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Non-petroleum route to produce transportation fuels is alternative way to address the fast depletion of the crude oil reservoir, especially in China. In this work, series of nanocrystal H[Fe, Al]ZSM-5 zeolite samples with different SiO 2 /Al 2 O 3 ratio were prepared with hydrothermal method using sodium aluminate and tetraethyl orthosilicate as Al and Si sources, respectively, and the tetrapropylammonium hydroxide was used for structure-directing agent (SDA). The synthesized zeolites were characterized in detail by UV–Vis, X-ray diffraction, scanning electron microscope, N 2 sorption, X-ray fluorescence, ammonia temperature-programmed desorption and pyridine-FTIR techniques. Fe species were incorporated into ZSM-5 framework, resulting in the formation of some new active sites. For the Iron-containing nanocrystal ZSM-5 samples with different SiO 2 /Al 2 O 3 ratio, the B and L acid strength and amounts are determined by the coexistence and synergistic effect of Al- and Fe-based acid sites. The catalytic results illustrated that the H[Fe, Al]ZSM-5 zeolite with SiO 2 /Al 2 O 3 ratio for 45 exhibited the best catalytic activity and stability due to its maximum B acid amount and higher B/L ratio. The DME conversion remains at >98% within the 135 h investigation. Moreover, the gasoline yield was up to 72.5%, and the selectivity for aromatics and durene could be reduced to 40% and 1%, respectively. Nanocrystal H[Fe, Al]ZSM-5 zeolites with different SiO 2 /Al 2 O 3 ratio were synthesized by hydrothermal method. Dimethyl ether to gasoline (DTG) reaction was chosen to test the catalytic performance of as-prepared nanocrystal H[Fe, Al]ZSM-5 zeolites, indicating that the nanocrystal H[Fe, Al]ZSM-5 catalysts exhibited the outstanding catalytic performance in DTG process. Unlabelled Image • Nanocrystal H[Fe,Al]ZSM-5 zeolites of various SiO 2 /Al 2 O 3 ratio were synthesized. • The effect of SiO 2 /Al 2 O 3 ratio on DME to gasoline was systematically studied. • Zeolite acidity is related with the synergistic effect of Al- and Fe-based acid sites. • Catalyst with SiO 2 /Al 2 O 3 ratio of 45 exhibited the best catalytic performance for DTG reaction. [ABSTRACT FROM AUTHOR]

In this study, the comparison of the pellets produced from untreated EFB, the hydrothermally treated empty fruit bunch (HTT-EFB) and washed HTT-EFB was performed. The pelletization of the raw EFB, HTT-EFB, and washed HTT-EFB was conducted using a single pellet making device. In experiments performed at room temperature under a densification pressure of 150 MPa, the physical properties, mechanical strength, durability, and hydrophobicity of the produced pellets were then evaluated. Scanning electron microscope (SEM) analysis was also performed to investigate the binding mechanisms within the pellets. The results showed that the washed HTT-EFB pellets had higher mechanical strength and durability than the HTT-EFB or raw EFB pellets. The HTT-EFB pellets also demonstrated hydrophobic behavior against moisture exposure. However, the washed HTT-EFB pellets required higher compaction energy than the other pellets. From this analysis, it was determined that the changes in the composition of EFB biomass owing to HTT and the washing process regulate pelletization behavior and affect the binding mechanism during pelletization. In addition, the combustion performance of treated EFB samples showed significant improvements as it has higher ignition temperatures with more uniform combustion profiles as shown in the data obtained from TGA analyser. This research demonstrated that the combination of HTT, washing, and pelletization cotreatment is a promising method for upgrading EFB into energy-dense, durable, and homogeneous hydrophobic solid fuel. [ABSTRACT FROM AUTHOR]

Biodiesel productions from Mahua oil using two different catalysts, including KOH and activated red mud by catalytic cracking (waste from aluminum industry) were compared in distinctive blends of diesel fuel. Red mud was subjected to characterization studies to find the mechanism of red mud during catalytic cracking using Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM). The cracking process was carried at 300 °C for 2 h and different blends of biodiesel (B25, B50, B75, and B100) were examined for physical properties. Furthermore, the different blends were subjected to a four-stroke diesel engine to study its engine performance. The results showed that the changes in elemental composition during EDS analysis could be an important reason for red mud to have a better calorific value (10,601 kcal/kg) compared to KOH as a catalyst. The NO x emission from KOH biodiesel was 7.5% higher compared to red mud biodiesel when it was blended 100% at 1500 RPM at a maximum brake power (5.2 kW). From the findings of this study, it was evident that using red mud as a catalyst not just increases most of the properties of the fuel, but also reduces the stress on the environment in the form of less emission and fuel consumption. Since red mud was a hazardous waste from aluminum industry, utilizing it for biodiesel productions could also be an economically viable option. [ABSTRACT FROM AUTHOR]

This work focused on the transformation of inorganics in Miscanthus ash and the interaction of ashes with silica sand, olivine and calcined olivine. The samples were heat-treated in a laboratory furnace without the fluidization of the bed particles. The transformation of Miscanthus ash was studied with experimental methods (chemical fractionation analysis, ICP-MS, XRD, SEM-EDX) and with thermodynamic calculations (FactSage) between 400 °C and 1400 °C. The ash-bed material interface was analyzed by scanning electron microscope (SEM-EDX). The effect of the harvest time and the atmosphere were investigated. The characterization of the ashes (winter harvest) revealed the presence of alkali salts, carbonates and silica at low temperature and the formation of Ca and Mg-silicates, Ca-phosphate and molten K-silicate above 750 °C. In oxidizing atmosphere the S formed K 2 SO 4 , while in reducing atmosphere the S left in the gaseous phase. The ash of the summer harvest Miscanthus contains more K and less Ca and Si, therefore carbonates and salts are formed both at low and high temperature. The interaction tests revealed only physical adhesion between the molten ash and the silica sand, while the olivine played an active role in the agglomerate formation via the diffusion of Fe into the molten ash. [ABSTRACT FROM AUTHOR]

This paper investigates the potential use of ultrasonic treatment in comminution of coal in water media. A laboratory type, high intensity ultrasonic generator (750 W, 20 kHz) equipped with a horn transducer system and a titanium alloy horn tip (13 mm in diameter) was used as a source of ultrasonic treatment. The tests were performed at different levels of variables including ultrasonic power level (9.5–113.6 W/cm 2 ), ultrasonic treatment times (5–20 min) and solid ratio of pulp (5–20% w/w). Temperatures of pulp atmosphere during ultrasonic treatment at different solid ratios and ultrasonic power levels were recorded. Particle size distribution curves were used to determine the degree of comminution. It was observed that ultrasonic treatment improved size reduction of coal significantly. Higher ultrasonic power levels and treatment times provided coal particles to be reduced to finer sizes. In addition, scanning electron microscope (SEM) and stereo microscope examinations were carried out to support test results. Selective comminuting ability of ultrasonic treatment was revealed from pyritic sulfur analysis for different size fractions of treated coal. [ABSTRACT FROM AUTHOR]

The flow behavior of high-temperature ash (HTA) and low-temperature ash (LTA) from room temperature to 1350 °C was studied. The change of volume in the heating process was investigated by the heating stage microscope. The mineral matter composition and microstructure characteristics of HTA and LTA samples during the heating process were observed by X-ray diffraction and scanning electron microscope. The HTA and LTA samples shrink at the first heating stage, and then melt. With the increasing temperature, the minerals in HTA and LTA samples change and the flowability improves. The HTA and LTA samples show significantly spreading property. However, the shrinkage of HTA sample is different from that of LTA sample. The volume change of HTA sample is not obvious when the temperature is lower than 800 °C, while the volume of LTA sample presents the continuous decrease. At the temperature range of 800–1000 °C, the main minerals formed in LTA and HTA samples are augite and albite, respectively. Those mineral matter variations result in the obvious volume change of HTA and LTA samples. In addition, the microstructure of the samples shows that the shapes of particles in LTA are irregular and the surface of particles is coarse at lower temperature. With the increasing temperature, the attachments on the particle surface agglomerate, melt and accumulate. The variation of particles validates the change of flow behavior in the heating process. [ABSTRACT FROM AUTHOR]

Abstract: Activation of grape seed char upon successive cycles of liquid phase oxidation followed by high temperature desorption permits a tailored development of porosity. In this work three different oxidants (HNO3, H2O2, and (NH4)2S2O8), have been tested and the desorption temperature has been varied within 850–950°C upon 10 activation cycles. A high increase of BET surface area was observed in the first five cycles with HNO3 as oxidizing agent giving rise to values higher than 1200m2 g−1 at around 50% burn-off. Activation with H2O2 and (NH4)2S2O8 led to a significantly lower development of surface area, with 600 and 800m2 g−1 respectively at that burn-off. The analysis of the pore size distribution showed that porosity was generated through the creation of new micropores and widening of existing ones upon activation with HNO3 and (NH4)2S2O8, whereas H2O2 mostly led to the widening of the narrow micropores already existing in the starting char. The activated carbons obtained are essentially microporous, with some small contribution of mesoporosity in the HNO3 series (Vmicro =0.69cm3 g−1; Vmeso =0.07cm3 g−1). SEM images showed that the activated carbons maintained the granular morphology of the seeds after 10cycles showing a hollow core structure with a wall thickness of about 200μm. [Copyright &y& Elsevier]

Abstract: Coke samples from tuyere level of a blast furnace were obtained through tuyere drilling. Mineral matter of tuyere level cokes was quantified using SIROQUANT and examined using scanning electron microscope. The apparent CO2 reaction rates were measured using a fixed bed reactor. About 50% of the total inorganic matter of tuyere cokes was found to occur as amorphous or glassy phase. At most of the tuyere level locations, Quartz and mullite contents of the feed coke decreased significantly or disappeared. Silicon carbide and gupeiite were found to be the most notable and common silicon and iron bearing minerals of cokes particularly in the raceway region while gehlenite and spinel were the typical calcium and magnesium bearing minerals respectively. Tuyere level cokes also indicated the presence of significantly high potassium levels as well as the graphite formation. The apparent reaction rate of tuyere level cokes is shown to increase up to ten times of the feed coke reaction rate, and is strongly related to the total amount of potassium species. The study highlights the strong influence of the raceway temperature, the alkali loading and the hot metal presence on the modification of the mineralogy and reactivity of tuyere level cokes with implications on coke selection criterion. [Copyright &y& Elsevier]

The content of low-melting alkali metals in biomass is relatively high, resulting in alkali metal vapor in the gasification gas. In the biomass gasification integrate with solid oxide fuel cell system, the alkali metals will enrich on anode in long term operation, which will affect the discharge performance. In this work, multiple loads by the aqueous solution are used to simulate the enrichment process of potassium carbonate on the NiO/YSZ anode surface. The results show that a light potassium carbonate load can improve the peak power density of the solid oxide fuel cell. But the peak power density of the cell gradually decreases with the load time increasing higher than twice. Through electrochemical impedance spectroscopy, it is found that the second potassium carbonate loads reduced the polarization impedance from 0.69 Ω·cm2 to 0.45 Ω·cm2. But no obvious change of ohmic resistance is observed, indicating potassium carbonate loads affect anode catalytic reaction. Through scanning electron microscopes and X-ray diffractometer characterization, it can be concluded that a light potassium carbonate load can reduce the grain size of nickel and improve the anode three-phase boundaries, which leads to the improvement of cell peak power density. [Display omitted] • The enrichment process of alkali metals salt in biomass gas on SOFC is studied. • The peak power density improves 23.03% after second K 2 CO 3 load. • Nickel grain size of anode evolves with the number of K 2 CO 3 loads. [ABSTRACT FROM AUTHOR]

Abstract: In order to control the ash deposition, a surface treatment of the tubes, using a thermal spraying technique, was proposed in this study. First, adhesion forces between ash pellets and several alloy specimens were measured, using a tensile testing machine, to evaluate validity of this technique for a long period. The result shows that a Ni alloy as the thermal spraying material could reduce the adhesion force. Second, the reduction mechanisms of ash deposition were elucidated, observing the interfaces between the ash pellets and the alloy specimens by a scanning election microscope with energy dispersive spectroscopy. As a result, diffusion of Fe compounds in the tube could be depressed by the Ni alloy coated on the tube surface. Finally, field tests of this technique were also carried out in some practical multi-fuels fired boilers, so that this technique showed a good performance, especially for clinker. [Copyright &y& Elsevier]

Abstract: The declining reserves and fluctuating prices of fossil fuels led to intensive search for an alternative to replace or complement petroleum derivates as main fuel resource. In this context biomass appears as an attractive feedstock, because of that a comprehensive characterization is needed, focusing morphological study, using scanning electron microscope (SEM) and particle size distribution, composition with X-ray dispersive energy (EDX), thermal analyses, using thermogravimetry and combustion gas analysis, to select the best behavior as a fuel from six biomass samples (almond shell, rice husk, straw, vegetable coal, wine pomace and a randomly chosen commercial brand of wood pellets) trying to comb all the range of commercial fuels most commonly available in the Spanish solid biofuel market. [Copyright &y& Elsevier]

Abstract: The main purpose of the present work was to quantify and characterize morphologically and chemically the emissions of particulate matter (PM) from a domestic pellet-fired boiler during steady-state operation for different boiler thermal inputs. The PM quantification was made with the aid of a low pressure three-stage cascade impactor and the PM characterization using SEM/EDS analysis (scanning electron microscope/energy dispersive X-ray spectrometry). The measured PM emissions varied between ≈160mg/Nm3@13% O2 and ≈490mg/Nm3@13% O2, being the emissions mainly dominated by particles with sizes below 2.5μm and above 10μm regardless of the thermal input. The SEM analyses revealed the presence of ultra fine (<100nm) particles, sub-micrometer and micrometer sized particles/agglomerates, and isolated spherical and irregularly shaped large particles for all boiler operating conditions examined. The ultra fine particles, formed after the soot formation process, were composed mainly of O, K, Cl, Na and S; the sub-micrometer (and micrometer) sized particles/agglomerates, formed from soot, contained mainly carbon, oxygen, Ca, Mg, K and P; and the isolated spherical and irregularly shaped large particles, released from the fuel bed during combustion, consisted mostly of carbon and oxygen with minor amounts of Ca and Mg. [Copyright &y& Elsevier]

Abstract: For an oxy-fuel circulating fluidized bed combustion system, the limestone calcination is normally prevented due to excessive CO2 partial pressures and the limestone is subject to a direct sulfation reaction. The enhancement of the direct sulfation of limestone by Na2CO3 was investigated under high CO2 partial pressure in a thermogravimetric apparatus (TGA) and scanning electron microscope (SEM) analysis method. A commercial limestone with a mean size of 18.8 μm was used. Experimental results indicate that the incorporation of Na+ ions in solid product CaSO4 lattice structures results in formation of more extrinsic point defects in the crystal lattices of CaSO4 and a significantly increased solid-state diffusivity/mobility in the solid product. So the direct sulfation of Na2CO3-doped limestone shows higher rate and higher degree of conversion in the later stage of sulfation, in comparison with the direct sulfation of original limestone. The reaction changes from diffusional control to chemical reaction control in the presence of Na2CO3 because of the effect of foreign ions on accelerating the solid-state diffusion. [Copyright &y& Elsevier]

Abstract: The size distribution, microstructure, and chemical composition of particulate matter samples from coal-fired power plants in China were measured using a laser particle analyzer, a scanning electron microscope (SEM), and an inductively coupled plasma-atomic emission spectrometer (ICP-AES). The size distribution showed differences between the electrostatic precipitator capture efficiencies for coarse and fine particles. The microstructure measurements showed three typical particulate microstructures, spherical particles, plerospheres, and irregular particles. The surfaces of most spherical particles had microspheres that were often agglomerated together. The chemical composition of the particulate matter changed as the size decreased, while had differences from different feed coal. [Copyright &y& Elsevier]

Ten samples originating from different boiler FBC systems burning petroleum coke and one laboratory sample were chosen to perform a study on the development, structure, and composition of deposits formed by agglomeration in various locations. The work focused on examination by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. The possibility of a contribution of liquid phases in the adherence to solid surfaces and in agglomeration was discussed and checks by SEM, EDX, and analysis by neutron activation were performed; no evidence could be found either for liquid phases or for any role of vanadium or alkaline element compounds. The agglomerations result from the continued sintering of CaSO4 particles until they build up a strong framework that is indefinitely extended, into which particles of different and complex compositions are bound, without contributing to the cohesion. Chemical sintering occurring by the sulphation of CaO into CaSO4 appears to be an important contribution while CaO is still available, but sintering also occurs by mass transfer mechanisms and continues after the depletion of CaO. Deposits formed in regions only reached by fly ash (convection section), and also in in-bed deposits, grow from particles <50 μm, mostly in the range of 10 μm or less. In regions collecting bed ash (e.g., J-valves), the deposit grows from the sintering together of particles on the order of 100–300 μm (originally bed ash particles), which themselves appear as conglomerates of extensively sintered smaller particles. [Copyright &y& Elsevier]

This study aims to directly analyze untreated process samples from a full-scale BGL gasifier. It assesses as well as categorizes the findings to identify the most important effects governing the behavior of slags under gasifier conditions. A process slag sample from the Schwarze Pumpe BGL-type waste gasifier is thoroughly analyzed via X-ray diffraction (XRD), X-ray fluorescence (XRF), and using a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). The results are interpreted with the aid of thermodynamic equilibrium calculations using the FactSage™ software package to yield the main influence factors on slag viscosity and -structure. Since these are derived from full scale process samples, the severity of the impact to these processes can be assessed. Especially the effect of secondary phases apart from the main slag phase is evaluated. The differences between laboratory measurements and full-scale processes are identified. The composition of the gas atmosphere above the slag bath cannot easily be determined. This study uses a method to determine and include this gas atmosphere into the process slag analysis through thermodynamic equilibrium calculations. The temperature of the slag bath and the gas atmosphere around the slag is backtracked via analytically validated thermodynamic equilibrium calculations. • Unmolten silica particles found in full scale BGL slag. • Descriptive thermodynamic equilibrium model yields valuable information about slag. • Sulfur and chlorine should be regarded when analyzing BGL slag. • Analysis of metal phase in slag showed that temperature of the slag bath was between 1180 and 1330 °C. • Oxygen partial pressure affecting BGL slag was determined to be between 10−15 and 10−13 bar. [ABSTRACT FROM AUTHOR]

We report the synthesis of biochar-CNT-NiO composite and its application as anode material in lithium-ion batteries (LIBs). The scanning electron microscope (SEM) analysis results displayed that the NiO particles were exposed on the surface of CNTs. HRTEM results showed a more uniform distribution of NiO particles on the biochar-CNT-NiO compared to that of biochar-NiO. The electrochemical performance of the biochar-CNT-NiO indicated that composite nanostructure was able to deliver an excellent reversible capacity for LIB. The capacity of biochar-CNT-NiO (674.6 mAh/g) was significantly higher than biochar-NiO without CNTs (368.4 mAh/g) and Char-CNT-Ni (140.9 mAh/g) after 100 cycles. The biochar-CNT-NiO composite exhibited a remarkable discharge rate performance. This outstanding performance was caused by the presence of CNTs on the biochar-CNT-NiO, which mitigates the volume change of NiO during cycles and speeded up electron transfer. • The Char-CNT-NiO composites exhibited excellent electrochemical performances during lithium-ion battery tests. • CNTs in the composites mitigated the volume expansion and facile ion diffusion path. • The Char-CNT-NiO composites maintained a high reversible specific capacity. [ABSTRACT FROM AUTHOR]

The current study focused on the particulate matter emissions of polyoxymethylene dimethyl ethers (PODE)/diesel blends with PODE blending ratios of 0, 10%, 20% and 30% have been experimentally investigated in a common-rail engine. The influences of PODE blending ratio on the smoke emission, particle size distribution and particle oxidation characteristic are discussed. Results show that the addition of PODE in diesel fuel can effectively reduce smoke emission and its decreasing range becomes larger with increasing PODE blending ratio. With the increment in PODE blending ratio, the particle concentration distribution moves towards the direction of small particle size, and the total particle number concentrations decrease. Besides, the peak values of particle number concentration, surface area concentration, and volume concentration are all decreased. Adding PODE in diesel fuel increases the soluble organic fraction (SOF) content of particles, rises maximum weight loss rate of particles, and lower the peak temperature of particles. Also, the activation energy of pyrolysis reaction of particles decreases, which indicates that the oxidation of particles becomes easier as PODE blending ratio increases. The apparent morphology of particles was measured by scanning electron microscope, and the results show that the morphology of particles sample are mostly chain like or flocculent. Unlabelled Image • PODE/diesel blends can effectively reduce smoke emission, especially at high load. • The addition of PODE will decrease diesel particle size and total particle number. • PODE/diesel blends reduce particle surface area and particle volume concentrations. • PODE/diesel blends increase SOF content and decrease activation energy of particles. [ABSTRACT FROM AUTHOR]

Thermogravimetric analysis (TGA) has been widely used to obtain inherent combustion reactivity data for biomass fuels. However, fundamental information relating such data to systems that operate under conditions closer to those encountered in pulverized fuel (PF) combustion is relatively scarce. This study therefore, compares the combustion reactivity of sawdust devolatilized under slow heating conditions by TGA and fast heating conditions in a drop tube furnace (DTF) representative of PF combustion. The implications of devolatilization temperature, heating rate and residence time were considered. It was established that the char burnout profiles of the DTF char prepared at 1300 °C and 600 ms was similar to the 700 °C TGA char although, the DTF char showed a lower maximum rate. Scanning electron microscope (SEM) images revealed that the TGA chars retained a cell matrix structure with visible macropore network. In contrast, the DTF chars displayed swollen surfaces with distributed pore networks, resulting in higher BET surface areas. The activation energy of the DTF chars was smaller than those of TGA char, demonstrating the presence of greater internal diffusion control. Finally, it is demonstrated for the first time that the compensation effect for biomass char is considerably less than that reported previously for coal chars. • For the first time the combustion reactivity of TGA devolatilized chars was compared to DTF devolatilized chars. • Burnout profile of TGA char devolatilized at 700 °C, 150 °C min−1 correlated with DTF char at 1300 °C, 600 ms. • However, the maximum burning rate of the DTF char was smaller. • Compensation effect for biomass char was found to be considerably less than coal chars. [ABSTRACT FROM AUTHOR]