Selective hydrocracking of tetralin for light aromatic hydrocarbons

Hydrocracking (HYC) of tetralin was studied in a fixed-bed down-flow reactor under 4 MPa as a model reaction for polyaromatic hydrocarbons (PAHs) conversion to light aromatic hydrocarbons such as BTX and C-9 aromatics. HYC catalysts were prepared by supporting various metals, (Ni, Ni-Sn and CoMo-S) possessing different hydrogenation (HYD) activity, on H-Beta. HYC of tetralin over Ni/H-Beta catalysts with various Ni contents (1-10 wt%) resulted in a non-selective HYC behavior to give low BTX yield but high yields of gaseous and naphtha products due to strong HYD activity of Ni. The HYD activity of Ni was suppressed by forming Ni-Sn intermetallic compounds by Sn addition. Thus, Ni-Sn/H-Beta catalysts showed BTX and BTX+C(9)A (C-9 aromatics) yields as high as 48.1 wt% and 53.1 wt%, respectively. The BTX and BTX+C(9)A yields corresponded to about 75 and 83% of the theoretical yield, respectively. CoMo-S/H-Beta, whose metal showed the lowest HYD activity, also exhibited BTX (47.4 wt%) and BTX+C(9)A (55.5 wt%) yields comparable to those obtained over Ni-Sn/H-Beta. Besides metallic function in HYC catalysts, H-2/tetralin molar ratio greater than 4 and H-Beta with a moderate acidity are desirable to achieve a highly selective HYC of tetralin into BTX with high yield at low hydrogen consumption. (C) 2015 Elsevier B.V. All rights reserved.