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The main concerns of utilizing jojoba biodiesel in CI engines is that it has a high viscosity and high NOx formation. Therefore, this article purposes in endeavoring to improve the combustion and emission parameters of a CI engine working with diesel/jojoba biodiesel blend and higher alcohols under various engine loads. The higher alcohols typically are n-butanol, n-heptanol, and n-octanol, which are combined with 50% diesel, 40% of jojoba biodiesel at a volume portion of 10%, and they are designated as DJB, DJH, and DJO respectively. The jojoba biodiesel is manufactured via a transesterification process with facilitating mechanical dispersion. The findings display that there is a drop in pmax and HRR for DJB, DJH, and DJO blends compared to pure diesel fuel, whereas the combustion duration and ignition delay are extended. The brake specific fuel consumption is enlarged. Concerning engine emissions, the NOx formation is reduced while the CO, UHC, and soot emissions are increased for DJB, DJH, and DJO mixtures. It can be deduced that combining high fractions of jojoba biodiesel with C4, C7, and C8 alcohols have the feasible to accomplish low NOx formation in the interim having high thermal efficiency level.

In this study, the effect of fuel temperature on cavitation inception, cavitation development structure, flow regime and near-field spray was explored, especially focus was put on a special kind of vortex-induced string-type cavitation and its effects on spray behavior. It can be seen that the higher the fuel temperature, the smaller the injection pressure corresponding to the cavitation inception is, and the faster it develops under the same injection pressure. The growth of geometry-induced near-wall cavitation at different fuel temperatures is weaker than that of vortex-induced string cavitation. The single initial bubble can be an origin for inducing the string cavitation after entering the nozzle orifice, whose intensity is larger at the higher fuel temperature. Although the effect of initial bubbles at the lower fuel temperature is weaker, continuous initial bubbles can still induce the formation of string cavitation and then stabilize it in the nozzle orifice. String cavitation initiated at the outlet is undemanding to occur at a higher temperature, and it becomes challenging to develop towards the inlet when the injection pressure increases. The frequency of the cloud cavitation shedding increases with the higher fuel temperature incurring a reduction in fuel viscosity. The variation of cavitation patterns at different fuel temperatures in diesel nozzles: The string cavitation intensity increases gradually as the injection pressure increases. Meanwhile, the growth of string cavitation area becomes faster with growing the temperature. When the injection pressure is increased to 0.6 MPa, further augment of the cavitation area is significantly limited due to the space limitation of the orifice, resulting in a slowdown of the growth rate. The development characteristics of string cavitation with temperature (h = 1 mm)

Based on a 10-kW organic Rankine cycle (ORC) experimental prototype, the system behaviors using a plunger pump and centrifugal pump have been investigated. The heat input is in the range of 45 kW to 82 kW. The temperature utilization rate is defined to appraise heat source utilization. The detailed components’ behaviors with the varying heat input are discussed, while the system generating efficiency is examined. The exergy destruction for the four components is addressed finally. Results indicated that the centrifugal pump owns a relatively higher mass flow rate and pump isentropic efficiency, but more power consumption than the plunger pump. The evaporator pressure drops are in the range of 0.45–0.65 bar, demonstrating that the pressure drop should be considered for the ORC simulation. The electrical power has a small difference using a plunger pump and a centrifugal pump, indicating that the electric power is insensitive on the pump types. The system generating efficiency for the plunger pump is approximately 3.63%, which is 12.51% higher than that of the centrifugal pump. The exergy destruction for the evaporator, expander, and condenser is almost 30%, indicating that enhancing the temperature matching between the system and the heat (cold) source is a way to improve the system performance.

The object of the current work is to enhance diesel engine performance utilizing diesel/Jatropha biodiesel/n-butanol blends with the addition of carbon nanomaterials, which are mainly multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and graphene oxide (GO). The results showed that Jatropha biodiesel and Jatropha biodiesel-diesel (JB20) mixed with GNPs, GO, and MWCNTs exhibited significant improvement in combustion and emission characteristics. The same findings are achieved with a Jatropha biodiesel-n-butanol mixture (JME40B) with the addition of these additives. The peak pressure and brake specific fuel consumption were higher compared to the base fuel. Additionally, the addition of a high blending ratio of n-butanol with Jatropha biodiesel with the existence of carbon nanomaterials has the potential to achieve new norms of NOx, CO, and UHC emissions while also keeping a high thermal efficiency level. Finally, the results illustrate that the concentration of 50 mg/L had maximum improvement in both the engine combustion and emission parameters.

The magnesite and bauxite mines are a major source for some minerals and metals. The tailings of these magnesite and bauxite mines contains massive amount of Mn. (3221.2 +/- 6.51 & 7102.8.4 +/- 10.24), Cd (40.95 +/- 2.12 & 892.86 +/- 8.48), Zn (951.08 +/- 4.31 &724.12 +/- 3.18), and Pb (425.8 +/- 5.21 & 812.13 +/- 9.19 mg Kg(-1)) with alkaline and acid pH respectively. In the microbial diversity analysis, the results 8 (Thiobacillus thiooxidans, Leptospirillum ferrooxidans, Acetobacter methanolicus, T. intermedius, Bacillus cereus, Sulfobacillus acidophilus, Methylobacterium sp, and Thiobacillus ferooxidans) and 12 (Serratia marcescens, Metalogenium symbioticum 1, Metallogenium symbioticum 2, Bacillus alcalophilus, Aminobacter sp, Naumaniella neustonica, Staphylococcus aureus 1, Methylbacillus sp, Pandoraea sputorum, Acenetobacter sp, S. aureus 2, Pseudomonas aeruginosa) bacteria species were isolated from bauxite and magnesite mine tailings. The fungus such as Rhizopus arrhizus, Mucor sp, Aspergillus niger and Penicillium sp were obtained in both acid and alkaline environment. Among this microbial diversity, P. sputorum and B. cereus (identified through 16S rDNA sequencing) were shown better resistance to these four metals for up to 250 mg L-1. The bacterial diversity indexes, concludes that there was least diverse among the three sites. The evenness/equitability index also conform lower level of variation among these sites. (C) 2019 Elsevier Ltd. All rights reserved. info:eu-repo/semantics/publishedVersion

To use methanol as a mono-fuel in large bore marine engines, a distributed jets ignition combustion mode was applied on a 320 mm-bored engine, in which pre-chamber initiated jets were employed to ignite the in-cylinder lean mixtures and to enhance the flame propagation. A preliminary numerical study was carried out to investigate the effects of in-cylinder excess air ratio and ignition timing on combustion characteristics and performances of the engine. Conditions with excess air ratios ranged from 2.0 to 2.8 and ignition timings ranged from −8°CA ATDC to the top dead center were calculated. The numerical results show that, under the distributed jets ignition combustion mode, the in-cylinder lean methanol-air mixtures could be reliably ignited and the heat release rates showed a firstly slow and then rapid trend, resulting in high thermal efficiencies and low NOx emissions, which could meet for the IMO Tier III emission regulations without aftertreatment. Moreover, with the increase of the in-cylinder excess air ratio and the delaying of the ignition timing, the in-cylinder pressure, the peak pressure rising rate, the ringing intensity and the NOx emissions were continuously decreased. As the in-cylinder mixture becoming leaner, the combustion efficiency firstly kept constant and then rapidly dropped when the excess air ratio increased to 2.4, resulting in a peak value of the indicated thermal efficiency (49.2%) at this excess air ratio. According to the numerical results, a combustion control strategy was proposed: when the brake mean effective pressure was below 1.8 MPa, the in-cylinder excess air ratio was controlled at 2.4 and coupled with an earlier ignition timing to obtain high thermal efficiency, and when the brake mean effective pressure was higher than 1.8 MPa, the in-cylinder excess air ratio was controlled at 2.1 and coupled with a later ignition timing, thereby to achieve high power density.

On the test bench of the high-pressure common rail injection system with a high-speed camera, the visualization experiments of real-size tapered hole nozzle of the diesel engine were performed to obtain needle valve lift, string cavitation in the sac chamber and nozzle hole, residual bubbles and near-field spray characteristic. And a high-pressure sensor was utilized to measure the real pressure fluctuation for the nozzle inlet. On the basis, under different control strategies, the comprehensive effects of needle valve throttling and pressure fluctuation for nozzle inlet on the internal flow and near-field spray characteristic under the multiple injections were studied. Research indicated that the spray cone angle and the spray area ratio in the main injection stage shows a boot-shaped increasing trend of slowness and then abruptness. In the development stage, the spray cone angle fluctuates in a little range (20°-30°); In the saturation phase, the spray cone angle fully develops and the fluctuation is relatively stable (40°-50°). As the throttling position shifts, there is an obvious string cavitation process, and the spray cone angle increases suddenly. In the process of pre-injection and post-injection, needle valve and valve seat throttling and lift instability cause fuel pressure fluctuation in the control chamber and sac, which is the main immediate cause of the fluctuation of low fuel injection quantity. Besides, the interval time between multiple injections, on the one hand, affects the state of residual bubbles in the nozzle before the next injection beginning, on the other hand, it also affects the stability of the inlet pressure at this time. The flow transition in the low-lift zone and the cavitation changing in the high-lift stable zone also cause transformation in the form of pressure fluctuation.

Microalgal feedstocks have gained tremendous potential for sustainable biofuel production in recent years. For biofuel processing, thermochemical, biochemical, and transesterification processes are used. Many researchers have recently become interested in the hydrothermal liquefaction of microalgae. Renewable biofuel production from microalgae, as well as a broad range of value-added co-products, describe its potential as a biorefinery feedstock from this perspective. Microalgae convert solar energy into carbon storage compounds, such as TAG (triacylglycerols), which can then be converted into biodiesel, bioethanol, and bio-methanol. Microalgae are considered to be the most attractive source of biofuel production for all the organisms used. This review explored the percentage of oil content, chemical composition, and lipid content of microalgae. This analysis depicts the various aspects of microalgal species for biofuel conversion. Also, other bioenergy and value-added items are discussed briefly.

Hydrothermal liquefaction (HTL) of microalgae produces high amount of water-insoluble organic compounds, the biocrude oil. Using high-growth-rate Spirulina platensis as feedstock, product fraction distribution and biocrude oil chemistry from HTL at a temperature of 240–300 °C under acidic, neutral and alkaline condition were studied. Positive effects on biocrude oil yield were only found with KOH and acetic acid, and these effects were stronger under milder HTL conditions. FT-ICR MS showed that O2 class in the biocrude was high due to higher carbohydrate in the biomass, numbers of N3O5-6 species present in the sample from acetic acid run, indicating its less decarboxylation ability. GC–MS showed more ketones and amides were formed from fatty acids in catalytic HTL, and this effect was sensitive toward reaction temperature. GPC suggested more light volatiles were in biocrude from KOH run, while analysis from NMR, FT-IR and elemental confirmed its high oil quality.

This study investigated the transformation of N‑heterocycle compounds during sewage sludge pyrolysis process. The reaction pathways for evolution of the products especially the N-containing organics such as amino acids‑N were analyzed in detail. NH3 is the main N-containing gaseous product during the pyrolysis and its concentration was increased with the increasing temperature. Phenolic compounds, hydrocarbons and heterocyclic compounds were the main component in liquid products. The in situ FT-IR study showed that the labile inorganic ammonium salt decomposition proceeded to completion below 500 °C. Above 500 °C N‑heterocycle compound was formed and then it was decomposed, while above 600 °C nitrile started to decompose. NH3 formation main originates from the decomposition of N‑heterocyclic compounds and nitrile. Proteins during the pyrolysis, as verified by XPS, were mainly converted into inorganic nitrogen. In addition, the Py-GC–MS results showed that large amount of N‑heterocyclic compounds were found in amino acid‑N pyrolysis products. The transformation paths for the amino acids with different chemical structures were distinct. Except N‑heterocyclic amino acids, long chain aliphatic amino acid also can form N‑heterocyclic compounds through cyclization. In addition, the decomposition of the intermediates of N‑heterocyclic compounds form small molecular compounds or while the polymerization of the intermediates forms macromolecule compounds. The amino acids with heterocycle structure were disrupted to form heterocycle and aliphatic intermediate. The plausible mechanism of sewage sludge pyrolysis was proposed.

Cavitation is quite important for the diesel spray atomization and the combustion of air–fuel mixture. In this study, a high-speed CMOS camera equipped with a long-distance microscope was utilized to capture the transient cavitating flow and spray characteristics in real-size optical nozzles with needle motion. The transient cavitation images, including geometry-induced cavitation and vortex-induced string cavitation, were captured clearly in cylindrical-orifice nozzles and tapered-orifice nozzles, respectively. Besides, the agglomerated phenomenon of geometry-induced cavitation was visually captured and analyzed for the first time. It was found that the string cavitation in nozzle excites the instability of spray cone angle and it is synchronized with increase of spray cone angle. In addition, it is the string cavitation but not geometry-induced cavitation has a much larger contribution to the increase of spray cone angle. It is interesting that the influence of agglomerated geometry-induced cavitation on spray cone angle was prominent. Furthermore, both the nozzle orifice L/D ratio and sac types have significant influences on string cavitation and spray characteristics. The smaller L/D ratio and VCO-type nozzles are prone to incur the stronger string cavitation, and then spray cone angle is obviously larger.

Synergistic effect of co-pyrolysis of macroalgae [Enteromorpha prolifera (EP)] and lignocellulosic biomass [rice husk (RH)] in a fixed bed reactor for maximum and enhanced biofuels yield has been investigated. The main and interaction effects of three effective co-pyrolysis parameters (pyrolysis temperature, feedstock blending ratio, and heating rate) were also modeled and simulated to determine the yield rates of bio-oil and bio-char, respectively. Optimization studies were, then, performed to predict the optimal conditions for maximum yields using the central composite circumscribed experimental design in Design Expert® software 8.0.6. Analysis of variance was carried out to determine whether the fit of the multiple regressions is significant for the second-order model. Normal pyrolysis oils from EP, RH, and co-pyrolysis oils obtained from different feedstock blending ratios were examined using the gas chromatography-mass spectrometry to identify their compositions. Some vital properties of oils and bio-chars such as the heating value, water content, elemental compositions, and specific gravity were also determined, which unveiled that synergistic effect exists between EP and RH during co-pyrolysis, and this led to increase in products’ yields and improved co-pyrolysis products’ quality.

Nowadays, microalgae are widely discussed as a promising feedstock for biofuel production. For higher crude bio-oil yield with good quality, microalgal biomass productivity and bio-oil characteristics are essential parameters. However, the same microalgal species has different chemical compositions at different growth phases. Therefore, the present study aimed to identify the best growth phase for high biomass productivity and optimal bio-oil production from the green microalga Micractinium conductrix via Py-GC/MS and TGA/MS analysis. M. conductrix was grown in a tubular photobioreactor and harvested at early exponential phase (EEP), middle exponential phase (MEP), late exponential phase (LEP) and stationary phase (STP). LEP showed the maximum significant (P ≤ 0.05) biomass productivity of 0.058 ± 0.004 g L−1 d-1, with maximum significant lipid and carbohydrate contents (28.7 ± 1.1 and 42.9 ± 1.2%dw, respectively). TGA/MS results confirmed that biomass harvested at MEP and LEP showed higher extent of conversion or mass loss reaction via thermal degradation with the lowest residual solid products. In addition, the hydrocarbon fragments in gaseous products (H2, C2H6, CH4, C2H4) from TGA/MS analysis were found to be released more abundantly at LEP. Moreover, Py-GC/MS results revealed that thermal decomposition of biomass harvested at LEP resulted in the highest significant relative contents of aliphatic hydrocarbons (41.2%) with lowest nitrogen-containing compounds (6.3%). The present study showed the significant impact of harvest time of microalgae on products characteristics of thermal decomposition and nominated LEP as the optimum growth phase to harvest M. conductrix for upgraded bio-oil production.

The present work aimed to study the heterogenous interaction between lignocellulosic bio-char and seaweeds volatiles during co-pyrolysis process using a sectional pyrolysis reactor. Enteromorpha clathrate (EN) and rice husk (HU) were selected as representatives for seaweeds and lignocelluloses, respectively. Physical and chemical properties of the interacted bio-char were studied. In addition, the produced bio-oil was characterized by gas chromatography mass spectrometer (GC/MS). After interaction with EN volatiles, the yield of interacted solid residue (HU + bio-char) increased in comparison with that of HU bio-char, with pronounced changes in C, N and H contents, suggesting deposition of some volatiles on the bio-char surface. FTIR analysis confirmed that the interaction between volatiles and the unstable highly active spots on the bio-char led to polycondensation reactions which resulted in more aromatic compounds. In addition, XPS spectra showed that the free radicals in EN volatiles play a significant role in removal of oxygen functional groups in HU bio-char. Furthermore, pore structure analysis and SEM confirmed that some micropores (

During pyrolysis process, hundreds of parallel and successive pyrolytic reactions between different constituents take place forming complex products. Understanding the pyrolysis behavior of each individual component as well as the interaction of different components is a challenge to further elucidate the complex biomass pyrolysis process. The present study aimed to explore the effect of celluloses (CE), as a main component of lignocellulosic biomass, on catalytic co-pyrolysis of Enteromorpha clathrata polysaccharides (ENP) and Sargassum fusiforme polysaccharides (SAP). The yields of bio-oil and non-condensable gas of pyrolyzed algal polysaccharides showed the lowest values, with the highest bio-char yield. However, co-pyrolysis of algal polysaccharides with CE enhanced the bio-oil yield of ENP and SAP by 34% and 29%, respectively, over the corresponding individual pyrolyzed polysaccharides. The results of GC–MS and FTIR of bio-oils confirmed the synergistic interaction between polysaccharides and CE during co-pyrolysis. Furthermore, bio-oils yields increased by 7.0% and 14.4% by catalytic co-pyrolysis of ENP + CE and SAP + CE, respectively. Interestingly, ZSM-5 resulted in significant reduction in acids and N-containing compounds of the produced bio-oil. In addition, ZSM-5 catalytic co-pyrolysis of the two studied polysaccharides with cellulose sharply increased furans and ketones proportions. The present results suggested catalytic co-pyrolysis as more favorable process for enhanced production of upgraded bio-oil.

Hydrogenated Catalytic Biodiesel (HCB), with excellent volatility and cetane number while without contain oxygen and aromatic hydrocarbons, have great potential to improve engine performance and emission characteristics. In this study, the effect of HCB/Diesel blended fuels properties (by mass fraction of biodiesel in diesel) on spray combustion characteristics was investigated at inert and reacting conditions in a constant volume combustion chamber. Laser (532 nm) Mie-scattering, OH∗ chemiluminescence and high-temperature luminosity were used to capture the spray liquid length, flame lift-off length and ignition delay simultaneously with the help of two intensifier charge coupled device cameras and a high speed Complementary Metal Oxide Semiconductor camera. Encouraging results were obtained at different ambient conditions (temperatures, densities, oxygen concentration) and injection pressures. The results showed that fuels with high cetane number generate shorter ignition delay, and faster auto-ignition results in a shorter flame lift-off length. A new theory was used to interpret the effect of cetane number on lift-off length. Under reacting conditions, the combustion heat release shorten spray liquid length apparently as compared with the results under inert conditions. The liquid length was slightly affected by the injection pressure and oxygen concentrations under both reacting and inert conditions, while the flame lift-off length is significantly influenced by ambient parameters and injection pressure.

In this article, optical experiments on string cavitation and residual bubbles inside the real-size transparent tapered diesel nozzle and near-nozzle spray structures were performed based on a high-pressure common rail fuel injection system with a high-speed camera. The tapered nozzle which has high flow efficiency with weak or even no geometric cavitation has been widely used in commercial injectors, while there still exists string cavitation which may also influence the in-nozzle flow and subsequent spray. This article put focus on the tapered nozzle and the result indicated that the in-nozzle string cavitation provided a reasonable explanation for the two bumps of spray cone angles during the opening and closing stages of needle of real diesel engine injection processes. The suction and compression of air bubbles at the start and end stages of injection processes, and the various shot-to-shot near-nozzle spray patterns were captured and analyzed. These different near-nozzle spray patterns were attributed to the distribution of residual bubbles inside the nozzle orifice. The residual bubbles were survived from the last injection or sucked into the nozzle during needle opening stages. Stagnant bubbles were compressed and then accelerated the residual fuel which was close to the injector tip, leading to the formation of mushrooms. This study confirmed that the initial mushroom and the tail were generated by the interactions between the residual/sucked bubbles and the residual/initial fuel, and the leading mushroom was incurred by the combination of the transverse expansion of the jet and the laminar layer theory. This work pointed out and analyzed the new sources of the cycle-to-cycle variation of air/fuel mixture and spray.

The coalescence of a pair of sub-holes forms a V-type intersecting hole for pressure atomizer nozzles. This design makes use of the internal impact effect to promote the breakup of liquid jets, enhancing liquid-gas mixing. To clarify the physical structure of the in- and near nozzle flow field for the V-type intersecting hole atomizer nozzles, high speed photography was employed to visualize the in-orifice and near field flow behaviors of four atomizer nozzles, three of which were V-type intersecting hole nozzles with impact angle varied from 30° to 50°, and the other one was a cylindrical hole nozzle as a reference. In-nozzle flow and jet images in both the intersecting plane and its axial normal plane were captured. The results show that the use of V-type intersecting holes in an atomizer nozzle eliminates the generation of cavitation inside the nozzle orifices even under the conditions of strong hydraulic flip for the reference nozzle, leading to 15%–50% higher discharge coefficients than those of the reference nozzle, and yields fan-shaped jets, which least and most disperse at the intersecting plane and its axial normal plane, respectively. Furthermore, these fan-shaped jets demonstrate superior radial dispersion, in terms of 1–5 times larger normalized cross sectional areas than those of the reference nozzle. Moreover, increasing the impact angle enhances the internal impact effect, resulting in wider spreading angles and larger cross sectional areas of the jets, however, lower discharge coefficients.

Biodiesel has the potential to replace the conventional diesel fuel, thus the increasing interest and research in the use of biodiesel fuels for transport applications to improve the emisions. In this work, the spray characteristics of diesel with hydrogenated catalytic biodiesel (HCB) fuel blends were investigated in a constant volume combustion chamber to provide an accessible tool to predict spray behavior based on cheap and off-engine condition measurements for applying HCB in diesel engines. As two important indexes of spray characteristics, the liquid penetration and vapor penetration were researched using Mie-scattering and Schlieren methods under non-reacting conditions to avoid the influence of combustion on the mixing and vaporization processes. Besides, the liquid length of blended fuel under reacting conditions is measured by a laser system to figure out the effect of combustion on atomization process. The results show that the liquid length decreases with increasing HCB ratio in the blends and the fuel density has greater influence on the liquid length than the fuel viscosity. By comparing the liquid length result, a slight difference between the different blends on vapor penetration was observed under the same boundary condition. The spray characteristics of blends indicate that HCB is a good blending component for blended fuel which can be applied in diesel engine directly in large-scale. Moreover, the liquid length of laser Mie-scattering method is higher than that of LED Mie-scattering and the liquid length under reacting conditions is shorter than that of inert conditions.

Biomass is a wide-spread resource that have been studied for decades to realize energy utilization is a renewable and sustainable way. It was reported that there is a synergistic interaction during co-pyrolysis of different biomasses such as algae and terrestrial plants, but the mechanism is still unclear. This study aims to investigate the heterogeneous interactions between rice husk (HU) volatile and Enteromorpha clathrate (EN) bio-coke during co-pyrolysis using a sectional tubular pyrolysis furnace. Physical and chemical properties of the interacted bio-coke were studied using N2 isothermal absorption method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In addition, the obtained bio-oil was also characterized by gas chromatography-mass spectrometer (GC/MS). The changes in specific surface area of the pyrolyzed bio-coke indicated the significant effect of HU volatiles on EN bio-coke microstructure. After flew through by rice husk volatiles, the adsorption capacity of EN bio-coke improved. Owing to the free radicals in HU volatile, polycondensation and aromatization reactions were enhanced in EN bio-coke resulting in aromatic compounds with higher cyclization of nitrogenous compounds. On the other hand, EN bio-coke participated the decomposition of carbohydrates in HU volatiles to increase the content of aldehydes and furans in the produced bio-oil. In addition, the significant Maillard reaction accelerated the production of ketones and phenols in the bio-oil and reduced the content of N in EN bio-coke at 400 °C. The present study confirmed that there is a significant interaction between seaweed bio-coke and rice husk volatiles during co-pyrolysis.

Catalytic co-pyrolysis process of Enteromorpha clathrata (EN) and rice husk (HU) was studied in a fixed bed reactor with ZSM-5 and MCM-41 catalysts at 550 °C. The yields and product distribution were compared when EN, HU and different mass ratios of EN and HU were pyrolyzed with or without catalysts. Bio-oil products were analyzed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry (GC–MS) and bio-char products were analyzed by X-ray photoelectron spectroscopy. Under co-pyrolysis conditions without catalysts, the experimental yield of bio-gas was higher than the theoretical. In contrast, the yield of bio-oil was lower than the theoretical. In the catalytic pyrolysis, ZSM-5 significantly improved the yield of bio-oil and reduced the bio-gas product. However, the effect of MCM-41 on the yield of the pyrolysis products was weaker than that of ZSM-5. In the GC–MS analysis of bio-oil with catalysts, ZSM-5 showed a catalytic effect on the decomposition of hemicellulose and protein. The protein was further cracked, and the relative content of hydrocarbon component also increased. With MCM-41 catalyst, there was significant catalytic effect on lignin and lipid, and the result showed that MCM-41 had a further catalytic influence in the synergetic effect of co-pyrolysis.

The pyrolysis characteristic of rice bran wax (RBW) and its bio-fuel oil were analyzed. TG, Py-GC-MS, TG-MS, FTIR, 1H NMR and 13C NMR were all carried out to analysis RBW pyrolysis characteristic and bio-fuel oil characteristic. TG results showed that RBW pyrolysis temperature was mainly in the temperature range of 350 °C–450 °C. The mean activation energy values calculated from KAS method and FWO method was 106.15 kJ/mol and 115.72 kJ/mol, respectively. The TG-MS results showed that main gas products were alkane and olefins. The Py-GC-MS also found the mainly components of pyrolysis products were alkane and alkene. The 1H NMR, 13C NMR and FTIR experiments were also carried out to confirm the component of bio-fuel oil. The results found that the main components of pyrolysis products were alkane and alkene. The bio-fuel oil properties were also analyzed. The acid value was very low. It was about 10 mg(KOH)/g. And the coke was found. The yield was about 8%. According to above results, it was confirmed that RBW maybe was a good bio-resource to obtain long carbon chain bio-fuel oil.

Hydrothermal liquefaction (HTL) of renewable microalgae is a potential promising technology for liquid biofuel production. This paper investigated the effect of ultrasonic pre-treatment of microalgae (Spirulina platensis) on HTL products distribution and oil quality. Cell disruption was enhanced with increasing of ultrasonic power and time. Liquefaction was promoted by larger ultrasonic power, but restrained by prolonged pre-processing time. Such promotion was found more pronounced at relatively lower liquefaction temperature. Combined with FT-IR, GC–MS and TG analysis, the ultrasonic pre-treatment increased the compounds at lower boiling point within the biocrude oil. The distillation characters of the hydrothermal oils were more near to the heavy Iraqi crude, with only 22 wt% in distillation zone of diesel.

The effects of the fuel temperature on diesel nozzle internal flow and the subsequent atomization were analyzed experimentally. Flow visualization was studied using a 10-times scaled-up transparent acrylic model nozzle with different geometries. A high-speed digital camera was used to capture the flow pattern in the region of the sac chamber and the nozzle. The energy loss in the occurrence of the hydraulic flip was also analyzed. In addition, cavitation images obtained in the multi-hole tapered nozzle with different fuel temperatures had revealed that although the conical shape of the converging tapered holes suppresses formation of geometry-induced cavitation, string cavitation has been clearly observed anyway. Afterward, the experimental method was used to analyze the effects of the nozzle sac volume structure on the cavitation flow inside the nozzle and subsequent spray. It was found that the in-nozzle flow stage and spray formation were sensitive to the fuel temperature. The visual experiment is helpful to understand the nozzle flow and optimize the diesel injectors eventually.

In this work, diffused back-illumination extinction imaging and OH* chemiluminescence imaging were employed simultaneously to measure the soot production, spray liquid length and flame lift-off length. These experiments were conducted in a high-temperature, high-pressure constant-volume combustion chamber equipped with a common-rail fuel injector with a single 180-μm-diameter orifice. Soot formation characteristics of a blend fuel (B50) with 50% hydrogenated catalytic biodiesel (HCB) and 50% 0# fossil diesel in mass were studied. Besides, the pure 0# fossil diesel (B0) under the same operating conditions was also measured as a reference. Parametric variations of injection pressure (100 MPa, 150 MPa), ambient temperature (770 K, 820 K, 870 K) and oxygen concentration (15%, 18%, 21%) have been performed for each fuel. After analysis, it was found both liquid length and flame lift-off length of B50 are shorter than that of B0. Soot onset time of B50 appears earlier and soot initial location is closer to the nozzle than that of B0. Within the measured optical access, soot area of B50 is larger than that of B0 because of shorter lift-off length, while the difference on total soot production is less noticeable because fuel properties of B0 is more favorable for soot formation.

In the present study, combustion of two seaweeds, Enteromorpha clathrate and Sargassum natans, was carried out in a bench-scale fluidized bed. According to the shrinking core model, combustion of E...

The production of bio-oil and bio-char by fast pyrolysis and hydrothermal liquefaction of Enteromorpha clathrata, rice husk and their mixtures have been compared. The results indicated that hydrothermal liquefaction produced higher yield of bio-oil and lower yield of bio-char for the same raw samples. There were more macromolecules (hexadecanoic acid, cyclopenten and esters), small-molecule hydrocarbons and N-containing compounds in hydrothermal liquefaction bio-oil, while more aromatic substances were observed in fast pyrolysis bio-oils. There was significant difference between E. clathrata bio-oils from these two thermochemical methods C O, CH/CH2/CH3 and N H functional groups in E. clathrata bio-oil from hydrothermal liquefaction showed stronger absorption strength than bio-oil from fast pyrolysis. However, the only difference between rice husk bio-oil from hydrothermal liquefaction and fast pyrolysis was aromatic ring signal in Fourier transform infrared spectroscopy curves. In addition, synergistic effect was investigated during the co-pyrolysis and co-hydrothermal processes. Such synergistic effect led to the improvement recorded in the bio-oil quality by deoxidation reaction to increase the H/C ratio in bio-oil from co-pyrolysis of E. clathrata/rice husk blends, and reduces the O/C ratio in bio-oil from co-hydrothermal process, and also enhances the calorie value of bio-oil. The synergistic effect, however, lowered the co-pyrolysis and co-hydrothermal bio-oils yields. Moreover, the addition of rice husk into E. clathrata promoted the bio-oil conversion efficiency of protein and increased the content of aromatic substances.

In this study, a pre-chamber was designed to form near stoichiometric mixture and provide multiple turbulent flame jets to ignite the lean mixture and accelerate the combustion in the main combustion chamber for a natural gas engine. A CFD simulation was employed to investigate the impact of the pre-chamber nozzle configurations on flow and combustion processes inside the engine, as well as on the performance of the engine. Various configurations were investigated, including orifice number of 4 to 8 and orifice diameter ranging from 1.6 m to 2.9 mm. A non-dimensional parameter, β, was used to characterize the relative flow area of these configurations. The numerical results indicate that, for a given nozzle flow area, among the design of different orifice numbers, the 6-orifice design can obtain the optimal combustion and engine performance. Otherwise, a design of more orifices leads to slower flame penetrating speed in the main-chamber, and the design of less orifices leads to slower circumferential flames propagations in the main-chamber. Moreover, for a 6-orifice pre-chamber, the optimal orifice diameter was found to be 2.0 mm, corresponding to a β value of 0.3. A design of larger diameters leads to slower penetrating for the flame jets and insufficient radial flame propagations in the main-chamber, while a design of relatively smaller orifice diameters leads to insufficient circumferential flames propagations in the main-chamber. Additionally, for the engine performance, all the pre-chamber designs improve the indicated efficiency and reduce the NOx emission. Especially, the design of 6-orifice with diameter of 2.0 mm achieves a 35.0% increase of indicated thermal efficiency and a 78.0% reduction of NOx emission compared to the prototype engine.

A 3D Eulerian-Lagrangian spray model coupled with the nozzle cavitating flow was proposed to simulate the atomization and secondary break-up. The nozzle flow and near-field spray were simulated with the Volume Of Fluid (VOF) multiphase model. At a certain downstream location, where the spray is diluted, the Eulerian spray approach was switched to the conventional Lagrangian approach. This entire methodology was validated through the experimental data of liquid spray penetration under non-evaporating chamber conditions. The numerical simulations based on multi-scheme were implemented by this model to investigate the effects of nozzle geometry and configuration on the subsequent spray development.

Renewable clean fuel such as biodiesel, alcohol-based fuel blended with fossil fuel has been widely studied for applications in engines aiming at partial solution of fuel consumption and environment emission issues. These blending fuels have also shown advantages in new combustion modes like GCI and LTC. However, the fuel injector nozzle internal flow and spray behaviors of these blending fuels are still not well understood, which may largely influence the subsequent fuel–air mixture, combustion, and emission characteristics. The investigation of cavitation flow in the high-pressure common-rail injector nozzle and spray characteristics with blending fuels of gasoline, diesel, and hydrogenated catalytic biodiesel (HCB) was conducted in the present work. The real-size optical nozzle was used to visualize the nozzle internal cavitating flow and spray. It was found that, by adding gasoline into diesel and HCB, the string cavitation increased significantly, and the spray cone angle expanded, especially under low needle lift. This behavior can be interpreted as the lower viscosity and higher saturation vapor pressure of gasoline enhanced vortex and cavitation. It can be concluded that increasing fuel temperature significantly impacted the cavitation and affected the vortex lightly, suggesting that with higher temperatures, blended fuels show better performance. As the fraction of HCB of gasoline/HCB blends increased, the cavitation inside nozzles was restrained due to its high viscosity. String cavitation can be interrupted by the needle tip, and the spray cone angle fluctuated enormously under this situation, which may cause uneven mixing of fuels and air.

In the present study, seaweed char-based catalyst was used for pyrolysis of waste clay oil to obtain high-grade biofuels. First, the biochar was activated at different temperatures of 600, 700, and 800 °C (Y600, Y700, and Y800, respectively). The specific surface area of seaweed char prepared by activation at 800 °C reached the maximum value (1227.74 m2/g), which was a good catalyst carrier. Then modified by Cu loading. Results showed that the seaweed carbon-based catalyst has a good decarboxylation effect. The obtained liquid product under catalytic pyrolysis showed the maximum heating value of 48402 kJ/kg by using 15% Cu/Y800 as a catalyst at feed/catalyst ratio of 10:1; with the highest hydrocarbon content, the content of long-chain hydrocarbons and aromatic hydrocarbons being 45.95% and 41.45%, respectively. The decarboxylation effect of Cu-modified seaweed char was obvious, and the copper particles distributed on the seaweed char form active sites, which effectively reformed the pyrolysis volatiles and promotes the production of hydrocarbons, especially aromatic hydrocarbons Therefore, the modified seaweed char-based catalyst has a certain aromatization effect. At the same time, the hydrogen content in the gas-phase product decreased significantly, which may be due to the hydrogenation reaction under the action of catalysis.

Hydrothermal liquefaction (HTL) is an effective conversion technology of microalgae biomass. In this study, the low-lipid microalgae-spirulina platensis was used as feedstock to investigate the performance of the biochar-based catalysts on HTL. The by-product of spirulina platensis HTL-solid residue was collected and activated to obtain the biochar (BC). Then, the BC was used as the carrier to support Co, Ni and their oxides CoOx and NiO to form Co/BC, Ni/BC, CoOx/BC, NiO/BC catalysts. The Response Surface Methodology (RSM) was used to optimize the HTL parameters and investigate the effect of biochar-based catalysts on HTL. The results showed that the maximum yield of bio-oil catalyzed by BC was 35.80 wt% with 304 °C, 34.7 min, and 0.32 g catalyst loading. BC catalyst displayed an improvement of bio-oil yield up to 4.00 wt% at low temperatures (260–280 °C). Ni/BC was the most favorable catalyst for bio-oil production, reaching a maximum value of 36.57 wt% at 280 °C, 35.0 min, and 0.15 g catalyst loading, which increased by 6.40 wt% compared with the non catalytic case. The characterization of bio-oil showed that CoOx/BC and NiO/BC could raise the hydrocarbon content, H/C value, and heat value, while decrease O/C value. Ni/BC had an excellent denitrification effect on bio-oil, the N content was reduced by nearly 2.00 wt% compared with the non catalytic case.

As a highly effective nanocomposite for hydrothermal liquefaction (HTL) of microalgae, the recycled biochar synthesized from Spirulina platensis and impregnated into CeO2 has been demonstrated. The order of in situ > ex situ > biochar nanocomposites for higher bio-oil. The highest bio-oil conversion of 33% was achieved at the optimum temperature of 250 °C. The use of the biochar nanocomposite also resulted in a decrease in the oxygen and nitrogen content of the bio-oil and an increase in its heating value, which was found to be high at 35.64 MJ/kg. With the inclusion of the in situ biochar nanocomposite, energy recovery was increased by up to 65.34%. The current study has shown that low biochar nanocomposite concentrations (0.20 g), low temperature (250 °C), and short residence time (30 min) are essential for improved bio-oil yield and quality of bio-oil.

Methanol is considered a favorable renewable fuel for use in diesel engines owing to its advantageous features including sustainability, accessibility, and reasonable price. However, some drawbacks, such as the phase separation problem, low cetane number, and high latent heat of vaporization, hinder its utilization in diesel engines. This study attempted to improve the usability of methanol in diesel engines using n-octanol and diethyl ether as cosolvents and ignition improvers. The experimental part was divided into two stages. First, the stabilities of pure methanol and hydrous methanol, with waste cooking oil biodiesel as a base fuel, were investigated under different temperatures: 10 °C, 20 °C, and 30 °C. The results demonstrated that the pure methanol/waste cooking oil biodiesel mixtures remained stable at all temperatures. To improve the solubility of the hydrous methanol/waste cooking oil biodiesel blends, n-octanol was applied as a cosolvent. Next, the engine combustion and emission features were assessed using three ratios of pure methanol/waste cooking oil biodiesel blends with n-octanol and diethyl ether additives. The three combinations included 15%, 25%, and 35% methanol with 10% n-octanol and 2.5% diethyl ether. The waste cooking oil biodiesel was produced via the transesterification method, and the final product was characterized using Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry, and thermogravimetric analysis. The fuels were evaluated via thermogravimetric analysis, and their physicochemical properties were determined according to the American Society for Testing and Materials standards. The highest cylinder pressure, heat release rate, and pressure rise rate were lower for the methanol/waste cooking oil biodiesel/n-octanol/ diethyl ether blends compared with the waste cooking oil biodiesel. In addition, the thermal efficiency reduced, while the brake specific fuel consumption increased for the mixtures compared with the waste cooking oil biodiesel. Relative to engine emissions, the nitrogen oxide levels also reduced, while the carbon monoxide and smoke opacity increased for the combinations compared with the waste cooking oil biodiesel.

Methanol has been considered as a promising alternative fuel for combustion engines. However, it is quite challenging to use it directly in compressed ignition engines because of its ignition issues, especially for low load conditions. In this research, methanol was blended with hydrogenated catalytic biodiesel (HCB) using n-octanol as co-solvent. A fundamental study on spray and combustion characteristics of two ternary blends (68% HCB+17% octanol+ 15% methanol by volume; 58% HCB+17% octanol+ 25% methanol by volume) and the pure HCB was carried out within a constant volume combustion chamber equipped with a single-hole injector. As in Part Ⅰ, the spray morphology, ignition delay, and flame lift-off length have been studied in detail. This part focuses on liquid length and in-flame soot formation of reacting sprays, which were quantified utilizing a diffused back-illumination extinction imaging technique. There is an overlapping area between the fuel liquid phase and flame for all three fuels under all operating points. The reduction on liquid length after ignition is more noticeable for pure HCB than other blends, because of its shorter lift-off length. The results show that the liquid length increases with increasing fraction of methanol in the mixtures, which is mainly governed by the high latent heat of vaporization of methanol. Furthermore, extra methanol addition brings a considerable reduction on in-flame soot production because of the leaner fuel combustion at longer flame lift-off length, as well as the more oxygen content within the blends.

s The super high fuel injection pressure and micro size of nozzle orifice has been an important development trend for the fuel injection system. Accordingly, cavitation transient process, fuel compressibility, amount of non-condensable gas in the fuel and cavitation erosion have attracted more attention. Based on the fact of cavitation in itself is a kind of thermodynamic phase change process, this paper takes the perspective of the cavitation phase change mass transfer process to analyze above mentioned phenomenon. The two-phase cavitating turbulent flow simulations with VOF approach coupled with HRM cavitation model and U-RANS of standard k-e turbulence model were performed for investigations of cavitation phase change mass transfer process. It is concluded the mass transfer time scale coefficient in the Homogenous Relaxation Model (HRM) representing mass transfer rate should tend to be as small as possible in a condition that ensured the solver stable. At very fast mass transfer rate, the phase change occurs at very thin interface between liquid and vapor phase and condensation occurs more focused and then will contribute predictably to a more serious cavitation erosion. Both the initial non-condensable gas in fuel and the fuel compressibility can accelerate the cavitation mass transfer process.

Bubbles surviving from the last injection process play an important role in the early stage of the next injection process, and ultimately affect the quality of diesel spray characteristics. In this paper, a combination of the LES (Large Eddy Simulation) method and VOF (Volume of Fluid) model was applied to study the unsteady liquid jet flow at the early stage of injection coupling the cavitating flow inside orifices, especially to analyze the effects of the residual bubble on the diesel jet. It was found that the instability of the jet surface was intensified by the cavitating flow inside the nozzle. The development of jet instability waves and the cavitation collapse inside the jet aggravated the interactions between air and diesel jet, which caused the liquid core to separate into some large liquid bulks a bit earlier. Then, the ligaments formed from the bulks broke up into droplets. Furthermore, the double mushroom-like shape occurred with the residual bubble, while just a single mushroom head occurred without the residual bubble. The length of liquid core decreased with the increasing of injection pressure, and the phenomenon that the air inside the spray chamber was partly sucked into orifice was observed.

Pyrolysis characteristic of hydrogenated palm oil (HPO) was analyzed using TG, TG-FTIR-MS and Py-GC-MS. Bio-fuel oil (BFO) was obtained using catalytic cracking method. The BFO was analyzed by FTIR, 1 H NMR, 13 C NMR, GC-MS and ESI FT-ICR MS to provide complementary and comprehensive adequate information. TG-DTG results showed that the HPO pyrolysis was different with other plant oil. It was clear that HPO pyrolysis was mainly in temperature range of 350 °C–500 °C. The mean activation energy of HPO pyrolysis calculated from KAS and FWO models was 161.10 kJ/mol and 164.28 kJ/mol, respectively. According to TG-FTIR-MS results, little amount of gas components was detected. Py-GC-MS result found heavy compounds, which carbon number exceeds 18. FTIR, 1 H NMR, 13 C NMR and GC-MS results found the BFO mainly contained long-chain alkane and alkene. According to ESI FT-ICR MS, the oxygen containing compounds in BFO were from O 2 O 6 classes, with the O 2 being the major class. The RSFTIR was first used to analyze biomass pyrolysis. The results found that in the decarboxylation process, the carbon chain also was cracked to form short carbon chain carboxyl firstly. According to above experiments results, we can confirm HPO pyrolysis path was different with palm oil. The key conclusion was that HPO maybe was a good bio-resource to obtain BFO, and it was mainly contained diesel-like components. Compared to palm oil pyrolysis products, HPO pyrolysis products were mainly contained long-chain alkane and alkene. The recommended pyrolysis path was also proposed.

In this work, the direct liquefaction (DL) of low-lipid microalgae Spirulina was investigated in a 50 ml autoclave reactor with ethanol and water as co-solvent. The objective of this research was carried out to examine the effect of operating conditions such as reaction temperature, reaction time, solvent/microalgae (S/M) ratio and ethanol-water co-solvent (EWCS) composition on product distribution and bio-oil characterization. The results revealed that the optimal operating conditions for bio-oil yield and conversion rate were reaction temperature of 300 °C, reaction time of 45 min, ethanol content of 50 vol.% and S/M ratio of 40/4 ml/g, which gave the bio-oil yield of 59.5% and conversion rate of 94.73%. Conversion rate in EWCS was significantly higher than that in pure water or ethanol, suggesting the synergistic effect between ethanol and water during microalgae DL. Distinct difference in composition and relative content of compound among bio-oils in different solvents were observed by GC–MS and FT-IR. Compared with hydrothermal liquefaction, the most abundant compounds in bio-oil from both EWCS and pure ethanol were esters. The presence of ethanol could enhance the bio-oil yield and improve bio-oil quality by promoting the formation of esters.

A V-type intersecting hole nozzle, in which each hole is formed by the coalescence of a pair of sub-holes, has been developed to improve fuel-air mixing for diesel engines. In this paper, a numerical study has been conducted to examine the effects of the V-type intersecting hole structure on the internal flow of a nozzle and the initial stage of the fuel-air mixing processes. With this aim, a multi-phase flow calculation has been implemented on seven V-type intersecting hole nozzles with impact angles ranging from 20° to 50° and a referenced cylindrical hole nozzle under injection pressures varying from 60 MPa to 240 MPa. The comparison was made in terms of mass flow, momentum flux, effective velocity, discharge coefficient, area coefficient and velocity coefficient. The three-fluid model, which was validated using X-ray experimental data of an Engine Combustion Network (ECN) Spray A injector, was employed to calculate the associated multi-phase flow. The main results show that use of a V-type intersecting hole in a nozzle eliminates cavitation, leading to higher mass flow and momentum flux. Correspondingly, for these V-type intersecting hole nozzles, the discharge coefficients are insensitive to injection pressure, but decrease with an increasing impact angle, and are 20–30% higher than those of the cylindrical hole nozzle. These higher discharge coefficients mainly result from very high area coefficients that are approximately 0.98 at all injection pressure conditions because of the non-cavitating nature of the in-nozzle flow. Moreover, the impact effect of a V-type intersecting hole results in a fan-shaped jet with a very large spreading angle (25–40°) at the dispersion plane and a relatively narrower angle (approximately 12°) at the impact plane. The jet spreading angles at both planes are wider than that of the cylindrical hole nozzle (approximately 7°), indicating a noticeable improvement in the initial fuel-air mixing. Additionally, an increase in the impact angle of a V-type intersecting hole nozzle promotes initial mixing in terms of yielding a wider jet spreading angle, in spite of a slightly lower effective velocity.

Effects of Injection rates on combustion process and emissions of engines operating with directly injected natural gas and pilot diesel were numerically investigated. Injection rates of natural gas and diesel were investigated separately utilizing five types of injection rates. An impact factor was defined to present the effects of the initial and terminal injection rates of diesel and natural gas on the combustion and emissions more intuitionally. Based on the simulation results, cylinder pressure and temperature were more sensitive to terminal injection rates of pilot diesel than initial injection rates, and lower terminal injection rates of pilot diesel can achieve lower NO and Soot emission level. However, there is a trade-off between NO and Soot emissions affected by different natural gas injection rates. The impact factors of pilot diesel injection rates on pressure show a double-peak trend. However, the impact factors of natural gas injection rates on pressure show a single-peak trend.

The pyrolysis mechanisms of typical seaweed polysaccharides were investigated using TG-MS and Py-GC/MS. It was found that Enteromorpha polysaccharides (EN) was mainly composed of glucan, xylan and glucuronide-sulfate-rhamnose, while Sargassum fusiforme (SA) mainly consisted of uronic acid, sulfate group-fucose and polysaccharide galactose. Because of the component differences, it was found that the content of oxygen-containing functional groups and inorganic oxides varies. Meanwhile, three types of sulfur-containing functional groups (sulfonyl groups, sulphates, sulfate) were observed in seaweed polysaccharide. During the pyrolysis process, SO 2 was generated because of the cleavage of sulfuric acid group in 4- O -glucuronide-2 sulfate- l -rhamnose. The generation of CO 2 was due to the decarboxylation of organic matter. Besides, Py-GC/MS analysis indicated that the main pyrolysis products of EN polysaccharides were furans. The pyrolysis products of SA polysaccharides were mainly ester substances. Thus, the pyrolysis mechanisms as well as the generation pathways of main products of polysaccharides pyrolysis, were revealed.

Co-pyrolysis conversion of seaweed (Enteromorpha clathrat and Sargassum fusiforme) polysaccharides and cellulose has been investigated. From the Py-GC/MS results, Enteromorpha clathrata (EN) polysaccharides pyrolysis mainly forms furans; while the products of Sargassum fusiforme (SA) polysaccharides pyrolysis are mainly acid esters. The formation mechanisms of H2O, CO2, and SO2 during the pyrolysis of seaweed polysaccharides were analyzed using the thermogravimetric-mass spectrometry. Meanwhile the pyrolysis of seaweed polysaccharide based on the Amber and the ReaxFF force fields, has also been proposed and simulated respectively. The simulation results coincided with the experimental results. During the fast pyrolysis, strong synergistic effects among cellulose and seaweed polysaccharide molecules have been simulated. By comparing the experimental and simulation value, it has been found that co-pyrolysis could increase the number of molecular fragments, increase the pyrolysis conversion rate, and increase gas production rate at the middle temperature range.

Increasing the injection pressure and downsizing the nozzle orifice diameter have been major measures for diesel engines to facilitate fuel–ambient gas mixture formation and combustion processes. The objective of this investigation is to carry out a quantitative analysis on the effects of micro-hole nozzle and ultra-high injection pressure on the mixing and combustion characteristics of diesel spray flame. Hence, laser-induced fluorescence and particle image velocimetry technique was employed to quantitatively access the gas entrainment of diesel spray emerging from nozzle with orifice diameter down to 80 µm under injection pressure up to 300 MPa, together with OH* chemiluminescence imaging and two-color pyrometry techniques to resolve the combustion and soot formation processes. Additionally, numerical simulation on the multi-phase flow inside injector nozzle was conducted to obtain information on internal flow dynamics. Experimental results show that over 80% of the ambient gas entrained into a spray pl...

Simultaneous imaging of OH ∗ chemiluminescence and Mie scattering of fuel spray have been performed under reacting conditions in a constant volume combustion chamber aimed for a second-generation biodiesel/diesel blended fuel. Mie scattering of 532 nm laser light technique was used for the liquid fuel measurement. In order to remove the interference signal from soot radial, filtered Mie scattered light from the fuel droplet was recorded with a charge coupled device (CCD) camera. The spray liquid length and the flame lift-off length for this high cetane-number fuel were investigated under different ambient gas conditions (temperature, density, oxygen concentration) and injection pressure. Experiments showed that the spray liquid length under the reacting condition was shorter than that under non-reacting condition. The flame lift-off length was significantly influenced by the ambient gas temperature, density, oxygen concentration and injection pressure, while the spray liquid length was slightly affected by the injection pressure and oxygen concentration. The overlap between liquid fuel and combustion flame easily happened at high temperature, high oxygen concentration, and low injection pressure conditions.

The reactivity of dolomite, limestone and NiO/Dolomite toward hydrogen production during high temperature steam gasification of biomass were evaluated. NiO/Dolomite additive was prepared from impregnation of NiO on dolomite surface. Reactor with gasification bed operated at 900 °C and sorption/reforming bed operated at 730 °C at downstream was applied in this paper. Results show that co-gasification of biomass and additive increased overall gas yield and also the CO 2 concentration. With dolomite in the sorption/reforming bed and none additive in gasification bed, the highest hydrogen concentration was achieved (71.8 vol.%). With 2wt.% NiO/Dolomite in the sorption/reforming bed and dolomite in the gasification bed separately, the highest hydrogen yield (510 cm 3 /g) was reached. Further increasing NiO content decreased hydrogen yield, sorption capacity and increased coke deposition. Calcination of NiO/Dolomite at 950 °C led to formation of NiO MgO phase and reduced to Ni MgO phase during gasification which increased the catalysis of the additive.