Low-Temperature Oxidation of Oils in Terms of SARA Fractions: Why Simple Reaction Models Don't Work

2003 ◽  
Author(s):  
N.P. Freitag ◽  
B. Verkoczy
Keyword(s):  
Low Temperature ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Simple Reaction ◽  
Reaction Models ◽  
Sara Fractions

Evaluation of heat release caused by low-temperature oxidation of heavy oil and its SARA fractions under isothermal conditions

2020 ◽  
Vol 690 ◽  
pp. 178690
Author(s):  
Shuai Zhao ◽  
Wanfen Pu ◽  
Mikhail A. Varfolomeev ◽  
Hao Ren ◽  
Ai Kenjiang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Heavy Oil ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Isothermal Conditions ◽  
Sara Fractions

scholarly journals Catalytic Effect of Cobalt Additive on the Low Temperature Oxidation Characteristics of Changqing Tight Oil and Its SARA Fractions

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2848 ◽  
Author(s):  
Tengfei Wang ◽  
Jiexiang Wang
Keyword(s):  
Low Temperature ◽  
Oil Recovery ◽  
Catalytic Effect ◽  
Addition Reaction ◽  
Tight Oil ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Bond Scission ◽  
Sara Fractions ◽  
Oxygen Addition

Air flooding is a potential enhanced oil recovery (EOR) method to economically and efficiently develop a tight oil reservoir due to its sufficient gas source and low operational costs, during which low temperature oxidation (LTO) is the key to ensuring the success of air flooding. In addition to inefficiency of conventional LTO, air flooding has seen its limited applications due to the prolonged reaction time and safety constraints. In this paper, a novel air injection technique based on the catalyst-activated low temperature oxidation (CLTO) is developed to improve the operational safety together with its oil recovery in tight oil reservoirs. Experimentally, static oxidation experiments are conducted to examine the influence of the catalyst on the LTO reaction kinetics of Changqing tight oil and its fractions. The catalytic oxidation characteristics are identified by applying a thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR) with respect to tight oil and its SARA (i.e., saturates, aromatics, resins, and asphaltenes) fractions. Accordingly, the catalyst can obviously decrease the LTO reaction activation energy of the Changqing tight oil and its SARA fraction. Cobalt additive can change the LTO reaction pathways of the SARA fractions, i.e., promoting the formation of hydroxyl-containing oxides and CO2 from the oxidation of saturates, aromatics and resins, while inhibiting the formation of ethers from the oxidation of aromatics and resins. The LTO of each SARA fraction contains both oxygen addition reaction and bond scission reaction that can be effectively promoted with the cobalt additive. The catalytic effect on the bond scission reaction is continuously enhanced and becomes gradually stronger than that on the oxygen addition reaction as the reaction proceeds.

Behavior and Effect of SARA Fractions of Oil During Combustion

2000 ◽  
Vol 3 (05) ◽  
pp. 380-385 ◽  
Author(s):  
M.V. Kok ◽  
C.O. Karacan
Keyword(s):  
Low Temperature ◽  
Crude Oil ◽  
Combustion Process ◽  
Crude Oils ◽  
Low Temperature Oxidation ◽  
In Situ Combustion ◽  
Temperature Oxidation ◽  
Sara Fractions ◽  
Fuel Deposition

Summary In this study, saturate, aromatic, resin, and asphaltene fractions of two Turkish crude oils (medium and heavy) were separated by column chromatographic techniques. Combustion experiments were performed on whole oils and fractions by a thermogravimetric analyzer (TG/DTG) and differential scanning calorimeter (DSC) by using air and a 10°C/min heating rate. TG and DSC data were analyzed for the determination of weight loss due to possible reactions, and for reaction enthalpies of individual fractions, which have to be known for in-situ combustion technology utilization. Introduction In-situ combustion is a process of recovering oil thermally, by igniting the oil to create a combustion front that is propagated through the reservoir by continuous air injection. Success of such a process depends mainly on the crude oil properties and rock properties as well as operational conditions. In-situ combustion is considered as an effective process not only for heavy oil reserves but also for depleted light and medium oil reservoirs. Unfortunately, the lack of better understanding of the process variables in terms of the conversion of oil during combustion and reservoir characteristics, as well as the costs, limits the more effective application of this technology. In combustion, three different reaction regions were identified, known as low-temperature oxidation, fuel deposition, and high-temperature oxidation. In low-temperature oxidation (LTO), mainly small and weak chains of hydrocarbons are broken and pyrolyzed and oxidized to give ketones, alcohols, etc. In fuel deposition or middle-temperature oxidation, products of low-temperature oxidation are transformed to heavier hydrocarbons to be combusted at higher temperatures. High-temperature oxidation (HTO) is the main combustion region where hydrocarbons are fully oxidized by air. During the course of these processes, hydrocarbons are continuously converted to other types of hydrocarbons, which makes the combustion process very complicated. Heat values and reaction parameters of crude oils are also obtained from differential scanning calorimeter (DSC) thermogravimetry (TG/DTG) experiments. Many studies have been conducted on different phases of the in-situ combustion process, mainly on the fluid and rock interactions during combustion of the fluid phase. Vossoughi et al.1 concluded that the addition of clay to porous media significantly affected the combustion of crude oil. Bae2 investigated the thermo-oxidative behavior and fuel forming properties of various crude oils. The results indicated that oils could be classified according to their oxidation characteristics. Vossoughi3 has used TG/DTG and DSC techniques to study the effect of clay and surface area on the combustion of selected oil samples. The results indicate that there was a significant reduction in the activation energy of the combustion reaction regardless of the chemical composition of additives. Vossoughi and Bartlett4 have developed a kinetic model of the in-situ combustion process from thermogravimetry and differential scanning calorimeter. They used the kinetic model to predict fuel deposition and combustion rate in a combustion tube. Kok5 characterized the combustion properties of two heavy crude oils by DSC and TG/DTG. Individual fractions of the crude oils have been studied before in a variety of purposes in different reactions. Ciajolo and Barbella6 used thermogravimetric techniques to investigate the pyrolysis and oxidation of some heavy fuel oils and their separate paraffinic, aromatic, polar, and asphaltene fractions. The thermal behavior of fuel oil can be interpreted in terms of the low-temperature phase in which the polar and asphaltene fractions pyrolyze and leave a particular carbon residue. Ranjbar and Pusch7 studied the effect of oil composition, characterized on the basis of light hydrocarbons, resin, and asphaltene contents, on the pyrolysis kinetics of the oil. The results indicate that the colloidal composition of oil, as well as the transferability and heat transfer characteristics of the pyrolysis medium, has a pronounced influence on the fuel formation and composition. Karacan and Kok8 studied the pyrolysis behavior of crude oil saturate, aromatic, resin, and asphaltene (SARA) fractions to determine the effect of each constituent to the overall pyrolysis behavior of oils. Several authors, such as Geffen,9 Iyoho,10 and Chu11 have conducted feasibility studies for the in-situ combustion process. Yannimaras and Tiffin12 applied the accelerating rate calorimetry to screen crude oils for applicability of the air-injection/in-situ combustion process. Testing was performed at reservoir conditions for four medium and high gravity oils and results were compared with the combustion tube and air-injection/in-situ combustion process on the basis of continuity of the resulting plot in the region between the LTO and HTO reactions. Although combustion studies on both oil samples and oil-rock mixtures had been conducted, studies on the behavior of crude oil SARA fractions under an oxidizing environment and the investigations on the effects of each of these fractions to the whole oil combustion process have been scarce. This research was conducted to fulfill this partial need in the field of crude oil combustion. The results are aimed to serve for better understanding and accurate modeling of in-situ combustion by using the effects of individual fractions on whole oil combustion. This enables the operators to adapt the changes in the compositional properties of oil during combustion and fine tune the operational parameters.

The low temperature oxidation characteristics of SARA fractions in air flooding process

2018 ◽  
Vol 36 (15) ◽  
pp. 1125-1130 ◽  
Author(s):  
Tengfei Wang ◽  
Jiexiang Wang ◽  
Xingbang Meng ◽  
Guoyu Chu ◽  
Chang Liu
Keyword(s):  
Low Temperature ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Oxidation Characteristics ◽  
Sara Fractions

scholarly journals Influence of Co-Precipitation Agent on the Structure, Texture and Catalytic Activity of Au-CeO2 Catalysts in Low-Temperature Oxidation of Benzyl Alcohol

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 641
Author(s):  
Lukasz Wolski ◽  
Grzegorz Nowaczyk ◽  
Stefan Jurga ◽  
Maria Ziolek
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Benzyl Alcohol ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Oxidation Of Benzyl Alcohol ◽  
Key Factor ◽  
Au Particle Size ◽  
Co Precipitation

The aim of the study was to establish the influence of a co-precipitation agent (i.e., NaOH–immediate precipitation; hexamethylenetetramine/urea–gradual precipitation and growth of nanostructures) on the properties and catalytic activity of as-synthesized Au-CeO2 nanocomposites. All catalysts were fully characterized with the use of XRD, nitrogen physisorption, ICP-OES, SEM, HR-TEM, UV-vis, XPS, and tested in low-temperature oxidation of benzyl alcohol as a model oxidation reaction. The results obtained in this study indicated that the type of co-precipitation agent has a significant impact on the growth of gold species. Immediate co-precipitation of Au-CeO2 nanostructures with the use of NaOH allowed obtainment of considerably smaller and more homogeneous in size gold nanoparticles than those formed by gradual co-precipitation and growth of Au-CeO2 nanostructures in the presence of hexamethylenetetramine or urea. In the catalytic tests, it was established that the key factor promoting high activity in low-temperature oxidation of benzyl alcohol was size of gold nanoparticles. The highest conversion of the alcohol was observed for the catalyst containing the smallest Au particle size (i.e., Au-CeO2 nanocomposite prepared with the use of NaOH as a co-precipitation agent).

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