Three Phase Liquid Liquid Solid Centrifuge

Three-phase separation is one of the most challenging unit operations in industrial processing, requiring the simultaneous separation of two immiscible liquids (oil and water, or two solvents) and a solid phase from a single feed stream. Applications for three-phase separation span numerous industries including crude oil desalting and dehydration (separation of oil, water, and solids from crude oil), oil sludge treatment (recovery of oil, water, and solids from refinery waste), biodiesel glycerin separation (separation of biodiesel, glycerin, and catalyst solids), solvent extraction processes (recovery of two solvent phases plus solids), and petrochemical refining. Traditional three-phase separation methods typically require multiple pieces of equipment in series: gravity settling tanks for oil-water separation followed by centrifuges or filters for solids removal. This multi-step approach requires large footprints, long residence times, multiple unit operations, and high capital and operating costs. Our Three Phase Liquid Liquid Solid Centrifuge has been specifically engineered to overcome these limitations through high-speed, continuous three-phase centrifugation that simultaneously separates oil, water, and solids in a single pass, dramatically simplifying process flow, reducing equipment footprint, and improving separation efficiency. The disc stack or decanter design with specialized weir plate configuration provides simultaneous separation of three phases based on their density differences: the lightest liquid phase (oil or light solvent, specific gravity 0.7-0.95), the intermediate liquid phase (water or heavy solvent, specific gravity 1.0-1.2), and the densest solid phase (specific gravity 1.5-3.0). The high-G design (up to 10,000 x g for disc stack, up to 4,000 x g for decanter) provides the driving force needed to separate phases with small density differences (as low as 0.02-0.05 g/mL between oil and water). The adjustable weir plates allow precise control of the oil-water interface position, optimizing separation of both liquid phases simultaneously. The continuous solids discharge mechanism (partial ejection for disc stack, scroll conveyor for decanter) removes accumulated solids without interrupting operation. All product-contact surfaces are manufactured from corrosion-resistant materials (SUS316L, Duplex stainless steel, Hastelloy, titanium) to handle the aggressive chemical environment of oil-water-solids mixtures. The system is fully enclosed with inert gas purging for flammable atmospheres and available with explosion-proof (ATEX/IECEx) certification. The three-phase centrifuge has been validated for a wide range of applications including crude oil desalting (removal of brine water and sand from crude oil), refinery oil sludge treatment (recovery of oil, water, and solids from tank bottoms), biodiesel glycerin separation (separation of biodiesel, glycerin, and catalyst residues), produced water treatment (removal of oil and solids from produced water), solvent extraction (separation of two immiscible solvents plus solids), and chemical plant waste treatment. For each application, the operating parameters including G-force, feed rate, weir plate configuration, interface position, and solids discharge interval can be optimized to achieve maximum recovery of all three phases. The control system continuously monitors key parameters including bowl speed, feed rate, oil-water interface position (detected by conductivity or optical sensor), discharge oil quality (BS&W), and solids discharge consistency, providing real-time feedback for process optimization. For crude oil applications, the centrifuge can reduce basic sediment and water (BS&W) from 2-10% to <0.2-0.5% while recovering >99% of oil. For biodiesel applications, the centrifuge separates biodiesel (0.88 sg), glycerin (1.26 sg), and catalyst solids in a single pass, producing biodiesel with <0.02% free glycerin.

The disc stack centrifuge design with adjustable weir plates is the preferred configuration for most three-phase applications, particularly when the solids content is low to moderate (0.1-5% solids) and fine separation of liquid phases is required. The disc stack consists of precision-engineered conical discs stacked vertically, with the top disc modified to create separate discharge paths for light and heavy liquid phases. As the three-phase mixture enters the bowl through the low-shear inlet, it is accelerated to bowl speed. Centrifugal forces up to 10,000 x g separate the phases based on density: the light liquid phase (oil) migrates inward toward the center, the intermediate liquid phase (water) forms a layer between the oil and solids, and the heavy solid phase is driven outward to the bowl wall. The light liquid discharges over adjustable weir plates at the top of the bowl, while the heavy liquid discharges through a separate set of weir plates. The solids accumulate in the solids holding space and are ejected periodically through the partial ejection mechanism (50-300 ms cycles). The position of the oil-water interface is controlled by the relative heights of the oil and water weir plates; the interface should be positioned between the disc stack outlet and the solids space for optimal separation. For crude oil desalting, the interface is typically set at 50-60% of the bowl radius. For biodiesel separation, the interface is set at 30-40% of the radius due to the larger density difference. For applications with higher solids content (5-20% solids), a three-phase decanter centrifuge may be preferred. The decanter features a scroll conveyor that continuously discharges solids, while weir plates at the opposite end separate light and heavy liquids. The decanter configuration is ideal for oil sludge treatment, where solids content can exceed 20%. For both configurations, the three-phase centrifuge eliminates the need for separate desalters, separators, and sludge tanks, reducing equipment count by 50-75% and footprint by 60-80%. The simultaneous three-phase separation also reduces product loss, as the sharp phase boundaries prevent oil from being lost in the water phase or water from being carried over into the oil phase.

Our Three Phase Liquid Liquid Solid Centrifuge incorporates several advanced features specifically designed for three-phase applications. The feed system includes a low-shear inlet and automated flow control. The control system provides comprehensive monitoring and automation, built around a Siemens S7-1500 or Allen-Bradley ControlLogix PLC with a 15-inch full-color touchscreen HMI. The user interface presents key parameters including bowl speed, feed rate, interface position, oil BS&W, water oil content, and solids discharge interval. The system supports full recipe management, remote monitoring, and data logging. The combination of robust mechanical design and advanced three-phase separation capability makes our centrifuge the preferred choice for oil, petrochemical, and biodiesel processing worldwide.