New technology recommendation: Pyrolysis of oily sludge combined with high-temperature thermal oxidation treatment!

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Recommended technologies ▶ I. Technology name: Co-treatment technology involving pyrolysis and high-temperature thermal oxidation of oil-containing sludge. Utilizing biomass as an additive, this technology achieves efficient solid-liquid separation of highly moist sludge and aged oil through interface regulation, particle size grading adjustment, and drying techniques； A low-temperature catalytic pyrolysis technique for oily sludge was developed using modified clay as a catalyst, enabling the recovery and reuse of crude oil resources ； To minimize the environmental impact, particleized fuel preparation and high-temperature thermal oxidation technologies were developed based on the pyrolysis of oily sludge, thereby enabling the harmless treatment of such sludge. II. Description of the advanced features (1) For the first time, biomass materials were utilized; through particle size grading, rapid and efficient dehydration of oil-containing sludge was achieved. The moisture content of the residue after treatment ranged from 58.6% to 60.5%, which is a reduction of over 10% compared to the moisture content of residue treated using conventional technologies ； Interface regulation technology was applied to the treatment of aged oil. At an oil-to-water ratio of 1:4, a treatment agent was added; after heating and stirring at 50–60°C for 1 hour, centrifugal dehydration was carried out for 15 minutes. The water content in the recovered oil was below 0.5%, meeting the standards for water content in crude oil intended for transportation. (2) The oil-containing sludge drying technology enables the drying of such sludge at lower temperatures; after drying, the volume reduction rate is over 90%, and the oil content in the remaining residue is 5% to 8%. (3) The pyrolysis catalyst for oil-containing sludge and the low-temperature catalytic pyrolysis treatment technology: compared to conventional pyrolysis treatment technologies, when the amount of catalyst added is 1%, the oil recovery rate exceeds 86% ； The pyrolysis temperature was reduced from above 480–500°C to 410–420°C, and the treatment time was shortened from above 4 hours to 2–2.5 hours. (4) Sulfur-fixing agents, combustion promoters, and catalysts are used in the clean combustion process of pyrolysis residues, enabling the calorific value of the resulting oil-containing sludge-based granular fuel to exceed 5000 kJ/kg, while reducing sulfur dioxide emissions in the exhaust gases by 90%. (5) High-temperature thermal oxidation treatment technology and equipment for oily sludge based on high-temperature oxygen-enriched oxidation reactions; the oil content in the residue after treatment is below 0.3%, dioxin levels in the exhaust gases are within acceptable limits, and the concentration of heavy metal ions in the residue leachate is far below the **standard. III. Case Studies Case 1: Tarim Oil Field The materials used originate from the residues resulting from the resource recovery treatment of oily sludge; their oil content is 4%–5%. The oily sludge is transported to a thermal oxidation unit via automatic screw conveyors for thermal oxidation treatment. In 2016, industrial facilities with a processing capacity of 300 t/d were built at the Lünnan, Tazhong, and Shaya sites respectively to carry out activities related to the treatment of oil field sludge. From 2017 to 2019, the cost of sludge treatment was 576 yuan per ton; a total of 249,000 cubic meters of sludge were treated during those three years, generating economic benefits of 143.424 million yuan (with a profit of 32.5633 million yuan). In 2020, the treatment cost was 460 yuan per ton, and 121,400 cubic meters of sludge were treated, resulting in economic benefits of 55.844 million yuan (with a profit of 7.0196 million yuan). This technology is used to treat the residues resulting from the resource utilization of oily sludge. The oil content values before and after treatment are as follows: Analysis item, Before treatment, After treatment; Oil content %: 4–50.02%. Case 2: The oily sludge treatment project at the Third Oil Production Plant of Changqing Oilfield Branch. The materials used come from the transfer stations and combined stations in the oil production areas, as well as from oil tanks, sedimentation tanks, wastewater tanks, and the sludge in oil separation ponds. Additionally, it includes operational sludge generated from drilling, operations, and pipeline leaks in those oil areas, as well as oily sludge from refineries located near such sites. The above sludges can be divided into two categories based on their liquid content: ① Sludges generated at oil fields, and high-water-content sludges resulting from wastewater treatment; these have a water content of 95% and an oil content of around 2%. ②The sludge from oil field tank cleaning has a high moisture content of 85%, with an oil content of around 10%. This technology was used to treat oilfield sludge and sludge resulting from oilfield flushing; the data on moisture content and oil content before and after treatment are as follows: Treatment subject and analysis parameter – Before treatment / After treatment: Moisture content of oilfield sludge, %: 95