People’s awareness of environmental protection and strict environmental standards have made it necessary to detoxify, reduce, and recycle oil sludge containing petroleum resources. At present, the oil sludge treatment technologies mainly include: oil sludge solvent extraction technology, oil sludge incineration treatment technology, oil sludge chemical hot washing technology, oil sludge thermal treatment technology, etc., in order to achieve oil-free sludge harmful, reduced, and resourced.
First. Oil sludge solvent extraction technology
Oil sludge solvent extraction technology is a physical and chemical separation technology, the core of which is the selection of organic extractant. The principle of solvent extraction technology for oil sludge is: “similar compatibility” of the solvent, mainly extracting the oil phase components in the sludge, and then distilling and fractionating the extracted solvent to realize the oil and the extraction solvent. Separation, the solvent is repeatedly used to recover oil resources. The extraction solvent currently used is mainly two kinds of organic solvent and supercritical solvent. The key of solvent extraction technology of oil sludge is the selection of extractant. To separate the oil phase in the sludge, the selected extractant must have good oil phase. Solubility, and the nature of the extractant and the oil phase should be different in the boiling range, thus ensuring the recycling of the extractant.
The solvent extraction technology of oil sludge has the advantages that the extractant can be reused, the process is simple, and most of the oil phase in the sludge can be recovered. However, most of the extractants are volatile and toxic, resulting in a large loss in the treatment process. Cost, and it will pollute the environment. At present, the research on solvent extraction technology of oil sludge mainly focuses on the development of cost-effective extractant and multi-stage treatment technology combined with other treatment processes.
Second, oil sludge incineration treatment technology
The oil sludge incineration treatment technology refers to the transportation of the oil sludge after dewatering and drying into a high-temperature combustion furnace, and the organic components are subjected to combustion reaction under oxygen-rich conditions to realize the harmlessness of the oil-containing sludge. The process of reducing the processing. The oil sludge incineration treatment technology can quickly and thoroughly treat the oil sludge harmlessly, so that the sludge volume is greatly reduced and the technical process is relatively mature, so it is considered to be one of the most practical technologies. The oil sludge incineration treatment technology is the main way for many developed countries to deal with oil sludge. The heat generated by incineration is used to generate electricity or heat, and the burned residue is used as building materials. In China, many refineries and oil fields have also put into operation a number of incineration stations for the treatment of oil sludge. For example, Yanshan Petrochemical Plant and Shengli Oilfield have built incineration stations.
Although the oil sludge incineration treatment technology can minimize the sludge and treat the sludge more thoroughly, the sludge incineration technology also has many shortcomings. The main disadvantage is that the incineration equipment occupies a large area, the investment is large, the operation is complicated, and the incineration the flue gas generated in the process contains dioxins, a large amount of SO2, NOx and other gases as well as a large amount of dust, which may cause secondary pollution if not handled properly.
Third, oil sludge chemical hot wash technology
The chemical hot-washing technology of oil sludge has two kinds of treatment processes: low-temperature hot washing and high-temperature hot-washing according to the temperature. Generally, the processing temperature below 100 °C is called low-temperature hot washing, and the processing higher than 100 °C is called Hot wash at high temperature. The chemical hot-washing technology of oil sludge is mainly to add a certain amount of chemical reagents (alkali and a small amount of surface activator) to the oil sludge for repeated washing at a certain temperature, and then to realize oil and slag by means of a device such as swirling or air floating. Separation, adding a demulsifier to the oil-water phase, destroying the oil-water emulsion which is stable and recovering the oil resources therein. Compared with high-temperature hot-washing, low-temperature hot-washing has the advantages of less energy consumption and lower processing cost, but the waxy and asphaltene gums in the oil-containing sludge are not completely removed, resulting in the oil sludge after treatment being insufficient. Emission Standards. The chemical hot-washing technology of oil sludge is currently used for floor sludge with a large slag rate, and most of them are treated with hot alkaline water to treat such sludge.
Forth. Oil sludge thermal treatment technology
The oil sludge pyrolysis treatment technology was first applied to the dry distillation of coal. It was introduced in the 1990s for the recycling of solid waste. In recent years, the pyrolysis treatment technology of oil sludge has developed rapidly, and it is considered to be the most advantageous technology for resource treatment of oil sludge. The oil sludge pyrolysis treatment technology is to heat the sludge to a certain temperature in an environment of isolating oxygen, and to carry out complicated chemical reactions, including thermal cracking reaction and thermal condensation reaction, among various hydrocarbons, waxes and colloidal asphaltenes. In order to realize the harmless, reduced and resource-based treatment technology of oil sludge.
The processing conditions of the oil sludge pyrolysis treatment technology are generally atmospheric pressure, so the requirements on the equipment are not high, and no high-pressure material is required, which greatly reduces the investment cost; and the equipment is relatively simple, and the processed pyrolysis product has a high The use of value reduces operating costs. The toxic and harmful gases generated during the pyrolysis treatment of oil sludge are less, and the residue after treatment can achieve oil content ≤3‰. Although the oil sludge pyrolysis treatment technology has many advantages, there are still many problems. The gas generated during the pyrolysis process often has a foul odor. If it is not handled properly, it will cause secondary pollution. The recovered oil contains more impurities, and the raw materials are different. Residues that can cause high levels of heavy oil to become unusable are still classified as hazardous.
The oil sludge pyrolysis gasification unit independently researched and developed by our institute has the advantages of precise automation control, safe and reliable system operation, high dry distillation efficiency, etc., through the resource treatment of oil sludge, gas-liquid solid three-phase separation, extraction of oil sludge oil products to achieve a win-win situation for resource recovery and environmental protection. The sludge decontamination gasification unit will become a general trend of sludge treatment for the harmless, resource treatment and utilization of oil sludge.