Organic sulfur removal from coal by electrolysis in alkaline media

Desulfurization kinetics and mineral phase evolution of bauxite water slurry (BWS) electrolysis

“…All the methods are still problematic due to lower efficiency, surrounding pollution and harsh reaction conditions, hindering their application. However, ore water slurry electrolysis can solve above problems in removal of sulfur (Zhong et al, 2011;Wapner et al, 1988;Farooque and Coughlin, 1979;Lam et al, 2012;Shen et al, 2012). Electrolysis not only achieved higher desulfurization efficiency under mild condition, but also reduced the pollution of the environment risk (Li, 2000;Lalvani and Pata, 1983;Lavani, 1985;Lalvani et al, 1985).…”

A review of electrochemical desulfurization technologies for fossil fuels

“…Choosing a suitable potential for electrolysis is a crucial step in potentiostatic methods, since the electrochemical desulfurization of fossil fuels shows potential dependence. Wapner et al [28] observed this potential dependence in the desulfurization of coal. They found that higher potentials (1.6-2.0 V vs. SCE) facilitated the organic sulfur removal, and lower potentials (1.2-1.4 V vs. SCE) preferred for pyritic sulfur removal.…”

“…Interestingly, it has been observed that desulfurization of organic sulfur compounds in NaOH occurred even without an applied potential [40]. Wapner and Lalvani [28] observed that up to 56% sulfur removal from coal slurries in 1 M NaOH after 6 h under open circuit conditions, during which up to 42% of the organic sulfur content was removed. One disadvantage of this method is the formation of ash.…”

“…High desulfurization conversion has been achieved under alkaline conditions using desulfurization mechanism that involved hydroxyl radicals [27,28].W a n ge ta l . [39] and Comninellis et al [34] proposed that free hydroxyl radicals could oxidize organic sulfur to sulfone or sulfoxide.…”

Coal desulfurization by bacterial treatment and column flotation. Final report

“…Unfortunately, at room temperature the alkali is not able to cleave the more strongly-bonded sulfur compounds without an added energy input. Electrolysis appears to be capable of supplying the energy for the alkali reaction (Lalvani and Hines, 1987;Wapner et al, 1988). At approximately ambient temperature, the reaction removes the pyritic sulfur and roughly 40% of the organic sulfur.…”