Computational optimization of catalyst distributions at the nano-scale
Artikel i vetenskaplig tidskrift, 2017

Catalysis is a key phenomenon in a great number of energy processes, including feedstock conversion, tar cracking, emission abatement and optimizations of energy use. Within heterogeneous, catalytic nano-scale systems, the chemical reactions typically proceed at very high rates at a gas-solid interface. However, the statistical uncertainties characteristic of molecular processes pose efficiency problems for computational optimizations of such nano-scale systems. The present work investigates the performance of a Direct Simulation Monte Carlo (DSMC) code with a stochastic optimization heuristic for evaluations of an optimal catalyst distribution. The DSMC code treats molecular motion with homogeneous and heterogeneous chemical reactions in wall-bounded systems and algorithms have been devised that allow optimization of the distribution of a catalytically active material within a three-dimensional duct (e.g. a pore). The objective function is the outlet concentration of computational molecules that have interacted with the catalytically active surface, and the optimization method used is simulated annealing. The application of a stochastic optimization heuristic is shown to be more efficient within the present DSMC framework than using a macroscopic overlay method. Furthermore, it is shown that the performance of the developed method is superior to that of a gradient search method for the current class of problems. Finally, the advantages and disadvantages of different types of objective functions are discussed.

Catalysis

Stochastic optimization

DSMC

Optimization

Nanoscale

Författare

Henrik Ström

Chalmers, Tillämpad mekanik, Strömningslära

Chalmers, Energi och miljö, Energiteknik

Applied Energy

0306-2619 (ISSN)

Vol. 185 Part 2, Special Issue 2224-2231

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Ämneskategorier

Materialteknik

Energiteknik

Kemiska processer

Kemiteknik

Nanoteknik

Strömningsmekanik och akustik

Fundament

Grundläggande vetenskaper

DOI

10.1016/j.apenergy.2015.10.171

Mer information

Skapat

2017-10-08