Abstract
Oily sludge (OS) contains a large number of hazardous materials, and froth flotation can achieve oil recovery and non-hazardous disposal of OS simultaneously. The influence of flotation parameters on OS treatment and the flotation mechanism were studied. OS samples were taken from Shengli Oilfield in May 2017 (OSS) and May 2020 (OST), respectively. Results showed that Na2SiO3 was the suitable flotation reagent treating OSS and OST, which could reduce the viscosity between oil and solids. Increasing flotation time, impeller speed and the ratio of liquid to OS could enhance the pulp shear effect, facilitate the formation of bubble and reduce pulp viscosity, respectively. Under the optimized parameters, the oil content of OST residue could be reduced to 1.2%, and that of OSS could be reduced to 0.6% because of OSS with low heavy oil components and wide solid particle size distribution. Orthogonal experimental results showed that the impeller speed was the most significant factor of all parameters for OSS and OST, and it could produce shear force to decrease the intensity of C-H bonds and destabilize the OS. The oil content of residue could be reduced effectively in the temperature range of 24–45 °C under the action of high impeller speed.
Highlights
Accepted: 26 November 2021Oily sludge (OS), which contains a large number of carcinogenic, teratogenic and mutagenic petroleum hydrocarbons, is one of the hazardous wastes inevitably produced in the process of exploration, storage, transportation and refining of crude oil [1,2]
The technologies of solvent extraction [6,7], ultrasonic treatment [8,9], pyrolysis [1,10], freeze-thaw method and hot washing technology with chemicals could achieve the goal of oil recovery from OS [11,12], while each technology had its limitations [3,7]
The freeze-thaw method could separate crude oil from solid surface in OS at low temperature of −20 ◦ C, which was suitable for cold regions and showed poor effect on OS treatment with complex physicochemical properties [11,13,14]
Summary
Accepted: 26 November 2021Oily sludge (OS), which contains a large number of carcinogenic, teratogenic and mutagenic petroleum hydrocarbons, is one of the hazardous wastes inevitably produced in the process of exploration, storage, transportation and refining of crude oil [1,2]. The combination of resource recovery and harmless disposal is the optimal technology for OS treatment, and the separation of oil from solid surface is the key step. The freeze-thaw method could separate crude oil from solid surface in OS at low temperature of −20 ◦ C, which was suitable for cold regions and showed poor effect on OS treatment with complex physicochemical properties [11,13,14]. The oil content of residue could be decreased to a very low level by employing pyrolysis or microwave method treating OS at high temperature of 300–600 ◦ C, Published: 1 December 2021
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
