|Title of Invention||
A POWDER FOR PURIFICATION OF USED OIL AND PROCESS FOR PURIFICATION OF USED OIL
|Abstract||The invention deals with a powder for purification of used oil and process for purification of used oil. In the present invention, a mixture has been prepared which along with adsorbents carries some of the specially treated clays having cationic and anionic monolayers. The components used in the powder are: Magnesium carbonate basic light, Magnesium oxide light, Bentonite powder, Refoil optimum grade clay, activated clay 303 and activated clay star. To make the powder more effective, chemisorbents have also been added which will neutralize some of the acidic and alkaline matter produced. This unique combination employs physical and electrochemical forces to purify the repeatedly heated oils, either in native form or in the form of the blend. Furthermore, the treatment process is made much simpler so that it can be used in domestic or commercial kitchen without taking the help of an equipment or a gadget.|
|Full Text||Field of invention:
The present invention relates to a process for production of edible vegetable oils
Background and prior art of the invention:
Deep frying is a process where food items are fried in a vegetable oil at an elevated temperature (175-185°C). Frying oils are exposed to atmospheric oxygen and food moisture at elevated temperature for long period of time, during the frying process. As a result various chemical transformations take place in the oil. This produces a number of harmful compounds and drastically changes the oil quality. After deep frying, oil is generally reused several times to fry new portions of same or different food items, decreasing the useful life of vegetable oils. These changes not only cause inconvenience in frying but also affect the quality of final products, bringing about changes in its color, appearance, texture and flavour. Since, degeneration of oil quality is unavoidable, normally in commercial catering and even in house hold, either the oil is discarded or reused again and again by adding fresh batch of oil to minimize the concentration of deleterious components developed. In addition frying oil picks up particulate and soluble contaminants and food juices from the food being fried. These impurities in oil causes certain undesirable properties like increase in viscosity, darkening of colour and foaming. It results in decrease in smoke point, increase in free fatty acids, carboxyl value and decrease in unsaturation. Keeping above problem in mind a powder has been developed which can clean up this ready to be discarded oil. This purification powder consists of activated earth, adsorbents and chemisorbents which are inert in nature and do not interfere with oil composition. The purified oil can then be used as such or after dilution with much less of deleterious substances.
Reference may be made to Davies M.E., Whittle M.E., Janes W. and Mokaya R., Pillard clays, United States Patent, US. 5486499, 1996 where in a process for the production of an adsorbent suitable for use in the purification of edible oils such as soya oil comprising treating a layered clay mineral with a solution of a pillard material is given. These materials are suitable aluminium cations which cause the adsorption of at least some of the polar material into clay mineral and removing deposit pillared material within the clay mineral. The process being characterized by the removal of at least some structural aluminium from the clay mineral. The resulting pillard material, which can have a higher SiCh: AI2O3 ratio than normal as a result of the initial acid treatment can give chlorophyll adsorption capacity above 70% and even, in some instances, upto about 99%. The main draw back with the above report is that a combination of clay is used for purification of raw soybean oil which can be termed as refining of soya oil. This does not relate to purification of heated oil which can increase the frying life.
Reference may be made to Sokolsky D.V., Zhubanov K.A., Shumateva N.F., Mazin E.P. and Sokolskaya A.M., Adsorbent for purifying vegetable oils from phosphorous containing compounds, United States Patent, US 3862054, 1975 wherein a granulated composition comprising 5 to 50 percent of metal oxide of Group II or of Group III of the periodic table or a mixture there of, and 10 to 40 percent by weight of a cement which is heat resistant at 500C and above, and 10 to 85 percent by weight of alumina or a clay free from iron oxide have been given. The adsorbent is prepared by mixing an aqueous solution of a salt of said metals with an aqueous soda or alkali solution while simultaneously depositing, with stirring, the resulting carbonates, or hydroxides of said metals on to the alumina or clay. The coated filler is separated to give a paste-like mass
which is mixed, with stirring with the cement and water granulated, dried at 20° to 150°C and calcined at a temperature of from 300° to 500°C. The adsorbent may be regenerated quite easily and has a high mechanical strength up to 150 kg/cm . The use of this adsorbent for the purification of vegetable oils makes it possible to reduce by 500 times the usual adsorbent consumption, eliminate separating oils from the adsorbents by filtration, and increase by 2 to 2.5 times the service life of catalysts employed in hydrogenation of oils. This composition of adsorbents also work as a refining tool. The details of a process for production of fuller earth is given rather than purification of oil. This process work as a refining process and there is no information on the purification of heat abused oils.
Reference may be made to kerdivarenko M.A., Vrednik I.M., Dulneva LP. and Sheremet, N.V., Treatment of frying oil with powdered natural adsorbents, Izvestiya - Vysshikh-Uchebnykh-Zavedenil-Pishchevaya-Tekhnologiya; No.4,37-40,1981, wherein the efficacy of adsorbent with different particle size has been studied. The efficiency of the adsorbent increased with decreasing particle size, with best results at particle size less than 0.1 mm. Similar results were obtained with 0.2 - 0.1 mm particles, which are easier to separate from the oil. Adsorptive contact purification of oil is effected within the initial 10-15 seconds of contact, regardless of the degree of communication of the adsorbent. The sequential oil can be used for frying vegetables. The drawback with this work is that it describes the adsorption powder in detail but does not give information regarding the purified oil.
Reference may be made to Friedman B., Means for treating fats and oils and methods for treating used cooking oil, German-Federal-Republic-Patent-Application, 1981, wherein used fats and oils are treated with a mixture containing water and porous rhyolite carrier
and (optionally) a food type acid. The composition preferably contains 27-76 wt % carrier and 33-75 wt % of a solution containing 2-10% acid. This removes the impurities from the used cooking oil fat so that it can be reused. The treatment time is short, and the materials can be removed by simple filtration without the need of an elaborate equipment. The drawback with the formulation is that it uses water alongwith rhyolite. Adding a water based formulation to the oil is technically not correct as it triggers the hydrolysis of oil in further application, which is not desirable.
Reference may be made to Scavone T.A. and Braun J.L., High temperature vacuum distillation process to purify and increase the fry-life of edible oils, United States Patent US 4 789 554, 1988, wherein de-aerated oil having a level of less than 0.10% by vol. dissolved oxygen is heated at 277°-343°C and stripped with a stripping medium with a molar ratio of stripping medium to oil of about 0.05-9.7, at an absolute pressure of about 0.5-50 mm Hg, for about 5-15 min. This process improves the fry-life of the oil while minimizing undesirable thermally induced side reactions. The drawback with this process is that it does not specify that whether it is for oil refining or for heated oil purification. In addition, it is a different approach altogether.
Reference may be made to Mgebrishvill T.V., Artyuskov V.N., Martorsochuk V.I. and Dekhtesman D.A., Method for purification of vegetable oil, USSR Patent, 594 163, 1978, where in the vegetable oil is hydrated, heated at 210°-230°C and citric acid is added along with sodium acetate, the mixture is allowed to stand for 3-5 min. and then is neutralized with alkali. The non-triglyceride matter coagulate out. The process of heating and acid treatment are carried out under vacuum preferably at 40-70 mm Hg. The citric acid and sodium acetate mixture is preferably in a 1:1 ratio. This is a modified
process of purification of vegetable oil, where raw oil is taken and purified to make it edible. No attempt is made to purify a heat abused oil.
Reference may be made to Mir oil fry powder oil stabilizer, US Department of Labor, Occupational Safety and Health Administration, 602-20 North Tacoma street, Allentown, PA 18 109, USA, wherein a fry powder oil stabilizer and filter aid has been reported which consists of citric acid, a naturally occurring compound which is distributed in plant and animal tissues. The citric acid is blended with mineral which is perlitic and inert in nature. The mineral is flame expanded by a proprietary process and described as "Food compatible material" and is claimed as GRAS. This fry powder is not soluble in water, granular and odorless in nature, having no harmful reactions. The drawback with the fry powder is that it is not exclusively meant for purification of repeatedly heated/fried oils. It has to be added regularly to the qualitatively sound frying oil to achieve benefits including low oxidation rate and low oil uptake by the products hence, not directly related to purification powder, we have invented. The above discussed processes and adsorbent powders including Mir oil fry powder though useful but are not as effective as the process for purification using purification powder, reported in present invention, for purification of repeatedly heated vegetable oils. Some of the processes are just a partial refining process using different apparatus and adsorbents to purify raw vegetable oils. In some cases, water is used which is not a good proposition. Mir fry powder, which is a latest addition, has to be used since beginning of the heating to enhance the fry life of oil. Objects of the invention:
The main object of the present invention is to provide a process for production of edible vegetable oils purification powder which obviates the drawbacks as detailed above.
Another object of the present invention is to remove the oxidized and polymerized
products, which are generated in situ, from the purified oils.
Still another object of the present invention is to provide a process for purification of
repeatedly heated oils which are ready to be discarded.
Summary of the invention:
The present invention deals with an process of preparation of purification
Powder and purification of fried oil, using the purification powder.
Detailed description of the invention:
Accordingly the present invention provides a process for production of edible
vegetable oils purification powder which comprises of the constituents like activated
carbon, silica gel, alumina, keiselgur, magnesium carbonate, magnesium oxide, bentonite
powder, refoil activated optimum grade, activated clay 303, activated clay star, all or few
of them in the weight ratio between 1 g to 10 g and 10 g to 200 g each in increasing
order, which has been heat treated, surface activated in the cationic and/or anionic
monolayer form at 75-150°C, cooled and used for purification of heat treated oil, which
comprises of the following steps:
a) Treatment of repeatedly heated, ready to be discarded, frying oil, between 100 to 1000 ml, with purification powder.
b) By mixing purification powder which consists of treated and modified clay, adsorbents and chemisorbents
c) Where ratio of oil to purification powder falls between 1:1 to 20:1 wt/wt
d) And the treatment time ranges between 1 to 10 hours at 30° to 200°C
e) After treatment the heat source is cut off and purification powder is allowed to settle down
f) The treated oil can be separated from the purification powder by convenient means to yield purified oil
g) The purified oil can be reused as such or as a diluent.
In an embodiment of the present invention, a purification powder have been prepared using clay, various adsorbents and chemosorbents which have been found to remove free fatty acids, peroxides, hydro peroxides and polymers from the heat abused vegetable oils in a set conditions.
In another embodiment of the present invention, various frying oils like groundnut, sunflower, mustard and palmolein oils, and their blends with sesame oil, a known thermostable vegetable oil, which are repeatedly heated in a controlled condition generating oxidation and polymer products have been purified using a purification powder prepared in the laboratory.
Most of the vegetable oils which are used for cooking are also used for deep frying in India which is not a good practice. Oils during frying or heating are exposed to elevated temperature in the presence of moisture. Under these conditions, changes like hydrolysis, oxidation, thermolysis and polymerization take place. These phenomenons along with volatiles and non-volatile components have bad effect on flavour, colour and texture of fried foods as well as fry life of the oils. The decomposition products and rate of their formation vary with the nature of the fat used, the surface volume ratio, the excess of air, the nature of food fried and interval of heating. The artifacts produced are carcinogenic in nature and also cause irritation to mucosa membranes. Hence, it is better to discard such repeatedly heated oil rather than reuse it as such or as a diluent. In order to reduce the detrimental effects and prolong the useful life of frying oils, regular cleaning, maintenance of equipment and utilization of proper frying conditions are required.
Recently, the fast food industry is adopting various methods of maintaining the quality and increasing the useful life of frying oils. Many methods have been tried for purification of heat abused vegetable oils. For example, a cleaning system with a filter, which helps in removing the fried food fractions, thereby, is reducing the further degradation of oil. The filter paper lies between the oil inlet and outlet positions, so that the oil passes through the filtering media, which will remove impurities sediments from the oil. But it is not so effective if viscosity of oil increases due to repeated heating. Therefore, it would be highly desirable to provide a purification aid which overcomes these disadvantages and have the ability to remove undesirable impurities, physical as well as chemicals from the oil and restores desirable cooking properties, in the used frying oils.
The primary function of acid activated bleaching earth in the adsorption purification of edible oils is to enhance finished oil quality. The desired improvements are achieved because acid-activated bleaching earths possess a pronounced capacity for adsorbing various trace constituents from frying oils, including soaps, metals, color pigments, phospholipids, primary oxidation products i.e. peroxides, hydro peroxides, and secondary oxidation products like aldehydes, ketones and acids. But the amount and composition of adsorbents added varies greatly depending upon a large number of factors, including the amount of impurities in the oil, the type of oil being treated, the temperature of the oil etc. The temperature of the oil during treatment should be such that it should cause release of water from the porous carrier resulting in effective dispersal of the carrier throughout the hot oil.
But in the present invention, a mixture has been prepared which along with adsorbents :arries some of the specially treated clays having cationic and anionic monolayer. To make the powder more effective, chemisorbents have also been added which will neutralize some of the acidic and alkaline matter produced. This unique combination employs physical and electrochemical forces to purify the repeatedly heated oils, either in native form or in the form of the blend. Furthermore, the treatment process is made much simpler so that it can be used in domestic or commercial kitchen without taking the help of equipment or a gadget.
The following examples are given by way of illustration of the present invention and therefore should not be constructed to limit the scope of the present invention.
Eight different edible vegetable oil samples namely sunflower oil, groundnut oil, mustard oil, and blends of palmolein, groundnut, mustard, sunflower oils with sesame oil in the ratio of 70:30 v/v were taken for study. However, among them two of the sunflower oil samples have already been used for repeated deep frying in commercial caterings have also been included for purification purpose: The above four laboratory made blends and vergin groundnut and mustard oils, 500 ml each, were taken separately and heated at 180°-185°C for a total of 30, 60, 120 and 180 minutes with the gap of 3 days each. This intermittent heating was done to mimic the deep frying process at home and also to give sufficient number of heating and cooling treatments.
Purification of repeatedly heated oils using activated carbon:
The repeatedly heated eight oil samples, 100 ml each, which included four health oil blends, virgin groundnut and mustard oils and two sunflower oil samples obtained from commercial caterers as described in example-1 were taken separately in a 250 ml capacity round bottom flasks. In each oil samples 20 gms of pre activated (heated at 110°C for 1 hour) carbon have been added and mixed thoroughly. The content was heated at rotamental at 90°-95°C for 7 hours with occasional stirring. After the treatment was over, the mixture was filtered through Whatman No.41 filter paper. The purified oil obtained was used for physico-chemical and spectral analysis. Results are given in Table-1.
Table 1: Physico-chemical and spectral characteristics of repeatedly heated (control) and corresponding purified vegetable oils using activated charcoal as purifying agent.
* P = Palmolein, G = Groundnut oil; M = Mustard oil, S= Sunflower oil; SE = Sesame oil, RES = sunflower oil from restaurant; CS = Sunflower oil from Dept. canteen. ** Frequencies other than normally observed for glycerides i.e. 3400-3480, 2854-3008, 1740-1750, 1620-1680, & 1430-1470.
Table-1 reveals that free fatty acids and peroxide value of heated oil samples ranged between 2.0 to 0.4 and 52.8 to 8.8, which after treatment with activated carbon could be brought down to 1.6 to 0.2% and 4 to 1.7 meq. 02/kg of fat respectively. All the samples were found to be devoid of moisture as all of them were heat treated. Ultra-violet spectrum showed absorbance at Xmax 230-232 nm for the peroxides and conjugated fatty acids, generated during thermal oxidation, in all the heated samples, maximum being 2.8 for the oil sample obtained from the commercial catering. But among the laboratory samples, sunflower oil blend, also showed a strong absorption up to 1.4. However, after purification, it has come down between 0.2 to 1.1 which indicates positive cleaning effect, though moderate. Infra-red spectrum could not give a clear picture as absorption frequency band for hydroxyl and associated hydroxyl were present in all the heated samples as well as purified samples except in case of purified palmolein blend which showed its higher stability compare to other blends.
Purification of repeatedly heated oils using silica-gel:
Silica gel for column chromatography, 60-120 mesh, is basically an adsorbent which is used for column chromatographic separation of organic mixtures. But in the present study, it has been used as a purification agent utilizing its ionic surface activity. It can attract ionic components of opposite polarity including the free radicals and bind them with itself in the native form, in absence of an organic solvent. Hence, use of silica gel is an unconventional technique for purification of heat abused oils. The eight repeatedly heated vegetable oils (100 ml each) as prepared in example-1 were taken in 250 ml capacity round bottom flasks separately. In each flask, 20 gms of pre-activated (heated at 110°C for 1 hour) silica gel for column chromatography, 60-120 mesh, have been added and content mixed thoroughly. The content was heated with constant stirring at 90°-95°C for 7 hours. After the treatment is over, the mixture was filtered through Whatman No.41 filter paper. The purified oil obtained was used for physico-chemical and spectral analysis. Results are given in Table-2.
Table 2: Physico-chemical and spectral characteristics of repeatedly heated (control) and corresponding purified vegetable oils using silica gel as purifying agent.
* P = Palmolein, G = Groundnut oil; M = Mustard oil, S= Sunflower oil; SE = Sesame oil, RES = sunflower oil from restaurant; CS = Sunflower oil from Dept. canteen.
** Frequencies other than normally observed for glycerides i.e. 3400-3480, 2854-3008, 1740-1750, 1620-1680, & 1430-1470.
Table-2 shows that free fatty acids and peroxide value of heated oil samples ranged between 2.0 to 0.4 and 52.8 to 8.8 which after treatment with activated silica-gel came down to 1.6 to 0.3% and 21.6 to 11.7 meq. C^/kg of fat respectively. These value indicate that although there is a decrease in FFA % but peroxide value have not decreased considerably which also have been reflected by Infra-red spectrum which showed absorption band for hydroxyl in all the purified samples except for palmolein blend. Although ultra-violet spectrum have not shown any absorption maxima at 230-232 nm for palmolein, groundnut, and mustard oil blends and a market sunflower oil sample, but it did show for laboratory sunflower oil blend and market sunflower oil indicating that purification was not as effective as in case of purification by activated carbon. However, palmolein oil blend was found to be most heat stable.
A powder has been prepared using bentonite powder, Refoil activated optimum grade, activated clay 303 and activated clay star, mixing them thoroughly in the ratio of 1:2:3:4 wt/wt in a pestle mortar. The powder has been activated in a hot air oven at 110°C for 2 hours. The activated powder 10%, w.r.t. weight of the oil, has been added to 500 ml of repeatedly heated sunflower oil: sesame oil blend in a round bottom flask. The contents were mixed thoroughly and heated at 100°C for 7 hours. After the treatment of oven, the mixture was filtered through Whatman No.41 filter paper. The purified oil has been subjected for free fatty acids and peroxide value estimation. The PV could be brought down from 52.8 to 20.3 but the change in FFA was nominal from 2.0 to 1.8%. However, there was improvement in color after treatment.
Another set of chemosorbents and adsorbent namely magnesium carbonate basic light, magnesium oxide light and bentonite powder in the weight ratio of 1:2:3 were taken and mixed together thoroughly. The mixture was activated and tried at 110°C for 5 hours before use in desiccated conditions. Ten percent of the powder has been added to 500 ml of the repeatedly heated sunflower and sesame oil blend in a round bottom flask. The content was heated at 95-100°C in constant agitated conditions. The treatment was given for 5 hours. After the treatment the oil was separated by filtration. Free fatty acids percent could be brought down from 2.0 to 0.9 but peroxide value was 40.1, a decrease of 11.7 units only indicating not a good effect of purification powder.
Two chemosorbents like magnesium carbonate and magnesium oxide and two clay like
activated clay 303 and activated clay star have been taken in the ratio of 1:1:1:1 and
mixed thoroughly. The mixture was subsequently activated in a hot air oven at 110°C for
5 hours and kept in a desicator for cooling. The purification powder (50 g) added to
repeatedly heated sunflower and sesame oils blend in a round bottom flask and mixture
was heated with occasional stirring at 110°C for a period of 5 hours. Work up was done
as before. The resultant oil was low in FFA (from 2.0 to 0.8) but not so low in PV (52.8
Another purification powder has been prepared, which consisted of magnesium carbonate
basic light, magnesium oxide light, bentonite powder, refoil activated optimum grade,
activated clay 303 and activated clay star; for the purpose of purification of repeatedly
heated vegetable oils. These constituents have been selected on the presumption that they will be able to remove the thermolysis components including the primary and secondary oxidation products which are generated in the oil during heating or deep fryings. These adsorbents and chemosorbents were taken in equal proportions, mixed thoroughly and brought to the same particle size using a manual blender. This mixed adsorbent purification powder have been activated at 110°C for 1 hour before use.
Purification of repeatedly heated vegetable oils using purification powder:
One liter of repeatedly heated vegetable oil has been taken in a frying vessel and oil heated to 180°-185°C. Mixed adsorbents purifying powder, 50 g, have been added to the hot oil and mixed thoroughly manually or mechanically so as to distribute it all over before finally it settles down at the bottom. After treatment is over, the heat source is cut off and oil is allowed to cool as usual. Oil along with purification mixture kept at room temperature for 8 hours before it is filtered through a cloth strainer. The purified oil can be reused as such or as a diluent. The detail scheme is given in Fig. 1 and results are presented in Table-3.
Repeatedly Heated (ready to be discarded) Frying oil
PURIFIED OIL Fig.l: Purification scheme of repeatedly heated frying oils using purification
Table 3: Physico-chemical and spectral characteristics of repeatedly heated (control) and corresponding purified vegetable oils using mixed adsorbents as
* P = Palmolein, G = Groundnut oil; M = Mustard oil, S= Sunflower oil; SE = Sesame oil, RES = sunflower oil from restaurant; CS = Sunflower oil from Dept. canteen.
** Frequencies other than normally observed for glycerides i.e. 3400-3480, 2854-3008, 1740-1750, 1620-1680, & 1430-1470.
ND - Not Determined
Close examination of table-3 shows, that free-fatty acids and peroxide value of heated oil samples ranged between 2.0 to 0.4 and 52.8 to 8.8 which, after treatment with mixed adsorbent purification powder, has been brought down considerably to 0.4 to 0.1% and 9.0 to 3.8 meq O2/kg of fat respectively. However, anisidine value an additional parameter for secondary oxidation products have been determined which ranged between 33.3 to 15.3 for heated samples and 12.0 to 5.4 for purified samples. These data indicate that efficacy of purification in case of mixed adsorbent purification powder has been found to be maximum compared to carbon and silica gel. These observations have been further supported by ultra-violet absorption at 230-232 nm, for primary oxidation products, which was found to be absent in all the purified oils. Infra-red spectrum of purified oils did not show any absorption band for free or associated hydroxyl, as has been seen in corresponding heated oils, confirming the high efficacy of mixed adsorbents purification powder. Moreover it is also economical as it cost Rs.15/- only for purification of 1 kg of oil.
Glyceride composition of fresh heated and purified sunflower oil frying blends:
Pre-activated silica-gel for column chromatography, 100-200 mesh (30 gms) was mixed
with dry petroleum ether (50-60 ml) in a glass beaker. The slurry was packed in a glass
column, length 45 cms, and diameter 2 cm, with the help of petroleum either. One gram
of oil sample was dissolved in 3 ml of chloroform and loaded on the packed column. The
first, second and third fractions comprising of triglycerides, diglycerides, and
monoglycerides with free fatty acids, were eluted using 250 ml each of 10% diethyl-ether
in petroleum either, 25% diethyl-ether in petroleum ether and 100% pure diethyl ether respectively. The eluent were collected separately for each fraction and evaporated to dryness in tarred 250 ml flask. The fractions were weighed and dried repeatedly unless constant weight was obtained. The values are given in Table-4.
Table 4: Glyceride composition (%) of unheated (fresh), repeatedly heated and purified sunflower oil frying blends:
With the foregoing examples it can be concluded that among the purifying agents used for purification of heat abused oils, the mixed adsorbents purification powder was found to be the best with respect to efficacy of purification and also the ease of application. This pertains to the novelty of the present invention.
The main advantages of the present invention are:
1. A purification powder has been developed which can be used for purification or cleaning of repeatedly heated and ready to be discarded vegetable oils.
2. A purification process has been given which can be clubbed with the last batch of frying in the domestic or commercial kitchen.
3. The powder need not to be added in the oil intermittently as it is a one time (last stage) treatment, after which the powder can be discarded.
4. No equipment is needed for purification purpose as decantation and cloth filtration gives the purified oil in the ready to be used form.
5. This powder or process is capable of removing primary and secondary oxidation products, polymers, along with solid particles in one treatment alone.
6. It can be used by house hold with no energy consumption and training.
7. It does not employ any chemical reaction. It works on purely physical phenomenon. Hence, no change in the chemical composition of the vegetable oils takes place.
8. It does not require any equipment for purification
1. A powder for purification of used oil which comprises atleast three of the following components, wherein the ratio of each component vary in the range of 1-4 : 1-4 : 1-4 and the said component comprising : I. Magnesium carbonate basic light, II. Magnesium oxide light, III. Bentonite powder, IV. Refoil optimum grade clay, V. activated clay 303, VI. activated clay star.
2. A powder for purification of used oil as claimed in claim 1, wherein all the ingredients as claimed in claim 1 are preferably mixed in equal proportions.
3. A process for the purification of used oil using the powder as claimed in claim 1, wherein the said process comprising the following steps :-
a. adding the powder as claimed in claim 1 into the fried used oil in the ratio
of 1:1 to 20:1 w/w,
b. heating the mixture of oil and powder obtained from step at temperature
ranging from 30 to 200 degree C, for a period of 1 to 10 hours,
c. allowing the powder in the heated mixture obtained from step b) to settle
d. separating the oil from the mixture obtained from step c) by conventional
4. A process of purification as claimed in claim 3, wherein the fried used oils are sunflower oil, groundnut oil, mustard oil, and blends of palmolein, groundnut, mustard, sunflower oils with sesame oil.
|Indian Patent Application Number||759/DEL/2005|
|PG Journal Number||22/2012|
|Date of Filing||31-Mar-2005|
|Name of Patentee||COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH|
|Applicant Address||ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI-110001, INDIA.|
|PCT International Classification Number||A23L 1/01|
|PCT International Application Number||N/A|
|PCT International Filing date|