Exploring low temperature oxidation of iso-octane under atmospheric pressure

Experimental and kinetic study on the low temperature oxidation and pyrolysis of formic acid in a jet-stirred reactor

Low temperature chemistry of 1,2,4-trimethylbenzene in a blend with n-heptane

An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

ABSTRACTThe Low Temperature Oxidation (LTO) characteristics of SARA fractions isolated from light crude oil were studied applying the static oxidation experiments. The results show that the LTO reaction of SARA fractions can occur when temperature is above 50°. Under reservoir conditions, the oxidation activities of the SARA fractions were resin > aromatics > saturate. The theoretical LTO reaction rate of crude oil calculated based on the SARA oxidation characteristics is in good agreement with the measured value. Therefore, it is an effective method to reveal the LTO mechanism of crude oil by studying the LTO mechanism of SARA fractions.

A method is proposed for developing an oil deposit based on low-temperature oil oxidation as a result of initiating an exothermic reaction and subsequent injection of oxygen-containing gas into the reservoir. In the proposed method, which includes successive injection of aqueous solutions of potassium salt and sulfuric acid into the well, light oil or gas condensate is injected into the deposit before injection of the aqueous acid solution. Further, after injection of an aqueous solution of sulfuric acid into the formation, air is pumped with further pushing with water. In the method, a 16% aqueous solution of potassium dichromate is used as an aqueous solution of potassium salt. The application of the proposed technology led to an increase in the temperature in the reservoir above 200 °C and an increase in the displacement efficiency up to 19.7%. Keywords: thermal chemical treatment; production stimulation; low-temperature reservoir; enhanced oil recovery; low temperature oxidation; oil displacement.

Low temperature oxidation and its kinetics of cornstalk chars

<div class="htmlview paragraph">In February 2004 NASA released “The Vision for Space Exploration.” The important goals outlined in this document include extending human presence in the solar system culminating in the exploration of Mars. Unprocessed waste poses a biological hazard to crew health and morale. The waste processing methods currently under consideration include incineration, microbial oxidation, pyrolysis and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this project is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water.</div> <div class="htmlview paragraph">In the Phase I project, TDA Research, Inc. demonstrated the potential of a low temperature oxidation process using ozone. In the current Phase II project, TDA and NASA Ames Research Center are developing a pilot scale low temperature ozone oxidation system. We are conducting tests in a reactor design that maximizes the contact between the ozone and the waste bed. In initial tests with a large volume reactor we were able to achieve higher oxidation rates than we obtained in the Phase I portion of this project. However, on occasion, the waste began to burn rapidly, producing high temperature and pressure spikes in the reactor. Therefore, we redesigned the reactor to mitigate the rapid ignition of the waste. In initial tests, we found that adding water to the waste bed and flowing ozone through the water-waste mixture provides much better control of the low temperature oxidation process. The addition of water likely produces a more uniform temperature throughout the waste, reducing localized hot spots that initiated the rapid combustion process. In addition, we have obtained better agreement between the gravimetric data and the results calculated with integrated CO<sub>2</sub> data, indicating that a higher percentage of waste has been oxidized to CO<sub>2</sub> and H<sub>2</sub>O before exiting the reactor.</div> <div class="htmlview paragraph">Once we have optimized the reactor design and waste oxidation process we will incorporate the design into a closed loop, fully automated system that will convert the waste into H<sub>2</sub>O and CO<sub>2</sub>, remove both compounds, and replenish the circulating gas stream with oxygen and ozone as needed. In addition, the system will contain the analytical equipment necessary to carry out a complete material balance and monitor the formation of pollutants such as NO<sub>X</sub> and SO<sub>X</sub>. At the conclusion of the project the system will be delivered to NASA Ames for their use and evaluation.</div>

Low and intermediate temperature oxidation of ethanol and ethanol–PRF blends: An experimental and modeling study

C7-C10 aromatics are indispensable components of aviation fuels to meet the swelling need for sealing rings in aero engines. Aromatics with a short and single substituent have weak low-temperature reactivity, yet this may be enhanced under a fuel blend environment. In this work, we investigated low-temperature oxidation chemistry of n-propylbenzene, a representative C9 aromatic in a blend with n-heptane, in a jet-stirred reactor. Time-of-flight molecular beam mass spectrometry using synchrotron vacuum ultraviolet radiation as a photon ionization source was used for product analysis and species identification. Thirty-six species were identified by comparison of measured photoionization efficiency curves and calculated species ionization energies, and six of them are key reaction intermediates of n-propylbenzene oxidation. Kinetic model simulations captured the measured mole fractions of reactants, main products, and intermediates with some discrepancies. Furthermore, many oxygenated aromatics are missing in the model, reflecting insufficient understanding of n-propylbenzene low-temperature chemistry. Low-temperature oxidation pathways were proposed based on molecular structures of reaction intermediates. This work explored low-temperature oxidation of n-propylbenzene under a fuel blend environment, which might be useful to unravel the low-temperature chemistry of C7-C10 aromatics in practical jet fuels.

Distinguishing between overlapping low temperature and high temperature oxidation data obtained from a pressurised flow reactor system using consolidated core material

Kinetics of the thermo-oxidative and thermal cracking reactions of Athabasca bitumen

Thermo-oxidative behavior and kinetics analysis of light and heavy oils based on TG, DSC, and FTIR

Due to the importance of gas-phase chemical reaction kinetics in low-emission combustion, stirred tank reactors have been used for decades as an experimental tool to study high- and low-temperature oxidation. A Jet-Stirred Reactor (JSR) setup is valuable to determine the evolution of species mole fractions. For the accuracy of the experimental results, it is important that a JSR is designed such that the concentration field is as homogeneous as possible in order to avoid disturbance of the chemical kinetics. In this work, numerical simulations were performed to investigate the mixing in a JSR chamber. The turbulent structures inside the JSR and the nozzles are captured using Large Eddy Simulations. We conducted numerically a parametric study to evaluate the effects of thermodynamic conditions and geometrical parameters on the mixing characteristics. More specifically, the diameter of the spherical chamber is modified together with the diameter of the nozzles through which fresh gases are fed. The characterization of the gas flow inside a typical spherical JSR layout and results derived by the normalized standard deviation of a tracer mass fraction show that a reduction of the JSR diameter at high pressures improves the homogeneity. Further, we propose a new optimized configuration consisting of six nozzles pointing to the center of the reactor which provides a more uniform composition compared to the standard JSR design.

Oxidation behaviors of Hongqian heavy crude oil characterized by TG-DSC-FTIR-MS within full temperature regions

Integration of ramped temperature oxidation and combustion tube tests for kinetic modeling of heavy oil in-Situ combustion