1、Manual of PetroleumMeasurement StandardsChapter 19.6Part 1Evaporative Loss from Storage Tank Floating-roof LandingsFIRST EDITION, FEBRUARY 2017Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local,state, and federal laws and r
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14、tor.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A one-timeextension of up to two years may be added to this review cycle. Status of the publication can be ascertained from theAPI Standards Department, telephone (202) 682-8000. A catalog of A
15、PI publications and materials is publishedannually by API, 1220 L Street, NW, Washington, DC 20005.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW,Washington, DC 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . .
16、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Vari
17、ables and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Proposed Estimating Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、 . . . 34.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.2 Standing Idle Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . . . . 34.3 Filling Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.4 Total Landing Loss . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.5 Landing Loss Estimation Equations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Description of Concentration and Saturation . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 Description of Floating-roof Landing Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.1 Landing Loss Events . . . . . . . . . . . . . . . . . . . . . . . .
22、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106.2 Standing Idle Loss Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116.3 Filling Loss Mechanism . . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206.4 Properties of the Liquid Heel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247 Sample Calculations . . . . . .
24、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247.1 Accounting for Cone-down Bottoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247.2 Worked Examples . .
25、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26、. . . . 27Annex A (informative) Summary of the Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Annex B (informative) Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27、 . . . . . 31Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Figures1 Vacuum-breaker Vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
28、 . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Standing Idle Loss (Emissions). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Filling Loss (Emissions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Tank with a Liquid Heel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Drain-dry Tank . . . . . . . . . . . . . . . . . . . . . . . .
30、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Wind Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Wind Effects . . . . . . .
31、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Saturation Pattern of Drain-dry Tanks versus Tanks with a Liquid Heel . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Volume of Vapor Above a Liquid H
32、eel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2510 Volume of Vapor in a Cone-down Bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2511 Saturation Factors: Internal Floating
33、-roof Tanks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Tables1 Summary of Floating-roof Landing Loss Estimation Methods by Tank Type (per Episode) . . . . . . . . . . . 52 Properties of Selected Petroleum Stocks. . . . . . . . . . . . . . . . . . . .
34、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Effective Height of Liquid, hle, and Height of Vapor Space, hv. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26vIntroductionThe purpose of this study was to investigate storage tank emissions that may result
35、 from landing and subsequentlyrefloating a floating roof. The existing emission factors for floating-roof tanks 2,22are based on the assumption thatthe floating roof is continuously floating on the stored stock liquid. Additional emissions may occur, however, if thetank is emptied such that the floa
36、ting roof is no longer floating.When the liquid level approaches the bottom of the tank, the floating roof lands on deck legs or other supports thatprevent it from dropping any further as the stock liquid continues to be removed. Further withdrawal of stock liquidcould then potentially form a partia
37、l vacuum beneath the landed floating roof. If the receding liquid were to create anexcessive partial vacuum, the floating roof could collapse. To avoid this condition, a vacuum-breaker vent on thefloating roof opens automatically as the floating roof lands (see Figure 1). The vapor space created und
38、er the floatingroof is thereby freely vented to the space above the floating roof. Even in the case of a self-closing vacuum-breaker,the vapor space beneath the floating roof is vented via the other deck fittings and the rim seal, which is effectivelyrendered vapor mounted once the liquid level drop
39、s below the bottom of the rim seal. Vapor loss (and the corresponding emissions to the atmosphere) may occur while the tank remains nominally emptyand the floating roof continues to stand idle in this landed condition (see Figure 2). Additional emissions may occurduring the refilling of the tank, as
40、 the vapor space beneath the floating roof is displaced by the incoming stock liquid(see Figure 3). This study sought to quantify these floating-roof landing loss emissions.vi1 Evaporative Loss from Storage Tank Floating-roof Landings 1 Scope The emissions characterized as floating-roof landing loss
41、es in this study are those that would be expected to occur if a floating roof is landed in the course of normal operations and subsequently refilled. This study does not address emissions that may result from additional activities, such as degassing or tank cleaning, that may occur while the tank is
42、 empty. The model is intended for use with any petroleum liquid. The inclusion in the model of the stock liquids physical properties (i.e. true vapor pressure, vapor molecular weight, and liquid density) appears to effectively differentiate crude oil from gasoline, and therefore no further different
43、iation was made in the form of product factors or other product-specific adjustments. The model does not directly address standing idle losses for partial days, but it would be reasonable to estimate the emissions for a partial day by estimating the standing idle emissions for a single day and then
44、prorating that estimate by the number of hours that the floating roof was actually landed. Any emission factor is properly understood as representative of the actual emission rates that are typical for a population of emission points. For a non-uniform population, however, there is an inherent level
45、 of uncertainty associated with the application of the general emission factor to any individual emission point. Some of the critical sources of uncertainty in this model of floating-roof landing losses are addressed in the comments on the confidence associated with each step of the model. As noted
46、in these comments, some of the variables have not been well defined, and the values shown are intended to serve only as placeholderspending further research. 2 Normative References The following documents are indispensable for the application of this document. For dated references, only the edition
47、cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API MPMS Chapter 19.1, Evaporative Loss from Fixed-roof Tanks API MPMS Chapter 19.2, Evaporative Loss from Floating-roof Tanks API MPMS Chapter 19.4, Evaporative Loss Reference In
48、formation and Speciation Methodology API MPMS Chapter 19.5/EI Hydrocarbon Management HM 65 1, Atmospheric Hydrocarbon Emissions from Marine Vessel Transfer Operations API Technical Report 2568, Evaporative Loss from the Cleaning of Storage Tanks 3 Variables and Symbols Symbol Description Units Sourc
49、e B constant from Antoines equation R from Table 2 (for historical purposes only) Csffilling saturation correction factor dimensionless (25)Equation(5)Equation(5)Equation(19)Equation1+= (29) 1Energy Institute, 61 New Cavendish Street, London W1G 7AR, UK, www.energyinst.org. 2 API MPMS CHAPTER 19.6.1 Symbol Description Units Source ( )( )+=SMTRVPKMTRVPKKMTRVPKMPDC111157.01VVVVASVVVVAESVVVVAEVsf*D tank diameter ft as specified by the user hleeffective height of the stock liquid ft as specifi
