正己烷存在下的氢选择性催化燃烧

Selective hydrogen combustion over Pt-Sn/Al_2O_3 catalyst in the presence of n-hexane

以正己烷作为裂解原料烃类代表,Pt-Sn/Al2O3催化剂作为氢选择性燃烧催化剂,对直接内加热方式提供热量促使裂解原料达到可裂解温度的可行性进行了研究。结果表明,温度相同时,Pt-Sn/Al2O3催化剂存在时氢燃烧的选择性明显高于无催化剂存在时的非催化氢燃烧过程,Pt-Sn/Al2O3催化剂是优良的氢选择性燃烧催化剂。该催化剂在催化氢选择性燃烧过程中,存在一个临界温度点650℃。当物流入口温度低于650℃时,氢燃烧选择性达90%以上;高于650℃时,由于非催化氢燃烧所占总燃烧反应比例加大,造成氢燃烧选择性有所降低。同时,在一定温度下,要获得高的氢燃烧选择性及氧气转化率,须综合考虑氢烃比和氢氧比的影响。

The selective hydrogen combustion（SHC） in the presence of n-hexane was studied over Pt-Sn/Al2O3 catalyst to investigate the feasibility of directly heat supply for pyrolysis process.With air as the oxygen source and n-hexane as the representative of cracking hydrocarbons feedstock,the selective hydrogen catalytic combustion was compared with hydrogen non-catalytic combustion under various temperatures.The results indict that Pt-Sn/Al2O3 is a good catalyst for SHC;the selectivity of Pt-Sn/Al2O3 catalyzed hydrogen combustion is remarkably higher than that of non-catalytic hydrogen combustion.There exists a critical temperature for Pt-Sn/Al2O3 catalyzed SHC reactions.The selectivity of catalytic SHC keeps at 90% when the feedstock inlet temperature is below 650℃;however,it decreases at elevated inlet temperature.Moreover,the ratio of hydrogen to hydrocarbon and the ratio of hydrogen to oxygen may also significantly influence the selectivity of SHC under certain temperature.