The MultistockTM is a single shell compact column containing several integrated trays or compartments.
In the upper part of the MultistockTM the oil is heated to deodorising temperature and then cooled in the lower part of the MultistockTM
Thermosyphon heat exchange
This is accomplished with the thermosyphon heat recovery system in which the hot oil after deodorization is used to generate steam, which is condensed in the top tray to heat the incoming bleached oil.
In the second tray the oil is heated to deodorization temperature with high pressure steam.
In the deodorizing trays the oil remains as a batch in the tray and movement must be induced.
This is done by introducing the stripping steam into the tray in a number of gas-lift pumps.
Optimum contact area
The high capacity pumping action produced results in rapid circulation of the oil in the tray. The oil at the bottom of the tray is moved to the optimum contact area at the surface many times during the process cycle.
A large surface area between oil and steam is ensured by the initimate contact within the gas-lift pumps and also by the generation of a thin film at the discharge of each pump.
With this steam injection system, a deeper oil layer improves the circulation rate of the pumps.
Therefore, the overall diameter of the MultistockTM may be kept within reasonable limits.
After initial cooling in the thermosyphon system, the deodorized oil may be cooled to discharge temperature in a number of ways with the possibility of obtaining some extra heat recovery:
- Generation of a constant supply of hot water,
- Generation of low pressure steam
- A second thermosyphon to heat incoming oil
- Using water from the cooling tower
The MultistockTM is designed for the factory requiring maximum flexibility in processing different feedstocks daily. Product change is totally automated with the possibility of no production loss and minimum interstock contamination. The MultistockTM vessel mechanical design and process operating data covering normal operation, start-up and shut-down conditions have been submitted to rigorous finite element analysis for possible metal fatigue problems due to the thermal cycles (400.000 cycles over 20 years operation). The highest stressed areas are strengthened and welding specifications guarantee a long working life.
MultistockTM major points
Frequent stock changes : up to 40/ day
Adaptable batch size : flexibility
Proven and calculated reliability
Low contamination : product purity
Ideal coil design
Excellent vapour scrubbing
