Comparison of lumped and molecular modeling of hydropyrolysis

Liguras, Dimitris K.; Allen, David T.

doi:10.1021/ie00001a007

Cited by 34 publications

(15 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As regards species lumping method, the critical issue is determining which species to lump, classifying the contribution of each selected species to the lumped ones, and estimating their kinetic parameters (Stagni et al, 2013). In the chemical lumping method, species are lumped according to their chemical structure (Liguras and Allen, 1992), while mathematically based approaches rely on formal transformation rules between original and lumped variables (Pinto et al, 1999). The first approach requires wide chemical expertise, e.g., at high temperatures, FIGURE 9 | Experimental (symbols)-numerical (lines) comparison of ignition delay times for n-butanol/air mixture: (A) Pressure = 15 bar, equivalence ratio = 0.5 (spheres), 1.0 (squares), 2.0 (triangles), (B) equivalence ratio=1.0, P = 10 atm (spheres), P = 20 atm (squares), P = 40 atm (triangles).…”

Section: Development Of a Reduced Chemical Mechanism For Combustion Omentioning

confidence: 99%

Biofuel Powering of Internal Combustion Engines: Production Routes, Effect on Performance and CFD Modeling of Combustion

Costa

Piazzullo

2018

Front. Mech. Eng.

View full text Add to dashboard Cite

The use of liquid or gaseous biofuels in reciprocating internal combustion engines (ICEs) is today a relevant issue as these systems are largely diffused for both steady power generation and transportation due to their flexibility and easiness of use. The improvement and perfect control of the combustion process under non-conventional fueling is mandatory to achieve high-energy efficiency without substantial changes to the architecture or the fuel supply system. In this perspective, the detailed characterization of multiphase reacting systems achievable though computational fluid dynamics (CFD) may give a decisive contribution. However, the assessed combustion models used for fossil fuels (diesel oil, gasoline, methane), tuned on the ground of a massive amount of experimental data, often results poor in predicting the actual behavior of renewable fuels whose composition and properties may change also according to technology for their production. Present work aims at filling some existing gaps in biofuel combustion modeling by performing investigations on two representative engine cases, for their characterization and performance enhancement. Two approaches are followed, namely through reduced chemical kinetics coupled with turbulence within a coherent flame schematization, and through a turbulent species transport approach with detailed kinetics. Simulations are first carried out on a compression ignition (CI) ICE. The formulation of a 3D CFD model is described to reproduce the performance of this engine in a dual-fuel mode with premixed syngas from biomass gasification and a biodiesel pilot injection leading to self-ignition. Pollutants formation and energy efficiency are calculated as syngas amount and the biodiesel start of injection (SOI) are varied. Attention is then focused on the implementation of renewable alcohol fuels (ethanol and butanol), as these lasts are receiving large interest due to low production costs. A validated reduced kinetic mechanism for PRF-ethanol-butanol combustion performs well in multi-component oxidation conditions, as well as in neat fuel oxidation conditions, in terms of ignition delay time, laminar flame speed and HCCI combustion conditions. The paper shows that CFD, even at different level of approximation, may describe into detail the combustion process and provide important guidelines for the design of new generation ICEs fuelled by biofuels.

show abstract

Section: Development Of a Reduced Chemical Mechanism For Combustion Omentioning

confidence: 99%

Biofuel Powering of Internal Combustion Engines: Production Routes, Effect on Performance and CFD Modeling of Combustion

Costa

Piazzullo

2018

Front. Mech. Eng.

View full text Add to dashboard Cite

show abstract

“…However, many reactions consist of more than one reactant, which complicates depiction by this method. Sandefur et al gave a series of graph methods to depict complex reactions …”

Section: The Tools and Their Integrationmentioning

confidence: 99%

Integrating Visualization Methods with Chemical Kinetics Model Solution and Editing Tools

Lucio-Vega

Zhang

et al. 2017

Energy Fuels

View full text Add to dashboard Cite

We developed a set of tools for visualizing, analyzing, and editing reaction networks. Three conceptual elements were covered. In the first, the reaction network was rendered in terms of species−species and species−reaction tree plots. This provided for a visual inspection of the connectivity of components in a reaction network and the paths from reactants to products. More quantitative information was provided by the second element, which represented the quantitative concentration of the composition as it evolved from reactants to products. This allowed the modeler to examine the quantitative flows of mass though the reaction network and expose flaws for editing. The third element involved a coupling of the tree visualization and model solution tools that allowed for the elimination of reactions and rebuilding of the reaction network from the visualization interface. These tools are illustrated using the production of butadiene through catalytic oxidative dehydrogenation of butane as an example.

show abstract

“…Jiao et al and Jia et al established detailed mechanisms for n -decane thermal cracking, and Dahm et al and Herbinet et al showed the detailed mechanisms for n -dodecane. Detailed models are important in chemistry, but they require a large number of computations when used in computational fluid dynamics (CFD) simulations, which makes these models difficult to use for engineering purposes. , …”

Section: Introductionmentioning

confidence: 99%

Differential Global Reaction Model with Variable Stoichiometric Coefficients for Thermal Cracking of n-Decane at Supercritical Pressures

2019

View full text Add to dashboard Cite

This study presents a new modeling approach for the thermal cracking of hydrocarbon fuels at supercritical pressures. The thermal cracking process is treated as an infinite number of continuous microreactions at different fuel conversions, in which the stoichiometric coefficients of each species are expressed by continuous differentiable functions of the fuel conversion to consider the effects of secondary reactions. A set of thermal cracking experimental results involving n-decane was used as an example to show how to establish the differential global reaction (DGR) model with variable stoichiometric coefficients. The DGR model was implemented in a computational fluid dynamics simulation to predict n-decane thermal cracking coupled with flow, heat transfer, and wall thermal conduction. The results showed that the DGR model can more accurately predict the species mass fractions than existing global reaction models, especially for conditions when the secondary reactions strongly impact the thermal cracking. The root-mean-square error (RMSE) of the predicted mass fractions of all species was 4.2% relative to the experimental data for a conversion of 24.2%, while the RMSE was 61.1% for an existing global reaction model. The DGR model is a modified global reaction model; thus, it is computationally efficient. The stoichiometric coefficients of the DGR model determined from the thermal cracking experiments only require the species mass/molar fractions; therefore, the modeling method can be easily extended to other hydrocarbon fuels.

show abstract

Comparison of lumped and molecular modeling of hydropyrolysis

Cited by 34 publications

References 12 publications

Biofuel Powering of Internal Combustion Engines: Production Routes, Effect on Performance and CFD Modeling of Combustion

Biofuel Powering of Internal Combustion Engines: Production Routes, Effect on Performance and CFD Modeling of Combustion

Integrating Visualization Methods with Chemical Kinetics Model Solution and Editing Tools

Differential Global Reaction Model with Variable Stoichiometric Coefficients for Thermal Cracking of n-Decane at Supercritical Pressures

Contact Info

Product

Resources

About