Vacuum is necessary during various steps of vegetable
oil processing. These steps essentially include hydrogenation, fractionation, bleaching, deodorization and de-acidification.
Out of all vacuum equipments, Ejector Vacuum System has established the superiority and versatility of their use as compared to the mechanical vacuum pump.
The most outstanding advantage of the Steam Jet Ejector is the total absence of moving parts, which eliminate mechanical breakdown, and assures constant and dependable operation with freedom from repairs.
No adjustment or lubrication is required nor are any specially trained operators necessary as their operation is very simple.
Over and above this, as Steam Jet Vacuum System convey at very high velocity which are many times the speed of sound, they are capable of handling large volume under vacuum thus making them eminently suitable for deodorization application wherein high quantity of open / sparging steam has to be handled.
A Steam Jet Ejector is simplified type of vacuum pump or compressor, consisting of three basic parts :
1. Nozzle
2. Mixing chamber
3. Diffuser
The Nozzle discharges a high velocity Steam Ejector across a suction chamber that is connected to the equipment to be evacuated. The process vapours are entrained by this Steam Jet and carry into a Venturi shape diffuser, which convert the velocity energy of the steam into pressure energy enabling discharge ultimately to atmosphere.
The Nozzle discharges a high velocity Steam Ejector across a suction chamber that is connected to the equipment to be evacuated. The process vapours are entrained by this Steam Jet and carry into a Venturi shape diffuser, which convert the velocity energy of the steam into pressure energy enabling discharge ultimately to atmosphere.
The Ejectors are generally categorized into one of four types:
1. Single Stage.
2. Multi-stage condensing.
3. Multi-stage non-condensing.
4. Multi-stage with both condensing and non-condensing stages.
Lower suction pressure is obtained by staging of the Ejectors. The number of stages of Ejectors is depended on the suction pressure required. Nominal range of suction pressure for number of Ejector is stated below:
|
Stages |
Nominal range of pressure (in torr) |
Nominal range of Vacuum (in mm Hg (v) |
|---|---|---|
| Single stage | 80 – 300 torr | 460 – 680 mm Hg (v) |
| Second stage | 12 – 100 torr | 660 – 748 mm Hg (v) |
| Third stage | 4 – 25 torr | 735 – 756 mm Hg (v) |
| Fourth stage | 4 – 0.06 torr | 756 – 759.4 mm Hg (v) |
| Fifth stage | 0.6 – 0.02 torr | 759.4 – 759.98 mm Hg (v) |
| Sixth stage | 0.05 – 0.01 torr | 759.95 to 759.99 mm Hg (v) |
|
Motive Pressure |
Discharge Pressure |
Suction Pressure |
Suction Capacity |
|---|---|---|---|
| Decrease | Constant | Increase rapidly | Decrease rapidly |
| Constant | Increase | Increase rapidly | Decrease rapidly |
| Constant | Constant | Increase | Increase |
| Constant | Constant | Decrease | Decrease |
| Increase | Constant | Constant | Decrease rapidly |
| Constant | Decrease | Constant | Unchanged |
Also, nowadays, considering high cost of energy, mainly steam, most of the installations have incorporated multiple nozzle Boosters which consume about 15 20% lesser steam compared to conventional single nozzle Booster designed for the same motive and suction pressure and capacity.
Mazda Limited in India supplies these special multiple nozzle Boosters since last ten years in collaboration with world leaders
Mazda can therefore, claim to be instrumental in improving the efficiency of various refineries and saving India’s precious natural resources.
