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Base Oils
Published in Wilfried J. Bartz, Engine Oils and Automotive Lubrication, 2019
Field desorption-mass spectrometry has been used to characterise wide variety of compound types which are commonly used in synthetic lubricant formulations. The technique’s ability to deal with compounds which vary widely in their polarity and thermal stability characteristics make it a particularly powerful tool in application area. The mechanisms involved in field desorption/ionisation involve very low internal energy transfer and the resultant mass spectra are dominated by molecular ion species. Field desorption/ionisation mass spectrometry provides an elegant approach to thecharacterisation of a wide range of compound types used in lubricant formulations. The technique’s ability to deal with compounds of widely differing polarity and thermal characteristics in a single experiment make it an attractive tool in the analysis of complex mixtures. The instrument will be equipped with a multichannel plate array detector which very effectively overcomes traditional problem of low ion currents generated during field desorption ionisation thus giving access to extra dimension of MS-MS information which this combination will permit.
Gas content prediction model of water-sensitive shale based on gas–water miscible competitive adsorption
Published in Petroleum Science and Technology, 2022
Rui Huang, Qun Lei, JunBin Chen, DingWei Weng, Xiaoming Wang, Hongbo Liang
As shown in Table 3, by comparing the calculation results of adsorbed gas content, free gas content, and total gas content of the two models, it can be seen that the adsorbed gas content and free gas content of water-bearing shale are apparently lower than those of dry shale, which is mainly caused by formation water. When the molecules of methane and water simultaneously compete for the adsorption sites on the shale surface, water molecules are first adsorbed on the inner surface of pores or fractures to form hydration film due to the strong hydrophilicity of clay minerals, which reduces the amount of methane adsorption. Moreover, the hydration swelling of clay minerals leads to the decrease of effective pore size and free gas accumulation. Considering that the spread area of hydration film may not be enough to completely cover the inner surface of pores (or fractures), the gas content prediction model of gas–liquid–solid three-phase interface competitive adsorption can be established to calculate the total gas content under different water saturation. Compared with the field desorption data of shale cores in Jiaoshiba area, Fuling, China, the calculation error of dry shale model is 53.2%, and that of water-bearing shale model is 6.1%. The latter is much closer to the actual gas content of the reservoir. Therefore, the gas content prediction model of gas–liquid–solid three-phase interface competitive adsorption stands out and provides a more accurate resource evaluation method for shale gas reservoirs with different water content than previous ones.
Transformation of asphaltenes of vacuum residues in thermal and thermocatalytic processes
Published in Petroleum Science and Technology, 2022
Akim S. Akimov, Nikita N. Sviridenko
For a long time, the study of the properties of asphaltenes (determination of the molecular mass, particle size, structure, and morphology) has been an extremely difficult task. First of all, this was due to their tendency to agglomeration. However, an analysis of publications over the past 15–20 years has shown obvious progress in studying the properties of asphaltenes (Ganeeva, Yusupova, and Romanov 2011; Schuler et al. 2015; Rogel and Witt 2017; Chen et al. 2018). For example, it has been found out using new mass spectrometric methods of analysis such as Laser Desorption Ionization-Mass Spectrometry (LDI-MS), Atmospheric Pressure Photoionization-Mass Spectrometry (APPI-MS), Field Ionization-Mass Spectrometry (FI-MS), Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR-MS), and Field Desorption and Field Ionization Mass Spectrometry (FD-FI-MS) that the molecular mass of asphaltenes varies within the range 300–1400 g·mol−1. Summary of results of measurement of molecular diffusion by various methods revealed that the size of the asphaltene molecule was in the range from 1.2 to 2.4 nm. The methods used were as follows: fluorescence correlation spectroscopy (FCS), time-resolved fluorescence depolarization (TRFD), 1H diffusion ordered spectroscopy magnetic resonance (1H DOSY NMR), high resolution transmission electron microscopy (HRTEM), small angle X-ray scattering (SAXS), and X-ray Raman spectroscopy (XRRS).
On-site comparison of the OSHA 47, Asset EZ4-NCO, Iso-Chek, DAN, and CIP10 methods for measuring methylene diphenyl diisocyanate (MDI) at an oriented-strand board (OSB) factory
Published in Journal of Occupational and Environmental Hygiene, 2020
Simon Aubin, El Mekki Hamdi, Audrey Joly, Philippe Sarazin, Jacques Lesage, Livain Breau, Mark Spence, Sébastien Gagné
All samplers except the CIP10 and Asset EZ4-NCO were operated at a sampling flow rate of 1 L/min, which was achieved by pumps (model 224-PCXR4, SKC Inc., Eighty Four, PA, USA). For the Asset samplers, SKC pumps model 222-3 were used to achieve 0.2 L/min. The CIP10 has its own aspiration mechanism providing 10 L/min. The initial CIP10M calibration used a TSI 4043 flowmeter (Shoreview, MN, USA) and a calibration device supplied by Arelco. The flow rate was then verified in the field using a 6236SI tachometer, also supplied by Arelco. All other flow rates were adjusted to their designated value prior to sampling and verified at the end of sampling with a TSI flowmeter 4140 (TSI Inc., Shoreview, MN, USA). Across the sample period, all flow rates were within ± 5%; therefore, no samples were discarded. A modification was made to OSHA 47 protocol to include the field desorption of the samples.