Biodiesel Production from Algae Oil
Biodiesel Production from Algae Oil
The major problem associated with the use of pure vegetable oils as well as oil from algea as fuels for diesel engines is caused by high fuel viscosity (Viscosity – from Physics Hypertextbook) in compression ignition. Algal oil, as well as vegetable oils, are all highly viscous, with viscosities ranging 10–20 times those of no. 2 Diesel fuel. Amongst vegetable oils in the context of viscosity, castor oil is in a class by itself, with a viscosity more than 100 times that of no. 2 Diesel fuel (MSDS of No.2 Diesel Fuel – PetroCard). Due to their high viscosity and low volatility, they do not burn completely and form deposits in the fuel injector of diesel engines. Furthermore, acrolein (a highly toxic substance) ( Acrolein – from EPA) is formed through thermal decomposition of glycerol (Glycerol – from Info Please).
Dilution, micro-emulsification (Emulsions & Emulsification – from Wikipedia), pyrolysis ( Pyrolysis Definition from AFR) and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Amongst the four techniques, chemical conversion of the oil to its corresponding fatty ester is the most promising solution to the high viscosity problem. This process - chemical conversion of the oil to its corresponding fatty ester, and thus biodiesel - is called transesterification.
Transesterification of Algal Oil into Biodiesel
Transesterification of algal oil is normally done with ethanol and sodium ethanolate serving as the catalyst. Sodium ethanolate can be produced by reacting ethanol with sodium. Thus, with sodium ethanolate as the catalyst, ethanol is reacted with the algal oil ( the triglyceride) to produce bio-diesel & glycerol. The end products of this reaction are hence biodiesel, sodium ethanolate and glycerol. This end-mixture is separated as follows: Ether and salt water are added to the mixture and mixed well. After sometime, the entire mixture would have separated into two layers, with the bottom layer containing a mixture of ether and biodiesel. This layer is separated.
Biodiesel is in turn separated from ether by a vaporizer under a high vacuum. As the ether vaporizes first, the biodiesel will remain. The biodiesel from algae is now ready for use!
Centrifuges
A centrifuge is a useful device for both biolipid extraction from algae and chemical separation in biodiesel.
Centrifuge Applications
There are several steps in the biodiesel production process where centrifugation is useful.
· Feedstock preparation - In this case, algae must first be separated from its medium, then the oil extracted from the algae.
· Separation of transesterification products – Biodiesel and glycerine must be separated, and any leftover reactants removed.
· Water wash – Biodiesel can be washed of soap and glycerine using a centrifuge.
· Magnasol solids removal - As an alternative to water washing, it may be possible to wash the biodiesel in Magnasol.
The parameters to be considered while evaluating the ideal algae processor are:
· Capacity/throughput of the system
· Speed/density
links and news items on Bio Diesel on the right side
The major problem associated with the use of pure vegetable oils as well as oil from algea as fuels for diesel engines is caused by high fuel viscosity (Viscosity – from Physics Hypertextbook) in compression ignition. Algal oil, as well as vegetable oils, are all highly viscous, with viscosities ranging 10–20 times those of no. 2 Diesel fuel. Amongst vegetable oils in the context of viscosity, castor oil is in a class by itself, with a viscosity more than 100 times that of no. 2 Diesel fuel (MSDS of No.2 Diesel Fuel – PetroCard). Due to their high viscosity and low volatility, they do not burn completely and form deposits in the fuel injector of diesel engines. Furthermore, acrolein (a highly toxic substance) ( Acrolein – from EPA) is formed through thermal decomposition of glycerol (Glycerol – from Info Please).
Dilution, micro-emulsification (Emulsions & Emulsification – from Wikipedia), pyrolysis ( Pyrolysis Definition from AFR) and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Amongst the four techniques, chemical conversion of the oil to its corresponding fatty ester is the most promising solution to the high viscosity problem. This process - chemical conversion of the oil to its corresponding fatty ester, and thus biodiesel - is called transesterification.
Transesterification of Algal Oil into Biodiesel
Transesterification of algal oil is normally done with ethanol and sodium ethanolate serving as the catalyst. Sodium ethanolate can be produced by reacting ethanol with sodium. Thus, with sodium ethanolate as the catalyst, ethanol is reacted with the algal oil ( the triglyceride) to produce bio-diesel & glycerol. The end products of this reaction are hence biodiesel, sodium ethanolate and glycerol. This end-mixture is separated as follows: Ether and salt water are added to the mixture and mixed well. After sometime, the entire mixture would have separated into two layers, with the bottom layer containing a mixture of ether and biodiesel. This layer is separated.
Biodiesel is in turn separated from ether by a vaporizer under a high vacuum. As the ether vaporizes first, the biodiesel will remain. The biodiesel from algae is now ready for use!
Centrifuges
A centrifuge is a useful device for both biolipid extraction from algae and chemical separation in biodiesel.
Centrifuge Applications
There are several steps in the biodiesel production process where centrifugation is useful.
· Feedstock preparation - In this case, algae must first be separated from its medium, then the oil extracted from the algae.
· Separation of transesterification products – Biodiesel and glycerine must be separated, and any leftover reactants removed.
· Water wash – Biodiesel can be washed of soap and glycerine using a centrifuge.
· Magnasol solids removal - As an alternative to water washing, it may be possible to wash the biodiesel in Magnasol.
The parameters to be considered while evaluating the ideal algae processor are:
· Capacity/throughput of the system
· Speed/density
links and news items on Bio Diesel on the right side
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