عنوان مقاله [English]
In this study, the capability of local bacteria, isolated from oily sludge in Kermanshah refinery oil tanks, and cultivation environment conditions effects on fuel oil upgrading were investigated. In order to isolate and purify microorganisms, liquid and solid culture media were used and the amount of microbial population increased during different stages. The isolated bacteria include the Pseudomonas aeruginosa and Rhodococus erythropolis. In these experiments, the selected variables included pH, temperature, time parameters, fuel oil concentration and microorganism concentration were used at different levels based on the conditions. Density and total sulfur reduction were used as responses parameters. Also, the effect of chemical surfactant on the responses was studied.
Based on the achieved results, the best conditions for sulfur removal and converting heavy cut to lighter one,, were obtained at pH = 6.5, temperature of 40 ℃, fuel oil concentration 0f 4 % (V/V) microorganisms’ concentration of 2 % (V/V) and 3 days, together with the addition of chemical surfactant. The SARA analysis results shown that total sulfur and density in untreated fuel oil were 25400 ppm and 0.9428 kg/L, respectively and in optimal treated one were 9400 ppm and 0.9096 kg/L, that demonstrate the conversion rate of fuel oil to gas oil is equal to 29.3% and reduction of total sulfur by more than 60%.