Dolphin Centrifuge

Biodiesel Centrifuge | Separating Biodiesel from Glycerin

biodiesel-centrifuge

Table Of Contents

What is Biodiesel?

Biodiesel is an organic, renewable alternative to conventional diesel fuel. It is environmentally friendly due to lower emissions and is usable in current engines designed to operate on diesel fuel.

Biodiesel is not to be confused with black diesel which is also an alternative fuel but is made from used oils.

How is Biodiesel Produced?

The transesterification process converts organic fats and oils into biodiesel. In other words, transesterification is the process of converting fats into biodiesel and glycerin. Methanol and lye are the catalysts in the process. The lipids are animal fat or used vegetable oil.

Large-scale production of biodiesel utilizes Alfa Laval biodiesel centrifuges for high volume, continuous processing of feedstock, and separation of biodiesel from glycerin.

Biodiesel Centrifuge

Alfa Laval MOPX-207 Biodiesel Centrifuge
Alfa Laval MOPX-207 Biodiesel Centrifuge

A biodiesel centrifuge uses a high g-force of 8,000 Gs to separate biodiesel from glycerin. The centrifuge bowl rotates at 7,000 RPM. The centrifugal force spins out the denser glycerin to discharge out the heavy phase outlet. The lighter biodiesel discharges through the biodiesel chamber outlet.

A small 'self-cleaning' centrifuge is able to separate 10 GPM of biodiesel and 5 GPM of hot WVO.

Advantages

The following are key advantages of centrifuges in biodiesel production.


If you have simple, routine questions: We have condensed our 40+ years of disc-stack centrifuge experience into 101 Frequently Asked Questions about Disc Stack Centrifuges!


Centrifuge Applications in Biodiesel Processing

The commercial biodiesel production process uses industrial centrifuges in most of the production steps. The list below explains each step with the corresponding centrifuge application.

WVO Purification

The WVO (Waste Vegetable Oil) feedstock contains water and food particles that need separation prior to the biodiesel conversion process. The three-phase disc stack centrifuge separates all free-water and sediment down to the 1-micron level from WVO. This separation is a continuous (flow-through) process.

See our case study on the use of Alfa Laval centrifugal separators for large-scale WVO purification.

Biodiesel Glycerol Separation

Post reaction is essential to separate the two immiscible liquid phases (biodiesel and glycerol) to get pure biodiesel. It is critical to remove all traces of glycerol and any sediment to reduce the load on the next process step.

Industrial centrifuges are a proven way to separate the two liquids at this stage. Alfa Laval industrial centrifuges (disc-stack type) generate a high centrifugal force on the fluid. This force separates the glycerol from the biodiesel to produce ASTM-grade biodiesel. Especially in cases where virgin vegetable oils are the feedstock.

Biodiesel Wash Water Separation

Biodiesel produced using WVO or animal fat needs a further step to remove any remaining impurities. A simple water wash polishes the biodiesel to the ASTM purity level.

An industrial centrifuge is the best fit for the separation of wash water from biodiesel. High centrifugal force in the disc stack centrifuge separates the water from biodiesel. This separation is, again, a continuous, efficient process.

Biodiesel Final Polishing

Polishing the biodiesel removes tiny particulate matter from the finished biodiesel. In the case of water wash, trace amounts of water may still be present in the biodiesel. The Alfa Laval centrifuge removes the water from the biodiesel at this polishing stage.

Glycerin Clarification

Distilling separated glycerol recovers the methanol and produces glycerin. Pure glycerin has good resale value and is in demand in the food and cosmetics industries.

Clarification of glycerin to remove small impurities makes it usable. A disc stack centrifuge has the required g-force to remove the finest trace particles from glycerin.

The advantages of using industrial centrifuges (listed above) are applicable for glycerin purification as well.

Biodiesel Centrifuge Design

Biodiesel production requires the use of methanol. This requirement, in turn, needs unique manufacturing specifications. Biodiesel centrifuge systems manufactured by Dolphin Centrifuge have the following features. We refer to these features as the ‘Biodiesel Kit.’

FAQ

Does a biodiesel centrifuge need to be rated for hazardous areas? Why?

A biodiesel centrifuge needs to be rated for operating in hazardous areas. This rating is essential because methanol (flammable liquid) is often present in biodiesel production facilities. It is a requirement to use hazardous area certified equipment in area with flammable fluids present.

What is the smallest biodiesel centrifuge?

The smallest biodiesel centrifuge is an Alfa Laval MAB 103 that can process approximately 1 gallon per minute of a biodiesel glycerol mix.

Do biodiesel centrifuge need special modifications?

Biodiesel centrifuges are standard centrifuges that are specially modified to process biodiesel. Some of the modifications include the use of special elastomers (instead of nitrile), electrical components suitable for hazardous areas, protective coating for parts affected by biodiesel, etc.

Why do I need a centrifuge when biodiesel easily separates from glycerin?

Biodiesel and glycerin separate quickly under gravity. However, the complete separation to produce 100% pure biodiesel can take a long period. A biodiesel centrifuge speeds up the separation by exerting up to 10,000 times the force for gravity to quickly produce 100% pure biodiesel without the need for decanting.

What is the largest biodiesel centrifuge?

The largest biodiesel centrifuge processes over 200 gallons per minute of a biodiesel glycerin mix. This centrifuge is an Alfa Laval, 3-phase, disc stack type centrifuge.

Does a biodiesel centrifuge have other applications in biodiesel production?

A biodiesel centrifuge of the self-cleaning type is useful to separate water and sludge from WVO. The same centrifuge is also suitable to separate wash water from biodiesel in the wash process. Glycerin purification is another application for biodiesel centrifuges.

Can a biodiesel centrifuge produce ASTM grade biodiesel?

A properly set up and tuned biodiesel centrifuge can produce biodiesel to meet or exceed ASTM biodiesel standards.

Is a biodiesel centrifuge expensive to operate?

The only operation-related expense of a biodiesel centrifuge is the cost of electricity. As an example, the cost to produce 1,200 gallons of biodiesel with a centrifuge is less than $1.00 based on electricity cost.

Specifications

Centrifuge TypeAlfa Laval Disc Stack Centrifuge with Biodiesel Kit
ModelBDB 104BDPX 207BDB 209
Sludge HandlingManual CleanSelf-CleaningManual Clean
Biodiesel Kit FeaturesCompatible Elastomer, Corrosion Resistant Top-coat, Friction Clutch Replacement, Motor Suitable for Hazardous Applications
Capacity
Titrated WVO Stock3 GPM10 GPM35 GPM
Glycerin Separation6 GPM18 GPM60 GPM
Wash-Water3 GPM10 GPM35 GPM
Glycerin Clarification5 GPMNot Suitable40 GPM
Motor2 HP10 HP15 HP
Bowl Speed7,500 RPM6,400 RPM6,700 RPM
Sludge Space0.325 Gal1.3 Gal2.0 Gal
Alfa Laval MAB205 Teflon Coated Biodiesel Centrifuge
Alfa Laval MAB205 Biodiesel Centrifuge

Alfa Laval MAB205

Technical Specifications
Capacity 15 GPM on Biodiesel Glycerin
Motor Power 5 HP
Voltages 230 / 460 3-Phase
Size 4' x 5'
Weight 2,000 Lbs
Options Teflon Coated Covers
Alfa-Laval-MAB206-Biodiesel
Alfa Laval MAB206 Biodiesel Centrifuge

Alfa Laval MAB206 

Technical Specifications
Capacity 25 GPM on Biodiesel Glycerin
Motor Power 7.5 HP
Voltages 230 / 460 3-Phase
Size 4' x 6'
Weight 2,500 Lbs
Options Teflon Coated Covers
Alfa-Laval-MAB207-Biodiesel
Alfa Laval MAB207 Biodiesel Centrifuge

Alfa Laval MAB207 

Technical Specifications
Capacity 50 GPM on Biodiesel Wash Water
Motor Power 15 HP
Voltages 230 / 460 3-Phase
Size 5' x 5'
Weight 2,800 Lbs
Options VITON O-Rings

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