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Engineering and Technology of Environmentally Friendly Lubricants
Published in Brajendra K. Sharma, Girma Biresaw, Environmentally Friendly and Biobased Lubricants, 2016
Carlton J. Reeves, Pradeep L. Menezes, Michael R. Lovell, Tien-Chien Jen
Low-temperature performance often refers to the pour point and the cloud point of fluids. The pour point is the lowest temperature at which the fluid still flows. Pour points for biobased lubricants exhibit the same dependencies as viscosity. With esters, short-chain branching of the alcohol lowers the pour point. However, this molecular structure also leads to a decrease in oxidative stability of the alcohol. For this reason, neopentyl-polyols are advantageous for the production of synthetic ester lubricants because their molecular structure is primarily composed of branched hydroxyl groups. Natural oils should have fewer saturated fatty acids and shorter chain length and branching for optimal low pour points [148–150], as shown in Figure 13.6. Saturated fatty acids exhibit excellent low-temperature properties, which improves with increased degree of unsaturation (Figure 13.6). However, increased unsaturation leads to high oxidation, which is not desirable. Short-chained saturated fatty acids are optimal for their cold-flow properties; as the chain length increases to 16–18 carbon atoms, these fatty acids become solid at temperatures of 65°C–75°C [74]. Research has shown that oils with high amounts of oleic acid are the best compromise between cold-flow properties and oxidative stability. High–oleic acid oils such as sunflower oil have pour points of −35°C. TMP polyolesters have pour points of −50°C [46,47].
Types and Properties of Lubricants
Published in W. S. Robertson, Lubrication in Practice, 2019
Different types of oils have widely different pour points. Those derived from paraffinic bases have a large amount of waxy components which make the oil stop flowing at a much higher temperature than oils derived from naphthenic bases, even if the naphthenic base oils have the same viscosity as the paraffinic base ones. Many finished oils are blends of both types of base oils and their pour points, and the pour points of purely paraffinic base oils, can be reduced by removing the waxy components from the oil. However, de-waxing is expensive. Another effective method of reducing pour points is to use additives – pour point depressants – to supplement a moderate amount of de-waxing.
Hydraulic System Fluids
Published in Anton H. Hehn, Fluid Power Troubleshooting, 1995
When hydraulic systems operate in a cold environment, there must be assurance that the fluid will flow properly to the suction side of the pump. Pour point is the lowest temperature at which the fluid will flow at atmospheric pressure. Many oils contain waxy components that tend to crystallize at low temperatures. When this occurs, the oil is at or near its pour point. The hydraulic system becomes inoperative. So, the fluid chosen for a hydraulic system must have a pour point below the lowest anticipated startup temperature.
Simulation of oil flow in a heat traced piping segment – COMSOL versus analytical trends
Published in Petroleum Science and Technology, 2023
Salah H. Bayoumy, Sahar M. El-Marsafy, Tamer S. Ahmed
Oil flow requires high pumping and heating costs particularly when it has a high content of asphaltenes and waxes (Martínez-Palou et al. 2011). The thermal treatment, chemical treatment, and oil blending are enhancement methods used to improve the oil flow characteristics in a piping segment. Blending the heavy oil with a light oil fraction facilitates the oil pumping and decreases the pumping expenditures (Hasan, Ghannam, and Esmail 2010; Gao and Li 2012). As an example of the chemical treatment methods, pour point depressants decrease the formation of waxes agglomeration (Chen, Zhao, and Yin 2010; Yao et al. 2022). However, oil characteristics variation usually affects the effectiveness of the pour point depressants and oil flow is deteriorated unless the heat tracing is working properly.
Research progress of new nanocomposite pour point depressant: a mini-review
Published in Petroleum Science and Technology, 2021
Huili Zhang, Hailin Yu, Yu Gao, Wei Jiang, Jinjun Deng
In crude oil transportation, especially under low temperature conditions, paraffin wax will precipitate from the crude oil, which will affect pipeline transportation, making the pipeline transportation process of crude oil facing huge challenges. Therefore, it is particularly important to improve the low-temperature fluidity of crude oil, reduce the energy consumption during the transportation process, and reduce the risk of the transportation process. Adding a pour point depressant is an effective way. Conventional polymer pour point depressants have many shortcomings, and they can no longer meet people’s needs. Therefore, as far as the preparation of NPPD is concerned, the in situ polymerization method is currently the best choice for the preparation of NPPD because of its good dispersibility, good effect on crude oils and low dosage. The current research on NPPD only stays in the selection of natural or synthetic nanomaterials with regularity. Due to the heterogeneous nucleation mechanism, the wax crystal image observed by polarized light microscope is similar to the nanoparticle morphology in the NPPD used. As for the microscopic observation of wax crystals in oil by NPPD, it has not been determined which morphology of nanomaterials prepares the best NPPD effect. Therefore, synthesizing nanomaterials with different morphologies and structures to change NPPD has far-reaching significance for crude oil nucleation sites. Moreover, it will be a new trend in the future to search for nanomaterials with certain pores and then synthesize a new type of NPPD with a lower waxing point in crude oil.
Effect of organic solvents and acidic catalysts on biodiesel yields from primary sewage sludge, and characterization of fuel properties
Published in Biofuels, 2021
Mohamed A. Gomaa, Nicolas Gombocz, Dominik Schild, Farouq S. Mjalli, Ahmed Al-Harrasi, Raeid M.M. Abed
The biodiesel cloud point was measured according to the ASTM D 2500 method, where the samples were gradually cooled from room temperature until the first sign of a cloud forming at the bottom of the sample was observed. Cloud point is the temperature at which the first wax crystals appear when a liquid is cooled. The pour point is the lowest temperature at which the fuel can still flow or be pumped. The pour point was measured according to ASTM D 97, where the samples were first cooled to freezing and then gradually heated until the lowest temperature at which movement was observed. For further analysis of the produced biodiesel, Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR) were performed to confirm the presence of FAME. FTIR was performed using a Perkin Elmer STA 6000 with a spectrum observing the range of 4000–400 cm−1. For 1H-NMR analysis, a Bruker Avance III HD spectrometer operating at 700 MHz was used with CDCl3 as a solvent. The 1H-NMR spectrum obtained was used to calculate the conversion efficiency of primary sludge to FAME according to the following equation [28]: where C% is the conversion efficiency to FAME (as a percentage), and AME and Aα-CH2 are the areas of methoxy and methylene protons, respectively.