scholarly journals Methodology for calculating the pre-exponential factor using the isoconversional principle for the numerical simulation of the air injection process

2019 ◽  
Vol 9 (1) ◽  
pp. 37-46
Author(s):  
Jorge Mario Padilla- Reyes ◽  
Marta Liliana Trujillo -Portillo ◽  
Eider Niz- Vel´asquez
Keyword(s):  
Kinetic Model ◽  
Oxidation Process ◽  
Combustion Process ◽  
Operating Conditions ◽  
Air Injection ◽  
Oil Oxidation ◽  
Temperature Oxidation ◽  
Exponential Factor ◽  
Injection Process ◽  
Kinetics Of

The main challenge to predict at Field scale the performance of an air injection process is to understand the oil oxidation process and to have a kinetic model of reactions enabling the prediction of process behavior in a reservoir numerical simulator, under different operating conditions.   Recently, the Isoconversional Principle has been implemented for studying the kinetics of reactions associated with oil oxidation during air injection, based on Ramped Temperature Oxidation tests (RTO). In different published papers, the isoconversional analysis has been used to study the oxidation characteristics of different rock-fluid systems, identify groups of dominant reactions during the crude oil oxidation process, and estimate the effective activation energy for each of the identified reactions.   However, in none of them has a procedure been established for estimating the pre-exponential factor, as this is not a direct measure of isoconversional methods. In this article, a mathematical procedure is proposed for estimating the pre-exponential factor based on the application of Friedman's isoconversional method, inteded for characterizing the kinetics of the reactions associated with the In Situ Combustion process.  This procedure was validated with experimental information and a kinetic model proposed in the literature to model the oxidation behavior of heavy crude.

Mechanisms and kinetics of initial pyrolysis and combustion reactions of 1,1-diamino-2,2-dinitroethylene from density functional tight-binding molecular dynamics simulations

2019 ◽  
Vol 97 (11) ◽  
pp. 795-804 ◽  
Author(s):  
Dong Xiang ◽  
Weihua Zhu
Keyword(s):  
Activation Energy ◽  
Molecular Dynamics ◽  
Density Functional ◽  
Tight Binding ◽  
Combustion Process ◽  
Exponential Factor ◽  
Three Stages ◽  
Dynamics Simulations ◽  
Combustion Processes ◽  
Kinetics Of

The density functional tight-binding molecular dynamics approach was used to study the mechanisms and kinetics of initial pyrolysis and combustion reactions of isolated and multi-molecular FOX-7. Based on the thermal cleavage of bridge bonds, the pyrolysis process of FOX-7 can be divided into three stages. However, the combustion process can be divided into five decomposition stages, which is much more complex than the pyrolysis reactions. The vibrations in the mean temperature contain nodes signifying the formation of new products and thereby the transitions between the various stages in the pyrolysis and combustion processes. Activation energy and pre-exponential factor for the pyrolysis and combustion reactions of FOX-7 were obtained from the kinetic analysis. It is found that the activation energy of its pyrolysis and combustion reactions are very low, making both take place fast. Our simulations provide the first atomic-level look at the full dynamics of the complicated pyrolysis and combustion process of FOX-7.

scholarly journals Study on the Microscopic Mechanism of Spontaneous Combustion and Oxidation Kinetics of Water-Leached Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Naifu Cao ◽  
Gang Wang ◽  
Yuntao Liang
Keyword(s):  
Kinetic Model ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Water Immersion ◽  
Combustion Process ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Temperature Oxidation ◽  
Before And After ◽  
Spontaneous Combustion Of Coal

In this article, a series of experiments have been carried out to study the spontaneous combustion and oxidation mechanism of coal after water immersion and investigate its tendency to spontaneous combustion, analyze the difficulty of spontaneous combustion of coal samples under different water immersion conditions, and establish a kinetic model of water immersion coal oxidation (taking the Bulianta 12# coal as a case study). They rely on physical oxidation adsorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry, and oil bath heating. SEM has been used to analyze the characteristics of coal pore structure under different water immersion conditions (water-saturated coal samples under different water loss conditions until the coal samples are completely dried); FTIR served to investigate the characteristics of the molecular chemical structure of the coal surface before and after the coal is immersed in water. Through programmed temperature oxidation experiments combined with FTIR analyses and gas chromatographic (GC) analysis of gaseous products, it has been possible to study the changes of molecular structure and gas products on the surface of coal samples at different temperatures and water immersion conditions. The oxidation reaction rate of the 12# coal samples of Shendong Mine’s Bulianta Mine under different water content conditions during the spontaneous combustion process has been quantitatively studied. The difficulty of spontaneous combustion of coal samples has been correspondingly addressed. A kinetic model from the perspective of oxygen consumption has been proposed. Thermogravimetry-differential scanning calorimetry (TG-DSC) has been used to analyze and study the exothermal oxidation process before and after coal immersion. From the perspective of the exothermic intensity of the coal-oxygen reaction, an oxidation kinetic model for immersed coal samples has been developed to qualitatively determine its spontaneous combustion tendency. Results have shown that the increase in the specific surface area increases the risk of spontaneous combustion, and coal samples after soaking and drying have a stronger tendency to spontaneous combustion than raw coal. The moisture content of the coal sample leading to the easiest ignition conditions is 16.05%. Regardless of the moisture content, the critical temperature is maintained at 65–75°C, and the temperature of the left coal in the goaf should be prevented from exceeding this critical value.

Kinetics of Wet In-Situ Combustion: A Review of Kinetic Models

2014 ◽  
Author(s):  
E. A. Cavanzo ◽  
S. F. Muñoz ◽  
A.. Ordoñez ◽  
H.. Bottia
Keyword(s):  
Kinetic Model ◽  
Crude Oil ◽  
Kinetic Models ◽  
Combustion Front ◽  
Chemical Interaction ◽  
Combustion Process ◽  
Oxidation Reactions ◽  
In Situ Combustion ◽  
Temperature Oxidation

Abstract In Situ Combustion is an enhanced oil recovery method which consists on injecting air to the reservoir, generating a series of oxidation reactions at different temperature ranges by chemical interaction between oil and oxygen, the high temperature oxidation reactions are highly exothermic; the oxygen reacts with a coke like material formed by thermal cracking, they are responsible of generating the heat necessary to sustain and propagate the combustion front, sweeping the heavy oil and upgrading it due to the high temperatures. Wet in situ combustion is variant of the process, in which water is injected simultaneously or alternated with air, taking advantage of its high heat capacity, so the steam can transport heat more efficiently forward the combustion front due to the latent heat of vaporization. A representative model of the in situ combustion process is constituted by a static model, a dynamic model and a kinetic model. The kinetic model represents the oxidative behavior and the compositional changes of the crude oil; it is integrated by the most representative reactions of the process and the corresponding kinetic parameters of each reaction. Frequently, the kinetic model for a dry combustion process has Low Temperature Oxidation reactions (LTO), thermal cracking reactions and the combustion reaction. For the case of wet combustion, additional aquathermolysis reactions take place. This article presents a full review of the kinetic models of the wet in situ combustion process taking into account aquathermolysis reactions. These are hydrogen addition reactions due to the chemical interaction between crude oil and steam. The mechanism begins with desulphurization reactions and subsequent decarboxylation reactions, which are responsible of carbon monoxide production, which reacts with steam producing carbon dioxide and hydrogen; this is the water and gas shift reaction. Finally, during hydrocracking and hydrodesulphurization reactions, hydrogen sulfide is generated and the crude oil is upgraded. An additional upgrading mechanism during the wet in situ combustion process can be explained by the aquathermolysis theory, also hydrogen sulphide and hydrogen production can be estimated by a suitable kinetic model that takes into account the most representative reactions involved during the combustion process.

Macro Kinetics of N-Phosphonomethyliminodiacetic Acid Catalytic Oxidation

2012 ◽  
Vol 455-456 ◽  
pp. 872-879 ◽  
Author(s):  
Yan Bao ◽  
Jia Wu ◽  
Xiao Ping Hu
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Measured Data ◽  
Second Step ◽  
Oxidizing Agent ◽  
Dissolved Oxygen Concentration ◽  
Exponential Factor ◽  
In Series ◽  
Kinetics Of ◽  
Made In

The oxidation of N-phosphonomethyliminodiacetic acid (PMIDA) to prepare glyphosate (PMG) over active carbon was investigated. Experiments were carried out with O2 as the oxidizing agent in a 150-mL autoclave made in stainless steel, with reaction temperature ranging from 323.15 to 353.25K and the pressure from 0.12 to 0.40 MPa. The macro kinetic model of the reactions in series was developed, and the pre-exponential factor and activation energy were estimated from the measured data in experiments. The influence of dissolved oxygen concentration was also considered in this macro kinetic model. The results indicated that the two step reactions are all one-order to reactant (PMIDA or PMG) and 0.3 or 0.07 to O2 respectively. The active energy was 12.98kJ/mol for the first step reaction and 10.87kJ/mol for the second step reaction.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

Investigation of Thermal Fingerprint in Accelerating-Rate Calorimetry for Air-Injection Enhanced-Oil-Recovery Processes

SPE Journal ◽  
2016 ◽  
Vol 22 (02) ◽  
pp. 548-561 ◽  
Author(s):  
S.. Bhattacharya ◽  
J. D. Belgrave ◽  
D. G. Mallory ◽  
R. G. Moore ◽  
M. G. Ursenbach ◽  
...  
Keyword(s):  
Mass Transfer ◽  
High Temperature ◽  
Kinetic Model ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Reaction Kinetic ◽  
Air Injection ◽  
Temperature Oxidation ◽  
Temperature Range ◽  
Increasing Temperature

Summary The accelerating-rate calorimeter (ARC) is unique for its exceptional adiabaticity, its sensitivity, and its sample universality. Accelerating Rate Calorimetry is one of the screening tests used to determine the suitability for air-injection enhanced oil recovery (EOR). These tests show oil reactivity and exothermicity over a broad range of temperatures: low-temperature range (LTR), negative-temperature-gradient region (NTGR), and high-temperature range (HTR). An experimental and simulation study was carried out to expand understanding and interpretation of the data derived from high-pressure closed-ARC tests. Athabasca bitumen was used for the experimental study in a closed ARC at 13.89 MPag (2000 psig) to identify the temperature ranges over which the oil reacts with oxygen in the injected air. Self-heat rate from accelerating-rate calorimetry and mass-loss rates from the differential thermogravimetric analysis show the influence of mass transfer of oxygen within bitumen in the LTR and HTR. A numerical model was developed to integrate the concept of mass transfer with a reaction-kinetic model. The model incorporates solubility of oxygen with partition equilibrium coefficient (K-value) as a medium to introduce oxygen into the bitumen layer, which later transfers throughout oil layer by diffusion. This model considers both low- and high-temperature oxidation (LTO and HTO), and thermal-cracking reactions, as described in traditional reaction-kinetic models of in-situ-combustion (ISC) processes. Results show that formation of an asphaltenes film in the LTR caused by oxidation of maltenes obstructs oxygen (mass-transfer restriction) penetration into the bitumen layer. The simulated result shows that, by integrating mass transfer with the kinetic model, it is possible to predict the NTGR. Viscosity and temperature dependence on the mass transfer of oxygen is linear. As time passes and chemical reaction becomes more important with increasing temperature, the relationship deviates from linearity. With increasing temperature, the influence of chemical interaction on the oxygen distribution becomes greater, and this results in a shorter initial stage of mass transfer of oxygen within the bitumen film at low temperatures. This implies that the ARC can be a useful tool for understanding the effect of mass transfer on the oxidation characteristic for predicting LTR, NTGR, and HTR.

scholarly journals Study on the thermal kinetics of anthracite oxidation induced by water and associated pyrite

2020 ◽  
Author(s):  
Caiping Wang ◽  
Xiadan Duan ◽  
Zujin Bai ◽  
Yang Xiao ◽  
Jun Deng
Keyword(s):  
Coal Sample ◽  
Spontaneous Combustion ◽  
Oxidation Process ◽  
Great Influence ◽  
Oxygen Absorption ◽  
Heating Rates ◽  
Temperature Oxidation ◽  
Mechanism Model ◽  
Gain Stage ◽  
Kinetics Of

Abstract Pyrite and water in coal have considerable influence on coal spontaneous combustion and threaten the safety of mine production gravely. To reveal the influence mechanism of water and associated pyrite on oxidation kinetics of coal–oxygen composite reaction, the pyrite of 0%, 1%, 2%, 4%, 6% and the moisture of 1%, 5%, 10%, 15% and 20% were mixed with the coal samples to obtain 25 coal samples. Thermogravimetric analysis technology was conducted to explore the changes of mass and characteristic temperatures of coal samples treated with water and associated pyrite during the low–temperature oxidation, and kinetic analysis of the oxidation process was discussed based on multiple heating rates(5 °C/min, 10 °C/min and15 °C/min).The results show that water and associated pyrite had a great influence on coal in oxygen absorption and weight gain stage ( T 3 ~ T 5 ), and there was a proportion range with the largest synergistic oxidation contribution. The apparent activation energy of the coal sample appeared changes, but the mechanism model did not, indicating that water and pyrite could affect the oxidation process of the coal sample externally. When water and associated pyrite exhibit synergistic interaction, there have a range that water was 10~15% and associate pyrite was 2~4% had the largest promotion and contribution to anthracite oxidation. The results have important scientific value and practical guiding significance for the further study on prediction, prevention and control of high sulfur anthracite spontaneous combustion.

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