Optimizing hydrodesulfurization of naphtha using NiMo/graphene catalyst

This paper reports results of optimizing naphtha hydrodesulfurization (HDS) using NiMo/graphene catalyst as an alternative to the conventional CoMo/Al2O3 catalyst that has been widely used in the industry. The objectives of this study are to formulate the NiMo/graphene catalyst and to evaluate its efficacy in sulphur removal during HDS. The catalyst exhibited a noticeable transformation from amorphous to crystalline structure, as confirmed by XRD analysis. The experiments were conducted in a fixed-bed reactor, and the effects of reaction temperature, space velocity, and hydrogen pressure on sulphur removal were studied. The findings demonstrate that increasing the reaction temperature from 520 K to 600 K resulted in a substantial decrease in sulphur level in the product by 32.5 % when operating at a space velocity of 6 h−1. Increasing the hydrogen pressure from 1 MPa to 1.85 MPa resulted in sulphur content reduction in the product by 97.12 % at constant temperature of 600 K. Conversely, space velocity was inversely proportional to the sulphur removal at fixed temperature and hydrogen pressure. A response surface methodology and desirability function were employed to identify the optimal operating conditions. During optimization, desulfurization efficiency of 97.7 % was achieved when hydrogen pressure of 1.8 MPa, reaction temperature of 600 K, and space velocity of 3 h−1 were applied during HDS. There was an increase of 12.6 % from the industrial catalyst for naphtha HDS.