Low-Pressure Hydrodesulfurization Catalysts of Heavy Gas Oil Using Activated Bentonite and Kaolin Clay Supports

This study introduces a cost-effective and sustainable strategy for hydrodesulfurization (HDS) by employing activated kaolin and bentonite as dual-layer catalyst supports for the removal of sulfur from heavy gas oil (10,200 ppm of sulfur). The work focuses on the kinetic behavior of nine sulfur species. In contrast to earlier studies using single-clay supports, this novel dual-clay configuration improves the catalytic efficiency under mild HDS conditions. The catalyst, containing 5% Co and 10% Mo, was evaluated under industrially relevant conditions (225-370 °C, 12 bar, and a low H₂/HC ratio of 1:50), minimizing energy and hydrogen requirements. The optimal setup of a dual-bed reactor with Co-Mo/kaolin on top and Co-Mo/bentonite beneath achieved 93.38% sulfur removal. This method not only complies with environmental regulations by producing cleaner fuels but also reduces the cost through the use of locally sourced clays rather than expensive synthetic supports. Kinetic analysis revealed a first-order behavior, with Co-Mo metals notably lowering the activation energy.