Comparison of Oilseed Extraction Methods; Mechanical Pressing, Supercritical Fluid Extraction, and Solvent Extraction
Mechanical pressing
The oil produced is cloudy and contains a high proportion of water and metals, with oil yields of 75-85% (Liauw et al., 2008; Ofori-Boateng et al., 2012). Oil quality can also be lowered by a loss of heat to the surrounding environment due to friction (Ofori-Boateng et al., 2012).
Extraction is done using a screw press or an oil expeller and requires the use of technology such as an acidic or enzymatic material to weaken cell walls prior to extraction (Mercer and Armenta, 2011).
This method of extraction is the most commonly used and has been used for centuries, originating in Greece for the purpose of extracting olive oil (Ofori-Boateng et al., 2012).
This method has a very low investment cost yet a high operational cost for the replacement of machinery (Ofori-Boateng et al., 2012).
Photo Source: http://making-biodiesel-books.com/about-algae/algae-oil-extraction/
Supercritical fluid extraction
This method extracts between 36-43% of oil content (Bulley et al., 1984). Additional purification using gasses such as CO2 removes any impurities and gumming materials, yielding a high concentration of raw material (Bulley et al., 1984).
Material for extraction is placed in an apparatus such as the Soxhlet with the solvent added in small amounts (Hedrick et al., 1992; Reverchon, 1997). CO2 is often used as a solvent material as it is completely non-toxic and does not require intense pressure or temperature conditions for extraction (Reverchon, 1997).
This type of extraction requires a large amount of power for processing and time, up to 72 hours (Hedrick et al.,1992). Additionally, it is non-toxic as there is no requirement of organic solvents for extraction, which leaves harmful residues. (Mercer and Armenta, 2011). In terms of cost, this method is relatively cheap as it costs less to obtain the gaseous solvent (Bulley et al., 1984).
Solvent Extraction
Oil contains lower solid components however; the oil produced is not as pure as that of supercritical fluid extraction. This method extracts 99% of oil content (Liauw et al., 2008; Ofori-Boateng et al., 2012; Mercer and Armenta, 2011).
Extraction requires the use of an organic solvent, with the most common choices being n-hexane or ethanol (Johnson and Lusas, 1983). The solvent is mixed with the seed and then extracted using a centrifuge (Ofori-Boateng et al., 2012).
In the past decade the cost of obtaining the n-hexane has increased 6-8 fold making this process expensive along with the operational costs (Johnson and Lusas, 1983).
The oil produced is cloudy and contains a high proportion of water and metals, with oil yields of 75-85% (Liauw et al., 2008; Ofori-Boateng et al., 2012). Oil quality can also be lowered by a loss of heat to the surrounding environment due to friction (Ofori-Boateng et al., 2012).
Extraction is done using a screw press or an oil expeller and requires the use of technology such as an acidic or enzymatic material to weaken cell walls prior to extraction (Mercer and Armenta, 2011).
This method of extraction is the most commonly used and has been used for centuries, originating in Greece for the purpose of extracting olive oil (Ofori-Boateng et al., 2012).
This method has a very low investment cost yet a high operational cost for the replacement of machinery (Ofori-Boateng et al., 2012).
Photo Source: http://making-biodiesel-books.com/about-algae/algae-oil-extraction/
Supercritical fluid extraction
This method extracts between 36-43% of oil content (Bulley et al., 1984). Additional purification using gasses such as CO2 removes any impurities and gumming materials, yielding a high concentration of raw material (Bulley et al., 1984).
Material for extraction is placed in an apparatus such as the Soxhlet with the solvent added in small amounts (Hedrick et al., 1992; Reverchon, 1997). CO2 is often used as a solvent material as it is completely non-toxic and does not require intense pressure or temperature conditions for extraction (Reverchon, 1997).
This type of extraction requires a large amount of power for processing and time, up to 72 hours (Hedrick et al.,1992). Additionally, it is non-toxic as there is no requirement of organic solvents for extraction, which leaves harmful residues. (Mercer and Armenta, 2011). In terms of cost, this method is relatively cheap as it costs less to obtain the gaseous solvent (Bulley et al., 1984).
Solvent Extraction
Oil contains lower solid components however; the oil produced is not as pure as that of supercritical fluid extraction. This method extracts 99% of oil content (Liauw et al., 2008; Ofori-Boateng et al., 2012; Mercer and Armenta, 2011).
Extraction requires the use of an organic solvent, with the most common choices being n-hexane or ethanol (Johnson and Lusas, 1983). The solvent is mixed with the seed and then extracted using a centrifuge (Ofori-Boateng et al., 2012).
In the past decade the cost of obtaining the n-hexane has increased 6-8 fold making this process expensive along with the operational costs (Johnson and Lusas, 1983).
It should be noted that oilseed extraction is sensitive to temperature as high manufacturing temperatures can degrade oil quality (Ofori-Boateng et al., 2012). High temperatures during production can increase saponification, peroxide content and pH making the oil more acidic and in addition can decrease iodine content (Liauw et al., 2008). Mechanical extraction with a solvent is more efficient than simply using mechanical extraction, as the action of applying the solvent after pressing allows for a higher quantity of oil to be extracted (Rosenthal et al., 1996).
Figure 1: Breakdown of Steps in Oilseed Extraction Using Mechanical Extraction with Solvent (Rosenthal et al., 1996; Lamsal et al., 2006; Ofori-Boateng et al., 2012
Neem Oil Source and Manufacturing
The insecticide would be manufactured at the Ultra-Bio Logics plant however, it is unclear as to whether their previous manufacturing processes required a Neem oil extract or Neem oil that was obtained directly from trees grown at the facility. Assuming the trees were grown on site, it would require a minimum of 15 years for the trees to reach productivity at which point the seeds can be harvested for oil production (Schmutterer, 1990). Seed propagation can occur as early as 9 to 12 months in the nursery and can then be transferred to the field through transplanting (Koul et al., 1990). The climate in Canada would be appropriate for growth of the trees, as they possess the capacity to grow at low temperatures between 50 m to 100 m in altitude (Koul et al., 1990).
The insecticide would be manufactured at the Ultra-Bio Logics plant however, it is unclear as to whether their previous manufacturing processes required a Neem oil extract or Neem oil that was obtained directly from trees grown at the facility. Assuming the trees were grown on site, it would require a minimum of 15 years for the trees to reach productivity at which point the seeds can be harvested for oil production (Schmutterer, 1990). Seed propagation can occur as early as 9 to 12 months in the nursery and can then be transferred to the field through transplanting (Koul et al., 1990). The climate in Canada would be appropriate for growth of the trees, as they possess the capacity to grow at low temperatures between 50 m to 100 m in altitude (Koul et al., 1990).