API MPMS 19.1-2017 pdf free download

API MPMS 19.1-2017 pdf free download.Manual of Petroleum Measurement Standards Chapter 19.1 Evaporative Loss from Fixed-roof Tanks.
1 Scope This standard contains methodologies for estimating the total evaporative losses of hydrocarbons from fixed-roof tanks. The methodologies provide loss estimates for general equipment types based on laboratory, test-tank, and field-tank data. Types of fixed-roof tanks and roof fittings described are for information only. The equations estimate average annual losses from fixed-roof tanks for various liquid stocks, stock vapor pressures, tank sizes, meteorological conditions, and operating conditions. The following special cases are addressed: a) horizontal tanks, b) higher volatility stocks (true vapor pressure greater than 0.1 psia), c) vent settings higher than 0.03 psia (0.5 oz/in. 2 ), d) tanks that have either roof or shell insulation. The estimation may be improved by using detailed field information, including climatic data and operational data for the appropriate time period. The equations are not intended to be used in the following applications: a) to estimate losses from unstable or boiling stocks or from petroleum liquids or petrochemicals for which the vapor pressure is not known or cannot readily be predicted [to calculate emissions from tanks that contain material at or above its boiling point or the point at which material starts to flash, the API model E&P Tank (API 4697) can be used]; b) to estimate losses from fixed-roof tanks that have an internal floating roof (API MPMS Ch. 1 9.2 [4] and API 2569 [1 3] address these); c) to estimate losses from cleaning fixed-roof tanks (API 2568 [1 2] addresses this); d) to estimate losses from tanks with air sparging operations.
6.5 Outside Surfaces of the Tank Painting the tank shell and roof reduces evaporative loss and preserves the tank. Highly reflective surfaces, such as mill-finish aluminum or surfaces painted white, result in lower tank metal temperatures and lower heat input to the tank, reducing the standing loss. Tank paint inspection and maintenance preserve the paint reflectance and reduce corrosion of the tank. Unpainted aluminum dome roofs provide a highly reflective surface while avoiding the maintenance required for paint. 7 Loss Mechanisms 7.1 General Evaporation is the natural process in which a liquid is converted to a vapor. Through evaporation, all liquids establish an equilibrium concentration of vapors above the liquid surface. Every liquid stock has a finite vapor pressure that depends on the surface temperature and composition of the liquid and that causes the liquid to evaporate. Under static conditions, an equilibrium vapor concentration is established, after which no further evaporation occurs. However, fixed-roof tanks are exposed to dynamic conditions that disturb this equilibrium, causing additional evaporation. These dynamic conditions are responsible for continued evaporation, resulting in stock loss and atmospheric emissions. Evaporation loss from fixed-roof tanks occurs when the evaporated vapor escapes the tank and goes into the atmosphere. The total evaporative loss from a fixed-roof tank is the sum of the standing loss and the working loss. 7.2 Standing Loss Standing loss is the evaporative loss of stock vapor resulting from the thermal expansion and contraction of the tank air-vapor mixture resulting from the daily heating cycle. This loss is also called breathing loss and occurs without any change in liquid level in the tank.
6.5 Outside Surfaces of the Tank Painting the tank shell and roof reduces evaporative loss and preserves the tank. Highly reflective surfaces, such as mill-finish aluminum or surfaces painted white, result in lower tank metal temperatures and lower heat input to the tank, reducing the standing loss. Tank paint inspection and maintenance preserve the paint reflectance and reduce corrosion of the tank. Unpainted aluminum dome roofs provide a highly reflective surface while avoiding the maintenance required for paint. 7 Loss Mechanisms 7.1 General Evaporation is the natural process in which a liquid is converted to a vapor. Through evaporation, all liquids establish an equilibrium concentration of vapors above the liquid surface. Every liquid stock has a finite vapor pressure that depends on the surface temperature and composition of the liquid and that causes the liquid to evaporate. Under static conditions, an equilibrium vapor concentration is established, after which no further evaporation occurs. However, fixed-roof tanks are exposed to dynamic conditions that disturb this equilibrium, causing additional evaporation. These dynamic conditions are responsible for continued evaporation, resulting in stock loss and atmospheric emissions. Evaporation loss from fixed-roof tanks occurs when the evaporated vapor escapes the tank and goes into the atmosphere. The total evaporative loss from a fixed-roof tank is the sum of the standing loss and the working loss. 7.2 Standing Loss Standing loss is the evaporative loss of stock vapor resulting from the thermal expansion and contraction of the tank air-vapor mixture resulting from the daily heating cycle. This loss is also called breathing loss and occurs without any change in liquid level in the tank.