This test method covers and specifies a procedure for the concurrent measurement of both the dynamic viscosity, η, and the density, ρ, of liquid petroleum products and crude oils, both transparent and opaque. The kinematic viscosity, ν, can be obtained by dividing the dynamic. ASTM De2. Standard Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity). that measures according to ASTM D It is an excellent alternative to conventional capillary viscometry for fast and economical measurement of the.

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ASTM D - Quick delivery via download or delivery service. Buy securely with a credit card or pay upon receipt of invoice. All transactions are. Saybolt viscosity (ASTM D). Dynamic viscosity (ASTM D). Density (EN ISO , ASTM D, IP ). Viscosity Index (VI) (ISO , ASTM D). sponsored by ASTM Committee D02 on Petroleum Products and Lubricants and . D 81 by thermohydrometer method. D 82 of viscous materials by.

Introduction Petroleum is a complex mixture of hydrocarbons of varying nature and small fractions of nitrogen, oxygen, sulfur, and metal compounds. Under high temperature and pressure, as encountered at reservoirs e. A large portion of the Brazilian oil production comes from offshore fields, from the pre-salt layer. These oils have high levels of waxes, which are alkanes linear or branched encompassing carbonic chains of 15—75 carbons [ 3 , 4 ]. In temperatures below the wax appearance temperature WAT , the wax crystallization takes place with subsequent deposition [ 2 ]. The wax deposition is dominated by the molecular diffusion mechanism [ 8 ] in which the waxes initially precipitate at the cold pipeline walls and subsequently generate a radial gradient of precipitation causing deposit [ 9 , 10 ].

In this work, the length measurements were performed on images obtained by BF, but the PL images are shown due to easy observation. Another characteristic of wax crystals that can be seen in Figure 1a is a roughened surface.

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The roughness, as well as the tortuosity of wax crystals, can be attributed to a heterogeneous nucleation and growth, by the presence of asphaltenes, resins, and different wax chain lengths or the presence of isocycle [ 24 , 31 ]. In order to characterize the wax morphology and crystals length in dependence of temperature and shear, a continuous cooling protocol was performed Figure 2. This condition is sufficient to dissolve all wax present in the crude oil and prevent that the wax crystal formation was not influenced by pre-existing nuclei [ 32 , 33 ].

The cooling rate was 0.

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Figure 2. It was verified that experiments performed with quiescent condition Figure 2A — D were characterized by large crystals and cluster of crystals when compared with experiments carried out with shear condition Figure 2E — H. The researchers carried out by [ 2 , 16 , 34 ] show that under quiescent conditions, the waxy crystals were characterized by extended and continuous particles.

The formation of extended and continuous particles allowed a colloidal network that embodies the oil itself. Probably, the gel would have a high shear modulus, in order to the side-by-side interactions between particles. Under the shear condition, the lateral growth of the individual crystals is constricted.

However, extended particles are not observed, and consequently, these particles lost their interconnectivity. The wax crystals presented in waxy crude oils Figure 2 are elongated. According to [ 16 ], waxes precipitated in crude oil tend to crystallize in an orthorhombic structure, which is characterized by an elongated structure. Evidently, the crystals of Figure 2 and in detail in Figure 1 are not linear needle-like. The sinuosity and tortuosity are probably due to the presence of impurities during nucleation and crystal growth processes [ 2 , 21 ].

Based on aspect ratio value, it is possible to verify how the structure is elongated. P4 sample has a 4. Table 1.

This behavior could be attributed to a possible crystal breakage by the shear, which prevents the crystals from becoming large. The average percentage of growth between quiescent and shear conditions increases with the temperature decrease.

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High viscosity fuels on the other hand will increase gear-train, cam and follower wear on the fuel pump assembly due to the higher injection pressures. Diesel fuels with high viscosity also tend to form larger droplets on injection, causing poor combustion and increased smoke and emissions. Fuels that do not meet viscosity requirements lead to loss of performance.

Sulphur Diesel with higher sulphur content produces more exhaust particulate emissions than diesel with a lower sulphur content which has major environmental implications. Local and international regulatory bodies have lowered the allowable percentage of sulphur in diesel to 0.

Most diesel vehicles function optimally with 0. Distillation Measures the temperature range over which a fuel turns to vapour. Volatility is one of the primary methods which distinguish various fuels from one another. According to [ 29 ] it allows verifying the anisotropic optical behavior of crystalline materials, named birefringence. This technique uses two cross polarizers.

When the light beam passes through crystalline structures, as wax crystals, the polarized light plane is altered generating a visible image pattern. On the other hand, isotropic structures, which do not exhibit the same level of organization, are not able to modify the light plane. Apart from PL microscopy, the bright-field BF microscopy regards another important technique for wax crystal visualization. The procedure is very simple, and no artifacts are employed in the optical path. Figure 1.

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The BF technique Figure 1a provides lower contrast than PL technique Figure 1b ; however, it can be seen that in BF micrographs the wax crystal is continuous, i. Therefore, much attention should be taken to make length measurements in crystals observed by PL technique.

According to these results, to determine the size and crystal shape as verified by BF can be critical to avoid erroneous measurements. In this work, the length measurements were performed on images obtained by BF, but the PL images are shown due to easy observation.

Another characteristic of wax crystals that can be seen in Figure 1a is a roughened surface. The roughness, as well as the tortuosity of wax crystals, can be attributed to a heterogeneous nucleation and growth, by the presence of asphaltenes, resins, and different wax chain lengths or the presence of isocycle [ 24 , 31 ].

In order to characterize the wax morphology and crystals length in dependence of temperature and shear, a continuous cooling protocol was performed Figure 2. This condition is sufficient to dissolve all wax present in the crude oil and prevent that the wax crystal formation was not influenced by pre-existing nuclei [ 32 , 33 ].

The cooling rate was 0. Figure 2. It was verified that experiments performed with quiescent condition Figure 2A — D were characterized by large crystals and cluster of crystals when compared with experiments carried out with shear condition Figure 2E — H. The researchers carried out by [ 2 , 16 , 34 ] show that under quiescent conditions, the waxy crystals were characterized by extended and continuous particles. The formation of extended and continuous particles allowed a colloidal network that embodies the oil itself.

Probably, the gel would have a high shear modulus, in order to the side-by-side interactions between particles. Under the shear condition, the lateral growth of the individual crystals is constricted.

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