API MPMS 19.3D:2001(2012) pdf download

API MPMS 19.3D:2001(2012) pdf download.Manual of Petroleum Measurement Standards Chapter 19.3-一-Evaporative Loss Measurement Part D- -Fugitive Emission Test Method for the Measurement of Deck-Seam Loss Factors for Internal Floating-Roof Tanks.
3.2.3 Pressure
The unit of pressure is the pound-force per square inch absolute, designated psia.
3.2.4 Deck-Seam Loss Factors
The unit of reporting deck-seam loss factors is the pound- mole per foot of deck seani per year. designated lb-mole/ft yr.
The units of the deck-seam loss factor. Kd. do not actually indicate pound-moles of vapor loss over time, but rather are units of a factor that must be multiplied by certaill coeflicients (which are dimensionless) in order to deterini,ie the actual pound-moles of evaporative loss over time for a given liquid product. To convert the pound-mole per foot of deck seam per year units of the deck-seam loss factor to a loss rate in terms of actual pound-moles per foot of deck seam per year, the deck-seam loss factor, Kd. is multiplied by the dimensionless vapor pressure function, *, which is a function of the product vapor pressure and atmospheric pressure. and by the dimensionless product factor. K.
A pound-mole, designated lb-mole, is an amount of a substance the mass of which, when expressed in pounds, is equal to the numerical value of the molecular weight of the substance.
To then convert the actual pound-moles per foot of deck scam per year to pounds per year of a given liquid product. the loss rate (Kd P KL.) is multiplied by the total length of deck scam. Lj. having units of feet, and by thc molecular weight of the liquid product in its vapor phase. M1. having units of pounds per pound.molc. Additional information on this formula may be found in the API Manual of Petrolewn 4kasurt’,ne,,t Siandards, Chapter 19.2.
3.2.5 Deck-Joint Loss Factors
The unit of reporting deck-joint loss factors is the pound- mole per year per deck joint. designated lb-molc.yr.
The units of the deck-joint loss factor. K1. do not actually indicate pound-moles of vapor loss over time, hut rather art. units of a factor that must be multiplied by certain coeflicients (which arc dimensionless) in order to determine the actual pound-moles of evaporative loss over time for a given liquid product. To convert the pound-moles per deck joint per year Units of the deck-joint loss factoi- to a loss rate in terms of actual pound-moles per deck joint per year. the deck-joint loss factor. K1. is multiplied by the dimensionless vapor pressure function. P. which is a function of the product vapor pressure and atmospheric pressure. and by the dimensionless product factor. Kg..
To then convert the actual pound-moles per year per deck joint to pounds per year of a given liquid product, the loss rate (K1 P K) is multiplied by the dimensionless total number of floating roof deck joints. N1. and by the molecular weight of
4 Summary of Test Method
The test method described in this standard uses a mass balance procedure to measure a rate of evaporative loss through a test deck seam or a test deck joint. A test pan is fined with a test deck seam that may include a test deck joint. A test enclosure is placed over the test deck seam and is sealed to the top deck of the test pan. The test pan is tilled to an appropriate height with a volatile hydrocarbon test liquid of known properties, such as normal-hexanc or iso-hexanc. A measured flow rate of air is passed through the test enclosure and is controlled to maintain prescribed levels of pressure difference between the pressure in the test pan vapor space and the pressure in the test enclosure. The total hydrocarbon concentration in the air entering the test enclosure and in the air leaving the test enclosure are continuously measured using total hydrocarbon analyiers. A mass balance of the total hydrocarbon vapor in the air entering and in the air leaving the test enclosure is then made to determine the evaporative loss rate of hydrocarbon vapors through the test deck seam or test deck joint. The test enclosure loss rate is then factored for certain properties of the test liquid and the length of the test deck scam to determine an evaporative deck-scam loss factor or deck-joint loss factor.