Table of Contents 7.1 Organic Liquid Storage Tanks ............................................................................................................... 3 7.1.1 General ............................................................................................................................................ 3 7.1.1.1 Scope ........................................................................................................................................ 3 7.1.1.2 Process Description .................................................................................................................. 4 7.1.2 Emission Mechanisms And Control ............................................................................................... 8 7.1.2.1 Fixed Roof Tanks ..................................................................................................................... 8 7.1.2.2 Floating Roof Tanks................................................................................................................. 9 7.1.3 Emission Estimation Procedures ................................................................................................... 14 7.1.3.1 Routine Losses From Fixed Roof Tanks ................................................................................ 16 7.1.3.2 Routine Losses From Floating Roof Tanks ........................................................................... 31 7.1.3.3 Floating Roof Landing Losses ............................................................................................... 38 7.1.3.4 Tank Cleaning Emissions ....................................................................................................... 38 7.1.3.5 Flashing Loss ......................................................................................................................... 56 7.1.3.6 Variable Vapor Space Tanks .................................................................................................. 56 7.1.3.7 Pressure Tanks ....................................................................................................................... 57 7.1.3.8 Variations Of Emission Estimation Procedures ..................................................................... 58 7.1.4 Speciation Methodology ............................................................................................................... 63 Figure 7.1-1. Typical fixed-roof tank .......................................................................................................... 67 Figure 7.1-2. External floating roof tank (pontoon type) ............................................................................ 68 Figure 7.1-3. External floating roof tank (double deck) ............................................................................. 69 Figure 7.1-4. Internal floating roof tank ..................................................................................................... 70 Figure 7.1-5. Domed external floating roof tank ........................................................................................ 71 Figure 7.1-6. Vapor-mounted primary seals ............................................................................................... 72 Figure 7.1-7. Liquid-mounted and mechanical shoe primary seals ............................................................ 73 Figure 7.1-8. Secondary rim seals ............................................................................................................... 74 Figure 7.1-9. Deck fittings for floating roof tanks ...................................................................................... 75 Figure 7.1-10. Deck fittings for floating roof tanks .................................................................................... 76 Figure 7.1-11. Slotted and unslotted guidepoles ......................................................................................... 77 Figure 7.1-12. Ladder well .......................................................................................................................... 78 Figure 7.1-13a. True vapor pressure of crude oils with a Reid vapor pressure of 2 to 15 pounds per square inch ............................................................................................................... 79 Figure 7.1-13a. True vapor pressure of crude oils with a Reid vapor pressure of 2 to 15 pounds per square inch .............................................................................................................................................................. 79 Figure 7.1-14a. True vapor pressure of refined petroleum stocks with a Reid vapor pressure of 1 to 20 pounds per square inch ................................................................................................................................ 80 Figure 7.1-13b. Equation for true vapor pressure of crude oils with a Reid vapor pressure of 2 to 15 pounds per square inch ................................................................................................................................ 82 Figure 7.1-14b. Equation for true vapor pressure of refined petroleum stocks with a Reid vapor pressure of 1 to 20 pounds per square inch ............................................................................................................... 82 Figure 7.1-15. Equations to determine vapor pressure constants A and B for refined ............................... 82 Figure 7.1-16. Equations to determine vapor pressure Constants A and B for crude oil stocks ................. 83 Figure 7.1-17. Equations for the average daily maximum and minimum liquid surface temperatures ...... 83 Figure 7.1-18. Reserved. ............................................................................................................................. 84 Figure 7.1-19. Vapor pressure function ...................................................................................................... 85 Figure 7.1-20. Bottom conditions for landing loss ..................................................................................... 86 Figure 7.1-21. Ladder-slotted guidepole combination with ladder sleeve .................................................. 86 Figure 7.1-22. Slotted-guidepole with flexible enclosure ........................................................................... 87 06/2020 Liquid Storage Tanks 7.1-1 Table 7.1-1. LIST OF ABBREVIATIONS USED IN THE TANK EQUATIONS ............................... 90 Table 7.1-2. PROPERTIES (MV, ML, PVA, WL) OF SELECTED PETROLEUM LIQUIDS ................ 92 Table 7.1-3. PHYSICAL PROPERTIES OF SELECTED PETROCHEMICALS ................................ 93 Table 7.1-4. Height of the Liquid Heel and vapor space under a landed floating roof ........................ 100 Table 7.1-5. LEL VALUES FOR SELECTED COMPOUNDS .......................................................... 101 Table 7.1-6. PAINT SOLAR ABSORPTANCE .................................................................................. 102 Table 7.1-7. METEOROLOGICAL DATA (TAX, TAN, V, I, PA) FOR SELECTED U.S. LOCATIONS .............................................................................................................................................................. 103 Table 7.1-8. RIM-SEAL LOSS FACTORS, KRa, KRb, and n, FOR FLOATING ROOF TANKS ...... 140 Table 7.1-9. RESERVED ..................................................................................................................... 141 Table 7.1-10. AVERAGE CLINGAGE FACTORS, CS ....................................................................... 142 Table 7.1-11. TYPICAL NUMBER OF COLUMNS AS A FUNCTION OF TANK DIAMETER FOR INTERNAL FLOATING ROOF TANKS WITH COLUMN- SUPPORTED FIXED ROOFS .......... 142 Table 7.1-12. DECK-FITTING LOSS FACTORS, KFa, KFb, AND m, AND TYPICAL NUMBER OF DECK FITTINGS, NF ........................................................................................................................... 143 Table 7.1-13. EXTERNAL FLOATING ROOF TANKS: TYPICAL NUMBER OF VACUUM BREAKERS, Nvb, AND DECK DRAINS, Nd ...................................................................................... 146 Table 7.1-14. EXTERNAL FLOATING ROOF TANKS: TYPICAL NUMBER OF ROOF LEGS, Nl .............................................................................................................................................................. 147 Table 7.1-15. INTERNAL FLOATING ROOF TANKS: TYPICAL NUMBER OF DECK LEGS, N1, AND STUB DRAINS, Nd ..................................................................................................................... 148 Table 7.1-16. DECK SEAM LENGTH FACTORS (SD) FOR TYPICAL DECK CONSTRUCTIONS FOR INTERNAL FLOATING ROOF TANKS ................................................................................... 148 Table 7.1-17. ROOF LANDING LOSSES FOR INTERNAL OR DOMED EXTERNAL FLOATING ROOF TANK WITH A LIQUID HEEL ............................................................................................... 149 Table 7.1-18. ROOF LANDING LOSSES FOR EXTERNAL FLOATING ROOF TANK WITH A LIQUID HEEL...................................................................................................................................... 149 Table 7.1-19. ROOF LANDING LOSSES FOR ALL DRAIN-DRY TANKS .................................... 151 Table 7.1-20. TANK CLEANING EQUATIONS – VAPOR SPACE PURGE EMISSIONS ............. 152 Table 7.1-21. TANK CLEANING EQUATIONS – CONTINUED FORCED VENTILATION EMISSIONS