A comprehensive analysis of hydrogen/oxygen and hydrocarbon/oxygen counterflow diffusion flames has been conducted using corresponding detailed reaction mechanisms. The hydrocarbon fuels contain n-alkanes from CH4 to ...A comprehensive analysis of hydrogen/oxygen and hydrocarbon/oxygen counterflow diffusion flames has been conducted using corresponding detailed reaction mechanisms. The hydrocarbon fuels contain n-alkanes from CH4 to C16H34. The basic diffusion flame structures are demonstrated, analyzed, and compared. The effects of pressure, and strain rate on the flame behavior and energy-release rate for each fuel are examined systematically. The detailed chemical kinetic reaction mechanisms from Lawrence Livermore National Laboratory （LLNL） are employed, and the largest one of them contains 2115 species and 8157 reversible reactions. The results indicate for all of the fuels the flame thickness and heat release rate correlate well with the square root of the pressure multiplied by the strain rate. Under the condition of any strain rate and pressure, H2 has thicker flame than hydrocarbons, while the hydrocarbons have the similar temperature and main products distributions and almost have the same flame thickness and heat release rate. The result indicates that the fuels composed with these hydrocarbons will still have the same flame properties as any pure n-alkane fuel.展开更多
Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of tran...Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of transport and injection of carbon dioxide into oil fields at Gachsaran for enhanced oil recovery in the various oil price indices is conducted and indices net present value(NPV) and internal rate of return on investment(IRR) are calculated. The results of the two models reveal that gross efficiency of the oxy fuel cycle is more than reference cycle(62% compared to 49.03%), but the net efficiency is less(41.85% compared to 47.92%) because of the high-energy consumption of the components, particularly air separation unit(ASU) in the oxy fuel cycle. In this model, pure carbon dioxide with pressure of 20×105 Pa and purity of 96.84% was captured. NOX emissions also decrease by 4289.7 tons per year due to separation of nitrogen in ASU. In this model, none of the components of oxy fuel cycle is a major engineering challenge. With increasing oil price, economic justification of oxy fuel combustion model increases. With the price of oil at $ 80 per barrel in mind and $ 31 per ton fines for emissions of carbon dioxide in the atmosphere, IRR is the same for both models.展开更多
Atmospheric oxygen （02） is the most crucial element on earth for the aerobic organisms that depend on it to release energy from carbon-based macromolecules. This is the first study to systematically analyze the glob...Atmospheric oxygen （02） is the most crucial element on earth for the aerobic organisms that depend on it to release energy from carbon-based macromolecules. This is the first study to systematically analyze the global O2 budget and its changes over the past 100 years. It is found that anthropogenic fossil fuel combustion is the largest contributor to the current O2 deficit, which consumed 2.0 Gt/a in 1900 and has increased to 38.2 Gt/a by 2015. Under the Representative Concentration Pathways （RCPs） RCP8,5 scenario, approximately 100Gt （gigatonnes） of O2 would be removed from the atmosphere per year until 2100, and the O2 concentration will decrease from its current level of 20.946% to 20.825%. Human activities have caused irreversible decline of atmospheric O2. It is time to take actions to promote O2 production and reduce O2 consumption.展开更多
文摘A comprehensive analysis of hydrogen/oxygen and hydrocarbon/oxygen counterflow diffusion flames has been conducted using corresponding detailed reaction mechanisms. The hydrocarbon fuels contain n-alkanes from CH4 to C16H34. The basic diffusion flame structures are demonstrated, analyzed, and compared. The effects of pressure, and strain rate on the flame behavior and energy-release rate for each fuel are examined systematically. The detailed chemical kinetic reaction mechanisms from Lawrence Livermore National Laboratory （LLNL） are employed, and the largest one of them contains 2115 species and 8157 reversible reactions. The results indicate for all of the fuels the flame thickness and heat release rate correlate well with the square root of the pressure multiplied by the strain rate. Under the condition of any strain rate and pressure, H2 has thicker flame than hydrocarbons, while the hydrocarbons have the similar temperature and main products distributions and almost have the same flame thickness and heat release rate. The result indicates that the fuels composed with these hydrocarbons will still have the same flame properties as any pure n-alkane fuel.
文摘Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of transport and injection of carbon dioxide into oil fields at Gachsaran for enhanced oil recovery in the various oil price indices is conducted and indices net present value(NPV) and internal rate of return on investment(IRR) are calculated. The results of the two models reveal that gross efficiency of the oxy fuel cycle is more than reference cycle(62% compared to 49.03%), but the net efficiency is less(41.85% compared to 47.92%) because of the high-energy consumption of the components, particularly air separation unit(ASU) in the oxy fuel cycle. In this model, pure carbon dioxide with pressure of 20×105 Pa and purity of 96.84% was captured. NOX emissions also decrease by 4289.7 tons per year due to separation of nitrogen in ASU. In this model, none of the components of oxy fuel cycle is a major engineering challenge. With increasing oil price, economic justification of oxy fuel combustion model increases. With the price of oil at $ 80 per barrel in mind and $ 31 per ton fines for emissions of carbon dioxide in the atmosphere, IRR is the same for both models.
基金supported by the National Natural Science Foundation of China (41521004)the China University Research Talents Recruitment Program (111 project, B13045)
文摘Atmospheric oxygen （02） is the most crucial element on earth for the aerobic organisms that depend on it to release energy from carbon-based macromolecules. This is the first study to systematically analyze the global O2 budget and its changes over the past 100 years. It is found that anthropogenic fossil fuel combustion is the largest contributor to the current O2 deficit, which consumed 2.0 Gt/a in 1900 and has increased to 38.2 Gt/a by 2015. Under the Representative Concentration Pathways （RCPs） RCP8,5 scenario, approximately 100Gt （gigatonnes） of O2 would be removed from the atmosphere per year until 2100, and the O2 concentration will decrease from its current level of 20.946% to 20.825%. Human activities have caused irreversible decline of atmospheric O2. It is time to take actions to promote O2 production and reduce O2 consumption.
