Showing papers by "Guangji Hu published in 2014"

Ultrasonic oil recovery and salt removal from refinery tank bottom sludge.

Abstract: The oil recovery and salt removal effects of ultrasonic irradiation on oil refinery tank bottom sludge were investigated, together with those of direct heating. Ultrasonic power, treatment duration, sludge-to-water ratio, and initial sludge-water slurry temperature were examined for their impacts on sludge treatment. It was found that the increased initial slurry temperature could enhance the ultrasonic irradiation performance, especially at lower ultrasonic power level (i.e., 21 W), but the application of higher-power ultrasound could rapidly increase the bulk temperature of slurry. Ultrasonic irradiation had a better oil recovery and salt removal performance than direct heating treatment. More than 60% of PHCs in the sludge was recovered at an ultrasonic power of 75 W, a treatment duration of 6 min, an initial slurry temperature of 25°C, and a sludge-to-water ratio of 1:4, while salt content in the recovered oil was reduced to <5 mg L(-1), thereby satisfying the salt requirement in refinery feedstock oil. In general, ultrasonic irradiation could be an effective method in terms of oil recovery and salt removal from refinery oily sludge, but the separated wastewater still contains relatively high concentrations of PHCs and salt which requires proper treatment.

Investigation of Impact Factors on the Treatment of Oily Sludge using a Hybrid Ultrasonic and Fenton's Reaction Process

Abstract: In this study, a hybrid ultrasonic and Fenton's reaction process (US/Fenton) was applied for oily sludge treatment. The impacts of four different factors on the reduction of total petroleum hydrocarbons (TPH) in oily sludge were investigated. These include the initial sludge content, the molar ratio of hydrogen peroxide to iron (H2O2/Fe2+), the ultrasonic power, and the ultrasonic treatment duration. Taguchi experimental design method was used to arrange laboratory experiments. The results indicated that a TPH reduction rate of up to 88.1% was reached with an initial sludge content of 20 g/L, a H2O2/Fe 2+ molar ratio of 4:1, an ultrasonic treatment time of 5 min, and an ultrasonic power of 60 W. The initial oily sludge content and ultrasonic treatment duration were found to be the most significant factors affecting the US/Fenton treatment of oily sludge.