Solvent distillation is carried out in three stages of vacuum to achieve an incremental concentration of miscella at a predetermined rate. Each stage is differentiated by the incorporation of a precisely designed U type siphon pipe, eliminating the use of a centrifugal pump to ensure a continuous flow of miscella and reduce power consumption. The Economizer is a compact design with a built-in flasher and requires minimum floor space and less piping. It provides high-efficiency flashing, which increases the miscella concentration up to 75%.
Final stage stripping is carried out in the presence of steam under a higher vacuum of 700 mmHg, allowing lower temperature distillation and ensuring undamaged crude oil without colour fixation. Maximum solvent from the oil–solvent mixture (miscella) is recovered at the distillation stage. Final solvent traces from oil coming out from distillation zone are recovered in oil stripper working under vacuum. Air entrapped within the system along with solvent is passed through the recuperation system where solvent traces from outgoing vent gases/vapours are recovered by absorbing the solvent in mineral oil. Hexane from the solvent absorbent is recovered by heating the mixture and condensing the solvent. This solvent-free absorbent oil is reused for recuperation/recirculation.
- Highly efficient cyclone-centrifugal separator type fines separation system helps to avoid fouling in the distillation system and minimizes over-heating of the oil, reducing utility consumption.
- Lower retention, maximum heat transfer takes place which enhances oil quality.
- Stripper is designed for proper film formation and removal of solvent.
- Dryer is designed for high vacuum and comes with a spraying system to remove traces of hexane and dry the oil before discharge.
- Hydroclones are used to separate fines from the miscella before entering to the distillation section.
- Lower deposition of sludge in the evaporators’ tubes minimizes frequent cleaning.
- Condensers are designed for optimum solvent condensation at reduced vacuum at a wide range of cooling water temperatures.
- Vapour absorption system with well-calculated packing area and stripping section to absorb uncondensed hexane before escaping to the atmosphere preventing solvent loss.
- Less effluent discharge.