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For the purpose of researching the rules of combustion heat release, ammonium phosphate dry powder extinguishing agent and water-based fire extinguishing agent were utilized before and after the class A fire common wood stack ignition fuel and class B fire anhydrous ethanol ignition fuel fire extinguishing. For wood stack fire, 0.5A wood stack was used for blank combustion test, and the pan fire ignition method for the same type and scale of wood stack fire extinguishing experiment. For absolute ethanol fire, fire suppression was studied using a 13B scale. The change characteristics of the combustion field before and after action of the dry powder extinguishing agent and water system extinguishing agent were measured by thermocouple, heat flow meter and digital camera. The findings of the experiment demonstrated that in the combustion experiment of wood stack, the temperature of 0.5A wood stack of the blank group could reach 800 °C, and the temperature reduction rate of free combustion was 2.62 °C/s. It took an average of 36.5s and 2.25 kg of ammonium phosphate dry powder to put out the fire，and the temperature reduction rate was 4.18 °C/s. The average amount of water-based extinguishing agent used to extinguish a fire was 1.21 kg, yet the average time to do so was just 12.5 s, and the average rate of temperature drop was 10.14 °C/s. In the experiment where an ethanol pool fire was being burned, the typical amount of water-based fire extinguishing chemical used was 3.44 kg, and the typical extinguishing time was 18 s, the maximum temperature drop rate could reach 35.6 °C/s in the initial stage of fire extinguishing, despite the fact that the dry powder fire extinguisher containing ammonium phosphate was used, the fire was not properly controlled.

Three types of α-Mn2O3 catalysts with different well-defined morphologies (cubic, truncated octahedra and octahedra) and exposed crystal facets have been successfully prepared via hydrothermal processes, and evaluated for ethanol total oxidation with low ethanol concentration at low temperatures. The α-Mn2O3-cubic catalyst shows a superior catalytic reaction rate than that of α-Mn2O3-truncated octahedra and α-Mn2O3-octahedra under high space velocity of 192,000 mL/(g·h). Based on the characterization results obtained from XRD, BET, FE-SEM, HR-TEM, FT-IR, H2-TPR, XPS, ethanol-TPD, and CO-TPSR techniques, the observed morphology-dependent reactivity of α-Mn2O3 catalysts can be correlated to the good low-temperature reducibility, abundant surface Mn4+ and adsorbed reactive oxygen species, which was originated from the exposed (001) crystal planes. Through tuning the morphology and exposed (001) crystal facet of α-Mn2O3, a highly active ethanol oxidation catalyst with high selectivity and excellent stability is obtained. The developed approach may be applied broadly to the development of the design principles for high-performance low-cost and environmentally friendly Mn-based oxidation catalysts. [ABSTRACT FROM AUTHOR]

Ethanol is one of the most promising renewable fuels for decarbonizing off-road and heavy-duty engine applications due to a well-established industry with high production capacity, existing distribution infrastructure, low carbon intensity and reasonable cost. However, several properties, such as ignitability, energy density and lubricity, are not suitable for mixing-controlled combustion in modern compression-ignition (CI) engines as those used in most off-road and heavy-duty applications, with ignitability being the main technical barrier for ethanol compression-ignition. In this work, ethanol MCCI is enabled by doping ethanol with 2-ethylhexyl nitrate (EHN), an inexpensive cetane improver typically used with diesel fuel. A medium-duty single-cylinder research engine is operated at low- and part-loads with boundary conditions representative of diesel engine operation. Production engine geometry was used to test drop-in potential of the fuel. Three EHN levels are tested, 3 % vol , 5 % vol and 7 % vol. The experiments demonstrated successful MCCI combustion of ethanol within acceptable combustion control range, constrained by the transition to kinetically-controlled combustion for highly advanced injection timings and high cycle-by-cycle variability of the pilot injections for the most retarded injection timings. Results show that the combustion control range increases as the EHN content increases due to the higher fuel reactivity. Under the part-load, ethanol combustion shows higher thermal efficiency than that of diesel due to lower heat transfer loss. At low load, ethanol combustion is only achievable with 7 % vol EHN and leads to lower thermal efficiency than diesel mainly due to inefficient combustion. The impact of increasing the compression ratio was also investigated, resulting in stable ethanol combustion at low load with 3 % vol EHN. Particulate matter emissions of ethanol are much lower than the current US off-road limit and the 2027 US EPA HD limit, with NO x emissions within the range of those of diesel. Finally, analysis of exhaust gas emissions shows that unburned hydrocarbons of ethanol combustion are composed mainly by ethanol, ethene and acetaldehyde. • Ethanol mixing-controlled compression ignition (MCCI) combustion is achieved. • Multiple injection strategy is introduced for stable operation with ethanol. • The effect of an ignition enhancer (EHN) on ethanol combustion is investigated. • Ethanol improved heat transfer loss and particulate matter emissions. • High compression ratio allowed stable operation with less ignition enhancer. [ABSTRACT FROM AUTHOR]

This paper presents the results of two-line OH planar laser-induced fluorescence (PLIF) thermometry in a laminar conical flame of a gas–droplet mixture of ethanol and air. Laminar flow of a droplet-laden ethanol–air uniform mixture was produced by an ultrasonic atomizer in a vessel filled with liquid ethanol. The properties of the two-phase flow at the nozzle exit without combustion were controlled by a time-shift optical sensor. The temperature field was estimated based on the excitation of the (5) and (14) lines of the (1–0) band of the – electronic system. The spatial nonuniformity of the energy distribution in the laser light sheet illuminating the central plane of the flame cone and the change in the pulse energy from frame to frame were compensated using an additional camera recording the laser light intensity distribution in the calibration cuvette. [ABSTRACT FROM AUTHOR]

Bioethanol as the renewable biomass fuel gradually becomes a promising feedstock for hydrogen production. To improve the efficiency of hydrogen production, a typical double-layer porous media burner was established for the partial oxidation reaction of ethanol (POE). The effects of porous media structure, initial ethanol and air conditions on the temperature distribution and gas production were investigated based on the start-up characteristics of the burner. The results indicate that the lowest start-up time (2400 s) and best hydrogen production (9.80%) were obtained by filling the downstream section with 8 mm Al 2 O 3 pellets and introducing ethanol at the upstream inlet, compared with that of 6 and 10 mm pellets. The productions of methane and hydrogen were improved to some extent by adding the water with 10% fraction. And the highest concentration of hydrogen was achieved at the air velocity of 8 cm/s. When the O 2 /C ratios were 0.2 and 0.25, the maximum hydrogen yield (23.28%) and ethanol conversion (77.42%) were obtained respectively. • Porous media burner was designed to introduce the liquid ethanol for hydrogen production. • Hydrogen production was promoted with the addition of 10% water. • Maximum hydrogen yield of 23.28% was obtained at the O 2 /C ratio of 0.20. [ABSTRACT FROM AUTHOR]

This paper deals with the study of the reducibility of Ni−Fe spinel oxides prepared by co‐precipitation and hydrothermal methods with NaOH or ammonia and their behavior in ethanol combustion. The reducibility was investigated by X‐ray photoelectron spectroscopy (XPS) after pretreatment under H2 at 400 °C. Depending on the synthesis method, structural properties (X‐ray powder diffraction (XRD) and Raman analysis), the surface area (BET), particle size (Rietveld refinement), as well as the surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied. The best performances were obtained for hydrothermal conditions with a total conversion achieved at ∼ 300 °C. Ni2+ species seem to play a significant role in complete oxidation of ethanol; they were identified as the active species. A good correlation between structural, textural, reducibility and catalytic activity was established. [ABSTRACT FROM AUTHOR]

Highlights • H 2 is autothermally generated from ethanol in a parallel-plates reactor. • Adequate thermal coupling between combustion and reforming of ethanol is predicted. • Feasible integration between the reactor and heat exchangers is proved. • Splitting the fuel feed reduces hot spots while enables extra H 2 yields. • Importance of proper heat loss quantification is evidenced. Abstract This paper deals with the study of the integration of ethanol steam reforming and ethanol combustion in a parallel plates reactor aiming a hydrogen production of 1 kW th equivalent. The study was performed by means of a mathematical model of a non-adiabatic reactor and the associated heat exchangers used for preheating purposes. Focus is given here to the influence of the insulation of the reactor and heat exchangers, the fuel concentration, fuel distribution policy to the reactor, and reforming flowrate. Thermal coupling between combustion and reforming of ethanol in terms of energetic integration is feasible and an adequate behavior of the reactor and the heat exchangers is predicted. The importance of heat losses to the environment is evidenced since they represent about 35–50% of the heat released by the combustion. Ranges of ethanol fuel concentration (0.6–2.0% of ethanol fuel) and distribution (1 or 2 feed ports), and ethanol reforming load (0.37–0.63 kg/h) were studied to find windows for these variables where a satisfactory operation is possible. [ABSTRACT FROM AUTHOR]

New multipurpose skeletal and reduced chemical-kinetic mechanisms for ethanol combustion are developed, along the same philosophical lines followed in our previous work on methanol. The resulting skeletal mechanism contains 66 reactions, only 19 of which are reversible, among 31 species, and the associated reduced mechanism contains 14 overall reactions among 16 species, obtained from the skeletal mechanism by placing CH 3 CHOH, CH 2 CH 2 OH, CH 3 CO, CH 2 CHO, CH 2 CO, C 2 H3, C 2 H 5 , C 2 H 6 , S − CH 2 , T − CH 2 , CH 4 , CH 2 OH, CH 3 O, HCO, and O in steady state. For the reduced mechanism, the steady-state relations and rate expressions are arranged so that computations can be made sequentially without iteration. Comparison with experimental results for autoignition, laminar burning velocities, and counterflow flame structure and extinction, including comparisons with the 268-step, 54-species detailed San Diego Mechanism and five other mechanisms in the literature, support the utility of the skeletal and reduced mechanisms, showing, for example, that, in comparison with the San Diego mechanism, they reduced the computational time by a factor of 4 (71 % faster) and 12 (93 % faster), respectively. Measures of computation times and of extents of departures from experimental values are defined and employed in evaluating results. Besides contributing to improvements in understanding of the mechanisms, the derived simplifications may prove useful in a variety of computational studies. [ABSTRACT FROM AUTHOR]

Cobalt and mixed iron-cobalt spinel oxides Co x Fe (3-x) O 4 supported on SiO 2 ‘IMP-Co x -500′ and their bulk analogues ‘CP-Co x -500′ were prepared via impregnation and co-precipitation methods respectively and calcined at 500 °C. Thermogravimetric analysis ‘ATG/DTG’, X-ray Diffraction method ‘XRD’, Texture measurements ‘BET/BJH’ and Temperature Programmed Reduction technique ‘TPR’ were used for their characterization. Their catalytic behavior in ethanol combustion was investigated. Results showed that nanostructured oxide materials with spinel structure were obtained with a good dispersion of the active phase at the surface of silica in the case of IMP-Co x -500 compounds. The reduction behavior of the prepared samples is highly dependent on the oxide composition and interaction with the support; which is directly related to the catalytic behavior. The use of supported catalysts improves the catalytic performance and leads the reaction towards a total oxidation by decreasing greatly the formation of partial oxidation products. The obtained values of activation energies are relatively low in comparison with the literature data. A compensation effect was found by carrying out ethanol combustion through the spinel systems considered in this work. [ABSTRACT FROM AUTHOR]

The steam reforming of ethanol is carried out in a microreactor for hydrogen production. The heat for the endothermic reactions is supplied by means of ethanol combustion in air, which is carried out in contiguous microchannels. The same Pd-based catalyst is assumed to be coated on both reforming and combustion channels. By means of a 1D heterogeneous mathematical model, the influence of the feed temperatures of both streams on the reactor performance is analyzed. The results show that the degree of preheating of both streams has a strong influence on the hydrogen yields and maximum temperatures. The effect of the flowrate and composition of the fuel stream on the hydrogen yields is also studied. Fairly high hydrogen yields were obtained ( 2.6 < η H 2 < 3.4 ) with low methane slips, within a feasible range of temperatures for the Pd catalyst (700 < T MAX < 770 °C) to avoid catalyst deactivation. These maximum temperatures could still be further reduced by means of an optimal selection of the air flowrate and ethanol molar fraction on the fuel side, or using distributed feed of fuel along the reactor length. [ABSTRACT FROM AUTHOR]

In this work we present the hot surface ignition of turbulent diffusion oxygen–ethanol hydrothermal flames. For this purpose up to 520 W electric are dissipated through a heating wire. The mean wire temperature and the electrical energy it releases at ignition are reported by measuring the voltage drop across its resistance. The wire temperatures – up to 385 °C – are compared to the auto-ignition temperatures reported in literature and the ignition map of our system is drawn. In case the reactants are injected at room temperature, the hot surface enables ignition for ethanol contents in the aqueous fuel stream above 30 wt.%. In the end, potential applications of the ignition system in the scope of supercritical water oxidation and hydrothermal spallation drilling are highlighted. [ABSTRACT FROM AUTHOR]

Two series of ceria-promoted carbon-supported platinum catalysts have been prepared and evaluated in total oxidation of ethanol, as a model volatile organic compound (VOC), in order to study the effect of the metal precursor (H 2 PtCl 6 or Pt(NH 3 ) 4 (NO 3 ) 2 ) on their physico-chemical properties and catalytic behavior. Catalysts with Pt loading of 1 wt.% and ceria loading of 5, 10 and 20 wt.% have been prepared by the impregnation method, and characterized by several techniques (N 2 adsorption at 77 K, ICP, XRD, H 2 -TPR and XPS). Toluene hydrogenation has been used to obtain an estimation of the platinum dispersion on the investigated catalysts. On the other hand, their catalytic behavior has been evaluated in the total oxidation of ethanol, selected as a VOCs probe molecule. A much higher catalytic activity and selectivity to CO 2 was achieved with chlorinated catalysts. This behavior has been correlated with a high platinum dispersion and a strong metal–CeO 2 interaction in these catalysts which promotes their redox properties. [ABSTRACT FROM AUTHOR]

Herein, cesium was introduced into two kinds of rod-shaped α-MnO 2 with different crystal facets by ion exchange technique, and the as-prepared four catalysts were used to evaluate their performance in the total combustion of ethanol with low concentration. When compared to undoped α-MnO 2 (211) and α-MnO 2 (310) catalysts, the Cs-doped α-MnO 2 (211)-Cs and α-MnO 2 (310)-Cs catalysts showed significantly improved catalytic performance at a high space velocity (SV) (132,000 mL/(g·h)). Kinetic results demonstrate that in catalysts the activation energy (Ea) with Cs dopant is lower than without. The characterization results by various techniques such as XRD, ICP-OES, BET, FE-SEM, HR-TEM, H 2 -TPR, NH 3 -TPD, XPS, and ethanol-TPD reveal that the introduction of Cs into α-MnO 2 samples not only improves the low temperature reducibility but also contributes to the generation of more surface Mn4+ and oxygen vacancies, which are efficient in forming more reactive oxygen species, therefore, boosting ethanol oxidation activity. The incorporation of the alkali cation Cs+ into the α-MnO 2 is an effective strategy in designing low-cost, high-performance, and environmentally friendly metal oxide combustion catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

Low exhaust temperature in homogeneous charge compression ignition (HCCI) significantly limits efficiency of an exhaust aftertreatment system to mitigate high HC and CO emissions in HCCI engines. This article aims to understand the effect of varying input parameters on HCCI exhaust gas temperature (T exh) for an ethanol fuelled engine. A single cylinder engine is used to collect experimental data at 100 different HCCI conditions. The results indicate that variation in combustion parameters such as start of combustion (SOC), burn duration (BD) and maximum in-cylinder pressure (P max) are not effectively correlated with variations of Texh, but the indicated mean effective pressure (IMEP) and constant-volume adiabatic flame temperature (T ad) are strongly related to T exh. These experimental findings were then used to design an artificial neural network (ANN) model to predict T exh. The model was validated with the experimental data, indicating an average error less than 4.5°C between predicted and measured T exh. [ABSTRACT FROM AUTHOR]

Abstract: Adding compounds rich in hydrogen to liquid fuels has the potential to change combustion behavior and enhance performance. One potential additive is ammonia borane (AB), which contains 19.6wt.% hydrogen and can be dissolved in anhydrous ethanol (up to 6.5wt.%). The particular system studied here would have limited use due to energy density and stability but is studied as a model system. Single droplet combustion experiments were performed with AB concentrations in ethanol varying from 0 to 6wt.%. Measurements performed using high speed (5kHz) planar laser-induced fluorescence (PLIF) indicate that hydrogen gas addition from the decomposition of AB continues throughout the droplet burning process. The hydrogen addition leads to an increase in the D2 law rate constant, k 0, of up to 16%. While AB (and residual material) participates throughout the combustion process, it dramatically impacts the combustion behavior at the end of the droplet lifetime as the concentration of AB residual grows within the droplet. This results in droplet shattering, causing fine atomization and rapid combustion of the remaining fuel. Boron is also oxidized in this short period of time, increasing the energy released. In combustors, droplet shattering could enhance mixing and increase combustion efficiency. Thus, the approach of adding compounds rich in hydrogen is a promising method to introduce H2 gas to practical combustion systems, while enhancing performance. [Copyright &y& Elsevier]

Highlights: [•] Investigates the effects of misfire on HCCI engine emissions and operating regions. [•] Examines major engine combustion parameters for misfire detection. [•] Proposes and validates a new model to detect misfire in HCCI engines (the first work on misfire detection in HCCI literature). [Copyright &y& Elsevier]

Abstract: A consistent probability density function (PDF) based combustion modeling approach for large eddy simulation of turbulent spray combustion is formulated. A Lagrangian Monte-Carlo approach for solving the PDF transport equation in the context of low-Mach number LES formulations is developed. The LES/PDF approach is used to simulate an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away from the flame front, leading to separation of the two processes. A high-temperature pre-flame zone with a stratified mixture is found to exist throughout the length of the flame. The high flow rate of the droplet-laden air prevents the flame front from propagating through this evaporated, but well-mixed fuel/air mixture. Comparison with experiments displayed large discrepancies concerning the droplet inflow conditions. In particular, the inflow turbulence is significantly modified by droplet-turbulence interactions in the injection pipe. [Copyright &y& Elsevier]

Abstract: Perovskite-type La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) mixed oxides were successfully prepared by combustion and reactive grinding method, characterized by XRD, ICP, XPS, TEM, SEM, TPR-H2, N2 adsorption–desorption and acid–base measurements and their catalytic activities for combustion of C3–C4 alkanes and ethanol were determined. LSCF materials show good catalytic performances: 100% conversion of C3–C4 and ethanol can be reached below 400 and 260°C, respectively, and activity was stable with extended time on stream and for repeated temperature cycles as well. LSCF materials seem then to be promising alternative to noble metal based catalysts for VOC oxidation. [Copyright &y& Elsevier]

Abstract: The chemical composition of flames of mixed hydrocarbon–oxygenate fuels was examined systematically for a series of laminar, premixed low-pressure propene–oxygen–argon flames blended with ethanol or dimethyl ether (DME). All flames were established at a carbon-to-oxygen ratio of C/O=0.5 at 40mbar. Propene was replaced incrementally by either additive, so that the entire range from pure propene to pure ethanol or pure DME was accessible. Experimental results have been reported previously (J. Wang et al., J. Chem. Phys. A 112 (2008) 9255–9265), including temperature profiles measured with laser-induced fluorescence (LIF) and quantitative mole fraction profiles for a large number of species obtained from molecular-beam mass spectrometry (MBMS), using electron ionization (EI) and vacuum-ultraviolet (VUV) photoionization (PI). The effects of oxygenate addition to the propene base flame were seen to result in interesting differences, especially regarding trends to form aldehydes. The entire flame series is now analyzed with a comprehensive kinetic model that combines the chemistries of propene, ethanol, and DME combustion. The flames of pure fuels are also compared with the predictions of different detailed mechanisms taken from the literature. Quantitative comparison of C1- to C6-species from this model with the measurements is provided. Major trends of propene replacement by the oxygenates are reproduced in quantitative agreement with the experiments, enabling a more detailed understanding of the combined reaction sequences in such fuel blends. [Copyright &y& Elsevier]

Abstract: Ethanol is a renewable fuel that can be used as an additive to gasoline (or its substitute) with the advantage of octane enhancement and reduced carbon monoxide exhaust emissions. However, on the standard three-way catalysts, the conversion of unburned ethanol is low because both ethanol and some of its partially oxidized derivatives are highly resistant to oxidation. A combination of first-principles density-functional theory (DFT)-based calculations and in situ diffuse reflectance infrared spectroscopy (DRIFTS) analysis was applied to uncover some of the fundamental phenomena associated with ethanol oxidation on Pt-containing catalysts. In particular, the objective was to analyze the role of the oxide (i.e., γ-Al2O3 or SiO2) substrate on the ethanol oxidation activity. The results suggest that Pt nanoparticles trap and accumulate oxygen at their surface and perimeter sites and play the role of sites that burn ethanol molecules and their partially oxidized derivatives to the final products. The γ-Al2O3 surfaces provided higher mobility of the fragments of ethanol molecules than the SiO2 surface and hence increased the supply rate of these species to the Pt particles. This in turn produces a higher conversion rate of unburned ethanol. [Copyright &y& Elsevier]

• A compact, robust and clean combustion technique is proposed to burn liquid ethanol. • A steady ethanol/air tubular flame is established in a dual swirl combustor up to 10 kW. • Flame anchoring appears as global equivalence ratio at fuel nozzle exit is below 11. This study proposes a compact dual swirl combustor to establish a steady liquid ethanol tubular flame, in which tangential air is injected through two stages. The outer intense swirl induces reversed flame on the surface wall of a concentric copper tube, and the central liquid fuel is heated to vaporize through the inner swirling air inside the copper tube. By enhancing the heat transfer process and promoting the mixing of the reactant, the overall heat output approaches 10 kW, much higher than the original combustor. With temperature measurement and heat transfer analysis, the flame stabilization mechanism has been elucidated. Two kinds of typical flame structures, a tubular flame and an anchored conical flame, have been obtained under various operating conditions. As the flow rate of inner air gradually increases, plenty of the heat aiming to vaporize the liquid fuel is taken off by the air flow, and small droplets occasionally appear downstream the nozzle; furthermore, the global equivalence ratio (Φ gl) at the nozzle exit gradually decreases, and an anchored flame appears, which interrupts the fuel mixing with outer swirling air, resulting in soot formation in some cases. Plenty of tests illustrates that as Φ gl is below 11, the flame anchoring will appear. [ABSTRACT FROM AUTHOR]

Abstract: Mixed oxides of manganese and copper with different wt% of copper have been prepared and evaluated in ethanol combustion. The co-precipitation method used for the synthesis of MnxCuy mixed oxides is adequate to obtain catalysts with excellent catalytic performance in combustion reactions. Catalysts were characterized by means of XRD, FT-IR, TPR and O2-TPD. A small amount of copper prevents manganese oxide reaching a crystalline structure. This poor crystalline structure of manganese oxide may improve the existence of oxygen vacancies giving a best performance in ethanol combustion to CO2. When the copper content increases, an extent of solid state reaction between Cu and Mn is favored and the partial oxidation of ethanol becomes more important. The incorporation of manganese into incomplete spinel structure diminishes CO2 yield. [Copyright &y& Elsevier]

In La1- x Ca x Co1- y Fe y O3 perovskites, the calcium substitution modifies the crystalline structure toward a pseudocubic one and produces an electronic unbalance, compensated by the formation of oxygen vacancies and Fe4+ ions. It also increases slightly the ethanol conversion in total combustion, compensating the detriment of catalytic activity caused by the iron substitution and it increases notably the selectivity to total oxidation. [ABSTRACT FROM AUTHOR]

Abstract: La1−x Ca x FeO3 perovskite-type oxides with x =0, 0.2 and 0.4 were prepared by the citrate method and characterised by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), surface area measurement BET, X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FT-IR), laser Raman spectroscopy (LRS), oxygen temperature-programmed desorption (O2-TPD) and temperature-programmed reduction (TPR). The citrate method shows to be simple and appropriate to obtain single phases avoiding segregation and/or contamination. Moreover, controlling the calcination temperature, specific surface areas adequate for catalysts to be used in oxidation reactions are achieved. The structure refinement by using the Rietveld method indicates that the partial calcium substitution modifies the orthorhombic structure of the LaFeO3 perovskite towards a less distorted one. From XRF and XPS, a slight surface enrichment in lanthanum and calcium was detected. XRD, FT-IR and TPR results indicated that the electronic debalance caused by the partial substitution for La3+ by Ca2+ is compensated by an oxidation state increase of a part of Fe3+ to Fe4+. O2-TPD results revealed that at a substitution level higher than x =0.2, oxygen vacancies are also formed to preserve the electroneutrality. Finally, an improvement of the catalytic activity in propane and ethanol combustion was observed on the substituted perovskites. Correlating this with the characterisation results, the active sites would be associated to the Fe4+ ions. [Copyright &y& Elsevier]

Abstract: A sensitive SIA method was developed for sulphate determination in automotive fuel ethanol. This method was based on the reaction of sulphate with barium–dimethylsulphonazo(III) leading to a decrease on the magnitude of analytical signal monitored at 665nm. Alcohol fuel samples were previously burned up to avoid matrix effects for sulphate determinations. Binary sampling and stop-flow strategies were used to increase the sensitivity of the method. The optimization of analytical parameter was performed by response surface method using Box–Behnker and central composite designs. The proposed sequential flow procedure permits to determine up to 10.0mg SO4 2− l−1 with R.S.D. <2.5% and limit of detection of 0.27mgl−1. The method has been successfully applied for sulphate determination in automotive fuel alcohol and the results agreed with the reference volumetric method. In the optimized condition the SIA system carried out 27 samples per hour. [Copyright &y& Elsevier]

Three nanoscale Mn 3 O 4 with different morphologies (hexagonal nanoplates, nan-octahedrons and nano-flowers) have been prepared and evaluated for total combustion of ethanol. The hexagonal nanoplates (Mn 3 O 4 -HNS) catalyst showed highly enhanced catalytic performance at a high space velocity (SV) (66,000 mL/(g·h)) compared to nan-octahedrons (Mn 3 O 4 -ONS) and nano-flowers (Mn 3 O 4 -FNS). The catalysts were characterized by XRD, BET, FE-SEM, HR-TEM, H 2 -TPR, XPS and ethanol-TPD. The morphology-dependent reactivity was well correlated with the exposure degree of Mn 3 O 4 (112) crystal facet determined by HR-TEM The experimental characterization results indicated that the (112) crystal facet with high surface energy can not only facilitate the adsorption/activation of ethanol and oxygen, but also be favorable for formation of more surface Mn4+ and active oxygen species. Thus, the oxidation activity of ethanol was significantly improved. This study proposes that the strategy of crystal facet engineering can be used as the design principles of developing high performance, low cost and environmentally friendly manganese oxides catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

Ethanol conversion in combustion, dry reforming and dehydrogenation over Mn 0.15 Co 2.85 O 4 spinel oxide. [Display omitted] • Cobalt-manganese spinel catalysts were evaluated for ethanol combustion, dry reforming and dehydrogenation. • Replacing of Co3+ with Mn4+ in octahedral position leads to active sites for reaction. • The catalysts are more active for combustion. • The activation for dehydrogenation and reforming take place by temperature increasing. Spinel type cobalt-manganese oxides Mn x Co 3-x O 4 (x = 0; 0.05; 0.10; 0.15) were prepared by co-precipitation method, from cobalt and manganese salts in the presence of ammonium carbonate. X-ray diffraction (XRD), texture measurements (BET/BJH), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used for their characterization. Their catalytic behavior in ethanol combustion, dry reforming with CO 2 and dehydrogenation was investigated. The results showed that the cubic structure of Co 3 O 4 , corresponding to spinel network, is not disturbed by adding manganese. Results obtained revealed that Mn 0.15 Co 2.85 O 4 catalyst, with the highest content of Mn4+ cations in the octahedral sites and oxygen defects, display superior catalytic activity compared to the others. The apparent activation energies, calculated from Arrhenius plots, are as follows: E a combustion < E a non-oxidative dehydrogenation < E a dry reforming, showing that cobalt-manganese spinel type oxides are good candidates for combustion. [ABSTRACT FROM AUTHOR]