Facilitating the natural semi-drying of oily sludge by changing the form of water

• Published in: PloS one Vol. 16; no. 1; p. e0245430
• Main Authors: Liu, Yucheng, Wang, Maoren, Chen, Mingyan, Zhu, Meng, Liao, Maoqi
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.01.2021; Public Library of Science (PLoS)
• Subjects: Biology and Life Sciences; Bound water; Cement; Chemical agents; Chemical engineering; Chemical properties; Chemistry; Crude oil; Drying; Drying oils; Editing; Engineering and Technology; Evaporation; Exothermic reactions; Exploitation; Free water; Hazardous wastes; Heat; High temperature; Moisture content; Oil; Oil exploration; Organic matter; Oxidation; Petroleum; Petroleum engineering; Petroleum industry; Petroleum refining; Physical Sciences; Reaction time; Reagents; Research and Analysis Methods; Resource utilization; Sludge; Sludge drying; Temperature; Waste disposal; Waste management; Water absorption; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0245430

Reducing the water content of oily sludge is essential for the disposal of it. Despite conditioning and solid-liquid separation, the water content of oily sludge generally exceeds 65%. A large amount of this water exists in the form of emulsified and bound water, reducing the efficiency of water removal during the natural semi-drying process of oily sludge. To shorten the time required for natural semi-drying, this study applied an orthogonal test to screen an oily sludge modified material (OSM). The effect and mechanism of OSM on the natural semi-drying of oily sludge were studied using a thermal gravimetric analyzer (TGA), scanning electron microscope (SEM), surface tension measurement, and microscopic observations. The results show that when the ambient temperature exceeded 10°C, the OSM increased in mass by 8-10%, and the time required for the natural semi-drying of oily sludge was shortened from 15 days to less than 5 days. OSM can rupture the emulsion, reduce the surface tension, convert the emulsion and bound water in the oily sludge into free water, and accelerate the rate of water migration, diffusion, and natural evaporation from the inside of the oily sludge to the surface and air. The research results show that changing the form of water can speed up the drying of oily sludge, creating positive economic benefits in the process of oily sludge reduction and recycling.