Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The ine...Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The inerting effect of the ionic liquid toward the low temperature oxidation process is discussed.The results show that:(1) The hydroxyl content associated with hydrogen bonds,the aliphatic methyl content,the methylene group content,and the ether oxygen bond content are reduced in the treated coal.At the same time the content of aromatic C@C bonds is constant but these chemical bonds weaken and some substituted aromatic hydrocarbon content increases while other types decrease.This demonstrates that(AMIm)Cl dissolves and destroys the coal surface microstructure;(2) The oxygen consumption of the treated coal is less than what is seen in raw coal.The CO,CO 2,C 2 H 4,and C 2 H 6 content from the treated coal is reduced compared to the untreated coal;(3) The apparent activation energy for the oxidizing reaction is different in the treated and raw coals.Micro-structural changes and macroscopic gas production allow us to conclude that(AMIm)Cl can effectively inhibit low temperature oxidation of coal.展开更多
By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characterist...By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that： 1） a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained： increases are almost identical and the initial CO is low; 2） the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3） the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4） the optimum sizes of particle, 0.125-0.25 ram, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5） the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained,展开更多
During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There ...During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There is a time delay from the injection to ignition.There are mixed results regarding the feasibility of spontaneous ignition in real-field projects and in laboratory experiments.No analytical model is available in the literature to estimate the oxidation time required to reach spontaneous ignition with heat loss.This paper discusses the feasibility of spontaneous ignition from theoretical points and experimental and field project observations.An analytical model considering heat loss is proposed.Analytical models with and without heat loss investigate the factors that affect spontaneous ignition.Based on the discussion and investigations,we find that it is more difficult for spontaneous ignition to occur in laboratory experiments than in oil reservoirs;spontaneous ignition is strongly affected by the initial reservoir temperature,oil activity,and heat loss;spontaneous ignition is only possible when the initial reservoir temperature is high,the oil oxidation rate is high,and the heat loss is low.展开更多
基金support from the National Natural Science Foundation of China (No.51074159)The Graduate Scientific Research Innovation Programme of Jiangsu Province Ordinary University (No. CXZZ12_0957)
文摘Fourier transform infrared spectroscopy(FTIR) and constant heating rate experiments were performed to study the low temperature oxidation of coal treated by an ionic liquid,1-allyl-3-methylimidazolium chloride.The inerting effect of the ionic liquid toward the low temperature oxidation process is discussed.The results show that:(1) The hydroxyl content associated with hydrogen bonds,the aliphatic methyl content,the methylene group content,and the ether oxygen bond content are reduced in the treated coal.At the same time the content of aromatic C@C bonds is constant but these chemical bonds weaken and some substituted aromatic hydrocarbon content increases while other types decrease.This demonstrates that(AMIm)Cl dissolves and destroys the coal surface microstructure;(2) The oxygen consumption of the treated coal is less than what is seen in raw coal.The CO,CO 2,C 2 H 4,and C 2 H 6 content from the treated coal is reduced compared to the untreated coal;(3) The apparent activation energy for the oxidizing reaction is different in the treated and raw coals.Micro-structural changes and macroscopic gas production allow us to conclude that(AMIm)Cl can effectively inhibit low temperature oxidation of coal.
基金Project 50474067 supported by National Natural Science Foundation of China
文摘By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that： 1） a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained： increases are almost identical and the initial CO is low; 2） the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3） the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4） the optimum sizes of particle, 0.125-0.25 ram, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5） the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained,
基金supported by the National Natural Science Foundation of China (No.51974334)Hainan Province Science and Technology Special Fund (ZDYF2022SHFZ107)local efficient reform and development funds for personnel training projects supported by the central government,Heilongjiang Postdoctoral Scientific Research Fund (LBH-Q21012)。
文摘During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There is a time delay from the injection to ignition.There are mixed results regarding the feasibility of spontaneous ignition in real-field projects and in laboratory experiments.No analytical model is available in the literature to estimate the oxidation time required to reach spontaneous ignition with heat loss.This paper discusses the feasibility of spontaneous ignition from theoretical points and experimental and field project observations.An analytical model considering heat loss is proposed.Analytical models with and without heat loss investigate the factors that affect spontaneous ignition.Based on the discussion and investigations,we find that it is more difficult for spontaneous ignition to occur in laboratory experiments than in oil reservoirs;spontaneous ignition is strongly affected by the initial reservoir temperature,oil activity,and heat loss;spontaneous ignition is only possible when the initial reservoir temperature is high,the oil oxidation rate is high,and the heat loss is low.
