Four different pulverized coals have been used to study the effects of oxygen concentration on combustion characteristics under different enriched-oxygen conditions by entrained flow reactor experiments. The results s...Four different pulverized coals have been used to study the effects of oxygen concentration on combustion characteristics under different enriched-oxygen conditions by entrained flow reactor experiments. The results show that: with the increase of oxygen concentration, the ignition temperature of four coals greatly decreases and the low volatile coals decrease faster; with the increase of oxygen concentration, the ignition mode of pulverized coal has an obviously transformation from homogeneous ignition to heterogeneous ignition, and the corresponding oxygen concentrations are about 40% and 50%-60% respectively for bituminous coal and lignite, and both about 30% for lean coal and anthracite; with the increase of oxygen concentration, the optimal pulverized coal concentrations of bituminous coal and lignite increase firstly and then decrease, but for lean coal and anthracite, the optimal pulverized coal concentrations decrease slowly with the increase of oxygen concentration.展开更多
Based on a six-cylinder direct injection diesel engine, the engine operating condition was simulated by application AVL-FIRE software coupling the n-heptane reduced mechanism containing polycyclic aromatic hydrocarbon...Based on a six-cylinder direct injection diesel engine, the engine operating condition was simulated by application AVL-FIRE software coupling the n-heptane reduced mechanism containing polycyclic aromatic hydrocarbon (PAH) formation. The simulation and its verification test were both carried out under the maximum torque point. Then, the oxygen enriched combustion was simulated on the model, and the simulated condition was oxygen volume fraction from 21% to 30%. The simulation results show that, the oxygen enrichment (from 21% to 30%) increases the peak cylinder pressure of 3.32%, advances the start of combustion of 1.6 deg and rises the peak of average temperature in cylinder and wall heat flux. Among them, at the condition of 24% O2, the change of the results is the most significant. Benzene (A1) is one of the precursors of soot generated, the analysis of its impress-cuts of the mass distribution field in cylinder shows that, the increase of oxygen concentration can significantly inhibit the formation of benzene. But the oxygen enrichment makes the combustion more sufficient, cased a rise in the cylinder temperature, an extension in high temperature area, and an increment in the NOx emission.展开更多
A relatively new method of firing of pulverized-coal (p-e) with enrichment of the p-c and preheating of the primary air is proposed by one of the authors in China. It is developed on basis of the theory of combustion ...A relatively new method of firing of pulverized-coal (p-e) with enrichment of the p-c and preheating of the primary air is proposed by one of the authors in China. It is developed on basis of the theory of combustion and is proved to be very successful in operation. Those coals, which are hard to burn, can be fired successfuly with this method of combustion. P-c burners can be easily retrofitted to this new method of combustion. The firing of such hard to burn coals can be burnt with great stability and high burn-out efficiency. Therefore, this new method of p-c firing is considered very prospective in China. It can be used widely in power stations. Its advantages in combustion and economy of operation are eminent. Patent has been granted to it by the Patent Office of China and it got good evaluation in power industry. In this article, the principle of its design and its performance arc briefly discussed.展开更多
A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coa...A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight.展开更多
The paper summarized the work on hydrogen enriched hydrocarbons combustion and its application in engines. The progress and understanding on laminar burning velocity, flame instability, flame structure flame and chemi...The paper summarized the work on hydrogen enriched hydrocarbons combustion and its application in engines. The progress and understanding on laminar burning velocity, flame instability, flame structure flame and chemical kinetics were presented. Based on funda- mental combustion, both homogeneous spark-ignition engine and direct-injection spark-ignition engine fueled with natural gas-hydrogen blends were conducted and the technical route of natural gas-hydrogen combined with exhaust gas recirculation was proposed which experimen- tally demonstrated benefits on both thermal efficiency improvement and emissions reduction.展开更多
电转气(power to gas, P2G)技术可将电能转化为天然气,在实现综合能源系统低碳经济调度方面发挥着重要作用。为解决P2G过程中O_(2)未充分利用的问题并进一步降低碳排放,文中提出一种考虑P2G富氧改进和混合光能利用的低碳综合能源系统。...电转气(power to gas, P2G)技术可将电能转化为天然气,在实现综合能源系统低碳经济调度方面发挥着重要作用。为解决P2G过程中O_(2)未充分利用的问题并进一步降低碳排放,文中提出一种考虑P2G富氧改进和混合光能利用的低碳综合能源系统。首先,利用P2G生产的O_(2)与CO_(2)混合作为助燃气体,P2G利用碳捕集的CO_(2)制造天然气供给燃气机组使用;然后,因锅炉效率受O_(2)浓度影响,通过遗传算法和Gurobi求解器的联合算法得出耗氧设备各时段的最优供氧状态;最后,通过混合光能利用提升光能效率,以减少化石能源使用。将富氧燃烧和混合光能利用引入综合能源系统,构建考虑P2G富氧改进和混合光能利用的综合能源系统低碳经济运行模型,并设置场景进行对比验证。仿真结果显示,对比富氧改进前CO_(2)排放量降低75.83%,对比无混合光能场景光能总出力增加9.79%,表明所提模型可有效降低碳排放和运行成本。展开更多
稠油富氧火驱是一种增强型火烧油层技术,通过注入高浓度氧气能有效提高稠油燃烧效率,但关于稠油富氧燃烧机理及不同含氧量下的动力学参数研究较少。为明确富氧对稠油火驱氧化特性的影响,以辽河稠油为例,利用同步热分析仪研究了不同氧气...稠油富氧火驱是一种增强型火烧油层技术,通过注入高浓度氧气能有效提高稠油燃烧效率,但关于稠油富氧燃烧机理及不同含氧量下的动力学参数研究较少。为明确富氧对稠油火驱氧化特性的影响,以辽河稠油为例,利用同步热分析仪研究了不同氧气浓度和升温速率条件下的稠油氧化热失重以及放热等特性变化,基于等转化率法计算不同转化率、不同氧气浓度下的活化能,进而利用数值模拟研究了富氧对火驱的改善效果。结果表明,富氧环境下稠油氧化仍可划分为低温氧化前、低温氧化、焦炭沉积和高温氧化4个阶段。随着氧气加量由20%增至100%,氧化反应更加强烈,反应速率更大,放热量升高,对应的焦炭沉积阶段提前20℃。不同氧气加量下活化能的变化趋势相同,在低温氧化阶段氧气浓度对活化能的影响较小,但高温氧化阶段响应剧烈,活化能降低15~25 k J/mol。在相同氧气浓度下,升温速率增加会导致热滞后现象。数值模拟研究验证了富氧条件可有效提高火驱燃烧效果。当氧气加量由30%增至50%时,累积产油量增幅为11234 m^(3);氧气加量由70%增至100%时,累积产油量增幅(3753 m^(3))较小,推荐采用50%~70%的氧气作为富氧火驱注入气。随着氧气浓度的增加,前缘温度(350~450℃)增加,提高了燃烧的稳定性,改善了常规火驱燃烧效果。展开更多
文摘Four different pulverized coals have been used to study the effects of oxygen concentration on combustion characteristics under different enriched-oxygen conditions by entrained flow reactor experiments. The results show that: with the increase of oxygen concentration, the ignition temperature of four coals greatly decreases and the low volatile coals decrease faster; with the increase of oxygen concentration, the ignition mode of pulverized coal has an obviously transformation from homogeneous ignition to heterogeneous ignition, and the corresponding oxygen concentrations are about 40% and 50%-60% respectively for bituminous coal and lignite, and both about 30% for lean coal and anthracite; with the increase of oxygen concentration, the optimal pulverized coal concentrations of bituminous coal and lignite increase firstly and then decrease, but for lean coal and anthracite, the optimal pulverized coal concentrations decrease slowly with the increase of oxygen concentration.
文摘Based on a six-cylinder direct injection diesel engine, the engine operating condition was simulated by application AVL-FIRE software coupling the n-heptane reduced mechanism containing polycyclic aromatic hydrocarbon (PAH) formation. The simulation and its verification test were both carried out under the maximum torque point. Then, the oxygen enriched combustion was simulated on the model, and the simulated condition was oxygen volume fraction from 21% to 30%. The simulation results show that, the oxygen enrichment (from 21% to 30%) increases the peak cylinder pressure of 3.32%, advances the start of combustion of 1.6 deg and rises the peak of average temperature in cylinder and wall heat flux. Among them, at the condition of 24% O2, the change of the results is the most significant. Benzene (A1) is one of the precursors of soot generated, the analysis of its impress-cuts of the mass distribution field in cylinder shows that, the increase of oxygen concentration can significantly inhibit the formation of benzene. But the oxygen enrichment makes the combustion more sufficient, cased a rise in the cylinder temperature, an extension in high temperature area, and an increment in the NOx emission.
文摘A relatively new method of firing of pulverized-coal (p-e) with enrichment of the p-c and preheating of the primary air is proposed by one of the authors in China. It is developed on basis of the theory of combustion and is proved to be very successful in operation. Those coals, which are hard to burn, can be fired successfuly with this method of combustion. P-c burners can be easily retrofitted to this new method of combustion. The firing of such hard to burn coals can be burnt with great stability and high burn-out efficiency. Therefore, this new method of p-c firing is considered very prospective in China. It can be used widely in power stations. Its advantages in combustion and economy of operation are eminent. Patent has been granted to it by the Patent Office of China and it got good evaluation in power industry. In this article, the principle of its design and its performance arc briefly discussed.
文摘A new swirl combustion device was designed and enhaneed,which realized the utilization of steel slag,achieved highly efficient and clean coal combustion,and simultaneously realized a fully elemental utilization of coal.The distribution laws of different sized particulate matter(PM)emission and the enrichment laws of elements in particles under diverse conditions(such as various excess air coefficients and different coal ratios)were systematically studied.The enrichments of PM under both non-staged and fuel-staged conditions were also investigated.The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion,and a suitable coal ratio is also beneficial for reducing PM emissions.The melted liquid steel slag drop captured the fly ash produced from pulverized combustion,thus reducing PM emission.The alkali metal elements(K,Na,and Mg),the trace elements(As and Ti).and S have an obvious enrichment tendency in PM]and PM2.5,A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al,Si,Ca,and Fe in PM),whereas in PM2.5.PM4,and PM10,the effect of different coal ratios on the enrichment of each element is slight.
文摘The paper summarized the work on hydrogen enriched hydrocarbons combustion and its application in engines. The progress and understanding on laminar burning velocity, flame instability, flame structure flame and chemical kinetics were presented. Based on funda- mental combustion, both homogeneous spark-ignition engine and direct-injection spark-ignition engine fueled with natural gas-hydrogen blends were conducted and the technical route of natural gas-hydrogen combined with exhaust gas recirculation was proposed which experimen- tally demonstrated benefits on both thermal efficiency improvement and emissions reduction.
文摘电转气(power to gas, P2G)技术可将电能转化为天然气,在实现综合能源系统低碳经济调度方面发挥着重要作用。为解决P2G过程中O_(2)未充分利用的问题并进一步降低碳排放,文中提出一种考虑P2G富氧改进和混合光能利用的低碳综合能源系统。首先,利用P2G生产的O_(2)与CO_(2)混合作为助燃气体,P2G利用碳捕集的CO_(2)制造天然气供给燃气机组使用;然后,因锅炉效率受O_(2)浓度影响,通过遗传算法和Gurobi求解器的联合算法得出耗氧设备各时段的最优供氧状态;最后,通过混合光能利用提升光能效率,以减少化石能源使用。将富氧燃烧和混合光能利用引入综合能源系统,构建考虑P2G富氧改进和混合光能利用的综合能源系统低碳经济运行模型,并设置场景进行对比验证。仿真结果显示,对比富氧改进前CO_(2)排放量降低75.83%,对比无混合光能场景光能总出力增加9.79%,表明所提模型可有效降低碳排放和运行成本。
文摘稠油富氧火驱是一种增强型火烧油层技术,通过注入高浓度氧气能有效提高稠油燃烧效率,但关于稠油富氧燃烧机理及不同含氧量下的动力学参数研究较少。为明确富氧对稠油火驱氧化特性的影响,以辽河稠油为例,利用同步热分析仪研究了不同氧气浓度和升温速率条件下的稠油氧化热失重以及放热等特性变化,基于等转化率法计算不同转化率、不同氧气浓度下的活化能,进而利用数值模拟研究了富氧对火驱的改善效果。结果表明,富氧环境下稠油氧化仍可划分为低温氧化前、低温氧化、焦炭沉积和高温氧化4个阶段。随着氧气加量由20%增至100%,氧化反应更加强烈,反应速率更大,放热量升高,对应的焦炭沉积阶段提前20℃。不同氧气加量下活化能的变化趋势相同,在低温氧化阶段氧气浓度对活化能的影响较小,但高温氧化阶段响应剧烈,活化能降低15~25 k J/mol。在相同氧气浓度下,升温速率增加会导致热滞后现象。数值模拟研究验证了富氧条件可有效提高火驱燃烧效果。当氧气加量由30%增至50%时,累积产油量增幅为11234 m^(3);氧气加量由70%增至100%时,累积产油量增幅(3753 m^(3))较小,推荐采用50%~70%的氧气作为富氧火驱注入气。随着氧气浓度的增加,前缘温度(350~450℃)增加,提高了燃烧的稳定性,改善了常规火驱燃烧效果。
