Fuel

Journal: Fuel

Publisher

Elsevier

ISSN

0016-2361

Show all metadata

Search Results

Publications 1 - 10 of 63

Phenomenological micro-pilot ignition model for medium-speed dual-fuel engines
Park, Hyunchun; Wright, Yuri M.; Seddik, Omar; et al. (2021)
Fuel
The medium-speed dual-fuel engine has become popular in the marine industry for its advantages of fulfilling the stringent emission regulations and relative affordability of natural gas. In such engines, the ignition process importantly influences the subsequent combustion processes and engine performance. This work developed a phenomenological micro-pilot ignition model with a minimal number of tuning parameters aiming to improve the understanding of the ignition event and enable better control of the dual-fuel engine. The model comprises of a spray and a chemistry submodel to accurately capture the interaction between the direct injection of a small amount of diesel fuel (called micro-pilot) and a two-stage ignition of the diesel fuel mixed with the surrounding reactive charge in relatively low temperature. A 1D transient spray model is adapted to reproduce the micro-pilot spray characteristics by assuming a realistic trapezoidal fuel injection profile and the varying discharge coefficient during the transient spray period. The chemical reactions are modeled with a 0D transient flamelet approach based on an opposed flow reactor. The model is validated using three sets of experimental data, namely ECN Spray A (constant volume chamber), RCEM with optical accessibility, and finally, medium-speed dual-fuel engine. Quantitatively good predictions of the spray formation, ignition delay, and ignition location over broad conditions ranging from the conventional diesel ignition to the micro-pilot ignition in the dual-fuel engine are demonstrated. Finally, the developed model is used to explore the characteristics of micro-pilot ignition under conditions relevant to the medium-speed dual-fuel engines.
Hydrocracking of hexadecane to jet fuel components over hierarchical Ru-modified faujasite zeolite
Azkaar, Muhammad; Vajglová, Zuzana; Mäki-Arvela, Päivi; et al. (2020)
Fuel
Hexadecane hydrocracking was investigated over bifunctional Ru-containing micro- and mesoporous USY zeolites at 250 degrees C under 45 bar in the presence of hydrogen in a batch reactor. A comparative study was performed using the Ru-free zeolites in the protonic form. The highest yield of jet-fuel products, C-9 - C-15, being 26% at 71% conversion, was obtained with 2.5 wt% Ru deposited on a hierarchical micro-mesoporous USY zeolite, e.g. a material possessing secondary porosity, where a superior combination of acidity and mesoporosity was created by treatment of the parent zeolite with aqueous sodium hydroxide and tetrapropylammonium hydroxide.
Reaction kinetics of the combined pyrolysis and steam-gasification of carbonaceous waste materials
Piatkowski, Nicolas; Steinfeld, Aldo (2010)
Fuel
Sol-gel-derived, CaO-based, ZrO2-stabilized CO2 sorbents
Broda, Marcin; Müller, Christoph R. (2014)
Fuel
A two-zone solar-driven gasifier concept
Kruesi, M.; Jovanovic, Z.R.; Steinfeld, Aldo (2014)
Fuel
Compensation for the differences in LHV of diesel-OME blends by using injector nozzles with different number of holes: Emissions and combustion
Parravicini, Matteo; Barro, Christophe; Boulouchos, Konstantinos (2020)
Fuel
Relative permeability of gas and water flow in hydrate-bearing porous media: A micro-scale study by lattice Boltzmann simulation
Ji, Yunkai; Kneafsey, Timothy J.; Hou, Jian; et al. (2022)
Fuel
The water-gas relative permeability is an important parameter to characterize multiphase flow in sediments. To study the water-gas relative permeability of hydrate-bearing porous media, multiphase flow simulations were carried out at the pore scale using the lattice Boltzmann method. The effects of hydrate saturation and hydrate-growth habits on the water-gas relative permeability, which is scaled by the relative permeability considering the hydrate only, were evaluated in a two-dimensional porous medium. Results show that the increase of hydrate saturation causes the decrease of water-gas effective permeability as expected. However, the effect of hydrate saturation on the water-gas relative permeability is different from that of hydrate saturation on the water-gas effective permeability. The water-gas relative permeability increases with the increase of hydrate saturation in the pore-filling case. The water-gas relative permeability decreases with the increase of hydrate saturation in the grain-coating case. The wettability of solid phase has a different effect on the relative permeability of wetting phase and nonwetting phase. The Jamin effect (phase blocking) was observed and may exist in the production of gas from natural gas hydrate reservoirs. This seriously affects the multiphase flow characteristics. The changes of microscale fluid distribution effect the changes of water-gas relative permeability. The relationship between the water-gas relative permeability and the characterization parameters of microscale fluid distribution was analyzed.
Experimental characterization of GTL, HVO, and OME based alternative fuels for diesel engines
Parravicini, Matteo; Barro, Christophe; Boulouchos, Konstantinos (2021)
Fuel
A promising way to reduce the environmental impact of compression ignition engines is represented by alternative fuels. These can be advantageous regarding both CO2 intensity and/or because of favourable combustion and emission characteristics. In the present study, eight fuels were tested experimentally. Conventional diesel was used as reference fuel. GTL and HVO were tested neat and blended with diesel at 20 vol%. 7 vol% and 15 vol% OME in diesel were tested as well. Finally a blend of 18 vol% OME in HVO was also investigated. This last blend, called R100, represents a potentially fully renewable fuel compliant with the EN590 standard regarding viscosity and density. The combustion and emissions behaviour of the test fuels were investigated in order to find distinguishing features. All the alternative fuels improve the emissions of soot and NOx. Oxygenated fuels were found to mix faster with air while the behaviour of the paraffinic fuels depends on their molecular length. © 2021 Elsevier
Screening and design of active metals on dendritic mesoporous Ce0.3Zr0.7O2 for efficient CO2 hydrogenation to methanol
Alabsi, Mohnnad H.; Wang, Xilong; Zheng, Peng; et al. (2022)
Fuel
Different active metals (PdCu, PdZn, CuZn, CuGa, and CuNi) over novel dendritic Ce0.3Zr0.7O2 (CZ) support were optimized to investigate their metal alloy interactions and further utilize their surface properties of the spherical morphology and the open pores of the dendritic support. The nature of the dendritic support offers a distinctive property in which it can increases the distribution of active sites. This variety of bimetallic phases withhold a distinctive interaction characteristic with the support that could promote CO2 hydrogenation to methanol by improving the oxygen vacancies and modifying the catalyst's reduction property. The addition of ZnO species into PdZn/CZ catalyst and the higher dispersion degrees of active metals could generate more oxygen vacancies that can improve and stabilize the methoxy species and promote the formate routes, thus, improve the activity of CO2 hydrogenation to methanol reaction. PdZn/CZ catalyst displayed the highest CO2 conversions (25.7 %), methanol yield (6.9 %), and superior 100 h long-term stability than those of other bimetallic catalysts. The best CO2 hydrogenation activity of the PdZn/CZ catalyst can be ascribed to the CO2 adsorption capabilities of CZ support that generated added oxygen vacancies and hydrogen dissociation performance of the Pd-ZnO active site.
Comparative analysis on the performance of pressure and air-assisted urea injection for selective catalytic reduction of NOx
Spiteri, Alexander; Eggenschwiler, Panayotis D.; Liao, Yujun; et al. (2015)
Fuel

Publications 1 - 10 of 63

Journal: Fuel

Abbreviation

Publisher

Journal Volumes

ISSN

Description

Filters

Search Results