No abstract

The oily sludge from crude oil contains hazardous BTEX (benzene, toluene, ethylbenzene, xylene) found in the bottom sediment of the crude oil tank in the petroleum refining plant. This study uses microwave treatment of the oily sludge to remove BTEX by utilizing the heat energy generated by the microwave. The results show that when the oily sludge sample was treated for 60 s under microwave power from 200 to 300 W, the electric field energy absorbed by the sample increased from 0.17 to 0.31 V/m and the temperature at the center of the sludge sample increased from 66.5 °C to 96.5 °C. In addition, when the oily sludge was treated for 900 s under microwave power 300 W, the removal rates were 98.5% for benzene, 62.8% for toluene, 51.6% for ethylbenzene, and 29.9% for xylene. Meanwhile, the highest recovery rates of light volatile hydrocarbons in sludge reached 71.9% for C3, 71.3% for C4, 71.0% for C5, and 78.2% for C6.

No abstract

The sludge in this study was obtained from refinery crude oil storage tanks. It contained a high proportion of hydrocarbon composition and harmful substances (such as polycyclic aromatic hydrocarbons and benzene). Through the microwave irradiation treatment process, the harmful substances were removed from the sludge which was then recycled and combined with agricultural waste mushroom substrates to produce refuse derived fuel (RDF). The results showed that the calorific value of RDF was 7279 cal/g when the blending ratio (wt/wt) of oil sludge and mushroom substrates was 5:5. On the other hand, when the portion of the mushroom substrates was increased, the sludge became easier to ignite with better combustion reaction. When the blending ratio (wt/wt) was changed from 8:2 to 5:5, the ignition index and comprehensive performance index were increased by 51.9 and 50.2%. Therefore, mixing the sludge with agricultural waste mushroom substrates is in line with the concept of waste recycling and circular economy.

The rate of gas diffusion is inversely proportional to the gas molecule diameter; hydrogen gas molecular has smaller diameter and thus it has a greater diffusion coefficient than methane. Results of laboratory studies shown that when a gas mixture consisting of H2/CH4 = 30:70 is treated in a Hollow-fiber member under 5 kg/cm2, the hydrogen concentration is raised from 30 mol% to 71 mol%. If the Hollow-fiber member is re-arranged in series connection without controlling the operating pressure (free permeation), the recovered hydrogen concentration can be as high as 88 mol%. Additionally, using H2/CH4 = 50:50 as the influent gas mixture and controlling the influent pressure at 5 kg/cm2, the resulting hydrogen concentration can be raised from 50 mol% to 92 mol%, if the Hollow-fiber member is re-arranged in series connection without controlling the permeating pressure (free permeation), the recovered hydrogen concentration can reach 94 mol%. Therefore, Hollow-fiber member can be implemented to recover hydrogen gas from the hydrogen-rich petrochemical process tail gas at low pressure; the recovered hydrogen can be further utilized with higher add-on value. This hydrogen-recovery method has the advantage of low capital cost, simple to operate and small energy consumption.