Process Description of Clove Oil Making

Raw Materials

The essential oil content of clove buds, stem and leaves is on average 17%, 6% and 2.5%, respectively.

Water or steam distillations still are popular for the production of clove oil. The first method yields essential oil for perfumery and flavour purposes, and the oil contains 85 to 89% of eugenol. The second method, on the other hand, yields, strong oil, rich in eugenol (91-95% by volume).

Before distillation, the clove buds are milled and must be distilled immediately, to prevent loss of oil by evaporation.

The steam produced in a boiler is introduced into a vessel which contains the buds and water. The buds are located on a grid placed at a certain distance above the level of the water which fills the bottom of the vessel. The water is vaporized indirectly, by steam flowing in a pipe coil submerged by the water. The water vapor plus the distilled oil coming from the evaporator vessel is recovered in a separate water cooled condenser. This mixture flowing out of the condenser is separated by decantation in a Florentine flask, in which two fractions, one lighter, the other heavier, than water are separated. The two fractions must be remixed after water is decanted.

The distillate water should be redistilled to recover all the dissolved oil extracted from the clove by distillation. This process is called cohabation. Finally, the clove oil is packed and dispatched for sales.

Clove oil processing does not cause environmental pollution. The residues of buds after distillation can be dried and used as fuels and their ashes can be used as fertilizers. The water waste after being separated perfectly from the oil does not damage the environment.

Major Equipments

1. Evaporator vessels
2. Condenser (water cooled)
3. Florentine flask
4. Pumps
5. Cooling tower
6. Submersible pump
7. Boiler system Grinding unit

Bio-Oil Production Process with Flowsheet

Although the fast pyrolysis process is more accurately called thermolysis, the two terms are used interchangeably. Since 'pyro' means fire in Greek and 'thermo' means heat, thermolysis more closely describes the process, which involves heating biomass through indirect heat. The term 'fast' refers to the residence time of the biomass in the reactor. Slow pyrolysis produces more solid char, while fast pyrolysis yields more gas and liquid. The reactor design, temperature, and residence time determine the yields of the products and to some extent, their qualities.

In the fast pyrolysis process, indirect heat, followed by cooling, is used to convert biomass at 400-800°C into CO₂, CO, and CH₄ gases (medium heating value gases), Bio- Oil liquids and solid char. A flow diagram of the process is shown in figure below. The conversion of biomass to Bio-Oil occurs in the absence of oxygen in the pyrolysis reactor . Oxygen is excluded to prevent the biomass or its products from combustion.(use a N₂ gas as a fluidizing medium) Gasification is different from fast pyrolysis, or thermolysis, because it is a combustion process in which enough oxygen, through air, is supplied for the carbon and hydrogen in the fuel to form a rich mixture of CO and hydrogen in the product gas. The product gas from gasification will contain up to 60% nitrogen and have a lower heating value of 107 to 484 Btu/ft³ whereas the heating value of fast pyrolysis gases range from 484 to 807 Btu/ft³ (www.wgtuk.com/ukDefinitionGas.html).

The products exit the pyrolysis reactor in a gas state that includes vapors, aerosols, and a suspension of small solid particles. A cyclone separates most of the solid particles from the vapors, where they are then deposited to the char collector. The gases are then condensed in a quench system, which converts most of the vapor into liquid Bio-Oil. The non-condensable gases are recycled to supply the energy needed in the process, while the Bio-Oil and char can be sold as commercial products (www.DynaMotive.com/biooil).

ESSENTIAL OIL OF PEPPERMINT

Peppermint oil is extracted from the whole plant above the ground just before flowering. The plant chopped in to a size of 1-3cm, and placed on a grid which is located at a certain distance above the level of water which fills the bottom of the kettle. The water is vaporized indirectly by steam flowing in a pipe coil submerged by the water. The water and the distilled oil coming from the evaporator vessel are recovered in a separate water cooled condenser. The mixture flowing out of the condenser is separated by decantation. The distilled water, which may contain some oil, shall be sent to distillation tank in which the oil is extracted.  

The production process of peppermint oil has no impact one environment. The solid waste (straw) from steam distillation processes dried and transported to compost production or can be used as energy source. 

ESSENTIAL OILS OF ORANGE, LEMON AND LIME

It starts by chopping in small pieces the orange peel, lemon peel and lime rind respectively so that the steam can vaporize easily the essential oil in the peel or in the citrus rind.

The steam, produced in small vertical boiler is passed through steam pipes into an evaporation kettle which contains the chopped material and water. The raw materials to be processed for each type of production are located on a grid placed at certain position above the level of the water which fills the bottom of the vessel. The water is vaporized indirectly by the steam flowing through a coiled pipe covered by the water. The water plus the extracted oil coming from the evaporator is recovered in a separate water cooled condenser.

The mixture flowing out of the condenser is separated in a Florentine flask. The essential oil is collected at the top and distilled water leaves the flask at the bottom. As the water still contains some residue oil, it is sent back to the evaporator to recover the some remained oil by second distillation.

The production process is environmental friendly. The residual product of the distillation process is used for animal feed or compost production.

Ginger oil production process

Steam distillation is the preferred method for all essential oils produced in large quantity. Direct steam distillation is the most efficient method. In this method instead of making the steam in the kettle it is prepared in a boiler and then passed through the bed of ginger at a certain pressure. The steam extracts most of the essential oil and hence, this method is most economical and quick.

First of all, ginger is cut into smaller pieces with the help of a cutting machine. Usually this cutting operation is carried out manually. Manual operation is most suitable for a small scale unit. After cutting of ginger, pieces are beat with the help of a hammer to break the oil cells. Now these pieces of ginger are fed on a wire gauge, which is fixed in a mild steel kettle. After preparing the bed, the outlet of the kettle is connected to a water cooler and the outlet of the condenser is connected to the collecting pot.

The steam at is passed into the kettle from the bottom. The steam passed through the pores of the ginger bed and extracts the volatile oil with it. This extractor is carried out until hole of the volatile oil is extracted. The vapor of water and oil condenses in the condenser and falls into the collection pot. These pots are generally made of glass. In the pot, two layers are formed after the condensed vapors are settled. Water layer remains on lower side while oily layer floats on the water. Oil is separated from tin pot. Thus oil obtained by this method contains about 5 to 6% water.

For separating the ginger oil, oil water mixture is subjected to reduce pressure distillation. Crude oil is taken in a flask like kettle and some arrangement are made as stated above for distillation process. A vacuum pump is connected in series in order to create vacuum. Now the flask is heated and pump is switched on when the required temperature is reached, the vapors of oil start coming out and these vapors are collected in a pot by condensing them in a condenser.

When all the volatile oil comes out, then the temperature of the mixture in the flask starts rising and at that stage collection of vapors should be discontinued. The ginger oil is packed in 760ml. glass bottles. This packing is done manually. An air tight seal is provided to prevent the loss of oil through volatilization.

Avocado oil production process

1. Production Process

Avocado oil for industrial use consists of the following unit operations:

a) Sorting out of ripe avocado fruit

b) Washing

c) Scalding

d) Peeling

e) Pressing

f) Refining

g) Filling, packing and dispatching to market

Ripe avocado fruit harvested from farm in first properly sorted out and is prepared for processing. The damaged cenes are avoided from being processed. The sorted out fruit is then washed to remove any foreign material that might have passed from farm area to this stage. The washed avocado fruit is then dried and scalded by hot water produced by a boiler. This action further removes unwanted particles that might have possibly remained attached to the fruit.

The next operation is peeling. This is carried out by a machine, where the upper skin of the fruit is carefully removed and discharged as waste. The inner part is directly charged into a pressing machine where the oil is separated from the non-oil part. The crude oil is then refined by a refinery unit. The output of the refinery is then charged into a filling machine, where the industrial avocado oil is filled into metallic containers for final dispatch into market.

The plant has no any adverse impact on environment. The soap stock that will be generated in the refining process will be used by soap producers. The other waste that could be generated is the peel and solid waste after regeneration. This is also used for essential oil extraction and fertilizer or animal feed, respectively.

Ground oil production process

Edible oil technology can be grouped into two: mechanical pressing and solvent extraction. Sometimes the latter compliments the former. For oilseeds with high oil content such as ground nut, first mechanical pressing will be applied and over 85% of the oil will be extracted. The remaining oil in the expeller cake will then be extracted with solvent. For some other oilseed with low oil content, solvent extraction is generally considered as the best alternative. However, the initial investment cost of solvent extraction is much higher than mechanical pressing. In addition, solvent extraction is more appropriate for large scale processing than small scale edible oil plants. Therefore, in this study the mechanical pressing technology has been selected.

Ground nut oil production process, based on mechanical pressing technology, can be grouped into three stages: seed preparation, pressing and crude oil refining.

The seed requires undergoing a thorough cleaning process to remove sand, stalk, plant debris and any other foreign matters by rotary or table sieve. Usually, the screening process is assisted by air aspiration unit. After cleaning, the seeds have to be prepared for efficient oil recovery by pressing. The stages involved are size reduction of the seeds by breaking them and then conditioning the seeds by adjusting their moisture content and temperature, while keeping the seeds hot (say 90-95ºc) for a period of 30-60 minute. Then the prepared seed shall be conveyed to the screw pressing machine where it is pressed by the action of worm and outer shell. The crude oil so obtained from the pressing will be first clarified in a settling tank and then shall be pumped through the filter press.

The filtered crude ground nut oil will be pumped to the refinery where it shall pass through three stages of refining: neutralization, bleaching and deodorization.

To reduce the level of free fatty acid (FFA) in the oil, caustic soda will be mixed with the crude oil. The neutralized oil may have trace of soap which is a by-product of the neutralization process. Therefore, the oil will be washed with water. It will then be pumped to the bleacher in which it will be mixed with bleaching earth to improve the color of oil by the process called adsorption. The bleached oil, after being filtered, will be pumped to the deodorizer to avoid substances which are responsible for the odor of edible oil. In some very small plant the three stages of refining crude oil shall be executed in a single vessel. The plant requires a containment vessel for the collection and treatment of wastes to be generated in the process.

Vegetable oil and fats production process

Process description


Details of vegetable oil business here

There are two extraction technologies, one is mechanical pressing and the other is solvent extraction. The most important factor in the choice of the processing plant, and the processing sequence, is the seed to be extracted, its yield, capacity and the quality of products to be achieved. The minimum capacity recommended for solvent extraction process is 150-200 t /day feed stock. In addition to the above restriction, mechanical presses has the advantage of reduced capital cost, no danger of fire from combustible solvent, simpler process control and smaller number of skilled staff over solvent extraction process. 

The seed requires a thorough cleaning process to remove sand, stalk, plant debris and any foreign matters by rotary or table sieves, usually with air aspiration by fans, and cyclones for dust removal from the air. Then, the seed have to be prepared for efficient oil recovery. The stages involved in pre-treatment are:

a) Size reduction of the seeds by breaking them, usually in fluted roller mills;

b) Flaking of the seed particles in roller mills with smooth roller surfaces (0.2 -0.3 mm);

c) Conditioning the seed by adjusting their moisture content and temperature, while keeping the seed hot (say 90-95⁰C) for periods that vary widely (30-60 minutes). Then, extraction by using high pressure screw press follows.

The crude oil obtained from the press requires undergoing refining processes to produce a bland tasting, light coloured oil without odour or flavour. To obtain fully refined oil from crude oil, the following steps are necessary: degumming, neutralizing, bleaching,

Winterizing and deodorizing. The refined oil is, then, packed and marketed. The refined oil containing unsaturated fatty glycerides are by partial hydrogenation rendered into fats of more suitable composition for edible purposes. The hydrogenation process consist of the following two process steps; hydrogenation and post hydrogenation refining stages (the refining process mentioned above)

Source: Shreves, Chemical process Industries

Vegetable oil production process video

The main waste material from oil manufacture is water and much attention should be given to the water treatment to avoid its adverse effect in the environment. Biological treatment by aerating, activated sludge system, addition of flocculating agent and filtration are used before the effluent is discharged.

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