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'''Centrifugation''' is a mechanical separation process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The more dense components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Chemists and biologists may increase the effective gravitational force of the test tube so that the precipitate (pellet) will travel quickly and fully to the bottom of the tube.
{{Infobox technology
| Feedstock = All materials
| Category = [[Pre-processing]] ([[Pre-processing#Separation_technologies|Separation technologies]]), [[Post-processing]] ([[Post-processing#Separation_technologies|Separation technologies]])
| Product = Separated products
|Name= Centrifugation}}
<onlyinclude>'''Centrifugation''' is a mechanical separation process which involves the use of the centrifugal force to separate particles from a solution or liquids of different densities according to particle size, shape, density, viscosity and rotor speed. The more dense components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Next to the separation of solids from liquid, it is possible to obtain separation between two liquids of different densities as well, given that the density difference is large enough.</onlyinclude>
 
==Feedstock==
[[File:Centrifuga_Hermle_2.jpg|thumb|upright|Laboratory centrifuge]]
[[File:How centrifuge works.png|thumb|Testtube with precipitate (pellet) and supernatant after centrifugation|150x150px]]
=== Origin and composition ===
The centrifugation method is used to separate two miscible substances. The most common application is the separation of solids from highly concentrated suspensions, which is used in the treatment of sewage sludges for dewatering where less consistent sediment is produced.  In the food industries, special centrifuges can process a continuous stream of particle-laden liquid.
 
=== Pre-treatment ===
For a centrifugation, in general no specific pre-treatment is needed since it is used to separate different fractions within a process chain. Sometimes it is combined with other separation technologies like [[filtration]].


==Input==
The centrifugation method is used to separate two miscible substances.  The most common application is the separation of solid from highly concentrated suspensions, which is used in the treatment of sewage sludges for dewatering where less consistent sediment is produced.  In the food industries, special centrifuges can process a continuous stream of particle-laden liquid.
==Process and technologies==
==Process and technologies==
There is a correlation between the size and density of a particle and the rate that the particle separates from a heterogeneous mixture, when the only force applied is that of gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a centrifuge does, the separation of the particles is accelerated. This is ideal in industrial and lab settings because particles that would naturally separate over a long period of time can be separated in much less time.
There is a correlation between the size and density of a particle and the speed at which the particle separates from a heterogeneous mixture, when the only force applied is gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a centrifuge does, the separation of the particles is accelerated. This way, in industrial and lab settings, particles that would naturally separate over a long period of time can be separated much faster.
 
The centrifugation speed is specified by the angular velocity, usually expressed as revolutions per minute (rpm), or acceleration expressed as ''g''. The conversion factor between rpm and ''g'' depends on the radius of the centrifuge rotor. The particles' settling velocity in centrifugation is a function of their size and shape, centrifugal acceleration, the volume fraction of solids present, the density difference between the particle and the liquid, and the viscosity. 
 
The sedimentation of particles can be explained by Stoke's law. The equation can be used to calculate the velocity of sedimentation based on five parameters:
[[File:Stokes-equation.jpg|center]][[File:HD.16.088 (12523557255).jpg|alt=Picture showing basket centrifuge for the continuous collection of algae in 1966|thumb|Basket centrifuge for the continuous collection of algae in 1966|312x312px]]From the Stokes equation, five important behaviours of particles can be explained: 
 
#The rate of particle sedimentation is proportional to the particle size
#The sedimentation rate is proportional to the difference in density between the particle and the medium.
#The sedimentation rate is zero when the particle density is the same as the medium density.
#The sedimentation rate decreases as the medium viscosity increases.
#The sedimentation rate increases as the gravitational force increases.
 
=== Disc-stack centrifugation ===
Disc-stack centrifugation is used for removing suspended solids from a liquid having a lower specific gravity than the solids. The solids content of the feed is usually in the range of 0.1-10 V/V%.
=== Basket centrifugation ===
Basket centrifuges are often called centrifugal filters or clarifiers. The basket centrifuge uses centrifugal force to generate a pressure which forces the liquid through the caked solids, the filter cloth, the backing screen, and finally the basket perforations. The filter cloth retains the solid particles inside the rotating basket while the permeating liquid is continuously discharged.
[[File:Solid Bowl Centrifuge 3.png|alt=Solid Bowl Centrifuge – A drawing showing the principle|thumb|Solid Bowl Centrifuge]]
 
=== Solid bowl centrifugation ===
The Solid Bowl centrifugation principle is schematically shown in the picture on the right. "Solid bowl centrifuges (SBCs), also known as decanter centrifuges, are widely used for various solid-liquid separation tasks, owing to its high-efficiency, small machine footprint and good continuity in production. In the SBC, once the slurry is fed through the centre-positioned feed pipe, solids can rapidly settle onto the drum wall and these settled solids are further dewatered on the conical section of the SBC before being discharged from the product chute. The clarified liquid, so-called effluent, overflows through the bowl weir."<ref>{{Cite journal|title=Measurement of solids concentration in aqueous slurries for monitoring the solids recovery in solid bowl centrifugation|year=2021-08-15|author=Changzhi Bai, Hangil Park, Liguang Wang|journal=Minerals Engineering|volume=170|page=107068|doi=10.1016/j.mineng.2021.107068}}</ref>
 
==Products ==
The remaining liquid is called supernatant or supernate. The solids or pellets and the supernatant can be the final product or can be further processed.
 
=== Post-treatment===
The post-treatment of the precipitate and/or the supernatant is depending on the next steps within the production chain. A typical next step is to dry the solids for further processing.


The rate of centrifugation is specified by the angular velocity usually expressed as revolutions per minute (RPM), or acceleration expressed as ''g''. The conversion factor between RPM and ''g'' depends on the radius of the centrifuge rotor. The particles' settling velocity in centrifugation is a function of their size and shape, centrifugal acceleration, the volume fraction of solids present, the density difference between the particle and the liquid, and the viscosity.
== Technology providers==
{| class="wikitable sortable mw-collapsible"
|+'''Technology comparison'''
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Company name
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Country
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Technology subcategory
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Technology name
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| TRL
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Capacity [L/h]
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Processable volume [L]
! class="cd-text-darkgreen" style="vertical-align:{{{va|bottom}}}"| Relative centrifugal force [g]
! class="cd-text-darkgreen" style="{{writing-mode|s2}};vertical-align:{{{va|bottom}}}"| Feedstock: Food waste
! class="cd-text-darkgreen" style="{{writing-mode|s2}};vertical-align:{{{va|bottom}}}"| Feedstock: Garden & park waste
|-
! style="height:1.8em;"|
!
!
!
!
!
!
!
!
!
|-
| [[Centrifugation#Alfa_Laval|Alfa Laval]]
| Sweden
| -
| AlfaPure S2-S7
| -
| 900-7000
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Alfa_Laval_2|Alfa Laval]]
| Sweden
| -
| Alfie 200
|
| 230-280
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Ecofast|Ecofast]]
| Italy
| -
| DeHydra SC1B
| -
| 300
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Flottweg|Flottweg]]
| Germany
| -
| SEDICANTERS® S6E-3
| -
| 50000
| -
| 5000
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Imperial_Machine_Company_Ltd._.28IMC.29|Imperial Machine Company Ltd. (IMC)]]
| United Kingdom
| -
| -
| -
| 700
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Rendisk|Rendisk]]
| The Netherlands
| -
| -
| -
| 450
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|-
| [[Centrifugation#Tidy_Planet|Tidy Planet]]
| United Kingdom
| -
| DeHydra Super Compact
| 9
| 700
| -
| -
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
| class="cd-background-lightgreen cd-text-darkgreen" style="text-align:center" |●
|}


==Output==
=== Alfa Laval ===
The remaining liquid that lies above the precipitate is called a supernatant or supernate.
{{Infobox provider-centrifugation|Company=Alfa Laval Corporate AB|Country=Sweden
==Technology providers==
|Contact=  
===ABC===
|Webpage=https://www.alfalaval.com|Image=Logo Alfa Laval.png
describe the company, here is an example
|Technology name= AlfaPure|Feedstock=water and oil-based liquids|Product=seperated fractions
|TRL=commercial|Capacity=900-2000,<br/> 600-3000,<br/> 5000–7000|Temperature=0-80 (15-100)
}}


''ABC was founded in 20... 12 by KNN and Syncom, in collaboration with the university of Groningen, Netherlands. The company is a technology provider developing chemical recycling technologies for different feedstocks including non-food bio- and plastics waste. In 2018 a pilot plant with the capability to process biomass and plastic waste was set up at the Zernike Advanced Processing (ZAP) Facility. The company is now focused on setting up their first commercial plant with a capacity of 20,000 to 30,000 tonnes. The investing phase B was recently completed, with the last investment phase in 2019 the financial requirements are fulfilled to complete the commercialisation activities to build the plant which is expected for 2023.''
Alfa Laval is a leading global provider of first-rate products in the areas of heat transfer, separation and fluid handling. With these as its base, Alfa Laval aims to help enhance the productivity and competitiveness of its customers in various industries throughout the world. We define their challenges and deliver sustainable products and solutions that meet their requirements – mainly in energy, the environment, food and the marine industry.


describe their technology, here is an example
* [https://www.alfalaval.com/globalassets/documents/products/separation/centrifugal-separators/disc-stack-separators/alfapures2_productleaflet_efu00129en.pdf Technical Details AlfaPure S2]
* [https://www.alfalaval.com/globalassets/documents/products/separation/centrifugal-separators/disc-stack-separators/alfapures3_productleaflet_efu00185en.pdf Technical Details AlfaPure S3]
* [https://www.alfalaval.com/globalassets/documents/products/separation/centrifugal-separators/separators/alfapure/product_leaflet_alfapure_s7_separator_and_system_en.pdf Technical Details AlfaPure S7]
 
=== Alfa Laval ===
{{Infobox provider-centrifugation|Company=Alfa Laval Corporate AB|Country=Sweden
|Contact=
|Webpage=https://www.alfalaval.com|Image=Logo Alfa Laval.png
|Technology name=Alfie|Feedstock=from water-based industrial fluids, coolants|Product=seperated / cleaned fractions
|TRL=commercial|Capacity=230-280|Temperature=5–50
}}
 
Alfa Laval is a leading global provider of first-rate products in the areas of heat transfer, separation and fluid handling. With these as its base, Alfa Laval aims to help enhance the productivity and competitiveness of its customers in various industries throughout the world. We define their challenges and deliver sustainable products and solutions that meet their requirements – mainly in energy, the environment, food and the marine industry.
 
Alfie is a simple to use separator: Turnkey, portable, small footprint, centrifugal disc stack separators that remove contaminating oil, grease and solid particles from water-based industrial fluids such as coolants and wash liquids.
 
* [https://www.alfalaval.com/globalassets/documents/products/separation/centrifugal-separators/disc-stack-separators/product-leaflet/efu00038en_lowres-3.pdf Technical Details Alfie 200]
 
===Ecofast===
{{Infobox provider-centrifugation|Company=Ecofast Italia S.r.l.|Country=Italy|Webpage=www.ecofast.eu|Technology name=DeHydra SC1B|Rotor type=Pump rotor|Capacity=300 kg/h|Relative centrifugal force=930 rpm|Feedstock=Food waste|Product=De-watered food waste}}
 
Ecofast Italia is an innovative SME that designs and manufactures equipment to compact food waste in professional catering and catering. The use of our machines makes the kitchen more hygienic and clean and helps to improve the safety of the working environment. Less waste to be disposed of, less waste in landfills, less greenhouse gases produced for their collection.
 
From the beginning, the company’s activity has been characterized by a more marked technical connotation, carrying out, first in Italy, not only important tests in the use of food waste disposes, but an innovative research and development activity to the invention of new patents for new products/technologies in order to enhance a more sustainable and economic management of food waste. Ecofast Italia S.r.l. – Environmental Technology was established in Milan on November 23th 1998, at first to import and distribute food waste disposers for domestic and professional users, in Europe.
 
The DEHYDRA SC1 can be placed in the washing area or in cleaning areas of canteens and/or restaurants where it is required to dispose of up to 150 kgs per hour of food waste. Our compact food waste reduction machine is a stainless steel standalone de-watering solution, made up of a hydro extractor, and a centrifugal press which separates the liquid from the solid component. The DeHydra dewater apparatus is the only self-cleaning de-watering system that can be fitted with wastewater re-circulation.
 
===Flottweg===
{{Infobox provider-centrifugation|Company=Flottweg SE|Country=Germany|Webpage=https://www.flottweg.com/|Technology name=SEDICANTERS® S6E-3|processablevolume=Up to 50 m3/h|Rotor type=Flottweg Simp Drive®|Capacity=25 - 40 Mt/h|Relative centrifugal force=3650 rpm, 5000 x g|Temperature=Up to 100|Feedstock=Biomass, yeast suspensions, protein suspensions, fermentation broths etc.|Product=Clarification, dewatering, thickening of sludge, separation of three-phase mixtures, classification of solids, sorting of solids by density}}
 
Flottweg has their headquarters in Vilsbiburg, Germany and has been manufacturing centrifuges, belt presses, and processing systems for mechanical solid-liquid separation for more than 60 years. This technology encompasses core functions in many industrial sectors, i.e. clarifying liquids, separating liquid suspensions and concentrating and dewatering solids. Our company has grown to more than 750 employees and we achieve sales of 152 Million Euro, with an export rate of more than 85 %.
 
Flottweg Sedicanters® are used for the continuous separation of fine solids from liquids with the solids forming a soft to flowing sediment. Flottweg Sedicanters® are preferably used in cases where the solids are too fine to be effectively processed in a decanter and the sediment cannot be easily discharged from the decanter due to its soft consistency. Flottweg’s range of Sedicanter® sizes includes machines with capacities up to 50 m3 /h (220 gallons per minute).
 
===Imperial Machine Company Ltd. (IMC)===
{{Infobox provider-centrifugation|Company=Imperial Machine Company Ltd. (IMC)|Country=United Kingdom|Webpage=https://www.lincat.co.uk/index.php?p=brands/imc|Capacity=700 kg/h|Feedstock=Soft waste (plate waste, vegetable peelings, meet and fish scraps), medium waste (small pork and chicken bones, vegetables and fruit), tough waste (all red meat bones, cauliflower stalks and fish skins).|Product=Dewatered and macerated food waste.}}
 
Imperial Machine Company (IMC) has their headquarters in Lincoln, UK and has been engineering catering solutions for more than 110 years. We have designed, installed and supported catering products for foodservice operations for generations; a fact we at IMC are immensely proud of.
 
Food waste typically represents around 40% of total commercial catering waste. It is difficult and costly to process and dispose of this efficiently. Of this 40%, approximately 77% is liquid. WasteStation grinds the food waste into fine particles, which are fed directly into a built-in dewatering system, or for where space in the kitchen is limited, a remote dewatering system. Through centrifugal action, excess liquid is forced out. The resulting solid fraction of the food waste is collected in small, easily managed, lidded bins, ready for onward processing.
 
===Rendisk===
{{Infobox provider-centrifugation|Company=Rendisk B.V.|Country=The Netherlands|Capacity=450 kg/h|Feedstock=Food waste|Product=De-watered food waste|Webpage=https://www.rendisk.com/}}
 
Founded in Ruurlo, the Netherlands in 1973, Rendisk has grown to become a leader with the brand Rendisk in dishwashing logistics and food waste solutions for professional kitchens in locations around the world. We support kitchen teams with smart logistic solutions for dishwashing and groundbreaking solutions for processing your kitchen waste. All our efforts are focused on making work in the kitchen easier, more efficient and more sustainable. But always with care for the local and world environment most in mind.
 
The Rendisk Solus Eco is our most compact solution for food waste treatment and can rapidly deal with all kinds of organic food waste. Unique to the Solus Eco is that it’s a standalone unit. Thanks to its innovative technique it has an extremely small footprint and therefore fits in any kitchen or garbage room, but still can reduce your food waste massively.
 
The Rendisk Solus Eco is a clean and easy to use waste solution for restaurants and business restaurants, universities, hospitals, hotels, maritime areas and locations like holiday and entertainment parks. It’s the perfect food waste solution for anyone who believes in sustainability and efficiency. You simply load the food waste into the hopper. It is then ground and dehydrated using a special centrifugal technique. It’s due to this technique that the Solus Eco can reduce your food waste by up to 80%, lowering your removal cost dramatically. The Rendisk water management system reduces the water consumption considerably comparing with similar systems. Our smart technology reuses the water in the system allowing for a significant reduction in washed water.
 
===Tidy Planet===
{{Infobox provider-centrifugation|Company=Tidy Planet Limited|Country=United Kingdom|Image=TidyPlanetLogo.jpg|Contact=Huw Crampton|Webpage=https://tidyplanet.co.uk/|Technology name=DeHydra Super Compact|TRL=9|Capacity=700 kg/h|Feedstock=Food waste|Product=Ground and de-watered food waste|Rotor type=Screw system encapsulated in a stainless steel mesh with 1.5 mm perforations|processablevolume=700 - 1400 L/h|Temperature=5 - 60}}
 
Tidy Planet present the widest range of on-site food waste recycling products on the market, tested and manufactured to the highest quality standards here in the UK – tackling on-site, commercial food waste volumes ranging from 20kg to 20 tonnes of food waste per day.
 
The Dehydra Food Waste Dewatering system has the capacity to reduce food waste volume by up to 80% and weight by up to 50%, through a process of shredding and then using a centrifuge to separate the liquid wastes, such as sauces, soups and juices. The greatly reduced volume of finely shredded particles of food are captured and deposited into a bin in the footprint of the unit and the weighty liquid effluent disposed to sewer.
 
==Open access pilot and demo facility providers==
[https://biopilots4u.eu/database?field_technology_area_data_target_id=105&field_technology_area_target_id%5B70%5D=70&field_contact_address_value_country_code=All&field_scale_value=All&combine=&combine_1= Pilots4U Database]


''The technology is based on an Integrated Cascading Catalytic Pyrolysis (ICCP) process, being able to produce aromatics including benzene, toluene, and xylene (BTX) as well as light olefins from low grade biomass and plastics waste. This technology utilises catalytic cracking in a two-step process at temperatures between 450- 850 °C. In the first step the feedstock material is vaporised via thermal cracking. The pyrolysis vapours are then directly passed into a second reactor in which they are converted into aromatics by utilising a zeolite catalyst which can be continuously regenerated. Finally, the products are separated from the gas via condensation. An ex situ approach of catalytic conversion has several advantages such as the protection of the catalyst from deactivation/degradation expanding its lifetime, a greater variety of feedstock, and a precise adjustment of process conditions (e.g. temperature, catalyst design, and Weight Hourly Space Velocity (WHSV) in each step for improved yields. In current pilot plant with 10 kg h-1 feed capacity for either waste plastics or biomass, final design details are established, which will be include in the running engineering activities for the commercial plant.''
==Patents==
==Patents==
{{Infobox provider-pyrolysis
Currently no patents have been identified.
| Company = ABC
| Webpage = https://biobtx.com/
| Location = The Netherlands
| Business-Model = Licensing
| TRL = 5-6
| Patent = WO2017222380A1
| Technology name = Integrated Cascading Catalytic Pyrolysis (ICCP) technology
| Technology category = Catalytic Pyrolysis, two-step
| Feedstock = Biomass (liquid, solid), wood pulp lignin residues, used cooking oil
| Product = Benzene, toluene, xylene, aromatics, light gases
| Reactor = Fluidised sand bed, fixed bed
| Heating = Fluidised sand bed
| Atmosphere = Inert
| Pressure = 1-4
| Capacity = 10
| Temperature = 450-650
| Catalyst = Zeolite
| Other = Unknown
}}


==References==
==References==
*[[:en:Centrifugation|Centrifugation]] in Wikipedia
*[[:en:Centrifuge|Centrifuge]] in Wikipedia
[[Category:Pre-processing]]
[[Category:Post-processing]]
[[Category:Technologies]]

Latest revision as of 10:19, 7 March 2023

Technology
21-04-27 Tech4Biowaste rect-p.png
Technology details
Name: Centrifugation
Category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
Feedstock: All materials
Product: Separated products

Centrifugation is a mechanical separation process which involves the use of the centrifugal force to separate particles from a solution or liquids of different densities according to particle size, shape, density, viscosity and rotor speed. The more dense components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Next to the separation of solids from liquid, it is possible to obtain separation between two liquids of different densities as well, given that the density difference is large enough.

Feedstock

Laboratory centrifuge
Testtube with precipitate (pellet) and supernatant after centrifugation

Origin and composition

The centrifugation method is used to separate two miscible substances. The most common application is the separation of solids from highly concentrated suspensions, which is used in the treatment of sewage sludges for dewatering where less consistent sediment is produced. In the food industries, special centrifuges can process a continuous stream of particle-laden liquid.

Pre-treatment

For a centrifugation, in general no specific pre-treatment is needed since it is used to separate different fractions within a process chain. Sometimes it is combined with other separation technologies like filtration.

Process and technologies

There is a correlation between the size and density of a particle and the speed at which the particle separates from a heterogeneous mixture, when the only force applied is gravity. The larger the size and the larger the density of the particles, the faster they separate from the mixture. By applying a larger effective gravitational force to the mixture, like a centrifuge does, the separation of the particles is accelerated. This way, in industrial and lab settings, particles that would naturally separate over a long period of time can be separated much faster.

The centrifugation speed is specified by the angular velocity, usually expressed as revolutions per minute (rpm), or acceleration expressed as g. The conversion factor between rpm and g depends on the radius of the centrifuge rotor. The particles' settling velocity in centrifugation is a function of their size and shape, centrifugal acceleration, the volume fraction of solids present, the density difference between the particle and the liquid, and the viscosity.

The sedimentation of particles can be explained by Stoke's law. The equation can be used to calculate the velocity of sedimentation based on five parameters:

Stokes-equation.jpg
Picture showing basket centrifuge for the continuous collection of algae in 1966
Basket centrifuge for the continuous collection of algae in 1966

From the Stokes equation, five important behaviours of particles can be explained:

  1. The rate of particle sedimentation is proportional to the particle size
  2. The sedimentation rate is proportional to the difference in density between the particle and the medium.
  3. The sedimentation rate is zero when the particle density is the same as the medium density.
  4. The sedimentation rate decreases as the medium viscosity increases.
  5. The sedimentation rate increases as the gravitational force increases.

Disc-stack centrifugation

Disc-stack centrifugation is used for removing suspended solids from a liquid having a lower specific gravity than the solids. The solids content of the feed is usually in the range of 0.1-10 V/V%.

Basket centrifugation

Basket centrifuges are often called centrifugal filters or clarifiers. The basket centrifuge uses centrifugal force to generate a pressure which forces the liquid through the caked solids, the filter cloth, the backing screen, and finally the basket perforations. The filter cloth retains the solid particles inside the rotating basket while the permeating liquid is continuously discharged.

Solid Bowl Centrifuge – A drawing showing the principle
Solid Bowl Centrifuge

Solid bowl centrifugation

The Solid Bowl centrifugation principle is schematically shown in the picture on the right. "Solid bowl centrifuges (SBCs), also known as decanter centrifuges, are widely used for various solid-liquid separation tasks, owing to its high-efficiency, small machine footprint and good continuity in production. In the SBC, once the slurry is fed through the centre-positioned feed pipe, solids can rapidly settle onto the drum wall and these settled solids are further dewatered on the conical section of the SBC before being discharged from the product chute. The clarified liquid, so-called effluent, overflows through the bowl weir."[1]

Products

The remaining liquid is called supernatant or supernate. The solids or pellets and the supernatant can be the final product or can be further processed.

Post-treatment

The post-treatment of the precipitate and/or the supernatant is depending on the next steps within the production chain. A typical next step is to dry the solids for further processing.

Technology providers

Technology comparison
Company name Country Technology subcategory Technology name TRL Capacity [L/h] Processable volume [L] Relative centrifugal force [g] Feedstock: Food waste Feedstock: Garden & park waste
Alfa Laval Sweden - AlfaPure S2-S7 - 900-7000 - - ● ●
Alfa Laval Sweden - Alfie 200 230-280 - - ● ●
Ecofast Italy - DeHydra SC1B - 300 - - ● ●
Flottweg Germany - SEDICANTERS® S6E-3 - 50000 - 5000 ● ●
Imperial Machine Company Ltd. (IMC) United Kingdom - - - 700 - - ● ●
Rendisk The Netherlands - - - 450 - - ● ●
Tidy Planet United Kingdom - DeHydra Super Compact 9 700 - - ● ●

Alfa Laval

Centrifugation provider
General information
Company: Alfa Laval Corporate AB Logo Alfa Laval.png
Country: Sweden
Contact:
Webpage: https://www.alfalaval.com
Technology and process details
Technology name: AlfaPure Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: commercial Capacity: 900-2000,
600-3000,
5000–7000 l·h-1
Processable volume: L Relative centrifugal force: g
Rotor type: Temperature: 0-80 (15-100) °C
Other:
Feedstock and product details
Feedstock: water and oil-based liquids Product: seperated fractions

Alfa Laval is a leading global provider of first-rate products in the areas of heat transfer, separation and fluid handling. With these as its base, Alfa Laval aims to help enhance the productivity and competitiveness of its customers in various industries throughout the world. We define their challenges and deliver sustainable products and solutions that meet their requirements – mainly in energy, the environment, food and the marine industry.

Alfa Laval

Centrifugation provider
General information
Company: Alfa Laval Corporate AB Logo Alfa Laval.png
Country: Sweden
Contact:
Webpage: https://www.alfalaval.com
Technology and process details
Technology name: Alfie Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: commercial Capacity: 230-280 l·h-1
Processable volume: L Relative centrifugal force: g
Rotor type: Temperature: 5–50 °C
Other:
Feedstock and product details
Feedstock: from water-based industrial fluids, coolants Product: seperated / cleaned fractions

Alfa Laval is a leading global provider of first-rate products in the areas of heat transfer, separation and fluid handling. With these as its base, Alfa Laval aims to help enhance the productivity and competitiveness of its customers in various industries throughout the world. We define their challenges and deliver sustainable products and solutions that meet their requirements – mainly in energy, the environment, food and the marine industry.

Alfie is a simple to use separator: Turnkey, portable, small footprint, centrifugal disc stack separators that remove contaminating oil, grease and solid particles from water-based industrial fluids such as coolants and wash liquids.

Ecofast

Centrifugation provider
General information
Company: Ecofast Italia S.r.l. 21-04-27 Tech4Biowaste rect-p.png
Country: Italy
Contact:
Webpage: www.ecofast.eu
Technology and process details
Technology name: DeHydra SC1B Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: Capacity: 300 kg/h l·h-1
Processable volume: L Relative centrifugal force: 930 rpm g
Rotor type: Pump rotor Temperature: °C
Other:
Feedstock and product details
Feedstock: Food waste Product: De-watered food waste

Ecofast Italia is an innovative SME that designs and manufactures equipment to compact food waste in professional catering and catering. The use of our machines makes the kitchen more hygienic and clean and helps to improve the safety of the working environment. Less waste to be disposed of, less waste in landfills, less greenhouse gases produced for their collection.

From the beginning, the company’s activity has been characterized by a more marked technical connotation, carrying out, first in Italy, not only important tests in the use of food waste disposes, but an innovative research and development activity to the invention of new patents for new products/technologies in order to enhance a more sustainable and economic management of food waste. Ecofast Italia S.r.l. – Environmental Technology was established in Milan on November 23th 1998, at first to import and distribute food waste disposers for domestic and professional users, in Europe.

The DEHYDRA SC1 can be placed in the washing area or in cleaning areas of canteens and/or restaurants where it is required to dispose of up to 150 kgs per hour of food waste. Our compact food waste reduction machine is a stainless steel standalone de-watering solution, made up of a hydro extractor, and a centrifugal press which separates the liquid from the solid component. The DeHydra dewater apparatus is the only self-cleaning de-watering system that can be fitted with wastewater re-circulation.

Flottweg

Centrifugation provider
General information
Company: Flottweg SE 21-04-27 Tech4Biowaste rect-p.png
Country: Germany
Contact:
Webpage: https://www.flottweg.com/
Technology and process details
Technology name: SEDICANTERS® S6E-3 Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: Capacity: 25 - 40 Mt/h l·h-1
Processable volume: Up to 50 m3/h L Relative centrifugal force: 3650 rpm, 5000 x g g
Rotor type: Flottweg Simp Drive® Temperature: Up to 100 °C
Other:
Feedstock and product details
Feedstock: Biomass, yeast suspensions, protein suspensions, fermentation broths etc. Product: Clarification, dewatering, thickening of sludge, separation of three-phase mixtures, classification of solids, sorting of solids by density

Flottweg has their headquarters in Vilsbiburg, Germany and has been manufacturing centrifuges, belt presses, and processing systems for mechanical solid-liquid separation for more than 60 years. This technology encompasses core functions in many industrial sectors, i.e. clarifying liquids, separating liquid suspensions and concentrating and dewatering solids. Our company has grown to more than 750 employees and we achieve sales of 152 Million Euro, with an export rate of more than 85 %.

Flottweg Sedicanters® are used for the continuous separation of fine solids from liquids with the solids forming a soft to flowing sediment. Flottweg Sedicanters® are preferably used in cases where the solids are too fine to be effectively processed in a decanter and the sediment cannot be easily discharged from the decanter due to its soft consistency. Flottweg’s range of Sedicanter® sizes includes machines with capacities up to 50 m3 /h (220 gallons per minute).

Imperial Machine Company Ltd. (IMC)

Centrifugation provider
General information
Company: Imperial Machine Company Ltd. (IMC) 21-04-27 Tech4Biowaste rect-p.png
Country: United Kingdom
Contact:
Webpage: https://www.lincat.co.uk/index.php?p=brands/imc
Technology and process details
Technology name: Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: Capacity: 700 kg/h l·h-1
Processable volume: L Relative centrifugal force: g
Rotor type: Temperature: °C
Other:
Feedstock and product details
Feedstock: Soft waste (plate waste, vegetable peelings, meet and fish scraps), medium waste (small pork and chicken bones, vegetables and fruit), tough waste (all red meat bones, cauliflower stalks and fish skins). Product: Dewatered and macerated food waste.

Imperial Machine Company (IMC) has their headquarters in Lincoln, UK and has been engineering catering solutions for more than 110 years. We have designed, installed and supported catering products for foodservice operations for generations; a fact we at IMC are immensely proud of.

Food waste typically represents around 40% of total commercial catering waste. It is difficult and costly to process and dispose of this efficiently. Of this 40%, approximately 77% is liquid. WasteStation grinds the food waste into fine particles, which are fed directly into a built-in dewatering system, or for where space in the kitchen is limited, a remote dewatering system. Through centrifugal action, excess liquid is forced out. The resulting solid fraction of the food waste is collected in small, easily managed, lidded bins, ready for onward processing.

Rendisk

Centrifugation provider
General information
Company: Rendisk B.V. 21-04-27 Tech4Biowaste rect-p.png
Country: The Netherlands
Contact:
Webpage: https://www.rendisk.com/
Technology and process details
Technology name: Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: Capacity: 450 kg/h l·h-1
Processable volume: L Relative centrifugal force: g
Rotor type: Temperature: °C
Other:
Feedstock and product details
Feedstock: Food waste Product: De-watered food waste

Founded in Ruurlo, the Netherlands in 1973, Rendisk has grown to become a leader with the brand Rendisk in dishwashing logistics and food waste solutions for professional kitchens in locations around the world. We support kitchen teams with smart logistic solutions for dishwashing and groundbreaking solutions for processing your kitchen waste. All our efforts are focused on making work in the kitchen easier, more efficient and more sustainable. But always with care for the local and world environment most in mind.

The Rendisk Solus Eco is our most compact solution for food waste treatment and can rapidly deal with all kinds of organic food waste. Unique to the Solus Eco is that it’s a standalone unit. Thanks to its innovative technique it has an extremely small footprint and therefore fits in any kitchen or garbage room, but still can reduce your food waste massively.

The Rendisk Solus Eco is a clean and easy to use waste solution for restaurants and business restaurants, universities, hospitals, hotels, maritime areas and locations like holiday and entertainment parks. It’s the perfect food waste solution for anyone who believes in sustainability and efficiency. You simply load the food waste into the hopper. It is then ground and dehydrated using a special centrifugal technique. It’s due to this technique that the Solus Eco can reduce your food waste by up to 80%, lowering your removal cost dramatically. The Rendisk water management system reduces the water consumption considerably comparing with similar systems. Our smart technology reuses the water in the system allowing for a significant reduction in washed water.

Tidy Planet

Centrifugation provider
General information
Company: Tidy Planet Limited TidyPlanetLogo.jpg
Country: United Kingdom
Contact: Huw Crampton
Webpage: https://tidyplanet.co.uk/
Technology and process details
Technology name: DeHydra Super Compact Technology category: Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL: 9 Capacity: 700 kg/h l·h-1
Processable volume: 700 - 1400 L/h L Relative centrifugal force: g
Rotor type: Screw system encapsulated in a stainless steel mesh with 1.5 mm perforations Temperature: 5 - 60 °C
Other:
Feedstock and product details
Feedstock: Food waste Product: Ground and de-watered food waste

Tidy Planet present the widest range of on-site food waste recycling products on the market, tested and manufactured to the highest quality standards here in the UK – tackling on-site, commercial food waste volumes ranging from 20kg to 20 tonnes of food waste per day.

The Dehydra Food Waste Dewatering system has the capacity to reduce food waste volume by up to 80% and weight by up to 50%, through a process of shredding and then using a centrifuge to separate the liquid wastes, such as sauces, soups and juices. The greatly reduced volume of finely shredded particles of food are captured and deposited into a bin in the footprint of the unit and the weighty liquid effluent disposed to sewer.

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Patents

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References

  1. ↑ Changzhi Bai, Hangil Park, Liguang Wang, 2021-08-15: Measurement of solids concentration in aqueous slurries for monitoring the solids recovery in solid bowl centrifugation. Minerals Engineering, Vol. 170, 107068. doi: https://doi.org/10.1016/j.mineng.2021.107068
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