The main aim of this study is to provide the experimental research of the combustion characteristics for the different types of the biomass pellets during their thermo chemical conversion with estimation the correlations between the main characteristics of pelletized plant biomass and combustion characteristics.The experiments include first, the preparation of the pelletized biomass samples of different origin with certain elemental composition, heating values, moisture content, bulk and energetic density, and second, kinetic study of the combustion characteristics with local measurements of the temperature and composition of the flame reaction zone and heat production rates at different stages of the thermo chemical conversion of pelletized biomass and different air supply rates into the combustor to obtain optimal combustion conditions of plant biomass.Correlations between the main characteristics of pelletized samples and combustion/emission characteristics of pelletized biomass fuel have been derived and analyzed.

The barks of deciduous trees spread over a wide area of Northern Europe, were sequentially extracted using solvents of increasing polarity. The highest yields of hydrophilic extractives were found for ash tree and goat willow (23.6% and 23.8%, respectively). The highest total contents of polyphenols were found for black alder and goat willow bark (0.18 GAE.g(-1) and 0.12 GAE.g(-1), respectively). Hydrophilic extract from the both grey and black alder barks contained high amount (up to 7 % on bark dry mass) of condensed tannins (CT) or oligomeric proanthocyanidins (OPC). In tests with free radicals (ABTS(center dot+), DPPH center dot), the high radical scavenging capacities of the hydrophilic extracts enriched with OPC were demonstrated. The antioxidant efficiency of the hydrophilic extracts and purified OPC from alder barks was tested by their influence on thermo-oxidative destruction of model polyurethane (PU) films. The hydrophilic extracts enriched with tannins have good potential as a technical antioxidant for polyurethanes, with the most prominent activity for the hydrophilic extract from black alder and goat willow bark.

Wheat straw lignin was pretreated by organic solvents of different polarity: ethylacetate, ethylmethylketone and ethylmethylketone/water mixture, using sequential extraction technique. The total yield of fractions was ∼ 40% (w/w). In comparison with non- treated lignin the solvent soluble fractions have lower molecular weights, lower polydispersity and average functionality indices. The low viscosity lignopolyols with lignin substituent content up to 40%, suitable for rigid polyurethane foams obtaining were produced by the oxypropylation of isolated fractions. The non-soluble in organic solvents lignin residue represent a purified natural aromatic amorphous cross-linked polymer. Therefore besides oxypropylation its application as filler of thermostable polymers with enhanced flammable resistance could be beneficial biorefinery approach.

Lignin preparations, introduced into soil jointly with buckwheat Fagopyrum esculentum Moench, variety 'Aiva' (cultivated throughout Latvia) seeds during the sowing in quantities of 20 kg ha-1 and 40 kg ha-1, exerted a favourable effect on the ned in alcohol extracts from the biomass of different morphological parts of buckwheat, were represented mainly by rutin. The content of rutin in the ethanol extracts from the biomass of flowers with bract reached the maximum values in the phase of accomplishing blooming - beginning of fruit formation to be 2.74% in terms of dry mass (exceeding the rutin content development of plants and the synthesis of flavonoids in flowers with bract. Flavonoids, determin the control by 65%) in the variant with 40 kg ha-1 of Lignosilicon. Lignin preparations favoured the increase in the radical scavenging capacity of the alcohol extracts of the biomass of flowers with bract of buckwheat, as well as grain and hulls. The increment of the buckwheat grain crop, in comparison with the control on the background of 40 kg ha-1 of lignin, was 12%, and that on the background of 20 kg ha-1 and 40 kg/ha of Lignosilicon 10% and 15%, respectively.

In present work the BIOLIGNIN (TM) obtained in the result of wheat straw organosolv processing in CIMV pilot plant (France) was investigated as a component of rigid polyurethanes (PUR) foam systems. Different separate approaches of lignin introduction into PUR foam system were studied: as filler without chemical preprocessing and as liquid lignopolyol obtained by lignin oxypropylation in alkali conditions. The incorporation of increasing amount of lignin as filler into reference PUR foam systems on the basis of mixture of commercial polyethers Lupranol 3300 and Lupranol 3422 steadily decreased the compression characteristics of foams, their dimensional stability and hydrophobicity. The complete substitution of Lupranol 3300 by lignopolyol increases its cell structure uniformity and dimensional stability and does not reduce the physical-mechanical properties of foam. In both cases the incorporation of lignin into PUR foam leads to the decreasing of maximum values of thermodegradation rates. The lignin filler can be introduced into lignopolyol based PUR foam in higher quantity than in the reference Lupranol based PUR without reduction of compression characteristics of material. In this work the optimal lignin content in the end product - PUR foam as both polyol and filler is 16%.

Non-purified lignins resulting from ethanol-based organosolv fractionation of wheat straw were characterized for the presence of impurities (carbohydrates and ash), functional groups (hydroxyl, carboxyl and methoxyl), phenyl-propanoid structural moieties, molar mass distribution and thermal behavior. In accordance with its herbaceous nature, the syringyl/guaiacyl-ratio of the wheat straw lignins was substantially lower than of Alcell lignin. In addition, the content of p-hydroxyphenyl and carboxyl groups is substantially higher for the wheat straw lignins. The non-purified organosolv lignins had a high purity with 0.4–5.2% carbohydrate impurities, both originating from lignin to carbohydrate complexes and residual organosolv liquor. The use of H2SO4 in the organosolv process improved the lignin yield, but at low acid doses increased the carbohydrate impurities. For applications where a low amount of carbohydrates is important, lignin from a high-temperature autocatalytic organosolv process was found to be preferred. The highest content of total hydroxyl groups was determined when lignins were produced using 30 mM H2SO4 as catalyst or 50% w/w aqueous ethanol as solvent for the organosolv process. Aliphatic hydroxyl groups, the most predominant type of hydroxyl groups present originating for a substantial part from residual carbohydrates, were found to decrease with reaction time and ethanol proportion of the organosolv solvent. The correlations between organosolv process conditions and lignin characteristics determined can facilitate the use of organosolv lignins in value-added applications such as in polymers and resins and as a feedstock for bio-based aromatics.

Changes in structural characteristics of humic and fulvic acids (HA and FA) were studied during the composting of wastewater of slaughterhouse with lignocelluloses wastes, such as sawdust and grass. Humic substances were extracted by NaOH, purified and dialysed. Freeze-dried humic substances were characterised by UV and EPR (electron paramagnetic resonance) spectroscopy and size exclusion chromatography (SEC). UV spectra were described by absorbance ratios: E 2/E 4, E 2/E 3, E 4/E 6 and E 2/E 6. The results indicated the difference between chromophore systems of compost FA and HA. The average molecular weight of HA decreased, while the molecular weight of FA did not change significantly during composting. There was a good correlation between E 4/E 6 and compost HA molecular weight. The ratios E 2/E 4 and E 3/E 4 for both FA and HA showed high correlation with main EPR parameters such as spin concentration, extent of conjugation and line width.

Abstract To effectively produce clean heat energy from biomass, microwave (mw) pre-processing of its different types - pelletized wood (spruce), herbaceous biomass (reed canary grass) and their mixture (50:50) - was carried out at the 2.45 GHz frequency with different durations of biomass exposure to high-frequency oscillations. To estimate the mw pre-processing effect on the structure, composition and fuel characteristics of biomass, its thermogravimetric (TG), infrared spectroscopy (FTIR) measurements and elemental analysis were made. The pre-processing is shown to enhance the release of moisture and low-calorific volatiles and the partial destruction of biomass constituents (hemicelluloses, cellulose), promoting variations in the elemental composition and heating values of biomass. The field-enhanced variations of biomass characteristics and their influence on its gasification and combustion were studied using an integrated system of a biomass gasifier and a combustor with swirl-enhanced stabilization of the flame reaction zone. The results show that the mw pre-processing of biomass pellets provides a faster weight loss at the gasification, and, therefore, faster ignition and combustion of the activated pellets along with increased output of heat energy at their burnout

The study is aimed at cleaner and more efficient heat energy production through investigation and analysis of the thermal decomposition of lignocellulosic biomass pellets with different elemental composition, the heating values and contents of hemicellulose, cellulose and lignin. The estimation is provided for the influence of biomass composition on the combustion characteristics for softwood, wheat straw and wheat straw lignin pellets. The kinetics of thermal decomposition was studied experimentally, using a pilot device for two-stage processes of thermochemical conversion including gasification and combustion of biomass pellets under varying conditions. The experimental study includes time-dependent measurements of the biomass pellet weight loss during gasification and the correlating variations of the flame temperature, heat production rates, combustion efficiency and composition of the products at different stages of thermochemical conversion. Estimation is also given for the influence of the biomass composition on the combustion characteristics and heat energy production.

In the present work lignin, extracted from wheat straw in organic acid media (product of a novel biomass refinery technology developed at CIMV, France), was subjected to oxidative modification. The regimes of oxidative modification catalyzed by [PMo12O40] 3- (POM) increasing content of lignin hydroxyl groups, in particular carboxyl groups (more than twice) and not accompanied by degradation of the lignin polymeric structure have been developed earlier (EcoBalt 2012). Such oxidizing of lignin before its oxypropylation can be considered as a favorable pretreatment stage of lignin because increasing the amount of reactive sites able to copolymerization with propylene oxide. The modification was performed using as reoxidant for POM (1) oxygen of air or (2) H2O2 under moderate conditions: pressure of 1 bar and temperatures of 90 0 C (O2 reoxidant) and 50 0 C (H2O2 reoxidant). The effect of the oxidative treatment on the lignin functionality and structure was evaluated using Py-GC/MS, solid state 13 C NMR and chemical analysis. It was established that use of the H2O2 reoxidant in the process of lignin oxidation was more promising in comparison with the O2, because it allowed to increase the content of targeted hydroxyl groups, at significantly lower demand of POM (approximately by 25 times) and temperature of the process (50 о С against 90 о С). The oxypropylation of the parent and oxidized lignins with propylene oxide (PO) was studied in high pressure Parr reactor using KOH as a catalyst. It was shown that oxypropylation of lignin pre-oxidized in the system POM/H2O2 proceeded in the similar manner as the parent lignin but the rate of the process was some lower due to the presence of higher amount of -COOH groups with lower nucleofility. Oxypropylation of lignin oxidized in the system POM/O2 proceeded dramatically slower and was characterized by high residual pressure of non-reacted PO, and high amount of solids fraction (~30%) in reaction products. This can be explained by the neutralization of alkali catalyst by [PMo12O40] 3- presented in the lignin oxidized by POM/O2 as an admixture. Therefore, the method of lignin pre-oxidation in the system POM/H2O2 was chosen in order to obtain polyols for polyurethanes (PU) production. The composition of polyols obtained from the parent and oxidized lignins, their functional characteristics and reactivity with isocyanate were studied. Both the parent lignin and oxidized lignin based polyols were applied in composition of cross linked PU elastomers. The tensile and thermal properties of PU obtained were measured and compared. The results obtained have shown that the oxidative modification by POM/H2O2 can be considered as an approach to lignins upgrading for production of high reactive lignopolyols suitable in the field of polyurethane chemistry.

Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH center dot, ABTS(center dot+) and O-2(center dot-) antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed by in vitro experiment with human blood.

In the present investigation the growing and development ability of various annual and perennial plants to grow on model peat substrate artificially polluted with oil products in the range of concentrations from 1 to 5% was evaluated. The highest tolerance towards peat contamination by oil products has been demonstrated by three annual crops (maize, oat and lupine). These plants were tested for phytoremediation of polluted black soil from the area of oil refinery plant (Mazeikiai, Lithuania), which was treated by association of oil oxidizing bacteria up to residual concentration of the oil products of 4.5 %. The maize plants revealed the highest remediation ability: oil content in the soil decreased by 1.5 times in one month plant vegetation.

Analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) was used to analyze chemical composition of non-hydrolyzed residues (LHRs) obtained by three methods of bioethanol production: softwood acid hydrolysis (AH), separate enzymatic hydrolysis and fermentation (SHF), and simultaneous saccharification and fermentation (SSF). Complementary techniques, such as EPR- and FTIR-spectroscopy, and routine chemical analysis procedures were used for this study as well. The Py-GC/MS analysis of the LHRs has shown a higher efficiency of carbohydrates hydrolysis upon SSF process in comparison with SHF and AH processes. Comparison of chemical analysis results and data obtained by Py-GC/MS of LHRs brought the direct evidence of incorporation of carbohydrates-derived fragments into the lignin matrix and formation of so-called pseudo-lignin upon different stages of softwood processing. Modifications of lignin component of LHRs on various stages of the process of bioethanol production, such as oxidation and condensation reactions, cleavage of ether bonds and destruction of side propane chain, were revealed using Py-GC/MS.

The interaction of two types of lignins: Kraft lignin (KL), isolated according to the LignoBoost process (Sweden), and Alcell organosolv (OL) lignin (Canada), with 4,4’-diphenylmethane diisocyanate (MDI) in the dry dioxane media at 298 K was investigated. In the presence of dibutiltin dilaurate (DBTD) reaction followed the second order rate up to 43-56 % conversion. In these conditions the second order rate constants for both lignins are approximately 3.7-3.810 -4 l mol -1 s -1 . After that the negative deviation from the second order kinetic was observed. The complete NCO conversion in the case of KL takes more time than that of OL. The data of FTIR spectroscopy, element analysis and results of thermal analysis indicate the complete condensation of OH groups of both lignins with MDI, followed by crosslinked polyurethane (PU) formation.

Pyrolytic oils of different hardwood species were obtained in a two-stage ablative pyrolysis reactor. The GC/MS analysis of the pyrolytic oil has shown a different content of products of degradation of carbohydrates and lignin depending on the wood species. Pyrolytic oil were dispersed in water and separated to soluble and insoluble fractions. The fractions were characterised by the Py-GC/MS method. It is shown that the chemical composition of the water-soluble fractions differs from the composition of pyrolytic oils only insignificantly. In the composition of the water-insoluble fraction the amount of the products of degradation of carbohydrates decreases, while the content of monomeric phenolic compounds increases more then twice, and varies from 52.1 to 60.5% in the total sum of products for different wood species. The antioxidant properties, typical for lignin-containing preparations, were investigated by three independent methods. The results have shown that the water-insoluble fraction of pyrolytic oils, the so-called “pyrolytic lignin” can be regarded as a promising polymer antioxidant.

The main distinction of the novel technology from the traditional ones is application of filtration devices of multiple usage consisting of fibrous active carbon and an original film-fabric material and combination of the advanced granulated/tabletted carbon sorbents, which are characterized by ability to quick disintegration into particles of colloid size upon interaction with water that leads to the development of a large interface area and significant increase in adsorption activity towards different types of pollutants (suspended bacteria and viruses, chemical substances of inorganic and organic origin) and to form large flakes within a short period of time with their further aggregation and sedimentation. The use of the materials developed together with commercial disinfectants allows obtaining of drinking water from water polluted with such kinds of pollutants as phenols, pesticides, heavy metals, harmful microbes and viruses. The suggested procedure for water purification includes oxidation, sorption, coagulation and filtration stages and can be used in the case of emergency situation and in the regions with poor environment conditions.

Modification of technical lignosulphonates (LST), a large-scale by-product of the pulp-and-paper industry, with propylene (PO) and ethylene oxides (EO) in media of glycerol (GLC) or ethylene glycol (EG) allows producing of lignosulphonate oligoethers (LSOE) with the hydroxyl number value 420-495 mg KOH/g and viscosity 800-4500 mPa.s. The high reactivity of LSOE to isocyanate makes it possible to produce polyurethane (PU) materials, including rigid polyurethane (PUR) foam and PU binders, with a wide range of application. The increasing ability of LSOE to form associates in solutions as a result of oxyalkylation, in comparison with the initial LST, allows to apply LSOE successfully as a modifier of oxyethylcellulose hydrogels, used in secondary petroleum production. As a result, an increase in gel's salt and thermal stability has been achieved.The replacement of polyethyleneglycol and glycerol, traditionally used as components of water-based hydraulic liquids by LSOE, makes it possible to lower the pour point of water-based hydraulic liquids and to decrease the dependence of their viscosity on temperature.

Analytical pyrolysis (AP) as well as chemical analysis, ESR, FTIR and UV/VIS-spectroscopy has been used to characterize effects of modification of industrial lignins (hydrolysis lignin and kraft lignin) with silicon-containing oligomers on their transformation in soil planted with timothy grass (Phleum pratense). Using Py-GC/MS it was shown that carbohydrate-originated admixtures of non-modified hydrolysis lignin were degraded preferentially during the first vegetation season (12 weeks), whereas the degradation of lignin moieties was developed during the second vegetation season (60 weeks of incubation). The modification of both hydrolysis and kraft lignins with Si-oligomers promotes degradation of lignin from the earlier stage of incubation in soil. After the first 12 weeks of incubation the G/S ratio in products from pyrolysis of residual Si-modified hydrolysis lignin has increased almost twice, whereas for non-modified hydrolysis lignin this ratio has not changed. At the same time, Si-modification prevented oxidation of lignin during the whole incubation duration: yields of CO2 and carbonyl-containing compounds upon pyrolysis of residues of Si-modified hydrolysis lignin were lower in comparison with those for the residues of non-modified lignin. Simultaneously with degradation, condensation of the lignins residual structure occurred, moreover in Si-modified hydrolysis lignin up to a higher extent than for non-modified lignin. For non-modified kraft lignin an aromatization and condensation of the structure was observed at earlier incubation time in comparison with hydrolysis lignin, and the effect of Si-modification in this case is not as potent as it is observed for hydrolysis lignin. Py-GC/MS data were used to define relationships between the changes in chemical structure of lignins and numbers of microorganisms in the timothy grass rhizosphere. Significant positive correlations were found between the development of humus-degrading bacteria population and the relative abundance of carbon dioxide in the lignin pyrolysis products as well as between numbers of humus-degrading fungi population and relative abundances of guaiacol and syringol.

A novel nanoporous (pore size of 11 nm in average, BET surface area of 30 m(2)/g, pore volume of 300 mm(3)/g) hybrid inorganic-organic material was synthesized using the solid-phase interaction at room temperature of plant-originated phenylpropanoid polymer lignin and a Keggin-type heteropolyanion [SiMo12O40](4-). The partly reduction of Mo(VI) to Mo(V) and complexes formation between lignin and polyanion have been established by EPR, FT-IR and Raman spectroscopy. The XRD pattern and FT-IR spectrum of the hybrid material and indicates that [SiMo12O40](4-) anion maintains the Keggin structure.

The present work is devoted to the estimation of the effect of phosphoric acid and Fe3+ ions on the 1,6-anhydrosaccharides levoglucosan (LG) and levoglucosenone (LGone) contents in volatile products obtained from wood and microcrystalline cellulose by analytical pyrolysis. It was shown that the LG and LGone contents can be influenced by the pre-treatment. Iron was introduced into the biomass either by soaking in iron(III) sulfate solution alone or in the presence of ammonium, a treatment, in the course of which iron oxihydroxide is formed. It was demonstrated that a previous decationization of wood plays an important role for the subsequent results of Fe3+ ion treatment.The 1,6-anhydrosaccharides content in volatile products and the ratio of LG/LGone is governed by the phosphoric acid concentration. The same is true for cellulose soaked by iron sulfate: at higher concentration, the LGone content increases and the LG/LGone ratio decreases. The mechanism of the action of iron ions depends on the iron species formed upon the cellulose-containing raw materials pre-treatment procedures with iron sulfate. Upon pyrolysis, the adsorbed iron sulfate increases the amount of both LG and LGone in volatile products through the acidic catalysis mechanism owing to sulfate anions activity. The pre-treatment by the ion-exchange method could be considered as an efficient technique for obtaining the biooil containing levoglucosan in high content: 44.8% from cellulose and 27.3% from wood. The results are interpreted based on the quantitative evaluation of the pyrograms and the ESR spectra of the treated wood. (C) 2005 Elsevier B.V. All rights reserved.