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

Abstract

The sulfur of coal limits its clean utilization, while the biodesulfurization technology shows great development potential and application prospects for coal desulfurization. With a view to studying the different sulfur metabolism preferences of bacteria, two‐step bioleaching desulfurization of coal was proposed in this paper in which the organic sulfur desulfurizing bacteria and inorganic sulfur oxidizing bacteria were, respectively, used to remove sulfur from coal. An organic sulfur desulfurizing strain, Rhodococcus erythropolis SX‐12, was isolated from petroleum‐polluted soil collected from the Daqing Oilfield, which has been discovered to be capable of degrading dibenzothiophene (DBT) with an optimum temperature of 30°C and an initial pH of 7.0. Rhodococcus erythropolis SX‐12, as organic sulfur desulfurizing bacteria, were employed for the first step bioleaching desulfurization. Laboratory‐preserved Acidithiobacillus ferrooxidans GF, an inorganic sulfur oxidizing strain, was applied to second step bioleaching desulfurization. After conducting two‐step bioleaching, the sulfur content of the raw coal decreased from 4.973% to 1.729% and the total desulfurization rate of 65.23% was obtained after 30‐day incubation. Therefore, the “two‐step” leaching biodesulfurization test is more likely to provide a new strategy for the process design of biodesulfurization of coal.

Science and Technology Progress on the Desulfurization Process of Crude Oil

“…The cost operation of the intracellular enzymes is also cheaper because the cost for enzyme isolation and purification is not required. Several intracellular enzymes in the living microorganisms have been reported for the biodesulfurization process such as Rhodococcus spp , Arthrobacter , Agrobacterium , Pseudomonas , Gordonia , Brevibacterium , and Mycobacterium 143–157 . These microorganisms utilize organosulfur compound in crude oil as their food and energy source.…”

“…Different strain of microorganism gave different % sulfur removal on the biodesulfurization process. Rhodococcus erythropolis strain ATCC53968, HN2, and SX‐12 yielded 90%, 80%, and 65% sulfur removal, respectively 151–153 . Therefore, recent research is focused on the genetic modification of the sulfur bacteria having higher sulfur tolerance, faster desulfurization process, and higher % sulfur removal.…”

An effective method to remove organic sulfur in coal: Effects on the physicochemical properties and combustion kinetics

“…In order to study the biodesulfurization law, four basic factors, including the coal particle size (in the range of À0.075, 0.075-0.125, 0.125-0.5, 0.5-0.63 mm), inoculum amount (in the range of 10, 15, 20, 25 ml), coal slurry concentration (in the range of 0.3, 0.4, 0.5 0.6 g/50 ml) and the pH values of culture medium (in the range of 5,6,7,8) were considered to explore effects on the reduction of total sulfur in the orthogonal array(L 16 ) with four levels and four factors.…”

“…Inorganic sulfur, mostly in the forms of pyrite and sulfates, can be removed by physical desulfurization approach, such as froth flotation and gravity separation. Sulfates are barite, gypsum, and anhydrite, 4,5 while organic sulfur exists in the form of thiophene heterocyclic compounds, mercaptan, thioether, and so forth. It is mainly embedded in the macromolecular structure of coals, which is more difficult to be removed by using the conventional physical desulfurization method 6 .…”

MOFs for desulfurization of fuel oil: Recent advances and future insights

“…For instance, BDS requires suitable thiophilic bacteria and harsh temperature and pressure to obtain ultra‐deep fuel. [ 17 ]…”