API BULL 2516-1962
Evaporation Loss from Low-Pressure Tanks
- Standard No.
- API BULL 2516-1962
- Release Date
- 1962
- Published By
- API - American Petroleum Institute
- Latest
- API BULL 2516-1962
- Scope
- Introduction The term low-pressure tank@ as used in this evaporation loss bulletin@ refers to vessels having a maximum pressure vent setting in the range from just above atmospheric pressure to 15 psig and a vacuum vent setting normally 1 to 2 oz per sq in. The tanks are used for the storage of products@ such as motor gasoline@ pentanes@ and natural gasolines@ having a Reid vapor pressure up to 30 lb. Although a storage pressure of less than 2.5 psig may be used for some products@ the type of vessel construction does not permit appreciable economy by using lower design pressures. The loss principles applying to 2.5-psig to 15-psig pressure will also apply for higher or lower working pressures than the specified range. Low-pressure tanks are constructed in many sizes and shapes@ depending upon the operating pressure range. Fig. 1@ 2@ 3@ and 4 show typical types of construction. Pressure tanks differ from other conservation tanks in that they have neither moving parts nor a variable vapor space. The principle of operation is the same as that for the conservation vented fixed-roof tank. The basic difference is the ability of low-pressure tanks to withstand higher pressure variations. Because of this@ venting loss due to boiling and breathing loss due to daily temperature changes are prevented. By increasing the tank design pressure@ liquids of higher volatility may be stored without breathing loss. The Amount of loss from pressure storage tanks has been considered by users and tank manufacturers@ but few data are available. Therefore@ a theoretical basis has been used to estimate losses resulting from various storage conditions and types of products. Four types of losses are considered: breathing loss@ boiling loss@ working loss@ and leakage loss. Factors are discussed that affect the performance of low-pressure tank storage.
API BULL 2516-1962 history
- 1962 API BULL 2516-1962 Evaporation Loss from Low-Pressure Tanks
