Oil is a mixture of hydrocarbons, sulfur — and oxygen-containing compounds. Roughly speaking, waste from oil production and refining is the difference between the oil produced and the products derived from it. According to scientific terminology, oily waste, or oil sludge – is a multicomponent mixture, which contains petroleum products, clay, various metal oxides, sand and water. The listed components in fractions of a unit are in the ratio:
* substances of organic origin: 0,1-0,25;
* inorganic substances: 0.05 -0.3;
* water: 0.5-0.7.
Oily waste is generated at all stages of production, transportation, processing, storage and use of oil and products derived from it:
• during production, oil spills onto the ground and mixes with the soil or ground;
* accidents and accidental spills of oil products into the water (oil wastes are included in the oil-water emulsion) are possible during transportation by sea. When transported by land or through pipes, accidental oil and its products may also fall on the soil surface (a mixture of oil products and soil is formed);
* at oil refineries, wastewater containing oil waste is collected for sedimentation in special ponds and oil traps. After settling, the surface of the pond contains up to 80% oil sludge, muddy bottom — up to 1%, the middle part — up to 90%. After cleaning the tanks where oil or oil products were stored, a mixture of oil sludge with mechanical impurities, such as rust, is formed;
* oil and oil product spills are possible during use and storage (a mixture of oil products and soil is formed).
Oily waste can be divided into:
1. Liquid waste containing a lot of water and easily separated from it.
2. Gel-like waste obtained from chemical wastewater treatment. Separation of waste from water is difficult.
3. Waste containing few combustible products and practically does not separate from water.
4. Waste with a high concentration of petroleum products, requiring special methods of disposal.
Mankind uses the following methods of disposal of oily waste:
Placement in a sealed container and burial in special landfills. The method is not environmentally appropriate because of the risk of leaks and accidents. Its use can lead to environmental disasters. In addition, it is economically much more profitable to use oil waste for the second time.
Decontamination and recycling. This method includes methods:
The thermal method involves incineration of petroleum waste in furnaces, drying, pyrolysis and thermal desorption. Most commonly used combustion in bubbling, chamber, shaft, rotary kilns and fluidized bed.
This method of disposal can be called more effective along with other possible methods. Thermal utilization of oil waste and fire neutralization of contaminated water in the presence of a fuel-burning plant is economically feasible and environmentally beneficial to carry out in places of their formation.