Steam distillation is utilized in extracting essential oils at temperatures near to 100℃, followed by subsequent condensation to form an liquid from which the essential oil can be separated in a clarifier.
Steam or water is added to the distillation apparatus, lowering the boiling points of the compounds. The goal is to heat and separate the components at temperatures below their decomposition point.
Steam distillation is the preferred method used to isolate most essential oils. It is also used for stripping in petroleum refineries and to separate commercially important organic compounds, such as fatty acids.
Some essential oil herbs and plants such as calendula, sage and rose oil require solvent based extraction, for more information have a look at our Solvent Distillation range
The Retort or BioStill is a pot or vessel which is filled with essential oils bearing plant matter and sealed airtight.
Super heated steam is blown through a specially designed in let to defuse the steam equally through the retort. Once the temperature in the retort reaches over 100℃ the volatile oils also composing of terpenes are evaporated off the plant matter. The steam vapour moves into the condenser which condensers the vapour into water and oil phases. The 'rich steam' is virgin steam from the steam generator binding to the essential oils in the plant matter. The steam enters the condenser at about 130℃
Steam generation is expensive and releases CO2 into the atmosphere. It is widely believed to cause global warming. BioAfrica researched the most efficient method using biomass like leaves and distilled plant matter as fuel for the boilers and steam-generating. The plant matter burned for this years steam; regrows next year and is almost carbon neutral.
The steam generators are built from Stainless steel to minimize scale and build up of lime and magnesium deposits on the inside of the steam-generators.
BioAfrica sticks to the Safety regulations Law, each steam generator is weld tested, pressure tested, and certified where required.
Some countries and clients prefer to utilize their spent plant matter for compost and soil fertility and use natural gas. Gas burners are available in all models of steam generators and Boilers.
Steam generator are not measured by volume of water in vessel but in KG steam they deliver at a certain pressure.
The condenser is several pipes that converts steam in a gaseous state to liquid in form of water and essential oils. This is done by circulating cold water past a number of pipes containing the hot rich steam. The capacity of the condenser is measured by the amount of steam converted to liquid per hour.
The condenser is usually accompanied with a water cooler which recycles the water through the condenser. The condenser cools water about 20℃, entering the condenser flows past the pipes containing rich steam, as the the steam condenses to liquid it releases energy to the water heating the water above to above 45℃.
The water cooler pumps about 4000 litres per hour through the condenser. The water is recycled and cooled in the water cooler. Water is scarce in Africa and we need to save it and Recycle.
The water or Hydrolyte and essential oils mix fall into the inlet funnel of the separator. The less dense oil rises above the water is split from the essential oils. The Hydrolyte is fed back into the Boiler, this increases the oil yield.
The BioStill retort is measured in metric litres, about 1 cubic meter of volume of plant matter is roughly 200-400 kg in weight. The steam is expensive to generate so to prevent any additional loss all BioStills are fully insulated and covered or clad with aluminium to keep the insulation in place. The Retort is mounted on an A-shape frame to allow it to swivel making it easy to load and discharge the spent plant matter. The lid is not insulated and fastened with high tensile bolts. The seal is oil, heat and movement resistant. The retort has 3 openings. At the bottom of each retort there is a quick coupling to fasten the steam pipe this allows the steam to move evenly through the plant matter.
An automatic float valve to maintain a contain water level
A sight glass that allows humans to see the safe operating level
A blow down valve to discharge any sand, lime and impurities
A flexible rubber steam grade hose to deliver the steam to the retort or distillation pot
All BioSteam devices are sold with a water pre heater in the firebox to preheat water thus not cooling the boilers down with cold water