Chapter 9 - Handling, Storage, and Transport of Crude and Crude Degummed Soybean Oil

Abstract

An important criterion in handling, storage, and transport of crude soybean oil is degumming. In the presence of moisture, the phosphatides in non-degummed oil hydrate and precipitate as sludge. To avoid this problem, oil for export or long-term storage is degummed. Water degumming removes the major part of the phosphatides, which may be recovered as lecithin or returned to the meal. Non-degummed crude soybean oil is commonly utilized by U.S. refiners. This is feasible because the oil is usually stored for relatively short periods. Deterioration of crude soybean oil is promoted by moisture, impurities such as meal fines, high temperatures, exposure to air, and contact with copper or other metals that promote oxidation. Therefore, crude oil to be degummed for lecithin production should be filtered and this is best done when the oil is fresh. Lecithin that is perfectly clear commands a premium price, but the centrifugal separation of lecithin concentrates fines while removing some fines from the oil. Degummed oil is dried in a vacuum dryer after degumming and should not exceed 0.1% moisture. Storage tanks of soybean oil at extraction plants, or terminals, are cylindrical and of mild steel construction. This chapter further discusses the overland transport and water transportation of soybean oil. A major concern in handling and transporting vegetable oils is to avoid contamination. In particular, substances regulated by pure food laws must be in conformance with established limits, but other substances also need to be controlled. Trading rules include various regulations on cleaning, inspection, and separation practices in transport equipment.