Throughout the process of extracting, transporting, and refining crude oil and other petroleum products, it is possible for the oil to become contaminated with both solid and liquid pollutants, such as sediment and water. For instance, oily sludge is an oily solid waste that can be recycled and reclaimed for its value as an oil product. Any excess contamination in a petroleum product can result in an end product that is not usable. Additionally, disposing of contaminated petroleum products in an environmentally responsible manner can be a challenge.
Excess sediment and water are commonly found in crude oil production, damaging the quality of the final petroleum products. These unwanted byproducts are present in varying proportions of oil, water, and solids, often in emulsified states. As a result, all products with high levels of sediment and water become unsaleable and non-disposable.
To effectively use this dormant oil/water emulsion, it is crucial to reduce the level of sediment and water to an acceptable threshold. The extraction separation, quenching, high temperature tempering-mechanical dehydration, thermal desorption, and biological treatment methods are commonly used to recover oil, both domestically and internationally. However, the composition of oil products that require treatment from different oil fields and refineries is complex, with varying oil concentrations. Therefore, it is important to precisely utilize and adjust the oil-water-solid three-phase interface of the equipment according to the feed concentration. Recognizing the issue that existing three-phase horizontal screw centrifuges used in mechanical centrifugal dehydration are unable to accurately adjust the oil-water interface, this paper proposes a targeted solution in the form of a specialized three-phase horizontal screw centrifuge.
Analysis of CFD calculation results of annular liquid distribution plate pipe flange type drainage structure
A model of the traditional three-phase horizontal screw centrifuge, based on a three-dimensional flow domain, was established. Using Gambit meshing and Fluent boundary condition setting, the velocity inlet was defined as the inlet, while the three outlets (solid phase outlet and overflow oil and water outlets) were defined as outflow (free outflow). The fluid region was also defined as the flow domain. For turbulence modeling, the RNG k-ε equation was utilized, and the standard wall function method was used for near-wall treatment. Calculation was performed using the separated implicit and SIMPLE methods. In the Euler-Euler model, the Mixture multiphase flow model was used, with the water phase as the initial phase and the oil and solid phases as second-order phases. All three phases (oil, water, and solid) were treated as incompressible fluids. The simulation assumed that the entire flow domain was filled with fluid (excluding the fourth phase of air), meaning that the free liquid.