SOLVENT EXTRACTION
Andreotti Impianti technologies cover all the necessary equipment for oil solvent extraction from oil seeds flakes or pre-pressed cake, as well as the machinery dedicated to desolventized meal treatment.
Apart from the type of extraction process used, that depends from the nature of raw material to be processed, each plant is designed for optimizing the process parameters and for reaching the best quality results with the lowest possible consumption and in conformity with the latest pollution prevention rules.
The typical extraction process is composed of 4 main steps:
- Extraction by solvent of the oil from the oilseed, which gives out two products: Miscella oil-solvent, meal wetted with solvent
- Separation of the oil -solvent miscella
- Recovery of the solvent from the meal
- Adsorption of carburated airs
SOLVENT EXTRACTION SECTIONThe seed after relevant preparation in the pre-treatment plant (cleaning, de-hulling, cracking, cooking, flaking and pressing) feeds the extractor where it is laid on a filtering belt with automatic level control devices. The filtering belt moving from one to the other side of the extractor charges the oil cake coming from the feeding hopper, submits the seed cake to solvent shower and discharges the de-oiled cake into the extractor discharging hopper from which the same by screw conveyor and chain elevator goes
to the next step.
The solvent (Hexane) enters the extractor in the opposite side of the oilseed, it is sprayed on the seed belt, flows through the same and is recovered in the underneath hopper from where it is pumped into the next sprayer step; the number of sprayer steps changes depending on the capacity of the plant. The solvent with extracted oil is pumped to the next step. Solvent is enriched with oil, as it goes through the different steps.
Andreotti Impianti can propose different types of Extractor Equipment : Belt Extractor ( B-Type) or Rotary Extractor ( R-Type), the choice of which depends on specific applications beside the targeted plant capacity.
DISTILLATION SECTION
The oil-hexane miscella from relevant tank is pumped to the distillation section where the hexane is distilled under vacuum and subsequently stripped from the oil with live steam. Thanks to the use of specific process solutions, as for example particular distillation strippers, dedicated economizers and special designed air condensers , is possible to reach a very high process parameters optimization:
- residual hexane content in the oil :< 40 ppm
- reduction of steam consumption : 35%
- reduction of water consumption : 70%
The meal with solvent leaving the extractor feeds the upper layer of the toaster, where all the hexane is distilled from the meal by heating with indirect steam, by stripping by live steam and by mixing with a shaft. The meal is dried with hot air and cooled with cold air in the bottom layers of the machine.
The vapours together with the live steam are re-used ad heating fluid in the economizers and then are condensed for being sprayed again onto the meal in the top of desolventizer.
The level in D.T.D.C is maintained automatically with electronic level control and variable speed rotary valve in order to avoid any by pass of product / vapour. If required, between the lower desolventizer layer and the drying section is inserted a new layer that is maintained at the desired (de)pressure and the outgoing vapours are condensed and recycled to the system. Some advantages:
- Full water recycling
- Reduction of steam consumption
- Increasing of desolventizing efficiency
- Reduction of hexane losses
ABSORPTION OF CARBURATED AIRS
Thanks to patented designing solutions, the Andreotti Impianti's adsorption plant efficiency can be increased up to 99,6% (value calculated from lab analysis on effluents). Among the others:
The adsorption column works under pressure , instead of de-pressure, and it's regulated with safety valve with a consequent shifting of the gas/liquid equilibrium of Hexane by the effect of the pressure to liquid.
A particular configuration of heat exchangers let possible to reach a heat recovery up to 65% and to reduce proportionally steam and cooling consumptions.
ZERO EFFLUENT SYSTEM
Water effluent = 0 kg/ton
Waste water = 0 C.O.D
NO LIQUID EFFLUENT
Andreotti Impianti's environmental friendly technology approach led to the development of a new system to eliminate liquid effluents, which transforms, trough an evaporation system, the slightly polluted water from solvent extraction into live steam which is used in DTDC for meal desolventizing.
LOW EMISSION
On air disposal, the innovative Andreotti Impianti's system reduces the hexane content in the air emission to a minimum low level. The air is washed in counter current with mineral oil in a special pressure column, where the hexane is absorbed. The system works in a closed circuit and the hexane absorbed is evaporated and recycled.
FULL AUTOMATION
Each plant designed by Andreotti Impianti is equipped with the latest version of a specific control automation and supervision system. Among the main advantages of our fully automatic solutions, we could list:
- Remote process management
- Fully automatic start & stop procedures
- High safety level
- Reduction of fire & explosion risk
- Just in time process overview
- Just in time main parameters analysis
- Just in time figure's contol
- Reduction of operator interaction
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