Petroleum heteroatom compounds in various commercial delayed coking liquids： characterized by FT-ICR MS and GC techniques

Delayed coking is an important petroleum resid conversion process.The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids.Eight commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic techniques.High relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and naphthobenzothiophenes.Coking liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).However,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process.The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.

Resin composition: An indicator of oil maturity as revealed by fourier transform ion cyclotron resonance mass spectrometry

A pyrolysis experiment was carried out on a Dongying Depression kerogen sample to separate the resin from the oil. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with a positive-ion detector was used to detect the relative proportional changes in the compounds of the resin. During the whole pyrolysis experiment, the relative ratio of resin exceed 10% of the soluble component at each temperature point. Five compounds were detected from the resin: N1, N1O1, N1O_(2), O1, and O_(2). To research the changes in the proportions of the compounds during pyrolysis clearly, these five compounds were divided into three classes: N1, N1Ox, and Ox. The N1 class has the largest proportion in resin at the beginning of the pyrolysis, while Ox class has the least proportion. And the relationship between the number and the molecular mass of three classes compound was researched. With increasing maturity, the proportion of N1 and the N1Ox class decreased rapidly, while the Ox class increased slowly. Through researching these resin compounds, it was found that an inversion in the proportions of above three compounds appeared at the end of the oil window. At the same time, we found that the DBE and carbon number of resin compounds have changed obviously during the pyrolysis: the DBE increased, while the carbon number decreased significantly. And the details of the change of each compound have been researched. This research extends our knowledge of judging the maturity of crude oil during the pyrolysis through the characteristics of compounds in resin and provides the new index based on resin for the evaluation of thermal evolution stage and hydrocarbon generation capacity of source rocks.