Desulfurization of sour crude oil using an invasive weed adsorbent: An efficient, eco-friendly, and ultra-low-cost option

Abstract

Desulfurization is a technology commonly used by refineries to mitigate the environmental burden caused by toxic gas emissions from hydrocarbon fuels. Expanding global population will increase liquid fuel demand by 20% between 2018 and 2050, with a total consumption of 240 quadrillion British thermal units (Btu) in 2050. Conventional catalytic Hydrodesulfurization (HDS) accounts for high cost and severe operating conditions (high temperature, pressure, catalyst poisoning and H2S safety). While studies have shown that adsorptive desulfurization (ADS) is highly effective in the removal of organic sulfur, limitations in the regeneration of adsorbent and selection of adsorbent with suitable structure to remove organic sulfur compounds exist. On the other hand, Prosopis juliflora, the world's most threatening invasive weed causes multifaceted environmental problems. The present study offers a novel solution that addresses both these issues contributing to climate change. Desulfurization of sour crude oil sample is performed using chemical-free, non-activated charcoal obtained from invasive weed species as adsorbent. XRD analysis showed amorphous structure and FTIR analysis confirmed the presence of CC bending functional group of the adsorbent. Adsorption-desorption isotherm showed presence of mesopores with pore diameter of 2.718 ​nm. Kinetic study findings reported 46% removal of total sulfur. GCMS findings showed efficient removal of some organic sulfur, including 100% removal of dibenzothiophene 4-methyl -. The equilibrium data is best represented by Freundlich isotherm. ICP-OES tests indicate the removal of toxic elements as well. The cost of the adsorbent is USD 0.12628 per kg, the lowest among all the adsorbents known thus far. The present study describes a novel, ultra-low cost, efficient, eco-friendly, desulfurization process that implements a chemical-free, non-activated adsorbent, achieves synergy, and offers multi-dimensional benefits to the environmental development. To our knowledge, this is the first study to characterize desulfurization of sour crude oil using an invasive weed.