Addition Of Ethanol Research Articles

The impact of ethanol addition on the droplet combustion mechanism of saturated and unsaturated fatty acid/fatty acid methyl ester molecules

The combustion of biodiesel requires complex analysis because it is composed of multicomponent constituents. The use of additives in biodiesel is an option widely used to improve the combustion performance of the fuel blend. The droplet combustion characteristics of single compounds of biodiesel and vegetable oil constituents with ethanol additives were investigated under normal gravity at room temperature and atmospheric pressure. This study reveals the different combustion mechanisms and their interactions with ethanol between laurate and oleate as the base fuel. Ethanol breaks the base fuel into smaller molecular aggregates, reducing the fuel blend density with many larger gaps between the clusters. Thermal expansion and child droplet ejection are key mechanisms that effectively increase the total droplet surface area, causing an increase in the diffusion contact between the fuel vapor and the air. Three mechanisms of child droplet ejection occur during the heating phase until the microexplosive combustion phase. The period of child droplet ejection during the microexplosive combustion phase is determined by the boiling point difference and the solubility level between the base fuel and ethanol. The addition of ethanol increases the burning rate of the fuel mixture with a higher peak temperature in the laurate-ethanol blend compared to the base fuel. Ethanol plays an important role in delaying the start of evaporative cooling with a significant temperature increase rate. This behavior is an effective mechanism to initiate droplet combustion with a short ignition delay time.

Quantitative evaluation of several chemical mechanisms for gasoline surrogate-ethanol blends and study of dominant chemistry under super-knock relevant conditions

A comprehensive database that covers wide ranges of temperature, pressure and equivalence ratio conditions was established for gasoline surrogate fuels composed of n-heptane, iso-octane, toluene with and without ethanol addition. The database includes ignition delay time measurements in shock tubes and laminar flame velocity measurements which are relevant combustion properties under super-knock relevant conditions. Due to the lack of reaction pathways for low-temperature iso-octane combustion and ethanol oxidation in Caltech mechanism, an updated mechanism has been constructed. The update has been carried out as follows: (i) changing the iso-octane sub-mechanism, (ii) adding an ethanol sub-mechanism, and (iii) modifying thermodynamic and kinetic parameters for few species and reactions for removing collision limit violation. The predictive capabilities of the modified Caltech mechanism and of three reaction models developed for n-heptane/iso-octane/toluene/ethanol based mixtures have been quantified using the model evaluation method of Olm. Significant improvement of the combustion properties predictions by the modified Caltech model has been demonstrated by the lower error value. For the prediction of ignition delay time, the updated Caltech mechanism shows better performance than the other models, especially in the high-temperature regime. Error maps were drawn over wide ranges of thermodynamic conditions to show the overall performance of all the evaluated mechanisms. For the prediction of laminar burning velocity, the modified Caltech mechanism performs better for most cases. Laminar burning velocity is always over-estimated by Livermore’s mechanism. The new mechanism was employed to determine the most important chemical pathways under super-knock relevant conditions corresponding to the following thermodynamic states: (630 K, 2.3 MPa), (750 K, 6.0 MPa), (720 K, 2.8 MPa), and (1000 K, 12.0 MPa). The modified Caltech model, or reduced versions of it, could be employed in future work to investigate super-knock for realistic gasoline surrogate.

Removal of 4-Ethylphenol and 4-Ethylguaiacol, from Wine-like Model Solutions, by Commercial Modified Activated Carbons Produced from Coconut Shell

When present in high concentrations in red wine, 4-ethylphenol (4-EP) and 4-ethylguaiacol (4-EG) are responsible for the introduction of unpleasant aromas, which causes wine depreciation. The work presented concerns the performance of textural and chemical-modified activated carbons (ACs), produced from coconuts shells, in the treatment of spoiled wines. ACs were submitted to basic and acid treatment, by impregnation into solutions containing NaOH and HNO3, respectively. Modified ACs showed only a small, but noticeable, increase in apparent surface area and micropore volume when compared to the original AC. However, the surface chemistry underwent significant changes. The ability of modified ACs to remove 4-EP and 4-EG, which cause the off-flavor known as “Brett character”, from wine-like solutions has been successfully achieved. On the systems studied, 4-EG was retained in greater extension, but 4-EP was retained more strongly on the surface of the ACs. Ethanol was found to compete with 4-EP and 4-EG for the adsorptive centres. However, when 4-EP and 4-EG were present in the same solution, the addition of ethanol promoted a cooperative effect and favoured the adsorption of both compounds. It should be noted that the modified ACs were able to eliminate 4-EP and 4-EG to levels below their sensory perception thresholds referred for red wine.

Research based on optimization model of C4 olefins preparation

In this paper,through the design of catalyst combination and temperature control,a mathematical model was established to explore the process of ethanol catalytic coupling to produce C4 olefins.Firstly,according to the data in the attachment,temperature was taken as the main variable,and ethanol conversion rate and C4 olefins selectivity were taken as dependent variables to solve the binary regression function. Then,ethanol conversion rate and C4 olefins selectivity were imported into the model as master columns.It was found that temperature had the greatest influence on ethanol conversion and C4 olefins selectivity.Then the BP neural network model was constructed,and different catalyst combinations and temperature data were substituted.Through analysis,the maximum yield of C4 olefin was 53.58%,the filling ratio was 0.49,the Co loading was 2,the ethanol adding rate was 0.3,and the temperature was 450℃.Finally,considering the highest C4 olefin yield as the starting point,additional control experiments were set from the perspectives of whether to use HAP-ethanol,adjacent temperature,ethanol addition rate,Co loading capacity and charging ratio,respectively,to verify the rationality of the neural network model.

Viscosity Reduction and Mechanism of Aquathermolysis of Heavy Oil Co-Catalyzed by Bentonite and Transition Metal Complexes

At present, the research on aquathermolysis catalysts mainly focuses on the catalytic effect of external catalysts on the reaction, ignoring the fact that external catalysts will form complexes with in situ inorganic minerals after entering the reservoir. In this paper, we investigated the effects of transition metal complexes as external catalysts and bentonite as in situ catalysts on aquathermolysis, respectively. Meanwhile, the aquathermolysis reaction co-catalyzed by external and in situ catalysts was further investigated. The results show that the transition metal complexes exhibited good co-catalysis with bentonite. The viscosity reduction rate can reach 73.47% at 200 °C and 4 h with 0.1 wt.% of catalyst (NAD–Zn) addition. The addition of ethanol under the same reaction conditions will further increase the viscosity reduction rate to 84.59%. The results of thermogravimetric analysis, component analysis and boiling range analysis of heavy oil show that the heavy components in heavy oil are cracked into light components after the aquathermolysis. The results of elemental analysis show that the heteroatoms in the heavy oil were removed and the quality of the crude oil was improved. The results of GC–MS analysis of the model compounds showed that the process of aquathermolysis was mainly through the cleavage of C–C, C–N and C–S bonds to crack the macromolecules into small molecules, and then achieve the effect of viscosity reduction. The main mechanism of catalyst action is the acidic center on the surface of the bentonite and the coordination bonds formed by the transition metal complexes with the heteroatoms.

The effect of ethanol on fibrillar hydrogels formed by glycyrrhizic acid monoammonium salt

MotivationThe monoammonium salt of glycyrrhizic acid (AGA) is known to form fibrillar hydrogels and few studies regarding self-assembly of AGA have been published. Yet, the understanding of the fibrillar microstructures and the gelation remains vague. Thus, we attempt to achieve a deeper understanding of the microstructures and the gelation process of binary solutions of AGA in water. Further, we examine the effect of ethanol on the microstructures to pave the way for potential enhancement of drug loading in AGA hydrogels. ExperimentsA partial room temperature phase map of the ternary system AGA/ethanol/water was recorded. Small-angle X-ray and neutron scattering experiments were performed over wide ranges of compositions in both binary AGA/water and ternary AGA/ethanol/water mixtures to get access to the micro-structuring. FindingsBinary aqueous solutions of AGA form birefringent gels consisting of a network of long helical fibrils. ‘Infinitely’ long negatively charged fibrils are in equilibrium with shorter fibrils (≈25 nm), both of which have a diameter of about 3 nm and are made of around 30 stacks of AGA per helical period (≈9nm), with each stack consisting of two AGA molecules. The interaxial distance (order of magnitude ≈20 nm) varies with an almost two-dimensional swelling law. Addition of ethanol reduces electrostatic repulsion and favors the formation of fibrillar end caps, reducing the average length of shorter fibrils, as well as the formation of small, swollen aggregates. While the gel network built by the long fibrils is resilient to a significant amount of ethanol, all fibrils are finally dissolved into small aggregates above a certain threshold concentration of ethanol (≈30 wt%).

Polyhydroxybutyrate production in one-stage by purple phototrophic bacteria: Influence of alkaline pH, ethanol, and C/N ratios

This work aimed to evaluate the effect of alkaline pH, nutrient limitation, nitrogen source, C/N ratio, and ethanol addition on polyhydroxybutyrate (PHB) production by a photoheterotrophic mixed culture enriched in Rhodopseudomonas palustris. The results demonstrated the natural alkalinization of the culture medium was enough to induce PHB accumulation in the mixed culture. The combination of alkaline pH, nitrogen, sulfur, or phosphate deficiency negatively affected polymer production. The incorporation of glutamate for biomass synthesis was better than that of ammonium, which had a positive effect on PHB production. Interestingly, ethanol addition improved the PHB accumulation by 25 %, but without consumption. PHB production improved at low C/N ratios, where 27 ± 0.9% of the carbon source was transformed into biopolymers. The evaluated factors allowed the biomass PHB content to increase by 60%, reaching PHB production of 219 ± 5 mg/L. The PHB production by the photoheterotrophic mixed culture is associated with growth, allowing the PHB production in one stage. That has significant advantages in technical-practical terms, such as reducing the time of the process, dispensing with the separation of biomass from the feast phase to the famine phase, and requiring a single reactor.

Experimental and model-based analysis of combustion and auto-ignition of gasoline and three surrogate fuels in a single-cylinder research engine operated under knocking conditions

A systematic analysis of knocking combustion at the knock limit in a single-cylinder research engine is conducted. Both experimental and numerical methods are used to investigate the physical phenomena involved in knocking combustion. While real gasoline fuel can be used directly in experimental studies, this is not feasible in numerical simulations. Here, surrogate fuels with a reduced number of components defined to match the desired properties, such as knock resistance, are employed. In this work, standard gasoline and three surrogate fuels are considered. Differences in composition complexity are covered by selecting isooctane and two toluene reference fuels (TRF) with ethanol addition, all of which exhibit negative temperature coefficient (NTC) behavior in which auto-ignition delay times increase with increasing temperature. Spark timing sweeps at two engine speeds show that the knock resistance of the fuels correlates with the respective research octane number (RON). Isooctane is found to have higher knock resistance and higher sensitivity to engine speed than standard gasoline. One of the two TRFs studied shows good agreement with gasoline in terms of combustion and knock characteristics. The lower knock resistance of the other TRF indicates a non-linear dependence between mixture composition and knock resistance. A strong relative increase in knock resistance at higher engine speeds suggests a possible influence of NTC behavior at lower engine speeds. In the subsequent model-based analysis, the fuel influence on combustion and auto-ignition is investigated, and the laminar burning velocities are found to correlate well with the observed heat durations. While auto-ignition may be triggered by a cool spot at the lower engine speed and at operating conditions within the NTC regime, auto-ignition at the higher engine speed is assumed to be initiated by hot spots. These different mechanisms for initiating auto-ignition were identified as a potential explanation for the different knock resistances observed.

The Effects of Ethanol and Rutin on the Structure and Gel Properties of Whey Protein Isolate and Related Mechanisms

The effects of different levels of rutin (0, 0.05%, 0.1%, 0.2% and 0.3% w/v) and ethanol on the structure and gel properties of whey protein isolate (WPI) were examined. The results showed that the addition of ethanol promoted the gel formation of WPI. The addition of rutin increased the gel strength of WPI and maintained the water-holding capacity of the gel. Ethanol caused an increase in thiol content and surface hydrophobicity, but rutin decreased the thiol content and surface hydrophobicity of WPI. The particle size, viscosity and viscoelasticity of WPI increased at rutin levels of 0.2% and 0.3%, indicating that rutin caused cross-linking and aggregation of WPI, but rutin had no significant effect on the zeta-potential, indicating that electrostatic interactions were not the main force causing the changes in protein conformation and gel properties. Ethanol and rutin improved the gel properties of WPI possibly by inducing cross-linking of WPIs via hydrophobic and covalent interactions.

Effect of diffusion oxygen enrichment on soot formation in coflow diffusion flames of gasoline-surrogate fuel doped with ethanol

• Combined effect of diffusion oxygen enrichment and ethanol addition to gasoline on soot was investigated numerically. • The dominant mechanism of particle mass growth after ethanol addition does not change with the increasing oxygen concentration. • Inhibition of ethanol addition and promotion of diffusion oxygen enrichment on soot attribute to PAH condensation and HACA, respectively. • Coupling effect between oxygenated fuel and diffusion oxygen is strongest in the surface growth. • Ethanol addition and diffusion oxygen enrichment have opposite effect on particle oxidation. The combined effect of ambient oxygen enhancement and oxygenated fuel addition is expected to improve combustion efficiency and control soot formation. In this work, the effect of diffusion oxygen enrichment on soot formation and the particle dynamics mechanism in coflow diffusion flames of gasoline-surrogate doped with ethanol were investigated numerically. The results showed that the peak temperature and SVF of ethanol-gasoline flames increase linearly with the increase of diffusion oxygen concentration, while the ethanol addition reduces the peak temperature and SVF. The action mechanism of diffusion oxygen enrichment on final soot formation is the result of the competition between residence time and particle dynamics, while the action mechanism of ethanol addition is the combined effect of residence time and particle dynamics. From the perspective of particle dynamics, the dominant mechanism of particle growth in gasoline flame changes with the increase of diffusion oxygen concentration. When the oxygen concentration exceeds 25%, HACA gradually replaces PAH condensation as the main mechanism of particle mass growth. However, after adding ethanol, HACA is always the dominant mechanism of particle mass growth and does not change with the increasing oxygen concentration. The inhibition of ethanol addition on soot is mainly achieved by reducing the PAH condensation rate, while the promotion of diffusion oxygen enrichment on soot is largely attributed to the increasing temperature and HACA rate. In addition, there is a coupling effect between the oxygenated fuel addition and the diffusion oxygen enrichment on the inhibition of particle dynamics. The coupling effect is strongest in the surface growth of particles, and is further enhanced with the increasing ethanol ratio and oxygen concentration. Ethanol addition and diffusion oxygen enrichment do not change the dominant role of O 2 oxidation in particle oxidation, but they have opposite effect on particle oxidation.

A numerical study on soot formation in methane-ethanol diffusion flames

• Soot volume fraction and particle number density increase with ethanol blending ratio. • The degree of soot enhancement decreases with further increase in ethanol blending ratio. • Effect of ethanol on soot concentration follows the order: chemical > dilution > thermal. • Thermal effect has a dominant influence on the flame temperature, but not on soot. • Ethanol addition promotes the HACA pathway and surface growth mechanism. Numerical simulation was carried out to investigate the effect of ethanol addition on the soot formation characteristics of methane diffusion flame. The ethanol blending ratio in methane ranged from 0 to 40 % in terms of the carbon contribution, ensuring a constant carbon flow rate for all cases. The sooting diffusion flames were modelled in an open-source environment, OpenFOAM, whereby-two different soot modelling approaches were attempted, including one detailed soot model and one semi-empirical soot model. Numerical results revealed that ethanol addition increased the soot volume fraction; however, further increase in the ethanol blending ratio (>20 %) reduced the relative enhancement of the soot concentration. Decoupling analysis was conducted to study the dilution, thermal, and chemical effects of ethanol separately. It was found that the dilution effect increased with the ethanol blending ratio. Also, the flame temperature was primarily affected by the thermal effect of ethanol. Despite these factors, the chemical effect of ethanol still played a dominant role in increasing soot formation. Analysis of the soot formation pathway revealed that ethanol addition promoted soot formation mainly through the acetylene addition reactions and polycyclic aromatic hydrocarbons (PAHs) addition reactions, which contributed to the hydrogen-abstraction-acetylene-addition (HACA) and surface growth mechanisms, respectively. Soot oxidation was enhanced with ethanol addition, which resulted in greater soot reduction; however, the overall effect of ethanol on soot formation remained positive.

Fuel and Boiling Point Analysis in Mixing Between Ethanol with Bio-Diesel and Diesel Fuel

Global warming can be caused by pollution in the environment. Pollution comes from combustion from fossil fuels. Therefore, it is important to study some renewable energies for alternative fuels other than fossil fuels. Blending between ethanol to biodiesel and diesel fuel is one practical solution that can be applied. This research was conducted by making a sample of the fuel to be tested with a mixture of ethanol - biodiesel formula (10%, 25% and 35%) and for a mixture of ethanol - diesel fuel (10%, 25% and 35%). The fuel properties were tested such as viscosity, density, boiling fuel, and cetane index. The results show that the addition of ethanol to biodiesel and diesel fuel can produce better fuel properties.

Dutasteride nanoemulsion preparation to inhibit 5-alpha-hair follicle reductase enzymes in the hair follicle; an ex vivo study.

Alopecia is a treatable disorder that usually occurs due to high levels of 5-alpha dihydrotestosterone in hair follicles. To enhance the storage capacity of hair follicles and alleviate the inherent characteristics of dutasteride, 5-alphareductaseinhibitor, a prolonged-release nanocarrier was synthesised, and its influence on rat abdomen's skin was investigated. Results showed the lower ratio of S/Co (higher ethanol concentration) increased the hydrodynamic nanocarriers' particle size due to thermodynamic disturbance and Ostwald ripening. In contrast, an increase in surfactant through a decrease in interfacial tension resulted in smaller nanocarriers of 32.4nm. Moreover, an increase in viscosity had an inverse correlation with the nanoemulsions' particle size. Nanocarriers containing ethanol showed less entrapment efficacy, perhaps due to the rapid dissolution of dutasteride into ethanol during nanoemulsification, while, based on Stokes' equation, the addition of ethanol resulted in smaller particle size and stability of the system. Skin permeation analysis using Franz diffusion cells showed nanocarriers could pass through the skin and release dutasteride for 6days. In conclusion, the optimum concentration of ingredients is decisive in guaranteeing the ideal particle size, stability, and skin permeation of nanocarriers. The Present dutasteride nanocarrier would promise a prolonged and sustained-release drug delivery system for Alopecia therapy.

Effective hexanol production from carbon monoxide using extractive fermentation with Clostridium carboxidivorans P7

This study achieved high production of hexanol via gas fermentation using Clostridium carboxidivorans P7 by extracting hexanol from the fermentation broth. The hexanol extraction efficiency and inhibitory effects on C. carboxidivorans P7 of 2-butyl-1-octanol, hexyl hexanoate and oleyl alcohol were examined, and oleyl alcohol was selected as the extraction solvent. Oleyl alcohol was added at the beginning of fermentation and during fermentation or a small volume of oleyl alcohol was repeatedly added during fermentation. The addition of a small volume of oleyl alcohol during fermentation was the most effective for CO consumption and hexanol production (5.06 g/L), yielding the highest known hexanol titer through any type of fermentation including gas fermentation. Hexanol production was further enhanced to 8.45 g/L with the repeated addition of oleyl alcohol and ethanol during gas fermentation. The results of this study will enable sustainable and carbon–neutral hexanol production via gas fermentation.

Transesterification of castor oil catalyzed by a fermented solid produced by Burkholderia contaminans using a bioreactor coupled with ultrasound irradiation.

In this work, ultrasound was used to assist the ethanolysis of castor oil in a solvent-free system, catalyzed by a dry fermented solid containing the lipase from Burkholderia contaminans (BCFS). Reactions were done at 45°C. The maximum conversion in Erlenmeyer flasks was 71% in 96h, using a loading of 9% (mass of BCFS in relation to the mass of triacylglycerols in the castor oil) and a molar ratio of ethanol:oil of 6:1, with addition of ethanol in 12 steps. In a packed-bed reactor containing 12g of BCFS, the conversions were 78% in 48h, and 83% in 72h with an ethanol to oil molar ratio of 3:1 and treatment with an ultrasound probe, with maximum power of 500W, frequency of 20kHz, and 75% of the maximum power. These results are promising given that, with an ultrasound assisted bioreactor, a higher conversion in a shorter time was achieved, with a lower ethanol to oil molar ratio than was the case in the Erlenmeyer flasks without ultrasound.

In situ XAFS study on chemical states of Co and Ir nanoparticles under conventional growth condition of single-walled carbon nanotube via alcohol catalytic chemical vapor deposition

In situ X-ray absorption fine structure (XAFS) analysis was performed on Co and Ir catalysts during single-walled carbon nanotube (SWCNT) growth via alcohol catalytic chemical vapor deposition (Ar/H2 carrier gas). The Co catalysts were partially reduced during heating to 800 °C, and partially carbonized during SWCNT growth upon ethanol addition. The Ir catalysts were reduced during heating and became metallic at 900 °C; the Ir catalysts remained metallic during SWCNT growth upon ethanol addition. The chemical states of the catalyst particles varied with the metal properties during SWCNT growth; thus supporting the growth model proposed using atomistic computer simulations.

Effect of Ethanol on Preparation of Konjac Emulgel-Based Fat Analogue by Freeze-Thaw Treatment

In the current study, a method using ethanol to modulate the texture properties of konjac gel during freeze-thaw process was used to prepare konjac emulgel-based fat analogue. A certain amount of ethanol was added to konjac emulsion, heated to form a konjac emulgel, then frozen at −18 °C for 24 h, and finally thawed to obtain konjac emulgel-based fat analogue. The effects of different ethanol contents on the properties of frozen konjac emulgel were explored, and data was analyzed by one-way analysis of variance (ANOVA). The emulgels were compared with pork backfat in terms of hardness, chewiness, tenderness, gel strength, pH, and color. The results showed that the konjac emulgel with 6% ethanol had similar mechanical and physicochemical properties to pork backfat after freeze-thaw treatment. The results of syneresis rate and SEM showed that adding 6% ethanol could not only reduce the syneresis rate, but also effectively weaken the damage to the network structure caused by freeze-thaw treatment. The pH value of konjac emulgel-based fat analogue was between 8.35–8.76, and the L* value was similar to that of pork backfat. The addition of ethanol provided a new idea for the preparation of fat analogues.

Effect of Sorbic Acid, Ethanol, Molasses, Previously Fermented Juice and Combined Additives on Ensiling Characteristics and Nutritive Value of Napiergrass (Pennisetum purpureum) Silage

The effects of sorbic acid, ethanol, previously fermented juice and their combined additives on fermentation quality and residual water-soluble carbohydrates (WSC) of napiergrass (Pennisetum purpureum) were herein investigated. There were two experiments in total. The treatments of experiment 1 were as follows: control (no addition); sorbic acid at 0.1%, S; molasses at 1.0%, M; previously fermented juice at 5 mL/kg, P; SP; SM; SPM. The treatments of experiment 2 were as follows: control (no addition); ethanol at 1.5%, E; molasses at 1.0%, M; previously fermented juice at 5 mL/kg, P; EM; EP; EPM. The laboratory silos (10 L) were kept at room temperature (~25 °C), and opened after 120 days of ensiling and the chemical compositions of silage were analyzed. Sorbic acid addition significantly (p < 0.05) decreased the silage pH and increased the residual WSC and lactic acid (LA) contents as compared with control. Ethanol addition decreased pH, acetic acid (AA) and volatile fatty acids (VFAs) contents, and increased the ratio of LA/AA, LA and residual WSC contents. Molasses addition increased ratios of LA/AA and enhanced WSC content used by lactic acid bacteria (LAB). The PFJ addition increased AA and ammonia nitrogen/total nitrogen (AN/TN) and decreased the LA contents. Comparing the fermentation quality among all silages in the present study, the combined additives SM and EM performed best in improving the silage quality of napiergrass.

Metallurgical Residue-Derived Cu–ZnO-Based Catalyst for CO2 Hydrogenation to Methanol: An Insight on the Effect of the Preparation Method

Valorization of residual materials in the development of catalytic materials has an appealing potential from the perspective of a sustainable development. For the first time, Fe/Mg-containing metallurgical waste (UGSO) was utilized as a support for the development of innovative catalysts for CO2 hydrogenation into methanol. A series of different CuZn/UGSO catalysts were developed by conventional and modified deposition–coprecipitation methods. The addition of Cu/Zn into the structure of Fe3O4/MgxFeyO4 was found to improve Cu2+ and Zn2+ dispersion, while the presence of MgO favors methanol selectivity. Compared to 10Cu7.5Zn/UGSO (10 wt % Cu, 7.5 wt % Zn), the higher methanol yield obtained over 10Cu7.5Zn/UGSO–EtOH (10 wt % Cu, 7.5 wt % Zn, ethanol addition after coprecipitation) is a result of both higher CO2 conversion [attributed to (i) finer particle sizes of CuO and ZnO, (ii) a higher Cu0/Cu+ percentage, and (iii) higher oxygen vacancies and number of strong basic sites on the catalyst surface] and higher methanol selectivity [assigned to (i) the stronger interaction of Cu and ZnO and (ii) a higher number of medium basic sites] in comparison with its counterpart. This residue-based catalyst offers a 150% higher methanol yield than a commercial Cu-based methanol synthesis catalyst at 260 °C and 20 bar. These promising results can open a window to the utilization of this residue as a catalytic support in other CO2 hydrogenation processes.

Temperature Stratification Induced Ignition Regimes for Gasoline Surrogates at Engine-Relevant Conditions

ABSTRACT End-gas auto-ignition leading to knocking combustion is one of the major barriers to achieving higher thermal efficiencies in downsized boosted spark-ignition engines. Despite the available framework addressing hotspot-induced ignition (detonation peninsula), a quantitative investigation on hotspot-induced auto-ignition of gasoline surrogates is yet to be done. In particular, the effect of negative temperature coefficient (NTC) chemistry on the distribution of the ignition modes in the detonation peninsula is still missing. Using the established one-dimensional (1D) theoretical and computational framework, the effect of average temperature (including NTC range), initial pressure, and ethanol addition are investigated. Moreover, appearance of NTC chemistry-related events i.e. coolspots, secondary ignition kernels, and off-centered ignition are analyzed using 1D simulations. The results are as follows. 1) NTC chemistry affects the distribution of ignition regimes in detonation peninsula and the dynamics of the front propagation via altering the reactivity gradient. 2) NTC chemistry increases the temperature gradient range associated with the detonation regime. 3) NTC may inhibit detonation development by simultaneously promoting the spontaneous/supersonic ignition modes. 4) An ethanol blend decreases the knock propensity; however, lower ignitability may promote detonation development and the appearance of strong shock waves. 5) Finally, detonation may result in a normal knock at lower initial pressures (20 bar). However, at elevated initial pressures (50 bar), detonation is noted to yield pressure intensities resembling super-knock.