMR spectroscopy to provide a quantitative distribution of functional groups. The compilation of these results into a map that displays the distribution of functional groups according to the individual and main constituents of biomass (i.e., hemicelluloses, cellulose and lignin) confirmed the origin of individual chemicals within the fast pyrolysis liquids.

Characterisation of spruce, salix, miscanthus and wheat straw for pyrolysis applications.

This research details the characterisation of four Irish-grown lignocellulosic biomasses for pyrolysis by biomass composition analysis, TGA, and Py-GC/MS-FID. Ash content (mf) increased in the order spruce (0.26 wt.%) < salix (1.16 wt.%) < miscanthus (3.43 wt.%) < wheat straw (3.76 wt.%). Analysis of hydrolysis-derived sugar monomers showed that xylose concentrations (4.69­26.76 wt.%) ranged significantly compared to glucose concentrations (40.98­49.82 wt.%). Higher hemicellulose and ash contents probably increased non-volatile matter, and decreased the temperature of maximum degradation by TGA as well as yields of GC-detectable compounds by Py-GC/MS-FID. Differences in composition and degradation were reflected in the pyrolysate composition by lower quantities of sugars (principally levoglucosan), pyrans, and furans for salix, miscanthus, and wheat straw compared to spruce, and increased concentrations of cyclopentenones and acids.

Chromatographic approaches for determination of low-molecular mass aldehydes in bio-oil.

HPLC-UV and GC/MS determination of aldehydes in bio-oil were evaluated. HPLC-UV preceded by derivatization with 2,4-dinitrophenylhydrazine allows separation and detection of bio-oil aldehydes, but the derivatization affected the bio-oil stability reducing their quantitative applicability. GC/MS determination of aldehydes was reached by derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. Two approaches for this reaction were evaluated. The first: "in solution derivatization and head space extraction" and the second: "on fiber derivatization SPME", the latter through an automatic procedure. Both sample treatments allows the quantification of most important aliphatic aldehydes in bio-oil, being the SPME approach more efficient. The aldehyde concentrations in bio-oil were ~2% formaldehyde, ~!0.1% acetaldehyde and ~0.05% propionaldehyde.

Composition and analysis of liquid smoke flavouring primary products.

Smoke flavourings are produced on a large scale and have been applied to a variety of food products for more than 30 years. The use of them has many advantages compared to traditional smoking techniques. Among others, the amount of (known) toxic compounds deriving from combustion processes can be more easily controlled in smoke flavourings. In order to ensure safe products, a new European Regulation requests data on the composition and lays down, in particular, the maximum permitted concentrations for selected polycyclic aromatic hydrocarbons (PAHs). This review compiles results published on the chemical composition of liquid smoke flavouring primary products, partly in relation to production process parameters, and the analytical methods involved. The methods cover chromatographic techniques for analysis of specific compounds including extraction methods and clean-up procedures. Analysis of sensorial and bulk parameters such as acidity and total phenolic compounds are described as well as they are used as standard methods for analysis of liquid smoke flavourings. A special section is devoted to discussing the analysis of PAHs.