A modified genetic algorithm of multiple selection strategies, crossover strategies and adaptive operator is constructed, and it is used to estimate the kinetic parameters in autocatalytic oxidation of cyclohexane. Th...A modified genetic algorithm of multiple selection strategies, crossover strategies and adaptive operator is constructed, and it is used to estimate the kinetic parameters in autocatalytic oxidation of cyclohexane. The influences of selection strategy, crossover strategy and mutation strategy on algorithm performance are discussed. This algorithm with a specially designed adaptive operator avoids the problem of local optimum usually associated with using standard genetic algorithm and simplex method. The kinetic parameters obtained from the modified genetic algorithm are credible and the calculation results using these parameters agree well with experimental data. Furthermore, a new kinetic model of cyclohexane autocatalytic oxidation is established and the kinetic parameters are estimated by using the modified genetic algorithm.展开更多
Autothermal steam reforming （ATR） of bio-oil, which couples the endothermic steam reform- ing reaction with the exothermic partial oxidation, offers many advantages from a technical and economic point of view. Effec...Autothermal steam reforming （ATR） of bio-oil, which couples the endothermic steam reform- ing reaction with the exothermic partial oxidation, offers many advantages from a technical and economic point of view. Effective production of hydrogen through ATR of bio-oil was performed at lower temperature with NiCuZnAl catalyst. The highest hydrogen yield from bio-oil reached 64.3% with a nearly complete bio-oil conversion at 600℃, the ratio of steam to carbon fed （S/C） of 3 and the oxygen to carbon ratio （O/C） of 0.34. The reaction conditions in ATR including temperature, O/C, S/C and weight hourly space velocity can be used to control both hydrogen yield and products distribution. The comparison between the ATR and common steam reforming of bio-oil was studied. The mechanism of the ATR of bio-oil was also discussed.展开更多
29Si-NMR and 1H-NMR were used to follow up the basic hydrolysis of tetraethyl orthosilicate （TOES） and the results showed that species of monomer, dimer, trimer, cyclic and polymer silicates were formed. The monomer...29Si-NMR and 1H-NMR were used to follow up the basic hydrolysis of tetraethyl orthosilicate （TOES） and the results showed that species of monomer, dimer, trimer, cyclic and polymer silicates were formed. The monomer and dimer were favorable for the high activity of zeolite. XRD, 13C CP/MAS and 29Si NMR were used to trace the crystallization process of hollow titanium silicalite zeolites （HTS）. The results showed that the induction period of HTS was 80 min, and subsequently it took next 10 min to form HTS and the remaining time of the crystallization period might function for cleaning up the pores and/or washing off the impurities from the HTS zeolite. The catalytic oxidation performance of HTS zeolite is different from that of the acid activity of zeolite in which the conventional definition of crystallinity does not reflect the catalytic oxidation activity proportionally. The synthesized HTS samples were character- ized by XRD, FT-IR, UV-Vis and Raman spectra. It was confirmed that Ti was incorporated into the zeolite framework. The synthesized HTS samples revealed good repeatability and high activity for oxidation of phenol into diphenol.展开更多
基金Supported by the National Natural Science Foundation of China (No. 20176046).
文摘A modified genetic algorithm of multiple selection strategies, crossover strategies and adaptive operator is constructed, and it is used to estimate the kinetic parameters in autocatalytic oxidation of cyclohexane. The influences of selection strategy, crossover strategy and mutation strategy on algorithm performance are discussed. This algorithm with a specially designed adaptive operator avoids the problem of local optimum usually associated with using standard genetic algorithm and simplex method. The kinetic parameters obtained from the modified genetic algorithm are credible and the calculation results using these parameters agree well with experimental data. Furthermore, a new kinetic model of cyclohexane autocatalytic oxidation is established and the kinetic parameters are estimated by using the modified genetic algorithm.
文摘Autothermal steam reforming （ATR） of bio-oil, which couples the endothermic steam reform- ing reaction with the exothermic partial oxidation, offers many advantages from a technical and economic point of view. Effective production of hydrogen through ATR of bio-oil was performed at lower temperature with NiCuZnAl catalyst. The highest hydrogen yield from bio-oil reached 64.3% with a nearly complete bio-oil conversion at 600℃, the ratio of steam to carbon fed （S/C） of 3 and the oxygen to carbon ratio （O/C） of 0.34. The reaction conditions in ATR including temperature, O/C, S/C and weight hourly space velocity can be used to control both hydrogen yield and products distribution. The comparison between the ATR and common steam reforming of bio-oil was studied. The mechanism of the ATR of bio-oil was also discussed.
基金Project supported by the National Science Foundation of China(2006CB202508)
文摘29Si-NMR and 1H-NMR were used to follow up the basic hydrolysis of tetraethyl orthosilicate （TOES） and the results showed that species of monomer, dimer, trimer, cyclic and polymer silicates were formed. The monomer and dimer were favorable for the high activity of zeolite. XRD, 13C CP/MAS and 29Si NMR were used to trace the crystallization process of hollow titanium silicalite zeolites （HTS）. The results showed that the induction period of HTS was 80 min, and subsequently it took next 10 min to form HTS and the remaining time of the crystallization period might function for cleaning up the pores and/or washing off the impurities from the HTS zeolite. The catalytic oxidation performance of HTS zeolite is different from that of the acid activity of zeolite in which the conventional definition of crystallinity does not reflect the catalytic oxidation activity proportionally. The synthesized HTS samples were character- ized by XRD, FT-IR, UV-Vis and Raman spectra. It was confirmed that Ti was incorporated into the zeolite framework. The synthesized HTS samples revealed good repeatability and high activity for oxidation of phenol into diphenol.
