SARA saturates aromatics resins and

Table 10.2 presents the total coke yields and the nonvaporized hydrocarbons produced over a spent catalyst obtained with different feedstocks. The catalyst used was deactivated for 20 hours, 30 ReDox cycles, and 50% steam. When the 100% vacuum gas oil (VGO) is replaced with a mixture of 5%w DMO-VGO and/or 30%w DMO-VGO an increase of 30% and 120% in the coke yields was observed. While the spent catalyst from VGO cracking does not have adsorbed hydrocarbons, the mixture with DM0 does, becoming almost 1% for the mixture with 30%w DM0. The SARA (saturates, aromatics, resins, and asphaltenes) analysis of these hydrocarbons showed a high concentration of asphaltenes. 

In general terms, group-type analysis of petroleum is often identified by the acronyms for the names PONA (paraffins, olefins, naphthenes, and aromatics), PIONA (paraffins, Ao-paraffins, olefins, naphthenes, and aromatics), PNA (paraffins, naphthenes, and aromatics), PINA (paraffins, Ao-paraffins, naphthenes, and aromatics), or SARA (saturates, aromatics, resins, and asphaltenes). However, it must be recognized that the fractions produced by the use of different adsorbents will differ in content and will also be different from fractions produced by solvent separation techniques. 

Conversion (upgrading) of bitumen and heavy oils to distillate products requires reduction of the MW and boiling point of the components of the feedstocks. The chemistry of this transformation to lighter products is extremely complex, partly because the petroleum feedstocks are complicated mixtures of hydrocarbons, consisting of 10 to 10 different molecules. Any structural information regarding the chemical nature of these materials would help to understand the chemistry of the process and, hence, it would be possible to improve process yields and product quality. However, because of the complexity of the mixture, the characterization of entire petroleum feedstocks and products is difficult, if not impossible. One way to simpHfy this molecular variety is to separate the feedstocks and products into different fractions (classes of components) by distillation, solubility/insolubility, and adsorption/desorption techniques. For bitumen and heavy oils, there are a number of methods that have been developed based on solubility and adsorption. The most common standard method used in the petroleum industry for separation of heavy oils into compound classes is SARA (saturates, aromatics, resins, and asphaltenes) analysis. Typical SARA analyses and properties for Athabasca and Cold Lake bitumens, achieved using a modified SARA method, are shown in Table 1. For comparison, SARA analysis of Athabasca bitumen by the standard ASTM method is also shown in this table. The discrepancy in the results between the standard and modified ASTM methods is a result of the aromatics being eluted with a... 

The chemistry of resid upgrading is extremely complicated. " This is in part due to the complexity of the ehemical nature of the feedstoeks. In order to understand the chemistry of upgrading, it would be helpful to reduee this complexity prior to reaction, by separating the feedstocks (bitumen and heavy oils) into well-known components such as SARA - saturates, aromatics, resins and asphaltenes - which are useful tools in understanding bitumen chemistry. 

SARA (Saturates, Aromatics, Resins, Asphaltenes) analysis is widely practiced on heavy fractions such as vacuum and atmospheric residues and vacuum distillates for two purposes ... 

SARA analysis a method of analysis for saturates, aromatics, resins, and asphaltenes. 

Asphalt is thought of as a colloidal system similar to petroleum, the difference being that the lighter molecules have been removed from asphalt during the refining process. Asphalt can be fractionated into four important fractions saturates, aromatics, resins, and asphaltenes by either the SARA method or the ASTM D4124 process (standard test method for separation of asphalt into four fractions). The fractionated part of saturates and aromatics is generally considered to be gas-oil. The polarity of these four fractions increases from saturates —> aromatics —> resins —> asphaltenes. 

Because the asphalt system is not a true solution, it can be fractionated into saturates, aromatics, resins, and asphaltenes by the solvent fraction method, SARA method, or TLC method. The polarity of these four fractions is increased in the order of saturates, aromatics, resins, asphaltenes. In crude oil, asphaltene micelles are present as discrete or dispersed particles in the oily phase. Although the asphaltenes themselves are insoluble in gas-oil (saturates and aromatics), they can exist as fine or coarse dispersions, depending on the resin content. The resins are part of the oily medium but have a polarity higher than gas-oil. This property enables the molecules to be easily adsorbed onto the asphaltene micelles and to act as a peptizing agent of the colloid stabilizer by charge neutralization. 

Muller et al. used SCS derivatives to study the effects of hydrodesulfurization (HDS) on polycyclic aromatic sulfur heterocycles (PASHs) in bitumen residua. Their experiments concentrated on PASHs, which is a predominant class of SCS in vacuum residue bottoms. Asphaltenes were removed by precipitation, followed by the separation of aromatic fractions from saturated fractions by the saturates, aromatics, resins, and asphalts (SARA) method. Several methods can be deployed as the SARA method depending on the type of petroleum sample, one of the more common for more viscous oils is a combination of two methods ASTM D2007 and ASTM D893. Pentane-insoluble (PI) method ASTM D893 is used first to identify the asphaltene content then ASTM D2007 is used to calculate the saturates, aromatics, and resins. 

Analytical methods such as thin layer chromatography with flame ionization detection (TLC-FID) (Karlsen barter, 1991) are widely used in the oil industry. These solubdity based separation methods allow for the investigation of crude oil components based on polarity. However they can yield very different amounts of Saturates, Aromatics, Resins and Asphaltenes (SARA) depending on the nature of solvents used in the sepraration. At a p>anel discussion on standardization of petroleum fractions held at the 2009 Petrophase conference, a need to unify and improve the separation methods for asphaltenes and resins was expressed (Merino-Garcia et al., 2010). The diversity of operating definitions employed and measurement variability affect the ability of researchers to determine whether compound classes are present and to draw cross-comp>arisons among measurements from different... 

Aske, N., Hallevik, H., Sjoblom, J., (2001), Determination of Saturate, Aromatic, Resin, and Asphaltenic (SARA) components in crude oils by means of infrared and Near-Infrared Spectroscopy, Energy Fuels, 15,1304-1312. 

These components can be separated by simple technique known as SARA analysis (Saturated, Aromatic, Resin and Asphaltenes). Some examples of the resin and asphaltenes that can be separated by using SARA analysis of are given in Figure 7a b. The SARA analysis process is shown in Figure 8. Particles such as silica, clay, iron oxides, etc. can be... 

SARA An abbreviation for saturates, aromatics, resins, and asphaltenes, which are the four solubility classes of hydrocarbon fractions of crude oil. The saturates are generally iso- and cyclo-paraffins whereas aromatics, resins, and asphaltenes form a continuum of molecules with increasing molecular weight, aromaticity, and heteroatom contents. Asphaltenes can also contain metals such as niclml and vanadium. A SARA analysis is a method used forthecharacterizationofheavy oils based onfractionation. 

Colloidal instability index (CII). This index expresses the stability of asphaltenes in terms of SARA (Saturates, Aromatics, Resins, Asphaltenes) fractions and is defined as the mass ratio between the sum of asphaltenes and unfavorable components of its stability in the oil, i.e., its flocculants (Saturates) and the sum of peptizing agents (aromatics and resins), which are components favorable to the stability of asphaltenes present in a specific oil (Asomaning, 2003) ... 

Regarding feed characterization, there is a need to characterize the residue from commonly available information without losing its essential characteristics. Typical feed analysis consists of distillation curve, kinematic viscosity, specific gravity, and sulfur, asphaltenes, and CCR residue contents. To develop more detailed kinetic models, advanced characterization is necessary for instance, SARA (saturates, aromatics, resins, asphaltenes) composition and analysis of each component would improve the prediction capability of kinetic models. 

The extracts were fractionated by a Preparative Liquid Chromatography method - PLC-8 [2], in eight distinct chemical classes FI-saturated hydrocarbons (HC), F2-monoaromatics, F3-diaromatics, F4-triaromatics, F5-polynuclear aromatics, F6-resins, F7-asphaltenes and F8-asphaltols. This method, proposed by Karam et al. as an extension of SARA method [4], was especially developed for coal-derived liquids. It combines solubility and chromatographic fractionation, affording discrete, well-defined classes of compounds which are readable for direct chromatographic and spectroscopic analysis. 

The hydrocarbons present in oil can be classified into four main classes saturated (alkanes and cycloparaffins), aromatics (hydrocarbons, mono, di and polyaromatic), resins (fractions consist of polar molecules containing heteroatoms such as N, O or S) and asphaltenes (they are molecules similar to the resins, but with a higher molecular weight and polyaromatic core). This classification is known as SARA (Wang et al, 2002 Speight, 2001 Tissot and Welt, 1978). 

---