http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Srihiranpullop, Sunee,Praserthdam, Piyasan 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.6
The main goal of this contribution was to study the probability of chain growth of coke on metal sites and on support sites for hexane dehydrogenation. The coke structure of the catalysts examined by IR was found to have the aromatic structure. Soxhlet extraction coupled with GC-14B(DB1 column) analysis was mainly employed for coke composition analysis and determination of the probability of chain growth (alpha value). It was found that the soluble coke was mainly composed of C_(8)-C_(12) on both sites. Interestingly, the probabilities of chain growth on both sites were identical. However, the extracted coke on the metal site was more easily removable and had lower carbon numbers than that on the support site. Moreover, the addition of promoter, especially of K promoter, was sensitive to inhibit the probability of chain growth, resulting in the reduction of the amount of coke.
Mongkhonsi, Tharathon,Praserthdam, Piyasan,Srihiranpullop, Sunee 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.5
The effect of K addition on the amount and dispersion of carbon deposition on metal sites and support sites was investigated on a physical mixture for hexane dehydrogenation. TPO, BET and ESR experiments were used for characterization. The K addition significantly decreases catalyst deactivation involving the amount of coke deposits and the density of carbon radicals on the metal and support sites because of ensemble and electronic effects, especially on the metal sites. Coke on the metal sites associated with carbonaceous species rich in hydrogen is less polymerized than coke on the support sites, corresponding to a more graphitic-like carbon.