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Energy & Fuels 2003, 17, 850-856
Optimization of Catalyst for Methanol Synthesis by a Combinatorial Approach Using a Parallel Activity Test and Genetic Algorithm Assisted by a Neural Network Tetsuo Umegaki, Yuhsuke Watanabe, Noritoshi Nukui, Kohji Omata, and Muneyoshi Yamada* Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aoba07, Aramaki, Aoba-ku, Sendai 980-8579 Received October 15, 2002
Optimization of a Cu-Zn-Al-Sc oxide catalyst for methanol synthesis from syngas was performed by a combinatorial approach using a genetic algorithm (GA) with/without various neural networks (NNs). Performance of optimum catalysts found by the various methods was compared. The catalyst with maximum activity was found by the combination of GA and radial basis function network (RBFN) in the optimization of Cu-Zn-Al-Sc oxide catalyst composition. Therefore this method was found to be the most efficacious method. In addition, we conducted the optimization on the RBFN with a larger population in the GA program to find the best catalyst in the early stage of evolution. On the other hand, we also tried to optimize simultaneously both composition and calcination temperature of a Cu-Zn oxide catalyst. In that case, the optimum catalyst was found by the combination of GA and back-propagation network. Thus, GA is a more robust tool when it is combined with NNs.
Introduction As one of chemicals mainly used for propellant, dimethyl ether (DME) is synthesized in a two-stage process in industry. In the first stage, Cu-based oxide catalyst is used for methanol synthesis from syngas involving CO, CO2, H2; in the second stage, a solid acid catalyst such as γ-alumina is used for the dehydration of methanol. Since DME is reevaluated as the good candidate for high-quality diesel fuel because of its low emission, an economic and large-scale process based on a huge natural gas reservoir is required to produce DME as fuel. On the other hand, we are going to suggest a compact process to produce DME from dispersed unused carbon resources, for example, the dispersed unused small-size natural gas reservoirs (those pressures are
