A Review on Bio- And Adsorptive Desulfurization of Diesel Fuel

Abstract

Aims: To review some previous work on biodesulfurization and adsorptive desulfurization of diesel fuel. Study Design: The emissions from fossil fuels have been established to be a major contributor to global warming and acid rain which deteriorates the environment and infrastructures. In refineries, hydrodesulfurization (HDS) method is currently used to remove thiols, sulfides and thiophenes compounds present in lower-boiling petroleum fractions, but the removal of benzothiophenes (BT) and dibenzothiophenes (DBT) contained significantly in middle-distillate petroleum fractions (MDPF) e.g, diesel via HDS is difficult due to the presence of substitutions which are believed to sterically hinder access of the sulfur atom to the catalyst surface. Over the years there have been several regulatory standards and researches on limiting the sulfur content of petroleum products. The development of complimentary desulfurization techniques that will remove these recalcitrant compounds from the MDPF is therefore essential. Biodesulfurization (BDS), a process in which sulfur is removed from a substance by an enzymatic process yielding sulfate or sulfide as a product; and Adsorptive Desulphurization (ADS), a process which removes sulfur from a substance through the use of adsorbents are amongst the complementary methods being explored for the removal of sulfur present as DBT in MDPF. Methodology: The review highlights the study by some listed authors on biodesulfurization and adsorptive desulfurization of diesel fuel respectively. Results: The potentiality of ADS using different types of adsorbents are continuous area of research as little or no report of their commercialization has been reported. Also, for the BDS, most research focus has been on aerobic desulfurization with currently little evidence for the potentiality of a commercially significant anaerobic desulfurization. Conclusion: The current trends toward stricter regulations on the content of sulfur in fuels provide enough incentive for the continued search for improved complementary desulfurization technique.