Base oil production process consists of two stages. First stage is Pre-distillation by Atmospheric Pressure method, second stage is separation to the fractions by Vacuum Distillation method.
The purpose of the first stage is to remove the products in the oil which have low boiling points and the water if there is.
The products having low flashing points are separated at this stage, because this is also the stage that the change is prepared to vacuum column. Therefore, this minimizes the operation stage which is necessary for flashing at the vacuum distillation. (In fact according to the raw products ingredient, flash value might be retracted to the intended grade).
Second stage is the separating to fractions by using the vacuum distillation method. In this stage three products and one deep residuum are obtained.
The product that exits from the top is named as ‘Lt. Oil’. The product obtained from one-down of the top is named as ‘Md. Oil’. The product obtained from the one-top of deep is named as ‘Hv. Oil’.
- Pre-Distillation (under atmosphere pressure)
- Vacuum Distillation (separation to fraction under vacuum)
- Tanks and tank range
- Filtering system
- Cooling tower and systems
- Air and air systems
- Flare and vacuum systems
- Tanks are the equipments that products of the plant which will be changed, sealed, and removed are stored. A plant has pre-distillation and capacity of 300 ton/day, there has to be manufactured at least 7 X 300 ton and 3 X 300 ton capacity tanks. We can classify these tanks as below;
Three clean product tank, one as deep residuum tank, the other is pre-distillation top residuum tank and the third is processed charge tank.
- Filtration system: the clean produced product tanks has circulation inside by passing from this filtration system.
- Cooling Tower: these towers are available at every refineryand are manufactured to cool the products produced in the system and required to send to the tanks and they provide to cool the water that arrives to the coolers and to circulate in the system.
- Air system: generally the control systems installed for the plant are working with air. Due to this reason, an air compressor has to be provided to the plant.
- The undesirable gases generated during the production process will be also removed. The gases will be burned at flare to prevent them to damage the environment. Flare is the oven that these gases are burned.
- There will be need for a continuous power source cause the plant has been designed it will work 24 hours a day. If city electric is used, there has to be installed a generator back up the electricity system. If there is no city electric, there has to be installed 2 generators.
- Vacuum is not applied at pre-distillation stage.
- Heating and vacuuming is never applied before the product is taken into the system.
- It is not definite which product will be obtained at which temperature without knowing the properties of the charge which will be taken into the unit but approximate value can be given only for the products that has certain boiling ranges.