Deodorization Process.

Deodorization is the last major processing step in the refining of edible oils. It has the responsibility for removing both the undesirable ingredients occurring in natural fats and oils and those which may be imparted by prior unit processes such as caustic refining, bleaching, hydrogenation, or even storage conditions. It is this unit process that finally establishes the oil characteristics of "flavor and odor," which are those most readily recognized by the consumer when the shortening, lard, salad oil, cooking oils and margarine are usedExperience has shown that flavor and odor removal correlates well with the reduction in free fatty acid (FFA) content of the oil. If oil has an FFA of 0.1%, it will have an odor that will be eliminated when the FFA is reduced to 0.01 to 0.03% assuming a zero peroxide value (Imai, C.H et. al., 1974). Thus, this shows clearly the function of deodorization is to lower down the FFA content in palm oil.Deodorization is a vacuum steam distillation process that uses steam under reduced pressure. Thus, it shows that pressure and temperature are the main variables that should be controlled without failure to prevent loss of quality in end products. Pressure and temperature has equal importance for this process. But, after consideration of the usage of pressure has coherent role, this project reports on the study of pressure equipment.

Imai, C.H., Watanabe, N. Haga, and T. Li, Ibid. 51:495 (1974).

Experimental Procedure for Deodorization

Palm oil that is ready for the end user use has to undergo three processes that is, refining process, bleaching and finally deodorization. So, after the oil has undergone degummed and bleached process, the oil is then will be prepared to deodorization process. Start vacuum system V08I at the control panel and evacuate deodorizer D08I to a pressure (vacuum) of about 6.7 mbar.

Start pump - P704 and feed oil from the storage tank to deodorizer D08I. As it reached high level of HLA08I, stop pump P704. Switch on electrical heating element HT08I. Set the deodorization temperature .

Start vacuum system V08I at the control panel and evacuate deodorizer D08I to a pressure (vacuum) of about 6.7 mbar.

Use the metering valve to set the flowrate of sparging steam to deodorizer D08I. Maintain the oil in deodorizer D08I at the deodorization temperature and pressure under steam sparging for the desired deodorization time.

At the end of the deodorization time, switch off electrical heating element and stop temperature controller TIC08I.For cooling process, start cooling water flow to the internal cooling to less than 90C.

Open the vent valve of deodorizer D08I to break the vacuum. Start pump P08I and discharge the oil to storage tank T082 through polishing filter F08.

When deodorizer D08I is empty, stop pump P08I. Empty the pipelines by opening the drain valve at the pump.

Pressure use in the Deodorizing unit.

The vacuum in the deodorizer is usually created by a combination of steam ejectors (boosters), vapor condensers and mechanical (liquid-ring) vacuum pumps. These quite robust systems typically reach pressures in the deodorizer between 2.5 and 5 mbar. In the deodorizing unit, the oil that will be deodorized should maintain a constant temperature and vacuum pressure for the whole time of deodorizing time. Thus, to maintain this pressure and temperature, monitoring the equipment for a constant flow is crucially needed. This is where instrumentations plays a major role in maintaining a smooth flow without lack. To produce a high quality and highly refined palm oil, the parameters shown below is as suggested by Arnold M. Gavin (1998).Table 1: Deodorization parameters as suggested by Arnold (1998)ParametersDeodorization (Range)

Temperature (oC)220-260

Pressure (mmHg)5-20

Contact time (minutes)30-60

Pressure Gauge used in the Deodorizing unit.