Biotechnology of desulfurization of diesel: prospects and challenges

Abstract

To meet stringent emission standards stipulated by regulatory agencies, the oil industry is required to make a huge investment to bring down the sulfur content in diesel to the desired level, using conventional hydrodesulfurization (HDS) technology, by which sulfur is catalytically converted to hydrogen sulfide in the presence of hydrogen. These reactions proceed rapidly only at high temperature and pressure and therefore the capital cost as well as the operating cost associated with HDS very high. Biological desulfurization has the potential of being developed as a viable technology downstream of classical HDS. Various attempts have been made to develop biotechnological processes based on microbiological desulfurization employing aerobic and anaerobic bacteria. However, there are several bottlenecks limiting commercialization of the process. This review discusses various aspects of microbial desulfurization and the progress made towards its commercialization.

Biocatalytic desulfurization (BDS) of petrodiesel fuels

“…The reactivity of organosulfur compounds varies widely depending on their structure and the local sulfur atom environment. The conditions depend upon the level of desulfurization required (Gupta et al, 2005).…”

“…The reactivity of organosulfur compounds varies widely depending on their structure and the local sulfur atom environment. The conditions depend upon the level of desulfurization required (Gupta et al, 2005).HDS of diesel feedstock for a low-sulfur product requires a larger reactor volume, longer processing times, and substantial hydrogen and energy inputs. Deep HDS technology results in various problems in the process, which limit its usefulness: (i) the application of extreme conditions to desulfurize refractory compounds results in the deposition of carbonaceous coke on the catalysts; (ii) exposure of crude oil fractions to severe conditions including temperatures above about 360 u C decreases the fuel value of treated product; (iii) deep HDS processes need large new capital investments and/or have higher operating costs; (iv) the H 2 S that is generated poisons the catalysts and shortens their useful life; (v) deep HDS is affected by components in the reaction mixture such as organic heterocompounds and polyaromatic hydrocarbons (Egorova, 2003;Folsom et al, 1999;Konishi et al, 2000;Monticello, 1996).…”

Recent Advances in the Science and Technology of Desulfurization of Diesel Fuel Using Ionic Liquids

“…Additionally, BDS can effectively remove some key sulfur-containing compounds that are among the most difficult for HDS to treat. BDS can be used instead of, or complementary with, HDS [40][41][42][43][44][45][46][47][48][49][50][51][52].…”

Production of biosurfactants through biodesulfurization of spent engine oil – an experimental study

“…The reduction of sulfur in the spent engine oil is necessary to obtain ultra low sulfur diesel through pyrolysis. Biodesulfurization of spent oil using suitable microorganisms may serve as a promising process to eliminate the organosulfur compounds, as already studied in case of hydrodesulfurized diesel obtained from petroleum crude (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). In case of diesel, dibenzothiophene (DBT) and its alkylated homologues are biodesulfurized by the action of microorganisms like Rhodococcus sp.…”

“…These biosurfactants are value-added products which can be used for different industrial purposes, mainly as drilling mud in advanced oil recovery from wells (25). Although a few research studies on the biodesulfurization of diesel have already been reported (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Only a few (26) have been reported on the biodesulfurization of spent engine oil are available in the literature.…”