Experimental Research on Coal Biodesulfurization by Mixed Culture Column Leaching

Abstract

<jats:p>The removal of sulfur in coal before its combustion can reduce its environmental pollution, and microbial desulfurization should have good application prospects. Some species of bacteria have been used in the process of coal desulfurization, and our previous study demonstrated that mixed culture should be more efficient than pure culture by shaking cultivation. In this study, column leaching was investigated, due to its similarity to the industrial heap leaching. The mixed culture consisted of three strains of bacteria, which were Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans respectively. The ratio of the three strains of bacteria was 1: 1: 1. The column (50 cm height, 650 mm Inner Diameter) bioleaching experiments were carried out at ambient temperature. After desulfurization for 18 days, the ultimate desulfurization rate was 28.66% for total sulfur, which was higher than the previous study of J.Cara (with total sulfur desulfurization rate for 24% after 125 days). This study showed that ferric ions should be in proper concentration, and Leptospirillum ferrooxidans might be in lower ratio for reducing the precipitation of jarosite and improving the efficient of coal desulfurization.</jats:p>

Biodesulfurization of coal using Rhodococcus erythropolis SX‐12 and Acidithiobacillus ferrooxidans GF: A two‐step approach

“…And the total sulfur removal rate of 65.23% was obtained, in which the removal rate of organic sulfur was 81.45%, inorganic sulfur of 38.78%. Although pyritic desulfurization was worse than some of the reported results, 13 total desulfurization of the two-step approach was better than the majority of other leaching test results, 10,24,30 which demonstrated that two-step biodesulfurization could further expand in future. Compared with the total desulfurization rate of 67.83% of our previous flotation-biodesulfurization method, the "two-step" bioleaching method was slightly lower than it, 18 but it was a more energy-saving and economical technology.…”

“…After the test was finished, the coal samples were washed and dried, and the total sulfur content was measured by the Eschka method to calculate the desulfurization rate. The two forms of sulfur content in experimental coal, inorganic sulfur and organic sulfur, were determined according to the GB/T214‐2007 …”

“…The two forms of sulfur content in experimental coal, inorganic sulfur and organic sulfur, were determined according to the GB/T214-2007. 24…”

Research on the Effect of Surfactants on the Biodesulfurization of Coal

“…The adsorption of bacteria caused the etching of coal particles, which resulted in less mineral acid solution, which made the pH value of the system in the experimental group rise. However, the bacteria adsorbed on the coal particle surface could constantly metabolize pyrite sulfur effectively, and a large number of H + were generated, which caused a sustained drop in the pH of the desulfurization system …”

Biodegradation of dibenzothiophene and its application in the production of clean coal

“…Of the total sulphur, 43% was pyritic sulphur [178]. Subsequent studies on column reactors were undertaken by Yang et al [179]. They employed a 50 cm-high column, having an inner diameter of 650 mm.…”