The primary purpose of oil storage terminals is to facilitate the 

 rapid loading and unloading of tankers. There are two primary reasons 

 that rapid oil transfer is desirable: (1) economic, and (2) logistic. 

 First, tanker "downtime" during unloading is costly. The faster the 

 tanker can unload and return for more oil, the greater will be its 

 profit. Secondly, since stormy weather can often interrupt oil transfer 

 operations, the faster that oil can be transferred, the shorter the good 

 weather period required, and the fewer the chances for weather caused 

 interruptions. 



Description 



An oil storage terminal consists of numerous large cylindrical 

 steel storage tanks, oil -pumping and coolant-water equipment, inter- 

 connecting pipelines, an administration and control building, and large 

 diameter crude-oil pipelines. A typical storage terminal handles a 

 volume of one million barrels of oil per day (Figure 37). 



Surrounding an oil storage terminal, as well as each of its individual 

 tanks, is an earth or concrete dike. The dike excludes floodwaters and, 

 in the event of a tank rupture, retains the oil within its boundaries. 

 These dikes also facilitate the collection and the treatment of storm 

 water runoff to remove oil contamination. 



Oil storage terminals also include several water collection and 

 treatment systems. A small sewage treatment system is included to 

 handle domestic sewage. A storm water collection system collects and 

 discharges unpolluted storm water runoff. A third system is used to 

 collect runoff plus water from processing that has come in contact with 

 or is polluted with oil. Oil separation facilities and aeration ponds 

 clean up these waters prior to discharge. These oil treatment facilities 

 can be of considerable size if oil ballast water is discharged at the 

 terminal, as it will be at an oil transfer terminal geared to oil export 

 via tankers. 



Oil storage terminals also have fire-fighting facilities. A pond 

 providing water to extinguish fires will be constructed onsite if the 

 terminal is not adjacent to water. A fire station with several pump 

 trucks is required. 



The steel tanks at an onshore oil storage terminal can be of two 

 types--fixed roof or floating roof. Each time a fixed roof tank is 

 filled, the hydrocarbon vapor in the void of the tank is displaced and, 

 therefore, discharged to the atmosphere. A floating roof tank eliminates 

 this problem and greatly reduces emissions because it moves up and down 

 on the oil's surface accommodating only the volume of oil within the 

 tank. 



169 



