Liquefaction Yield Research Articles

Efficient preparation of β-1,3-glucooligosaccharides by microwave-assisted hydrothermal degradation of curdlan and preliminary exploration of its antibacterial activity

The study focuses on the efficient production of curdlan β-1,3-glucooligosaccharides (CDOS) through microwave-assisted hydrothermal hydrolysis of curdlan. The optimal condition was identified as 170 °C and 30 min, resulting in a curdlan liquefaction yield of over 96%, mainly contains CDOS along with minor amounts of glucose and 5-hydroxymethylfurfural (5-HMF). Oligosaccharides with a low degree of polymerization (DP), specifically DP2 to DP6, were isolated. The yields for DP2 to DP6 were 15.87%, 8.33%, 6.00%, 3.13%, and 1.83%, respectively, with purities over 70%. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis demonstrated that the dense triple helix structure of the crystalline structure was disrupted during degradation. Additionally, CDOS at a concentration of 2.5 mg/mL partially inhibited the growth of Escherichia coli. This study concludes that the combination of microwave-assisted hydrothermal hydrolysis with gel filtration chromatography provides an efficient method for producing and purifying CDOS.

Liquefaction optimization of grape pulp using response surface methodology for biopolyol production and bio-based polyurethane foam synthesis.

Both environmental and economic disadvantages of using petroleum-based products have been forcing researchers to work on environmentally friendly, sustainable, and economical alternatives. The purpose of this study is to optimize the solvothermal liquefaction process of grape pomace using response surface methodology coupled with a central composite design. After investigating the physicochemical properties of the liquified products (biopolyol) in detail, a bio-based rigid polyurethane foam (RPUF) was synthesized and characterized. The hydroxyl and acid numbers and viscosity values of all the biopolyols were analyzed. According to variance analysis results (%95 confidence range), both the reaction temperature and catalyst loading were determined as significant parameters on the liquefaction yield (LY). The model was validated experimentally in the following reaction conditions: 4.25% catalyst loading, 50 min reaction time, and 165 °C reaction temperature, which yields an LY of 81.3%. The biopolyols produced by the validation experiment display similar characteristics (hydroxyl number: 470.5 mg KOH/g; acid number: 2.31 mg KOH/g; viscosity: 1785 cP at 25 °C) to those of commercial polyols widely preferred in the production of polyurethane foam. The physicochemical properties of bio-based foam obtained from the biopolyol were determined and the thermal conductivity, closed-cell content, apparent density, and compressive strength values of bio-based RPUF were 31.3 mW/m·K, 71.1%, 33.4 kg/m3, and 105.3 kPa, respectively.

Liquefaction pathway of corn stalk cellulose in the presence of polyhydric alcohols under acid catalysis

In this paper, the experiment of cellulose from corn stalk using 1, 2-propylene glycol (PG) and diethylene glycol (DEG) liquefaction catalyzed by phosphoric acid at atmosphere pressure was carried out. The effect of reaction time on the structural changes of cellulose in the liquefaction process of polyhydric alcohols was investigated, aiming at understanding the mechanism of cellulose liquefaction reaction under the action of acid catalyzed polyhydric alcohols. It was found that the liquefaction yield increased first and then decreased with the extension of reaction time, and reached the highest at 150 min (99.34 %). In the phase of increasing liquefaction yield, cellulose was degraded and translated into glucose, which was then converted into plenty of glycosides with PG/DEG. These glycosides were further converted into low molecular weight (LMW) substances such as hydrocarbons, acids, alcohols, esters, ketones, and ethers. At this time, the biofuel contained 70 %–85 % compounds with carbon number less than 25 and 5 %–10 % compounds with carbon number more than 25. As the prolongation of reaction time (after 150 min), quantities of unstable free radicals formed by cellulose degradation could combine with each other or with hydrogen atoms provided by PG/DEG to produce relatively stable macromolecular substances. That is, the polydispersity (Mw/Mn, abbreviated Ð = 1.28) of the generated biofuel at this stage no longer decreased. However, liquefaction residue produced at 240 min had changed essentially, which was completely different from the liquefaction residue produced in the early stage of liquefaction. In conclusion, this paper revealed the partial reaction process of cellulose by studying the structural changes in the liquefaction process of polyhydric alcohols, which laid a theoretical foundation for exploring the liquefaction mechanism of cellulose.

Hydrothermal liquefaction of Salix psammophila in the presence of ionic liquid and water

Salix psammophila was converted to value-added chemicals in the presence of 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and water by the hydrothermal liquefaction method. [Bmim]Cl acted as both liquefier and catalyst, while water served as both co-solvent and reactant. The optimal reaction parameters for the highest liquefaction yield were determined by an orthogonal experiment. The possibility of application of the recycled [Bmim]Cl was investigated. FT-IR spectra results of the fresh used, the firstly reused, and the secondary reused IL [Bmim]Cl confirmed the high stability of [Bmim]Cl. Moreover, an explanation of the possible liquefaction mechanism for S. psammophila was also provided. This study may provide fundamental data for S. psammophila conversion and application.

Comparison of two-stage and single-stage liquefaction schemes for their effect on conversion and liquid yield of two low rank coals

Balancing the rates of coal radical fragments’ generation and hydrogen donation is crucial to inhibit the radical fragments’ condensation for a high oil yield and low hydrogen consumption in direct coal liquefaction (DCL). Two-stage liquefaction (TSL) has been proposed to be effective for balancing these rates under mild conditions but little work can be found in the literature on the comparison of TSL with single-stage liquefaction (SSL). This work studies direct liquefaction of two low-rank coals (NMH and SW) of very different volatile content under various TSL and SSL schemes in systems with different hydrogen donation ability. The coal conversion and products yield in different liquefaction schemes are correlated with their organic structure characterized by 13C NMR and predicted by a structure model. It is found that for the total 40 min liquefaction, the TSL scheme with 10 min at 420 ℃ followed by 30 min at 455 ℃ results in the highest liquid yield and lowest hydrogen consumption per liquid yield when the coal is very active but the hydrogen donation ability is insufficient. Otherwise, SSL at 455 ℃ is preferred. The coal conversion, liquid yield and hydrogen consumption per liquid yield of NMH under above TSL scheme at coal:THN= 1:2 are 85.5 wt%, 55.9% and 48.4 mmol-H/g-Liquid, respectively.

Low-Calorie Coal Liquefaction Products as an Alternative Fuel Oil

Liquefaction of low-rank coal has been done to optimize the utilization of low-rank coal, which is less economical for obtaining alternative fuel oil. Coal samples were taken from the Bukit Pinang coal mine, Samarinda Ulu, East Kalimantan. Coal was liquefied using the NEDOL procedure at PUSPITEK, Serpong, South Tangerang, Indonesia. This Bukit Pinang coal liquefaction produces five fractions consisting of Naphta, Light Oil (LO), Middle Oil (MO), Heavy Oil (HO), and Coal Liquid Bottom (CLB) fractions. The liquefaction yield was dominated by the HO and CLB fractions (> 50% by weight). The naphtha, MO and LO fractions were fractionated using SiO2 GF254 Thin Layer Chromatography (TLC) plate. It produced aliphatic and aromatic hydrocarbon fractions. Aliphatic hydrocarbon fractions were analyzed using a Gas Chromatography-Mass Spectrometer (GC-MS), while the aromatic hydrocarbon fractions were not analyzed. Mass spectrum studies showed that the components consisted of n-alkanes, isoalkanes (branched alkanes), cycloalkanes and alkyl cycloalkanes. The aliphatic hydrocarbon components resulting from the liquefaction of low-rank coal showed its equivalence with the components that make up fuel oil. Therefore, this coal liquefaction can be suggested as an optimization for low-rank coal, which is less economical.

Novel Two-Step Process in Cellulose Depolymerization: Hematite-Mediated Photocatalysis by Lytic Polysaccharide Monooxygenase and Fenton Reaction.

To transform cellulose from biomass into fermentable sugars for biofuel production requires efficient enzymatic degradation of cellulosic feedstocks. The recently discovered family of oxidative enzymes, lytic polysaccharide monooxygenase (LPMO), has a high potential for industrial biorefinery, but its energy efficiency and scalability still have room for improvement. Hematite (α-Fe2O3) can act as a photocatalyst by providing electrons to LPMO-catalyzed reactions, is low cost, and is found abundantly on the Earth’s surface. Here, we designed a composite enzymatic photocatalysis–Fenton reaction system based on nano-α-Fe2O3. The feasibility of using α-Fe2O3 nanoparticles as a composite catalyst to facilitate LPMO-catalyzed cellulose oxidative degradation in water was tested. Furthermore, a light-induced Fenton reaction was integrated to increase the liquefaction yield of cellulose. The innovative approach finalized the cellulose degradation process with a total liquefaction yield of 93%. Nevertheless, the complex chemical reactions and products involved in this system require further investigation.

Liquefaction and chemical composition of walnut shells

AbstractThe cultivation of walnut (Juglans regiaL.) for the exploitation of the fruit has been increasingly recognized worldwide; therefore, it is important to valorize a large amount of biomass from walnut shells (WS), where liquefaction may play an important role. This work intends to contribute to an improved understanding of the best uses for this material. The assays were made with a binary mixture of ethylene glycol and glycerol (1:1 v/v) as solvents, catalyzed by sulfuric acid. The tested parameters were as follows: particle size >0.420–0.177 mm, temperature 140–200°C, and reaction time between 15 and 60 min. The initial dried material, the liquefied material, and the resulting solid residue were analyzed by FTIR-ATR for polyol characterization. The results showed that WS are mostly composed of lignin with 35.0% and polysaccharides, 30.0% cellulose and 24.9% hemicelluloses. High-lignin content indicated that WS might be used as a bio-fuel or adhesives. Extractives represent 10.2% with almost half (4.6%) of polar extractives. The best conditions to attain the optimal liquefaction yield were 160°C, 30 min, and 0.420–0.250 mm particle size, for the tested parameters. FTIR spectrum of the liquefied material is very different from the original material, and solid residue spectra seem to indicate that there is higher liquefaction of polysaccharides when compared with lignin since there is a higher absorption at 1,600 cm−1and lower absorption at 1,040 cm−1and that liquefied compounds are probably in smaller molecules.

Eco Valorization of Eucalyptus globulus Bark and Branches through Liquefaction

Eucalyptus globulus forest residues, bark, and branches, were characterized by wet chemistry methods and involved in the liquefaction process using a glycerol-ethylene glycol reaction mixture (1:1, v/v) catalyzed by strong mineral acid (3% H2SO4) or strong mineral base (6% KOH). The effect of the reaction conditions (temperature and duration) and the particle size on the yield of liquefied products have been evaluated. Acid catalysis revealed remarkably higher yields (25–50%) than when using basic catalyst. It was considered that bark was more vulnerable to liquefaction with respect to particle size than branches. Too high temperatures (>180 °C) are not advantageous regarding the liquefaction yields and, therefore, temperatures around 160–180 °C would be preferable. The best yield for the bark sample (>80 mesh fraction) was obtained at 180 °C for 60 min (61.6%), while for the branches the best yield was obtained at 160 °C for 60 min (62.2%). Under compromised conditions (180 °C for 60 min), the fine fraction (>80 mesh) of bark and branches did not show significant differences between their liquefaction yields and can be processed together while adjusting the suitable processing time. The main advantage of the use of these residues instead of solid wood is that it would bring the Forest managing companies a much higher income for their wastes that are usually burned and the use of lignocellulosic materials in detriment of petroleum-based materials for the production of polymers would make industry less dependent on oil prices fluctuations.

Plasma-electrolytic liquefaction of human waste for biofuels production and recovery of ammonium, chlorine and metals

Sustainable production of value-added fuels and chemicals from biomass faces enormous challenges for integration in zero-carbon-emissions technologies and circular economy. In this work, green and renewable solvents, polyethylene glycol 200 and glycerol, were used in a plasma-electrolytic liquefaction (PEL) system to electrically liquefy human feces in the absence of a catalyst. It is demonstrated that the plasma ignition during the liquefaction accelerated the conversion of feces (85.67% liquefaction yield within 12 min), and the intrinsic heating features of the PEL greatly reduced the energy consumption. The obtained biocrude oil at the optimized conditions contained 10.53% aldehydes, 5.39% ketones, 18.48% cyclic oxygen-containing compounds and others, with a high heating value of 28.10 MJ/kg. Further analysis of the PEL-converted products reveals that most of the chlorine in the feces was gasified, the metals were extracted into the solid residue, while ammonia was released. An evaluation of the developed plasma electrolytic feces liquefaction process was carried out and favorably compared with common liquefaction methods. Overall, the proposed approach may provide a new avenue for clean chemical production and sustainable resource recovery from human waste under benign process conditions.

Experimental study on rotary triboelectric separation of low-rank coal macerals with surface modification

The enrichment of vitrinite can enhance the oil yield and conversion rate in low-rank coal liquefaction. The work evaluated the effects of surface modification on the rotary triboelectric separation of macerals. Permittivity and charge–mass ratio analysis of vitrinite and inertinite under various modified conditions demonstrated that kerosene and diesel were excellent modifiers since they keep the permittivity of macerals at a low level. The largest difference in triboelectric charge of vitrinite and inertinite was obtained when 3.0 kg/t kerosene was adopted as modifier. Rotary triboelectric separation of untreated low-rank coal indicated that the optimal separation, i.e., a vitrinite content of 65.45% and a recovery of 69.89%, was obtained at a feed rate of 1.5 g/s, a friction wheel speed of 3000 rpm, and a separation voltage of 30 kV. Under the optimum operating conditions, the optimal rotary triboelectric separation under surface modification, i.e., a vitrinite content of 69.78% and a recovery of 73.52%, was achieved when the coal was treated by 3.0 kg/t kerosene. The results demonstrated that surface modification significantly improved the rotary triboelectric separation by changing the surface electrical properties of macerals, while the excessive dosage of the modified reagent was unfavorable to achieving optimal separation.

Hydrothermal liquefaction of Chlorella vulgaris and catalytic upgrading of product: Effect of process parameter on bio-oil yield and thermodynamics modeling

Replacing fossil fuel sources with biofuels is one way to degrade greenhouse gas issuance. Recently, the interest, effort, and investment of researchers around the world in biofuel technology, has been focused on microalgae. The aim of the present work was focused on optimizing the biocrude yield of hydrothermal liquefaction (HTL) of Chlorella vulgaris. The effect of temperature, reaction time and the weight ratio of feedstock in different conditions of hydrothermal liquefaction process has been investigated. Optimization of bio-oil performance was done applying design expert software and response surface method (central composite design). The consequences show that the highest yield of bio-oil was obtained from Chlorella vulgaris (56.21% by weight) at 287 °C, reaction time of 40 min, and microalgae to water ratio of 0.07 Analysis of variance (ANOVA), suggests that the liquefaction temperature and reaction time plays the influential role in the bio-oil yield. Ni-Mo/Al2O3 was applied as catalyst for upgrading Bio-oil. The amount of sulfur in bio-oil have completely removed and HHV increased 7% (41.11 MJ/Kg) by using catalyst. Moreover, GC/MS analysis illustrates the number of nitrogenous compounds in bio-oil using Ni-Mo/Al2O3 was reduced, so that the amount of pyrazine was changed from 4.25% to 2.10% and pyrrole from 4.75% to 3.11%. To thermodynamics modeling and predict the phase behavior of the liquefaction process, manipulation of the UNIFAC coefficients equation was model to minimize the Gibbs free energy. The theoretical model had a 9.8% prediction error. This generation of bio-oils is expected to be good support for biofuels.

A novel strategy to simultaneously enhance bio-oil yield and nutrient recovery in sequential hydrothermal liquefaction of high protein microalgae

Advances in sequential hydrothermal liquefaction (SEQ-HTL, or two-step HTL) is limited by its low bio-oil production and enormous aqueous phase (AP) byproduct.The objective of this study was to integrate AP recirculation and fungal-microalgal cultivation with the SEQ-HTL to simultaneously improve bio-oil yield, energy recovery, and nutrient recovery. Specifically, AP from the first step (SI-AP) of SEQ-HTL was used to culture microalgae and fungi for nutrient recovery, and AP from the second step (SII-AP) was recycled four times as reaction solvent to enhance bio-oil yield. Interestingly, the SI-AP showed excellent biodegradability, and the complementary cultivation of fungi and algae has tremendous potential to recover nutrients. For example, 0.96 g/L fungi biomass and 87.71% chemical oxygen demand (COD) removal rate were obtained by fungi cultivation in SI-AP, and 1.35 g/L biomass and 63.80% ammonia nitrogen (NH4-N) removal rate were received by microalgae cultivation in SI-AP. The difference of dissolved organic matter in SI-AP and the AP from conventional HTL (HTL-AP, inhibited microalgae significantly) pointed out unsaturated substances and lignins/carboxylic-rich alicyclic molecules substances might be the primary factor inhibiting microalgae growth. During SII-AP recirculation, the yields of bio-oil (SII-Oil) and hydrochar (SII-Char) increased from 16.00% to 28.65% and 2.93% to 5.66%. 32.96–53.08% C and 15.93–24.00% N in SII-AP were recovered and transferred into SII-Oil and SII-Char. A series of characterizations showed that the increased bio-oil formation was mainly the transformation of amines, glycerol, alcohols, acetic acid, and amino acid fragments from the AP into the oil phase via Maillard reaction, Michael addition reaction and acylation. Overall, the novel strategy could improve the economic feasibility of processing high-protein microalgae biomass using the SEQ-HTL technique and is promising to the industrial applications of microalgae.

Catalytic depolymerization of the dealkaline lignin over Co–Mo–S catalysts in supercritical ethanol

In this work, lignin depolymerization was examined over CoMo sulfide catalysts supported on different carriers in supercritical ethanol system. The temperature, time, MoS2 and carrier effects on the lignin depolymerization were investigated. 95.76% liquefaction yield with negligible char was achieved over Co–Mo–S/ZrO2 at 340 °C for 150 min. The liquid product was mainly composed of C4–C8 alcohols, C4–C10 esters and C7–C10 aromatic compounds. The synergistic effect of active sites and acid-base sites on support played an important role in lignin depolymerization. Furthermore, the Co–Mo–S/ZrO2 catalyst is reusable with 8% loss in liquefaction yield after 5 cyclic runs. We believe that acid/base carriers or additives that can promote the medium to generate abundant free radicals or ions to replace external hydrogen pressure are one of the prospects for the design of depolymerization lignin catalysts.

Effect of co-liquefaction of lignin and laminaria saccharina on optimization of bio-oil yield

• Co-liquefaction of Laminaria saccharina with lignin is studied. • The synergistic effect is negative in most mild and lignin-rich conditions. • The synergistic effect is positive in severe and lignin-poor conditions. • Residence time showed an impact on bio-oil quality. • Co-liquefaction synergistically enhanced the bio-oil quality at specific conditions. Hydrothermal liquefaction (HTL) is a valuable technology to convert and use wet biomass feedstocks. Lignin, waste from the paper industry and the main component of lignocellulosic biomass, is co-liquefied with laminaria saccharina, a commonly available seaweed in Norway. The aim is to conduct statistical analysis and investigate the possibility of increasing bio-oil yield while lowering the char yield through a synergistic effect. The bio-oil and char yields are measured with different operating temperatures, residence times, and blending ratios (mass ratio of laminaria saccharina to the total mass) to find out the optimized process conditions for better outputs statistically. Response surface methodology (RSM) with a Box Behnken design methodology is used to optimize the liquefaction yields of laminaria saccharina, lignin, and the different blends of the two biomasses. The results explicitly revealed that the biomass blend's optimal bio-oil and char yields are 0.2513 (w/w 0 ) and 0.1791 (w/w 0 ) respectively at 573 K, 20 min with the blending mass ratio of 0.2. The synergistic effects on the bio-oil yield are detected at comparatively severe reaction conditions. According to the RSM, residence time does not affect bio-oil and char yields as much as the operating temperature and the blending ratio. Nevertheless, temperature, residence time, and blending ratio have different impacts on the functional groups. The temperature increase has helped increase the alcohol and phenolic compounds production while the residence time consumes the C-O bonds. The increase of laminaria saccharina mass ratio in the feedstock has improved the phenolic compounds, long-chain aliphatic hydrocarbons, carboxylic acids, ketones, aldehydes, and esters in the bio-oils. Co-liqueafctio has produced bio-oil with significantly lower N content than from bio-oil produced from laminaria saccharina liquefaction.

Investigation of the improvement of Sivas-Kangal lignites liquefaction product yields

In recent years, converting and using coal into the most suitable product according to its properties has emerged as a modern approach. Among the main processes applied to coal are low and high-temperature carbonization, gasification and liquefaction. In coal liquefaction, coal is broken down into free radicals using hydrogen donor solvent and catalyst under high temperature and pressure conditions. Later, these radicals can be used in the production of both liquid fuel and chemical raw materials by being saturated with hydrogen. This study aims to improve the yields of Sivas-Kangal lignite liquefaction products (char, preasphaltene, asphaltene, oil-gas). For this purpose, firstly raw coal, then spiral enriched clean coal liquefaction experiments were carried out. The chemical characterizations of the obtained products were determined by proximate and ultimate analysis. The composition of the oil was identified by GC-MS. As a result of the enrichment, the char yield decreased by 16.5% whereas the oil+gas yield increased by 14.64%. Total conversion increased from 31.74% to 48.24%. It has been concluded that the enrichment process has a positive effect on the liquefaction yields.

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Sodium-rich coals are suitable raw materials for direct coal liquefaction (DCL). However, sodium species in coals, especially exchangeable ones, can significantly reduce oil yield. In this work, to increase oil yield in direct liquefaction of sodium-rich coals, a feasible method using organic solvents to pretreat sodium-rich coals is proposed. Initially, sodium-rich coal was thermally treated with tetralin or 1-methylnaphtalene. Then, raw coal and all the treated coals were liquefied under the same conditions to evaluate the effects of thermal treatment on structural changes of coal molecules and oil yield. The results show that surface areas of the treated coals increased to 7.86 m2/g at most, which was favorable for combination between hydrogen and coal molecules during the DCL process. More importantly, the content of hydrogen in the treated coals was 0.95 wt% higher than that of raw coal on average, suggesting that treated coals could be later liquefied at mild conditions. Raman spectra demonstrated that during thermal treatment with tetralin, small aromatic ring systems in raw coal were prehydrogenated and transformed into nonaromatic systems. The pre-hydrogenation of the coal matrix definitely contributes to the increase in oil yield. In view of sodium species distribution in the treated coals, it is proved that tetralin can promote the transformation of exchangeable sodium species into other chemical forms more easily than 1-methylnaphtalene, which implies that tetralin has more positive effects on the increase of oil yield. Compared with that of raw coal, oil yields in direct liquefaction of the samples treated by tetralin increase by 14.0 to 15.1 wt% (daf).

Insight into acid-base bifunctional catalysts for microalgae liquefaction and bio-oil pyrolysis: Product characteristics, energy recovery and kinetics

The aim of this work was to enhance the hydrocarbon yield of Chlorella liquefaction and consecutive upgrading by a new class of acid-base bifunctional heterogeneous catalysts. A simple method of grafting -SO3H and -NH2 groups on the surface of clin/SBA-15 resulted in SO3H-SBA-15-NH2 catalysts. Oil yields of in situ and ex situ upgrading of LBO (liquefied bio-oil) were obtained on SO3H-SBA-15-NH2. On the optimized catalyst, the hydrocarbon yield was prompted to 68.34 %, the deoxygenation of noncatalytic LBO was up to 59.42 %, and the heat value of DSO (dual-stage oil) was 42.33 MJ/kg, which was analogous to that for petroleum crude. SO3H- played a predominant role in Chlorella decomposition, and NH2- showed a critical effect on LBO deoxygenation. The O/C ratio (0.086) of LBO was effectively reduced to 0.031−0.082 (in DSO). The activation energy of noncatalytic LBO to DSO pyrolysis was 92.42 kJ/mol at 70 % weight loss, which was attributed to the synergetic effect of acid and base sites on the catalyst. This ex situ catalytic approach reveals great potential for algae in fuel production.

Preliminary environmental and economic assessment of polyurethane foam produced by microwave-assisted liquefaction of riparian shrubs

The study aims to develop a full-scale plant to produce biobased PU foam from microwave liquefaction of riparian shrubs and to evaluate its environmental burden using a cradle-to-gate, scaled-up LCA approach. Life Cycle Inventory was built on experimental data for polyol synthesis by using Response Surface Methodology (RSM) to maximize the liquefaction yield. Bio-based PU foam was also compared with the petrochemical counterpart. Life Cycle Assessment was carried out using SimaPro 9.0 software and impacts were evaluated with EPD 2007 method. The results indicate that the methylene diphenyl diisocyanate production and the energy consumption for the liquefaction step are the major sources of impacts. Overall, the environmental superiority of biobased polyurethane cannot always be claimed with respect to their fossil counterpart. Finally, a simplified economic assessment showed that for the bio-based PU foam an interesting profitability could be obtained for a market price of 4.5 €/kg.

Chemical composition and study on liquefaction optimization of chestnut shells

Abstract Chestnut shell (CS) is a by-product of some food sector companies. The aim of this study was to test the suitability of this material to be liquefied with polyalcohols, optimizing the main liquefaction parameters in order to use the liquefied material for the production of high added value products. As the chemical composition of the fruit shell depends on the variation in the soil, climate, and species, the chemical composition of CS was determined. Liquefaction was performed with 50:50 ethyleneglycol:glycerol catalyzed by sulfuric acid. Different tests were carried out and several parameters were tested: particle size, temperature 130–190°C, and time 15–120 min. Chemical composition of CSs was determined. The main component found was lignin with 47.0%, which is higher than α-cellulose with around 20.5%, hemicelluloses 15.2%, and extractives in ethanol 8.8%. For the tested parameters, the best liquefaction yield was obtained at 190°C, 30 min, and a 40–60 particle size.