Petroleum sludge is one of the valuable hazardous waste materials in the oil industry, which forms at various stages of crude oil extraction, refining, and storage processes. The sludge formed in reservoirs leads to a reduction in reservoir volume, decreased accuracy in determining the amount of oil or products present in the reservoirs, and accelerates reservoir corrosion. Therefore, periodic disposal is necessary. Currently, there is no comprehensive management for the collection and resolution of petroleum sludges in the country's oil companies, and the collected sludges are stored in ponds in nature, leading to the loss of a significant volume of valuable hydrocarbons and causing various environmental pollutions. Hence, finding a solution for proper petroleum sludge management is essential. This study focused on the petroleum sludge resulting from the storage reservoirs of petroleum products. Initially, chemical and physical analyses were conducted to identify the sample structures, followed by investigating operational sludge removal methods. The study utilized methods such as extraction with geen solvents, mixing with crude oil, using solvents enhanced with ionic liquids and ultrasonic waves, and recovering oil from oily sludge via water-enhanced CO2 extraction. The separated samples were eva‎luated using the SimDis distillation method to determine the boiling point in the organic phase. Additionally, ASTM, UOP, and IP standards were used for the general analysis of the extracted hydrocarbons. The study revealed that the studied sludge sample consisted of 32% water, 12.2% solids, and 8.58% oil. For the first time in this research, geen solvents were used for petroleum sludge recovery, showing satisfactory performance in dissolving hydrocarbons. Crude oil was also used as a solvent for recovering oil from petroleum sludge, demonstrating that hydrocarbons in the petroleum sludge are completely soluble and stable in crude oil. The obtained composition can be used as a composite crude oil. The use of ionic liquids to enhance the organic solvent led to a significant reduction in the organic volume. Under optimal conditions with a ratio of 1:2.7 of petroleum sludge to solvent, centrifugation at 2300 rpm , and 1% concentration of ionic liquid,70% of water and sediments separated. The use of ionic liquid increased sepration of water and sediment 9.1 % compared to the case without ionic liquid.

محمدرضا احساني , مصطفي دهقاني مباركه

علي اصغر پاسبان , علي اكبر ميران بيگي

حميدرضا شاه وردي , علي اكبر دادخواه