When will fossil fuel reserves be diminished

Catalytic partial oxidation of methane has been reviewed with an emphasis on the reaction mechanisms over transition metal catalysts. The thermodynamics and aspects related to heat and mass transport is also evaluated, and an extensive table on research contributions to methane partial oxidation over transition metal catalysts in the literature is provided. Presented are both theoretical and experimental evidence pointing to inherent differences in the reaction mechanism over transition metals. These differences are related to methane dissociation, binding site preferences, the stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species. Methane dissociation requires a reduced metal surface, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H, H2, C or CO. The comparison of elementary reaction steps on Pt and Rh illustrates that a key factor to produce hydrogen as a primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O–H, OH–H and CO–O interactions are reduced. The local concentrations of reactants and products change rapidly through the catalyst bed. This influences the reaction mechanisms, but the product composition is typically close to equilibrated at the bed exit temperature.

A review of catalytic partial oxidation of methane to synthesis gas with emphasis on reaction mechanisms over transition metal catalysts

Microscale combustion: Technology development and fundamental research

The microscopic spatial kinetic Monte Carlo (KMC) method has been employed extensively in materials modeling. In this review paper, we focus on different traditional and multiscale KMC algorithms, challenges associated with their implementation, and methods developed to overcome these challenges. In the first part of the paper, we compare the implementation and computational cost of the null-event and rejection-free microscopic KMC algorithms. A firmer and more general foundation of the null-event KMC algorithm is presented. Statistical equivalence between the null-event and rejection-free KMC algorithms is also demonstrated. Implementation and efficiency of various search and update algorithms, which are at the heart of all spatial KMC simulations, are outlined and compared via numerical examples. In the second half of the paper, we review various spatial and temporal multiscale KMC methods, namely, the coarse-grained Monte Carlo (CGMC), the stochastic singular perturbation approximation, and the τ-leap methods, introduced recently to overcome the disparity of length and time scales and the one-at-a time execution of events. The concepts of the CGMC and the τ-leap methods, stochastic closures, multigrid methods, error associated with coarse-graining, a posteriori error estimates for generating spatially adaptive coarse-grained lattices, and computational speed-up upon coarse-graining are illustrated through simple examples from crystal growth, defect dynamics, adsorption–desorption, surface diffusion, and phase transitions.

/pdf/an-overview-of-spatial-microscopic-and-accelerated-kinetic-4sih54fo7m.pdf

An overview of spatial microscopic and accelerated kinetic Monte Carlo methods

Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane/air mixtures

Kinetics of dimerization of isobutylene in the presence of ion exchange resin

This paper proposes the use of Computational Fluid Dynamics (CFD) techniques as an instructional tool for the topic of flow non-idealities in Chemical Reactors. The residence time distribution (RTD) and velocity contours obtained from CFD simulations will enable visualisation of crucial reactor flow patterns. The tool is expected to augment conventional teaching of the undergraduate course on Chemical Reaction Engineering.

CFD - A virtual platform for teaching concepts in non-ideal Chemical Reactors

Ag/γ-Al2O3 is an effective catalyst for the selective reduction of NOx (SCR) using propylene as a reducing agent. The catalyst performance is greatly influenced by the synthesis procedure. Various methods for synthesis of Ag/γ-Al2O3 are analyzed, and their performance is examined via packed bed reactor experiments in this work. An optimal one-pot synthesis method, single-step sol–gel (SSG) synthesis, is explored systematically. The SSG-synthesized catalyst shows better performance than those prepared via wet impregnation. The influence of synthesis conditions, specifically pH, on the textural and morphological properties of the SSG-synthesized Ag/γ-Al2O3, and therefore the activity for hydrocarbon-based SCR in a packed-bed reactor, are analyzed using experiments and simulations. The optimized catalyst demonstrates excellent performance (90% NOx conversion) for NOx reduction under nominal operating conditions with a wide activity temperature window (300–600°C). The catalyst shows good time-on-stream performance and is effective at higher inlet oxygen concentrations and space velocities. A global kinetic model, which uses synthesis-pH-dependent parameters, is proposed, and its ability to predict the activities of these catalysts is validated. 

Optimizing the synthesis of Ag/
 <scp>
 γ‐Al
 2
 O
 3
 </scp>
 for selective reduction of
 <scp>NOx</scp>
 with
 <scp>
 C
 3</sub

https://cyberleninka.org/article/n/990976.pdf

Transient Modeling of NOX Reduction in Automobile Exhausts

We have explored the possibility of distributed temperature sensing using fiber Bragg gratings for the study of coal gasification. A laboratory model has been constructed to carry out such studies and the corresponding distributed temperature sensing results are reported.

Preeti Aghalayam

Papers

Kinetics of dimerization of isobutylene in the presence of ion exchange resin

CFD - A virtual platform for teaching concepts in non-ideal Chemical Reactors

Optimizing the synthesis of Ag/ <scp> γ‐Al <sub>2</sub> O <sub>3</sub> </scp> for selective reduction of <scp>NOx</scp> with <scp> C <sub>3</sub

Transient Modeling of NOX Reduction in Automobile Exhausts

Investigation of Coal Gasification Through Distributed Temperature Sensing Using Fiber Bragg Gratings