Steam gasification reactivity of char from rapid pyrolysis of bio-oil/char slurry

A slurry of bio-oil and char originating from wood pyrolysis is a promising gasifier feed-stock because of its high energy density. When such a slurry is injected into a high temperature gasifier it undergoes a rapid pyrolysis yielding a char which then reacts with steam. The char produced by pyrolysis of an 80 wt% bio-oil/20 wt% char mixture at heating rates of 100-10,000 °C/s was subjected to steam gasification in a thermogravimetric analyzer. The original wood char from the bio-oil production was also tested. Gasification was conducted with 10-50 mol% steam at temperatures from 800 to 1200 °C. Reactivity of the slurry chars increased with pyrolysis heating rate, but was lower than that of the original chars. Kinetic parameters were established for a power-law rate model of the steam-char reaction, and compared to values from the literature. At temperatures over 1000 °C, the gasification rates appeared to be affected by diffusional resistance.     

Energy-dense liquid fuel intermediates by pyrolysis of guayule (Parthenium argentatum) shrub and bagasse

Guayule is a perennial shrub grown in the southwestern United States that is used to produce high quality, natural rubber latex. However, only about 10% of the plant material is used for latex production; the remaining biomass, called bagasse, can be used for renewable fuel production. Fast pyrolysis of guayule, both whole shrub and bagasse was performed. From both feedstocks a very viscous, high energy content (∼30 MJ/kg) pyrolysis liquid (bio-oil) was produced in yields averaging over 60% without any catalyst. The properties and compositions of the bio-oils were found to be similar in the two feedstocks. Co-products, charcoal (20-30 wt%) and non-condensable gas (5-15%), were also dense and had a high energy content. Of the two feedstocks, the whole shrub yielded higher quantities of charcoal that also had a higher energy content than the charcoal produced from bagasse. As a result, the energy recovery, estimated as the percentage of the energy products, to energy input into the reactor was lower (60%) for guayule bagasse than for the whole shrub (73%). This notwithstanding, the bagasse is a more attractive feedstock for thermochemical conversion, not only because it is a residue from a primary process (latex extraction) that is on-site, but also because it has a high energy content. Moreover, it produces high quality pyrolysis products. Co-production of latex rubber from the whole shrub and renewable fuels from the residual bagasse by pyrolysis should improve the already positive economics of the guayule latex rubber industry.     

Structure-property relations of 55 nm particle-toughened epoxy

55-nm rubber particles significantly toughened two epoxy systems without loss of Young’s modulus, tensile strength and glass transition temperature. Transmission Electron Microscopy (TEM) showed that the nanoparticles are uniformly dispersed in matrix and have blurred interface with epoxy. 5 wt% rubber nanoparticles increased the critical strain energy release rate (G_1c) of Jeffamine D230 (J230)-cured epoxy from 175 J/m² to 1710 J/m², while the 10 wt% increased G_1c of diaminodiphenyl sulfone (DDS)-cured epoxy from 73 J/m² to 696 J/m². This is explained by comparing the surface-surface interparticle distance and total particle surface of nanocomposites with those of composites. The higher the matrix stiffness, the more nanoparticles needed for toughening. Although the 10 wt% J230-cured nanocomposite showed a 50% larger size of stress-whitened zone than the 5 wt% J230-cured nanocomposite, the 5 wt% nanocomposite showed a higher toughness. These nanoparticles were found to pose barriers to the vibration of crosslinked matrix molecules, leading to higher glass transition temperatures. While the matrix shear banding caused by nanoparticle expansion and growth is the major toughening mechanism for the J230-cured nanocomposites, the matrix plastic void growth and deformation are most probably the major mechanisms for the DDS-cured system. Under tensile loading, the nanoparticles in the DDS-cured epoxy created fibrils of 100-200 nm in diameter and 3-5 μm in length. TEM analysis in front of a subcritically propagated crack tip showed a number of voids of 30-500 nm in diameter in the vicinity of the crack, implying that rubber nanoparticles expanded, grew and deformed under loading. Unlike conventional epoxy/rubber composites in which all of the rubber particles in the crack front cavitated under loading, only a portion of the nanoparticles in this study expanded to create voids. Huang and Kinloch’s model developed from composites was found not fit well into these nanocomposites.     

Effect of crystallization temperature on the in situ valorization of physic nut (Jatropha curcus L.) wastes using synthetic HZSM-5 catalyst

Physic nut waste is selected as the biomass feedstock for fast pyrolysis as it is available in large amounts from biodiesel production in Thailand. The volatile matter and fixed carbon contents are 73.8% and 13.6% while ash contents are 5.8%. Carbon is the main element with 49.03 wt%. The oxygen content of 39.0 wt% is considerably high which could directly convert to the oxygenated pyrolysis liquid products. To decrease oxygenated compounds, HZSM-5 was used as a catalyst to upgrade pyrolytic products from fast pyrolysis using analytical pyrolysis–GC/MS method. The HZSM-5 catalyst was successfully synthesized by hydrothermal method at 160–180 °C for 24 h. The particle size, surface area, and pore diameter were 11.25–15.52 μm, 567–582 m²/g, and 21.78–26.11 Å, respectively. The pyrolysis was performed at 500 °C with the Jatropha wastes to catalyst ratio of 1:1–1:10. The presence of HZSM-5 contributed to eliminate the undesirable oxygenated compounds such as acids and ketones which could alleviate problem regarding acidity and instability in bio-oil. In addition, it enhanced significantly the yields of desirable hydrocarbon compounds. The increase in catalyst contents had an effect on the enhancement of hydrocarbons yields, and tended to promote deoxygenation and denitrogenation. At moderate biomass to catalyst ratio (1:5), HZSM-5 synthesized at 170 °C contributed to improve the hydrocarbon yields of 95%, including mainly toluene and xylene, which are valuable products because of their high heating value properties.     

Sugarcane bagasse as the scaffold for mass production of hierarchically porous carbon monoliths by surface self-assembly

The hierarchically porous carbon materials (HPCMs) with micro- and meso-porosity were prepared by surface coating and solvent evaporation-induced self assembly (EISA) using sugarcane bagasse as the scaffold. The triblock copolymer F127 and phenol-formaldehyde resin were used as mesostructural directing agent and carbon precursor, respectively. The microstructures in terms of morphology, pore texture, degree of graphitization, and thermal stability were characterized by scanning and transmission electron microscopy, nitrogen adsorption analysis, X-ray powder diffraction, and thermogravimetric analysis, respectively. The bulk morphology of HPCMs with hierarchically porous architecture can be retained after calcination at 1000 °C. Small and wide angel XRD patterns show 2-D hexagonal mesostructures and enhanced degree of graphitization. The specific surface areas of monolithic carbon materials are in the range 487-544 m² g⁻¹ with the micropore percentages of 66-67%. The thermal stability of HPCMs is enhanced by the strong interaction of hydroxyl groups of sugarcane bagasse with phenol-formaldehyde resins, and subsequently retains the highly ordered structures with pore size distributions centered at 0.5 and 3.2 nm. In addition, the bagasse-based HPCMs show good electrochemical property and the specific capacitances are in the range 190-234 F g⁻¹ at the scan rate of 5-50 mV s⁻¹. Results clearly show that the use of surface coating and EISA with sugarcane bagasse as the scaffold is an easy, effective and mass productive strategy for fabrication of HPCMs.     

Biofuels from waste fish oil pyrolysis: Continuous production in a pilot plant

Fast pyrolysis of waste fish oil was performed in a continuous pyrolysis pilot plant. The experiment was carried out under steady-state conditions in which 10 kg of biomass was added at a feed rate of 3.2 kg h⁻¹. A bio-oil yield of 72-73% was obtained with a controlled reaction temperature of 525 °C. The bio-oil was distilled to obtain purified products with boiling ranges corresponding to light bio-oil and heavy bio-oil. These biofuels were characterized according to their physico-chemical properties, and compared with the Brazilian-fuel specifications for conventional gasoline and diesel fuels. The results show that the fast pyrolysis process represents an alternative technique for the production of biofuels from waste fish oil with characteristics similar to petroleum fuels.     

Characterization of Mg-substituted hydroxyapatite synthesized by wet chemical method

Mg-substituted hydroxyapatite made up of needle-like and plate-like particles containing different amounts of Mg (between 0.21 wt% and 2.11 wt%) were prepared via wet chemical precipitation method of a homogenous suspension of Mg(OH)₂/Ca(OH)₂ and an aqueous solution of H₃PO₄. According to the data of Brunauer–Emmett–Teller method and field emission scanning electron microscopy, high specific surface area Mg-substituted hydroxyapatite was obtained. Specific surface area of as-synthesized powders increased from 94.9 m² g⁻¹ to 104.3 m² g⁻¹ with increasing concentration of Mg up to 0.64 wt%. Fourier transform infrared spectroscopy, X-ray powder diffraction, differential thermal analysis, and heating microscopy, were used to evaluate thermal stability and sintering behavior of synthesis products. Increase in concentration of Mg in synthesis products (≥0.83 wt%) promoted decomposition of Mg-substituted hydroxyapatite to Mg-substituted β-tricalcium phosphate after thermal treatment.     

Co-pyrolysis of sugarcane bagasse with petroleum residue. Part II. Product yields and properties

The main objective of the present work was to study the pyrolysis under vacuum of sugarcane bagasse combined with petroleum residue (PR), in terms of yields and properties of the products obtained. Important synergetic effects were observed during the co-pyrolysis in a fixed bed reactor leading to an increase in charcoal yield. Maximum charcoal and minimum oil yields were obtained with 15 wt% of PR mixed with bagasse. At this concentration, sugarcane bagasse charcoal is almost completely covered with PR-derived pyrolytic carbon. At concentrations higher than 15 wt%, hydrocarbon vapours interacted less with the bagasse charcoal. Consequently, an appreciable increase in oil yield was observed. The oils obtained are complex emulsions, which consist of oxygenated compounds originating from bagasse, hydrocarbons originating from PR and water. Oils obtained from feedstock with concentrations up to 15 wt% PR are stable emulsions consisting of PR-derived products in bagasse-derived oil. The oil obtained from the 30 wt% PR-bagasse blend is an unstable emulsion. However, the emulsion obtained at 50 wt% PR is again stable. In this emulsion, the PR-derived oil constitutes a continuous phase. This emulsion exhibits a carbon Conradson residue value (9 wt%) similar to that of PR-derived oil. A detailed characterization of the gas, oil and charcoal co-pyrolysis products is presented.     

An in situ reduction approach for bio-oil hydroprocessing

An in situ reduction treatment, combination of reduction and esterification, was investigated to refine bio-oil. Over Raney Ni and zeolites-supported noble metal (Pd and Ru) catalysts, the reductant formic acid decomposed into hydrogen and carbon dioxide, and then hydrogen reduced the bio-oil while compressible CO₂ dissolved in methanol to form a CO₂-CH₃OH expanded liquid. The results showed that Raney Ni and zeolites-supported Ru were highly active in this heterogeneous catalytic system. The reactions preformed at 150-230 °C for 5-7 h would give a better upgraded bio-oil with a high yield of 80-90 wt.%. The unsaturated components in bio-oil were reduced substantially without obvious coke formation, and the oxygen content was lowered by ca. 5 wt.%. Organic acids were converted into esters through the esterification with methanol, and the properties of hydrogenated bio-oil were improved: the pH value increased from 2.17 to ca. 4.5; the higher heating value approached to 22 MJ/kg, and the viscosity decreased from 5.31 to ca. 4.0 mm²/s.     

Effect of inorganic nanoparticles on mechanical property, fracture toughness and toughening mechanism of two epoxy systems

We investigated the effect of silica nanoparticles on the mechanical property and fracture toughness of two epoxy systems cured by Jeffamine D230 (denoted J230) and 4,4′-diaminodiphenyl sulfone (denoted DDS), respectively. Toughening mechanisms were identified by a tailor-loaded compact tension method which quantitatively recorded the deformation of a damage zone in the vicinity of a sub-critically propagated sharp crack tip. 20 wt% silica nanoparticles' fraction provided 40% improvement in Young's modulus for both systems; it improved the toughness of J230-cured epoxy from 0.73 to 1.68 MPa m^1/2, and for the other system improved from 0.51 to 0.82 MPa m^1/2. The nanoparticles not only stiffen, strengthen and toughen epoxy, but reduce the effect of flaws on mechanical performance as well. In both systems, nanosilica particle deformation, internal cavitation and interface debonding were not found, different to previous reports. This could be due to the various hardeners used or different identification techniques employed. The toughening mechanisms of the J230-cured nanocomposite were attributed to the formation and development of a thin dilatation zone and nanovoids, both of which were induced, constrained and thwarted by the stress fields of the silica nanoparticles. Regarding 10 wt% silica-toughen epoxy cured by J230, a thicker and shorter dilatation zone was found, where neither nanoparticles nor nanovoids were observed. With regard to the DDS-cured system, much less dilatation and voids were found due to the hardener used, leading to moderately improved toughness.     

Erosion behavior of SiC–WC composites

Dense silicon carbide (SiC) ceramics were prepared with 0, 10, 30 or 50 wt% WC particles by hot pressing powder mixtures of SiC, WC and oxide additives at 1800 °C for 1 h under a pressure of 40 MPa in an Ar atmosphere. Effects of alumina or SiC erodent particles and the WC content on the erosion performance of sintered SiC–WC composites were assessed. Microstructures of the sintered composites consisted of WC particles distributed in the equi-axed grain structure of SiC. Fracture surfaces showed a mixed mode of fracture, with a large extent of transgranular fracture observed in SiC ceramics prepared with 30 wt% WC. Crack bridging by WC enhanced toughening of the SiC ceramics. A maximum fracture toughness of 6.7 MPa*m^1/2 was observed for the SiC ceramics with 50 wt% WC, whereas a high hardness of 26 GPa was obtained for the SiC ceramics with 30 wt% WC. When eroded at normal incidence, two orders of magnitude less erosion occurred when SiC–WC composites were eroded by alumina particles than that eroded by SiC particles. The erosion rate of the composites increased with increasing angle of SiC particle impingement from 30° to 90°, and decreased with WC reinforcement up to 30 wt%. A minimum erosion wear rate of 6.6 mm³/kg was obtained for SiC–30 wt% WC composites. Effects of mechanical properties and microstructure on erosion of the sintered SiC–WC composites are discussed, and the dominant wear mechanisms are also elucidated.     

Pervaporation separation of toluene/n-heptane mixtures using a MSE-modified membrane: Effects of operating conditions

In this work, separation of toluene/n-heptane mixtures via pervaporation using a composite membrane was investigated. Effects of operating conditions such as feed temperature, feed composition and downstream pressure on the membrane performance were studied. Experimental results were obtained at different feed compositions (10–40 wt.%), operating temperatures (25–85 °C) and downstream pressures (2–32 mbar g). The membrane selectivity for toluene was found to be greater than that for n-heptane. According to the results, it was observed that increasing toluene concentration in the feed and operating temperature enhance the membrane swelling and increase the polymeric chain mobility. Therefore, feed concentration and temperature have the same effects on toluene selectivity and permeation flux of the membrane. Permeation flux increases and toluene selectivity decreases with increasing feed concentration and temperature. In contrary, the membrane performance enhances with decreasing downstream pressure. It was found out that for a feed with 10 wt.% of toluene, at a temperature of 85 °C and a downstream pressure of 2 mbar g, the highest PSI value of 18.371 kg/m² h (in which permeation flux = 4.610 kg/m² h and toluene selectivity = 4.985) is achieved.     

Multi-wall carbon nanotubes coated with polyaniline

Multi-wall carbon nanotubes (CNT) were coated with protonated polyaniline (PANI) in situ during the polymerization of aniline. The content of CNT in the samples was 0-80 wt%. Uniform coating of CNT with PANI was observed with both scanning and transmission electron microscopy. An improvement in the thermal stability of the PANI in the composites was found by thermogravimetric analysis. FTIR and Raman spectra illustrate the presence of PANI in the composites; no interaction between PANI and CNT could be proved. The conductivity of PANI-coated CNT has been compared with the conductivity of the corresponding mixtures of PANI and CNT. At high CNT contents, it is not important if the PANI coating is protonated or not; the conductivity is similar in both cases, and it is determined by the CNT. Polyaniline reduces the contact resistance between the individual nanotubes. A maximum conductivity of 25.4 S cm⁻¹ has been found with PANI-coated CNT containing 70 wt% CNT. The wettability measurements show that CNT coated with protonated PANI are hydrophilic, the water contact angle being ∼40°, even at 60 wt% CNT in the composite. The specific surface area, determined by nitrogen adsorption, ranges from 20 m² g⁻¹ for protonated PANI to 56 m² g⁻¹ for neat CNT. The pore sizes and volumes have been determined by mercury porosimetry. The density measurements indicate that the compressed PANI-coated CNT are more compact compared with compressed mixtures of PANI and CNT. The relaxation and the growth of dimensions of the samples after the release of compression have been noted.     

Effect of Al2O3 particle size on preparation and properties of ZTA ceramics formed by gelcasting

Zirconia-toughened alumina (ZTA) ceramics were prepared using three different kinds of Al₂O₃ powders (marked PW-A average particle size: 7.53 μm, marked PW-B average particle size: 1.76 μm, marked PW-C average particle size: 0.61 μm) by gelcasting. Effect of Al₂O₃ particle size on zeta potential, dispersant dosage and solid volume fractions of ZTA suspensions as well as the mechanical properties of ZTA green bodies and ceramics were investigated. The optimum dosages of dispersant for ZTA suspensions prepared by PW-A, PW-B and PW-C are 0.4 wt%, 0.5 wt% and 0.7 wt%, respectively. The highest solid volume fractions of ZTA suspensions can reach 62 vol% (SP-A), 60 vol% (SP-B) and 52 vol% (SP-C), respectively. The green bodies show a bending strength as high as 20 MPa, which can meet the requirement of machining. The Al₂O₃ powder with fine particle size is beneficial to the improvement of mechanical properties. The ZTA ceramics prepared by PW-B Al₂O₃ powder show the highest bending strength (680 MPa) and toughness (7.49 MPa m^1/2).     

Tubular composite PVA ceramic supported membrane for bio-ethanol production

Thin polyvinyl alcohol (PVA) layers loaded with fumed silica were coated on porous ceramic supports. Scanning electron microscope (SEM) was used to characterize the ceramic-supported thin PVA active layers and the effects of coating gel PVA concentration on thickness and density of the active layers were investigated. Pervaporation (PV) dehydration of 90 wt.% ethanol was performed at temperatures of 30, 45 and 60 °C. The values of water flux (0.05–2.92 kg/m² h) and selectivity (3–180) exceed typical values obtained for pure PVA membranes. Besides the pervaporation separation index (PSI) varies from 5.84 to 82.81. Compared to pure PVA membrane with maximum PSI of 47.2, the pervaporation performance was significantly improved. The best separation performance was obtained using the membrane prepared from 5 wt.% PVA solution containing 6 wt.% fumed silica and at pervaporation temperature of 45 °C with permeation flux of 1.69 kg/m² h, and selectivity of 50. The highest permeation flux, selectivity and PSI was 2.92 kg/m² h, 180 and 82.81, obtained at 60, 30 and 45 °C, respectively, while using membranes loaded with 8, zero and 6 wt.% of fumed silica in PVA membrane prepared from 5, 10 and 5 wt.% PVA solutions, respectively. The novel ceramic support increased mechanical strength of the membrane and protected the ultrathin polymeric top active layer under aggressive operating conditions, especially high pressure gradient across the membrane. Incorporation of fumed silica also resulted in higher water permeation flux. Due to these results, the synthesized membranes are suitable for ethanol purification in industrial scales.     

Mixed matrix membranes of sodium alginate and poly(vinyl alcohol) for pervaporation dehydration of isopropanol at different temperatures

Mixed matrix membranes of sodium alginate (NaAlg) and poly(vinyl alcohol) (PVA) containing 5 and 10 wt.% silicalite-1 particles were fabricated by solution casting method and the cured membranes were crosslinked with glutaraldehyde. These membranes were used in pervaporation (PV) dehydration of isopropanol at 30, 40, 50 and 60 °C. Membrane morphology was studied by scanning electron microscopy and universal testing machine to assess their mechanical strengths. Swelling results of the pristine and mixed matrix membranes were correlated with their PV performances. Selectivities of the mixed matrix membranes of NaAlg were 11,241 and 17,991 with the fluxes of 0.039 and 0.027 kg/m² h, respectively, for 5 and 10 wt.% silicalite-1 loadings. Corresponding values for mixed matrix membranes of PVA were 1295 and 2241, and 0.084 and 0.069 kg/m² h, respectively, for 10 wt.% water-containing feed at 30 °C. Pristine membranes of NaAlg and PVA exhibited lower selectivities of 653 and 77 with increased fluxes of 0.067 and 0.095 kg/m² h, respectively. From the temperature dependence of flux and diffusivity data with 10 wt.% water-containing feed, Arrhenius plots were constructed to compute heat of sorption, ΔH_s values. Mixed matrix membranes of NaAlg were better than PVA mixed matrix membranes at all compositions (10-40 wt.%) of water. Molecular dynamics (MD) simulation was employed to compute the interfacial interaction energies of NaAlg and PVA polymers with silicalite-1 filler; also sorption of liquid molecules was computed. Simulated diffusivities compared well with the experimental data. Thermodynamic treatment of sorption, diffusion and permeation processes was attempted based on the Flory-Huggins theory to explain the PV performances of the membranes.     

Ionene segmented block copolymers containing imidazolium cations: Structure-property relationships as a function of hard segment content

Imidazolium ionene segmented block copolymers were synthesized from 1,1′-(1,4-butanediyl)bis(imidazole) and 1,12-dibromododecane hard segments and 2000 g/mol PTMO dibromide soft segments. The polymeric structures were confirmed using ¹H NMR spectroscopy, and resonances associated with methylene spacers from 1,12-dibromododecane became more apparent as the hard segment content increased. TGA revealed thermal stabilities ≥250 °C for all imidazolium ionene segmented block copolymers. These ionene segmented block copolymers containing imidazolium cations showed evidence of microphase separation when the hard segment was 6-38 wt%. The thermal transitions found by DSC and DMA analysis found that the T_g and T_m of the PTMO segments were comparable to PTMO polymers, namely approximately −80 °C and 22 °C, respectively. In the absence of PTMO soft segments the T_g increased to 27 °C The crystallinity of the PTMO segments was further evidence of microphase separation and was particularly evident at 6, 9 and 20 wt% hard segment, as indicated in X-ray scattering. The periodicity of the microphase separation was well-defined at 20 and 38 wt% hard segment and found to be approximately 10.5 and 13.0 nm, respectively, for these ionenes wherein the PTMO soft segment is 2000 g/mol. Finally, the 38 and 100 wt% hard segment ionenes exhibited scattering from correlations within the hard segment on a length scale of approximately 2-2.3 nm. These new materials present structure on a variety of length scales and thereby provide various routes to controlling mechanical and transport properties.     

Structure and thermal properties of La0.6Sr0.4Co0.2Fe0.8O3−δ-SDC carbonate composite cathodes for intermediate- to low-temperature solid oxide fuel cells

The structure and thermal properties of La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ-SDC carbonate (LSCF-SDC carbonate) composite cathodes were investigated with respect to the calcination temperatures and the weight content of the samarium-doped ceria (SDC) carbonate electrolyte. The composite cathode powder has been prepared from La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ and SDC carbonate powders using the high-energy ball milling technique in air at room temperature. Different powder mixtures at 30 wt%, 40 wt% and 50 wt% of SDC carbonate were calcined at 750-900 °C. The findings indicated that the structure and thermal properties of the composite cathodes were responsive to the calcination temperature and the content of SDC carbonate. The absence of any new phases as confirmed via XRD analysis demonstrated the excellent compatibility between the cathode and electrolyte materials. The particle size of the composite cathode powder was ∼0.3-0.9 μm having a surface area of 4-15 m² g⁻¹. SEM investigation revealed the presence of large particles in the resultant powders resulting from the increased calcination temperature. The composite cathode containing 50 wt% SDC carbonate was found to exhibit the best thermal expansion compatibility with the electrolyte.     

Influence of temperature on pyrolysis of recycled organic matter from municipal solid waste using an activated olivine fluidized bed

Pyrolysis of an organic concentrate from municipal solid waste was carried out using a bench-scale fluidized bed reactor at 350-540 °C comparing Al₂O₃ with activated olivine sand as bed materials. A maximum oil yield of 50 wt.% was obtained using the activated olivine sand at 400 °C while only 45 wt.% was obtained at 500 °C using Al₂O₃. The bio-oils using activated olivine sand at 400 °C had an H/C ratio of 1.50 and O/C ratio of 0.37 and were less aromatic and less nitrogenous compare to the oils obtained using Al₂O₃ at 400 °C where the H/C ratio was 1.32 and the O/C ratio was 0.44. The aromatic compounds were found to be reduced while the aliphatic compounds increased in the oils generated using activated olivine sand. The calorific value of the bio-oil at 500 °C was 29 MJ/kg using activated olivine sand while the bio-oil using Al₂O₃ was 23 MJ/kg. The presence of iron, magnesium and other oxides probably promotes the removal of oxygen, which indicates that the activation energy of C―O bond breakage is reduced compared to the C―C bonds, thus promoting dehydration, decarboxylation and alkalation reactions to produce aliphatic fatty acid at lower temperatures.     

Thermal conductivities from temperature profiles in the polymer electrolyte fuel cell

We report measured temperatures inside the single polymer fuel cell, and thermal conductivities and heat transfer coefficients calculated from these. Temperatures were measured next to the membrane on its two sides, and in the gas channels. Higher temperatures (5 °C or more at 1 A/cm²) were found at the membrane electrode surface than in the gas channels. The thermal conductivity of the membrane (λ^m) was small, as expected from the properties of water and polymer, while the heat transfer coefficient of the electrode surfaces (λ^s) was smaller, 1000±300 W/m² K for a layer thickness of 10 μm. The real coefficient is smaller, since the measured temperatures are systematically smaller than the real ones. The electrode surface heat transfer coefficient is not previously reported. The average value for the catalyst surface plus gas diffusion layer was 0.2 W/m K.