Developing an Approach for Calculating Theoretical Minimum Hydrogen Consumption during Catalytic Hydrotreating of Diesel.

Identifying the unnecessary H consumption existing in diesel hydrotreating process and calculating theoretical minimum H consumption are extremely critical for reducing H consumption in consideration of carbon reduction and resource utilization improvement. In this work, chemical reactions happened during diesel hydrotreating were categorized into hydrodesulfurization (HDS), hydrodenitrogenation (HDN), saturation of monocyclic aromatic hydrocarbons (MAHs), saturation of polycyclic aromatic hydrocarbons (PAHs), hydrogenation of olefins (HGO) and hydrocracking reactions (HCR). Then, in order to gain insights into where and how much H can be reduced, the ideal molecular compositions of the products were analyzed when theoretical minimum H was achieved for each type of reactions, which can give a genuine value of average relative molecular weight and average number of moles of H consumed per mole of reactants, leading to the establishment of method for calculating theoretical minimum H consumption. Additionally, the above method was used to calculate theoretical minimum H consumption of five diesel feedstocks with different properties to study the influence of content of S, N and PAHs in the feed on theoretical minimum H consumption. This method can provide guidance for experiments of H consumption reduction, and also help the refineries to save potential costs of H.