The importance of measuring the density of petroleum products in production, use, and storage and transportation

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The important significance of measuring the density of petroleum products in production, use, and storage and transportation lies mainly in the following points: ① It is used for the metering of petroleum products. During measurement, the volume v and density ρ are first determined, and then the mass of the petroleum product is calculated using the product of volume and density. 　　m = V20 (P20 – 0.0011) = KVt (P20 – 0.0011)
Where:
V20 – the standard volume, that is, the volume at 20°C, in L or m3;
ρ20 – the standard density, in g/cm³;
K – the volume coefficient of petroleum, which is the ratio of the volume of petroleum at 20°C to its volume at temperature t°C;
0.0011 – the correction factor for air buoyancy, in g/cm³;
Vt – the volume at temperature t°C, in m3.
② Different petroleum products have different densities, and by measuring the density, it is possible to roughly determine the type of petroleum product. The standard density ranges for common petroleum products are as follows: Petroleum product density range/(g/Cm3) ③ Measuring density can be used to roughly assess the quality and chemical composition of petroleum products. If a significant increase or decrease in the density of petroleum products is detected during storage and transportation, it can be determined whether heavy oil or light oil may have been mixed in. Or light fraction evaporation loss. In terms of chemical composition, aromatic hydrocarbons have the highest density, naphthenic hydrocarbons fall in the middle, while alkanes have the lowest density. Petroleum products with high levels of resin and asphaltenes also have a high density. 　　④The influence of fuel density on the performance of fuel oil. Both engine power and fuel consumption rate are related to fuel density; with the same tank volume, the higher the fuel density, the more fuel can be stored, and thus the greater the range. However, when the density is too high, it affects the atomization and combustion properties of the fuel; therefore, fuel product standards specify requirements for density. 　　The methods used in our country for determining the density of petroleum products include GB/T1884-92, Method for Determining the Density of Petroleum and Liquid Petroleum Products (Hydrometer Method). The specific instrument used for this purpose is the A1110 density meter. The hydrometer method is based on Archimedes’ principle: the buoyant force exerted by a liquid on an object submerged in it is equal to the mass of the liquid of the same volume that is displaced by the object. When the mass of the sample displaced by the densimeter when it is immersed in the sample is equal to its own mass, the densimeter is in equilibrium and floats freely within the sample. The greater the density of the sample, the less the densimeter is submerged; the lower the density of the sample, the more the densimeter is submerged. Since the immersion depth of the same densitometer varies in samples of different densities, the density of the sample can be determined during measurement by referring to the immersion scale value on the densitometer. The densitometer method is fast and simple, and is widely used in production and oil trade transactions. 　　The hydrometer method is based on measuring the mass of a certain volume of sample; it requires a small amount of sample, the measurement temperature is easy to control, and it offers high accuracy. However, the measurement time is long, making it suitable for scientific research.