煤焦油中芳烃(萘)的加氢饱和试验

Hydrogenation saturation of aromatic compounds (naphthalene) in coal tar

为了优化煤焦油加氢制取燃料油过程中芳烃的加氢饱和反应工艺,选取萘作为煤焦油中芳烃的模型化合物,在固定床加氢反应器上,使用MoNiWP/γ-Al2O3催化剂,探究反应温度、压力、体积空速及氢油体积比对萘的转化率以及四氢萘和十氢萘选择性的影响.研究煤焦油中不同质量分数的二苯并噻吩(S)、喹啉(N)和邻甲酚(O)杂原子的存在对芳烃化合物加氢饱和的影响,并初步考察多种芳烃化合物加氢饱和的效果.结果表明:MoNiWP/γ-Al2O3催化剂在萘的加氢饱和反应中表现出良好的催化活性;反应温度和体积空速对萘加氢反应的影响比较明显,且萘加氢饱和的最佳反应条件为温度320℃,压力4MPa,氢油体积比600∶1以及体积空速2h-1;微量质量分数的S和N对萘的加氢饱和影响不大,但是当S、N质量分数高于0.15%,O质量分数高于0.30%时,萘加氢反应,尤其是第二个苯环的加氢饱和反应都受到明显的抑制;不同种类的芳烃类化合物的加氢饱和反应存在相互影响的现象.因此,建议在煤焦油加氢精制工艺中使用两步加氢,并对原料进行脱酚处理.

Naphthalene was chosen as the model compound of aromatics in coal tar to improve the aromatics hydrogenation process in coal tar hydrogenation.The influence of temperature,pressure,volume space velocity and hydrogen to oil volume ratio on conversion of naphthalene,accompany with the selectivity of tetralin and decalin,was investigated over MoNiWP/γ-Al2O3 catalyst in a fixed bed reactor.The effect of heteroatoms was studied by adding different mass fractions of S（dibenzothiophene）,N（quinoline）and O（o-cresol）,respectively.And the hydrogenation of multiple aromatic compounds was primarily investigated.The results reveal that：MoNiWP/γ-Al2O3 catalyst shows great activity on the hydrogenation of naphthalene.Reaction temperature and volume space velocity have more obvious effect on reaction.The optimized process conditions of hydrodearo-matization was at 320℃,4MPa,hydrogen to oil volume ratio of 600∶1and volume space velocity of 2h^-1.Trace mass fraction of S and N hardly worked on naphthalene hydrogenation.When the mass fraction of S,N was over 0.15% and that of O was higher than0.30%,the hydrogenation reaction,especially saturation of the second benzene ring of naphthalene,wasinhabited.Hydrogenation saturation reactions of different kinds of aromatic compounds influence mutually.Therefore,two step hydrogenation of coal tar is recommended and removing the phenols in coal tar in advance is also important.