RESUMO
Crude oil distillates are a highly useful industrial product, mainly for energy generation. Unfortunately, they are rarely studied, mainly due to the low accessibility to products directly obtained from the distillation process, which is a laborious, expensive, and time-consuming operation. This work presents and discusses the use of time-domain nuclear magnetic resonance (TD-NMR) as a simple, affordable, and straightforward tool for the development of correlations supported on the transverse relaxation time (T2 ) and boiling temperature. The results point out a high convergence between TD-NMR experimental data and the ASTM D2892 method for distillates from light, medium, and heavy oils, with up to 52.20% of accumulated mass and boiling point temperature (Tb ) up to 400°C. Furthermore, an unprecedented relationship between T2 values and the accumulated mass of the distillates is first demonstrated. This new insight opens new perspectives for future prediction of accumulated mass for unknown crude oils, placing the TD-NMR relaxometry as an appeal spectroscopy approach with a potential to meaningfully contribute to the daily refining petrochemical industry field operations.
Assuntos
Petróleo , Petróleo/análise , Destilação , Espectroscopia de Ressonância Magnética/métodos , Imageamento por Ressonância Magnética , TemperaturaRESUMO
Data in this paper covers in-cylinder pressure and volume, crank angle degrees as time magnitude, first derivate of in-cylinder pressure, admission pressure and injection pressure in a diesel engine fuelled with biodiesel. This data brings additional information such as ignition delay and rate of heat released. As condensed information, some graphs were obtained and are into the database such as in-cylinder vs. CAD, first derivate of in-cylinder pressure vs. CAD and ROHR vs. CAD. The data shows the measurements of the cylinder pressure behaviour of biodiesel from two different sources, which are both of interest of bioenergy industry at local scenarios (Jatropha curcas and Fatty Acid Distillates). Data in the paper are shown in Tables and Graphs. Through this data, a more accurate approach to engines performance and combustion can be reach, enhancing combustion efficiency and understanding of differences with standard diesel fuel.
RESUMO
The suitability of dispersive liquid-liquid microextraction (DLLME) and gas chromatography accurate mass spectrometry (GC-MS), based on a time-of-flight (TOF) MS analyzer and using electron ionization (EI), for the characterization of volatile and semi-volatile profiles of grape marc distillates (grappa) are evaluated. DLLME conditions are optimized with a selection of compounds, from different chemical families, present in the distillate spirit. Under final working conditions, 2.5â¯mL of sample and 0.5â¯mL of organic solvents are consumed in the sample preparation process. The absolute extraction efficiencies ranged from 30 to 100%, depending on the compound. For the same sample volume, DLLME provided higher responses than solid-phase microextraction (SPME) for most of the model compounds. The GC-EI-TOF-MS records of grappa samples were processed using a data mining non-targeted search algorithm. In this way, chromatographic peaks and accurate EI-MS spectra of sample components were linked. The identities of more than 140 of these components are proposed from comparison of their accurate spectra with those in a low resolution EI-MS database, accurate masses of most intense fragment ions of known structure, and available chromatographic retention index. The use of chromatographic and spectral data, associated to the set of components mined from different grappa samples, for multivariate analysis purposes is also illustrated in the study.