csir, ihbt (2010) A PORTABLE MINI DISTILLATION APPARATUS FOR THE PRODUCTION OF ESSENTIAL OILS AND HYDROSOLS. 1004/DEL/2000.

Preview

PDF Download (40Kb) | Preview

Abstract

The present invention relates to a portable mini distillation apparatus for the production of essential oils arid hydrosols. This apparatus is useful to distill essential oils and hydrosols such as rose water, ajowain water from fresh and dried plant material like leaves, flowers, roots and rhizomes by water distillation, water & steam distillations and as an optional, steam distillation can also be performed at atmospheric pressure as well as slightly higher and lower than atmospheric pressure. This unit can be heated on brick-clay furnace with small agro-waste, LPG cooking gas, electrically heated stove or kerosene/diesel burner etc., and requires minimum attention during handling. Since the apparatus is made of stainless steel and glass, the essential oil distilled is of better quality than the oil distilled by glass Clevenger type apparatus used in the laboratory. A laboratory equipment used for distillation of essential oils is called Clevenger type apparatus as shown in Fig. 1 of the drawings accompanying this specification. Reference may be made to Clevenger type, J.F., Apparatus for the determination of volatile oil. J. Amer. Pharm. Assoc., 17, pp. 346(1928), wherein the apparatus (I) is attached to the spherical glass vessel (a) having charged with the plant material along with water in 1:2 ratio through opening (b) which is also used for discharging the mixture after process is complete. The whole system is put on a heating mantle (c), which has an energy regulator (d) for controlling the temperature. After few minutes, the material inside starts boiling. The vapours so formed are passed through a vertical condenser (e) through a long vertical glass tube (f). The cold water around the condenser tube is circulated through inlet (g) and outlet (h). The condensed distillate gets collected in a measuring tube (i) connected to the outlet of the condenser where an air outlet (j) open to atmosphere is placed. The volatile oil separates as an upper layer, from the distillate because of its density difference, as the oil is lighter than the water. A return tube (k), for recycling of aqueous part of the distillate, connects the bottom of the measuring tube (i) and vertical tube (f). The oil is collected at the outlet by opening the stop-cock valve (1). The major drawback of the apparatus is that it was designed to distillate the plant material by water distillation at normal atmospheric pressure only. There are some aromatic plant materials exclusively distilled by steam distillation method rather than water distillation, reason being that some of volatile constituents get hydrolysed due to the presence of excessive water in the vessel. The apparatus works neither on the principle of steam distillation nor on water & steam distillation technique. Clevenger type apparatus is generally restricted to laboratories for the essential oil estimation but cannot be used to produce the essential oil in higher quantities. Since the system is heated up with the help of electric mantle (c) only, with very small batch capacity of material charging vessel (a), long vertical glass tube (f) and condenser (e) are made up of glass which requires careful handling and can not be heated without electricity which is difficult for a marginal farmer with small land holdings in remote areas. The recovery and quality of the essential oil distilled in this glass Clevenger type apparatus is of inferior quality. The colour of the oil is generally lighter than the commercially distilled oil which is not recommended in the market. There are distillation units which are operated by Water & Steam distillation method. Water & Steam distillation method involves a distillation tank with a false bottom and with or without Calendria at the bottom, cohobation column at the top which is connected to the condenser and a distillate receiver. The plant material is charged from the charging hole and closed tightly. Prior to charging of plant material some fresh water is added to the tank and the precautions are to be taken to control the water level which should not touch the false bottom. The water level is maintained by recycling the distillate collected in the receiver to the tank or a continuous or batch-wise fresh water is supplied to the tank. The tank is heated by direct firing of the agro-waste from the hearth bellow. The purpose of this method is to reduce the effect of hydrolysis of essential oil which are get hydrolysed when they came in to continuous contact with excess water. After few minutes the water vapours starts .forming and extracts the essential oil from the plant material and carries it over to condenser where they are condensed to liquid distillate. The distillate is collected in a receiver where it is separated in to two fractions; one as an essential oil and other as a saturated water layer. The essential oil is separated, cleaned and then stored as per the recommended methods. The major drawbacks of the unit are that it can jiqt distill thejpj.ant material by Steam distillation. Some parts of the aromatic herbs such as cedar wood, sandel wood are preferably distilled by Steam distillation method to obtain better recoveries and quality. Also these units can not distill the plant material neither at reduced pressure nor at higher pressure since the system is opened to the atmospheric pressure and can not operated as a closed system. Being an industrial size these units can not be a portable systems and thus difficult to take them to the fields where the plant material is available in remote areas and distilling the fresh raw material is not possible in such a system which is one of the major parameter in affecting the quality of an essential oil. Being commercial scale units they requires more man power, operational costs etc., and the marginal farmers can not afford to purchase these industrial scale distillation units. The widely used hydrodistillation method in the essential oil industry is Steam distillation. The units used to perform the Steam distillation method merely consists of a distillation tank with a false bottom fixed at a certain height from the bottom of the tank. A spurger is provided below the false bottom which is connected to the industrial size boilers. The plant material is placed above the false bottom and then the lid is closed tightly by nut-bolts. Steam generated from the boiler is fed to the tank through the fixed steam spurger to commence the distillation. After few minutes the vapours starts forming which are taken to the vapour inlet of a shell and tube condenser which is connected to the vapour out let of the distillation tank at the top. The condensed liquid is collected in a receiver where the essential oil and distillate are separated. The major drawbacks of the unit are that it can not distill the plant material neither by Water distillation nor by Water & Steam distillation. Some parts of the aromatic herbs are preferably distilled by Water distillation method to obtain better recoveries and quality. Also these units can not distill the plant material neither at reduced pressure nor at higher pressure since the system is opened to the atmospheric pressure and can not operated as a closed system. Being an industrial size these units can not be a portable systems and thus difficult to take them to the fields wnere the plant material is available in remote areas and distilling the fresh raw material is not possible in such a system which is one of the major parameter in affecting the consistency in the quality of an essential oil. Being commercial scale units they requires more man power, operational costs etc., and the marginal farmers can not afford to purchase these industrial scale distillation units. Thus, apparatus, industrial scale units and the process mentioned above has one or the other major drawbacks like inferior oil quality, low oil recovery, low batch capacity, lack of Water distillation, Steam distillation and Water & Steam distillation facility, restricted mode of heating, unable to distill the plant material under vacuum and at higher pressures, difficulty in charging and discharging of plant materials because of narrow mouth and requires more attention during processing, more capital investment, operational cost. The main object of the present invention is to provide a simple, convenient, portable mini distillation apparatus for the production of essential oils and hydrosols, which obviates the drawbacks as detailed above. Another object of the present invention is to provide an apparatus for the distillation of essential oils having capacity little higher than the laboratory scale apparatus to meet the needs of marginal farmers. Still another object of the present invention is to provide an apparatus for the distillation of essential oils, if required, slightly at higher and lower pressures than atmospheric pressure. Yet another object of the present invention is to provide an apparatus for the distillation of essential oil by water distillation, water & steam distillation and steam distillation on small scale. Another object of the present invention is to provide an apparatus for the production of perfumed water from aromatic plant material at small scale. Still another object of the present invention is to provide an apparatus for the production of distilled water from the tap water or natural sources for lab use or for other purpose. Yet another object of the present invention is to provide portable and convenient apparatus for effecting distillation even in the fields or remote farming areas. Another object of the present invention is to provide an apparatus for the production of quality grade essential oils at house hold scale as a cottage industry to suit the marginal farmers/entrepreneurs who can not afford to install bigger capacity units. In fig. 2 of the drawings accompanying this specification, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The present invention essentially consists of main parts such as a distillation vessel (1); a cohobation column (8), condenser (11) and oil retention column (13) with recycle line (16) connected to the cohobation column (8). Accordingly, the present invention provides a A portable mini distillation apparatus for the production of essential oils and hydrosols comprising one or more vessel(s)(l) having conventional means for heating internally/externally, the said vessel characterized in that a threaded rod (6) being fixed concentrically inside bottom of the said vessel(s) so as to allow vertical movement of a sieved false bottom(5,7), one or more steam spurger(s)(24) being provided between the said vessel bottom (2) and the said movable false bottom, the said vessel(s) being provided with removable fixed lid(s)(3) having a safety valve(s)(21), housing(20) for fixing pressure/vacuum/temperature guage and a vapour outlet(s)(9), the said vapour outlet(s) being connected to the inlet of one or more vertical cohobation column(s)(8), the outlet(s) of the said cohobation column(s) being fixed to the inlet(lO) of a conventional condenser(ll) provided with closeable vent(15), outlet(12) of the said condenser being detachably fixed by clamp(14) to a vertical receiver-cum-separator column(13) having a valve(18) controlled outlet(23), the bottom and middle of the said receiver-cum-separator column being provided with a plurality of valve(17,19) controlled recycling pipes (16) connected to the upper portion of the said L nation column (s). In an embodiment of the present invention, the vessel is heated internally by means of known electrical heating system and externally by any conventional/non-conventional beatings means. In another embodiment of the present invention, the vessel has a height to diameter ratio in the range of 0.5 to 1.5. In yet another embodiment of the present invention the vessel, cohobation column, condenser and recycling pipes are made up of metal such as stainless steel, copper, tin. In still another embodiment of the present invention the receiver-cum-separator column is made of glass, coated with transparent plastic or covered with an aluminum casing. In yet another embodiment of the present invention the closeable vent (15) of the condenser is optionally connected through a valve to a vacuum pump. The present portable mini distillation unit provides a simple, convenient, portable apparatus for the distillation of essential oils which comprises charging of aromatic plant material along with water in the ratio in the range of 1:0 to 1:2 in the vessel (1) through the charging hole, as described above and depicted in fig. 2, depending upon the type of the distillation process to be used. Place the gasket properly above the flange of the still, tighten the lid by quickfit joint (4) and attach the cohobation column (8), condenser (11) and glass tube (13) with the lid by tightening the union (9) after ensuring the proper setting of the gasket, place the whole system above the direct fired furnace/LPG burner/Kerosene or Diesel stove for heating the vessel (1). Fill the shell side of the condenser with water and the optimum water flow rate, for the total condensation, was maintained. Fill the oil retention glass tube (13) with water through air vent (15) at rear end of the condenser (11) until water starts flowing in to the cohobation column (8) through recycling line (16). The air vent (15) on the condenser (11) is opened throughout the process, if the plant material is to be distilled at atmospheric pressure and remain closed if the plant material is to be extracted under pressure. The valve (19) on the recycle line is kept opened throughout the process if essential oil only is to be distilled and remain closed if only perfumed distillate required. Now start heating the vessel (1) with any heating means mentioned above. Vapours start forming/ a few minutes later and enter to the condenser (11) through cohobation column (8) where they are condensed and collected in the glass tube. The essential oil in the distillate settles as an upper layer over the lower layer of water as the case may be. The aqueous part of the distillate is recycled, to the cohobation column (8) through the recycling line (16) if the essential oil is lighter than the water otherwise, it is recycled through the other pipe line shown in the fig. 2 as a dotted line. In order to recover the dissolved oil, the process is continued for 3 to 5 hr depending upon the type of plant material and distillation performed. After the completion of process, the essential oil is collected from the outlet (23) of glass tube (13) by opening the valve (18). The collected oil is measured and dried over anhydrous Na2SO4 filtered and then can be stored in aluminium bottles. The constructional features of an embodiment of the apparatusof the present invention are given below : A stainless steal (SS) - 304 vessel (1) having internal diameter (ID) = 325 mm, height = 325 mm with slightly curved bottom (2) and wide mouth ID = 325 mm for easier charging and discharging plant material is to be distilled, above which a conical lid (3) with base diameter =325 mm, vertical height = 150 mm, slant height = 210 mm to which a flange ID = 325 mm, outer diameter (OD) = 350 mm, is welded. The lid is attached to the vessel by a quick-fit joint (4). The material of construction (MOC) of lid (3) is stainless steel (SS) -304. A false bottom (5), 320 Φ, 2 mm thickness (thk.), with 2 Φ holes in Δle pitch and 10 Φ hole in the center to fit in the threaded SS rod (6) with 10 Φ for adjusting up and down according to the plant material charged. A circular strip (7) ID = 315 mm, OD = 325 mm welded to the vessel at a height of 35 mm from the bottom end to hold the false bottom. At the top of conical lid (3), a stainless steel cohobation column (8) is fixed with the help of union (9). The cohobation column (8) ID = 50 mm up to at a height of 780 mm which is reduced to ID = 40 mm upto a length of 215 mm and slant height of the reducer is 40 mm. The outlet of the column, ID = 40 mm, is welded to a bend (10) having same ID. The bend is again welded to a stainless steel horizontal shell and tube 1-1 heat exchanger (condenser) (11) with ten number of SS s

Item Type:	Patent
Subjects:	Plant sciences Natural Product Chemistry
Divisions:	UNSPECIFIED
Depositing User:	Dr. Aparna Maitra Pati
Date Deposited:	07 Jan 2013 11:29
Last Modified:	07 Jan 2013 11:29
URI:	http://ihbt.csircentral.net/id/eprint/1031

Actions (login required)

View Item