Advancement in neem oil extraction process

This paper describes a process of preparation of neem oil water emulsion & coating of urea in fertilizer plants, at site of urea production. The neem tree found in Asia and basically Indian sub continent. The basic part for neem oil used is seed of the neem known as kernels .Different method are available to obtain neem oil including one new method Supercritical method for extraction of neem oil from kernels.Now a days the main demand of neem oil in fertilizers Industries for coating of Urea and other fertilizers. “Government of India has done away with the cap on neem- coated urea and now it can be produced 100%. It is a win-win situation for both industry and farmers. It has been noted that farmer’s income would increase with the help of neem-coated urea as productivity would increase with less usage of urea.”Consequently the demand of Neem oil drastically increasing. In this paper some description of oil preparation method. Using carbon dioxide: methanol for supercritical fluid extraction is the maximum yield eco friendly process but slightly economical.

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Advancement in Neem oil Extraction Process
ARTICLE · JANUARY 2016
1 AUTHOR:
Prem Baboo
National Fertilizers Ltd.,India
28 PUBLICATIONS 0 CITATIONS
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Available from: Prem Baboo
Retrieved on: 31 January 2016

2. ADVANCEMENT
IN
NEEM OIL EXTRACTION PROCESS





Author

Prem Baboo
Sr. Manager (Prod)
[email protected]
Mob. [phone]
National fertilizers Ltd.Vijaipur,-473111, India
Sr. advisor & Expert, www.ureaknowhow.com
Fellow of Institution of Engineers (India)

3. ABSTRACT
Now a days the main demand of neem oil in fertilizers Industries for coating of Urea and other fertilizers.
“Government of India has done away with the cap on neem- coated urea and now it can be produced 100%. It is a win-win
situation for both industry and farmers. It has been noted that farmer’s income would increase with the help of neem-coated
urea as productivity would increase with less usage of urea.”Consequently the demand of Neem oil drastically increasing. In
this paper some description of oil preparation method. Using carbon dioxide: methanol for supercritical fluid
extraction is the maximum yield eco friendly process but slightly economical.
KEYWORD
Neem oil, Azadirachtin (C
35H
44O
16), n-hexane, Distillation, Cold press, solvent Extraction, Neem coated urea, mechanical
pressing, crushing, Evaporation. Supercritical fluid extraction, Azadirachta indica.
INTRODUCTION
This paper describes a process of preparation of neem oil water emulsion & coating of urea in fertilizer plants, at
site of urea production. The neem tree found in Asia and basically Indian sub continent. The basic part for neem
oil used is seed of the neem known as kernels .Different method are available to obtain neem oil including one
new method Supercritical method for extraction of neem oil from kernels.
Neem oil extraction is done by mainly following four different types of technologies are available,
1. Mechanical Pressing,
2. Steam Pressure Extraction,
3. Solvent Extraction, and
4. Super Critical Extraction
Basically in India mechanical process is mainly used. The Kernels contain about 50-65 % oil. There are merits
of mechanical process. The supercritical process is now being popular because maximum yields and eco
friendly.
STEPS OF THE PROCESS

Fig. No. -1 (Process Flow diagram)

4. Collection of the Kernels
The kernels are collected from gardens, the neem trees are planted for this purpose the generally the flouring of
the ground neat & clean so that the kernels easily can be collected without dirt and sand. The commercialisation
of neem products requires an effective and reliable collection system for neem kernels, it turns out that reliable
collection and preparation of neem kernels of good quality for a reasonable price is one of highest hurdles in
setting up neem processing in India. On the one hand, in participatory training communities have to be
persuaded to collect neem seeds during the one or two local harvesting seasons and to accept neem as an
additional cash crop; on the other hand there has to be a commitment on the part of the entrepreneurs to buy a
certain amount of the collected seeds frequently, even if they cannot process them all due to marketing
problems.
1. Mechanical Press Method:
This method is one of methods of processing oil. Seeds are placed in a tub or container and a form of press or
screw is used to squeeze the seeds until the oil is pressed out. Mechanical extraction of Neem seeds performs
using hydraulic pressing equipment .Untreated seed particles to be pressed with various pressures to determine
the optimum pressure. Pressure was started at 138 Bar as the oil started to flow out of the seedbed, and stopped
at 412 bars since the oil yield relatively constant at the pressure above 413 bars. Mechanical extraction was
performed for 25 minutes when the oil has stopped flowing out. Oil yield measurement was conducted using
mass balance .Neem seeds kernels are placed in to a vessel and either a screw or some of form of press is used
to squeeze the kernels under pressure until the oil is pressed out and collected. The neem oil is obtained by
pressing it mechanically and collected in a drum. Thus filtration is done to remove the various unwanted
particles left in the extracted oil in order to obtain pure neem oil. The Pressure Vs percentage yield as shown in
the Graph No.1.

Graph No. 1
0
5
10
15
20
25
30
35
2000 3000 4000 5000 6000
YIELD IN PERCENTAGE

PRESSURE IN PSI
Pressure Vs Yield

5. Fig. No. 2 (Crusher)
2. Steam pressure extraction,
This method uses steam and high pressure to extract the oil. The kernels are heated with steam to increase the
oil flow then squeeze under high pressure. Most of the oil is extracted from the kernels. This process makes the
extraction process easier. The seeds get swollen by steaming thus the oil in squeezing becomes easy. The
process of steaming is accompanied by increasing of pressure in the boiler which drives the oil out from the seed
without any pressing. In some industries, the left seed's kernels after the steam boiling is pressed to further
extraction of oil up to 98% leaving just the outer layer of the seeds. The same filtering process is followed as
done in the mechanical pressing method. The same filtering process is followed as done in the mechanical
pressing method.
3. Extraction Method
Before the extraction the seeds gets well cleaned manually all the leaves & dirt to be removed with blower air
And heating of the seeds starts with hot air the temperature of the seeds raise up to 55-60
0
C so that the all the
moisture can be removed. After the completion of the seed preparation steps, extraction of oil from grinded
neem seeds carries. Extraction involved the use of: soxhlet extractor (coupled with heating mantle) and
extraction solvents .The suitable temperature and time may be selected for maximum gains, some practical’s
results are obtained in Graph No. 2 & 3 as following.

Graph No. 2

6. The solvent uses Ethanol & Hexane with different time gap, The yield can be done at 60% Ethanol &40 %
Hexane, 60% hexane & 40 ethanol,50% Ethanol & 50 Hexane and uses 100% ethanol and 100 n hexane etc.
practical can be done, when suitable yields reaches that is the final ratio for maximum yields as shown in the
graph No.-3

Graph No.3
It has been observed when hexane and ethanol were used separately (as solvent), showed that an increase in
temperature generally favours an increase in oil yield. This phenomenon is due to the fact that oils are generally
more soluble at elevated temperatures as shown in the graph No.-2
At higher temperatures, the viscosity of the solvent is reduced while the diffusivity, as well as evaporation rate
is increased. This increases the contact time between the solvent and the oil bearing material. The net effect of
this is that more oil is dissolved in the solvent per time, thereby increasing oil yield.
At same temperature, the results showed that hexane is a better extraction liquid, for higher yields were
obtained. Even when ethanol is used at higher temperatures (temperatures above boiling point of hexane), oil
yields obtained were still very low (Figure 1). And in each case, the optimum extraction temperature is 55-60
0
C. The result shows that pure ethanol cannot be a good substitute for hexane, as extraction liquid. Further
investigated were carried out to see whether combination of ethanol and hexane would produce higher oil yield
than pure hexane at the optimum temperature of 55-60
0
C
Properties of Neem oil Extracted
Sr. No. Solvent Acid value Sap. value Specific
Gravity
P
H

1 Ethanol 19.35 198.5 0.87 5.7
2 Hexane 20.05 201.0 0.90 6.1
3 50/50 %
Hexane/Ethanol
18.79 198.7 0.91 5.9
4 60/40 Hexane/Ethanol 12.9 200.0 0.92 5.8
5 40/60 Hexane/Ethanol 17.11 198.4 0.90 5.8
Table No.1
It has been observed the ability of the ethanol-hexane mixture to perform better than ethanol or hexane is due to
the fact that the mixture is able to reduce the flammability usually associated with pure hexane solvent. The

7. effect of being able to operate at a temperature higher than the boiling point temperature is due to an increased
rate of: diffusion, evaporation and cooling. It has been also observed the quality of the neem oil decreased as the
temperature increased. The oil quality is also affected by temperature, Oxidation Hydrolysis and another
impurity present in the oil.

Fig. No. 3 (Process Flow diagram of Neem oil Extraction from Ethanol)

8. Fig.No.-4 (Pilot Neem oil Extraction Plant)

4. Super Critical Extraction
This process utilises carbon dioxide at critical temperatures above (31.1
0
C) and pressures (above 72.9 atm) to
extract the active ingredients of the neem leaf without the usual high temperatures or harmful chemicals. This
result in a far more concentrated extract, which resembles the herb more closely. Our neem products are
extracted shortly after harvesting to capture all the healing phytochemicals with superior potency and purity.
PROPERTIES OF CARBON DI OXIDE AT CRITICAL CONDITION
Property Value Unit
Medium : carbon dioxide
state of aggregation Super critical fluid
Pressure : 74 [ bar ]
Temperature : 332.5 [ Celsius ]
Density : 66.13955 [ kg / m
3
]
Specific Enthalpy : 791.1885 [ kJ / kg ]
Specific Entropy : 2.584005 [ kJ / kg K ]
Specific isobar heat capacity, Cp 1.1381 [ kJ / kg K ]
Table No.2

9. The Carbon di Oxide properties tabulated in Table No.2

Fig. No. 5 (Critical Properties of CO2)
This extraction process uses only carbon dioxide as a solvent, which once the pressure is let off evaporates
completely from the extract, leaving it totally pure and free of any solvent residues. The 'Super Critical Point' is
the exact temperature and pressure at which a gas becomes a liquid. In the case of carbon dioxide, this is a
relatively low 31 deg. Centigrade. The system must contain a pump for the CO2 as shown in the figure 6, a
pressure cell to contain the sample, a means of maintaining pressure in the system and a collecting vessel. The
liquid is pumped to a heating zone, where it is heated to supercritical conditions. It then passes into the
extraction vessel, where it rapidly diffuses into the solid matrix and dissolves the neem oil. The Neem oil is
swept from the extraction cell into a separator at lower pressure, and the neem oil settles out. The CO2 can then
be cooled, recompressed and recycled, or discharged to working tank; this is the cycle of carbon dioxide.
The system must contain a pump for the liquid Carbon Dioxide, a pressure cell to contain the sample, a means
of maintaining pressure in the system and a collecting vessel. The liquid carbon Dioxide is pumped to a heating
zone, where it is heated to supercritical conditions. It then passes into the extraction vessel, where it rapidly
diffuses into the solid matrix and dissolves the neem oil. The Neem oil is swept from the extraction cell into a
separator at lower pressure, and the neem oil settles out. The CO2 can then be cooled, recompressed and
recycled, or discharged to working tank; this is the cycle of carbon dioxide.

Carbon dioxide is usually pumped as a liquid, usually below 5°C and a pressure of about 50 bars. The solvent is
pumped as a liquid as it is then almost incompressible. As a supercritical fluid, much of the pump stroke will be
"used up" in compressing the fluid, rather than pumping it. For small-scale extractions (up to a few
grams/minute), reciprocating CO2 pumps or centrifugal pump are often used. For larger scale extractions,
diaphragm pumps are most common for small scale plant. The pump heads will usually require cooling, and the
CO2 will also be cooled before entering the pump.

Pressure vessels can range from simple tubing to more sophisticated purpose built vessels with quick release
fittings. The pressure requirement is at least 74 bars; the vessel must be equipped with a means of pressure
safety valve. It can be placed outside on top of the vessel Care must be taken if rubber seals are used on the
vessel, as the CO2 may dissolve in the rubber, causing swelling, and the rubber will rupture on depressurization.

The pressure in the system must be maintained from the Compressor right through the pressure vessel. This can
be either a capillary tube cut to length, or a needle valve, which can be adjusted to maintain pressure at different
flow rates. In larger systems a backpressure regulator will be used, which maintains pressure upstream of the
regulator by means of a spring, compressed air, or electronically driven valve. Whichever is used, heating must
be supplied, as the adiabatic expansion of the CO2 results in significant cooling. This is problematic, if water or
other extracted material is present in the sample, as this may freeze in the restrictor or valve and cause
blockages. The supercritical solvent is passed into a vessel at lower pressure than the extraction vessel. The
density, and thus, dissolving power, of supercritical fluids varies sharply with pressure, and hence, the solubility
in the lower density CO2 is much lower, and the material precipitates for collection. It is possible to fractionate
the dissolved material using a series of vessels at reducing pressure.
This is an important aspect. The fluid is cooled before pumping to maintain liquid conditions, and then heated
after pressurization. As the fluid is expanded into the separator, heat must be provided to prevent excessive
cooling. For small-scale extractions, such as for analytical purposes, it is usually sufficient to pre-heat the fluid

10. in a length of tubing inside the oven containing the extraction shell & tube type heat exchanger can be used. The
restrictor can be electrically heated, or steam heater with shell & tube type heat exchanger. For larger systems,
the energy required during each stage of the process can be calculated using the thermodynamic properties of
the supercritical fluid. For CO2 Flow measurements the Coriolis mass flow meter should be used. The
volumetric flow meter reading changes as temperature changed. The process flow diagram as shown in the
figure-6.

Figure No. 6(Flow diagram of Super Fluid Extraction)
Compressed Carbon di oxide at this point has the density of a liquid, but the properties of a gas. As such this
aids in faster diffusion of the phytochemicals (almost twice that of other liquids), whilst the liquid-like state
helps in better solubility of the phytochemicals. Once the extraction is complete, the pressure is released and the
Carbon di oxide is harmlessly released. In reality, the raw botanical is placed into the extractor vessel. Liquid
Carbon di oxide is heated to its' supercritical state, and pumped into the extractor. The Super critical carbon di
oxide mixes with the botanical, and carries the desired extract into a separator tank, where pressure and
temperature are controlled. The extract is precipitated in the separator, and Carbon di oxide is recycled into the
extractor via a condenser.
Advantages of Supercritical Extraction Method
Soon after recognizing that supercritical carbon dioxide had a future as a solvent, scientists began seeking ways
to get a larger variety of molecules to mingle with the Carbon di oxide. However, since SCF-CO2 is non-polar,
many contaminants will not stick to it. Thus, to find a Carbon di oxide-loving surfactant (a surface active
solution) with one end adhering to Carbon di oxide and the other end to the contaminant of concern, creative
chemical research was needed. Researchers looking for solutions to the surfactant solution have recently found
that by using a co-solvent with the Carbon di oxide, contaminants can be easily extracted. Currently, fluorine
has been found to be the most effective co-solvent. CO2 is inexpensive, not combustible, not explosive,
germicidal, free of bacteria, selective and mobile. Heat sensitive materials are gently treated. Products and

11. residues are solvent-free. Fragrances and aromas remain unchanged. An excellent flavour profile is achieved.
Pure extracts are produced by few process steps. The solvating power can be changed (conditions,
modifiers).Selective extraction and fractionated separation is possible.CO2 is recycled within the plant, is
physiologically harmless and does not cause environmental problems like some conventional solvents.

Conclusion
Supercritical fluid extraction with Carbon Dioxide is a sustainable eco-friendly technology which allows the
extraction of Azadirachtin (C
35H
44O
16) compounds at low temperature without toxic organic solvents. This article
presents the role of SFE as a rapid, reliable and new advanced method, its practical aspects regarding the
extraction processes and comparison with the existing conventional of extraction solvent method. Super fluid
Extraction process can also be designed for acquiring better information for increased extraction yield and
optimization of the process involved in the isolation of compounds related to pharmacy, food and agricultural
significance. Even though the SFE is sometimes criticized for the large number of factors which should be
optimized for every extraction and its high cost, reproducibility, adaptability of supercritical fluids to various
separation processes, advancements in the technology and final outcome makes Super Fluid Extraction
technique one of the best in isolating the bioactive compounds. Potentiality of this technique can further be
exploited for providing the technological and low cost benefits for increasing the quality of the bioactive
compounds in an eco-friendly environmentThis approach has not only resulted in the maximum oil yield
through solvent extraction, but has also guaranteed the fulfilment of the properties requirements of the neem oil
.The optimum values for yield, pH, refractive index, acid value, iodine value and Saponification value from the
surface plot was 43.48%, 4.99, 1.56, 1.411g/g, 89.35g/g, and 176.64 mg/g respectively. Engineering practices
that require traditional solvents are no longer the only option. Through new focuses, such as pollution
prevention, solvent use is being steadily replaced with more environmentally friendly methods. Supercritical
carbon dioxide offers many advantages over traditional solvents. Extraction processes can achieve the same
results without the negative side effects of large waste streams and work place hazards from working with
carcinogenic materials. These advantages have been encompassed by the food and beverage industry and are
making their way into more technical fields. It is non-toxic to humans, birds, earthworms or animals. Being oil
it can affect some beneficial insects if it is actually sprayed on them so it is recommended to use it prior to
releasing beneficial or to conduct a trial to observe its effects on the organism prior to large-scale use. Once the
spray has dried it will not hurt most beneficial organis ms, including lady beetles, lacewings, orius bugs, and
predatory mites.

References
1. A Search for Alternative Solvent To Hexane During Neem Oil Extraction Volume 4 No. 4, April 2014
by Ayoola A.A., Efeovbokhan V.C., Bafuwa O.T. and David O.T
2. Optimization of Neem Seed Oil Extraction Process Using Response Surface Methodology Vol.2, No.6,
2012.