Ni/γ-Al2O3催化剂上萘加氢生成十氢萘的催化反应研究

采用Ni/Al₂O₃催化剂，在高压固定床反应器中考察了反应温度、压力、空速和氢油体积比比等因素对萘饱和加氢反应行为的影响，尤其是反应条件对反式十氢萘和顺式十氢萘选择性的影响。研究表明，反式十氢萘和顺式十氢萘的选择性与反应操作条件密切相关；反式十氢萘与顺式十氢萘的比例随着氢油比和温度的升高而增加，而随着压力和空速的增加而减小。在反应温度260-290℃、反应压力为5-7 MPa、空速为1-1.5 h^-1及氢油体积比大于250时，十氢萘的选择性最高可达99%以上，萘的转化率接近100%，产物中反式和顺式十氢萘的比例最高，可达4.0左右。对Ni/γ-Al₂O₃催化剂稳定性进行了考察，初步发现催化活性组分的烧结或流失是催化剂失活和影响产物中反式十氢萘和顺式十氢萘比例的主要原因。

Effect of reaction conditions on the hydrogenation of naphthalene to decalin over Ni/Al2O3 catalyst

The effect of reaction conditions, including temperature, pressure, space velocity and hydrogen to oil ratio, on the hydrogenation of naphthalene to decalin over Ni/Al₂O₃ catalyst was investigated in a high pressure fixed bed reactor. The results indicate that the conversion of naphthalene and the selectivity to tran-decalin and cis-decalin are closely related to the reaction conditions. The ratio of tran-decalin to cis-decalin increases with an increase in the hydrogen to oil ratio and reaction temperature, but decreases with an increase in the liquid hourly space velocity (LHSV) and reaction pressure. Under a temperature 260-290℃, 5-7 MPa, a LHSV 1-1.5 h^-1, and a hydrogen to oil ratio higher than 250, the conversion of naphthalene is 100% and the selectivity to decalin is close to 100%, with a tran-decalin to cis-decalin ratio of about 4.0. Meanwhile, it was found that the sintering and/or loss of active component are the main factors that cause the deactivation of Ni/Al₂O₃ catalyst in naphthalene hydrogenation and influence the ratio of tran-decalin to cis-decalin in the products.