Table Of Contents
An Alfa Laval centrifuge is an industrial centrifuge manufactured by Alfa Laval, a global standard for high-quality, reliable separation equipment. These centrifuges find various uses in all manufacturing and processing industries.
An Alfa Laval centrifuge is a sedimentation type of centrifuge that utilizes the enhanced force of gravity to separate liquids from other liquids or solids. The centrifuge features a rotating bowl assembly that exerts a centrifugal force over 8,000 times the force of gravity. This high force causes instant sedimentation of the heavy particles, causing the fluid separation from contaminating solids.
The operation of Alfa Laval centrifuges is as follows. The contaminated fluid enters the rotating bowl through a stationary tube or feed pipe. The fluid accelerates quickly to the bowl’s rotating speed, which causes centrifugal forces to act on the fluids and solids, causing the heavier solids and liquid to settle and the lighter fluid to separate and exit the bowl through an outlet chamber.
The separated solids accumulate on the bowl wall and are self-ejected through a sludge discharge mechanism.
A typical Alfa Laval centrifuge setup consists of a supply tank that holds the slurry or contaminated fluid. A transfer pump feeds this fluid to the centrifuge, which separates the fluids and solids by sedimentation under high centrifugal forces. The clear separated fluid exits the centrifuge through a discreet fluid outlet into a centrate tank.
Similarly, the heavy fluid also discharges through a heavy phase outlet into a local collection tank. The separated sludge is ejected or pushed out and falls under gravity into a collection tank below the centrifuge installation.
The diagram below shows the typical layout of the Alfa Laval centrifuge in a processing industry application.
All industries that use fluids have applications for Alfa Laval centrifuges. The following is a brief description of the industrial applications of these centrifuges.
The beverage industry typically involves separating the final product from the source of ingredients used for their production.
The commercial production of beer in large quantities requires the separation of hops and yeast from the beer. Alfa Laval has a line of beer centrifuges specifically designed to assist in the continuous production of beer. These are food-grade centrifuges with all wetted parts made of high-grade stainless steel.
These disc stack centrifuges exert a high centrifugal force to remove the small suspended yeast and organic particles to produce clear beer.
Kombucha is a relatively new beverage that ferments tea leaves and other organic ingredients. The commercial production of kombucha requires the continuous separation of organic sediment to produce a clear beverage. Filtration is not a feasible method for the large-scale production of kombucha.
A stainless steel food-grade centrifuge of the disc stack type separates the tiny organic particles from the water to produce a fine beverage.
The primary separation step in commercial juice production is the separation of pulp from fruit juice. The soft pulp particles clog up filters quickly, and therefore, filtration is not suitable for juice production.
A high-speed disc stack centrifuge uses mechanical separation to concentrate the smallest pulp particles from the juice to produce clear juice for sale.
Like fruit juice production, separating grape remnants from grape juice is a critical step in the large-scale production of wine. A self-cleaning Alfa Laval centrifuge is ideal for separating the organic grape juice from the sediment after fermentation to produce clear wine. All wine producers, including red, white, and carbonated wines, use Alfa Laval wine centrifuges to process wine.
Alfa Laval centrifuges can separate the fine suspended solids from the liquid from acceptable aluminum salts to zinc compounds. Also, being a flow-through type separator, the separation efficiency of an Alfa Laval centrifuge is consistent compared to filters that need media replacement.
A reaction between different solutions precipitates chemical ingredients. The reaction creates ingredients in the form of small or nano-suspended particles. Often, the specific gravity of these particles is much higher than the solution; therefore, they are easy to separate with an Alfa Laval disc centrifuge.
Chemical reactions use catalysts to enable the reaction process to take place. These catalysts are reusable, and their recovery is therefore necessary. Metal catalysts in the form of fine powders are quickly recovered post-reaction by an Alfa Laval industrial centrifuge. The higher specific gravity of the catalyst makes it easy to separate from the centrate under the high centrifugal force of an industrial centrifuge.
Some chemical raw ingredients are water washed to remove some undesirable contaminants. Since the contaminants are water-soluble, a water wash quickly removes the contaminants from the base chemical through a water wash.
Deionized water and the raw chemical are vigorously agitated. The DI water is then separated from the chemical by an Alfa Laval centrifuge which separates the fluids based on their specific gravity.
The pharmaceutical industry has a variety of separation applications where cultivated biological cell harvesting is a critical process. Alfa Laval stainless steel centrifuges play an important role in such extraction processes.
Medical drug manufacturing requires raw ingredients in bulk. These ingredients often require Alfa Laval centrifugal separators to separate the solid ingredients from liquid chemicals.
The commercial production of CBD oil and THC extract uses an ethanol extraction process wherein the ethanol immerses the source biomass and absorbs the cannabinoid from the biomass. The subsequent separation of biomass and ethanol purification uses Alfa Laval centrifuges for efficient extraction.
Separating bulk hemp or cannabis biomass from ethanol is the primary step in commercializing THC or CBD oil. Basket-type centrifuges have low bowl rpm and therefore have a limited centrifugal force. This reduced force prevents these centrifuges from extracting all the ethanol from the biomass.
Alfa Laval centrifuges have a much higher g-force, allowing these centrifuges to extract a high percentage of ethanol, leading to higher yields for cannabinoid processors.
The ethanol post-extraction carries waxes, lipids, chlorophyll, and other undesirable elements in the alcohol. These lipids and waxes are sticky and block downstream filter elements quickly, rendering them ineffective.
An Alfa Laval disc stack centrifuge has the high centrifugal force to separate these small, suspended particles from the ethanol. The clarified ethanol still has the dissolved cannabinoids but is clearer, reducing the load on winterization filters.
The oil and gas production processes involve Alfa Laval centrifuges at various steps of the petroleum processing process. The following are some of the process steps that utilize Alfa Laval centrifugal separators.
Crude oil storage is standard in tanks in oilfields. The water and sludge from the crude oil settle out by gravity creating tank bottoms. Tank bottoms, therefore, are a mix of water, sludge, and crude oil. Tank bottoms recovery systems featuring Alfa Laval centrifuges are the most efficient way of recovering crude oil.
Some crude oil has a high percentage of heavy metals such as cadmium, arsenic, iron, etc. Removing these metals is essential for the downstream processing of crude oil. Alfa Laval centrifuges separate the wash water from crude oil to produce oil with reduced levels of heavy metals.
Salt Water Disposals (SWD) dispose of the produced water generated during crude oil extraction. The frac water carries small amounts of crude oil recovered with the help of Alfa Laval centrifuges that separate the oil from water.
Alfa Laval centrifuges help recover industrial fluids such as hydraulic oil, reducing disposal and replenishment costs. They also increase the reliability of the presses and other equipment associated with the production.
The extrusion and stamping industry uses hydraulic oil. Alfa Laval centrifuge is well suited to remove fine wear particles and moisture (if any) from the hydraulic oil, thereby increasing the useable life of the oil and reducing equipment downtime.
Quenching is a heat treatment process typical in the metal parts production industry. The process uses a quench fluid or quench oil that is crucial for the proper heat treatment of components.
During the process, the rust and scale from the heated components contaminate the quench oil. An Alfa Laval disc stack centrifuge can remove particle contaminants down to a 1-micron level to clean the quench fluid to a reusable level.
Metalworking fluids are common throughout the manufacturing industry. These fluids act as lubricants and heat dissipators during the machining process of metals. Oil and metal particles contaminate these fluids, and removing these impurities allows for their reuse.
Machine coolant is often a water-based emulsion of oil, widely used for cooling and lubricating properties of machining metal parts. Tramp oil and fine metal particles contaminate the machining coolant. An Alfa Laval coolant centrifuge removes tramp oil and fine metal particles in a single pass producing clean, reusable coolant.
Gear hobbing, broaching, and similar metal cutting operations use cutting oil formulated for such processes. Metal particles contaminate cutting oil, and unless removed, these particles cause wear to the cutting tools and can lead to a bad surface finish of the machine components.
Alfa Laval disc stack centrifuges remove fine metal particles from cutting oil, extending s useable life.
Metal bars convert into cable wire when passed through successive dies with smaller openings. This process of drawing the metal through these dies is known as metal drawing. An oil lubricant reduces the friction between the dies and the wire. The drawing process creates small metal particles, and these particles contaminate the drawing oil.
An Alfa Laval centrifuge with a self-cleaning bowl separates these metal particles, making the oil reusable with better product quality.
Metal stamping uses a graphite-based fluid lubricant that facilitates the metal flow between dies in metal stamping operations. Over time, hydraulic oil and metal scales contaminate this lubricant. The lubricant needs to be free of impurities before reuse to ensure high product quality and equipment reliability.
An Alfa Laval three-phase disc stack centrifuge concentrates the oil out of the lubricant. It also removes solid particles and contaminants from the water-based lubricant enabling its reuse.
Fuel and lubricating oil are essential for proper functioning engines in transportation and power generation. Water, sludge, and other contaminants in fuel and lubricants can cause operating issues with engines that require clean fuel and lubricants for optimum performance.
Alfa Laval centrifuges are the most efficient devices to remove water and sludge from diesel fuel. Clean diesel fuel ensures the uninterrupted operation of diesel engines. Alfa Laval centrifuges process stored diesel fuel from tanks to keep the contaminant level to a minimum.
Large ships and power plants use fuel oil as a cheap fuel source for power generation. Manufacturers do not recommend contaminated fuel oil for their engines due to resulting operational problems and unscheduled downtime.
Alfa Laval fuel oil centrifuges continuously remove water and sludge from the fuel oil, keeping the fuel clean. Clean fuel ensures reliable engine operation and minimizes wear and tear of engines.
Engine oil or lubricant is crucial for the dependable operation of engines. With use, contaminants such as metal wear particles (from bearings), ash, and carbon get into the oil. Alfa Laval lube oil centrifuges are perfect for removing fine metal particles, ash, moisture, and other impurities from used engine oil.
Steam condensation contaminates turbine lube oil with water. In addition, metal particles from bearing wear are common solid impurities in this lube oil. Alfa Laval centrifuges separate the water and small metal particles from turbine lube oil extending its useable life.
Waste fluid refers to industrial waste oil, wastewater, waste vegetable oil (WVO), used engine oil, etc. Large volumes of water and sludge are common contaminants in waste fluids. These fluids are reusable as fuel and feedstock for biofuels if they are free of contaminants.
Industries generate large quantities of waste oil from different sources and processes. These oils are unusable beyond a specific lifecycle. These oils have high calorific value and are valuable as heating fuel.
Alfa Laval centrifugal separators separate the water and sludge from these oils enabling their use are heating fuel.
Fine sediment and trace amounts of hydrocarbons contaminate wastewater from process industries. Disposal of this wastewater is not permissible with the sediment and oil contaminants. Alfa Laval disc stack centrifuges remove the fine silt and concentrate the oil out of this wastewater, making this water suitable for disposal.
Used motor oil is perfect for blending stock for fresh motor oil, provided the ash, carbon, and moisture content is not present in used engine oil. An Alfa Laval 3-phase oil centrifuge simultaneously separates the fine ash particles and water from motor oil. This recovered motor oil is then useable as lube oil blending stock.
Biodiesel producers are the largest consumers of waste vegetable oil. However, WVO from restaurants and food processors carries water and food waste sludge and is unsuitable for biodiesel production without purification.
An Alfa Laval WVO centrifuge can process large volumes of waste vegetable oil to remove water and food waste sludge. This purification process makes the WVO a valuable resource for biodiesel producers.
Specific special applications need modifying Alfa Laval centrifuges to fit material compatibility or other process requirements. Some of these applications are listed below.
Biodiesel is not compatible with nitrile or buna rubber. Therefore, Alfa Laval centrifuges separating biodiesel from glycerin or wash water require special elastomers such as Viton for compatibility.
Centrifuge epoxy topcoats are also not compatible with biodiesel. Therefore, biodiesel centrifuge applications use Teflon-coated non-ferrous covers.
Ethanol is a flammable liquid, and therefore centrifuges processing ethanol need to be suitable for hazardous areas. Specific mechanical components within Alfa Laval centrifuges can potentially cause heat and sparks under rare conditions.
The centrifugal clutch, for example, uses friction to transmit the torque. This clutch is not suitable for hazardous applications, and therefore, the centrifuge is modified.
Food grade centrifuges need all product contact material to be stainless steel. Some Alfa Laval centrifuges have the most wetted parts made of 316 stainless steel. However, some components, such as the sludge ejection passage, are made of carbon steel.
It is possible to convert some of these stationary (non-rotating) components into stainless steel with cladding or similar coating methods.
Some highly corrosive chemicals need exotic materials such as Hastelloy for material compatibility. Special Alfa Laval centrifuges are available with all wetted parts of the Hastelloy. These centrifuges are special-order from Alfa Laval and are rare in the used centrifuge market.
Clarification of hydrofluoric acid or hydrochloric acid are examples of such applications.
Processing fluids containing abrasive solids requires special protection of the centrifuge parts in contact with the solids. The bowl body, sludge ejection ports, sludge ejection parts, etc., have special sacrificial liners. These liners wear out, protecting these expensive bowl components.
The processing of sand carrying water and crude oil are examples of such abrasive applications. Another application with abrasive particles is the processing of metal machine coolants.
Alfa Laval centrifuges provide a host of benefits when compared to other separating technologies. The main advantages, when compared to filtration, are listed below.
Unlike filters, an Alfa Laval centrifuge separates the water and solids simultaneously. This ability has significant benefits when separating liquids from other liquids and solids is needed.
Centrifuges mechanically separate the phases (solid and liquid) from each other. The separation is a continuous process, unlike filtration, which requires frequent filter media replacement.
The only ongoing operating cost of Alfa Laval centrifuges is the cost of electricity. Therefore, compared to filters, the cost of using centrifuges is considerably lower. Filters require replacement media and labor that add to operating costs.
The mesh or filter grade defines the separating efficiency of filters. An industrial centrifuge separates a wide range of sediment and therefore has a much higher separation efficiency. Alfa Laval disc stack centrifuges can separate particles down to 0.5-micron level.
The flow-through rate of filters degrades as separated particles block the pores. Alfa Laval centrifuges separate the particles mechanically; therefore, these centrifuges have no performance degradation over time.
The capacity of an Alfa Laval centrifuge is the flow rate at which the centrifuge can separate the liquid and solids phases to an acceptable level.
The capacity of an Alfa Laval centrifuge is directly proportional to its bowl size. The larger the centrifuge bowl, the higher the capacity.
Other factors also affect centrifuge processing capacity. Some of these factors are as follows:
The following table highlights the capacities of common Alfa Laval centrifuge models.
|Alfa Laval Centrifuge Model||Capacity in GPM for Different Fluids|
|Diesel||Water||Coolant||ISO 32 - Lube Oil @ 180F|
There are three main costs related to a centrifuge that the user needs to consider. They are the original equipment cost, the operating cost, and the maintenance cost.
The cost of an Alfa Laval centrifuge depends on many factors. The most crucial factor is the size or capacity of the centrifuge. The larger the centrifuge, the higher the cost. The application of the centrifuge determines the centrifuge construction and type.
For example, a sanitary application requires a food-grade centrifuge that is more expensive than a standard oil centrifuge. Centrifuges for hazardous areas require specially rated components that considerably cost the equipment.
Also, a remanufactured Alfa Laval centrifuge costs approximately 60% of a new centrifuge of similar size with similar features.
The only operating cost of the Alfa Laval centrifuge is related to the cost of electricity used by the centrifuge motor. Typically the operating cost per gallon is a fraction of a cent or thereabouts. You can see examples of operating costs of the Alfa Laval disc stack centrifuge in our detailed article about disc stack centrifuges.
The Alfa Laval centrifuge is a mechanical device that requires regular maintenance. The replacement of service kits is the primary maintenance. Service kits are available through centrifuge suppliers such as Dolphin Centrifuge or directly from Alfa Laval.
We have written a detailed article on the typical cost of Alfa Laval centrifuge maintenance.
Though Alfa Laval manufactures a few different centrifuges, the most common models are the disc stack centrifuge and the decanter centrifuge.
A disc stack centrifuge is an industrial centrifuge that can separate small sediment and immiscible liquid contaminants from a base liquid. The main feature of Alfa Laval disc stack centrifuges is the high centrifugal force of up to 10,000 Gs with a bowl RPM of over 12,000.
Another important aspect of a disc stack centrifuge is its ability to separate two insoluble fluids from each other while also separating the solids.
A disc stack centrifuge is available in two configurations. The simple version separates and retains the solids within the bowl for manual extrication. This centrifuge is suitable for liquid-liquid separation within minimal solids (< 0.05%) and is known as a manual clean centrifuge.
A self-cleaning disc stack centrifuge separates the base fluid from another insoluble fluid while also separating the solids. The design of this centrifuge allows it to self-eject the separated solids automatically while the bowl is still rotating. This centrifuge does not require manual cleaning of the solids.
A decanter centrifuge is an industrial centrifuge with a horizontal rotating bowl with a concentric conveyor rotating inside the bowl at a differential speed. The centrifugal force of the rotation causes the slides to settle at the bowl wall from where the conveyor pushes them to the solid outlet ports. The separated liquid moves and exits the bowl from the liquid end on the opposite side.
The following table shows the specifications of Alfa Laval centrifuges that are common in industrial applications.
The diagrams below show the cross-section of Alfa Laval centrifuges. The images show a disc stack centrifuge alongside a decanter centrifuge.
The disc stack bowl has a vertical orientation (rotates about a vertical axis), while the decanter bowl has a horizontal axis of rotation.
Alfa Laval centrifuges are available in different sizes. The physical size of the centrifuge is proportional to its processing capacity. The following table lists some popular Alfa Laval centrifuges, their physical characteristics, and processing capacities.
|Centrifuge Model||Centrifuge Type||Dimensions||Motor Power||Weight||Capacity|
|Alfa Laval MAB 103B-24-60||Manual Clean Disc||24" x 30" x 25" (H)||1 HP||210 Lbs||3 GPM|
|Alfa Laval MOPX 205-TGT-24||Self Clean Disc||32" x 35" x 47" (H)||4 HP||540 Lbs||12 GPM|
|Alfa Laval WHPX 513-TGD-24||Partial Eject Disc||45"x 52" x 65" (H)||15 HP||2,800 Lbs||72 GPM|
|Alfa Laval NX-309-B31||Decanter 2-Phase||60" x 36" x 40" (H)||7.5 HP||1,750 Lbs||25 GPM|
|Alfa Laval NX-314-B31||Decanter 3-Phase||75" x 36" x 45" (H)||10 HP||2,500 Lbs||40 GPM|
|Alfa Laval NX-418-B31||Decanter 2-Phase||102" x 45" x 48" (H)||20 HP||3,800 Lbs||150 GPM|
Used Alfa Laval centrifuges are a resource for potential users to get durable centrifuges with long service lives. These centrifuges are available at a lower cost and with a short delivery time. It is important to note that used centrifuges in the ‘As Is’ condition are significantly different from used centrifuges that a reputable and experienced centrifuge company remanufactures.
Used ‘As Is’ centrifuges are available from used equipment dealers. There are several caveats to buying and using these centrifuges. The most common issue with used ‘As Is’ centrifuges is the physical condition of the critical component, i.e., the centrifuge bowl.
An Alfa Laval centrifuge with a worn-out bowl is practically useless because a replacement new bowl assembly is only available from the manufacturer (Alfa Laval). The cost of the new bowl assembly is often more expensive than the used centrifuge itself.
The other point to consider is the mechanical condition of the centrifuge. An Alfa Laval centrifuge operates at high rotational speeds. Any imbalance in the rotating bowl assembly will cause excessive imbalance to the detriment of the centrifuge and, in some cases, can pose a safety risk to the operator.
Missing bowl parts and other critical components is another potential risk of buying used ‘As Is’ Alfa Laval centrifuges. Some bowl components, such as the disc stack or bowl body, are expensive, and it is often too late for the buyer to realize the cost of these components to make the centrifuge useable.
Considering all of the above-mentioned potential hazards of buying used ‘As Is’ centrifuges, we recommend against buying these centrifuges unless the buyer is highly familiar with Alfa Laval centrifuges.
The remanufacturing of Alfa Laval centrifuges is an elaborate process with multiple steps to ensure the centrifuge’s safety, reliability, and longevity. Used equipment dealers sell all types of centrifuges and other processing equipment and therefore do not have the expertise to overhaul or remanufacture the Alfa Laval centrifuge.
Some may claim to ‘remanufacture’ these centrifuges, but the potential buyer should verify such claims through previous customer references or personal inspection of the centrifuge operation.
The OEM (Alfa Laval) does sell remanufactured centrifuges, but they prefer to sell new centrifuges for apparent reasons.
We (Dolphin Centrifuge) have over 40 years of experience in remanufacturing and servicing Alfa Laval centrifuges. Our centrifuge remanufacturing process is based on the OEM recommended procedure with attention to specific details.
Our remanufacturing process starts with the base from sandblasting, double-coating, replacing all consumable parts and bearings regardless of their condition, stand-alone centrifuge testing, and complete system testing.
by Sanjay Prabhu MSME
Engineering Manager, Dolphin Centrifuge