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Depolymerization of lignin by pyrolysis has been identified as a viable route to produce renewable fuels and biobased platform chemicals. Herein we report the pyrolysis of LignoBoost lignin in a molten salt consisting of ZnCl2-KCl-NaCl (60:20:20 mol ratio) in a g-scale reactor set-up with a focus on the liquid phase yields and composition. The effects of relevant process parameters such as temperature (250–450 °C), reaction time (10–50 min), and N2 flow rate (10–30 mL min−1) on the product yields were elucidated using design of experiments. The highest bio-oil yield was 47.1 wt% (450 °C, 10 min) and the yield of organics in the bio-oil at this condition was 24 wt% (on lignin intake), the remainder being water. The latter is considerably higher than found for an experiment at similar conditions without salt (16 wt%). Temperature and reaction time were shown to have the largest effects on bio-oil yield. Prolonged reaction times resulted in higher amounts of gas phase components (H2, CO2) and water, and a reduced amount of solid products. Statistical analyses and validation experiments showed that the experimental product yields are in good agreement with the predicted values from the model. The properties and molecular composition of the liquid products were determined using various analytical techniques and reveal that the presence of a molten salt during pyrolysis has a positive influence on the composition of the liquid phase like a higher level of depolymerization and higher selectivity to aromatic and phenolic monomers compared to thermal pyrolysis.

Pyrolysis is an important technology to convert lignocellulosic biomass to a renewable liquid energy carrier known as pyrolysis oil or bio-oil. Herein we report the pyrolysis of pigeon pea wood, a widely available biomass in the Philippines, in a semi-continuous reactor at gram scale. The effects of process conditions such as temperature (400-600 ◦C), nitrogen flow rate (7-15 mL min−1) and particle size of the biomass feed (0.5-1.3 mm) on the product yields were determined. A Box-Behnken three-level, three-factor fractional factorial design was carried out to establish process-product yield relations. Of particular interest is the liquid product (bio-oil), of which the yield was shown to depend on all independent variables in a complex manner. The optimal conditions for highest bio-oil yield (54 wt.% on dry feed intake) were a temperature of 466 ◦C, a nitrogen flow rate of 14 mL min−1 and a particle size of 1.3 mm. Validation of the optimized conditions proved that the average (n = 3) experimental bio-oil yield (52 wt.%) is in good agreement with the predicted value from the model. The properties of product oils were determined using various analytical techniques including gas chromatography-mass spectrometry (GC-MS), gel-permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (13C- and HSQC-NMR) and elemental and proximate analyses. The bio-oils were shown to have low ash content (0.2%), high heating value (29 MJ kg−1) and contain high value-added phenolics compounds (41%, GC peak area) as well as low molecular weight aldehydes and carboxylic acids. GPC analysis indicated the presence of a considerable amount of higher molecular weight compounds. NMR measurements showed that a large proportion of bio-oil contains aliphatic carbons (~60%), likely formed from the decomposition of (hemi)cellulose components, which are abundantly present in the starting pigeon pea wood. Subsequent preliminary scale-up pyrolysis experiments in a fluidized bed reactor (~100 gfeed h−1, 475 ◦C and N2 flow rate of 1.5 L min−1) gave a non-optimized bio-oil yield of 44 wt.%. Further fractionation and/or processing are required to upgrade these bio-oils to biofuels and biobased chemicals.

Current lignin fractionation methods use harsh conditions that alter the native lignin structure, resulting in a recalcitrant material which is undesired for downstream processing. Milder fractionation processes allow for the isolation of lignins that are high in &beta, aryl ether (&beta, O-4) content, however, at reduced extraction efficiency. The development of improved lignin extraction methods using mild conditions is therefore desired. For this reason, a flow-through setup for mild ethanosolv extraction (120 &deg, C) was developed. The influence of acid concentration, ethanol/water ratio, and the use of other linear alcohol co-solvents on the delignification efficiency and the &beta, O-4 content were evaluated. With walnut shells as model feedstock, extraction efficiencies of over 55% were achieved, yielding lignin with a good structural quality in terms of &beta, O-4 linking motifs (typically over 60 per 100 aromatic units). For example, lignin containing 66 &beta, O-4 linking motifs was obtained with an 80:20 n-propanol/water ratio, 0.18 M H2SO4 with overall a good extraction efficiency of 57% after 5 hours. The majority of the lignin was extracted in the first 2 hours and this lignin showed the best structural quality. Compared to batch extractions, both higher lignin extraction efficiency and higher &beta, O-4 content were obtained using the flow setup.

5-hydroxymethylfurfural (HMF), accessible from various feedstocks, represents an important renewable platform-chemical, precursor for valuable biofuels and bio-based chemicals. In this work, the continuous hydrogenation of an aqueous solution of HMF to give strategic monomers, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) was investigated in a continuous flow reactor adopting a commercial Ru/C (5 wt%) as catalyst. The influence of the main process variables on products yield and selectivity was studied and optimized. The highest BHMF and BHMTHF yields of 87.9 and 93.7 mol%, respectively, were achieved by tuning the catalyst contact time, keeping all other variables constant (temperature, pressure, hydrogen flow rate, initial HMF concentration). Intraparticle diffusion limitation for hydrogen and HMF was shown to occur at some of the tested conditions by performing the HMF hydrogenation with different catalyst particle sizes, confirmed by calculations. Constant catalyst activity was observed up to 6 h time-on-stream and then gradually reduced. Fresh and spent catalyst characterization showed no significant sintering and negligible leaching of ruthenium during time-on-stream. A decrease of the specific surface area was observed, mainly due to humin deposition which is likely the reason for catalyst deactivation. Catalyst performance could be restored to initial values by a thorough washing of the catalyst.

5-hydroxymethylfurfural (HMF) is one of the most important renewable platform-chemicals, a very valuable precursor for the synthesis of bio-fuels and bio-products. In this work, the hydrogenation of HMF to two furan diols, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF), both promising renewable monomers, was investigated. Three commercial catalysts, Ru/C, Pd/C and Pt/C, were tested in the hydrogenation of aqueous HMF solutions (2–3 wt%), using a metal loading of 1 wt% respect to HMF content. By appropriate tuning of the process conditions, either BHMF or BHMTHF were obtained in good yields, and Ru/C resulted the best catalyst for this purpose, allowing us to obtain BHMF or BHMTHF yields up to 93.0 and 95.3 mol%, respectively. This catalyst was also tested for in the hydrogenation of a crude HMF-rich hydrolyzate, obtained by one-pot the dehydration of fructose. The influence of each component of this hydrolyzate on the hydrogenation efficiency was investigated, including unconverted fructose, rehydration acids and humins, in order to improve the yields towards each furan diol. Moreover, ICP-OES and TEM analysis showed that the catalyst was not subjected to important leaching and sintering phenomena, as further confirmed by catalyst recycling study.

Bio-aromatics (benzene, toluene, xylenes, BTX) were prepared by the catalytic pyrolysis of six different black liquors using both in situ and ex situ approaches. A wide range of catalysts was screened and conditions were optimized in microscale reactors. Up to 7 wt % of BTX, based on the organic fraction of the black liquors, was obtained for both the in situ and ex situ pyrolysis (T = 500–600 °C) using a Ga-modified H-ZSM-5 catalyst. The in situ catalytic pyrolysis of black liquors from hardwood paper mills afforded slightly higher yields of aromatics/BTX than softwood black liquors, a trend that could be confirmed by the results obtained in the ex situ catalytic pyrolysis. An almost full deoxygenation of the lignin and carbohydrate fraction was achieved and both organic fractions were converted to a broad range of (substituted) aromatics. The zeolite catalyst used was remarkably stable and even after 100 experiments in batch mode with intermittent oxidative catalyst regeneration, the yields and selectivity toward BTX remained similar. The ex situ pyrolysis of black liquor has potential for large-scale implementation in a paper mill without disturbing the paper production process., Conversion of black liquors to biobased aromatics show the potential of black liquors for synthesis of such aromatics.

The capture of large amounts of CO2 from power plants and other large CO2 point sources has become relevant within the concept to mitigate CO2 emissions via carbon capture and storage. The objective of this study was to investigate the impact of some major impurities found in the CO2 stream captured from power plants and other large point sources on the liquid-vapor phase change compared to pure CO2. The study contributes to a better understanding of how and within which boundary conditions transmission of impure CO2 from an emission and capture point to a storage location can be realized.A set up was constructed to provide the experimental data needed to trace the phase diagrams of the CO2-impurities mixtures. The data show an expansion of the liquid-vapor phase envelope and a start of boiling (in liquid) or condensation (in vapor) at relatively higher pressures. The experimental data were later used to assess the capabilities of three mixture models: the Soave-Redlich-Kwong cubic equation of state, the GERG-2008 model, and the EOS-CG model. (C) 2013 Elsevier B.V. All rights reserved.

In commercial methanol production from syngas, the conversion is thermodynamically limited to 0.3-0.7 leading to large recycles of non-converted syngas. This problem can be overcome to a significant extent by in situ condensation of methanol during its synthesis which is possible nowadays due to the availability of highly active catalysts allowing for lower reactor temperatures. For the first time, in situ methanol condensation at 20 MPa and 473 K was demonstrated visually in a view cell. The condensation of reaction products (mainly methanol and water) drives the equilibrium reactions nearly to completion, as is demonstrated experimentally in a packed bed reactor and supported by thermodynamic calculations. Contrary to conventional methanol synthesis, once-through operation becomes possible avoiding recycling of unconverted syngas, which can be economically beneficial for industrial stakeholders. (C) 2012 Elsevier Ltd. All rights reserved.

gamma-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. We here report an experimental study on the catalytic hydrogenation of levulinic acid (LA) in water to GVL in a packed bed reactor using supported Ru catalysts (carbon, alumina, and titania) with particle sizes in the millimeter range (C-LA,C-0 = 1.2 mol/L, LA feed = 1 mL/min, H-2 feed = 30 mL/min, 90 degrees C, 45 bar, and WHSV = 30 of g(feed)/g(cat).h). Intraparticle diffusion limitations for hydrogen and LA were confirmed by performing LA hydrogenation experiments with different catalyst particle sizes (0.5 wt % Ru/C) and supported by calculations. The best performance was obtained with Ru/C, showing high LA conversion during 6 h on stream with negligible deactivation. Ru/Al2O3 was found to be less active, and stability was also considerably reduced due to the reactivity of the support. Ru/TiO2 was considerably less reactive, though stability was better than that for the alumina based counterpart. A long duration test (52 h) for Ru/C (0.5 wt % of Ru) showed a small though significant reduction in LA conversion (from 95 to 82 mol %). Catalyst characterization studies showed a significant decrease in the specific surface area of the catalyst (from 1110 m(2)/g to 390 m(2)/g) and sintering of the Ru particles (TEM-HAADF).

Experimental trials have been undertaken to determine interfacial area for mass transfer in 5cm and 25cm diameter annular centrifugal contactors. All trials used 30% TBP in Exxsol D80 diluent, with extraction of HNO3 being studied at varying flowrates and volumetric flow ratios. Droplet size was determined using a laser reflectance probe.Results from the 5cm rig showed two different regions of operation and the value of the dimensionless constant (K) in the Kolmogoroff expression was estimated to be 0.28 for O/A ratios below 2.5 and 0.30 above 2.5. From the 25cm rig trials K was estimated to be 0.26.

The invention relates to a process for the pyrolysis of biomass, the process comprising the steps of a) providing the biomass, b) providing a salt, c) combining the biomass and the salt, d) feeding the combined biomass and salt to an extruder, e) heating the combined biomass and salt in the extruder, thereby melting the salt if solid, and dissolving and/or dispersing the biomass in the molten salt, f) transporting the mixture through the extruder at pyrolysis conditions, thereby creating liquid pyrolysis products, gases, and char, g) removing the liquid pyrolysis products, gases, char and salt from the extruder, and h) separating the liquid pyrolysis products from the salt, the gases and the char.