Sorption of Athabasca Vacuum Residue Constituents on Synthetic Mineral and Process Equipment Surfaces from Mixtures with Pentane

Abstract

Deposition of organic material on mineral and process equipment surfaces poses production, transport, and refining challenges for the petroleum industry. For high-asphaltene content hydrocarbon resources, such as bitumen, deposits are frequently assumed to be asphaltene rich. In this work, deposits formed from Athabasca vacuum residue (AVR) comprising 32 wt % asphaltenes + pentane mixtures on acidic (FeS, SiO2) and basic (Fe2O3/FeOOH/FeO, Ni/NiO/NiOH) substrates are analyzed using X-ray photoelectron spectroscopy. Control experiments with pure compounds are used to confirm experimental protocols and to address substrate contamination, which interferes with deposit composition measurements, if the organic deposit is thin or surface coverage is partial. Substrate properties are found to affect both deposit thickness and deposit composition. On basic substrates, deposits are thinner and are enriched in sulfur relative to AVR. On acidic substrates, deposits are thicker and are sulfur deficient relative to AVR, even though asphaltenes, which are rich in sulfur, sorb more strongly on acidic substrates in the absence of competition from other species. Deposit composition was also found to be invariant with the composition and phase behavior of the AVR + pentane mixtures. These results were not expected.

Effect of Textural Properties and Surface Chemical Nature of Silica Nanoparticles from Different Silicon Sources on the Viscosity Reduction of Heavy Crude Oil

“…76 Nevertheless, a different behavior has been encountered regarding the acid−base interactions as it has been determined that the initial attractive asphaltene− adsorbent force is dominated by the presence of N-containing functional groups, 77 i.e., the monolayers formed by the initially adsorbed asphaltenes contain more polar species, and the additional layers in a multilayer assembly are formed mainly through van der Waals forces, H-bonding, and π−π stacking. 78 In this regard, sulfur has been established to have a minor role in asphaltene adsorption compared to other species with oxygen and nitrogen in their structure 65,79 and is mainly related to the fact that the nitrogen groups, which are partially positively charged, can produce acid−base interactions with the typically acidized sorbent surfaces. This behavior leads to an increase in asphaltene adsorption as the nitrogen content increases in the oil-heavy fractions.…”

“…In this regard, sulfur has been established to have a minor role in asphaltene adsorption compared to other species with oxygen and nitrogen in their structure , and is mainly related to the fact that the nitrogen groups, which are partially positively charged, can produce acid–base interactions with the typically acidized sorbent surfaces. This behavior leads to an increase in asphaltene adsorption as the nitrogen content increases in the oil-heavy fractions. ,, This increased adsorption is derived from the explained acid–base interactions, which in silica surfaces are enhanced by the presence of hydroxyl Si–OH functional groups (silanol), as the partially positive charged nitrogen species are enabled to interact with the negatively charged silanol groups. − …”

A New Model for Describing the Adsorption of Asphaltenes on Porous Media at a High Pressure and Temperature under Flow Conditions

“…In another study, 37 it was found that the capacity of adsorption of asphaltenes onto illite has a linear correlation with increasing the content of C and S. It has been also reported 84 that for the asphaltenes adsorbed onto basic surfaces present higher concentration of sulfur, however the total adsorbed amount of the asphaltenes was lower compared with the adsorbed amount over acid surfaces which bind more quickly or strongly to lower sulfur-containing species. 19,84 According to Curtis et al, 85 the adsorption of model asphaltenes compounds onto dry silica followed the order phenylsulfoxide > quinoline > phenol > benzoic acid > benzophenone > benzylbenzoate > pyrene. As shown in Figure 4 and Table 2, there is excellent agreement between the SLE-RC model and the experimental results with RMSE% values < 2%.…”

Understanding Adsorption of Violanthrone-79 as a Model Asphaltene Compound on Quartz Surface Using Molecular Dynamics Simulations

“…Over the past decade, many studies have examined asphaltene adsorption on minerals. − Several studies suggested that in toluene and heptol (mixture of n -heptane and toluene) solutions, asphaltenes or their aggregates did not penetrate into the interlayers of clays and were adsorbed only on their surfaces. , Both monolayer and multilayer adsorption have been observed in experiments. − For example, Dudášová et al investigated the adsorption of asphaltenes from five different origins onto minerals and clays (kaolin, CaCO 3 , BaSO 4 , FeS, Fe 3 O 4 , TiO 2 , and SiO 2 ) in heptol and found that the Langmuir isotherm model fitted well to all of the experimental isotherms. Their results indicated that the adsorption of asphaltenes was in the form of a monolayer, and the adsorption capacities were determined to vary from 0.26 to 3.78 mg/m 2 .…”