高压高湿氧燃烧条件下CO、H2及其混合气的层流火焰特性

To achieve efficient and low-carbon energy conversion，oxy-coal combustion steam system of near-zero emissions (OCCSS) was proposed. The syngas from coal burns with pure oxygen in which water is sprayed into gradually to produce a combustion environment which is of high temperature, high pressure, high steam concentration and high oxygen concentration(namely, "four high" condition). The resultant combustion gas mixture (in which water vapor accounts for about 90%, and the rest is mainly CO2) pass through the advanced turbine and generate electricity.The exhaust gas from the turbines is condensed into water and the remains is CO2 of high concentrations, which makes CO2 capture very low-cost. In this project studies are made on the laminar flame characteristics of syngas in the innovative combustion system operation condition. The flammability limit of CO, H2 and their mixtures premixed with oxygen under high pressure and high steam concentration conditions are studied in the laser ignition experimental facility. The premixed laminar flame speed and laminar flame structure of CO, H2 and their mixtures under "four high" conditions are studied in the high pressure flame characteristics experimental facility. Through simulation and theoretical analyse, the flame propagation mechanism of CO, H2 and their mixture under "four high" conditions is obtained. This fundamental study will lay the theoretical foundation for the development of oxy-coal combustion steam system of near-zero emissions, and will derive new growth and development to the science of combustion.

为实现高效低碳能源转化，提出基于煤基合成气-氧-水蒸气燃烧方式的近零排放发电系统，即对原煤进行预处理得到合成气，采用纯氧燃烧，逐级喷入水形成高温、高压、高水蒸气浓度和高氧浓度（即"四高"）的燃烧环境，产生的混合气体（水蒸气约90%，其余主要是CO2）推动先进的透平做功，排气冷凝为水和高浓度的CO2，实现CO2的低成本捕集。本项目针对新型燃烧方式下煤基合成气的层流火焰特性进行研究，利用激光强迫点火实验装置研究高压高水蒸气浓度条件下CO、H2及其混气/O2燃烧火焰传播极限；利用增压燃烧火焰特性试验台研究"四高"条件下CO、H2及其混气层流火焰传播速度和火焰结构；通过模拟研究和理论分析，揭示CO、H2及其混气在"四高"条件下的火焰传播机理。上述研究将为煤基燃料-氧-水蒸气燃烧等相关过程的发展奠定理论基础，并将会给燃烧学的发展带来新的学科生长点。

化石燃料的燃烧带来了严重的环境问题，开发高效零排放燃烧技术迫在眉睫，纯氧燃烧技术是目前最具潜力的清洁燃烧技术之一。为了实现能源的高效低碳转化，本项目提出煤基燃料氧水蒸气燃烧零排放发电技术，基于煤基燃料氧水蒸气燃烧的概念，研究O2/H2O气氛下CO/H2的层流火焰特性和详细化学反应机理，获得了不同当量比、H2含量、预热温度、水蒸气含量和压力下的层流火焰速度和火焰结构的基础数据，揭示了不同条件对CO/H2的燃烧过程和基元反应路径的影响规律，建立了适用于O2/H2O气氛下燃烧的详细基元反应机理。为高水蒸气浓度下煤基燃料的高效清洁燃烧提供理论指导，填补了高H2O浓度下富氧燃烧基础数据的空白。.建立了加压火焰特性激光诊断实验台，实现了对层流火焰速度和火焰结构的OH-PLIF诊断；采用本生灯面积法计算了层流火焰速度。采用平焰燃烧器对OH-PLIF系统OH自由基浓度进行了定量标定，获得了定标火焰OH浓度和OH-PLIF系统下荧光强度的比例因子。.对于CO/H2在O2/H2O气氛下的燃烧，已有化学反应机理的计算结果分散性较大， O2/H2O气氛下的燃烧机理缺乏。基于不同文献中最新报道的单个基元反应动力学的研究，建立了适用于O2/H2O气氛的燃烧反应机理。本项目采用定容燃烧弹实验台测量了不同预热温度、H2含量和水蒸气含量下的火焰传播极限，可燃极限随预热温度、H2的增加而降低，随水蒸气含量的增加呈现非单调性变化规律。.采用加压火焰特性实验台研究了不同条件下CO/H2的层流火焰速度。采用OH-PLIF方法测量了本生灯火焰中的温度和OH浓度分布。随着H2含量的增加，层流火焰速度先缓慢增加，后快速增加；本生灯火焰OH自由基的浓度逐渐增大。随着预热温度的升高，层流火焰速度呈指数规律增大。低H2含量时，随着水蒸气含量的增加，火焰中OH的浓度先增大后减小，层流火焰速度先增大后下降；H2含量大于15%时，随着水蒸气含量的增加，层流火焰速度逐渐下降。随着压力的升高，火焰中H、O和OH自由基的浓度降低，而HO2自由基的浓度升高，层流火焰速度整体减小。