Studies On The Process Of Adsorption Deacidification And Its Adsorbents Of Vegetable Oil

In order to meet both the needs of the energy saving and environmental protection in the oil and fat processing industry, as well as to meet the constantly increasing demands of the quality of edible oil, oil refining technology must be constantly updated. Considering the problems existing in traditional methods, the activated Ca-sorbent which have the capacity of adsorb free fatty acid was studied in this paper. The method of adsorptive deacidification can reduce the loss of neutral oil, and avoid the formation of trans fatty acids and save water.The activated Ca-sorbent must be prepared by adding water, the amount of calcium oxide and water usage have significant influence on the deacidification ability of the activated Ca-sorbent. The optimum conditions to make activated Ca-sorbent was: 50% calcium oxide, water usage 1ml/g, the processing time 16h, processing temperature 60℃. The deacidification ability of activated Ca-sorbent was mainly determined by the content of Ca(OH)+ in interlayer, the higher content of Ca(OH)+, the stronger deacidification ability. The deacidification ability of activity Ca-sorbent was not only created from its porous structure but also from its well physical adsorption, which produced from its huge specific surface area, the most important factor was the chemical bonding adsorption produced between the inter-layer OH- and the organic compounds molecules.The activated Ca-sorbent is unstable in acid solution (pH<2), the Ca(OH)+ is more easily to diffused from layers with the stronger acidity solution. The activated Ca-sorbent is also unstable at a higher temperature (200 ~ 300℃) , its interlayers water has been removed, the effect of adsorption decreased significantly but still has a certain capacity of deacidification. When the temperature reached 350℃, the lamellar structure of activated Ca-sorbent was collapsed and completely losted its deacidification ability. Therefore, the processing temperature must not exceed 150℃in the adsorption process.The application of the activated Ca-sorbent in oil refining was explored in this paper. The results show that: the saturation point of adsorption was 312.5mg/g, so we can known that activated Ca-sorbent is a very good adsorbent of free fatty acids; In the absorption process, the stirring speed and the amount of activated Ca-sorbent have significant influence on deacidification effect. The optimun conditions of adsorption deacidification was: the amount of activated Ca-sorbent 5% and the stirring speed 180r/min, the adsorption temperature 50℃; Activated Ca-sorbent was applied in the low temperature refining process of rapeseed crude oil, the satisfactory results and good product were taken by use of decolorization - deacidification technology.The loss of neutral oil was 0.64% for each one percent lower of FFA In the adsorption deacidification technology, was be half of the neutral oil loss in traditional alkali refining Deacidification. The waste Ca-sorbent contained about 66% fatty acid calcium and can be an excellent feed additive.