api gravity что это

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Формулы плотности в градусах API

Формула для расчета плотности в градусах API от удельного веса (SG):

И наоборот, удельный вес нефтяных жидкостей может быть получен из их значения плотности в градусах API как

SG в 60 ∘ F знак равно 141,5 Плотность в градусах API + 131,5 <\ displaystyle <\ text >

60 ^ <\ circ><\ text > = <\ frac <141.5><<\ text > + 131,5>>>

Таким образом, тяжелая нефть с удельным весом 1,0 (т. Е. С той же плотностью, что и чистая вода при 60 ° F) имеет плотность в градусах API:

Использование плотности в градусах API для расчета баррелей сырой нефти на метрическую тонну

баррелей сырой нефти на метрическую тонну знак равно Плотность в градусах API + 131,5 141,5 × 0,159 <\ displaystyle <\ text <баррелей сырой нефти на метрическую тонну>> = <\ frac <<\ text > + 131,5> <141,5 \ times 0,159>>>

Например, метрическая тонна West Texas Intermediate (39,6 ° API) имеет объем около 7,6 баррелей.

Измерение удельного веса в градусах API

Масло SG знак равно ρ сырая нефть ρ ЧАС 2 О <\ displaystyle <\ mbox > = <\ frac <\ rho _ <\ text >> <\ rho _ <<\ text > _ <2><\ text > >>>>

Прямое измерение плотности в градусах API (метод ареометра)

Есть преимущества полевых испытаний и бортового преобразования измеренных объемов в поправку на объем. Этот метод подробно описан в ASTM D287.

Классификации или степени

Вообще говоря, самые высокие цены на нефть с плотностью API от 40 до 45 °. Выше 45 ° молекулярные цепи становятся короче и менее ценными для нефтеперерабатывающих заводов.

Сырая нефть классифицируется как легкая, средняя или тяжелая в зависимости от ее измеренной плотности в градусах API.

Однако не все стороны используют одинаковую оценку. Геологическая служба США использует несколько различных диапазонов.

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API gravity

Смотреть что такое «API gravity» в других словарях:

API gravity — The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and… … Wikipedia

API gravity — An arbitrary scale expressing the gravity, or density, of liquid petroleum products in terms of API degrees. Relationship of the API scale to specific gravity is expressed by the equation ºAPI = (441.5/sp gr 60/60F) 131.5. ASTM D 287 is the… … Petroleum refining glossary

API Gravity — Universally accepted scale, adopted by the API, to express the specific gravity of oils. It serves as a rough measure of quality. The higher the API gravity number, the richer the yield in premium refined products. ► See also API … Financial and business terms

API gravity — American Petroleum Institute measure of specific gravity of crude oil or condensate in degrees. An arbitrary scale expressing the gravity or density of liquid petroleum products. The measuring scale is calibrated in terms of degrees API; it is… … Energy terms

API gravity — see degree API … Dictionary of units of measurement

API gravity — noun A specific gravity scale measuring the relative density of various petroleum liquids, expressed in degrees … Wiktionary

API (disambiguation) — API, originally Advanced Programming Interface but now more commonly known by its near synonym, Application programming interface, is any defined inter program interface.API or api may also refer to:* Api (mountain), a mountain in Nepal * API… … Wikipedia

Gravity (chemistry) — In chemistry, gravity is the density of a fluid, particularly a fuel. It is expressed in degrees, with lower numbers indicating heavier liquids and higher numbers indicating lighter liquids. See specific gravity and API gravity … Wikipedia

API oil-water separator — An API oil water separator is a device designed to separate gross amounts of oil and suspended solids from the wastewater effluents of oil refineries, petrochemical plants, chemical plants, natural gas processing plants and other industrial… … Wikipedia

Плотность в градусах API — Плотность в градусах API единица измерения плотности нефти, разработанная Американским институтом нефти. Измерения в градусах API позволяют определить относительную плотность нефти по отношению к плотности воды при той же температуре. По… … Википедия

Densité API — La densité API est une échelle permettant d exprimer la densité du pétrole brut, en degrés API (° API), calculée à partir de la densité, par la formule suivante : Densité API = (141.5/(densité à 60 °F)) – 131.5 Plus un brut est léger, plus… … Wikipédia en Français

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API gravity

From Wikipedia, the free encyclopedia

The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water: if its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks.

API gravity is thus an inverse measure of a petroleum liquid’s density relative to that of water (also known as specific gravity). It is used to compare densities of petroleum liquids. For example, if one petroleum liquid is less dense than another, it has a greater API gravity. Although API gravity is mathematically a dimensionless quantity (see the formula below), it is referred to as being in ‘degrees’. API gravity is graduated in degrees on a hydrometer instrument. API gravity values of most petroleum liquids fall between 10 and 70 degrees.

In 1916, the U.S. National Bureau of Standards accepted the Baumé scale, which had been developed in France in 1768, as the U.S. standard for measuring the specific gravity of liquids less dense than water. Investigation by the U.S. National Academy of Sciences found major errors in salinity and temperature controls that had caused serious variations in published values. Hydrometers in the U.S. had been manufactured and distributed widely with a modulus of 141.5 instead of the Baumé scale modulus of 140. The scale was so firmly established that, by 1921, the remedy implemented by the American Petroleum Institute was to create the API gravity scale, recognizing the scale that was actually being used. [1]

YouTube Encyclopedic

Transcription

[MUSIC PLAYING THROUGHOUT] What does «specific gravity» mean? The specific gravity of an object is the density of that object divided by the density of water. The density of water is 1,000 kilograms per meter cubed. For instance, the density of gold is 19,300 kilograms per meter cubed. So the specific gravity of gold is 19.3. The density of ketchup is 1,400 kilograms per meter cubed. So the specific gravity of ketchup up is 1.4. Note, there’s no units for specific gravity, because it’s the ratio of one density to another density. So the units cancel each other out. OK, so why even bother defining something called the specific gravity? Well, one really cool thing about specific gravity is that, for something that floats, the specific gravity tells you the fraction of that object that will be below the water while it’s floating. For instance, say you let a cube of wood with specific gravity 0.2 float in water. Since the specific gravity is 0.2, that means that 20% of the total volume of this wood is going to be submerged below the water while it’s floating. If the cube of wood had a specific gravity of 0.6, 60% of the wood would be submerged beneath the water’s surface. Ice has a density of about 920 kilograms per meter cubed. That means ice has a specific gravity of 0.92. And that’s why 92% of an iceberg’s volume is actually underneath the water. But what if we were to use a cube that had a density of 2,700 kilograms per meter cubed? The specific gravity would be 2.7, which means that 270% of this cube would be submerged beneath the water. But you can’t have more than 100% of an object submerged. Even if the object were to sink, the maximum amount submerged would be 100%. So if the specific gravity of an object is greater than 1, that object is going to sink if placed freely in water. And it’ll have exactly 100% of its volume submerged. Usually when people are referring to the specific gravity, they’re referring to the density of the object divided by the density of water. But sometimes it’s useful to define the specific gravity with respect to a liquid that’s different from water. For instance, if you were to let some wood of density 638 kilograms per meter cubed float in oil that has a density of 850 kilograms per meter cubed, you could still find the percent of the wood that’s submerged underneath the oil. Just use the density of oil instead of the density of water in the specific gravity formula. If we do that, we’ll find that the wood does float in this oil with 75% of the wood’s volume submerged beneath the surface of the oil. [MUSIC PLAYING]

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API Gravity

API expresses the gravity or density of liquid petroleum products. Online API to Specific Gravity calculator.

API Gravity can be calculated as:

°API = Degrees API Gravity

Specific gravity can be calculated from API gravity:

Note! Oil with the least specific gravity has the highest API gravity

Density is a temperature depedent property. API gravity increases with increasing temperature, while specific gravity decreases with increasing temperature. See correlations at Density of crude oil as function of temperature. This means that the volume of a petroleum liquid increases with increasing temperature, and that a density number always must be given with the measurement temperature. The standard measuring temperature is 15°C or 60°F.

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What is API Gravity?

Have you heard of API gravity? If you don’t work in the petroleum industry, this term might have passed you by. Which is why we’ve put together this useful guide covering what it is, how it’s used and where it came from.

Industry indicator

API gravity is short for American Petroleum Institute gravity, an inverse measure that is used to determine the weight of petroleum liquids in comparison to water. If a liquid has API gravity of more than 10 it is considered a light oil that floats on water. If the liquid’s API gravity is less than 10 it will sink and falls into the heavy oil category. While API gravity essentially measures the relative density of petroleum liquid and water it is primarily used to evaluate and contrast the relative densities of petroleum liquids.

In mathematical terms API gravity has no dimensions. However the measure is gradated in degrees using a purpose built hydrometer instrument. Thanks to a strategic API scale design most petroleum liquids will be categorised between 10 and 70 API gravity degrees.

The origins of API gravity

The original technique used to measure the gravity of liquids was called the Baumé scale. It was developed in France in 1768 and officially accepted by the U.S. National Bureau of Standards in 1916. After encountering a series of errors and variations the American Petroleum Institute refined the scale and created API gravity. This is now widely used across the globe.

Clear-cut formulas

The official formula used to derive the gravity of petroleum liquids from the specific gravity (SG), as follows:

API gravity = 141.5/SG – 131.5

The relative density of petroleum liquids can also be uncovered by using API gravity value:

RD at 60 o F = 141.5 / (API gravity + 131.5)

A key formula for establishing barrels of crude oil per metric ton

Using the following formula, API gravity can also be used to calculate how many barrels of crude oil can be produced per metric ton. Given that the weight of an oil plays an integral role in establishing its market value this formula is incredibly important!

Barrels of crude oil per metric ton = 1 / [141.5 / (API gravity + 131.5) x 0.159]

API gravity classifications and grades

In general oils with API gravity of 40 – 45 generate the highest market prices. Any oils with API gravity of 45 or over have shorter molecular chains which are less desirable to refineries. Below is an overview of the four major crude oil classifications:

Light crude oil

Any crude oil with API gravity of over 31.1 degrees falls into the light crude oil category.

Medium crude oil

Oils with API gravity falling between 22.3 and 31.1 degrees are classed as medium crude oils.

Heavy crude oil

Heavy crude oils have API gravity of under 22.3.

Extra heavy oil

Also referred to as bitumen, extra heavy crude oils have API gravity of below 10.0 degrees.

While these are accurate classifications it’s important to note that exact differentiations between light, medium, heavy and extra heavy will vary depending on the region of origin. At the end of the day, fluctuations are largely based on current oil commodity trading.

What next?

If you’d like to learn more, take a look at this article: Density Measurement in the Petroleum Industry. Density is one of the most prevalent physical property used to classify and characterise fluids, not only in the environmental, cosmetics, pharmaceuticals, and food and beverage industries, but also in hydrocarbon processing industry (HPI). Used in conjunction with the specific-industry API Gravity scale, its accurate and precise measurement is necessary for converting the measured volumes into volumes at reference temperatures (15°C; 20°C and 60°F).

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